HPAI A(h5) Cause Illness and Death in Domestic Poultry, Human Infections With HPAI A(h5) Bird Flu Viruses Can Occur.
Ancestors of these HPAI A(H5N1) viruses first emerged in southern China and led to large poultry outbreaks in Hong Kong in 1997, which resulted in 18 human infections. The outbreak was controlled, but the HPAI A(H5N1) virus was not eradicated in birds and re-surfaced in 2003 to spread widely in birds throughout Asia, and later in Africa, Europe, and the Middle East, causing sporadic human infections. HPAI A(H5) viruses were detected in North America in 2014 causing widespread poultry outbreaks and wild bird mortality events in Canada and the United States before disappearing in 2016.
Since 2003, 19 countries have reported 864 human infections and 456 deaths with HPAI A(H5N1) virus to the World Health Organization (WHO) as of January 21, 2022. The most recent human infection with HPAI A(H5N1) virus was reported in the United Kingdom in January 2022external icon in association with exposure to domestically kept infected birds.
Risk of Infected birds shed avian influenza A viruses in their saliva, mucous and feces. Human infections with bird flu viruses can happen when enough virus gets into a person’s eyes, nose or mouth, or is inhaled. People with close or prolonged unprotected contact with infected birds or contaminated environments may be at greater infection. Illnesses in humans from avian influenza A virus infections have ranged from mild (e.g., eye infection, upper respiratory symptoms) to severe illness (e.g., pneumonia) resulting in death. The spread of avian influenza A viruses from one sick person to another is very rare, and when it has happened, it has not led to sustained spread among people YET.