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Avian influenza
Avian influenza is a contagious viral disease that mainly affects domestic birds such as chickens, turkeys, and ducks. Some strains can be very severe and spread rapidly within flocks. It is also a zoonosis, meaning it can in rare cases be...
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 severe and spread rapidly within flocks. It is also a zoonosis, meaning it can in rare cases be transmitted to humans.
The disease is caused by influenza type A viruses, which naturally circulate among wild birds, particularly migratory waterfowl. These viruses exist in different strains, some low pathogenic and others highly pathogenic.
Free-range farms or those located near wetlands frequented by migratory birds are more exposed. High bird density, lack of hygiene measures, and uncontrolled exchanges between farms also increase the risk of spread.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Affected birds may show a sudden drop in egg production, marked lethargy, breathing difficulties, and swelling of the head. In severe forms, high and rapid mortality is observed within the flock. Some mild cases may go almost unnoticed.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Transmission
The virus spreads between birds through direct contact with respiratory secretions or contaminated droppings, as well as through contaminated equipment or water. Contact with migratory wild birds plays an important role in spreading the virus to flocks. 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.
If suspicious signs appear in poultry, it is essential to promptly contact a veterinarian or the official veterinary services, without handling the sick birds. Only a professional can assess the situation and guide appropriate measures.
Prevention
Prevention relies on strict biosecurity measures: limiting contact with wild birds, disinfecting equipment and premises, and controlling the movement of animals and people on farms. Any abnormal mortality should be promptly reported to the relevant veterinary authorities.
References
WOAH — Organisation mondiale de la santé animale (ex-OIE)
OMS — Organisation mondiale de la santé
Content reviewed by the TunisieVet editorial team · Updated 08 August 2026
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This information is provided for educational purposes only and is not a substitute for a veterinary consultation. If you have any concerns about your animal's health, consult a veterinarian.
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