Confusion Over Possible H5N1 Mutations In Indonesia

Indonesia's decision to not share viral samples taken from H5N1 positive patients for more than five months would appear to be having a huge impact on determining whether or not this strain of the bird flu virus has undergone an extremely dangerous mutation :

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.