Preliminary molecular study for DIVA trial of antigenically characterized circulating bovine herpesvirus subtype 1.1 in Egypt.

Basel A Abukhadra, Sahar Abd El Rahman, Mohamed A Soltan, Giuma E Elhafi, Samah M Mosad

Virology 2024 May

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Using marker vaccines to control bovine alphaherpesvirus-1 (BoHV-1) is a novel strategy for differentiation between infected and vaccinated animals (DIVA). In this study, multiplex real-time PCR targeting gD and gE genes was applied for BoHV-1 screening on 60 clinical samples from cattle with a history of vaccination, in some cases by US2-deleted marker vaccines, that were suffering from severe respiratory symptoms. Conventional PCR targeting the gC and US2 flanking region was done for molecular characterization and identification of the US2-deleted vaccine strain. Six samples were positive for BoHV-1 by both RT-PCR and conventional PCR. Surprisingly, a conventional PCR DIVA trial based on the US2 gene revealed that only one sample that exhibited the US2 gene was a wild virus, while others that did not exhibit the US2 gene were vaccine viruses. Phylogenetic characterization classifies the samples as BoHV-1.1. This finding reveals the circulation of vaccine virus in field-diseased animals, which threatens the eradication program. Copyright © 2024 Elsevier Inc. All rights reserved.

Citation

Basel A Abukhadra, Sahar Abd El Rahman, Mohamed A Soltan, Giuma E Elhafi, Samah M Mosad. Preliminary molecular study for DIVA trial of antigenically characterized circulating bovine herpesvirus subtype 1.1 in Egypt. Virology. 2024 May;593:110012