Avian Influenza

Written by Dr. Balkar Bains

What is Avian Influenza?

Avian Influenza, sometimes known as Fowl plague, is a highly infectious disease. Characteristic signs of the infection include subcutaneous haemorrhages, cyanosis of the head region, a significant high morbidity and mortality with compromised respiratory and nervous systems.

Influenza virus naturally infects ducks, however, chickens, turkeys, geese, quail and a wide variety of wild birds including water and sea birds are susceptible to the infection. 

Where has it been detected?

Avian Influenza virus has been detected intermittently in most countries around the world since it was discovered but the disease incidence is sporadic. The virus spreads readily between poultry houses and farms by people, contaminated equipment/vehicles, and movement of infected chickens.

Clinical Signs of Avian Influenza

Clinical signs Avian Influenza may vary depending on the virulence of the virus strain. In the case of more virulent virus strains infecting susceptible chickens, the incubation period is very short, between 2 to 4 days.  The virus spreads rapidly in a flock, the course of the disease is short and mortality may exceed 50%. On observation, oedema and blue colouration develops around the head region especially the comb, wattles and skin surrounding the eyes. 

In case of a less virulent virus infection, difficulty in breathing may be the predominant signs of the disease.  Other signs typically include reduced feed intake, depression, coughing, sneezing and neurological deficits.


In cases where clinical signs are suggestive of Avian Influenza infection, it is important that the entire flock is immediately isolated.  

Avian Influenza is a notifiable disease and the presumptive diagnosis needs to be reported immediately to the respective authorities (Chief Veterinary Officer) for further investigation and confirmation of diagnosis and action.  A confirmed diagnosis will result in depopulation of the infected flock and appropriate sanitation of the farm.

Zamira is an Australian animal health company with a mission to improve the health, wellbeing and productivity of animals across the world. Read more about us here.

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