Nguyen Duc Hai, head of the province administration, said since the 21-day period was the criterion for declaring an area disease-free, normal activities had resumed Friday.

However, animal health experts warn that the virus that causes Porcine Reproductive and Respiratory Syndrome (PRRS), as the disease is known in medical parlance, can exist in infected animals for up to two months.

Quang Nam recorded its first outbreak in June after which the disease spread to 11 districts and communes, infected over 32,000 pigs, and caused the culling of about 9,000 animals.

Seven provinces were hit in Vietnam but only three remain on the infected list – Quang Ngai, Binh Dinh, and Ba Ria-Vung Tau – according to the Animal Health Department.

The PRRS virus, first recognized in the US in the mid-1980s, reduces immunity in pigs and leads to secondary infections of bacterial diseases like Streptococcus Suis and salmonella, and is also associated with other viruses.

Further Reading

- Find out more information on PRRS by clicking here.