Molecular and Virological characterization of local isolate of Equine Herpes Virus -4 among aborted mares from Egypt 2022

Document Type : Original Article


Department of Virology, Faculty of Veterinary Medicine, Benha University


This work aimed for detection of EHV-4 in samples from suspected mares and aborted feti from Cairo and Giza, Egypt, 2022 followed by studying its phylogenetic, serological and culture characters on primary RK cells and VERO cell line. Samples were collected, prepared as virus suspension, undergone molecular identification by cPCR using primers specific for gB of EHV-4. Results revealed amplicon size of the amplified DNA product at 508 bp. Sequencing of the partially amplified gB gene and phylogenetic analysis of positive samples showed 100%, 99.8% and 99.6% nucleotide similarity with other EHV-4 strains reported in the GenBank. Virus isolation showed appearance of CPE after 5 dpi at 5th passage and 3dpi at 3rd passage for RK and VERO cells respectively. CPE of EHV-4 isolate characterized by cell rounding, aggregation, clustering and cell lysis. Titration was done on both primary RK cell culture and VERO cell line for all passages, the virus titer increased gradually to reach the highest level in the 5th, 6th passages in RK cells and 3rd, 4th passages in VERO cells. The growth kinetics of EHV-4 isolate using 0.5 ml virus dose with dilution 10-1 cell/ml revealed that the MOI of EHV-4 isolates at 4 and 5 dpi and the optimum titer was log10 5.5 TCID50/ml. Serological identification of the virus isolate showed positive results with IFAT and VNT using specific reference antisera. Finally, the evaluation approved that our EHV-4 strain is more genetically related to the same old strains in Egypt causing the disease.


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