what we know about persistent infection with respect to the epidemiology of PRRS virus

摘要

Infection with PRRS virus produces clinically normal, but chronically infected, carrier animals. Although this is old information, because of its impact on the perpetuation of the disease in swine populations it still remains the single most important fact in the epidemiology of PRRS virus. Zimmerman et al. (1992) first reported transmission between sows infected 99 days earlier and commingled susceptible animals. Albina et al. (1994) demonstrated transmission of PRRS virus by pigs infected 15 weeks earlier. Christopher-Hennings et al. (1995) reported detection of viral RNA in 'the semen of experimentally infected boars through day 92 post exposure and isolation of PRRS virus from the bulbourethral gland of a boar euthanized 101 days after inoculation. Wills et al. (1997) isolated virus from oropharyngeal samples for Up to 157 days after experimental inoculation. Benfield et al. (1997) reported detection of viral RNA for up to 210 days post farrowing in pigs exposed to virus in utero.