Nigerian authorities yesterday informed world health officials of an outbreak of bird flu at a large commercial farm in the northern state of Kaduna, redflaging the world that the deadly H5N1 strain of bird flu has spread to Africa.

As in Asia, many of birds are kept in free-range backyard farms as sources of income and food in Africa. (Photo: AFP)

Tens of thousands of caged birds died on the site. A laboratory in Padova, Italy, has confirmed the presence of the H5N1 strain in a dead bird from the facility.

Nigerian officials have culled thousands of birds, enacted farm quarantines, and curbed poultry shipping in attempts to check the outbreak.

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

VietNamNet/Xinhuanet