Molecular Characterization of Bovine Rotaviruses and Coronaviruses in Diarrheic Calves in Egypt (2014-2019)

Bovine Rotaviruses group A (BRVA) and Bovine Coronaviruses (BCoV) are the most prevalent viral agent worldwide in diarrheic calves aged less than 6 weeks, causing economic losses due to retarded growth, increased susceptibility to other infections, treatment cost, and calf mortalities. This study aimed to detect and molecularly characterize BRVA and BCoV from diarrhetic calves. A total of 82 fecal samples were collected from calves aged less than one month from three Egyptian governorates (Alexandria, Ismailia, and Sharqia). All fecal samples were tested for BRVA and BCoV by using probe based quantitative reverse-transcription polymerase chain reaction (qRT-PCR). Consequently, positive samples contain relatively high viral genomic load were examined by RT-PCR for amplification of viral protein 7 (VP7) and viral protein 4 (VP4) genes (G- and P- typing) for BRV and full length S1 gene for BCoV. Out of 82 of tested samples, 14 (17.1%) and 22 (26.8%) were positive by qRT-PCR for BRV and BCoV, respectively. Only three and five samples had relatively high genomic load for BRV and BCoV, respectively for further testing by RT-PCR. BRV G-type was found in two samples and P-type was detected in one sample. The sequence analysis and phylogenetic tree typed these positive samples as P11 and G10. The sequences and phylogenetic analysis of BCoV positive strains (n=5) showed closely related viruses to each other and similar to previously characterized strains in Egypt since 2014. Further studies are required to antigenically characterize the circulating BRV and BCoV in Egypt.