Serological and Molecular Identification of Infectious Bovine Rhinotrachetitis Virus Isolation and Adaptation in Embryonated Chicken Eggs

Abstract

Infectious bovine rhinotracheitis virus (IBRV) is a major pathogen in livestock animals and had led to significant economic losses to the industrial production worldwide. However, IBR symptoms are not life-threatening. The present study was achieved to make seroprevalence and isolation of bovine herpes virus type (BHV-1) from nasal and ocular swabs samples of suspected cows and buffaloes, identification by serological and polymerase chain reaction (PCR). Total of 380 blood samples were collected from suspected 287 cattle and 93 buffaloes in different districts at Beni-suef and El-Fayoum governorates in winter 2017. Nasal and ocular discharge swabs were collected from cattle and buffaloes with clinical respiratory signs (Nasal discharge, cough, lachrymal discharge with or without mild diarrhea and higher body temperature). A total of 106 (27.89%) samples were positive by indirect ELISA and the positivity of 80 (27.87%) samples from cattle and 26 (27.96%) samples from buffaloes located at different centers at Beni-Suif and El-Fayoum governorates. Virus was isolated from nasal and ocular discharges swabs samples and it was adapted in chorioallantoic membrane (CAM) of 11-day-old embryonated chickens eggs and in MDBK cells. Virus-infected CAM showed congestion, edematous vacuole, thickening small foci ranged from 2 to 3 mm in diameter, scattered on CAM membrane and MDBK cell line inoculated blind serial passages at 3rd passage showed characteristic of cytopathic effect (CPE). Identification of virus isolated on CAM and infected cell culture fluid gave precipitation against positive specific anti-BHV-1 immune serum by AGPT and clear blue zone by Dot ELISA, absent of pock lesion in pock reduction test (PRT), and confirmed by PCR with product size of 175 bp. Finally BHV-1 virus was isolated from nasal and ocular discharges of cattle and buffaloes but the further extensive study still need for clear final classification by phylogenic analysis.