In this study, the prevalence of porcine reproductive and respiratory syndrome virus (PRRSV) infection on swine farms in Japan was investigated. Out of 92 farrow-to-finish swine farms targeted in this study, 82.6% (76/92) were positive for PRRSV. The post-weaning mortality of the PRRSV-negative group was significantly lower than that of the PRRSV-positive group (negative: 3.9%, positive: 6.1%: P < 0.01). The average daily weight gain of the PRRSV-negative group was significantly higher than that of the PRRSV-positive group (negative: 638.8 g, positive: 585.1 g: P < 0.01). The Kanto region was significantly associated (P < 0.01) with PRRSV-positive status (odds ratio (OR) = 41.8, 95% confidence interval (CI) = 4.80-363.0). With respect to farm location, the presence of other pig farms within a 3-km radius were significantly associated (P < 0.05) with PRRSV-positive status (OR = 4.09, 95% CI = 1.07-15.70). Our findings suggest that PRRSV significantly worsens farm productivity. Regional collaboration is an important strategy required to control or eliminate PRRSV.
(Viral Disease and Epidemiology Research Division)
Ishizeki S. et al (2014) Anim. Sci. J. 85:171-177