Detection and Molecular Characterization of Avian Rotaviruses in Broiler Farms in Guilan

Avian rotaviruses are one of the important agents of enteritis in birds and have a worldwide distribution. These viruses have an important role in runting and stunting syndrome in chickens. The aim of this study was detection and molecular characterization of avian rotaviruses in broiler farms in Guilan province. In this study, 100 samples were collected on different farms from the intestines of healthy and diseased broiler chickens and tested by RT-PCR targeting of the NSP4 gene. Sequencing of NSP4 gene has been used for characterization of detected viruses. Avian rotaviruses were detected in 46% of samples by RT-PCR. Partial sequencing of seven NSP4 genes and phylogenetic analysis indicated that the viruses belonged to group A avian rotaviruses and were 97.52% to 100% homologous. Sequence identity between viruses with previous chicken rotavirus sequences was 31.68% to 99.5%. In comparison with turkey rotavirus Ty-1 and pigeon rotavirus, the homology was 76.98% to 78.22% and 74.75% to 76.98%, respectively. Evident differences were detected between the rotaviruses studied and human and pig rotaviruses with homologies of 31.19% to 38.86% for pig and 47.77% to 48.02% for human viruses. This study was the first molecular characterization of avian rotaviruses in Iran. Results of this study showed that the group A avian rotaviruses are one of the considerable enteric pathogens in broiler chickens of Guilan province. Further study on the whole genome structure could elucidate the evolutionary process of avian rotaviruses circulating in Iran.