Rotaviruses

Acute infectious diarrhea is one of the two most frequent diseases of young children. Until the early 1970s, numerous unsuccessful attempts were made to grow viral agents responsible for acute infectious diarrhea of children. The etiologic agent of epizootic diarrhea of infant mice (EDIM) was identified by electron microscopy in 1963 (1). Nonetheless, it was only with the discovery of the virus responsible for calf scours (with this same approach) in 1969 by Mebus et al (2) and of the human Norwalk virus by Kapikian et al (3) in 1972 that the methodology for identification of the viruses responsible for severe diarrhea in children was established. Using electron microscopy, Bishop et al (4) identified the first human rotavirus in an intestinal biopsy from a child with diarrhea. At roughly the same time, other groups used immune electron microscopy to identify the enteric caliciviruses and astroviruses, viruses that were also difficult to grow in vitro, as additional causes of acute infectious diarrhea in children and adults. Shortly after the discovery of human rotaviruses, it was realized that the EDIM virus and the calf scours virus were morphologically and antigenically related, and all these strains were grouped in the genus rotavirus. In rapid order, rotaviruses were shown to be among the most important pathogens of acute diarrhea in the young of many animals, including humans.