Phylogenetic characterization and evolution of the VP4 gene of P[9] rotaviruses
Abstract Objectives: Rotavirus is one of the major causes of gastroenteritis in children under 5 years of age and is responsible for over 200,000 deaths annually. Rotavirus can evolve by reassortment, in which gene segments are exchanged between strains of different origins. Rotavirus strains with the P[9] genotype is an example of reassortment, in which the P[9] genotype is from feline species. A number of outbreaks by P[9] strains have been documented in several countries. However, details regarding the epidemiological relationships between the strains remains largly unknown. Therefore, in the present study, genetic characterization and evolutionary analyses were perforemd to gain insight into P[9] strains circulating in different parts of the world. Results: The P[9] strains could be divided into five lineages, and that the common ancestor of currently circulating P[9] strains is around 168 years old. In each lineage, the strains were not only from different countries, but also from different continents. These findings suggest that none of the lineages has a specific region of distribution, and although humans have had interactions with cats for thousands of years, the ancestor of the current P[9] strain is relatively recent.