Diversity of G-type and P-type of human and animal rotaviruses and its genetic background

Rotavirus is a major etiologic agent of gastroenteritis in infants and young children worldwide, and also in variety of mammals and birds. The most prevalent species of rotavirus, i.e., group A rotavirus is highly diverse antigenically and genetically. Two major outer capsid proteins of rotavirus, VP7 and VP4, contain neutralization antigens. Based on the antigenicities and gene sequence diversity of these proteins, two independent serotypes (G-serotype and P-serotype) and genotypes (G-type and P-type) have been discriminated. Sixteen G-types and 28 P-types have been reported so far. Prevalence of G-type and P-type is different depending on animal species, region/country, and seasons/years. A large number of epidemiologic investigations have revealed occurrence of globally emerging types of rotavirus, and recent phylogenetic studies have provided suggestions for origin of these viruses and their transmission. Present status of prevalence, distribution, and diversity of rotavirus G-type and P-type is discussed with molecular epidemiologic backgrounds.