Intermittent elimination of Porcine Parvovirus 4 (PPV4) in naturally infected swine semen: first report

Abstract

Porcine parvovirus 4 (PPV4) has been reported in several countries and the high rate of concurrent PCV2 infection with PPV4 may trigger the "porcine circovirus disease" (PCVD). This has awakened the interest in how PPV4 virus behaves. The aim of this study was to show that, like other swine viruses, the elimination of PPV4 in semen is intermittent. The study was conducted in the Unidade de Pesquisa e Desenvolvimento de Itapeva da Agência Paulista de Tecnologia dos Agronegócios Regional (Apta Regional). Over a period of six months, four boars were monitored and the semen was collected every 10 days, totalizing 74 semen samples. Through PCR testing, PPV4 was detected in 32/74 (43.2%) semen samples. Three sequences of 284 nt, showed identity varying from 98.2% to 100%, confirming the detection of the virus in all boars. Semen volume and sperm motility did not indicate significant difference between PPV4 positive or negative semen samples (p > 0.05). There was no significant difference between the monthly distributions of positive and negative samples. This is the first study showing intermittent shedding of PPV4 in naturally infected boars. Absence of typical clinical signs and/or influence in semen quantity was also observed.