Rotavirus, Caliciviruses, Astroviruses, Enteric Adenoviruses, and Other Viruses Causing Acute Gastroenteritis�

Abstract

Acute gastroenteritis is an important cause of morbidity and mortality worldwide, particularly among young children living in developing countries. Among the several causes of gastroenteritis (chemical, bacterial, and parasitic), viral pathogens play an important role. The role of four viral agents, rotaviruses, caliciviruses, astroviruses, and enteric adenoviruses, in causing gastroenteritis in humans is well established. Rotaviruses are members of the Rotavirus genus within the Reoviridae family, which also contains 10 other genera. Cell culture is not used for the diagnosis of rotavirus disease, since human rotaviruses are difficult to cultivate from clinical specimens. Caliciviruses are single-stranded, positive-sense RNA viruses with a broad host range and disease manifestation, such as respiratory disease in cats, vesicular disease in swine, and hemorrhagic disease in rabbits. The first astroviruses were identified in diarrhea stool specimens from children in 1975 by electron microscopy (EM). Later astroviruses have been isolated from numerous animal species and recently grouped into two genera, Mamastrovirus and Avastrovirus, within the Astroviridae family. Human astrovirus infections occur worldwide and are primarily associated with pediatric disease. Human adenoviruses have been linked with a number of diseases, including respiratory illness, conjunctivitis, and diarrhea. They are classified into the Adenoviridae family, Mastadenovirus genus. The recent introduction of rotavirus vaccines to the international markets is a promising start and hopefully will be followed by similar strategies for other viral causes of acute gastroenteritis. This chapter also talks about other enteropathogenic viruses such as coronaviruses and toroviruses, picobirnaviruses, and aichi virus.