Pigs in Vietnam have tested positive for the bird-flu virus that has infected millions of chickens and ducks across Asia and killed 18 people, the United Nations’ Food and Agricultural Organisation said on Friday.
”Nasal swabs taken from pigs have been positive for H5N1,” said Anton Rychener, Hanoi representative for the UN agency. ”It continues to be under investigation and is of concern. We’ll be bringing in an expert.”
Health officials have said the bird flu sweeping Asia is contracted through direct contact with infected birds.
But experts have said it’s possible the virus jumped to humans through a mammal, such as pigs, which have been implicated in past human flu outbreaks.
Swine are often housed with poultry in traditional family farms in Asia, and are more genetically similar to humans more than birds are.
Rychener said the pigs were tested recently in and around the capital, Hanoi. He didn’t say how many were sampled, or which laboratory processed the tests. Results on blood samples from the pigs haven’t been completed, he said.
Some health experts cautioned the tests were not conclusive and that it was much too early to start talking about culling swine.
Other rigorous tests on pigs have come back negative and the Hanoi samples may have been contaminated.
Vietnamese officials said on Friday tests done on samples taken from 179 pigs by Hong Kong laboratories showed they did not have the bird-flu virus.
”The tests of the pig samples came in negative for H5N1 strain of the bird flu,” said Nguyen Ngoc Nhien, deputy director of the Institute for Animal Health in Hanoi.
The samples were taken from pigs in bird flu-affected areas in the northern provinces of Ha Tay and Thai Binh, along with Haiphong city, and sent to the World Health Organisation’s (WHO) labs in Hong Kong last week, he said.
The institute may send more pig samples from central and southern Vietnam for testing, Nhien said.
Health officials have warned that if the bird-flu virus combines with a human influenza virus, the result could create a more lethal strain that can be passed directly between people.
”Pigs can be a mixing bowl of chicken viruses and human viruses. I wouldn’t exclude the pig yet from the whole thing,” said John Oxford, a flu expert from Queen Mary School of Medicine in London, earlier this month.
Avian influenza has killed 13 people in Vietnam and five in Thailand.
The latest fatalities from Vietnam, announced on Friday, were a six-year-old girl from southern Dong Nai province and a 24-year-old man from central Lam Dong province. The girl died on Tuesday and the man had died on Monday.
Vietnam has now reported a total of 17 cases. Besides those who died, two have recovered and been released, while a 20-year-old woman and an 8-year-old girl remain hospitalised. The WHO has not confirmed the latest deaths.
More than 17-million of Vietnam’s 250-million poultry have been slaughtered in the past month as government officials have scrambled to control the outbreak.
The country has imposed a nationwide ban on the sales of live poultry and poultry products, as well as the transport of fowl.
But officials have stopped short of ordering the slaughter of the country’s entire poultry stock.
However, authorities in Hanoi this week ordered the culling of the city’s estimated two million chickens and ducks.
Vietnam’s largest city, the southern business hub of Ho Chi Minh City, ordered the slaughter of all of its 3,5-million poultry two weeks ago.
Minister of Agriculture and Rural Development Le Huy Ngo has said Vietnam’s economic losses from the outbreak were estimated so far at 400-billion dong ($25-million). — Sapa-AP