Animal and human health officials are on high alert for a major resurgence of bird flu following a warning on Monday from the UN Food and Agriculture Organisation that a drug-evading variant of H5N1 has been detected in northern Vietnam.

Sorn San, director of the National Veterinary Research Institute at the Ministry of Agriculture, told the Post yesterday that although the new variant had not been detected in Cambodia, its appearance in a neighbouring country was cause for concern.

“We are very concerned because it had appeared in a neighbouring country,” he said.

Cambodia has banned the import of live poultry and poultry products since 2004 to prevent the spread of bird flu, Sorn San said, adding that his ministry was cooperating with the Ministry of Health to combat the disease.

Bird flu is also spread by migratory birds.

The virus can spread from poultry to people but so far there have been no cases of human-to-human transmission, Sorn San said.

Ly Sovann, deputy director of the communicable disease control department at the Ministry of Health, said officials were on high alert. He said that this year there were cases of humans contracting the disease during the rainy season, which had not happened before. Moreover, human cases were no longer contained to provinces bordering Vietnam, he said.

There have been 18 cases of humans contracting bird flu in Cambodia, eight of them this year. Sixteen cases, including all eight this year, have been fatal, according to the health ministry.  

Maria Concepcion Roces, an epidemiologist at the World Health Organisation, also noted that this year cases of humans contracting bird flu were not following the previous pattern in Cambodia. Bird flu usually occurs during the “cool, dry season” from November to March, she said. Cases of human infection by H5N1 coincide with an increase in animal outbreaks, she said. The rise in the number of cases this year, and their occurrence in months when they were not seen before, could mean that “we have more extensive outbreaks among animals now”, she said.

There have been only three confirmed outbreaks of bird flu among poultry in Cambodia this year, according to the agriculture ministry.

Roces said human cases were “the tip of the problem”. The disease can be as difficult to detect among birds as it is among humans, she added, explaining that its symptoms mimic those of other diseases.

Epidemiologists around the globe are carefully monitoring the new clade, or sub-type of the H5N1 sub-type of Avian flu, detected in Vietnam to determine whether it is more lethal or more easily transmissible, she said.

“On the human side we have no indication of any change in the characteristic of the virus. It shows no increased transmissibility among humans,” she said.

She also said that testing of the virus from the last two or three people to die from it here had not yet been completed. Officials are working to raise awareness among clinicians to better detect the disease and among the public to prevent transmission, she said. “Don’t forget about bird flu. It’s still here. We don’t want people to be complacent,” Roces said.