September 7, 2023-According to a new study from the Centers for Disease Control and Prevention Worldwide, the number of reported outbreaks of avian influenza in animals and infections in humans is increasing. Between 2013 and 2022, animal outbreaks and human infections with avian influenza not only increased in number, but were also found in larger geographic areas and in an increasing number of different categories of animals. These findings are particularly important in the context of sporadic outbreaks of H5 avian influenza in farmed and commercial poultry and wild birds, as well as certain mammals, globally and in the United States, with 1 human case reported in the United States and others elsewhere in the world.
The study’s authors analyzed outbreaks of avian influenza in animals around the world reported to the World Organization for Animal Health. Human avian influenza virus infections reported to the World Health Organization (WHOSA) and other animal health authorities Between 2013 and 2022. They compared these findings with notifications from 2005 to 2012.
Here are some conclusions from the study:
- The number of reported avian influenza outbreaks has increased. Categories of animals involved in avian influenza outbreaks include wild birds, captive birds, birds in live bird markets, farmed and commercial poultry, and non-human mammals such as mink.
- From January 2013 to June 2022, more than 21,000 animal avian influenza outbreaks and more than 2,000 human infections with avian influenza viruses occurred globally, and 34 avian influenza virus subtypes were reported.
- On average, 42 Member States report animal outbreaks of avian influenza each year.
- Avian influenza virus infections are reported in an average of four Member States each year.
- A total of 16 avian influenza virus subtypes were detected; 10 of these are highly pathogenic avian influenza (HPAI) virus subtypes found in animals, including birds (almost twice the number of subtypes discovered in the past eight years). times).
- Six low-pathogenic avian influenza (LPAI) virus subtypes were first reported between 2013 and 2022 in animals, including birds.
- Four HPAI H5 virus subtypes account for almost 90% of reported animal outbreaks: H5N1 (47%), H5N8 (32%), H5N2 (6%), H5N6 (4%).
- Since 2017, H5N8 has been the virus subtype causing the most outbreaks in animals globally each year (except in 2019 and 2022).
- From 2013 to 2022, 26 member states reported first outbreaks of animal avian influenza.
- Before 2013, eight member states had not reported any human cases.
- Avian influenza viruses also spread to other categories of animals.
- Between 2016 and 2022, an average of 14% of monthly reported outbreaks belonged to different animal categories, with wild birds accounting for the highest proportion (37%).
In terms of transmission, increases in geographic range and animal categories may be attributed to increases in poultry production and trade, increased contact with wild birds due to repeated annual migrations of infected birds, and migration due to climate change and land conversion Pattern changes. Agricultural Production. These increases may also better reflect avian influenza surveillance and reporting systems.
The spread of avian influenza viruses among birds, animals, and humans may have important public health implications. As animal epidemics increase, transmission to humans may also increase, and the chance of avian influenza virus recombination may also increase, which may increase its transmissibility. The most effective surveillance for avian influenza is comprehensive surveillance, including all virus subtypes, in addition to prompt notification of cases in poultry and wild birds, humans, and preferably non-human mammals, especially pigs, as pigs may be involved in avian influenza Play an important role. Plays a key role in the recombination of new influenza viruses. Efficient and sustained human-to-human transmission can lead to an influenza pandemic.
While H5N1 avian influenza, recently detected in U.S. poultry and wild birds, is not currently considered to pose a high health risk to the public, human infection is possible. As of August 9, 2023, avian influenza has affected more than 58.7 million poultry and more than 7,100 wild birds in the United States. Although one human case of H5N1 infection has been identified in the United States, CDC continues to help monitor for other infections in people who come into contact with infected birds. To date, more than 6,500 people in the United States who have been exposed to H5N1-infected birds/poultry have been monitored or are being monitored for symptoms.
The trends highlighted in this report demonstrate growing concern about avian influenza and underscore the importance of continued surveillance and timely reporting of animal and human avian influenza cases in the United States and around the world.