First isolation of bovine herpesvirus 4 (BoHV-4) in a bovine aborted fetus in Argentina

MARIN M; CANTÓN G; LEUNDA MR; LOUGE URIARTE EL; PEREYRA S; GONZÁLEZ ALTAMIRANDA E; SPETTER M; VERNA A; ODEÓN A

Sorrento

Simposio; WAVLD 2017 INTERNATIONAL SYMPOSIUM OF THE WORLD ASSOCIATION OF VETERINARY LABORATORY DIAGNOSTICIANS; 2017

WAVLD

INTRODUCTIONBovine herpesvirus type 4 (BoHV-4) is a gamma-herpesvirus which has been isolated from cattle with diverse clinical manifestations, including metritis, vaginitis and abortions. BoHV-4 was isolated in Argentina from vaginal secretions of aborted cows (Verna et al., 2008). Even though a variety of herpesvirus can cause abortion in cattle the pathogenic role of BoHV-4 remains unclear. The aim of the present work was to describe the occurrence of fetal BoHV-4 infection in a spontaneous bovine abortion.MATERIAL & METHODSA bovine aborted fetus was submitted during 2016 for routine laboratory diagnosis (Campero et al., 2003) to the Veterinary Diagnostic Laboratories at National Institute of Agricultural Technology (INTA), Balcarce, Argentina. Fetal tissues were collected for routine histological examination. Different organs (lung, spleen, liver and kidney) and abomasum content from the fetus were processed for microbiological diagnosis (Campylobacter fetus, Tritrichomonas foetus, Brucella abortus, Leptospira spp.). Neospora caninum antibodies and DNA were evaluated in thoracic fetal fluid (IFAT) and brain (PCR). Homogenates of spleen, lung and brain were processed for viral isolation in MDBK cells. After 4 blind passages of 48-72 h each, cell cultures were tested for BoHV, bovine viral diarrhea virus and bovine adenovirus type 1 and 3 antigens by DFAT. Additionally, DNA extracted from these cultures was analyzed for the presence of BoHV-4 by a nested-PCR assay modified by Verna et al. (2008).RESULTSThe aborted fetus belonged to a beef cattle herd in the ?Humid Pampas? of Argentina, and was the sixth reproductive loss during the calving season. The fetus was a male Aberdeen Angus, with a gestational age of 8 months and without macroscopic lesions. Perivascular hemorrhage in the brainstem, hyperplasia of Peyer's patches and mild mononuclear perivascular cuffing in the spleen were observed. Cytopathic effect compatible with BoHV-4 was consistently observed in all tissue samples assayed for viral isolation, and BoHV-4 DNA was confirmed by nested-PCR. Leptospira DFAT resulted positive in different tissues. Other reproductive pathogens were ruled out.DISCUSSION & CONCLUSIONSBovine abortion with no etiological diagnosis but with pathological findings compatible with infectious diseases is frequent (Campero et al., 2003). In this work, the etiology of this gestational loss is unclear since the histopathological lesions were mild. Although positive structures compatible with Leptospira spp. were detected, the absence of characteristic lesions makes it unlikely that it had a primary role in abortion. BoHV-4 DNA was detected after viral isolation and previous studies suggested a close association between BoHV-4 and bovine abortions (Deim et al., 2007; Delooz et al., 2016). This work describes the first BoHV-4 isolation from a bovine aborted fetus in Argentina. Although the presence of BoHV-4 does not prove an etiological role in this abortion, the results confirmed the ability of BoHV-4 to infect the bovine fetus. The present study indicates that BoHV-4 could have played an active role in the abortions observed in this beef herd.