How is brucellosis transmitted from animals to humans. What are the primary symptoms of brucellosis. Which occupations are at higher risk of contracting brucellosis. How can brucellosis be prevented and treated effectively. What are the potential complications of chronic brucellosis. Why is brucellosis more common in certain parts of the world. How does brucellosis affect various animals and marine mammals.

Understanding Brucellosis: A Zoonotic Bacterial Infection

Brucellosis is a bacterial infection that primarily spreads from animals to humans. This zoonotic disease affects hundreds of thousands of people and animals worldwide, posing significant health risks in various regions. The bacteria responsible for brucellosis can infect a wide range of animals, including domestic livestock and wildlife, making it a concern for both public health and animal husbandry.

What Causes Brucellosis?

Brucellosis is caused by bacteria belonging to the genus Brucella. These bacteria can infect various animal species, with different Brucella species preferentially affecting certain hosts. The most common species that cause human infections are:

• Brucella melitensis (primarily infects goats and sheep)
• Brucella abortus (mainly affects cattle)
• Brucella suis (infects pigs and wild hogs)
• Brucella canis (affects dogs)

These bacteria can survive in various environments and are highly infectious, requiring only a small number of organisms to cause disease in humans.

Transmission Routes: How Brucellosis Spreads to Humans

Understanding the transmission routes of brucellosis is crucial for preventing its spread. The bacteria can enter the human body through multiple pathways, often related to close contact with infected animals or consumption of contaminated animal products.

Consumption of Unpasteurized Dairy Products

The most common route of transmission is through the consumption of raw or unpasteurized dairy products from infected animals. This includes:

• Milk
• Cheese
• Ice cream
• Butter

Pasteurization effectively kills Brucella bacteria, making properly processed dairy products safe for consumption.

Inhalation of Contaminated Aerosols

Brucella bacteria can spread through the air, particularly in environments where infected animals are present or their tissues are being processed. This poses a risk to:

• Farmers
• Veterinarians
• Slaughterhouse workers
• Laboratory personnel working with Brucella cultures

Direct Contact with Infected Animals

The bacteria can enter the human body through cuts, abrasions, or mucous membranes when in contact with infected animal tissues, blood, urine, vaginal discharges, or aborted fetuses. This is a particular concern for:

• Livestock handlers
• Veterinarians
• Hunters

Rare Transmission Routes

While uncommon, brucellosis can occasionally spread through other means:

• Person-to-person transmission (extremely rare)
• Mother-to-child transmission during pregnancy or breastfeeding
• Sexual transmission
• Contaminated blood transfusions or organ transplants

Recognizing Brucellosis: Symptoms and Clinical Presentation

Brucellosis can be challenging to diagnose due to its varied and often non-specific symptoms. The incubation period can range from a few days to several months, adding to the difficulty of identifying the infection source.

Acute Brucellosis Symptoms

Initial symptoms of brucellosis often resemble those of influenza and may include:

• Fever (often undulant or intermittent)
• Chills and sweats
• Fatigue and weakness
• Headache
• Muscle and joint pain
• Loss of appetite
• Weight loss

Chronic Brucellosis Manifestations

If left untreated, brucellosis can become chronic, leading to long-term health issues:

• Recurrent fevers
• Chronic fatigue
• Depression
• Arthritis
• Neurological symptoms

Is chronic brucellosis always a result of untreated acute infection? While untreated acute brucellosis often leads to chronic infection, some individuals may develop chronic symptoms even after receiving treatment, emphasizing the importance of early diagnosis and appropriate medical care.

High-Risk Occupations and Populations for Brucellosis

Certain professions and populations are at a higher risk of contracting brucellosis due to their increased exposure to infected animals or animal products.

Occupational Risks

• Veterinarians and animal health workers
• Farmers and ranchers
• Slaughterhouse employees
• Dairy industry workers
• Laboratory personnel handling Brucella cultures
• Hunters and wildlife management professionals

Geographical High-Risk Areas

While brucellosis is relatively rare in many developed countries due to effective animal vaccination programs and food safety measures, it remains endemic in various parts of the world:

• Mediterranean region
• Middle East
• Central and South America
• Eastern Europe
• Asia
• Africa

Travelers to these regions, particularly those consuming local dairy products or engaging in activities involving animal contact, may be at increased risk.

Diagnosis and Treatment of Brucellosis

Accurate diagnosis and prompt treatment are crucial for managing brucellosis effectively and preventing complications.

Diagnostic Methods

Diagnosing brucellosis typically involves a combination of clinical assessment, patient history, and laboratory tests:

• Blood cultures to isolate the bacteria
• Serological tests to detect antibodies against Brucella
• Polymerase chain reaction (PCR) for rapid detection of Brucella DNA
• Imaging studies to assess organ involvement in complicated cases

Treatment Approach

Brucellosis treatment usually involves a combination of antibiotics taken for several weeks to months. The standard regimen includes:

• Doxycycline combined with rifampin or streptomycin
• Alternative combinations for special populations (e.g., pregnant women, children)

Can brucellosis be cured completely? With appropriate antibiotic treatment, most cases of brucellosis can be cured. However, the infection may recur in some cases, necessitating repeated or prolonged treatment courses. Close medical follow-up is essential to ensure complete eradication of the bacteria.

Complications and Long-Term Effects of Brucellosis

While many individuals recover fully from brucellosis with proper treatment, the infection can lead to serious complications, especially if left untreated or in cases of chronic infection.

Organ-Specific Complications

• Endocarditis (inflammation of the heart’s inner lining)
• Neurobrucellosis (central nervous system involvement)
• Hepatitis and liver abscesses
• Respiratory complications (e.g., pneumonia, pleural effusions)
• Genitourinary issues (e.g., orchitis, epididymitis)

Musculoskeletal Involvement

Brucellosis can significantly impact the musculoskeletal system, leading to:

• Arthritis (particularly affecting large joints)
• Spondylitis (inflammation of the spine)
• Osteomyelitis (bone infection)
• Bursitis and tendinitis

Psychological and Cognitive Effects

Chronic brucellosis may also result in:

• Depression and anxiety
• Cognitive impairment
• Chronic fatigue syndrome

How long can the effects of chronic brucellosis persist? The duration of chronic brucellosis symptoms can vary greatly among individuals. Some may experience lingering effects for months or even years after the initial infection, highlighting the importance of early diagnosis and comprehensive treatment.

Prevention Strategies: Protecting Humans and Animals from Brucellosis

Preventing brucellosis involves a multi-faceted approach targeting both animal and human populations. Effective prevention strategies can significantly reduce the incidence of this zoonotic disease.

Animal Health Measures

• Vaccination of livestock (particularly cattle, sheep, and goats)
• Regular testing and culling of infected animals
• Proper disposal of infected animal tissues and products
• Quarantine measures for newly introduced animals

Food Safety Practices

• Pasteurization of milk and dairy products
• Proper cooking of meat from potentially infected animals
• Avoiding consumption of raw or unpasteurized dairy products, especially in endemic areas

Occupational Safety

• Use of personal protective equipment (PPE) when handling potentially infected animals or their products
• Implementation of biosafety measures in laboratories working with Brucella
• Education and training for high-risk occupational groups

Public Health Initiatives

• Surveillance and reporting systems for human and animal brucellosis cases
• Public awareness campaigns about the risks and prevention of brucellosis
• Travel advisories for individuals visiting endemic regions

What role does international cooperation play in brucellosis prevention? International collaboration is crucial in controlling brucellosis, especially in regions where the disease is endemic. Sharing of data, research findings, and best practices among countries can lead to more effective global prevention strategies and reduce the overall burden of the disease.

Brucellosis in Wildlife and Marine Mammals: Ecological Considerations

While brucellosis is often associated with domestic livestock, its presence in wildlife and marine mammals poses unique challenges for disease control and conservation efforts.

Terrestrial Wildlife Reservoirs

Various wild animal species can serve as reservoirs for Brucella bacteria, including:

• Bison and elk in North America
• Wild boars in Europe and Asia
• African buffalo in parts of Africa

These wildlife reservoirs can complicate eradication efforts and pose a risk of transmission to domestic animals and humans.

Marine Mammal Brucellosis

Brucella infections have been documented in several marine mammal species, including:

• Seals
• Sea lions
• Dolphins
• Porpoises
• Whales

The Brucella species affecting marine mammals (B. ceti and B. pinnipedialis) are distinct from those typically infecting terrestrial animals but can potentially cause zoonotic infections in humans who handle infected marine mammals or their tissues.

Ecological Impact and Conservation Concerns

Brucellosis in wildlife and marine mammals can have significant ecological impacts:

• Reduced reproductive success in infected populations
• Increased mortality rates, particularly in young animals
• Altered migration patterns or social behaviors
• Potential long-term effects on population dynamics and ecosystem balance

How does wildlife brucellosis affect conservation efforts? The presence of brucellosis in wildlife populations complicates conservation strategies, particularly in protected areas or for endangered species. Management approaches must balance disease control with conservation goals, often requiring innovative and collaborative solutions between wildlife biologists, veterinarians, and public health officials.

Understanding the complex interplay between brucellosis in domestic animals, wildlife, and human populations is essential for developing comprehensive control strategies. This One Health approach, which recognizes the interconnectedness of human, animal, and environmental health, is crucial for effectively managing brucellosis and other zoonotic diseases on a global scale.

Brucellosis – Symptoms & causes

Overview

Brucellosis is a bacterial infection that spreads from animals to people. Most commonly, people are infected by eating raw or unpasteurized dairy products. Sometimes, the bacteria that cause brucellosis can spread through the air or through direct contact with infected animals.

Signs and symptoms of brucellosis may include fever, joint pain and fatigue. The infection can usually be treated with antibiotics. However, treatment takes several weeks to months, and the infection can recur.

Brucellosis affects hundreds of thousands of people and animals worldwide. Avoiding raw dairy products and taking precautions when working with animals or in a laboratory can help prevent brucellosis.

Products & Services

Symptoms

Symptoms of brucellosis may show up anytime from a few days to a few months after you’ve been infected. Signs and symptoms are similar to those of the flu and include:

• Fever
• Chills
• Loss of appetite
• Sweats
• Weakness
• Fatigue
• Joint, muscle and back pain
• Headache

Brucellosis symptoms may disappear for weeks or months and then return. Some people have chronic brucellosis and experience symptoms for years, even after treatment. Long-term signs and symptoms may include:

• Fatigue
• Recurrent fevers
• Inflammation of the inner lining of the heart chambers (endocarditis)
• Joint inflammation (arthritis)
• Arthritis of the spinal bones (spondylitis)
• Arthritis of joints where the spine and pelvis connect (sacroiliitis)

When to see a doctor

Brucellosis can be hard to identify, especially in the early stages, when it often resembles other conditions, such as the flu. See your doctor if you develop a rapidly rising fever, muscle aches or unusual weakness and have any risk factors for the disease, or if you have a persistent fever.

Causes

Brucellosis affects many wild and domestic animals, including:

• Cattle
• Goats
• Sheep
• Pigs and wild hogs
• Dogs, especially those used in hunting
• Deer
• Elk
• Bison
• Caribou
• Moose
• Camels

A form of brucellosis also affects harbor seals, porpoises and certain whales.

The most common ways that bacteria spread from animals to people are by:

• Eating raw dairy products. Brucella bacteria in the milk of infected animals can spread to humans in unpasteurized milk, ice cream, butter and cheeses. The bacteria can also be transmitted in raw or undercooked meat of infected animals.
• Inhaling contaminated air. Brucella bacteria spread easily in the air. Farmers, hunters, laboratory technicians and slaughterhouse workers can inhale the bacteria.
• Touching blood and body fluids of infected animals. Bacteria in the blood, semen or placenta of an infected animal can enter your bloodstream through a cut or other wound. Because normal contact with animals — touching, brushing or playing — doesn’t cause infection, people rarely get brucellosis from their pets. Even so, people who have weakened immune systems should avoid handling dogs that are known to have the disease.

Brucellosis normally doesn’t spread from person to person, but in a few cases, women have passed the disease to their children during birth or through their breast milk. Rarely, brucellosis may spread through sexual activity or through contaminated blood or bone marrow transfusions.

Risk factors

While brucellosis is rare in the United States, it is more common in other parts of the world, especially:

• Southern Europe, including Portugal, Spain, Turkey, Italy, Greece, Southern France
• Eastern Europe
• Mexico, South and Central America
• Asia
• Africa
• The Caribbean
• The Middle East

Occupations at higher risk

People who work with animals or who come into contact with infected blood are at higher risk of brucellosis. Examples include:

• Veterinarians
• Dairy farmers
• Ranchers
• Slaughterhouse workers
• Hunters
• Microbiologists

Complications

Brucellosis can affect almost any part of your body, including your reproductive system, liver, heart and central nervous system. Chronic brucellosis may cause complications in just one organ or throughout your body. Possible complications include:

• Inflammation of the inner lining of the heart chambers (endocarditis). This is one of the most serious complications of brucellosis. Untreated endocarditis can damage or destroy the heart valves and is the leading cause of brucellosis-related deaths.
• Arthritis. Joint inflammation is marked by pain, stiffness and swelling in the joints, especially the knees, hips, ankles, wrists and spine. Inflammation of the joints in your spine (spondylitis) or the joints linking the lower spine and pelvis (sacroiliitis) can be particularly hard to treat and may cause lasting damage.
• Inflammation and infection of the testicles (epididymo-orchitis). The bacteria that cause brucellosis can infect the epididymis, the coiled tube that connects the vas deferens and the testicle. From there, the infection may spread to the testicle itself, causing swelling and pain, which may be severe.
• Inflammation and infection of the spleen and liver. Brucellosis can also affect the spleen and liver, causing them to enlarge beyond their usual size.
• Central nervous system infections. These include potentially life-threatening illnesses such as inflammation of the membranes surrounding the brain and spinal cord (meningitis) or inflammation of the brain itself (encephalitis).

Prevention

To reduce the risk of getting brucellosis, take these precautions:

• Avoid unpasteurized dairy foods. In recent years in the United States, few cases of brucellosis have been linked to raw dairy products from domestic herds. Still, it’s best to avoid unpasteurized milk, cheese and ice cream, no matter what their origin. If you’re traveling to other countries, avoid all raw dairy foods.
• Cook meat thoroughly. Cook a whole cut of meat until it reaches an internal temperature of 145 F (63 C) and let it rest for at least three minutes — a medium doneness. Cook ground meat to 160 F (71 C) — well done. Cook all poultry, including ground poultry, to 165 F (74 C). When traveling outside of the United States, avoid undercooked meats.
• Wear gloves. If you’re a veterinarian, farmer, hunter or slaughterhouse worker, wear rubber gloves when handling sick or dead animals or animal tissue or when assisting an animal giving birth.
• Take safety precautions in high-risk workplaces. If you work in a laboratory, handle all specimens under appropriate biosafety conditions. Slaughterhouses should also follow protective measures, such as separating the killing floor from other processing areas and use of protective clothing.
• Vaccinate domestic animals. In the United States, an aggressive vaccination program has nearly eliminated brucellosis in livestock herds. Because the brucellosis vaccine is live, it can cause disease in people. Anyone who has an accidental needle stick while vaccinating an animal should be treated.

Surveillance | Brucellosis | CDC

• Case Definition
• Historic CDC Surveillance Data
• Case Reporting
• Case Notification
• Data Submission

Disease surveillance is a cornerstone of public health practice, enabling early detection, rapid characterization, and efficient response to public health threats like brucellosis. Healthcare providers and public health practitioners are key partners in effective brucellosis surveillance.

Brucellosis Case Definition

The brucellosis surveillance case definition, available at the National Notifiable Diseases Surveillance System (NNDSS) site, provides a set of uniform criteria used to define the disease for public health surveillance. This definition enables public health officials to classify and count cases consistently across jurisdictions.

Historic CDC Surveillance Data

CDC maintains brucellosis surveillance data that are published weekly and annually. These data are available in the NNDSS notifiable infectious disease data tables data tables.

Case Reporting

Brucellosis is a reportable condition in all states and territories. Brucellosis cases must be reported to jurisdictions when identified by a healthcare provider, hospital, or laboratory. Specific reporting requirements – including who must report, how to report, and timing of report – may vary by jurisdiction.

Case Notification

Brucellosis is a nationally notifiable condition (NNC). In 2009, the Council of State and Territorial Epidemiologists (CSTE)external icon developed criteria pdf icon[PDF – 44 KB] for timeliness of NNC case notifications. CSTE requests the following notifications pdf icon[PDF – 13 KB]external icon for confirmed or probable brucellosis cases, dependent on the situation:

Immediate, Urgent: Notification within 24 hours

• Notification criteria: In the event of multiple brucellosis cases, temporally or spatially clustered.
• What to do: The state/territorial epidemiologist (or delegate) should call the CDC Emergency Operations Center (EOC) within 24 hours of knowing the notification criteria are met.
• A CDC subject matter expert (SME) will call back within 4 hours and send written or email confirmation that the case notification was received by CDC.
• Electronic transmission to NNDSS should be completed by the next regularly scheduled transmission cycle (see Data Submission below).
  • Changes in case classification should also be submitted by the next regularly scheduled transmission cycle.

Following immediate, urgent notification:

• For subsequent epidemiologically linked cases: The state/territorial epidemiologist (or delegate) should directly notify the CDC staff who responded to the initial notification, rather than contacting the CDC EOC.
• If a patient is determined to meet case classification criteria during a discussion with CDC, additional notification to the CDC EOC is not needed.

Standard: Notification by electronic transmission

• Notification criteria: In the event of brucellosis cases that are NOT temporally or spatially clustered.
• Electronic transmission to NNDSS should be completed by the next regularly scheduled transmission cycle (see Data Submission).
  • Changes in case classification should also be submitted by the next regularly scheduled transmission cycle.

Data Submission

National-level monitoring of notifiable conditions helps protect the health of the nation. Information from surveillance notifications shared by health departments can be used to better understand disease occurrence, impacted populations, and appropriate prevention and response strategies.

If a patient meets probable or confirmed case criteria, CSTE requests that general information about the patient and disease be submitted to NNDSS using NETSS messages or the generic message mapping guide. For timeliness of electronic reporting, see Case Notification, above.

At this time, additional disease-specific (extended) data for brucellosis cases can be shared separately through the following channels:

• Brucellosis case report form (CRF)

The case report form is available in English as a fillable PDF form that can be completed electronically or can be printed and completed by hand. Completed forms can be emailed, faxed, or mailed to CDC.

Brucellosis Case Report Form pdf icon[PDF – 1086 KB, Print and Fillable PDF]

• Bacterial Special Pathogens Branch (BSPB) DCIPHER Portal

DCIPHER is a web-based data integration platform that is used by several CDC programs. CDC is now also using this platform for brucellosis surveillance, linking case data to CDC laboratory and NNDSS data.

DCIPHER features fillable forms, and point-and-click visualization and tabulation tools. These tools can be used by CDC and jurisdictions to rapidly aggregate and visualize case data, share visualizations and simple analyses, and link case data with other data sources to gain regional or national perspectives on outbreaks, other public health events, and surveillance.

Access to the BSPB DCIPHER portal is granted via SAMS credentialing. Options for data submission using DCIPHER include:

1. Direct entry into a web-based form, similar to the existing CRFs
2. Submission of a data extract from a jurisdictional surveillance system as a CSV file. Submitters can upload the CSV file directly into DCIPHER, via a SAMS folder, or send using another secure method

Jurisdictions may benefit from using the visualization and tabulation tools within DCIPHER, and can access the BSPB DCIPHER portal regardless of which method they choose to share disease-specific surveillance data.

To request DCIPHER access, for more information about the system, or if there are other surveillance-related questions, contact BSPB at [email protected].

Brucellosis: symptoms, diagnosis, treatment

In contact with animals or with thermally unprocessed products of animal origin, there is a risk of infection with brucellosis. This infectious disease affects many human organs and systems and easily becomes chronic with frequent relapses.

General information about infection

The causative agent of brucellosis is the bacterium Brucella, the main reservoir for which are domestic and wild animals and birds. Human infection occurs through contact with an infected animal. Ways of transmission of brucellosis – small wounds on the skin or mucous membranes, the digestive tract when eating animal products, the respiratory tract when inhaling air with infected dust.

Human infection is possible only from an animal. The existence of tick-borne brucellosis has not been proven – so far not a single case of transmission of this infection through tick bites has been recorded.

Brucella can be found not only in the body of animals, but also on their fur, in milk and even in frozen meat, as well as in the soil, where they enter with the feces of animals. The bacterium is excellently adapted to adverse conditions, remaining viable at low temperatures and in the absence of moisture from one and a half months to six months. However, it dies within half an hour when heated to 60 ° C, and when boiled, it is destroyed instantly. Therefore, eating animal products after heat treatment is completely safe.

Symptoms of disease

Between the penetration of bacteria into the body and the appearance of the first signs of brucellosis, at least a week passes, sometimes the incubation period lasts up to two months, but its most frequent duration is two weeks. Symptoms develop gradually and include:

• severe increase in body temperature up to 38-39°C, accompanied by chills and fever;
• increased sweating, especially during nocturnal sleep;
• a sharp decline in strength, a feeling of weakness;
• the appearance of pain in the joints of the limbs, tingling in different parts of the body.

The listed symptoms of brucellosis can be undulating in nature: gradually increase and intensify, then decrease and disappear for a while. The disease is systemic in nature and affects the human musculoskeletal system, nervous system and reproductive organs, provoking the development of concomitant ailments.

Pathogenesis

The development of brucellosis in humans goes through several stages.

1. Lymphogenic – bacteria penetrate the lymphatic system and occupy the lymph nodes with the lymph flow, without leading to their enlargement.
2. Hematogenous drift – having penetrated into the circulatory system, bacteria release toxins that act on nerve fibers through the blood.
3. Acute brucellosis – with the bloodstream, bacteria penetrate into the tissues of various organs, forming secondary foci of infection in the form of granulomas, and sometimes inflammatory abscesses.
4. Exofocal contamination – new foci of infection appear, an allergic reaction to unfavorable factors develops in the body, chronic brucellosis is formed, which lasts for several years with numerous relapses;
5. Residual effects – the final stage of the disease, which is characterized by deformation of bone tissue and joints, allergic manifestations and disorders of the nervous system, which are usually irreversible.

After the end of the disease, the patient develops temporary immunity, the duration of which is from six months to five years, after which the person can again become infected.

Infection detection

The technique for diagnosing brucellosis is well developed and is based on laboratory tests aimed at identifying the pathogen, which include:

• general blood test;
• biochemical blood test;
• bakposev biomaterials;
• serological examination;
• blood test for detection of antigens;
• PCR test for Brucella DNA;
• Brucella antibody testing.

In addition, to detect pathological changes in the patient’s body, ultrasound and x-ray studies of damaged organs may be needed.

How to treat brucellosis

Antibiotics are prescribed for the treatment of acute brucellosis. When the disease becomes chronic, these drugs cease to be effective, immunoglobulins with anti-brucellosis antibodies and vaccines with killed bacteria have a much more pronounced effect. Supportive and strengthening therapy is important – ultraviolet irradiation sessions, taking vitamin complexes, etc. When an allergic reaction occurs, antiallergic drugs are prescribed. During the recovery period, a visit to balneological resorts with radon and sulfur-radon waters is shown.

How to prevent illness

Unfortunately, the development of an effective long-acting vaccine that prevents the development of infection in humans has proved impossible. However, subject to simple measures to prevent brucellosis, it is quite possible to avoid the disease. For this you need:

• boil or pasteurize milk before eating;
• avoid dry-cured meat products;
• observe hygiene rules, wash hands after contact with animals, agricultural workers wear protective gloves;
• to vaccinate livestock, since the brucellosis vaccine for animals has long been developed, and in countries that practice blanket vaccination of livestock, this disease has practically disappeared.

In case of contact with an infected animal, it is necessary to monitor the state of health for at least six months, periodically taking tests for the presence of bacteria in biomaterials.

Frequently Asked Questions

Is brucellosis transmitted from person to person?

Medicine excludes the possibility of transferring brucellosis from person to person, since the bacterium cannot enter the body by airborne droplets or by contact. There are some data on the ways of brucellosis infection of infants through mother’s milk and fetus from a pregnant mother.

Why is brucellosis dangerous for humans?

Brucellosis is a severe infection, the main danger of which is the negative impact of the toxin released by bacteria on human organs and systems. The most common complications are endocarditis, the main cause of death from this infection, arthritis leading to deformity of the joints and bones, inflammation of the reproductive organs, liver and spleen, and infections of the nervous system.

Is there a cure for brucellosis today?

Modern medicine has the ability to completely cure patients with brucellosis, but only if the patient consults a doctor. Timely detection of the disease allows you to provide all the necessary assistance at an early stage and prevent the development of serious complications.

Brucellosis: symptoms, diagnosis, treatment

Bang and Traum’s disease, Bruce’s septicemia, Mediterranean, goat, Crimean fever – all these intricate terms hide one socially significant infectious and allergic disease – brucellosis. How can you get infected, what are the symptoms of this infection, how to treat it? The answers to these and other questions about brucellosis are in our article.

A bit of history

The first information about brucellosis appeared in the middle of the 19th century thanks to the English military surgeon J. Marston. He studied sick soldiers on the island of Malta and drew attention to the fact that they all ate goat’s milk. A little later, in 1887, British Army physician David Bruce isolated the brucellosis pathogen from the spleen of five English soldiers who died of a fever. Initially, it was named the Maltese micrococcus, and later renamed in honor of the discoverer scientist in brucella.

The connection of the disease with animals was finally established in the course of research by D. Bruce and other scientists already at the beginning of the 20th century. By this time, three types of Brucella had been isolated. Currently, six types of the causative agent of brucellosis are known, four of which are extremely dangerous for humans.

Features of the causative agent of brucellosis

Microorganisms of the genus Brucella are gram-negative bacteria that are resistant to low temperatures, but do not “like” high temperatures at all: when boiled, brucella dies instantly, and when heated to 60 degrees Celsius – within half an hour. Serious enemies of bacteria are direct sunlight and disinfectants.

Despite their apparent vulnerability, bacteria have qualities that allow them to parasitize the body for a long time, depleting it. One of these qualities is the ability to transform into specific L- and S-forms under the influence of antibiotics and immune cells. This feature leads to a chronic process with the subsequent development of complications.

Brucella secrete substances that inhibit the activity of macrophages (cells-“defenders” that are involved in the capture and destruction of pathogenic microorganisms). This creates conditions for parasitizing Brucella inside the cells of the immune system. Endotoxin, released during the death and destruction of these bacteria, causes severe intoxication of the body and leads to metabolic disorders in it.

How do you get brucellosis?

The main distributors of brucellosis are goats, sheep, pigs, cows, although all types of domestic animals and birds are susceptible to the disease. Usually, infection occurs when eating dairy products and meat that have not undergone sufficient heat treatment.

The contact route of penetration of the pathogen into the human body through damaged skin or mucous membranes is not excluded – when interacting with the hair, bedding, food and water of an infected animal. This explains the high incidence of brucellosis among livestock workers (milkmaids, shepherds, veterinarians, livestock specialists) and people involved in the processing of livestock products.

Brucellosis can also be contracted by aerogenic means, if you comb out the hair from a sick animal or cut it.

A sick person does not pose a danger to others. The exception is infection of the fetus from an infected mother.

After pathogens enter the body, they are captured by macrophages, multiply in them and penetrate into the lymph nodes. From there, the bacteria spread throughout the body through the blood and lymph.

Symptoms of brucellosis

It is possible to assume the presence of the disease by a set of complaints such as excruciating pain in the joints (mainly in the legs) against the background of increased sweating, severe weakness, as well as wave-like fever (with a sharp rise and fall in body temperature).

The spread of the causative agent of brucellosis throughout the body causes systemic damage to almost all organs. Patients have pathologies of the musculoskeletal system in the form of monoarthritis, polyarthritis, osteomyelitis, myalgia. There are inflammatory processes in the heart, lungs, genitourinary system. The defeat of the central nervous system in brucellosis is expressed in the form of meningitis, encephalitis, abscesses in the brain, atrophy of the optic nerve.

Brucellosis is also characterized by lymphadenitis (inflammation of the lymph nodes) and splenomegaly (enlarged spleen).

Diagnosis of brucellosis

Collection of complaints and anamnesis, examination is the first stage in the diagnosis of the infectious process. It is important to obtain information about whether the patient belongs to a risk group.

Isolation of bacteria is required to confirm the diagnosis. This is possible when a person has a blood test for brucellosis. The reaction of Coombs, Wright, RSK (complement fixation reaction), PCR diagnostics – these research methods make it possible to identify all forms of bacteria.

One of the easiest ways to diagnose an infection is the Berne skin test.

How and where is brucellosis treated?

The treatment of brucellosis consists of the following basic principles:

• measures aimed at combating the pathogen;
• elimination of pain syndrome;
• combating complications;
• rehabilitation.

Self-treatment for brucellosis is unacceptable. In the acute phase of the infectious process and with the development of complications, inpatient treatment is necessary. The selection of antibacterial and antiallergic drugs, physiotherapeutic procedures is carried out by the attending physician, depending on the phase and severity of the process, as well as the existing complications.

How to prevent infection with brucellosis?

To prevent infection, doctors recommend following a few simple principles:

• follow the rules of personal hygiene, especially when it comes to contact with domestic and farm animals;
• thoroughly wash and cook animal products;
• do not ignore the symptoms that appear and seek medical attention immediately.