What was the true carrier of the Black Death. How did the bubonic plague spread among human populations. What are the different forms of plague and their symptoms. How is plague diagnosed and treated in modern times. What is the current prevalence of plague cases globally and in the United States.

The True Carriers of the Black Death: Humans, Not Rats

For centuries, rats have been vilified as the primary culprits behind the spread of the devastating bubonic plague, also known as the Black Death. However, recent research has challenged this long-held belief, suggesting that humans themselves were the main vectors of this deadly disease.

The misconception about rats stems from the fact that they can indeed carry the plague-causing bacteria, Yersinia pestis. But the transmission dynamics of the disease are more complex than previously thought. Let’s delve deeper into this fascinating revelation and explore the true nature of plague transmission.

The Role of Fleas in Plague Transmission

While rats are not the primary carriers, they do play a role in the plague ecosystem. Fleas that feed on infected rodents, including rats, can become carriers of the Yersinia pestis bacteria. These infected fleas can then transmit the disease to humans and other mammals during subsequent feedings.

How long can plague bacteria survive in fleas? The plague bacteria can survive for extended periods in fleas, much longer than in the blood of rodents. This prolonged survival in fleas contributes to the persistence of plague in certain environments.

Understanding the Different Forms of Plague

Plague manifests in three primary forms, each with its own set of symptoms and transmission routes. Understanding these forms is crucial for proper diagnosis and treatment.

Bubonic Plague: The Most Common Form

Bubonic plague is the most frequently encountered form of the disease. It typically results from the bite of an infected flea.

• Symptoms include sudden onset of fever, headache, chills, and weakness
• Characteristic swollen, tender, and painful lymph nodes called buboes
• Bacteria multiply in the lymph node closest to the entry point
• Can spread to other parts of the body if left untreated

Septicemic Plague: A Severe Bloodstream Infection

Septicemic plague occurs when the bacteria enter the bloodstream, leading to a severe and often fatal condition.

• Characterized by fever, chills, extreme weakness, and abdominal pain
• May cause shock and bleeding into the skin and organs
• Skin and tissues may turn black and die, particularly on extremities
• Can develop from untreated bubonic plague or occur as initial symptoms

Pneumonic Plague: The Most Dangerous Form

Pneumonic plague is the most serious and only form that can be transmitted directly from person to person through respiratory droplets.

• Symptoms include fever, headache, weakness, and rapidly developing pneumonia
• Shortness of breath, chest pain, and cough (sometimes with bloody mucus)
• Can lead to respiratory failure and shock
• May develop from inhaling infectious droplets or from untreated bubonic or septicemic plague

Human-to-Human Transmission: Unraveling the Mystery

The revelation that humans played a significant role in spreading the Black Death challenges our understanding of historical pandemics. Human-to-human transmission, particularly through the pneumonic form of plague, likely contributed to the rapid spread of the disease during medieval outbreaks.

Can plague be transmitted directly between humans? Yes, but it’s relatively rare and typically requires direct and close contact with a person suffering from pneumonic plague. When an infected individual coughs, they release droplets containing the plague bacteria into the air. If another person inhales these droplets, they can contract pneumonic plague.

The Incubation Period of Plague

Understanding the incubation period of plague is crucial for containment and treatment efforts. The time between exposure and onset of symptoms varies depending on the form of plague:

• Bubonic plague: 2 to 6 days after infection
• Pneumonic plague: 1 to 3 days after exposure to airborne bacteria

Why is the incubation period important? The short incubation period, particularly for pneumonic plague, underscores the need for rapid diagnosis and treatment to prevent severe complications and further spread of the disease.

Diagnosis and Treatment of Plague in Modern Times

Despite its historical infamy, plague remains a concern in certain parts of the world. Modern medical advancements have significantly improved our ability to diagnose and treat this ancient disease.

The Diagnostic Process

Diagnosing plague involves a combination of clinical evaluation and laboratory testing:

1. Initial evaluation by a healthcare professional
2. Collection of blood, sputum, or lymph node aspirate samples
3. Laboratory testing of samples for the presence of Yersinia pestis
4. Preliminary results available within hours
5. Final confirmation typically takes 24 to 48 hours

How quickly can plague be diagnosed? Preliminary results can be available in less than two hours, allowing for prompt initiation of treatment. However, definitive confirmation may take up to two days.

Treatment Approaches

Early diagnosis and treatment are critical for managing plague and preventing its progression to more severe forms:

• Antibiotic therapy is the primary treatment for all forms of plague
• Treatment often begins presumptively, even before laboratory confirmation
• Prompt antibiotic administration can prevent the progression of bubonic plague to more severe forms
• Supportive care may be necessary for severe cases, particularly pneumonic plague

Why is early treatment crucial? Without specific antibiotic therapy, all forms of plague can progress rapidly and potentially lead to death. Early intervention significantly improves outcomes and reduces the risk of complications.

Global and U.S. Prevalence of Plague Cases

While plague may seem like a disease of the past, it continues to occur in various parts of the world, including the United States. Understanding its current prevalence provides valuable context for public health efforts and medical preparedness.

Plague in the United States

Plague was first introduced to the United States in 1900, and since then, its presence has been carefully monitored:

• Between 1900 and 2012, 1006 confirmed or probable human plague cases occurred in the U.S.
• Over 80% of U.S. plague cases have been the bubonic form
• In recent decades, an average of 7 human plague cases are reported annually
• Cases range from 1 to 17 per year
• Plague affects people of all ages, from infants to 96-year-olds
• 50% of cases occur in individuals aged 12-45

How prevalent is plague in the United States today? While plague cases do occur, they are relatively rare, with an average of only 7 cases reported annually in recent decades.

Global Plague Prevalence

Globally, plague remains a concern in certain regions, particularly in Africa, Asia, and South America. The World Health Organization (WHO) continues to monitor plague outbreaks and supports affected countries in their control efforts.

Which regions are most affected by plague today? While specific numbers vary year to year, countries in Africa, particularly Madagascar and the Democratic Republic of Congo, have reported the highest number of plague cases in recent years.

Plague Ecology and Environmental Factors

Understanding the ecological context of plague is crucial for predicting and preventing outbreaks. The disease persists in nature through a complex interplay of bacteria, vectors, and animal hosts.

The Role of Rodents in Plague Ecology

Various rodent species serve as reservoirs for Yersinia pestis:

• Chipmunks
• Prairie dogs
• Ground squirrels
• Mice
• Other small mammals

These rodents can harbor the bacteria without necessarily succumbing to the disease, allowing it to persist in the environment.

How do environmental changes affect plague dynamics? Climate change, habitat destruction, and human encroachment into wildlife areas can all influence rodent populations and flea abundance, potentially affecting plague transmission patterns.

Geographic Distribution of Plague

Plague is found in various parts of the world, with certain regions more prone to outbreaks:

• Africa: Particularly in Madagascar and parts of sub-Saharan Africa
• Asia: Including parts of China, Mongolia, and Southeast Asia
• Americas: Southwestern United States, parts of South America

Why does plague persist in certain geographic areas? Factors such as climate, rodent population dynamics, and human-wildlife interactions contribute to the persistence of plague in specific regions.

Prevention and Control Measures for Plague

Despite its historical devastation, modern understanding of plague transmission and ecology allows for effective prevention and control strategies.

Personal Protection Measures

Individuals can take steps to reduce their risk of plague exposure:

• Avoid contact with wild rodents and their fleas
• Use insect repellent when outdoors in plague-prone areas
• Keep pets free of fleas
• Wear gloves when handling potentially infected animals

How effective are personal protection measures against plague? While not foolproof, these measures significantly reduce the risk of plague exposure in endemic areas.

Public Health Interventions

Public health authorities employ various strategies to prevent and control plague outbreaks:

• Surveillance of rodent populations and flea abundance
• Environmental management to reduce rodent habitats near human settlements
• Targeted use of insecticides to control flea populations
• Rapid response to suspected cases, including contact tracing and prophylactic treatment
• Public education about plague risks and prevention

What role does international cooperation play in plague control? Global collaboration, facilitated by organizations like the WHO, is crucial for monitoring plague activity, sharing information, and coordinating responses to outbreaks across borders.

The Impact of Modern Medicine on Plague Mortality

The advent of antibiotics and improved medical care has dramatically changed the prognosis for plague patients. Unlike in historical times, plague is now a treatable disease with a much lower mortality rate when diagnosed and treated promptly.

Antibiotic Treatment

Several antibiotics are effective against Yersinia pestis:

• Streptomycin
• Gentamicin
• Doxycycline
• Ciprofloxacin

The choice of antibiotic depends on the patient’s age, medical history, and the specific form of plague.

How has antibiotic treatment changed plague outcomes? With prompt antibiotic treatment, the mortality rate for bubonic plague has dropped from over 50% historically to less than 10% in modern times.

Supportive Care

In addition to antibiotics, modern supportive care plays a crucial role in managing severe plague cases:

• Fluid and electrolyte management
• Oxygen therapy
• Mechanical ventilation for severe pneumonic plague
• Management of complications such as septic shock

Why is supportive care important in plague treatment? Comprehensive supportive care can significantly improve outcomes, particularly for patients with septicemic or pneumonic plague who may develop life-threatening complications.

Frequently Asked Questions | Plague

What is plague?

Plague is an infectious disease that affects rodents, certain other animals, and humans. It is caused by the Yersinia pestis bacteria. These bacteria are found in many areas of the world, including the United States.

How do people become infected with plague?

People most commonly acquire plague when they are bitten by a flea that is infected with the plague bacteria. People can also become infected from direct contact with infected tissues or fluids while handling an animal that is sick with or that has died from plague. Finally, people can become infected from inhaling respiratory droplets after close contact with cats and humans with pneumonic plague.

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What are the different forms of plague?

There are three forms of plague:

• Bubonic plague: Patients develop sudden onset of fever, headache, chills, and weakness and one or more swollen, tender and painful lymph nodes (called buboes). This form is usually the result of an infected flea bite. The bacteria multiply in the lymph node closest to where the bacteria entered the human body. If the patient is not treated with appropriate antibiotics, the bacteria can spread to other parts of the body.
• Septicemic plague: Patients develop fever, chills, extreme weakness, abdominal pain, shock, and possibly bleeding into the skin and other organs. Skin and other tissues may turn black and die, especially on fingers, toes, and the nose. Septicemic plague can occur as the first symptoms of plague, or may develop from untreated bubonic plague. This form results from bites of infected fleas or from handling an infected animal.
• Pneumonic plague: Patients develop fever, headache, weakness, and a rapidly developing pneumonia with shortness of breath, chest pain, cough, and sometimes bloody or watery mucous. Pneumonic plague may develop from inhaling infectious droplets or from untreated bubonic or septicemic plague that spreads to the lungs. The pneumonia may cause respiratory failure and shock. Pneumonic plague is the most serious form of the disease and is the only form of plague that can be spread from person to person (by infectious droplets).

Forms of plague.

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What is the basic transmission cycle of plague?

Fleas become infected by feeding on rodents, such as chipmunks, prairie dogs, ground squirrels, mice, and other mammals that are infected with the bacterium Yersinia pestis. Fleas transmit the plague bacteria to humans and other mammals during a subsequent feeding. The plague bacteria survive briefly (a few days) in the blood of rodents and for longer periods in the fleas. An illustration of plague ecology in the United States is available.

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Could one person get plague from another person?

Yes, when a person has plague pneumonia they may cough droplets containing the plague bacteria into air. If these bacteria-containing droplets are breathed in by another person they can cause pneumonic plague. Human-to-human transmission is rare and typically requires direct and close contact with the person with pneumonic plague.

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What is the incubation period for plague?

A person usually becomes ill with bubonic plague 2 to 6 days after being infected. Someone exposed to Yersinia pestis through the air would become ill within 1 to 3 days.

When bubonic plague is left untreated, plague bacteria can invade the bloodstream. When plague bacteria multiply in the bloodstream, they spread rapidly throughout the body and cause a severe and often fatal condition called septicemic plague. Untreated bubonic plague can also progress into an infection of the lungs, causing pneumonic plague. If plague patients are not given specific antibiotic therapy, all forms of plague can progress rapidly to death.

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How is plague diagnosed?

The first step in plague diagnosis is evaluation by a health worker. If the health worker suspects plague, samples of the patient’s blood, sputum, or lymph node aspirate are sent to a laboratory for testing. Once the laboratory receives the sample, preliminary results can be ready in less than two hours. Laboratory confirmation will take longer, usually 24 to 48 hours. Often, presumptive treatment with antibiotics will start as soon as samples are taken, if plague is suspected.

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How many cases of plague occur in the United States? Globally?

Plague was first introduced into the United States in 1900. Between 1900 and 2012, 1006 confirmed or probable human plague cases occurred in the United States. Over 80% of United States plague cases have been the bubonic form. In recent decades, an average of 7 human plague cases are reported each year (range: 1-17 cases per year). Plague has occurred in people of all ages (infants up to age 96), though 50% of cases occur in people ages 12–45. Worldwide, between 1,000 and 2,000 cases each year are reported to the World Health Organizationexternal icon (WHO), though the true number is likely much higher.

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What is the death rate of plague?

In the pre-antibiotic era (1900 through 1941), mortality among those infected with plague in the United States was 66%. Antibiotics greatly reduced mortality, and by 1990-2010 overall mortality had decreased to 11%. Plague can still be fatal despite effective antibiotics, though it is lower for bubonic plague cases than for septicemic or pneumonic plague cases. It is hard to assess the mortality rate of plague in developing countries, as relatively few cases are reliably diagnosed and reported to health authorities. WHO cites mortality rates of 8–10%, however some studies (WHO, 2004) suggest that mortality may be much higher in some plague endemic areas.

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How is plague treated?

Plague can be successfully treated with antibiotics. Once a patient is diagnosed with suspected plague they should be hospitalized and, in the case of pneumonic plague, medically isolated. Laboratory tests should be done, including blood cultures for plague bacteria and microscopic examination of lymph node, blood, and sputum samples. Antibiotic treatment should begin as soon as possible after laboratory specimens are taken. To prevent a high risk of death in patients with pneumonic plague, antibiotics should be given as soon as possible, preferably within 24 hours of the first symptoms.

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Is the disease seasonal in its occurrence?

Yes. Although cases can occur any time of the year, most cases in the United States are acquired from late spring to early fall.

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Where is plague most common in the United States?

Plague occurs in rural and semi-rural areas of the western United States. Plague is most common in the southwestern states, particularly New Mexico, Arizona, and Colorado.

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Who is at risk for getting plague in the United States?

Human plague occurs in areas where the bacteria are present in wild rodent populations. The risks are generally highest in rural and semi-rural areas, including homes that provide food and shelter for various ground squirrels, chipmunks and wood rats, or other areas where you may encounter rodents.

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Is a vaccine available to prevent plague?

A plague vaccine is not available. New plague vaccines are in development but are not expected to be commercially available in the immediate future.

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Maybe Rats Aren’t to Blame for the Black Death

Rats have long been blamed for spreading the parasites that transmitted plague throughout medieval Europe and Asia, killing millions of people. Now, a provocative new study has modeled these long-ago outbreaks and suggests that the maligned rodents may not be the culprits after all.

The study, published on Monday in the journal PNAS, instead points the finger at human parasites—such as fleas and body lice—for primarily spreading plague bacteria during the Second Pandemic, a series of devastating outbreaks that spanned from the 1300s to the early 1800s.

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These outbreaks include the infamous Black Death, which wiped out a third of Europe’s population in the mid-1300s, amassing a body count in the tens of millions.

“The plague really transformed human history, so it’s really important to understand how it was spreading and why it was spreading so fast,” says lead study author Katharine Dean, a doctoral research fellow at the University of Oslo’s Centre for Ecological and Evolutionary Synthesis.

Deadly Bite

When fleas infected with the bacterium Yersinia pestis bite humans, the bacteria can jump into the bloodstream and congregate in humans’ lymph nodes, which are found throughout the body. The infection causes lymph nodes to swell into ghastly “buboes,” the namesakes for bubonic plague. (Find out how plague bacteria evolved.)

In cases of plague since the late 1800s—including an outbreak in Madagascar in 2017—rats and other rodents helped spread the disease. If Y. pestis infects rats, the bacterium can pass to fleas that drink the rodents’ blood. When a plague-stricken rat dies, its parasites abandon the corpse and may go on to bite humans.

Because of rats’ role in modern plagues, as well as genetic evidence that medieval plague victims died of Y. pestis, many experts think that rats also spread plague during the Second Pandemic.

In 1986, archaeologists uncovered a mass grave in East Smithfield, London, used to bury victims of the Black Death in the 1340s. At the time, one observer said that 200 victims of the plague were being buried each day.

Photograph by MOLA/Getty

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But some historians argue that the Black Death may have spread differently. For one, the Black Death tore through Europe far faster than any modern plague outbreaks. In addition, “rat falls” precede some modern outbreaks, but medieval plague records don’t mention rats dying en masse.

“Geneticists and modern historians were putting the rat into the position [of spreading the plague] and were straining bits of evidence,” says Samuel Cohn, a University of Glasgow medieval historian who has criticized the rat-flea theory.

Virtual Pandemic

As an alternative, some scholars have long toyed with the idea that fleas on humans spread the Black Death. If fleas and lice picked up the plague by biting an infected human, they could potentially hop onto a person in close quarters and transmit the disease.

Mathematically, the patterns in how disease moves through a population are different for the rat-flea and human-parasite modes of transmission. To put them to the test, Dean’s team modeled each with equations that simulated the rise and fall of an outbreak, based on how rats, fleas, and body lice would behave and spread plague.

“It’s basically bookkeeping—you see how people move [in the simulation],” says coauthor Boris Valentijn Schmid, a University of Oslo computational biologist and Dean’s Ph. D. adviser.

After running their models many times, Dean and Schmid statistically evaluated which models best matched mortality patterns from nine different European plague outbreaks from the Second Pandemic. To their surprise, they found that in seven of the nine cities they examined, the human-parasite model more closely fit mortality records than the rat-flea model.

“It’s a really cool piece of work,” says Charles “Chick” Macal, a systems scientist at Argonne National Laboratory who models the spread of diseases but wasn’t involved with this study. “It gets at the underlying question of why these outbreaks occur at all.”

Dean and Schmid say that there’s room to improve their models with more experimental data. They also acknowledge that their study is likely going to stir controversy among plague scholars, some of whom passionately argue that rats caused the medieval outbreaks.

“In plague, there’s a lot of hot debate,” says Dean, who sees herself and Schmid as more objective observers in this case. “We have no dogs in this fight.”

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<p>As the only mammal that can fly, bats were considered enigmatic beings—possibly with nefarious motives—in ancient times. “They resemble much despised rats but with peculiar, clawed wings that enclose their bodies like a dark cape as they hang upside down in trees,” says Mayor.</p>
<p>Pictured: A golden-mantled flying fox <i>(Pteropus pumilus)</i> at the Columbus Zoo</p>

Bats

As the only mammal that can fly, bats were considered enigmatic beings—possibly with nefarious motives—in ancient times. “They resemble much despised rats but with peculiar, clawed wings that enclose their bodies like a dark cape as they hang upside down in trees,” says Mayor.

Pictured: A golden-mantled flying fox (Pteropus pumilus) at the Columbus Zoo

Photograph by Joel Sartore, National Geographic Photo Ark

Plague – Symptoms and causes

Overview

Plague is a serious bacterial infection that’s transmitted primarily by fleas. The organism that causes plague, Yersinia pestis, lives in small rodents found most commonly in rural and semirural areas of Africa, Asia and the United States. The organism is transmitted to humans who are bitten by fleas that have fed on infected rodents or by humans handling infected animals.

Known as the Black Death during medieval times, today plague occurs in fewer than 5,000 people a year worldwide. It can be deadly if not treated promptly with antibiotics. The most common form of plague results in swollen and tender lymph nodes — called buboes — in the groin, armpits or neck. The rarest and deadliest form of plague affects the lungs, and it can be spread from person to person.

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Symptoms

Plague is divided into three main types — bubonic, septicemic and pneumonic — depending on which part of your body is involved. Signs and symptoms vary depending on the type of plague.

Bubonic plague

Bubonic plague is the most common variety of the disease. It’s named after the swollen lymph nodes (buboes) that typically develop in the first week after you become infected. Buboes may be:

• Situated in the groin, armpit or neck
• About the size of a chicken egg
• Tender and firm to the touch

Other bubonic plague signs and symptoms may include:

• Sudden onset of fever and chills
• Headache
• Fatigue or malaise
• Muscle aches

Septicemic plague

Septicemic plague occurs when plague bacteria multiply in your bloodstream. Signs and symptoms include:

• Fever and chills
• Extreme weakness
• Abdominal pain, diarrhea and vomiting
• Bleeding from your mouth, nose or rectum, or under your skin
• Shock
• Blackening and death of tissue (gangrene) in your extremities, most commonly your fingers, toes and nose

Pneumonic plague

Pneumonic plague affects the lungs. It’s the least common variety of plague but the most dangerous, because it can be spread from person to person via cough droplets. Signs and symptoms can begin within a few hours after infection, and may include:

• Cough, with bloody mucus (sputum)
• Difficulty breathing
• Nausea and vomiting
• High fever
• Headache
• Weakness
• Chest pain

Pneumonic plague progresses rapidly and may cause respiratory failure and shock within two days of infection. Pneumonic plague needs to be treated with antibiotics within a day after signs and symptoms first appear, or the infection is likely to be fatal.

When to see a doctor

If you begin to feel ill and have been in an area where plague has been known to occur, seek immediate medical attention. You’ll need treatment with medication to prevent serious complications or death.

In the United States, plague has been transmitted to humans in several western and southwestern states — primarily New Mexico, Arizona, California and Colorado. Worldwide, plague is most common in rural and semirural parts of Africa (especially the African island of Madagascar), South America and Asia.

Causes

The plague bacteria, Yersinia pestis, is transmitted to humans through the bites of fleas that have previously fed on infected animals, such as:

• Rats
• Mice
• Squirrels
• Rabbits
• Prairie dogs
• Chipmunks
• Voles

The bacteria can also enter your body if a break in your skin comes into contact with an infected animal’s blood. Domestic cats and dogs can become infected with plague from flea bites or from eating infected rodents.

Pneumonic plague, which affects the lungs, is spread by inhaling infectious droplets coughed into the air by a sick animal or person.

Risk factors

The risk of developing plague is very low. Worldwide, only a few thousand people develop plague each year. However, your plague risk can be increased depending on the area where you live and travel, your job, and your hobbies.

Location

Plague outbreaks are most common in rural and semirural areas that are overcrowded, have poor sanitation and have a high rodent population. The greatest number of human plague infections occur in Africa, especially the African island of Madagascar. Plague has also been transmitted to humans in parts of Asia and South America.

In the United States, plague is rare, but it has been known to occur in several western and southwestern states — primarily New Mexico, Arizona, California and Colorado.

Job

Veterinarians and their assistants have a higher risk of coming into contact with domestic cats and dogs that may have become infected with plague. People who work outdoors in areas where plague-infected animals are common are also at higher risk of getting plague.

Hobbies

Camping, hunting or hiking in areas where plague-infected animals reside can increase your risk of being bitten by an infected flea.

Complications

Complications of plague may include:

• Death. Most people who receive prompt antibiotic treatment survive bubonic plague. Untreated plague has a high fatality rate.
• Gangrene. Blood clots in the tiny blood vessels of your fingers and toes can disrupt blood flow and cause that tissue to die. The portions of your fingers and toes that have died may need to be removed (amputated).
• Meningitis. Rarely, plague may cause inflammation of the membranes surrounding your brain and spinal cord (meningitis).

Prevention

No effective vaccine is available, but scientists are working to develop one. Antibiotics can help prevent infection if you’re at risk of or have been exposed to plague. Take the following precautions if you live or spend time in areas where plague outbreaks occur:

• Rodent-proof your home. Remove potential nesting areas, such as piles of brush, rock, firewood and junk. Don’t leave pet food in areas that rodents can easily access. If you become aware of a rodent infestation, take steps to control it.
• Keep your pets free of fleas. Ask your veterinarian which flea-control products will work best.
• Wear gloves. When handling potentially infected animals, wear gloves to prevent contact between your skin and harmful bacteria.
• Use insect repellent. Closely supervise your children and pets when spending time outside in areas with large rodent populations. Use insect repellent.

Bubonic Plague: Overview and More

The very idea of the Bubonic Plague is something we associate with the Dark Ages when tens of millions were killed in the wake of the “Black Death” which swept across Asia, Africa, and Europe in the 14th century. Like smallpox and polio, most of us assumed that the plague had become the stuff of history books.

Disease control experts say this is not the case—in fact, they have begun to see a re-emergence of the disease. The first such outbreak took place in 1994 in India, which killed 56 people and hospitalized more than 600. Since then, the plague has been positively identified in the Democratic Republic of Congo (65 deaths in 2005), Madagascar (69 deaths in 2014 and 57 more in 2017), and even parts of the United States (four deaths and 16 infections in 2015).  As late as June 2017, two New Mexico natives were positively diagnosed with the plague, adding to the 600-plus infections expected globally by the year’s end.

Illustration by JR Bee, Verywell

Bubonic Plague Symptoms

When a human is infected with the bacteria called Y. pestis, it travels through the lymphatic system and ends up in the lymph nodes where it causes painful, boil-like enlargements called buboes. This typically happens within one to seven days of exposure and can be accompanied by a number of symptoms including:

• Chills
• High fever
• Extreme exhaustion
• Pain
• Breathing constriction
• Muscle cramps
• Vomiting of blood
• Gangrene of the toes, fingers, lips, and nose
• Opening of swollen buboes (lymph nodes in armpit or groin)
• Seizures

Without treatment, the bubonic plague will result in death in 60 percent to 90 percent of cases, usually within 10 days. With treatment, about 90% of patients survive.

Other Forms

The route of the disease can vary in persons infected by Y. pestis. For instance, rather than traveling from an insect bite to the lymph nodes, the bacteria can enter the body through other routes and cause an entirely different set of symptoms.

• Pneumonic plague occurs when the bacteria is spread to the lungs, usually when an infected person coughs or sneezes on another. While uncommon, it is considered a more serious form of plague, causing the rapid development of pneumonia, chest pains, and bloody or watery sputum, If left untreated, pneumonic plague can cause respiratory failure and death, usually within 36 hours.
• Septicemic plague occurs when the bacteria find its way directly into the bloodstream, often through a crack or sore in the skin. It is the rarest form of the disease and arguably the most aggressive. Symptoms are similar to that of the bubonic plague but can include characteristic bleeding beneath the skin. Death is almost inevitable if treatment is not delivered within 24 hours.

Causes

Bubonic plague is a potentially fatal infection caused by the bacteria Yersinia pestis.

The disease is transmitted by the bite of an infected rat flea (Xenopsylla cheopis) which makes its home on smaller rodents such as rats, field mice, and squirrels.

Since the bacteria is harmless to fleas, it has the perfect vehicle by which to be carried directly from animals to humans. In addition to smaller rodents like chipmunks and prairie dogs, Yersinia pestis has been found in larger mammals including rabbits, opossum, wild coyotes, and even domestic dogs and cat that have come into contact with rodents.

Diagnosis

Bubonic plague is diagnosed by running lab cultures on sputum, blood, spinal fluid, or infected lymph nodes. In parts of the world where the plague is more commonly seen, a rapid dipstick test can usually identify bacterial antigens within 15 minutes. 

Treatment

Due to the clinical severity of the disease, doctors will usually start treatment presumptively while awaiting lab results. Ideally, treatment should be started within 24 hours, usually in the form of intravenous antibiotics such as streptomycin, doxycycline, or tetracycline. If treated in a timely manner, survival rates can range from 85 percent to as high as 99 percent.

Prevention

The key to the prevention of bubonic plague is the avoidance of rodents or any wild animal that can carry fleas. It also requires you to safeguard your property from things that attract animals, like open waste containers or unfenced gardens. There are precautions to take for the prevention of bubonic plague, especially if you live in an area where flea infestations are common.

Tips for the Prevention of Bubonic Plague

• Use a bug repellent spray when outdoors and wear long pants and boots.
• Never handle sick or dead animals. If you must, wear heavy gloves.
• Keep your pets indoors or provide them flea collars.
• Eliminate fleas from your home.

If traveling to parts of the world where outbreaks have occurred (Madagascar, Peru, Democratic Republic of Congo), check travel advisories before departure and bring plenty of insect repellent containing 80 percent DEET. There is currently no vaccine to prevent bubonic plague.

The plague is one of several infectious diseases that were once universally fatal but can now be treated.

While rare, it is important to take precautions to prevent this or any other flea-borne disease, whether it be typhus, tapeworm, or Lyme disease. 

A Word From Verywell

The bubonic plague is commonly associated with the Black Death of the 14th century, but there are many recent cases of the disease on record. It is important to remember, especially if you live in areas with high flea infestations, to take the proper precautions to prevent the disease. Though fatal, the bubonic plague is now very treatable, especially if it is caught early on.

Did bubonic plague really cause the Black Death?

By Debora Mackenzie

THE DISEASE that spread like wildfire through Europe between 1347 and 1351 is still the most violent epidemic in recorded history. It killed at least a third of the population, more than 25 million people. Victims first suffered pain, fever and boils, then swollen lymph nodes and blotches on the skin. After that they vomited blood and died within three days. The survivors called it the Great Pestilence. Victorian scientists dubbed it the Black Death.

As far as most people are concerned, the Black Death was bubonic plague, Yersinia pestis, a flea-borne bacterial disease of rodents that jumped to humans. But two epidemiologists from Liverpool University say we’ve got it all wrong. In Biology of Plagues, a book released earlier this year, they effectively demolish the bubonic plague theory. “If you look at how the Black Death spread,” says Susan Scott, one of the authors, “one of the least likely diseases to have caused it is bubonic plague.” If Scott and co-author Christopher Duncan are right, the world would do well to listen.

Whatever pathogen caused the Black Death appears to have ravaged Europe several times during the past two millennia, and it could resurface again. If we knew what it really was, we could prepare for it. “It’s always important to re-evaluate these questions so we are not taken by surprise,” says Steve Morse, an expert on emerging viral diseases at Columbia University in New York. Yet few experts in infectious diseases have even read the book, let alone taken its ideas seriously. New Scientist has, and it looks to us as though Scott and Duncan are on to something.

The idea that the Black Death was bubonic plague dates back to the late 19th century, when Alexandre Yersin, a French bacteriologist, unravelled the complex biology of bubonic plague. He noted that the disease shared a key feature with the Black Death&colon; the bubo, a dark, painful, swollen lymph gland usually in the armpit or groin. Even though buboes also occur in other diseases, he decided the two were the same, even naming the bacterium pestis after the Great Pestilence.

But the theory is riddled with glaring flaws, say Scott and Duncan. First of all, bubonic plague is intimately associated with rodents and the fleas they carry. But the Black Death’s pattern of spread doesn’t fit a rat and flea-borne disease. It raced across the Alps and through northern Europe at temperatures too cold for fleas to hatch, and swept from Marseilles to Paris at four kilometres a day – -far faster than a rat could travel. Moreover, the rats necessary to spread the disease simply were not there. The only rat in Europe in the Middle Ages was the black rat, Rattus rattus, which stays close to human habitation. Yet the Black Death jumped across great tracts of open country-up to 300 kilometres between towns in France-in only a few days with no intermediate outbreaks. “Iceland had no rats at all,” notes Duncan, “but the Black Death was reported there too.”

In contrast, bubonic plague spreads, as rats do, slowly and sporadically. In 1907, the British Plague Commission in India reported an outbreak that took six months to move 300 feet. After bubonic plague arrived in South Africa in 1899, it moved inland at just 20 kilometres a year, even with steam trains to help.

The disease that caused the Black Death stayed in Europe until 1666. During its 300-year reign, Scott and Duncan have found records of outbreaks that occurred somewhere in France virtually every year. Every few years, these outbreaks spawned epidemics that ravaged the rest of Europe. For Yersinia to do this, it would have to become established in a population of rodents that are resistant to the disease. It couldn’t have been rats, because the plague bacterium kills them-along with all other European rodents. As a result, Europe, along with Australia and Antarctica, remain the only regions of the world where bubonic plague has never settled. So, once again, the Black Death behaved in a way plague simply cannot.

Nor is bubonic plague contagious enough to have been the Black Death. The Black Death killed at least a third of the population wherever it hit, sometimes more. But when bubonic plague hit India in the 19th century, fewer than 2 per cent of the people in affected towns died. And when plague invaded southern Africa, South America and the south-western US, it didn’t trigger a massive epidemic.

The most obvious problem with the plague theory is that, unlike bubonic plague, the Black Death obviously spread directly from person to person. People in the thick of the epidemic recognised this, and Scott and Duncan proved they were right by tracing the anatomy of outbreaks, person by person, using English burial records from the 16th century. These records, which detail all deaths from the pestilence by order of Elizabeth I, clearly show the disease spreading from one person to their neighbours and relatives, separated by an incubation period of 20 to 30 days.

The details tally perfectly with a disease that kills about 37 days after infection. For the first 10 to 12 days, you weren’t infectious. Then for 20 to 22 days, you were. You only knew you were infected when you fell ill, for the final five days or less-but by then you had been infecting people unknowingly for weeks. Europeans at the time clearly knew the disease had a long, infectious incubation period, because they rapidly imposed measures to isolate potential carriers. For example, they stopped anyone arriving on a ship from disembarking for 40 days, or quarantina in Italian – -the origin of the word quarantine.

Telltale timing

Epidemiologists know that diseases with a long incubation time create outbreaks that last months. From 14th-century ecclesiastical records, Scott and Duncan estimate that outbreaks of the Black Death in a given town or diocese typically lasted 8 or 9 months. That, plus the delay between waves of cases, is the fingerprint of the disease across Europe over seasons and centuries, they say. The pair found exactly the same pattern in 17th-century outbreaks in Florence, Milan and a dozen towns across England, including London, Colchester, Newcastle, Manchester and Eyam in Derbyshire. In 1665, the inhabitants of Eyam selflessly confined themselves to the village. A third of them died, but they kept the disease from reaching other towns. This would not have worked if the carriers were rats.

Despite the force of their argument, Scott and Duncan have yet to convince their colleagues. None of the experts that New Scientist spoke to had read their book, and a summary of its ideas provoked reactions that range from polite interest to outright dismissal. Some of Scott’s colleagues, for example, have scoffed that “everyone knows the Black Death was bubonic plague”.

“I doubt you can say plague was not involved in the Black Death, though there may have been other diseases too,” says Elisabeth Carniel, a bubonic plague expert at the Pasteur Institute in Paris. “But I haven’t had time to read the book.” Carniel suggests that fleas could have spread the Black Death directly between people. Human fleas can keep it in their guts for a few weeks, leading to a delay in spread. But this would be unlikely to have happened the same way every time.

Moreover, people with enough Yersinia in their blood for a flea to pick it up are already very sick. They would only be able to pass their infection on in this way for a very short time-and whoever the flea bit would also sicken within a week, the incubation time of Yersinia. This does not fit the pattern documented by Scott and Duncan. Neither would an extra-virulent Yersinia, which would still depend on rats.

There have been several other ingenious attempts to save the Yersinia theory as inconsistencies have emerged. Many fall back on pneumonic plague, a variant form of Yersinia infection. This can occur in the later stages of bubonic plague, when the bacteria sometimes proliferate in the lungs and can be coughed out, and inhaled by people nearby. Untreated pneumonic plague is invariably fatal and can spread directly from person to person.

But not far, and not for long-plague only becomes pneumonic when the patient is practically at death’s door. “It is simply impossible that people sick enough to have developed the pneumonic form of the disease could have travelled far,” says Scott. Yet the Black Death typically jumped between towns in the time a healthy human took to travel. Also, pneumonic plague kills quickly-within six days, usually less. With such a short infectious period, local outbreaks of pneumonic plague end much sooner than 8 or 9 months, notes Scott. Rats and fleas can restart them, but then the disease is back to spreading slowly and sporadically like flea-borne diseases. Moreover, pneumonic plague lacks the one thing that links Yersinia to the Black Death&colon; buboes.

If the Black Death wasn’t bubonic plague, then what was it? Possibly-and ominously-it may have been a virus. The evidence comes from a mutant protein on the surface of certain white blood cells. The protein, CCR5, normally acts as a receptor for the immune signalling molecules called chemokines, which help control inflammation. The AIDS virus and the poxvirus that causes myxomatosis in rabbits also use CCR5 as a docking port to enter and kill immune cells.

In 1998, a team led by Stephen O’Brien of the US National Cancer Institute analysed a mutant form of CCR5 that gives some protection against HIV. From its pattern of occurrence in the population, they think it arose in north-eastern Europe some 2000 years ago-and around 700 years ago, something happened to boost its incidence from 1 in 40,000 Europeans to 1 in 5. “It had to have been a breathtaking selective pressure to jack it up that high,” says O’Brien. The only plausible explanation, he thinks, is that the mutation helped its carriers survive the Black Death. In fact, say Scott and Duncan, Europeans did seem to grow more resistant to the disease between the 14th and 17th centuries.

Yersinia, too, enters and kills immune cells when it causes disease. But when O’Brien’s team pitted Yersinia against blood cells from people with and without the mutation, they found no dramatic difference. “The results were equivocal,” says O’Brien. “We don’t know if the mutation protected or not.” Further experiments are under way. Similar mutations occur elsewhere in the world, but at nowhere near the high frequency of the European mutant. This suggests that pathogens such as smallpox exerted some selective force, but nothing like whatever happened in Europe, says O’Brien.

The association between CCR5 and viruses suggests that the Black Death was a virus too. Its sudden emergence, and equally sudden disappearance after the Great Plague of London in 1666, also argue for a viral cause. Like the deadly flu of 1918, viruses can sometimes mutate into killers, and then disappear.

But what sort of virus was the Black Death? Scott and Duncan suggest a haemorrhagic filovirus such as Ebola, since the one consistent symptom was bleeding. In fact they think “haemorrhagic plague” would be a good new name for the disease.

They are not the first to blame Ebola for an ancient plague. Scientists and classicists in San Diego reported in 1996 that the symptoms of the plague of Athens around 430 BC, described by Thucydides, are remarkably similar to Ebola, including a distinctive retching or hiccupping. Apart from that, many of the symptoms of that plague- – and one in Constantinople in AD 540 – -were similar to the Black Death.

Of course, the filoviruses we know about are relatively hard to catch, with an incubation period of a week or less, not three weeks or more. But there are other haemorrhagic viruses&colon; Lassa fever in Africa is fairly contagious, and incubates for up to three weeks. Eurasian hantaviruses can incubate for up to 42 days, but are not usually directly contagious between people. Both can be as deadly as the Black Death.

Out of Africa

Perhaps we can narrow the search to Africa. Europeans first recorded the Black Death in Sicily in 1347. The Sicilians blamed it on Genoese galleys that arrived from Crimea just as the illness exploded. But the long incubation period means the infection must have arrived earlier. Scott suspects it initially came from Africa, just a short hop away from Sicily. That continent is historically the home of more human pathogens than any other, and the people who lived through the epidemics that wracked Athens and Constantinople said their disease came from there. The epidemic in Constantinople, for instance, seems to have come via trade routes from the Central African interior. “And I’m sure that disease was the same as the Black Death,” says O’Brien.

One way to solve the puzzle could be to look for the pathogen’s DNA in the plague pits of Europe. Didier Raoult and colleagues at the University of the Mediterranean in Marseilles examined three skeletons in a 14th-century mass grave in Montpellier last year (New Scientist, 11 November 2000, p 31). They searched the skeletons for fragments of DNA unique to several known pathogens-Yersinia, anthrax or typhus. They found one match&colon; Yersinia. In their report they wrote&colon; “We believe that we can end the controversy. Medieval Black Death was [bubonic] plague.”

Not so fast, says Scott. Southern France probably had bubonic plague at that time, even if it wasn’t the Black Death. Moreover, attempts by Alan Cooper, director of the Ancient Biomolecules Centre at Oxford University, and Raoult’s team to replicate the results have so far failed, says Cooper. Similar attempts to find Yersinia DNA at mass graves in London, Copenhagen and another burial in southern France have also failed.

It’s too early to conclude that the failure to find Yersinia DNA means the bacterium wasn’t there, though. The art of retrieving ancient DNA is still in its infancy, Cooper warns. Pathogen DNA – -especially that of fragile viruses – -is extremely difficult to reliably identify in remains that are centuries old. “The pathogen decays along with its victim,” he says. Scientists have had difficulty, for example, in retrieving the 1918 flu virus, even from bodies less than a century old and preserved by permafrost. And even if the technique for retrieving ancient DNA improves, you need to know what you’re searching for. There is no way now to search for an unknown haemorrhagic virus.

But the possibility that the Black Death could strike again should give scientists the incentive to keep trying. The similarity of the catastrophes in Athens, Constantinople and medieval Europe suggests that whatever the pathogen is, it comes out of hiding every few centuries. And the last outbreak was its fastest and most murderous. What would it do in the modern world? Maybe we should find it, before it finds us.

• Further reading&colon;Biology of plagues&colon; Evidence from historical populationsby Susan Scott and Christopher Duncan, Cambridge University Press (2001)

More on these topics:

1320: Section 6: The Black Death

What You Need to Know

For many, the Bubonic Plague sounds like something out of ancient history. For some California residents, though, it’s become a modern reality. 

On August 20 of this year, state officials announced that a person in the South Lake Tahoe area had contracted the Plague – the state’s first case of the disease in five years. Spread by rodents, especially the ground squirrel, the Plague presents a genuine health risk for California residents and their families.

While the presence of the Bubonic Plague in ground squirrels in California is frightening, Smith’s Pest Management can help decrease your risk of coming into contact with the disease. Offering comprehensive pest control services, we help property owners across the San Francisco Bay Area protect their homes.

Today, we’re sharing some background on the relationship between ground squirrels and the plague, and some professional tips to keep the disease away from your family and household.

Let’s dive in.

Bubonic Plague in California in 2020: An Overview

The Bubonic Plague, also known as Black Death, originated in Asia roughly 2,000 years ago, where it spread on trading ships. The disease first made its way to Europe around 1347, when 12 ships full of infected sailors from the Black Sea docked in Sicily. 

Over the next five years, the disease killed more than 25 million people throughout Europe – roughly a third of the continent’s population. 

Eventually, scientists discovered that the Bubonic Plague spreads from person to person via respiratory droplets or through the bite of infected fleas and rodents. 

While the Plague is rare in humans, it does still exist in rodents, which is how it’s made its way to California today. 

According to the Los Angeles Department of Public Health:

“Today, wild rodents in rural areas are the principal source of plague in Los Angeles county…Since 1979 there have been three cases of human plague contracted within the county. Two cases were the result of contact with infected rodent fleas.”

As it stands now, the Plague is common in several California regions: primarily the foothills, mountains, and coast of the state. It is absent from the Central Valley and the Southeastern desert regions. 

While various rodents can spread the Plague, the ground squirrel is the most common carrier. 

Ground Squirrel Diseases 

While some people think they look cute from afar, ground squirrels in California can carry many infectious diseases and are primarily responsible for the Bubonic Plague’s current outbreak in California. 

According to the University of California’s Agriculture and Natural Resources department:

“Ground squirrels are associated with the spread of Rocky Mountain spotted fever, rat bite fever, tularemia, Chagas’ disease, adiospiromycosis, and encephalomyocarditis. Notably, they can serve as reservoirs for sylvatic (bubonic) plague, a highly infectious disease caused by the bacteria Yersinia pestis…People and their pets can get plague if they visit or live in areas where ground squirrels or other rodents are infected.” 

For people who want to avoid coming into contact with Bubonic Plague, limiting exposure to ground squirrels is critical.

How Does a Squirrel Get Bubonic Plague?

Like many diseases, the Plague occurs naturally throughout the Western United States. It is especially common in Arizona, California, Colorado, Utah, and New Mexico. The bacteria that causes the plague (Yersinia pestis) begins its transmission cycle with fleas. 

According to the Centers for Disease Control and Prevention (CDC), ground squirrels contract the disease when an infected flea bites them. Over time, the disease kills the infected squirrel, causing the hungry fleas to abandon the dead animal and seek another host – typically another squirrel or rodent, or even a house pet. The disease continues to spread in this way. 

Am I At Risk of Getting the Plague? 

Humans can contract the Plague from affected animals. When the Plague starts affecting large numbers of its primary hosts (ground squirrels, in this case) and begins to impact other species, such as cats and dogs, it’s known as an epizootic. According to the CDC, humans are usually more at risk of contracting the Plague during, or shortly after, a plague epizootic. 

The Plague bacteria can be transmitted to humans in the following ways:

• A bite from an infected flea.
• Contact with contaminated tissues or fluids (common in hunters who may come into contact with infected animals, for example).
• Contact with infectious droplets from a person or an infected animal, although this type of spread has not been documented in the United States since 1924.
• Pet involvement, such as when a house cat comes into contact with an infected squirrel.

What Are the Symptoms of the Plague?

While there are effective treatments for the Bubonic Plague in humans, it is a horrendous disease by all accounts. Symptoms include:

• Fever
• Chills
• Muscle aches
• Weakness
• Swollen and tender lymph nodes 

The incubation period for the Plague is about 2-6 days. The disease is highly curable when diagnosed early. If the Plague is not treated in time, it can become more severe – leading to a life-threatening blood infection or pneumonia. 

How Can I Protect Myself and My Family from the Plague?

Despite the current outbreak of Bubonic Plague in ground squirrels in California, there are many ways to protect yourself and your home. Follow these tips:

• Keep free-roaming cats indoors. If you cannot stop an animal from free-roaming, take steps to minimize their contact with rodents and fleas. Putting a bell on your cat’s collar is a good option. Talk to your vet about protecting your free-roaming cat with oral or topical flea control. Finally, be careful when handling the pet. Avoid close face-to-face contact with free-roaming cats and have the animal evaluated by a veterinarian.
• Avoid contact with rodents and their fleas. If you find a sick or dead rodent, do not touch it. Instead, report the rodent to local rangers and health authorities.
• Control rodent populations around your home and outbuildings. Prevent rodents from entering buildings by removing access to food or shelter (as much as possible). For best results, work with a professional company like Smith’s Pest Management, which offers effective ground squirrel control services.
• Be careful during recreational activities. Avoid camping, sleeping, or resting near animal burrows. Avoid feeding rodents and be sure to store all food in rodent-proof bins. If you’re hiking in a Plague area, dress in long pants, tucked into boots. This will help reduce your exposure to fleas. 

Dealing with Ground Squirrels in the San Francisco Bay Area? We’re Here to Help!

We understand that the recent Plague outbreak is frightening for California families. Fortunately, our team is here to help. Specializing in pest control for residential and commercial properties, Smith’s Pest Management will decrease ground squirrel populations around your home with ground squirrel control services, to help limit possible exposure to the Plague bacteria. We offer local, family-owned, eco-conscious services and creative pest control solutions for every pest management issue. 

Smith’s Pest Management also works with parks and large facilities to eradicate ground squirrels. Contact us today to learn more or to request a quote!

Disclaimer: The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

90,000 How are we treated for bubonic plague

There is also a vaccine against plague, and not even one. Among them there are those based on live weakened bacteria, on killed ones or on the bacterial F1 protein. The organization also reviewed vaccines, but the authors did not find convincing evidence of effectiveness or comparison of different options among themselves for 1998.

Indicator.Ru recommends: stay away from fleas and rodents, treat with antibiotics

Plague is easier to prevent than to cure.To avoid the disease, you need to avoid contact with animals that often carry it, do not eat rodent meat and beware of fleas. Plague vaccines are not available on the open market: there is no point in using them even for travelers. Vaccination is recommended only for experimenters working with the plague bacillus in the laboratory, as well as for those who are sent to the field in those rare parts of the world where infection is still rampant (for example, in the Congo) and where it will not be possible to protect themselves from mammals. vectors and fleas.

It is important to understand that many treatment options are approved based on animal treatment publications or in small groups of people. However, the result in such trials is pretty obvious: if successful, a high percentage of the sick will survive. This reduces the risk of subjective interpretation. Survival, as well as the results of laboratory tests, are fairly clear and relatively objective indicators (as opposed to, for example, the results of a survey about well-being). The task is also complicated by the fact that at a low incidence rate, it is difficult to make a large sample for research.Therefore, randomized controlled trials are extremely rare.

However, like many bacterial infections, the plague bacterium is killed by antibiotics, and resistant (resistant) strains are very rare. The chances are especially high for those patients who start treatment immediately after the first symptoms appear. Most often, chloramphenicol, tetracycline, streptomycin are used for this purpose. Newer generations of antibiotics, like doxycycline and gentamicin, have also been shown to be effective (albeit in very limited patient populations).It is comforting, perhaps, that these drugs have already been studied in the fight against other bacteria, and therefore some sudden and rare side effects, most likely, will not be found.

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Bubonic plague: what to fear and how not to get infected. Dossier – Biographies and information

TASS-DOSSIER.Plague (or plague disease) is a serious infectious disease. The causative agent is the plague stick (lat.Yersinia Pestis; was discovered in 1894). This bacterium is usually found on small animals (rodents) and on the parasites that live on them – fleas. It is transmitted to humans through the bite of an infected flea, through direct contact with infected materials, and also by airborne droplets from an infected one. If untreated, it can lead to serious consequences, including human death (mortality ranges from 30% to 60%).

Signs and Symptoms

The incubation period lasts 3-7 days. Then the infected person usually develops symptoms typical of the flu: sudden fever, chills, headache and body aches, as well as weakness, nausea and vomiting.

Forms of the disease

Depending on the route of infection, there are three forms of plague disease: bubonic, septic and pulmonary.

Bubonic is the most common form of plague. Caused by the bite of an infected flea.The plague bacillus, once in the human body, affects the lymphatic system. As a result of its multiplication, the lymph node becomes hard, a bubo appears on the body. In the late stage of the disease, inflamed lymph nodes can turn into open, festering wounds, and the plague can spread through the blood to other organs.

Septic form can occur with flea bites or direct contact with infected materials (for example, bandages from patients with bubonic plague), when the infection penetrates through cracks in the skin and enters the bloodstream immediately without forming buboes.

Pulmonary – the most severe and least common form of plague, accompanied by damage to the respiratory system. Most often occurs in a patient with bubonic plague, which is in a late stage. It can be transmitted by airborne droplets.

Diagnostics and treatment

It is important to diagnose the plague disease in time. This can be done in a laboratory way by examining samples of materials taken from bubo fluid, blood or sputum for the presence of plague bacillus (Y.Pestis).

Antibiotic treatment and supportive therapy are effective in the fight against plague. If untreated, plague disease can be fatal in a short time.

Prevention and vaccination

Prevention consists primarily in informing the population about foci of the spread of plague among animals. In this case, it is recommended to beware of flea bites and not to touch animal corpses. You should also avoid direct contact with infected tissues, avoid contact with patients suffering from pneumonic plague.

Foci of the spread of plague among animals

The prevalence of plague coincides with the geographic distribution of rodents that inhabit all continents except Australia.

In Asia and on the territory of Russia, the natural carriers of plague are gerbils and marmots.

Disease statistics

In the past, plague has caused widespread pandemics with high mortality rates. In the XIV century, one of the forms of the plague, known as the “Black Death”, claimed the lives of 50 million people in the “old world”: as a result, a quarter of the population of Europe died.

According to the World Health Organization (WHO), in the world in 2010-2015, 3,248 cases of plague of various forms were registered, 584 people died from the disease.

Total in 2010-2015 outbreaks of plague occurred in 11 countries: China, the Democratic Republic of the Congo, Uganda, Tanzania, Madagascar, the United States, Peru, Bolivia, Kyrgyzstan, Kazakhstan, and Russia. The largest number of cases and deaths was noted in Madagascar (2 thousand 404 cases, 476 deaths) and in the Democratic Republic of the Congo (586 cases, 67 deaths).

In Russia, from 1961 to 2014, the plague was never recorded. In 2014, a marmot hunter fell ill with the bubonic plague in the Kosh-Agach region of the Altai Republic, his life was saved. In 2015, a similar incident occurred in the same area. Both hunters became infected by butchering killed animals.

Science: Science and technology: Lenta.ru

Plague has firmly entered the history and culture of mankind as a monstrous disease from which no one could escape – not even the doctors themselves.Pestilence infiltrated homes, exterminated families, cities filled with thousands of corpses. Now mankind knows the causes of the disease and how to treat it, but in the past, healers were powerless in the face of the Plague. Neither knowledge of astrology, nor the study of ancient treatises written by ancient authorities helped. “Lenta.ru” talks about plague pandemics and how they made mankind think about the real nature of infections.

Plague is one of the most ancient diseases. Traces of its pathogen – Yersinia pestis – were found in the teeth of people who lived five thousand years ago, in the Bronze Age.This bacterium has caused two of the deadliest pandemics in human history, killing several hundred million people. The disease spread like a fire, destroying entire cities, and doctors could not oppose it – largely due to prejudice and low level of medical knowledge. Only the invention of antibiotics and vaccines allowed mankind to overcome the plague, although its outbreaks still occur in various parts of the world, even in developed countries.

The disease begins like a cold or flu: the temperature rises, weakness and headache occur.The person does not even suspect that the cause of his illness was an invisible bacteriological bomb – a flea, whose insides are stuffed with a plague stick. The insect is forced to regurgitate the absorbed blood back into the wound, and a whole army of deadly bacteria enters the body. If they penetrate the lymph nodes, then the patient develops a bubonic form of the disease. The nodes swell up a lot. In the Middle Ages, they were burned and pierced – to the detriment of the patient himself and those who were nearby.

Plague bacillus

The septic form of the plague occurs when the plague bacillus enters the bloodstream, causing its intravascular coagulation.Clots disrupt tissue nutrition, and non-clotted blood, penetrating the skin, causes a characteristic black rash. According to one version, it was because of the blackening of the skin that the plague pandemic in the Middle Ages was called the Black Death. Septic plague is less common than other forms, but in the past, mortality from it reached almost one hundred percent – antibiotics were not yet known at that time.

Finally, the pneumonic form of the plague is what distinguished the Black Death. During the first pandemic, the Justinian plague, there was almost no mention of hemoptysis, but in the Middle Ages this symptom was as common as buboes.The bacteria entered the lungs and caused pneumonia, and the patient exhaled the plague bacillus, which got into the respiratory organs of other people. During the Black Death, the disease was transmitted from person to person and did not need fleas as vectors.

The ingestion of a pathogen in the lungs in the past almost always meant certain death – without adequate antibiotic treatment, a person died in two to three days. It is the pulmonary form that is responsible for the death of tens of millions of people in the XIV century

Three major plague pandemics are known.The Justinian Plague, which began in 541 AD, killed about one hundred million people worldwide over two centuries and wiped out half of Europe’s population. The Black Death, the second wave of the disease, raged for two decades and claimed the lives of an estimated one to two hundred million people, making it the deadliest non-viral pandemic in human history. The third pandemic, which began in China and lasted for about a century (from 1855 to 1960), killed more than ten million people.

A flea with intestines clogged with a plague bacillus

The history of the plague began ten thousand years ago, when the relatively harmless soil bacterium Yersinia pseudotuberculosis , which causes only mild gastrointestinal upset, acquired several mutations that allowed it to colonize human lungs. Then the changes in the Pla gene made the bacterium extremely toxic: it learned to break down proteins in the lungs and multiply throughout the body through the lymphatic system, forming buboes.These same mutations gave her the ability to be transmitted by airborne droplets. As in many cases, epidemics are caused by close contact between humans and wildlife.

About four thousand years ago, mutations occurred that made Yersinia pestis highly virulent, capable of being transmitted by fleas through rodents, humans and other mammals. The blood-sucking insects parasitizing on mammals traveled long distances with the travelers. Fleas were taken into luggage and merchant goods, so the development of trade was one of the causes of the pandemic.The Justinian plague originated in Central Asia, but first penetrated through trade channels to Africa, and from there reached Byzantine Constantinople – a densely populated city and world center of the first millennium AD. The bubonic and septic forms of the disease at the peak of the epidemic killed five thousand inhabitants a day.

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Dirty killer

How a harmless microbe has killed millions of people around the world for centuries

The Black Death was caused by another strain of the plague bacillus, which is not a direct descendant of the causative agent of Justinian’s plague.It is believed that one of the impulses of the pandemic was the Mongol conquests in the 13th century, which caused a decline in trade and agriculture, and then famine. Climatic changes also played a role, when prolonged droughts led to mass migration of rodents, including marmots, closer to human settlements. Due to the crowding of animals, an epizootic arose – an analogue of an epidemic in animals.

Since marmot meat was considered a delicacy, the spread of the disease among people was a matter of time.

Plague first struck Asia, the Middle East, Africa, and with merchant ships penetrated Europe, where it killed an estimated 34 million people

The third pandemic began with an outbreak of the bubonic plague in China in 1855, after which the infection spread to all continents except Antarctica. The natural focus was in the Yunnan province, which still carries an epidemiological threat. In the second half of the 19th century, the Chinese began to settle in the area in order to increase the extraction of minerals for which there was a high demand.But this led to close contact of people with yellow-chested rats, which were inhabited by plague-infected fleas. The growth of the urban population and the emergence of congested transport routes opened the way for the bubonic plague. From Hong Kong, the plague spread to British India, where it claimed the lives of one million people, and over the next thirty years – 12.5 million.

Mass Burial of Victims of the Black Death

As with other pandemics, the prevailing misconceptions about the nature of infectious diseases contributed to the spread of the plague.For medieval doctors, the authority of the ancient thinkers Hippocrates and Aristotle was undeniable, and a thorough study of their works was mandatory for all those who were going to connect their lives with medicine.

According to the principles of Hippocrates, disease occurs due to natural factors and human lifestyle. At one time, this thought was generally advanced, since before Hippocrates, diseases were usually considered the result of the intervention of supernatural forces. However, the ancient Greek doctor had scant knowledge of human anatomy and physiology, so he believed that in order for the patient to recover, it was necessary to properly care for him so that the body could cope with the disease itself.

University-educated medieval doctors were the least experienced in the treatment of disease, but had high status and authority. They did not know much about anatomy, and they considered surgery a dirty trade. Religious authorities opposed autopsies, so there were very few universities in Europe that paid attention to the structure of the human body. The fundamental medical principle was the humor theory, according to which human health depended on the balance of four fluids: blood, lymph, yellow bile and black bile.

Painting by Pieter Bruegel the Elder “The Triumph of Death”

Most medieval theoretical physicians believed in Aristotle’s principle that the plague was caused by miasms – vapors that make the air “bad”. Some believed that miasms were formed due to the unfavorable location of celestial bodies, others blamed earthquakes, wind from swamps, disgusting smells of manure and decaying corpses. One of the medical treatises of 1365 stated that the plague cannot be cured without knowledge of humoral theory and astrology, which are very important for the practicing physician.

All preventive measures to combat the plague were reduced to the elimination of the poisonous air that allegedly came from the south. Doctors recommended building houses with windows to the north. It was also necessary to avoid the sea coasts, because the fact that outbreaks of plague began in port cities did not escape the attention of medical authorities. Only they could not even imagine that the disease was spreading through trade routes, and not hovering in the sea air. In order not to get sick with the plague, supposedly you need to hold your breath, breathe through fabric, or burn aromatic herbs.Perfumes, precious stones and metals such as gold were used against the disease.

The buboes were believed to contain plague poison that must be removed. They pierced them, burned them, applied an ointment sucking out the poison, but at the same time bacteria were released that could infect others. Despite the fact that the doctors took, as they thought, all the necessary protective measures, many of them died. Others, realizing that their treatment was ineffective, followed their own advice and fled from the cities, although the plague overtook them at a distance from the centers.Despite the fact that the plague demonstrated the complete impotence of medieval medicine, doctors did not soon overcome their dependence on ancient authorities and moved on to their own observation and experience.

Plague Doctor

One of the few effective methods (albeit with varying success) was quarantine, despite the constant protests of freedom-loving citizens and merchants. In Venice, a delay was established for the entry of ships into the port, which lasted 40 days (the word “quarantine” comes from the Italian quaranta giorni – “forty days”).A similar measure was introduced for people who arrived from plague-infected areas. City councils began hiring doctors – plague doctors – specifically to treat the disease, after which they also went into quarantine.

As many leading theorists died in the pandemic, the discipline was open to new ideas. University medicine failed, so people began to turn to medical practitioners more. With the development of surgery, more and more attention was paid to the direct study of the human body.Medical treatises began to be translated from Latin into languages ​​accessible to a wide audience, which stimulated the revision and development of ideas.

Overall, the pandemic contributed to the development of health systems

The true cause of the plague – Yersinia pestis – was discovered only a few centuries after the Black Death. This was helped by the dissemination among scientists of the advanced ideas of Louis Pasteur, in the 19th century, which turned the views on the causes of many diseases. The scientist, who became the founder of microbiology, was able to prove that infectious diseases are caused by microorganisms, and not by miasms and disturbances in the balance of the body, as contemporaries continued to think, including his teacher and colleague Claude Bernard.Pasteur developed methods of treatment against anthrax, cholera and rabies and founded the Pasteur Institute, which from now on became a center for the fight against dangerous infections.

Plague

Newsletter
October 2017

Key Facts:

• Plague is caused by Yersinia pestis, a zoonotic bacterium commonly found in small mammals and fleas that live on them.
• In a person infected with Yersinia pestis, the incubation period before symptoms develop is 1-7 days.
• There are two main clinical forms of plague infection: bubonic and pulmonary. The most common form is bubonic plague, which is characterized by painful, swollen lymph nodes, or “buboes”.
• Plague is transmitted from animals to humans through the bite of an infected flea, direct contact with infected tissues and airborne droplets.
• Plague in humans can manifest itself as a very serious disease. The fatality rate of bubonic plague reaches 30% -60%, and pneumonic plague, if untreated, is always fatal.
• Plague is successfully treated with antibiotics, so early diagnosis and early treatment can save lives.
• In 2010-2015 worldwide, there were 3,248 cases of plague, including 584 deaths.
• Currently, the three most endemic countries are the Democratic Republic of the Congo, Madagascar and Peru.

Plague disease is caused by the zoonotic bacterium Yersinia pestis, commonly found in small mammals and the fleas that inhabit them.Fleas spread the infection between animals. Human infection can occur as a result of:

• The bite of an infected flea – a carrier of the disease;
• Unprotected contact with infected body fluids or contaminated materials;
• Inhalation of infected small particles / fine droplets exhaled by a patient with pneumonic plague (airborne droplets).

In humans, plague, especially its septic (as a result of bacteria entering the bloodstream) and pulmonary forms, without treatment can be a very serious disease with a lethality rate of 30-100%.Without early initiation of treatment, the pulmonary form is always fatal. It is especially contagious in nature and can cause severe epidemics, transmitted from person to person by airborne droplets.

In 2010-2015 worldwide, there were 3,248 cases of plague, including 584 deaths.

In the past, plague has caused widespread pandemics with high mortality rates. In the 14th century, the plague was known as the Black Death and killed an estimated 50 million people in Europe.Today, plague is easily treatable with antibiotics, and infection prevention is easy, provided standard precautions are followed.

Signs and symptoms.

A person infected with plague usually develops an acute febrile state after an incubation period of 1 to 7 days. Typical symptoms are sudden fever, chills, headache and body aches, as well as weakness, nausea, and vomiting.

There are three forms of plague, depending on the route of infection: bubonic, septic and pulmonary.

• Bubonic plague is the most common form of plague, which is infected by the bite of an infected flea. The causative agent of the plague, the Yersinia pestis bacterium, enters the human body at the site of the bite and moves through the lymphatic system to the nearest lymph node, where it begins to multiply. The lymph node becomes inflamed, swollen and painful. These lymph nodes are called “buboes”. At a later stage of the infection, the inflamed lymph nodes can develop into open, purulent wounds.
• Septic plague develops when an infection enters the bloodstream as a result of advanced bubonic or pneumonic plague, or is the first symptom of Y. pestis infection. It can cause bleeding, tissue necrosis (blackening) and shock.
• Pneumonic plague is the most virulent form of the disease. The incubation period can be extremely short, up to 24 hours. As a rule, pneumonic plague develops in the late stages of bubonic plague as a result of the spread of the infection to the lungs.At the same time, a person with developed pneumonic plague can transmit the infection to others by airborne droplets. If left untreated, pneumonic plague can be fatal.

Where is the plague found?

As an animal disease, plague is found everywhere, with the exception of Oceania. The risk of contracting human plague arises when an isolated human population lives in an area where a natural focus of plague is present (i.e., bacteria, animal reservoirs and vectors are present).

Plague epidemics have occurred in Africa, Asia and South America, but since the 1990s, most human cases of plague have occurred in Africa. The three most endemic countries are Madagascar, Democratic Republic of the Congo and Peru. In Madagascar, cases of bubonic plague are recorded almost every year during the epidemic season (September-April).

Plague diagnostics.

Laboratory testing is required to confirm the diagnosis of plague. Isolation of Y is an exemplary method for confirming the presence of plague in a patient.pestis from a pus sample from a bubo, a blood sample, or a sputum sample. There are different methods for detecting the specific antigen of Y. pestis. One of these is a laboratory validated rapid test using a test strip. This method is now widely used in Africa and South America with the support of WHO.

Treatment.

If untreated, plague can lead to rapid death, therefore rapid diagnosis and early treatment are essential for patient survival and prevention of complications.With timely diagnosis, plague is successfully treated with antibacterial drugs and supportive therapy. Untreated pneumonic plague can be fatal 18-24 hours after symptoms start, but conventional antibiotics for diseases caused by enterobacteriaceae (gram-negative bacilli) can effectively cure the plague if treatment is started early.

Prevention.

Preventive measures include informing the public about the presence of zoonotic plague in their area of ​​residence and disseminating recommendations on the need to protect themselves from flea bites and not to touch the corpses of dead animals.In general, it should be advised to avoid direct contact with infected body fluids and tissues. Standard precautions should be followed when handling potentially infectious patients and collecting specimens for testing.

Vaccination.

WHO does not recommend vaccination of the public, except for high-risk groups (for example, laboratory workers, who are constantly at risk of infection, and health workers).

Fight against plague outbreaks.

• Detection and neutralization of the source of infection: identification of the most probable source of infection in the area where the case (s) of human disease is detected, paying particular attention to the places where the carcasses of small animals accumulate. Conducting appropriate infection control measures. Avoid killing rodents before killing fleas that carry the infection, as fleas will move from a dead rodent to a new host and the infection will continue to spread.
• Healthcare of healthcare workers: informing and training healthcare workers on infection prevention and control measures.Workers in direct contact with persons with pneumonic plague should wear personal protective equipment and receive antibiotics as chemoprophylaxis for seven days, or at least for the time they are at risk of working with infected patients.
• Ensuring the right treatment: Ensuring that patients receive adequate antibiotic treatment and that there is an adequate supply of antibiotics.
• Isolation of patients with pneumonic plague: Patients should be isolated so as not to spread the infection by airborne droplets.Providing these patients with protective face masks can reduce the risk of spreading the infection.
• Surveillance: identifying and tracing close contacts of people with pneumonic plague and providing chemoprophylaxis among them for 7 days.
• Obtain specimens that should be collected with care, following all preventive measures and infection control procedures, and then sent to laboratories for testing.
• Disinfection: It is recommended to regularly wash your hands with soap and water or use alcohol-based hand sanitizers.A 10% solution of household bleach can be used to disinfect large areas (the solution must be renewed daily).
• Observance of precautions for burial of the deceased: spraying antiseptics on the face / chest of corpses of patients presumably dead from pneumonic plague is impractical and not recommended. Cover the area with an antiseptic-soaked cloth or absorbent material.

Surveillance and control.

To carry out surveillance and control, it is necessary to conduct a survey of animals and fleas involved in the plague cycle in the region, as well as the development of environmental control programs aimed at studying the natural zoonotic nature of the infection cycle and limiting the spread of the disease.Active long-term surveillance of foci of animal habitation, accompanied by immediate response measures during outbreaks of disease in animals, can successfully reduce the number of outbreaks of plague in humans.

An informed and vigilant health workforce (and community) is essential for an effective and efficient response to outbreaks of plague to enable rapid diagnosis and appropriate care of those who are infected, identify risk factors, maintain continuous surveillance, and control vectors and vectors. owners, laboratory confirm diagnoses and communicate test results to competent authorities.

WHO response.

WHO’s goal is to prevent outbreaks of plague by conducting surveillance and helping high-risk countries develop preparedness plans. Because the reservoir of infection in animals varies from region to region, which influences the level of risk and conditions of transmission to humans, WHO has developed specific recommendations for the Indian subcontinent, South America and sub-Saharan Africa.

WHO is collaborating with ministries of health to support outbreak countries to respond to outbreaks on the ground.

(according to the official WHO website – http://www.who.int).

Mongolian Ministry of Health announced the death of a 15-year-old teenager from the plague :: Society :: RBK

Photo: Vladimir Prycek / CTK / Global Look Press

Fifteen-year-old teenager dies of bubonic plague in western Mongolia.This was confirmed by the results of laboratory tests, the Mongolian Ministry of Health reports on Facebook.

15 people who came into contact with the teenager were quarantined.

As the department specifies, a teenager in the aimag (province) Gov-Altai ate marmot meat. This animal is a frequent carrier of the bubonic plague.

Medvedev calls plague cases near Russian borders worrying

Earlier in the Khovd aimag, in the western part of Mongolia, two cases of bubonic plague were detected among humans.Also, the plague was found in one resident of the city of Bayan-Nur in northern China.

Plague: symptoms, forms, treatment

How can you get infected with plague

There are many opportunities to pick up the “plague microbe”. Contact with any carrier or vector is enough for a person. A wild animal, which, for example, was killed in a hunt, can be contagious. When cutting it, bacteria can get on the human skin. So, in 2014-2015 in Altai, two hunters became infected with the plague, butchering marmots.The infection entered the body through small lesions on the skin. Prior to that, since 1961 on the territory of the Russian Federation, plague in humans has not been registered even once. A similar case happened in 2013 with a 15-year-old teenager in Kyrgyzstan, who fried a marmot kebab after cutting it up7.

If you are traveling to an area recognized as a natural hotbed of plague, remember the following rules:

• Use insect repellants, especially fleas (sprays, ointments).
• Do not touch animals without being sure they are not infected.
• Do not touch the tissues of any dead animals, their secretions, body fluids (blood).
• Wash your hands regularly with soap and water or disinfect them with an alcohol-based solution.
• Heat vegetables and fruits with boiling water, do not use unboiled milk and water.

A dog can become infected with the plague (and bring it into the house) – through contact with infected wild individuals, soil, water.The infection can affect horses, sheep, and cows. Eating inadequately processed meat or milk from these animals may cause contamination. But mostly people get infected from rat fleas, which, when bitten, throw bacteria into the blood or onto the surface of the skin. In addition, even flea droppings that remain on the surface of the body are enough. However, it is not possible to get infected from any flea, but only from the one that previously parasitized on a rat infected with plague7.

Figure 1. Scheme of human infection through domestic animals.Image: CDC website

Another route of infection is airborne droplets. It is the most dangerous, since any infected person or animal easily and constantly releases the plague pathogen into the air. In this form of the disease – pneumonic plague – the infection spreads as quickly as possible.

Due to the extensive intoxication of the body resulting from the activity of bacteria, a person behaves inappropriately. In various studies, scientists note that the patient’s behavior can be mistaken for the behavior of a person under the influence of alcohol:

• excited state;
• anxiety;
• slurred speech;
• dull hearing;
• unsteady and unsteady gait;
• swollen, flushed face with absent expression;
• Lively, shiny, but motionless eyes.

Pay attention to the tongue – a chalk-like lime-white coating forms on it. The patient complains of a fever in the lower abdomen and constantly ask for a drink. However, drinking does not quench your thirst. Then chills and vomiting begin. Based on these signs, any doctor can diagnose severe intoxication. However, they still do not provide a basis for a confident diagnosis of plague.

What symptoms should cause alarm

The first signs may appear 1-7 days after the actual infection.This is exactly the incubation period for Yersinia pestis. The three most common forms of plague are bubonic, septic, and pneumonic. Now about 75% of all clinical cases are due to bubonic plague, about 17% – to septic and about 8% – to pneumonic7. They have their own distinctive features, which we will discuss below. However, as common symptoms for all forms, the World Health Organization identifies:

• sharp rise in temperature;
• chills;
• headache;
• body aches;
• weakness;
• nausea;
• vomiting.

Typical signs of plague, characteristic of almost any clinical case, are an abrupt onset and headache. The disease is always acute.

There is a known case in one of the southern republics of the USSR, when a patient with symptoms of severe intoxication was denied medical assistance under the pretext that he was intoxicated. Unfortunately, a few hours later the man was found in the courtyard of the polyclinic with no signs of life.He was posthumously diagnosed with plague7.

Plague Treatment

Any patient suspected of having this disease will be immediately hospitalized and isolated. Treatment activities begin without delay. Basically, this is antibacterial and detoxification therapy.

Plague is a very dangerous infection. The patient is isolated immediately after diagnosis. Protective suits should be worn by the treating physicians. Photo by Los Muertos Crew: Pexels

Antibiotics were created in the middle of the twentieth century that successfully fight the plague pathogen.These are aminoglycosides, tetracyclines, chloramphenicol. They are prescribed in a dose that corresponds to the form of the disease.

Streptomycin is considered one of the most effective antibiotics. It is administered intramuscularly 2 times a day for 10 days. A common treatment regimen with the use of gentamicin, doxycycline, chloramphenicol, chloramphenicol. In any case, standard antibiotic therapy lasts 10 days. Doxycycline has limitations for use in cases of infection of pregnant women.Chloramphenicol is not used in children.

However, antibiotic therapy alone is not enough, since a powerful process of intoxication is launched in the body.

• Saluretics are prescribed to restore the volume of urine excreted. These include drugs with active ingredients furosemide, ethacrynic acid.
• To normalize the work of the heart, drugs with the active substance reopolyglucin are used.
• To improve hemodynamics (blood movement), glucocorticosteroid drugs are used.

When carrying out detoxification therapy, it is important to remove toxins, correct hemostasis parameters, stabilize blood supply and functions of vital organs. For this, the patient is injected intravenously (through a dropper) with glucose-salt solutions and colloids: albumin, Ringer-Locke’s solution, polyglucin and others.

With the development of antibiotics, vaccines and antibacterial drugs, the treatment of plague is not a problem.However, it is imperative to seek prompt medical attention at the first symptoms. If therapy is started on time, there is no reason for worry – the prognosis is almost always favorable.

Plague Agent

The cause of the disease is the rod-shaped bacterium Yersinia pestis (plague bacillus), which, according to research data, has existed for more than 20 thousand years. It is popularly called the “plague microbe”. It multiplies rapidly in nutrient media and is transmitted in many ways.The most dangerous is airborne.

Facts about the “plague microbe”

• It tolerates freezing well, for example, at -22 ° C it can exist for up to 4 months. And at high temperatures it dies. At +50 … + 70 ° C – after 10 minutes, in boiling water – after 1 minute.
• Does not tolerate direct sunlight and dies in 2-3 hours.
• Contained in any secretions of an infected organism: saliva, sputum, etc.d.
• Can be stored in milk, water, soil, vegetables and fruits. In particular, on clothes – up to 6 months.

The plague bacterium is extremely aggressive towards the human body and, if untreated, is fatal. In addition to Yersinia pestis, there are 6 other types of bacteria that can cause this disease. The disease develops epidemic or pandemic, as a rule, with a high mortality rate7, therefore it is considered to be as dangerous as possible.

There are plague outbreaks every year in the Democratic Republic of the Congo, Madagascar and Peru. These are the most unfavorable countries in terms of the risk of infection. In the rest of the world, natural foci were recorded in Kazakhstan, Turkmenistan, Uzbekistan, Mongolia, China, India, Madagascar, Mozambique, Uganda, Tanzania, Brazil, Bolivia, Ecuador.

Russian tourists, businessmen, employees of companies who stay in these countries need to know exactly where the natural foci of the plague are located.And take steps to reduce the risk of infection7.

Who carries the infection

Carriers of infection are various rodents (rats, field mice, shrews, gerbils and voles) and some animals, mainly living in the steppe zone. These are hares, gophers, marmots, tarbagans, hedgehogs. They secrete the causative agent of the plague with droppings, bacteria are contained in dead animals – so they get into water, soil, from where they are spread further by other individuals.The carriers are most often fleas that parasitize on carriers, live in the soil³.

The yellow ground squirrel is a carrier of infection. Photo: Joint831 / Wikipedia (CC BY-SA 3.0)

Caution! Plague!

Scientists identify many natural foci of plague. These are the geographical locations where this infection circulates. Such places have been forming for millennia, and the main condition for the circulation of Yersinia pestis is the presence of a large number of carriers and vectors. Natural foci of the disease occupy about 7% of the land.An exclusively “imported” plague exists only in Australia and Antarctica. On the rest of the continents, there are areas where the risk of infection is highest.

Since natural foci are characterized by the presence of a large number of rodents (most often gophers), they are concentrated mainly in the steppe and forest-steppe zones9. In Russia it is:

• Ingushetia.
• Tyva (Ovyursky and Mongun-Taiginsky districts).
• Gorny Altai (Kosh-Agach District).
• Kabardino-Balkaria (Tyrnyauz, Baksan, Elbrus, Zolsky districts).
• Karachay-Cherkessia (Karachaevsky, Malokarachaevsky regions).
• Dagestan (Tarumovsky, Babayurtsky, Kizlyarsky, Kulinsky, Agulsky, Nogaysky, Buinaksky districts).
• Kalmykia (Chernozemelsky, Yashkulsky, Caspian, Iki-Burilsky regions).
• Chechen Republic.
• Stavropol Territory (Kursk District).
• Astrakhan region (Chernoyarsky, Narimanovsky, Limansky districts).

In the Russian Federation, the epidemic situation is called unstable, since there are natural foci of infection in the country, Russia borders on countries where plague outbreaks have been repeatedly recorded7.

Plague outbreak in the Himalayas. Photo: CDC Global / Flickr (CC BY 2.0)

Recent Major Outbreaks

The World Health Organization has estimated that 15,243 cases of plague infection occurred in 16 countries in Asia, Africa and America in 2003-2011. The lethal outcome was 5.9%. In general, almost 98% of all infections and more than 96% of deaths occur in Africa5.

• In 2004, several animals and humans fell ill with suspected bubonic plague in Turkmenistan and Uzbekistan.
• In 2005-2006, 1304 cases of pneumonic plague were recorded in the Democratic Republic of Congo. At the moment, this is the most dangerous place on Earth.
• In August 2009, Ziketan City in Qinghai Province was isolated due to an outbreak.
• In August 2010, 17 people fell ill with pneumonic and bubonic plague in Peru (Ascope province, La Libertad department).
• In 2010, more than 300 people became infected in Madagascar, in 2014 – more than 100.Madagascar is the second most dangerous place with regular outbreaks of the disease5.

Video 1. Outbreak of the bubonic plague in China. How the disease was defeated

What symptoms are noticeable at the first clinical examination

During the initial physical examination, the doctor in most cases records a sharp tachycardia. The patient’s heart beats so unevenly that it is sometimes difficult to calculate the pulse rate. It can become threadlike.On examination, signs of heart and kidney failure are also noticeable. The abdomen is swollen, and the urine takes on a pronounced dark shade. These and the above symptoms are characteristic during the initial period of plague development. Further, signs of local, general lesions appear, which indicate a certain form of the disease.

A lethal outcome is also possible in the initial period – if the disease develops with lightning speed. The body is going through a severe infectious-toxic shock and may not be able to cope with the infection.

Symptoms of bubonic plague

The name of this form of the disease comes from the Arabic and Greek words “juma” and “bubo”, meaning “bob” and “groin”. A characteristic feature is inflammation of the lymph nodes in the groin (more than 50% of cases). Inflamed lymph nodes outwardly resemble beans, beans. Buboes appear within a few hours after the true onset of the disease. They also develop in the armpits (about 20% of cases), under the jaw and on the neck. Small ones resemble a hazelnut in size, large ones – a chicken egg.Buboes are very painful, so the patient tries to take a position in which the inflamed lymph node is not affected.

• Most often, a person develops one bubo in the groin. The inflammation affects the neighboring tissues, the skin, therefore, after a day, the bubo resembles a dense tumor with clear boundaries, which is distinguished by acute pain.
• In the armpit, the tumor may have a jelly-like consistency. The danger is the spread of the infection to the lungs.
• Buboes on the neck are the most dangerous, accompanied by massive tissue edema up to the shoulder blades and lower chest.The patient’s condition deteriorates significantly as the edema spreads over the head. Development of meningitis is possible.

Buboes on the leg of a plague patient. Photo: PHIL CDC

How the Bubonic Plague Works

The peak of bubonic plague occurs on the 4th-6th day, when the intoxication of the body reaches its maximum. The patient constantly has a high temperature of about 40 ° C, he is in a fever. The face is flushed and swollen, and an expression of horror often appears on it. On physical examination, violations of the heart, enlargement of the liver are noticeable.Blood pressure decreases. Already at this stage, a lethal outcome is possible in a patient with low immunity.

If the patient is experiencing the peak of the disease, then on the 6-8th day the bubo turns red and swells noticeably, and after another 2 days it opens. From it, pus of a yellow-green color is released, in which traces of blood may be present. Pus has no obvious smell. During this period, the patient becomes much better. If the body has not been attacked by a secondary infection, the prognosis is favorable. The overgrowth of a purulent fistula occurs slowly – within 3-4 weeks.A deep scar forms in its place.

At any time of the disease, before the purulent breakthrough of bubo, the infection can spread to other lymph nodes and the formation of secondary buboes. This is one of the most common complications.

Temperature with bubonic plague

• In some cases, 1-2 days before the appearance of the bubo, the patient is worried about a fever with a high temperature. After the onset of inflammation, the temperature is consistently high – 39-40 ° C.
• If it began to gradually and steadily decline, this is a positive sign.
• If there was a sharp decline and a subsequent sharp increase, on the contrary, this indicates sepsis and a significant deterioration and poor prognosis.

Complications of bubonic plague

In the absence of timely treatment, the inflammatory process often spreads to other organs and tissues: lungs, brain, and other lymph nodes.Development of pneumonia, meningitis is possible. But the main complications that are diagnosed in most cases of untreated disease are infectious-toxic shock and disseminated intravascular coagulation syndrome (blood clotting disorder). They are expressed in the form of rapidly developing gangrene of the fingers and toes, feet, and individual areas of the skin.

Gangrene is one of the complications of the plague. Photo: PHIL CDC

Septic Plague Symptoms

This form is characterized by a rapid current – only 2-4 days. In some cases, the duration of the illness is only a few hours.Requires immediate treatment, since death is inevitable without medical care. The incubation period differs in the same speed – from the moment of infection to the first symptoms, it can take several hours or 1-2 days.

The onset of the disease is always sudden, violent and acute. The patient immediately develops symptoms of severe intoxication:

• acute headache;
• temperature 39-40 ° C;
• chills;
• pain in muscles, joints;
• nausea with vomiting.

How septic plague proceeds

2-4 hours after the onset of the disease, the patient’s psyche is disturbed – most often he is in an agitated state. The temperature is above 40 ° C, blood is noticeable in the vomit, a rash appears on the skin. The face takes on a suffering expression.

Examination by a doctor reveals heart dysfunction, an increase in heart rate up to 130 beats / min. In the next day, signs of tachycardia intensify, focal traces of internal hemorrhages appear on the body.In some patients, they merge into large spots – the so-called “death fields”. There are clear traces of blood in the urine. Patients are tormented by diarrhea, blood is noticeable in the discharge. The work of the kidneys is disrupted, the formation of urine stops. If medical assistance is not provided on the first day, usually by the end of the second, the disease ends in death.

Symptoms of pneumonic plague

The disease is quickly transmitted by airborne droplets, therefore it is the most dangerous from an epidemiological point of view.Patients fall ill suddenly. Literally an hour ago, a person who felt great begins to shake with chills. He develops all the main symptoms of the plague (headache, high fever, nausea, vomiting, aching muscles and joints), plus cutting pains in the chest that are characteristic of this form.

An important distinguishing feature is that shortness of breath develops in the first hours. Physical examination reveals tachycardia, arrhythmia. However, there are initially no pulmonary functional disorders.

How pneumonic plague develops

When coughing and breathing, the patient releases an infection into the air – this should be taken into account when observing safety measures. An important symptom is a wet cough with phlegm. It most often appears by the end of the first day of the disease (in some cases, from the very beginning). The sputum contains a huge amount of the “plague microbe”. The sputum has a liquid consistency (for example, with pneumonia, it is thicker). Its character changes as the disease progresses. At first it is transparent, then it stands out with foam, becomes glassy, ​​then traces of blood appear in it.Eventually the phlegm becomes constantly bloody.

On the 1st day, the condition quickly and significantly worsens. It is hard for the patient to breathe, he is acutely short of air, constantly agitated, trying to get up and approach the open window, door. The height of the disease lasts from several hours to 2 days. During this period, the body experiences a severe toxic damage.

On the 2nd day, excitement is replaced by lethargy due to general depression of the central nervous system.Patients are delirious, their speech becomes slurred, coordination is impaired, sensitivity to light increases. They still try to stay close to fresh air sources. Arrhythmia, acute renal failure increases, blood circulation is impaired. Chest pains become more severe and make it difficult to breathe.

On the 3rd day, pulmonary edema develops, bloody foamy sputum appears. The patient may fall into a coma, the pulse is barely palpable. Cyanotic spots of internal hemorrhages appear throughout the body and especially on the face.In such cases, death is inevitable.

Diagnostics

Successful treatment of plague depends on timely seeking medical attention. This should be done as quickly as possible – in the very first hours after the onset of symptoms. The pathogen can only be identified in laboratory conditions. Bacteria are found in blood smears by direct microscopy7. Therefore, with a sharp deterioration in health and suspicion of plague, you should immediately contact the clinic and insist on an emergency blood and urine test.The disease must be differentiated from other infectious diseases, in particular, acute purulent lymphadenitis, anthrax, glanders.

Microscopy of smears allows you to get a preliminary conclusion after 1-2 hours. Bacteriological inoculation gives reason to deliver the final analysis after 5-7 days. However, antibiotic therapy should be started immediately after pre-trial detention. A delay of 24 hours already threatens with serious complications.

Figure 2. Bubonic plague.Image: Artemida-psy / Depositphotos

Prevention of the spread of plague

People living in areas of natural foci of the disease are vaccinated. In these areas, rodents and fleas are regularly controlled by pest control. In private homes, you need to store food in places inaccessible to rodents, remove garbage and waste that attract them. When traveling in nature, insect repellents should be used. If there is a need to spend the night in the steppe, you need to carefully choose a place away from the holes of rodents, the site should be inspected for the presence / absence of droppings.

Conclusion

In the modern world, there are several natural foci of plague, where it is necessary to observe safety measures as much as possible. You need to be especially careful when traveling to the Democratic Republic of the Congo, Peru and Madagascar. However, it must be remembered that 11 natural foci are also located on the territory of the Russian Federation. If infection nevertheless occurs, you need to as soon as possible, in the very first hours, seek medical help and take a blood test. Timely started treatment (in the first 24 hours) is the key to a positive result.Plague in the modern world

Sources

1. Arutyunov Yu.I., Pichurina NL, Sudyina LV, Trukhachev AL. Plague in China: Epidemiological and Epizootic Aspects // Infectious Diseases: News, Opinions, Education. – 2019. – T. 8, No. 3. – P. 70–77.

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Rodents are the traditional carriers of the plague. This time, the source of infection was an infected squirrel.

In the United States, for the first time in 5 years, a case of human infection with septic plague, an infectious blood disease, has been identified.The patient has already recovered. The American edition of The Denver Post reports this, citing information from the Colorado Department of Health.

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A week earlier, proteins that carry bubonic plague were identified in the same state. At least fifteen dead animals were found in the vicinity by residents of the city of Morrison. In this regard, the state authorities warn about the need to observe precautions, not to let pets into the forest, and if you suspect a disease, consult a doctor.

Colorado has been trying to eradicate the plague since the 1940s. In total, 21 people were infected with the plague in this state from 2005 to 2015, the last 5 years “plague lull” lasted.

Important

Bubonic plague found in northern China

As a reminder, in the Inner Mongolia Autonomous Region (PRC) until the end of 2020, the third level of preventive measures has been announced in connection with the outbreak of bubonic plague.The disease was discovered in a cattle breeder from the Bayan-Nur district, a significant part of which is occupied by the Uradskaya steppe.

An outbreak of bubonic plague was also registered in Mongolia, one of the cases, a 15-year-old teenager, died. The cause of the disease was the eating of steppe marmots – rodents, which are traditional carriers of the plague.

Septic plague is one of the three main forms of plague (along with bubonic and pneumonic). The disease is caused by the plague bacillus, and the vectors are infected fleas and, accordingly, the rodents on which they live.It is also possible infection by airborne droplets from an already ill person.

Important

An adolescent infected with bubonic plague died in Mongolia

In the Middle Ages, infection with septic plague in 99% of cases was fatal. Today, timely started treatment can save the life of a person who contracted the disease.

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