Avian influenza (AI) is a disease caused by infection with avian (bird) influenza (flu) Type A viruses. These viruses occur naturally among wild aquatic birds worldwide and can infect domestic poultry and other bird and animal species. Avian flu viruses also can infect humans and cause disease.
AI viruses are divided into 2 groups based on their ability to cause disease in poultry: high pathogenicity or low pathogenicity. Highly pathogenic viruses result in high death rates (up to 100% mortality within 48 hours) in some poultry species. Low pathogenicity viruses also cause outbreaks in poultry but are not generally associated with severe disease.
The reported signs and symptoms of low pathogenic avian influenza (LPAI) A virus infections in humans have ranged from typical human influenza-like symptoms ( fever, cough, sore throat, and muscle aches) to lower respiratory disease (pneumonia) requiring hospitalization. Highly pathogenic avian influenza (HPAI) A virus infections in people have been associated with a wide range of illness from eye infections only, to influenza-like illness, to severe respiratory illness (e.g. shortness of breath, difficulty breathing, pneumonia, acute respiratory distress, viral pneumonia, respiratory failure) with multi-organ disease, sometimes accompanied by nausea, abdominal pain, diarrhea, vomiting and sometimes neurologic changes (altered mental status, seizures).
Avian influenza infections in birds or humans are observed in parts of Asia, Europe, the Middle East, and Africa. During an outbreak of avian influenza among poultry, there is a possible risk of infection of enough virus gets into a person’s eyes, nose or mouth, or is inhaled. This can happen when the virus is in the air and a person breathes it in, or when a person contacts with infected birds or surfaces that have the virus on them then touches their mouth, eyes or nose. With certain types of avian influenza, a human infection may occur even though there is no apparent outbreak among poultry. However, the risk from avian influenza is generally low to most people. Infection cannot result from properly handled and cooked poultry and eggs.
The most effective way to prevent avian influenza is to avoid sources of exposures such as avoid poultry farms, contact with animals in live bird markets, being close to areas where poultry may be slaughtered, and any surfaces that appear to be contaminated with faeces from poultry or other animals.
People who have had contact with infected birds may be given influenza antiviral drugs preventatively. While antiviral drugs are most often used to treat flu, they also can be used to prevent infection in someone who has been exposed to influenza viruses. When used to prevent seasonal influenza, antiviral drugs are 70% to 90% effective.