HANOI, Nov. 23 (Xinhua) -- Chickens in Vietnam's southern Tien Giang province have recently died en mass with unidentified causes, while bird flu is hitting three provinces in the northern and central regions.
Over 50,000 chickens raised in more than 10 farms in Cho Gao district died after suddenly stopping eating, according to local official on Friday.
The fowls were suspected to have died of Marek, a highly contagious viral neoplastic disease in chickens caused by a herpes virus, said Dang Van Chien, head of the district's veterinary bureau.
A number of chickens in the province's Chau Thanh district have also died recently.
Now, bird flu is hitting the two northern provinces of Ha Nam and Cao Bang, and central Quang Tri province, according to the Department of Animal Health under the Vietnamese Ministry of Agriculture and Rural Development.
Bird flu outbreaks in Vietnam, starting in December 2003, have killed and led to the forced culling of dozens of millions of fowls in the country.