KATMANDU, Nepal — A health official says a deadly strain of bird flu virus has been found in poultry in southeastern Nepal just days after officials declared the Himalayan country free of the disease.

Agriculture Ministry spokesman Hari Dahal says workers have begun to slaughter 10,000 chickens in Sarnamati village, about 400 kilometres southeast of Kathmandu, to prevent the H5N1 virus from spreading further.

The virus first emerged in Nepal's poultry last month but no human cases have been reported.

While the H5N1 virus remains hard for humans to catch, at least 254 worldwide have died from it since 2003.

Scientists are monitoring the virus for its potential to mutate and be easily spread among humans, which could set off an influenza pandemic infecting millions.