||Bovine herpesvirus 1 (BoHV-1); a significant viral pathogen of cattle, is an alpha-herpesvirinae sub-family member that causes significant economic losses to the cattle industry. Infection of cattle with BoHV-1 can lead to conjunctivitis, genital disorders, abortions and bovine respiratory disease complex (BRDC) or shipping fever.
The present study aimed for studying the seroprevalence of BoHV-1 neutralizing antibodies in serum samples of different obtainable governorates as well as trails for isolation and identification of BoHV-1 through achieving the following:-
1. Studying the prevalence of BoHV-1 neutralizing antibodies in sera from apparently healthy cattle and buffaloes from different governorates in Egypt with VNT revealed that: 26.8% and 25.2% were found to be positive for BoHV-1 antibodies; while in ELISA; 37.3% and 33.9% where found to be positive from the total serum samples obtained from cattle (153) and buffalo (103) respectively.
From own findings; BoHV-1 was present and circulated among cattle and buffalo herds in Egypt. In addition; the comparative detection suggested that ELISA was more superior and sensitive comparing to VNT.
2. An attempt for raising of hyper immune serum against BoHV-1in rabbits using the CFA/IFA immunization regimen with detection and assaying of the polyclonal antibodies titer with SNT and ELISA was succeed as well as giving satisfactory results with indirect fluorescent antibody technique.
3. Trials for Isolation of BoHV-1 from the nasal swabs obtained from naturally infected cattle and buffaloes on MDBK cell line were adopted and revealed that 8.6% and 4.6% from the total nasal swabs from cattle and buffalo respectively, were positive for presence of BoHV-1through induction of CPE on MDBK cells in the form of (cell rounding, cells aggregation in grape-like clusters with cell detachment and death).
4. Serological identification of suspected BoHV-1 isolates in inoculated cell culture using IFAT showed positive results with 6 out of 8 (out of 93 cattle samples) induced previously cytopathic effect on MDBK cell culture, While similar to VI assay ; the IFAT; equally; identified all of the 3 out of 65 total buffalo samples.
5. Molecular identification of suspected BoHV-1 isolates using the polymerase chain reaction (PCR) assay, utilizing specific primers derived from the tk gene coding sequence of bovine herpesvirus-1genome was done, where; PCR was superior to immunodetection using IFAT after VI procedure in cell culture. Besides, it was the most discriminative assay that detected BoHV-1 viral DNA extracted directly from (100%) of buffalo and (88.9) of cattle nasal swabs.
Findings of this study emphasized the BoHV-1 tk based PCR as a sensitive, discriminative and rapid tool for detection of BoHV-1 infections, without confusion with other ruminant herpesviruses. Moreover; our results obtained herein coincide with recent reports regarding the presence and circulation of BoHV-1among cattle and buffalo herds in Egypt as well as molecular importance of the tk gene based PCR assays for pathogenesis and epidemiological studies of BoHV-1 infections.