HANOI, July 8 (Xinhua) -- The Porcine Reproductive and Respiratory Syndrome (PRRS), known as "blue ear" disease, has recently stricken Vietnam's northern Quang Ninh province, raising the total number of affected localities in the country to six, according to a local veterinary agency on Tuesday.

    The disease killed 67 pigs and sickened 416 others raised by 15households in Yen Hung district, the Department of Animal Health under the Ministry of Agriculture and Rural Development said, adding that the PRRS is currently hitting six Vietnamese provinces, including the two northern provinces of Lao Cai and Quang Ninh, and the four southern provinces of Vinh Long, Bac Lieu, Ba Ria Vung Tau and Soc Trang.

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