AUTHOR=Pedersen Kasper , Blirup-Plum Sophie Amalie , Kristensen Charlotte Sonne , Kvisgaard Lise Kirstine , Skade Lotte , Jensen Henrik Elvang , Larsen Lars Erik 

TITLE=Virological and Histopathological Findings in Boars Naturally Infected With Porcine Reproductive and Respiratory Syndrome Virus Type 1

JOURNAL=Frontiers in Microbiology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.874498

DOI=10.3389/fmicb.2022.874498

ISSN=1664-302X

ABSTRACT=Major geographical transmission of PRRSV occurs via semen when a boar stud is infected. This happened in Denmark in 2019, providing an opportunity to compare previous experimental PRRSV boar studies with natural infection of boars. The aim of this study was to investigate the association between the presence of PRRSV RNA in serum, semen, testicles and epididymis of boars naturally infected with PRRSV and to describe the histological lesions in the testes and epididymis combined with direct visualization of PRRSV-infected cells by immunohistochemical staining (IHC). The exact time of infection of each boar was not determined but based on serology the boars was divided into two groups: acute and late infections. All boars included were sampled the same day. Thirty-five (35) boars and ten healthy boars from another PRRSV-negative boar stud were included in the study as histological controls. PRRSV RNA was found most often in serum (51%) and least frequently in semen (22%) and was more often detected in the reproductive tract in the acute phase of infection (p < 0.0001; RR: 2.58). Mononuclear cells and multinuclear giant cells were present in the adluminal compartment of the testis and epididymis in PRRSV-infected boars, but not in control boars (p < 0.05), which supports the hypothesis that macrophages are involved in the venereal spread of the virus.