WHO confirms Vietnam bird flu case
Health experts warn that the bird flu virus will be the most likely cause of the next human flu pandemic.
HANOI, Vietnam (CNN) -- The World Health Organization has confirmed a report that a 42-year-old man is suffering from bird flu and is being treated in a hospital in Hanoi, Vietnam.
The man's older brother, a 46-year-old resident of Thai Binh Province, died on January 9 from bird flu, the WHO said in a written statement.
Initial reports said that the older man did not have the influenza A (H5) virus.
The organization had said earlier this week it was aware of the report of the 42-year-old man's infection and was seeking confirmation from the Ministry of Health.
He apparently had been caring for his older brother, who was treated at the same Hanoi hospital. The younger man first developed symptoms on January 10, nine days after his brother fell ill, the WHO said.
"The investigation surrounding the new cases is considering two hypotheses," the statement said.
"The first one includes the possibility that the 42-year-old man may have acquired his infection from his brother. All evidence to date suggests that isolated instances of limited, unsustained human transmission can be expected from avian influenza viruses in humans."
The second hypothesis is focusing on a family meal in which a dish containing raw duck blood and raw organs was served, possibly suggesting a direct poultry-to-human transmission, officials said.
Close contacts of the two men have been under supervision and no cases of the respiratory illness have so far been detected among them, the WHO said.
The two cases bring to 35 the number of laboratory-confirmed cases of avian flu in Vietnam in the past year. Of them, 27 have proved fatal, including an 18-year-old woman from Tien Giang Province who died on Wednesday.
Thailand has reported 17 cases within the past year, 12 of them fatal, the WHO said.
Avian influenza is an infectious disease of birds caused by type A strains of the influenza virus. The disease, which was first identified in Italy more than 100 years ago, occurs worldwide.
The first known infection of people with an avian influenza virus occurred in Hong Kong in 1997, when the H5N1 strain caused respiratory disease in 18 people, six of whom died. Investigators found that close contact with live infected poultry was the source of the human infection.
WHO officials credit swift destruction of Hong Kong's flocks with possibly averting a pandemic.
In February 2003, an outbreak of H5N1 avian influenza in Hong Kong caused two cases -- one of them fatal -- in a family who had recently traveled to southern China.
An outbreak of H7N7 avian influenza, which began in the Netherlands in February 2003, killed a veterinarian two months later, and caused mild illness in 83 other people.
And mild cases of avian influenza H9N2 in children occurred in Hong Kong in 1999 (two cases) and in mid-December 2003 (one case).
The most recent cases occurred in January 2004, when H5N1 avian influenza virus was found to have caused severe respiratory disease in people in northern Vietnam.
Of the 15 avian subtypes of influenza virus, H5N1 is particularly worrisome to public health officials because it mutates quickly and has been proven to be able to acquire genes from viruses infecting other animal species. It can also cause severe disease in people.
The influenza pandemic of 1918-1919 caused 40 million to 50 million deaths worldwide. It was followed by pandemics in 1957-1958 and 1968-1969.
Experts say another influenza pandemic is inevitable