Robert Roos  News Editor

Jan 23, 2004 (CIDRAP News) – Thailand and Cambodia joined the list of countries affected by highly pathogenic avian influenza today as both human and poultry cases were confirmed in Thailand and a poultry outbreak was reported in Cambodia.

The World Health Organization (WHO) said influenza A(H5N1), which recently killed five people in Vietnam, has been confirmed in two Thai boys, aged 6 and 7. And the World Organization for Animal Health (OIE) posted a report of highly pathogenic avian influenza A(H5) in hens at one farm in Supanburi province in Thailand. A report in the Bangkok Post today said the boys had "direct contact with infected chickens," but the WHO statement didn"e;t say how the boys were exposed.

A Reuters report said the Cambodian government has confirmed an outbreak of avian flu at a farm on the outskirts of Phnom Penh, the capital. A laboratory in Paris identified the virus in chickens from the farm, the report said.

Thailand and Cambodia joined Vietnam, South Korea, and Japan on the list of countries recently struck by H5N1 avian influenza. Until today, Vietnam was the only country with confirmed human cases. Taiwan recently had an outbreak of low-pathogenic avian influenza caused by an H5N2 virus.

The WHO said the two Thai boys, from different provinces, became ill early this month and later suffered acute respiratory distress syndrome. A Reuters report said the boys were in "critical but stable" condition today. The disease has mainly affected children; four of the five Vietnamese known to have had the virus were children.

A chicken butcher who was one of six Thais being tested for the avian flu died of pneumonia today, but it was not yet known if he had the disease, according to Reuters and Associated Press (AP) reports.

A report on the poultry outbreak in Thailand was submitted to the OIE by Dr. Yukol Limlamthong of the Ministry of Agriculture and Cooperatives in Bangkok. The report, posted on the OIE"e;s Web site today, said the disease killed 6,180 hens and forced the sacrifice of another 60,170 on one farm. The disease was first noticed Jan 20, and the National Institute of Animal Health provided laboratory confirmation today. The source of the infection was listed as unknown.

Today"e;s developments seemed to justify concerns voiced yesterday by the WHO that the avian flu, already present in several countries, could be more widespread than believed. The agency fears that the H5N1 virus, by crossing into humans, could combine with another flu virus and produce a dangerous new strain that could spread easily from person to person. All the human cases so far are believed to have resulted from contact with poultry.

About six million chickens in central Thailand have died or been sacrificed in recent weeks because of a disease that the government has identified as a combination of fowl cholera and non-influenza respiratory disease. Officials have denied rumors that the disease was actually avian flu. At this writing there were no reports that the government was revising its position on that outbreak.

The United Nations Food and Agriculture Organization (FAO) expressed alarm over the outbreaks in Thailand and Cambodia. "This confirms FAO"e;s concern that the spread of bird flu is taking on a large-scale regional dimension," He Changchui, FAO chief for Asia and the Pacific, was quoted by news services as saying.

Confirmation of the avian flu was an economic blow to Thailand, which is said to be the world"e;s fourth largest poultry exporter. News services said the European Union, Japan, and the Philippines immediately banned Thai chicken products.

In other news, WHO officials said a vaccine developed for the H5N1 virus that infected people in Hong Kong in 1997 and 2003 won"e;t work on the H5N1 strain circulating in Asia now, according to a New York Times report today. The virus has mutated enough so that last year"e;s vaccine won"e;t be effective against it, WHO officials said.

Dr. Klaus Stohr, a WHO flu expert, told the Times that birds in the current outbreak have been shedding large amounts of virus in respiratory secretions, whereas in the past they shed it only in feces.