First identied in 1973 by electron microscopy in epithelial cells of duodenal mucosal samples from children, rotaviruses (RVs) were soon recognized as a major cause of gastroenteritis in the young of many animal species, including humans.1-3 In humans, RV-associated disease typically occurs in children less than 5 years of age, but RV can infect all ages, including adults4,5; in 2008, an estimated 453,000 deaths worldwide were attributed to RV infection, with most deaths occurring in resource-poor countries.6