HANOI, June 7 (Xinhua) -- Rampant reproduction of waterfowls, mainly ducks which have not been vaccinated against bird flu viruses, is the main cause of the disease's new outbreaks in Vietnam, local newspaper People reported Thursday.

    Up to 99 percent of poultry that have either been infected with or died of bird flu since early May are waterfowls, mainly unvaccinated ducks aged below two months. Since the country's Ministry of Agriculture and Rural Development in late February removed a two-year national ban on hatching waterfowl eggs and restocking waterfowl flocks, an increasing number of ducks have been produced in many localities.

    Worryingly, it is very difficult to manage the reproduction and the movement of waterfowls, and to vaccinate them. Having no suitable bird flu vaccines to vaccinate one-day-old ducks, Vietnam can not vaccinate them right at the egg incubators, the newspaper said, noting that it only can vaccinate ducks aged over 14 days.

    Vietnam finds it difficult to vaccinate all of waterfowls, since most of them are raised freely at household scale, not in concentrated farms, and the country's veterinary forces are weak both in terms of quantity and quality.

    Vietnam, spending over 246 billion Vietnamese dong (VND) (15.4 million U.S. dollars) on vaccinating poultry nationwide between 2005 and 2006, has decided to set aside nearly 278 billion VND (17.4 million dollars) on the vaccination in the 2007-2008 period, said the newspaper.

    Bird flu, starting to strike Vietnam in December 2003, has, since early May, hit poultry in a total of 15 Vietnamese cities and provinces nationwide.