Epidemiological parameters and preventive measures of PRRS in 2010-2011 in three districts of Tien Giang province were investigated and analyzed from 2,267 surveyed questionnaires for disease occurrence, in 348 pig-raising households and 37,907 pigs vaccinated against PRRSV (serotype JXA 1-R) in 354 households. Pig raising household rate having PRRS infected pigs reached at peak in the 4th week since starting disease outbreak. Incidence of PRRS occurring in the highdensity pig raising district (Cho Gao) was faster than in My Tho city and Chau Thanh district. Households having PRRS infected pigs were due to not implementing or incompletely implementing bio-security measures
of which 28.96 percent of households did not apply primarily bio-security measures. In the first 6 months of 2012, live vaccine (serotype JXA 1-R ) was used to inject pigs inside the outbreak area. After injection only 0.5 percent of pig numbers were infected with PRRS in the households who did not have disease pigs during the outbreaks, and 14.9 percent of pig numbers were infected with PRRS in the households having disease pigs during the outbreaks.