Provincial veterinary authorities in Quang Tri province detected highly pathogenic H5N1 avian influenza in a backyard farm of 1700 ducks and 30 chickens, all of which were unvaccinated. They disinfected and isolated the infected and surrounding farms and issued a ban on poultry trading in the area. They also warned other poultry farms to vaccinate the chicks before introducing them to the farm. Raising DOC with no certificate of origin and not vaccinating the birds are the two most common causes of disease outbreaks in Vietnam.