HANOI, Aug. 25 (Xinhuanet) -- Much more research, funds and time are needed to probe into identifying the transmission route of the avian influenza viruses and their possible mutation, and stamp out recent outbreaks in several Asian countries, including Vietnam.

    Hans Troedsson, representative of the World Health Organization(WHO) in Vietnam, made the remark when holding an informal meeting with local and foreign media here on Wednesday.

    "There are different researches (on avian influenza) going on in parallel. But, it is not clear about the transmission route (from poultry to humans). Much more is needed," he said.

    It is very important to find out whether avian influenza viruses change or not, he noted, stressing that if the mutation occurs, it will pose "more threat to public health."

    Dr. Richard Brown, epidemiologist from the Philippines-based Western Pacific Regional Office under the WHO, who is in Vietnam along with two other foreign experts to help the country deal with recent bird flu outbreaks, touched another danger relating to the possible transmission of avian influenza viruses from poultry to mammals like pigs.

    If a pig is simultaneously infected with both a human and an avian influenza virus, it can serve as a "mixing vessel", facilitating the exchange of genetic material between the two viruses, he said, explaining that the resulting new virus will have pandemic potential if it retains sufficient human genes to allow efficient human-to-human transmission.

    Another threat which worries both WHO experts and Vietnamese ones is the potential combination of the deadly avian influenza strain of H5N1 and the human influenza strain of H3N2, which can further damage human health.

    "Though there have been no evidence about the combination of H5N1 and H3N2, we can´t overlook this dangerous possibility. Boththe WHO and we´re afraid of the combination," Le Thi Quynh Mai, expert from the Vietnam´s National Institute for Hygiene and Epidemiology, told Xinhua on the sidelines of the meeting.

    To early stamp out recent bird flu outbreaks and prevent potential ones in the future, WHO experts called for governments of countries hit by the disease, including Vietnam, China, Indonesia, Thailand and Malaysia to allocate more resources for anti-bird flu activities, and donors to further support disease research as well as human and animal health sector.

    The WHO has recently dispatched a small team of experts to Vietnam, and proposed the country send specimens from local patients, who have been confirmed to have contracted with influenza viruses type A, to its labs in Japan for verification and further analysis.

    "We come here to work with Vietnam´s Ministry of Health and some localities. We will keep on discussing bird flu cases and measures already taken, and then making recommendations," Dr. Futoshi Hasebe, laboratory expert at the CSR Regional Outbreak Response Team under the WHO´s Western Pacific Regional Office, said at the meeting.

    To date, three deaths of a 25-year-old woman from the southern province of Hau Giang and two children from the northern province of Ha Tay have been confirmed to be caused by H5N1 infections by both Vietnam and the WHO.

    "We are now receiving more specimens from local patients. But,15 most doubtful cases have tested negative to H5N1," Mai said.