Infectious agents involved in reproduction failure in swine

Abstract

Problems in the reproduction of pigs may be the result of interaction of various factors, both infectious and non-infectious. Among the infectious agents, the greatest economic losses are caused by viral infection of pregnant gilts and sows. In the present study the most important pathogens causing reproductive disorders in pigs, including parvovirus (PPV), porcine reproductive and respiratory syndrome (PRRSV), swine influenza virus (SIV), porcine circovirus type 2 (PCV2), enteroviruses, encephalitis virus (EMCV), Aujeszky's disease virus (ADV), classical swine fever virus (CSFV), Leptospira spp., Brucella suis and Erysipelotrix rhusiopathiae are characterized. So far, three possible ways of natural infection of the embryo or fetus are identified: via placenta, through the cervical canal, and by infection of the egg cell. The consequences of infection of pregnant females depend on the species of the virus, the gestation period, wherein there is an infection and immune status of pregnant females. The most common changes included: embryo death, resorption of embryos, mummification of fetuses, malformations, abortions, birth of dead or very weak piglets. Because of the importance of the reproduction sector for the competitive production of pigs, the monitoring of the health status of breeding stock, including compliance with all biosecurity rules and vaccination schedules, should be strictly respected by veterinarians taking care of pig breeding herds