Molecular Typing of Rotaviruses in Diarrheic Neonatal Calves

Abstract

Rotavirus ribonucleic acid was extracted from 16 fecal samples of the serologically positive diarrheic calves using Latex agglutination test (LAT) and Immunochrmatographic assay (ICA). The extracted RNA was submitted to Reverse transcriptase polymerase chain reaction (RT-PCR) to detect VP7 and VP4 genes and the positive samples were 100% (16/16) and 81.25% (13/16), respectively. The amplified products were subjected to G and P-genotyping by semi-nested multiplex PCR using of G6, G8 and G10 genotyping and P1, P5 and P11 genotyping primers, respectively. G6 was detected in 10 (62.50%) of 16 samples and G10 was diagnosed in 5 (31.25%) of 16 samples and one (6.25%) sample did not react with any G primer used. P5 was detected in 9 (56.25%) of 16 samples, P11 was diagnosed in 3 (18.75%) of 16 samples, mixed infection with P5+P11 was observed in 1 (6.25%) of 16 samples and 3 (18.75%) samples did not react with any P primer used. G and P genotypes combination revealed that G6P5 was in 50% (8/16), G10P11 in 12.50% (2/16), G10P5 in 6.25% (1/16), G6P11 in 6.25% (1/16), G10 (P5+P11) in 6.25% (1/16), G6P? in 6.25% (1/16), G10P? in 6.25% (1/16), and G?P? in 6.25% (1/16). These results suggest that the detected genotypes can used as dominant strains for the formulation of an appropriate vaccine against BRV in Assiut Governorate. In conclusion, RT-PCR and Semi-nested multiplex PCR can used as rapid and confirmatory test for detection of nucleic acid and genotypes of Rotavirus, G and P genotypes combination in the present study revealed that G6P5, G6P11, G10P5 and G10P11 were circulating genotypes in bovine population in Assiut governorate. G6P5 strain was the most common of all strain diagnosed in other fecal samples. The presence of various combinations of G and P genotypes among field isolates of BRV suggests that genetic reassortment frequently occurred between viral strains with genes encoding different G and P genotypes. Finally, presence of different genotypes of Rotaviruses emphasizes their simultaneous monitoring in animals for the development and optimization of Rotavirus vaccines.