Nigeria's bird flu burden

The Conversation Africa asked Clement Meseko, an animal influenza expert and a virologist at the National Veterinary Research Institute in Jos, Nigeria, to explain the re-occurrences of avian influenza in that country.

Avian influenza, commonly called ‘bird flu’, is a highly contagious viral infection of birds that has recurred in Nigeria since 2006. It has resulted in the loss of millions of birds in the poultry industry and hence a loss of income for people who rely on it. Nigeria is currently grappling with another outbreak that started in 2021.

What is bird flu? How does it spread? Is it dangerous to humans?

Bird flu is scientifically known as avian influenza and the pathogenic form as highly pathogenic avian influenza. It is a disease in birds (specifically poultry) caused by an influenza virus. It is highly pathogenic, meaning it causes tissue and organ damage in the host, and can kill more than 75% of the infected flock.

Waterfowl such as ducks are natural reservoirs of the disease. They can harbour bird flu without showing any symptoms. Many waterfowl and other wild birds are migratory, moving across and between continents. This brings them into contact with resident birds and domestic poultry. Their body secretions and excretions may contain viruses that can infect other birds and poultry.

Symptoms in infected poultry include sudden death, respiratory distress, coughing, and haemorrhages in tissue and organs. Other animals, including pigs, horses and dogs can be infected. The disease is also zoonotic and can be fatal for humans.

The virus has the capacity to cause a pandemic. An influenza virus of avian origin, but not the currently circulating strain, caused the 1918 pandemic that ultimately killed about 50 million people, making it worse than the current COVID-19 pandemic.

How many outbreaks have there been in Nigeria since 2006?