Avian influenza

What is it?

Avian influenza is a contagious viral disease that mainly affects domestic birds such as chickens, turkeys and ducks. Some strains can be very serious and spread quickly on farms. It is also a zoonosis, which means that it can in rare cases be transmitted to humans.

Commonly observed signs

These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.

Causes and risk factors

The disease is caused by influenza type A viruses, capable of circulating naturally in wild birds, particularly migratory aquatic birds. These viruses exist in different strains, some low pathogenic and others highly pathogenic.

Farms in the open air or near wetlands frequented by migratory birds are more exposed. A high density of birds, a lack of hygiene measures and uncontrolled exchanges between farms also increase the risk of spread.

Transmission

The virus is transmitted between birds through direct contact with contaminated respiratory secretions or droppings, as well as through contaminated equipment or water. Contact with migratory wild birds plays an important role in the spread to farms. Transmission to humans remains rare and usually occurs after close contact with infected birds.

Diagnosis and care

Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.

Prevention

References

WOAH — Organisation mondiale de la santé animale (ex-OIE)

OMS — Organisation mondiale de la santé

Content reviewed by the TunisieVet editorial team · Updated 18 August 2026