Jun 30, 2004 (CIDRAP News) – Three months after Vietnam declared itself free of avian influenza, the disease has struck there again, causing the loss of at least 4,500 chickens in a southern province, according to news services.A Reuters report today said chickens on three farms in the Mekong Delta province of Bac Lieu died or were destroyed after testing positive for an H5 avian flu virus.Reports did not specify the N (neuraminidase) number for the virus, leaving unclear whether it was identical to the H5N1 strain blamed for the widespread outbreaks in Vietnam and seven other Asian countries earlier this year.Local animal health officials said all tested birds from the affected farms carried the H5 virus, according to the Reuters story and a report by Xinhua, China’s state news agency.Anton Rychener, Vietnam representative for the United Nations Food and Agriculture Organization, said the new outbreak is not surprising and “is nothing to panic about,” according to Reuters.Last week, a Vietnamese agricultural official said 10,000 poultry from throughout Vietnam had been tested for avian flu, and many of the samples were positive for an H5 virus. The comments by Nguyen Van Thong were published in a Jun 27 Agence France-Presse report. He said the precise strain of the virus could not be identified.Vietnamese officials declared the country free of avian flu on Mar 30. A small outbreak of H5N1 avian flu was reported in the southern province of Dong Thap in early May.In the outbreaks earlier in the year, the disease jumped to humans, causing 23 cases with 16 deaths in Vietnam, according to reports from the Vietnamese government. However, the World Health Organization (WHO) has confirmed only 22 cases with 15 deaths. The disease killed or prompted the destruction of 43 million poultry in Vietnam.