HONG KONG (AP) — Hong Kong authorities say a second dead bird in a week has tested positive for a dangerous strain of bird flu, raising health concerns in the city.

The agricultural department said Friday that lab tests confirmed an Oriental magpie robin found dead on Dec. 17 was infected with H5N1 avian influenza.

On Wednesday, workers slaughtered more than 19,000 birds at a Hong Kong market and banned the import and sale of live poultry for three weeks after a chicken carcass tested positive for H5N1.

H5N1 occasionally infects people who have close contact with infected poultry, particularly in parts of Asia. Globally, 331 people have died from bird flu since it was first detected in 2003.

The Oriental magpie robin is commonly found in Hong Kong.