Nigerian health officials say a deadly strain of bird flu has been detected for the first time in the southwestern state of Ogun.
Officials Saturday said H5N1 was found at a single farm in that state. They said further testing and decontaminating processes are under way.
Health experts fear the disease could spread from Ogun to nearby Lagos, home to more than 13 million people.
Also Saturday, Poland confirmed a second outbreak of H5N1 among wild birds. The nation's chief veterinary officer told reporters that a dead infected swan was found in a western town bordering Germany.
In recent days, dead swans with H5N1 were discovered in the central Polish town of Torun.
Avian flu has spread from Asia to Europe, Africa and the Middle East. The World Health Organization says bird flu has killed 97 people since 2003, mostly in Asia.
Some information for this report was provided by AP and Reuters.