Rotaviruses

Rotaviruses belong to the Reoviridae family of icosahedral, nonenveloped, segmented double-stranded RNA (dsRNA) viruses. They are classified into groups (A through E) depending on the presence of cross-reactive epitopes primarily located on the internal structural protein VP6. This chapter mainly talks about group A rotaviruses. It presents details that include epidemiology, clinical manifestations, laboratory diagnosis, prevention and treatment of rotaviruses. Seroprevalence of antibodies for these rotaviruses is relatively high in humans, specially those living in rural areas, suggesting transmission from animals to humans. In humans, the capacity for rotaviruses to reassort influences the generation of serotypic diversity less dramatically than for influenza virus, although reassortment clearly occurs, especially in less developed countries. Rotaviruses have been proposed to enter cells by endocytosis and by direct plasma membrane penetration. Although symptomatic reinfection with rotaviruses seems to be frequent, the severity and number of rotavirus infections diminish with the age of the child, and severe infections seem to be primarily limited to the initial infection. Studies with mice have shown that rotaviruses are inactivated in the stomachs of adult but not newborn mice, which suggests that the development of gastric acid and pepsin secretion may be an important factor in host defense against rotavirus. The relative importance of transplacentally acquired versus breast-feeding-acquired antibodies in protection against rotaviruses in children is not clear. Precaution should be exercised in disinfection of surfaces thought to be contaminated with rotavirus, since rotaviruses have been shown to be highly resistant to many commonly used disinfectants.