Detection of atypical porcine pestivirus in semen from commercial boar studs in the United States

Abstract

Atypical porcine pestivirus (APPV) has recently been identified as a cause of congenital tremor (CT) in pigs and has been detected in semen and preputial swabs from boars that were known to be clinically affected with CT. Accordingly, the objectives of this study were to 1) detect the presence of APPV in semen, preputial fluids and preputial swabs from adult boars by quantitative reverse transcription PCR (qRT-PCR) and 2) genetically characterize a subset of positive samples to better understand the ecology of APPV in commercial boar studs and the potential risk of transmission of APPV via semen. A total of 597 samples of semen, preputial fluid and preputial swabs each representing a different boar were obtained from four commercial boar studs located in three different states in the United States. Viral RNA was detected by qRT-PCR in 90 samples (15.08%; 90/597), with the greatest per cent positive from preputial swabs (23.81%; 5/21) followed by preputial fluid (22.81%; 26/114) and semen (12.91%; 59/457). The mean cycle quantification (Cq) between sample types was similar while eleven semen samples had Cq values lower than 27.0 corresponding to approximately 2 × 10 copies/ml. Based on phylogenetic analysis of the Npro gene, different viral strains can be on the same farm at the same and different times. This is the first report of detection of APPV in semen from commercial boar studs. Studies investigating the role of semen in the transmission of APPV and production of CT are needed.

Detection of atypical porcine pestivirus in Brazil in the central nervous system of suckling piglets with congenital tremor

“…Recently, APPV was detected in semen from commercial boar studs in the United States exposing a potential mode of transmission and clinical expression of APPV (Gatto et al., ). Anecdotally, newly populated breeding herds are at increased risk for CT outbreaks, and this may be due to naive gilts being exposed to APPV through semen.…”

“…Due to the fragmented nature of formalin-fixed RNA, three primer Table 2. Results from clinically non-affected piglets are presented in Supplementary Table 1 Recently, APPV was detected in semen from commercial boar studs in the United States exposing a potential mode of transmission and clinical expression of APPV (Gatto et al, 2017). Anecdotally, newly populated breeding herds are at increased risk for CT outbreaks, and this may be due to naive gilts being exposed to APPV through semen.…”

Das neu entdeckte „atypische porzine Pestivirus“ (APPV): ein alter Akteur im „Zitterferkelkrankheit“-Komplex?

“…Auch für APPV konnte ein positiver Nachweis für Sperma und Präputialsekret bei klinisch unauffälligen Jungebern erbracht werden, die als Zitterferkel geboren worden waren (14,46). Eine aktuelle Studie aus den USA berichtet über eine Genomprävalenz von etwa 15 % (90 von 597 getesteten Proben) in Spermaproben aus unterschiedlichen Bundesstaaten (24). Dabei ist jedoch unklar, ob es sich um klinisch unauffällige transient infizierte Eber handelte oder ob der Erreger im Genitaltrakt persistiert (24).…”

Evolution and genetic diversity of atypical porcine pestivirus (APPV) from piglets with congenital tremor in Guangxi province, Southern China

“…APPV infected piglets are characterized by generalized body shaking with variable degrees of hypomyelination in brain and spinal cord. APPV has been discovered in both domestic pigs and wild boar populations [17,26,27], suggesting APPV has wide range of hosts. High APPV loads were detected by qRT-PCR in semen, serum and different tissue samples of clinically healthy domestic adult pigs and commercial boar studs [7,27], indicating there existed persistent infection and this virus could possibly be transmitted by artificial insemination.…”

“…APPV has been discovered in both domestic pigs and wild boar populations [17,26,27], suggesting APPV has wide range of hosts. High APPV loads were detected by qRT-PCR in semen, serum and different tissue samples of clinically healthy domestic adult pigs and commercial boar studs [7,27], indicating there existed persistent infection and this virus could possibly be transmitted by artificial insemination. Besides horizontal transmission through oronasal pathway, APPV could also be vertically transmitted by transplacental infection [4,5].…”