BEIJING China and Pakistan have announced bird flu outbreaks among poultry, a day after two women, one in China and one in neighboring Vietnam, died of the virus.
The Chinese outbreak, first noticed on February 17 in Zunyi in the southwestern province of Guizhou, had killed nearly 4,000 birds and triggered the culling of more than 238,000, Xinhua news agency said late on Monday, citing the Ministry of Agriculture.
China has reported four outbreaks of the disease in poultry since December, when average temperatures across the country hit their lowest in decades. Bird flu tends to be more active in the cold.
Experts fear the H5N1 strain could mutate or combine with the highly contagious seasonal influenza virus and spark a pandemic. With the world's biggest poultry population and hundreds of millions of farmers raising birds in their backyards, China is seen as crucial in the global fight against the disease.
Pakistani authorities found a fresh outbreak of H5N1 in chickens, the fourth case in a month, in the southern city of Karachi, a government official said on Tuesday.
Pakistan confirmed its first human death from the virus near the northwestern town of Abbottabad in December.
China has reported three confirmed human deaths from bird flu this year, the most recent in the southern province of Guangdong, neighboring Hong Kong.
The woman, a 44-year-old migrant worker, probably contracted the H5N1 virus from sick poultry she kept in her backyard, Hong Kong government health officials said.
The spate of cases is a concern for a country that has the world's biggest poultry population, many of them backyard birds roaming free. China has struggled to combat the virus with mass inoculations for birds and an education campaign for those who handle them.
State-run Voice of Vietnam radio said on Tuesday a woman teacher had died from H5N1 in the north of the country, the fourth death from the virus this year.
The 23-year-old woman died on Monday at a Hanoi hospital after falling sick as she ate chicken in her home province of Phu Tho, the radio quoted the Health Ministry as saying.
In communist-run Vietnam, official announcements are often made in state-run media.
The woman's death is the fourth out of five people infected by bird flu so far this year in Vietnam after an extended cold spell in northern provinces.
Excluding the two deaths on Monday, bird flu has killed 232 people among the 366 known cases globally, among them 50 deaths in Vietnam, the World Health Organisation has said.
(Additional reporting by Augustine Anthony in Islamabad and Ho Binh Minh in Hanoi; Writing by Nick Macfie; Editing by Sanjeev Miglani)