The deadly H5N1 strain of bird flu has been found in two more Nigerian states, the Agriculture Ministry said Thursday, a day after the country reported the first known outbreak of the virus in Africa.

The strain has been confirmed at two farms in Kano state and one in adjoining Plateau state, said Tope Ajakaiye, an Agriculture Ministry spokesman. Africa's first documented case was reported Wednesday in the northern state of Kaduna. No human infections have been reported in the country.

Nigeria ordered the quarantine and killing of any fowl suspected of carrying bird flu in hopes of halting its spread, officials said.

"The federal government is doing everything to contain the disease within the three centers that have been located," Ajakaiye said in a statement.

Bird farms across northern Nigeria, Africa's most populous nation with 130 million people, are now under quarantine, and a special assessment team traveled around the region Thursday, said Junaidu Maina, director of Nigeria's livestock department. He did not say to how many of Nigeria's 36 states were under the quarantine order.

Nigeria's Agriculture Minister Adamu Bello on Wednesday confirmed findings by the Paris-based World Organization for Animal Health, known as the OIE, of an H5N1 outbreak on a commercial poultry farm in Kaduna.

The farm had a total of 46,000 chicken, geese and ostriches. About 40,000 of them died of bird flu and the other 6,000 were destroyed, according to OIE.

International experts from the U.N.'s Food and Agriculture Organization, the World Health Organization and the OIE were to travel Friday to Nigeria to help, said Alex Thiermann, an OIE expert.

Bird flu began ravaging poultry across Asia in 2003, forcing the slaughter of more than 100 million birds. The virus jumped to humans, and the World Health Organization has confirmed 88 deaths from bird flu out of a total of 166 cases of human infection. Almost all the cases have been in Asia, but the disease recently has been detected in Europe and the Middle East.

Though all the people who contracted the disease so far are believed to have been infected through contact with sick birds, experts are concerned the disease could mutate into a form easily spread from human to human, potentially triggering a global pandemic.

Indonesia said Thursday that two women from the same town have contracted the virus.

China said Wednesday that a 26-year-old woman had bird flu — the 11th known case in that country.

Sub-Saharan Africa, with about 600 million of the world's poorest people, is particularly ill-equipped to deal with a major health crisis. With weak and impoverished government institutions in regions where many people keep chickens for badly needed food, experts say any mass killings of the animals — often a first step in controlling bird flu — will be difficult to pull off.

The World Health Organization said Nigeria has a poultry population of about 140 million and that the country's overtaxed veterinary services needed international help, while calling on other African countries to act quickly against any suspected outbreaks.