Avian flu has been detected in chickens in Kampong Cham province, health officials announced on Friday, following the deaths of more than 200 chickens in one village.

Experts took two dead birds for testing after receiving reports of the die-off in Prey Chhor district’s Trapaing Preah commune in late November, according to a letter from the Ministry of Agriculture sent to Prime Minister Hun Sen on Friday. Lab testing confirmed the chickens had H5N1, the most common form of bird flu.

Bird flu outbreaks have had a human cost in the past – 14 Cambodians died during one in 2013 – but no human cases have been detected in Koh Svay village so far, according to Ministry of Health spokesman Ly Sovann. In a Facebook post, Sovann warned people to avoid eating or selling poultry that dies under mysterious circumstances and to maintain hygiene practices.

World Health Organization Cambodia spokeswoman Vicky Houssiere said the body is assisting the ministry with the outbreak.

Kim Sour Phirun, head of Kampong Cham’s Health Department, said authorities are checking nearby health centres for patients with symptoms of H5N1.

H5N1 is difficult to transmit between people, but public health experts are concerned that the virus could mutate. Humans are infected mostly through handling of infected birds.

Additional reporting by Daphne Chen