An electron microscopical investigation of small round viruses in non-bacterial gastroenteritis.

Small round viruses implied in non-bacterial gastroenteritis were observed by electron microscope in stool specimens collected from 1993 to 1996. The specimens relative to 1981 were re-examined. The identified viruses are astroviruses (n = 6), caliciviruses (n = 7), Norwalk-like viruses (n = 34) and Parvoviruses (n = 6). Immunoelectron microscopy (IEM) and solid-phase immunoelectron microscopy (SPIEM) were used in order to verify serological differences existing among Norwalk-like viruses from different outbreaks. The results obtained suggest a possible circulation, in Liguria, of two serotypes of antigenically different viruses in the period considered.