Detection of Infectious Bovine Rhinotracheitis in Natural Cases of Bovine Abortion by PCR and Histopathology Assays

Abstract

Bovine herpesvirus 1 (BHV-1), the causative agent of infectious bovine rhinotracheitis (IBR), is considered to be the most common viral pathogen found in bovine. Bovine Herpesvirus 1(BHV-1) belongs to the genus of Varicellovirus and the family of Herpesviridae which contains three main gB, gC and gD genes. The objective of this study was to determine the relation between type of macroscopic lesions and bovine herpesvirus-1(BHV-1) infection; hence the aborted fetus specimens were initially prepared for PCR test. In this study, 23 of fetus samples, which were transferred to Veterinary Laboratories during 2009-2012, were assessed for BHV-1 with PCR in lung and spleen tissues and all of positive samples undergone histopathological study. The results indicated myocarditis and necrosis of cardiac tissue in 8 cases (42.1%), and 6 cases encompassed interstitial lymphocytic pneumonia (28.57%), whereas 5 cases revealed bronchopneumonia (23.8%) and in 8 cases (38.09%) severe interstitial edema was observed. In addition, the lesions may be associated with BHV-1, so that in brain tissue 9 cases (36 %) possessed encephalitis and necrosis, 8 cases (38.09%) indicated interstitial nephritis, 2 cases (9.52%) developed acute tubular necrosis, 2 cases (9.52%) revealed vacuolar degeneration inrenal tubular epithelium, 1 case had (4.76%) renal hemorrhage and in 3 cases (14.28%) renal autolysis was observable. In liver, 10 cases (47.61%) were affected to lymphocytic hepatitis, 5 cases (23.8%) possessed necrotic hepatitis, 6 cases (28.57%) of multifocal coagulative necrosis without inflammatory reaction and 3 cases (14.28%) with lymphocytic portal hepatitis were observed. In this assessment, 10 specimens (52.17%) of spleen tissues revealed necrosis and lymphatic tissues emptying and in 10 cases (100%) severe enteritis, which may be associated with IBR, were recorded. This study suggests based on lesions in several organs induced by IBR virus and real time PCR confirmation there is direct correlation between virus and lesions, and in order to obtain more reliable results of IBR infection the histopathological examination may be efficient.