MOLECULAR ANALYSIS OF OUTER CAPSID PROTEIN (VP7) GENE OF ROTAVIRUS RECENTLY ISOLATED FROM NEWLY BORN CALVES IN EGYPT

M.I., ABD EL HAMID,; SALEH, AMANI ALI; EL-SEBAY, NADINE A.; FARAHAT, LUBNA F.; EL-NAGAR, EMAN M.S.

doi:10.21608/avmj.2025.320432.1398

MOLECULAR ANALYSIS OF OUTER CAPSID PROTEIN (VP7) GENE OF ROTAVIRUS RECENTLY ISOLATED FROM NEWLY BORN CALVES IN EGYPT

Document Type : Research article

Authors

¹ Genetic Engineering Research Department, Veterinary Serum and Vaccine Research Institute (VSVRI), Agricultural Research Center (ARC). Cairo, 11381, Egypt.

² 1 Prof. of Virology, Veterinary Serum and Vaccine Research Institute (VSVRI), Agricultural Research Center (ARC). Cairo, 11381, Egypt.

³ Department of Quality Management, Veterinary Serum and Vaccine Research Institute (VSVRI), Agricultural Research Center (ARC). Cairo, 11381, Egypt

10.21608/avmj.2025.320432.1398

Abstract

Rotavirus is a contagious viral disease causing acute watery diarrhea. It has a potential zoonotic and economic importance in calves under one month of age, widely. So during early January 2024, a total of 46 diarrheic samples were collected from dairy calves (2-4 weeks old) in El-Sharqia, Giza, New Valley (El-Kharga Oasis), and El-Beheira governorate. Tissue culturing, serological (ELISA), and molecular identification based on sequencing analysis of the VP7 gene of Rotavirus A (RVA) were done. Among the 46 diarrheic samples, only 24 samples (52%) were RVA-positive by ELISA and negative for both coronavirus and E. coli. RVA was successfully isolated on MDBK and VERO cells, as an obvious cytopathic effect was produced at the first and second passages of both cell lines, respectively. Haemagglutination (HA) activity of positive samples ranged from 1:4 to 1:16. Molecular and sequencing analysis of the VP7 gene revealed that the four sequenced rotavirus isolates belong to Bovine Rota Virus A (BoRVA), Genotype 6, with 100% identity to each other and 98.26% similarity with the local Egyptian isolates, clustered in the G6 lineage with the Argentina, USA (Scour Guard vaccine), Ireland, and Indian BoRVA strains with identity matrices of 95.42%, 93.4%, 93.31%, and 90.49%, respectively. Conclusively, the Egyptian BoRVA G6 strains are widely circulating in Upper and Lower Egypt among dairy calves. It is recommended to evaluate those strains together with G8 and G10 as vaccine candidates in the locally prepared vaccine to confer full protection against BoRVA circulating in Egypt.

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