Avian influenza

Avian influenza, or bird flu, is a disease caused by certain influenza A viruses like A(H5N1), A(H9N2), A(H7N9), and A(H5N6), which mainly affect wild water birds and poultry. It is a zoonotic illness, meaning it spreads from animals to humans. Since 2020, a highly aggressive variant of the A(H5N1) virus has been circulating globally, leading to a record number of deaths in wild birds and poultry across Africa, Asia and Europe. This severe virus has also been found in mammals since 2022.

While human infections are rare, they usually happen after close contact with infected live or dead birds or environments contaminated by them, such as live bird markets. Importantly, current animal influenza viruses have not shown the ability to spread easily or continually from person to person. The disease can be severe in people and case fatality rate is much higher than that of regular seasonal flu.

The WHO Eastern Mediterranean Region has reported sporadic human infections. In 2006, avian influenza caused by the highly pathogenic A(H5N1) influenza virus spread rapidly through the Eastern Mediterranean Region with large non-human outbreaks reported in Afghanistan, Djibouti, Egypt, Iraq, Jordan, occupied Palestinian territories, Pakistan and Sudan.

Human illness caused by avian influenza viruses can be mild, like a common cold, or as severe as acute respiratory disease. The seriousness of the disease depends on the specific virus involved and the infected person's overall health. It can be fatal in some cases. Symptoms reported in humans with A(H5N1) infection usually include fever, which is often high (above 38°C), muscle aches, cough, feeling unwell and a sore throat. Some people also report eye inflammation (conjunctivitis) or other signs not linked to the respiratory system early in the sickness. The disease can worsen rapidly, leading to major breathing issues and sometimes changes in mental state or seizures. The chance of death (case fatality rate) for those infected with A(H5) and A(H7N9) subtypes is much higher than it is for seasonal flu. The A(H5N1) virus has also been found in samples from individuals who were exposed to infected animals or contaminated environments, even if they showed no signs of being sick. Health providers in the Eastern Mediterranean Region should stay vigilant about possible avian influenza A(H5) infections to allow for quick diagnosis and reduce spread.

People who suspect they have avian influenza should contact health authorities immediately and start proper clinical care. This helps reduce the chance of severe illness and death. Patients with confirmed influenza who have serious, complicated or quickly worsening sickness should receive antiviral medicines, such as oseltamivir, right away. Doctors will often start treatment with oseltamivir even if infection is only suspected and laboratory results are not yet available. Corticosteroids should generally not be used, although they may be considered in specific severe cases, like septic shock with suspected adrenal insufficiency. Early supportive care is essential in managing the disease. This includes assessing the patient, watching oxygen levels closely, and providing extra oxygen if needed.

Seasonal influenza vaccines do not protect people from animal influenza A viruses. While certain vaccines for types like H5N1 have been developed and licensed in some countries for pandemic readiness, they are not broadly used because human cases are relatively rare.