J Vet Sci.  2002 Jun;3(2):87-95.

Localization of Porcine Reproductive and Respiratory Syndrome Virus Infection in Boars by In Situ Riboprobe Hybridization

• Shin JH
• Molitor TW

Abstract

The capability of porcine reproductive and respiratory syndrome virus (PRRSV) to be shed in semen for extended periods of time has been suggested to be a principal factor for viral transmission via insemination. In attempts to gain insights into the mechanism of PRRSV persistence in boars, tissue distribution and sites of viral infection were investigated by in situ hybridization (ISH) using digoxigenin-labeled RNA probe and the ISH results were compared with those of reverse transcription-nested polymerase chain reaction (RT-nested PCR). Animals were intranasally inoculated with 104 median tissue culture infectious dose of PRRSV VR-2332 and tissues collected at different times were examined. At day 7 postinfection, limited number of hybridization positive signals was observed in cells within or between seminiferous tubules in the testis sections while relatively abundant hybridization positive signals were observed in the brain stem and tracheobronchial lymph node. At later days of infection, hybridization positive signals were observed in cells within seminiferous tubules with much reduced frequency. Lack of agreement with the RT-nested PCR assay results in testis tissues obtained at days 14, 28, and 59 postinfection suggested that PRRSV infection in the testis may be extremely restricted, and may not necessarily constitute a major viral source in semen during extended periods of seminal shedding.

MeSH Terms

Animals
Brain Stem/virology
Endopeptidase K/metabolism
*In Situ Hybridization
Lymph Nodes/virology
Male
Microwaves
Porcine Reproductive and Respiratory Syndrome/transmission/*virology
Porcine respiratory and reproductive syndrome virus/*genetics/*isolation & purification
RNA Probes
Reverse Transcriptase Polymerase Chain Reaction
Semen/virology
Seminiferous Tubules/virology
Sensitivity and Specificity
Sexually Transmitted Diseases, Viral/transmission/veterinary/virology
Swine/*virology
Testis/virology