The Ho Chi Minh City Law newspaper quoted Dong Nai province residents as saying farmers there threw at least 100 tons of chicken excrement a day into Tri An lake, whose waters flow into Dong Nai river and run through the country's biggest city.

"Dropping chicken excrement into Tri An lake during the period when bird flu is evolving into a pandemic is extremely dangerous," Le Hoang Sang, deputy director of the Ho Chi Minh City's Pasteur Institute, was quoted as saying by the newspaper.

Chicken excrement is one of the main carriers of the H5N1 virus, which can survive in a cool and wet environment for a month and slightly less if in water, he said.

In January, a 9-year-old boy died from bird flu in the Mekong Delta province of Tra Vinh after he caught it while swimming in water in which the bodies of infected poultry had been thrown.

"Throwing chicken excrement into the lake must be stopped immediately," Sang said, adding that tests of the fish food would start this week.

About seven million people in Ho Chi Minh City use water purified from the Dong Nai river, Nguyen Van Phu, director of the Saigon Water Supply Co, told the state-run Lao Dong newspaper.

"We ordered a stop to fish feeding that way when this rainy season began but it's difficult if farmers move the excrement in at night," said Vu Thi Tho, People Committee's chairwoman of La Nga commune, 115 km (70 miles) northeast of Ho Chi Minh City.

But the Lao Dong newspaper said poultry waste was still being taken to the area by truck.

Since bird flu arrived in Dec. 2003, 91 people have caught it in Vietnam and 41 have died, fanning experts' fears that the virus could mutate into a form passed easily between people and unleash a global pandemic.

(Source: Reutes)