Nsp4 gene based genetic diversity among diarrheic bovine and human group A rotaviruses
Abstract
Rotaviruses are the major cause of severe gastroenteritis and mortality in young children and animals. The rotavirus genome is composed of eleven segments of double-stranded RNA. Due to segmented nature of the RNA genome and wide host range, vast genetic and antigenic diversity exists amongst different isolates of rotavirus. Genetic diversity based on NSP4 gene sequence analysis of local bovine and human group A rotaviruses may help in improvement of further control strategies. Keeping these perspectives in the view, the present study was undertaken to know the genetic diversity among bovine & human group A rotaviruses by phylogenetic analysis based on NSP4 gene sequences. A total of 150 faecal samples from human infants and bovine calves from organized livestock farms & hospitals in north India, were screened and 16 samples were found positive by PAGE and 6 were positive by RT-PCR. All the samples revealed long electropherotypes by RNA-PAGE. NSP4 gene of BRV & HRV was amplified and yielded PCR product of 725bp. vp7 and VP4 genes of BRV & HRV were also amplified and yielded PCR product of 1011bp (VP7of BRV&HRV), 864bp (VP4 of BRV) and 877bp(vp4 of HRV). PCR Amplified NSP4 gene amplicons were cloned and screened by touch PCR. The positive recombinant bacterial colonies were subjected to sequencing. The sequences were analysed using BlastN and aligned by Clustal X. The percent identity and distance matrices of the partial NSP4 gene sequences with representatives of representative NSP4 genotypes were generated by MEGA version 4. Phylogenetic trees were constructed by analyzing nucleotide sequences by MEGA 4 software. By phylogenic and evolutionary analysis the genotype of buffalo, cattle, and human rotaviruses were classified as genotype A, A and B. By Phylogenetic analysis it was also confirmed that buffalo and cattle rotaviruses were clustered with Simian, equine, human and lamb rotaviruses. By sequence analysis it may be stated that there is interspecies transmission of rotaviruses among different host species. These results may have better implications for the design and implementation of successful h rotavirus vaccine strategies.