Jun 6, 2007 (CIDRAP News) – Officials from Indonesia's avian flu commission said today that the H5N1 avian influenza virus may have mutated in a way that makes it more transmissible from birds to humans, but a World Health Organization (WHO) official said the WHO had seen no evidence of such a change, according to news services.
Bayu Krisnamurthi, chief executive for Indonesia's National Committee for Avian Influenza Control and Pandemic Influenza Preparedness, told reporters that in the past, human infections required high-intensity and high-density exposure to the H5N1 virus, according to a Reuters report today. "There are now suspicions that this [infection] has become easier," he said, adding that a mutation has not been confirmed yet.
Wayan Teguh Wibawan, a microbiologist from Indonesia's avian flu commission, told Reuters that the suspicions are based on preliminary results of genetic tests at laboratories in Indonesia. The amino acid structure of poultry H5N1 samples is becoming increasingly similar to that seen in human H5N1 samples, he said.
The similarity in amino acid structure makes it easier for the virus to attach to receptors on cells that line the throat and lungs, Wibawan told Reuters. The virus would have to attach readily to human cell receptors in order to easily pass from birds to humans, he said.
Wibawan told Reuters he had noted "gradual changes" in the virus samples he receives each month, but he gave no other details.
However, Gregory Hartl, a WHO spokesman, told Reuters that the WHO has not seen any evidence that the virus has become more transmissible to humans.
The WHO has received very few H5N1 isolates from Indonesia recently. Hartl told CIDRAP News today that the agency has received just three Indonesian H5N1 samples, gathered from two patients, this year. "Without virus characterization, we cannot say whether the virus has changed or not," he said.
Indonesia withheld H5N1 samples from the WHO for about 5 months, starting last December, as a protest against the country's lack of access to pandemic vaccines and other pandemic medications. In mid-May, during the WHO's annual meeting in Geneva, the country's health minister announced that Indonesia had resumed sending samples to the agency. News reports at the time said the country had submitted three H5N1 samples to a WHO-affiliated laboratory.
Lo Wing-Iok, an infectious disease expert in Hong Kong, said the suspected changes in the virus show how important it is for Indonesia to share its samples with the global community, according to the Reuters report today.
"These must be confirmed and the world must be forewarned if there has been such an important change," he told Reuters. "If there is such a change, it would not only mean that the virus can jump more easily from bird to man, but from human to human, too."
Indonesia has had 99 human H5N1 cases with 79 deaths, more than any other country. WHO data show that from January through May of this year, the country had 26 cases with 21 deaths, versus 31 cases and 24 deaths for the same period in 2006. Indonesia is one of three countries, along with Egypt and Vietnam, where the H5N1 virus is endemic in poultry.
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