Isolation of a human pararotavirus.

During a survey of 350 different isolates of human rotaviruses, a single isolate with unique properties was obtained. Unlike all rotaviruses tested this unique isolate failed to react in an ELISA test with antibody directed against the group-specific rotavirus antigen. The morphology of this unusual virus isolate was identical in electron micrographs with other rotaviruses and the virus also contained 11 double-stranded RNA segments characteristic of this virus group. The electrophoretic migration of these RNAs (electrophoretype) in polyacrylamide gels did not coincide with the typical pattern of distinct size classes observed with all human rotaviruses. The unique isolate thus had two distinct properties that distinguish it from human rotaviruses, lack of a group-specific antigen and an atypical electrophoretype of the RNA segments. Based upon this, the new human isolate is given the name pararotavirus to distinguish this new type of virus group. Porcine and chicken pararotaviruses have recently been described with similar properties.