ABSTRACT

Astroviruses are small, round, nonenveloped viruses typically 25-35  nm in diameter with a positive-sensed, singlestranded RNA genome ranging in length from approximately 6.2 kb (human) to 7.7 kb (duck).1 They are generally classied according to the species they infect, although species crossover has been observed for some astroviruses, for example, astroviruses of chickens have been detected in turkeys.2 Astroviruses have been discovered to infect many species including humans. The rst observations of astroviruses in humans were in 1975 in the feces of children with diarrhea and gastroenteritis by Appleton and Higgens3 and Madeley and Cosgrove, who named this group of viruses because of its characteristic star-like appearance.4