The official leading the United Nations response to bird flu has warned of the consequences for Africa of the first confirmed case of the H5N1 strain in Nigeria.
David Nabarro of the World Health Organisation said the disease was unlikely to be confined to one location.
He warned that if reports of the strain among poultry elsewhere in the region were confirmed, the situation would be very severe.
The chicken that tested positive for H5N1 was taken from a commercial battery farm in the north of Kaduna state.
However, there are also reports that thousands of chickens have died in northern Nigeria from what was described as a similar infection over the past few weeks.
The Nigerian government said it would cull all chickens suspected of being infected with bird flu, compensate farmers and quarantine all suspect farms.
A South African veterinary institute has been asked to conduct tests on bird samples from Kenya, Malawi and Sudan, where FAO experts have been collecting samples.
Inspectors are reported to be already at work in the Kaduna region of Nigeria, and two other areas.
