What is the causative organism of bird flu. How does avian influenza spread among birds and humans. What are the symptoms of bird flu in humans. How does PAHO respond to the threat of avian influenza.

The Nature of Avian Influenza Virus

Avian influenza, commonly known as ‘bird flu’, is a disease that primarily affects birds. The causative organism belongs to the Orthomyxoviridae family of viruses. These viruses can be classified into two categories based on their pathogenicity:

• Low Pathogenic Avian Influenza Virus (LPAIV)
• Highly Pathogenic Avian Influenza Virus (HPAIV)

LPAIVs typically cause mild illness in birds, often going unnoticed or presenting without symptoms. On the other hand, HPAIVs, particularly those of subtypes H5 and H7 of type A, can cause severe illness in birds. These highly pathogenic strains can spread rapidly among different bird species, resulting in high mortality rates.

Zoonotic Potential of Avian Influenza

While most avian influenza viruses circulating in birds are not zoonotic, certain HPAI strains have demonstrated the ability to infect humans. This zoonotic potential poses a significant threat to public health. The main risk factor for human infection is direct or indirect exposure to infected animals or environments contaminated by their feces.

How does avian influenza spread to humans?

The transmission of avian influenza to humans primarily occurs through close contact with infected birds or contaminated environments. Activities that increase the risk of transmission include:

• Plucking infected poultry
• Handling infected poultry carcasses
• Preparing infected poultry for consumption, especially in domestic settings

Symptoms and Health Implications in Humans

When avian influenza infects humans, the symptoms can vary widely in severity. The range of symptoms includes:

1. Mild upper respiratory tract infections (fever and cough)
2. Severe pneumonia
3. Acute respiratory distress syndrome (difficulty breathing)
4. Shock
5. Death in extreme cases

What are the most common symptoms of avian influenza in humans?

The most common symptoms of avian influenza in humans are fever and cough, indicative of an upper respiratory tract infection. However, it’s crucial to note that symptoms can progress to more severe conditions, potentially leading to life-threatening complications.

Global Impact of Zoonotic Diseases

The emergence of pathogenic infectious diseases in the past two decades, including recent outbreaks of zoonotic diseases like avian influenza, has brought increased attention to the interconnectedness of animal and human health. Some key facts about zoonotic diseases include:

• 61% of known human pathogens are zoonotic
• Livestock disease outbreaks since the mid-1990s have cost an estimated $80 billion globally
• Closer contact between humans, domesticated animals, and wildlife due to habitat encroachment is a major factor in the emergence of new zoonoses

What factors contribute to the emergence of new zoonotic diseases?

Several factors contribute to the emergence of new zoonotic diseases:

1. Environmental changes
2. Globalization of food production and trade
3. Microbiological adaptation
4. Human behavioral factors
5. Rapid global travel and trade, facilitating disease spread

PAHO’s Strategic Response to Avian Influenza

The Pan American Health Organization (PAHO) has developed a comprehensive approach to support Member States in responding to the threat of pandemic influenza, including avian influenza. This approach includes:

• A strategic and operational plan based on WHO’s preparedness guidelines
• Collaboration with agricultural organizations like IICA
• Joint activities with veterinary services in countries for zoonosis control and food safety
• Organization of the Ministerial Level Inter-American Meeting on Health and Agriculture (RIMSA)

How does PAHO’s strategic plan address the various phases of a potential pandemic?

PAHO’s strategic and operational plan for responding to pandemic influenza includes guidelines for each phase of a potential pandemic. In the pre-pandemic phase, the plan emphasizes the importance of assessing countries’ capacities to respond to the threat. This assessment involves multiple sectors, including:

• Human and animal surveillance
• Health services
• Zoonosis control
• Agriculture
• Disaster response
• Civil defense
• Communication

Recent Developments in Avian Influenza Surveillance

PAHO has been actively working to strengthen regional avian influenza surveillance and response. Recent developments include:

• On March 16, 2023, PAHO announced efforts to enhance regional avian influenza surveillance and response capabilities
• On January 17, 2023, PAHO issued an alert regarding outbreaks of avian influenza in birds across ten countries in the Americas

Why is strengthening regional surveillance crucial in combating avian influenza?

Strengthening regional surveillance is critical in the fight against avian influenza for several reasons:

1. Early detection of outbreaks
2. Rapid response to contain the spread
3. Improved understanding of virus evolution and transmission patterns
4. Enhanced preparedness for potential human infections
5. Better coordination of resources and expertise across countries

The Role of Migratory Birds in Avian Influenza Transmission

Migratory wild birds play a significant role in the spread of avian influenza across different territories. Understanding their migration patterns and the potential for virus transmission is crucial for effective disease control strategies.

How do migratory birds contribute to the spread of avian influenza?

Migratory birds contribute to the spread of avian influenza in several ways:

• They can carry the virus over long distances during their seasonal migrations
• They may introduce the virus to new geographic areas
• They can potentially infect local bird populations at stopover sites
• Their interactions with domestic poultry can lead to virus transmission

Monitoring migratory bird patterns and conducting surveillance at key migration sites can help in early detection and prevention of avian influenza outbreaks.

Prevention and Control Measures for Avian Influenza

Preventing and controlling avian influenza requires a multi-faceted approach involving various stakeholders, including public health officials, veterinarians, and the poultry industry.

What are the key strategies for preventing avian influenza outbreaks?

Key strategies for preventing avian influenza outbreaks include:

1. Biosecurity measures in poultry farms
2. Regular surveillance and monitoring of bird populations
3. Rapid reporting and response to suspected cases
4. Vaccination programs for poultry in high-risk areas
5. Public education on safe handling of poultry and personal hygiene

Implementing these strategies can significantly reduce the risk of avian influenza transmission between birds and from birds to humans.

Economic Impact of Avian Influenza Outbreaks

Avian influenza outbreaks can have severe economic consequences, affecting the poultry industry, trade, and public health sectors. Understanding these impacts is crucial for developing comprehensive response strategies.

How do avian influenza outbreaks affect the global economy?

Avian influenza outbreaks impact the global economy in various ways:

• Direct losses to the poultry industry due to culling of infected flocks
• Trade restrictions on poultry products from affected regions
• Increased costs for disease control and prevention measures
• Potential loss of consumer confidence in poultry products
• Indirect costs related to public health responses and potential human infections

Mitigating these economic impacts requires coordinated efforts between public health authorities, the agriculture sector, and international trade organizations.

Future Challenges and Research Directions

As avian influenza continues to pose a threat to both animal and human health, ongoing research and preparation are essential. Future challenges and research directions include:

• Developing more effective vaccines for both poultry and humans
• Improving rapid diagnostic techniques for early detection
• Enhancing surveillance systems to monitor virus evolution
• Studying the ecological factors influencing virus transmission
• Strengthening global cooperation in disease prevention and control

What are the most promising areas of research in combating avian influenza?

Some of the most promising areas of research in combating avian influenza include:

1. Development of universal influenza vaccines
2. Genetic studies to understand virus mutation and adaptation
3. Improvement of biosecurity measures in poultry production
4. Advanced modeling techniques to predict outbreak patterns
5. One Health approaches integrating human, animal, and environmental health

These research directions aim to enhance our understanding of avian influenza and improve our ability to prevent and respond to future outbreaks effectively.

Avian Influenza – PAHO/WHO | Pan American Health Organization

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Epidemiological alerts and updates 

Avian influenza, also known as ‘bird flu’, is a disease primarily affecting birds and is caused by a virus of the Orthomyxoviridae family.

According to its subtype, it may be classified as high or low pathogenicity, presenting different symptoms in infected birds. The Low Pathogenic Avian Influenza Virus (LPAIV) can cause a mild illness, often unnoticed or without any symptoms. The Highly Pathogenic Avian Influenza Virus (HPAIV) caused by subtypes (H5 and H7) of type A, causes serious illness in birds that can spread rapidly, resulting in high death rates in different species of birds.

Most of the influenza viruses circulating in birds are not zoonotic. However, some HPAI strains have the ability to infect humans, posing a threat to public health. The main risk factor is the direct or indirect exposure to infected animals or environments and surfaces contaminated by feces.

Transmission

The most common way for the virus to enter a territory is through migratory wild birds. The main risk factor for transmission from birds to humans is direct or indirect contact with infected animals or with environments and surfaces contaminated by feces. Plucking, handling infected poultry carcasses, and preparing poultry for consumption, especially in domestic settings, may also be risk factors. 

Symptoms

When avian influenza is transmitted to humans, symptoms in people can range from mild upper respiratory tract infection (fever and cough) to severe pneumonia, acute respiratory distress syndrome (difficulty breathing), shock, and even death.

Fact sheet

The emergence of pathogenic infectious diseases in the past twenty years and recent outbreaks of zoonotic diseases have increasingly drawn public attention to the fact that diseases move back and forth among species. Of the 1,415 known human pathogens, 61% are zoonotic. Among other things, it is estimated that the increase of emerging and reemerging livestock disease outbreaks around the world since the mid-1990s has cost the world $80 billion. A major factor in the emergence of new zoonoses is the closer contact with wildlife of both humans and their domesticated animals, caused in particular by increasing encroachment into wildlife habitats. Other general factors include environmental changes, globalization of food production and trade, microbiological adaptation, and human behavioral factors. 

The globalization of travel and trade and faster exchanges of people and products between countries allow for rapid dissemination of infectious diseases from their initial focus. It is difficult to estimate the burden of zoonoses on human health, particularly because endemic infections are largely under-reported around the world. It is undeniable, however, that emerging zoonoses have both direct (in terms of morbidity and mortality) and indirect (in terms of their impact on public health practice and structure) implications on public health.

PAHO Response

The Pan American Health Organization (PAHO), has drafted a strategic and operational plan to support Member States in responding to pandemic influenza, based on WHO’s preparedness plan. PAHO has a long tradition of collaborating on health and agriculture through the organization of the Ministerial Level Inter-American Meeting on Health and Agriculture (RIMSA). Every two years, PAHO discusses agreements with agriculture organizations such as the IICA, and joint activities with the veterinary services in countries for the elimination of foot-and-mouth disease, zoonoses, and food safety. In particular, the RIMSA meeting, which has been organized by PAHO for more than 20 years, provides a unique regional forum that brings together the highest level of representatives from the health and agriculture sectors along with the participation of the private sector to discuss themes of common interest. 

PAHO’s strategic and operational plan for responding to pandemic influenza includes guidelines for each phase of the potential pandemic. In particular, it includes in the pre-pandemic phase the necessary characteristics of an assessment of the countries’ capacity in responding to the threat. This assessment should involve the participation of all sectors concerned with the preparedness to a possible human pandemic, including human and animal surveillance, health services, zoonosis, agriculture, disaster, civil defense, and communication.

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16 Mar 2023

PAHO seeks to strengthen regional avian influenza surveillance and response

17 Jan 2023

PAHO issues alert on outbreaks of avian influenza in birds in ten countries of the Americas

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Avian Influenza – Causes, Symptoms, Treatment, Diagnosis

The Facts

Avian influenza, more commonly called “bird flu,” is a type of influenza or “flu” that occurs in all species of birds. The virus that causes avian influenza exists naturally in many wild birds, including wild waterfowl, without causing the condition in them (these birds are called carriers). The virus is usually associated with birds raised on poultry farms.

Most people may not immediately make the connection between avian influenza and humans. Avian influenza is rare in humans. When it does infect a human, the virus often causes serious illness or death.

Avian influenza has been getting increasing worldwide attention from medical authorities. A new subtype of the virus called H5N1, which first infected chickens and then humans in Hong Kong in 1997, can cause disease with a high rate of mortality (death) in humans.

Causes

Bird flu is caused by a virus. There are several different subtypes of the virus that have been known to cause the condition in people, including H7N9 and H5N1. The letters H and N in the subtype name stand for proteins found on the surface of the virus that are used to distinguish between different subtypes.

Pathogenicity is a measure of how likely a virus is to cause disease. In the case of the bird flu virus, it can have either low or high pathogenicity. Different subtypes of the virus cause either a mild form of the condition or an extremely contagious and highly dangerous form that spreads quickly.

Influenza viruses are constantly changing their genes. This process is called mutation.

These gene changes determine whether the virus will cause a mild condition or a deadly condition in the infected person or animal. The bird flu virus that affects birds has at least 15 different subtypes and usually only affects the bird population. The most dangerous subtype is the H5N1 subtype.

When the virus is found in humans, it is said to have “jumped the species barrier.” This means that the virus has mutated in a way that allows it to cause the condition in humans. Because humans have no natural protection or immunity to the virus, they are likely to become ill very quickly and possibly die due to complications of the bird flu.

Bird to human transmission: Birds such as turkeys, geese, and domestic chickens come in contact with the virus from food, water, or particles contaminated with the virus. The virus can be shed in the droppings of migratory birds since they are natural carriers and is able to survive for 3 months in cool temperatures. It can also survive in water at 0°C for more than 30 days and at 22°C for up to 4 days. Transmission of the virus from birds to humans occurs when a person working closely with these animals inhales dust particles containing the virus or by other means.

In countries where live birds (e.g., chickens, geese, turkeys) are sold in markets along with pigs or raised near pigs, the possibility of the virus recombining with other subtypes is greater. This is because both human and avian viruses can infect pigs. If a pig is infected with both viruses at the same time, different parts of the avian and human viruses can mix with each other. Later, the avian virus that has picked up some genes from the human form of the influenza virus is able to more easily cause the condition in humans.

Human to human transmission: Although the vast majority of human cases of bird flu are the result of direct contact with an infected bird, rare cases of direct human-to-human spread have been reported.

Symptoms and Complications

Symptoms of the condition in birds depend on the pathogenicity of the virus that infects a bird. A virus that is not highly pathogenic causes mild illness. This form of the condition produces ruffled feathers or a decrease in egg production in infected birds. The highly pathogenic form of the virus can kill so quickly that once the virus enters the bird, the bird may die the same day.

In humans, bird flu causes symptoms similar to the typical flu. People may complain of any of the following:

• aching muscles
• cough
• fever
• sore throat
• eye irritation

The symptoms usually appear within 1 to 5 days after contact with the virus.  The condition may be life-threatening because of the complications that can occur. These include viral pneumonia and extreme difficulty breathing.

Making the Diagnosis

A doctor can perform tests that identify the flu virus by swabbing the nose or throat.  If you have recently travelled to an area of the world where avian flu occurs and have any of the symptoms of the flu, you should see your doctor.

Be sure to tell the doctor where you have visited and whether or not you were at a farm or open market with live animals.

Treatment and Prevention

There are treatments to help those with bird flu.  Neuraminidase inhibitors (e.g., oseltamivir, zanamivir) is the class of medication that has been shown to be effective in reducing bird flu-related deaths.

There is no preventative vaccine for bird flu currently available to the public. However, there is a vaccine that is reserved in stockpiles by the government in case of a pandemic.

Preventing the spread of bird flu is a global effort. Steps taken to prevent the disease or stop the spread of disease include:

• destroying birds carrying or suspected of carrying the virus: When the virus is detected in birds, the priority is to quickly reduce the chance of spreading the disease to humans by detecting and destroying infected and exposed birds. The virus dies if heated at 56°C for 3 hours or 60°C for 30 minutes.
• disinfecting farm equipment, clothing, and boots: Boots, other farm equipment, and even rodents can act as vehicles that move the virus from farm to farm. Removing the virus from areas of infection requires the use of disinfectants like formalin and iodine compounds.
• limiting, restricting, or banning the shipment of live birds within and between countries that have had bird flu epidemics: Spread of the virus from farm to farm is possible due to the virus being excreted in bird droppings. Quarantine of farms is necessary to reduce the spread of the disease.

There are ways to protect yourself from catching the bird flu. People who are travelling in areas where the bird flu has occurred need to take special precautions to reduce the chance of exposure to the bird flu virus. Keep these tips in mind when travelling:

• Get a flu shot. It won’t prevent avian influenza, but it can prevent some strains of human influenza. This helps avoid the situation of becoming infected with both avian and human influenza at the same time. Having both infections increases the risk that the avian and human viruses will share genes, leading to potentially dangerous virus mutations.
• Avoid small farms where birds are grown in large numbers.
• Avoid raw eggs and foods made with eggs (e.g., mayonnaise, ice cream).
• Avoid open-air markets.
• Use alcohol-based hand sanitizer or wash your hands with soap and water frequently.

All material copyright MediResource Inc. 1996 – 2023. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Source: www.medbroadcast.com/condition/getcondition/Avian-Influenza

Highly pathogenic avian influenza – Official website of the Administration of St. Petersburg

Highly pathogenic avian influenza (HAI) is a highly contagious viral disease of birds, characterized by damage to the circulatory and central nervous systems, respiratory organs, digestion, excretion and egg production.

Clinical signs of AIV are a decrease in productivity, depression, refusal of food and water, ruffled plumage, cyanosis of the skin, swelling of the intermaxillary space, the presence of subcutaneous hemorrhages on the limbs, impaired coordination of movements, sinusitis, rhinitis, conjunctivitis, diarrhea.

Possible asymptomatic disease in AIV vaccinated birds and wild waterfowl.

The causative agent of disease is an RNA virus belonging to the orthomyxovirus family, influenza A virus genus, and its serotypes H5 and H7.

The source of pathogen is sick birds, their secrets and excretions. The reservoir of the pathogen in nature is wild waterfowl.

Exciter transmission is carried out by alimentary and contact routes. An aerogenic route of transmission of the pathogen is possible.

Transmission factors of the pathogen are droppings, feed, water, equipment, personnel clothing and footwear, bedding, vehicles and other environmental objects contaminated with the pathogen.

Bird flu also affects humans.

On the territory of the Russian Federation, cases of avian influenza are registered.

The territory of Saint-Petersburg is free from HPAI of birds.

On the territory of St. Petersburg, bird testing for HPAI is carried out in accordance with the plan of anti-epizootic measures.

Bird owners must comply with the following requirements:

– provide birds for inspection according to the requirements of state veterinary service specialists;
– notify specialists of the state veterinary service about all cases of disease or death of birds, as well as changes in their behavior, indicating a possible disease of birds with HSV;
– take measures to isolate suspected birds and dead birds;
– to comply with the requirements of the specialists of the state veterinary service to carry out anti-epizootic and other measures on the farm where birds are kept;
– use heat-treated feed for feeding birds used to obtain poultry products;
– ensure the protection of premises in which birds are kept (hereinafter referred to as the poultry house) from the penetration of wild birds, including synanthropic birds, and rodents;
– comply with the conditions, prohibitions, restrictions due to the status of the region in which the farm is located, in accordance with the Veterinary Rules for the regionalization of the territory of the Russian Federation, approved by order of the Ministry of Agriculture of Russia dated December 14, 2015 N 635.

measures in accordance with the Veterinary Rules for the implementation of preventive, diagnostic, restrictive and other measures, the establishment and lifting of quarantine and other restrictions aimed at preventing the spread and eliminating foci of highly pathogenic avian influenza, approved by order of the Ministry of Agriculture of Russia dated March 24, 2021 N 158.

Inform the State Veterinary Service of all cases of bird disease, including suspected HSV.
Contact phones: 527-50-43, 527-09-46, 374-98-12, 717-52-10, 374-98-14

Bird flu in humans

It was first discovered in 1878. With the discovery of the viral nature of the disease and the establishment that the causative agent is an influenza virus, the disease was first called avian influenza, and then avian influenza.

For a long time it was believed that only animals can get sick, and humans are not susceptible to the virus. However, in 1997, the first cases of human infection with avian influenza were reported in Hong Kong. The disease was extremely difficult, more than half of the patients died. In most cases, the virus is transmitted to humans from infected birds, but cannot spread between people. But, it is possible that as a result of mutations, the virus can gain the ability to be transmitted from person to person.

What is bird flu?

Avian influenza is an acute infectious disease of birds transmitted to humans, characterized by acute febrile syndrome, lung damage and high mortality.

The causative agent is the influenza virus type A (H5N1, H5N2, etc.).

It is pathogenic to humans.

Directly infects a person.

It affects the brain, liver, kidneys and other organs.

Resistant to the antiviral drug rimantadine.

It is more stable in the environment than the human influenza virus (in bird droppings it survives up to 3 months, in water – 4 days, at a temperature of ⁰ C – more than a month).

It tolerates low temperatures well, easily dies under the influence of disinfectants.

It has a high variability and contagiousness.

The main reservoir of bird flu in nature is migratory waterfowl (wild ducks), domestic birds (geese).

How does the avian influenza virus enter the human body?

When in contact with infected birds (for example, in poultry farms, poultry farms, personal farmsteads).

From bird droppings through dirty hands and objects.

Symptoms of avian influenza in humans.

Bird flu in humans can also occur as a mild infection of the SARS type and end in recovery. In severe cases, pneumonia develops, septic shock and respiratory failure join, which can lead to death.

The incubation period for influenza A (H5N1) lasts 2-3 days, but can last from 1 to 7 days.

The onset of the disease is acute. Body temperature rises to 39 ^about C. The feverish period lasts up to 12 days.

Chills, muscle and joint pain, headache are characteristic.

On the 2nd or 3rd day of illness (high), there are signs of rhinitis, a cough with sputum (there may be blood in the sputum), a sore throat, and bronchitis develop.

When the gastrointestinal tract is affected, diarrhea, vomiting, and abdominal pain are noted.

Some patients develop liver and kidney damage.

In most cases, there are signs of damage to the nervous system, there may be impaired consciousness, the development of encephalitis.

Complications of infection:

development of viral pneumonia.

Damage to the liver, kidneys, hematopoietic organs.

Risk factors for the development of complicated forms of the disease:

Age of the patient (children under 5 years old and adults over 60 years old)

Late hospitalization

The presence of chronic diseases, diabetes and heart disease.

Timely diagnosis and timely treatment increase the chances of recovery.

When the diagnosis is confirmed, treatment is carried out in a hospital in a boxed department. During the entire period of illness, the patient must strictly follow the recommendations of the doctor, bed rest, a diet rich in vitamins, and drink plenty of fluids. Drug therapy is prescribed only by a doctor.

Prevention of avian influenza in humans.

Get up to date flu vaccinations.

On infected farms, completely destroy the number of birds. Persons carrying out the destruction must work in overalls and respirators.

From the affected regions, the export of eggs and poultry is prohibited.

Carry out constant sanitary and epidemiological control of birds, both on farms and private farms.

Do not come into contact with wild and domestic birds that have signs of illness (puffiness, lowered head, discharge from the nostrils, lethargy).

Warn children about the dangers of touching such birds.

Do not touch or eat the meat of dead birds.

Notify local veterinarian of bird deaths.

Meat and eggs of birds must be thoroughly cooked before consumption.

Meat and semi-finished products from poultry meat should be stored in the refrigerator separately from other products.

If, after contact with an infected bird, symptoms of SARS appear, consult a doctor, be sure to inform him of the former contact.

General measures to prevent influenza during an epidemic.

Wash your hands often and thoroughly.

Try to be less frequent in crowded places (public transport and other places). If this is not possible, use a medical mask.

Adhere to a healthy lifestyle (good sleep, healthy food, sufficient fluids, physical activity).

Ventilate and humidify indoor air regularly.

Avoid hugs, kisses, and handshakes when meeting.