Officials in Vietnam have admitted that an isolated outbreak of bird flu has occurred in the south, more than a month after the country said it was free of the disease.

Veterinary official Bui Quang Anh said a new case had been detected in Dong Thap province, reported the Associated Press.

“There was one outbreak on a small scale in one family. As soon as it was discovered, the outbreak was immediately contained. The chickens were handled carefully in order to prevent the spread of infection,” he told a local paper. 

Officials destroyed all the chickens on the farm, and set up a quarantine that included farms in the surrounding area, after tests confirmed the presence of the H5N1 virus, the same strain of bird flu that spread across many parts of Asia earlier in the year. One of the worst-hit countries was Vietnam, where the disease led to the cull of around 43 million poultry. The virus also spread to humans, killing 16 people in Vietnam.