(Agencies)
Updated: 2004-02-13 15:17

Human victims of the bird flu sweeping Asia fell sick quickly and a high proportion of them were killed by the virulent virus, the World Health Organization said in a study of 10 cases in Vietnam.

The virulent H5N1 bird flu virus, suspected to have been spread by migrating birds, has broken out in eight Asian countries, devastating poultry flocks and killing at least 14 people in Vietnam and five in Thailand.

Six of Vietnam's human victims got sick about three days after being exposed to the virus, and out of the 10 cases studied, eight of them died about 10 days after the onset of illness, the WHO said in a report on the first clinical and epidemiological data from Vietnam.

Asia's human victims are believed to have caught the disease from contact with sick chickens, but fears persist that the virus could combine with a human flu virus and mutate into a deadly disease that could be passed between people.

Of the 10 Vietnamese victims studied, nearly all had direct contact with chickens or ducks, ranging from a boy who loved cock fighting to farmers who caught the virus after preparing butchered chickens.

Eight of the people studied by Vietnamese medical experts have died, one of them recovered and one was in critical condition, said the WHO in a report posted on its Web site at http://www/who.int.

While issuing the study, the U.N. health agency cautioned that limited infection between people could not be ruled out yet.

Two sisters who died in January from the virus were found to have only avian and no human influenza, but the WHO said that was not conclusive proof they caught it from poultry and not from their brother, who died of a respiratory illness.

"It still remains an unresolved question," said Robert Dietz, WHO's spokesman in Vietnam Friday. He said the issue may never be resolved. The brother was not tested as his body was cremated.

The WHO said main symptoms of the bird flu were a fever of more than 100.4 degrees Fahrenheit, shortness of breath and coughing.