2017 Volume 70 Issue 7 Pages 438-441
To investigate the effectiveness of commercialized porcine epidemic diarrhea (PED) vaccine, epidemiological data from PED-affected pig farms in Kagoshima Prefecture were analyzed. In a comparison of unvaccinated and properly vaccinated groups, two inoculations of PED vaccine before farrowing reduced the morbidity rate and relative risk of sows and piglets, suggesting the effectiveness of proper vaccination. There were no major differences in the morbidity rate and relative risk of sows between the improperly vaccinated group, such as only one inoculation of PED vaccine before farrowing, and the unvaccinated group. Although the morbidity rate and relative risk of piglets in the improperly vaccinated group were lower than those in the unvaccinated group, it appeared that improper vaccination conferred insufficient protection. The fatality rate and relative risk of piglets did not differ between all the groups, suggesting that the deaths of piglets that developed clinical signs of PED were not prevented by the PED vaccine, although it is possible for the vaccine to suppress the development of PED in piglets. Accordingly, to prevent the loss of piglets, it is essential to decrease the rate of infection of piglets by improving biosecurity at the farms and prevent PED development with proper vaccination.
