In pictures: Nigeria bird flu

The deadly strain of the H5N1 bird flu virus was first confirmed in poultry in northern Nigeria on 8 February 2006, although birds had been dying for weeks.

The virus was found at a commercial chicken farm in Jaji, near the city of Kaduna. Other cases have since been detected in the two neighbouring states of Kano and Plateau.

The government has ordered a cull of all infected birds and implemented measures to halt the spread of the virus - imposing a quarantine and restricting animal movement.

Some farmers have been angered by the government's handling of the outbreak, saying the response was too slow and compensation too low.

Millions of Nigerians rely on poultry as a basic source of income. People rushed to sell sick or dead chickens at market before restrictions were imposed.

No human cases of bird flu have been found in Africa, although Nigerian chicken farmers are being screened.

It is not clear how the virus has spread to the country. Some experts blame illegal poultry imports, others migrating birds. There are fears the virus will spread to other African nations.