| Abstract |
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.
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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. |
