Questions and answers about avian influenza A (H5N1) – PAHO/WHO

“Avian flu outbreaks pose a real threat to animals and a potential threat to humans”

July 2023 (PAHO/WHO) – In January of this year, the Pan American Health Organization (PAHO) raised the alarm on the unusual detection of highly pathogenic avian influenza outbreaks in birds in countries in the Americas region and confirmed that this is a Latin American For the first time in the country, a case of human infection with H5N1 avian influenza was discovered. From then until the first week of July 2023, 16 countries have reported cases in birds and other animals, and two countries have confirmed human cases.

Dr. Cosivi, Director, PANAFTOSA

We spoke to Dr. Ottorino Cosivi, Director of the Pan American Center for Foot-Mouth and Veterinary Public Health (PANAFTOSA) of the Pan American Health Organization (PAHO) in Rio de Janeiro, about the situation with bird flu in the region and the need for coordination veterinary services and public health, and prevention and control strategies in poultry to mitigate the risk of virus transmission to humans.

What is the situation of bird flu in this area?

During 2022-2023, the Region of the Americas has been suffering from animal HPAI epidemics associated with the A(H5N1) subtype. From an evolutionary point of view, the virus belongs to a group of viruses (called clade with genetic changes similar to those circulating in Asia, Africa, Europe and the Middle East from late 2020 to 2021. At the end of the same year, the virus was also found in North America.

This epidemic results in high morbidity and mortality in domestic poultry such as hens, chicks and wild birds; it poses a real threat to animals and a potential threat to humans. As of the first week of July, 16 countries in Latin America and the Caribbean had registered cases of A(H5N1) infection in animals. A situation of this magnitude had never occurred in the region; because, while there had been cases of highly pathogenic avian influenza in previous years, mainly in North America, there was no such impact or spread in other parts of the region.

Is there concern that the virus will infect other animals besides birds?

The incidence of A(H5N1) cases in mammals and wild and domestic animals is alarming. In this case, the main concern is that the virus has shown adaptations to different species, especially mammals that may be biologically closer to humans. Therefore, it is necessary to monitor circulating viruses through existing influenza surveillance systems at the national, regional, and global levels to detect possible changes and adaptations to human transmission. Notably, this applies to other avian influenza subtypes, not just A(H5N1), as well as other zoonotic influenza, such as swine influenza.

Why is it important to monitor animal influenza and detect cases early?

Adequate surveillance for the presence of avian influenza in birds allows us to understand the subtypes of avian influenza that are circulating and, more relevant to public health, helps us understand those viruses with more pronounced zoonotic features the existence of; that is, the possibility of changes leading to greater adaptation in humans to transmission. Additionally, early detection enables countries to implement rapid responses to reduce the risk of the virus spreading to humans.

Should birds or other animals infected with bird flu be euthanized?

Today, slaughtering poultry is one of the strategies recommended by the World Organization for Animal Health (WHO) and the Food and Agriculture Organization of the United Nations (FAO) to control and eradicate the virus before it spreads. However, this is not the only tool, as it is also important to properly isolate infected areas, restrict animal movement, enhance biosecurity, and conduct rigorous surveillance in areas close to focal points. No There is a set of measures applicable to all countries, multiple strategies must be used, and each case must be analyzed in terms of animal numbers, epidemiological context and the possibility of implementing other control actions, especially when dealing with farm animals. ecological value.

Some countries around the world had started vaccinating poultry before this outbreak, while others have also started vaccinating against bird flu this year. Is this vaccine recommended for animals? Vaccination of birds against avian influenza is a tool that can help reduce clinical morbidity, reduce mortality and control transmission of the disease. However, this strategy also presents other challenges, including: selecting the most appropriate vaccine for the virus that is circulating in the country, determining the vaccination strategy (e.g., whether it is an emergency or preventive vaccination), determining who will be vaccinated Vaccines in the animal population of the vaccinated population, and adequate monitoring of this population through surveillance measures will allow us to detect any possible transmission of the virus in the vaccinated population, as well as changes in the virus within the country.

PANAFTOSA works directly with national veterinary services. How do you work with those responsible for human health?

Coordination on avian influenza issues between those responsible for animal health and public health is critical. Together with the Communicable Disease Threat Management Unit of the PAHO Health Emergencies Department, we facilitate intersectoral work on human-animal contact through regional advice and technical assistance at country level.

What is the risk of human-to-human transmission of bird flu?

Whenever an avian influenza virus circulates between domestic poultry, wild birds, or mammals, there is a risk of sporadic infection in humans, as well as the risk of small cases arising from contact with infected animals or contaminated environments. Currently, human avian influenza cases related to this H5N1 influenza outbreak have been isolated. Three human infections caused by avian influenza A(H5N1) have been reported in the region: the United States (April 2022), Ecuador (January 2023), and Chile (March 2023). In none of these cases, sustained human-to-human transmission was detected. However, maintaining and strengthening surveillance of these cases is critical, as we cannot ignore the risk of a potential pandemic caused by avian influenza viruses.

What are PANAFTOSA’s recommendations for countries to prevent or control outbreaks of avian influenza in animals?

States must have appropriate and up-to-date contingency plans in place. Other organizations such as FAO and OMSA have made specific recommendations in this regard. It is important that teams involved in animal influenza surveillance and response are trained to implement these measures in an emergency and have the necessary resources.

In addition, it is also important for poultry producers to enhance the biosecurity of their facilities to prevent contact between poultry and wild birds and the latter’s access to water and food sources.

Producers also play an important role in the early detection of disease, so they must be able to identify and report it to veterinary authorities so they can rule out or confirm cases of avian influenza and respond in a timely manner. Early detection facilitates a timely response, which in turn helps reduce the spread of the virus.

It is also imperative for individuals or families who keep birds for personal consumption to be well informed on how to recognize when a bird is infected, what to do if they suspect it, and how to adequately protect themselves.

What steps can be taken to prevent and reduce the risk of people becoming infected?

Controlling avian influenza in birds is one way to reduce the risk of transmission to humans. Any worker handling wild and poultry must have adequate biosecurity and conservation knowledge, so it is recommended that veterinary authorities, in collaboration with public health, train all those involved in poultry production, as well as wildlife workers. In addition to knowing the protocols, they must have the proper protective equipment to handle birds, including specific protective clothing designated for these tasks, as well as gloves and masks. Likewise, if a person comes across a dead, dying or diseased wild or domestic fowl, they should refrain from touching or handling it and report the situation to official veterinary authorities immediately.

What is the Pan American Health Organization doing?

The PAHO, in cooperation with countries in the region and other agencies, has strengthened surveillance of avian and human avian influenza viruses and provided technical assistance for the timely detection, treatment and investigation of cases of A(H5N1) virus infection. . The organization is also working with national veterinary and public health services to strengthen the capacity of laboratories so that they have the diagnostic capabilities necessary to determine the presence of the avian influenza virus and detect changes in its genetics.

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