A sertés reprodukciós zavarokkal és légzőszervi tünetekkel járó szindró mája (PRRS) és a betegséget okozó vírus biológiája Irodalmi összefoglaló

Abstract

SUMMARY In this paper the authors briefly summarize the global and Hungarian history of the Porcine reproductive and respiratory syndrome (PRRS) disease. They also review the latest results targeting host virus interactions and explain the causes of the broad spectrum of the pathology and pathogenesis of the disease. The PRRSV emerged almost simultaneously in the USA and Europe at the end of the 1980s. Since then, the disease remained one of the biggest health threats to the global swine industry. The virus was first detected in 1995 in Hungary, but it has caused more significant economic losses only since 2002. As a consequence of its economic impact, the virus has been intensively studied over the last two decades. The PRRSV belongs to the Arteriviridae family, it contains a single stranded, positive-sense RNA genome with at least ten open reading frames (ORFs). The PRRSV can be divided into two major genotypes: type 1 (European) and type 2 (North American). Despite the distinct genetic and antigenic differ ences they cause very similar symptoms. In neonatal pigs the PRRSV infection causes respiratory disease, while in sows the most frequent clinical signs are reproductive failures. The primary cell targets of the virus are the alveolar mac rophages in the respiratory tract. The main reason of the abortion and stillbirth is the damage of the maternal-foetal interface and infection of the foetus. One of the major differences between the two genotypes is the cell tropism. Though CD163 seems to be a main receptor for both genotypes, sialoadhesin receptor is necessary only for the majority of type 1 viruses but the type 2 PRRSV and a few type 1 strains can infect macrophages without sialoadhesin receptor. The PRRSV is very often associated with other viral and bacterial pathogens (Pas teurella multicida, Mycoplasma hyopneumoniae and PCV-2) and to the porcine respiratory disease complex (PRDC). Unfortunately, the genetic background of the virulence and the pathogenicity is not completely clear yet. The available vaccines against PRRSV do not give full protection, and the high genetic diver gence of the virus and its immune-evasive ability hinder the development of effective vaccines.