HANOI, June 11 (Xinhua) -- "Blue ear" disease, or Porcine Reproductive and Respiratory Syndrome (PRRS), has hit Vietnam's southern Bac Lieu province since early this month, leading to the forced culling of 170 pigs, according to local newspaper Pioneer on Wednesday.

    The disease, breaking out in Vinh Loi district on June 3, has affected the pigs raised by 18 households in the district, the newspaper quoted local veterinary bureaus as reporting.

    Now, PRRS is hitting seven Vietnamese provinces, including ThaiBinh and Thai Nguyen in the northern region, Thua Thien Hue and Lam Dong in the central region, and Vinh Long, Binh Phuoc and Bac Lieu in the southern one, according to Vietnam's Department of Animal Health under the Ministry of Agriculture and Rural Development.

    PRRS was first recognized in the United States in the mid-1980sand is now present in most pig-producing countries. The symptoms include reproductive failure, pneumonia and increased susceptibility to secondary bacterial infection.