Health officials reported Nigeria's first cases of bird flu in humans on Wednesday, saying one woman had died and a family member had been infected but was responding to treatment.
The victim, a 22-year old woman in Lagos, died Jan. 17, Information Minister Frank Nweke said in a statement. He added that the government was boosting surveillance across Africa's most-populous nation after the infections in Lagos, Nigeria's biggest city.
The World Health Organization had no immediate confirmation.
Nigerian health officials earlier said 14 human samples were being tested. Nweke made no mention of those cases on Wednesday.
An outbreak of H5N1 bird flu hit Nigeria last year, but no human infections had been reported until Wednesday. Until the Nigerian report, Egypt and Djibouti were the only African countries that had confirmed infections among people. Eleven people have died in Egypt.
The bird flu virus remains hard for humans to catch, but health experts fear H5N1 may mutate into a form that could spread easily among humans and possibly kill millions in a flu pandemic.
Amid a new H5N1 outbreak reported in recent weeks in Nigeria's north, hundreds of kilometers (miles) from Lagos, health workers have begun a cull of poultry.
Bird flu is generally not harmful to humans, but the H5N1 virus has claimed at least 157 lives worldwide since it began ravaging Asian poultry in late 2003, according to the WHO.
The H5N1 strain had been confirmed in 15 of Nigeria's 36 states.
By September, when the last known case of the virus was found in poultry in a farm near Nigeria's biggest city of Lagos, 915,650 birds had been slaughtered nationwide by government veterinary teams under a scheme in which the owners were promised compensation. However, many Nigerian farmers have yet to receive compensation in the north of the country, and health officials fear that chicken deaths may be covered up by owners reluctant to slaughter their animals, reports AP.
Since bird flu cases were first discovered in Nigeria last year, Cameroon, Djibouti, Niger, Ivory Coast, Sudan and Burkina Faso have also reported the H5N1 strain of bird flu in birds. There are fears that it has spread even further than is known in Africa because monitoring is difficult on a poor continent with weak infrastructure.
With sub-Saharan Africa bearing the brunt of the AIDS epidemic, there is concern that millions of people with suppressed immune systems will be particularly vulnerable, especially in rural areas with little access to health facilities. Many people keep chickens for food, even in densely populated urban areas.