Bird flu: Nigeria is on major migratory bird routes, new strains keep appearing

THE CONVERSATION

Bird flu has been recurring in Africa since 2006 and Nigeria is heavily affected. High-level biosecurity measures are required to keep people and animals safe.

Avian influenza is a highly contagious viral infection of birds, commonly called “bird flu”, which has been recurring in Nigeria since 2006. It has resulted in the loss of millions of birds and income for people who rely on the poultry industry. Nigeria is currently grappling with another outbreak which started in 2021.

The Conversation Africa asked Clement Meseko, a virologist and expert on animal influenza, to explain the disease’s re-occurrences.

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.

Waterfowls like ducks are natural reservoirs of the disease. They can harbour avian flu without showing any symptoms. Many waterfowls 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 virus that can then infect other birds and poultry.

The symptoms in infected poultry include sudden death, respiratory distress, cough and haemorrhages in tissue and organs. Other animals, including pigs, horses and dogs can also be infected – and so can humans. In fact, it is zoonotic and therefore can be fatal for humans too. Highly pathogenic avian influenza H5N1 virus infections have infected more than 880 people with about 50% case fatality globally.