GENETIC AND ANTIGENIC CHARACTERIZATION OF A SEROTYPE G6 HUMAN ROTAVIRUS ISOLATED IN MELBOURNE, AUSTRALIA

An unusual rotavirus strain, MG6, was isolated from a 16-month-old chi ld admitted to hospital with acute gastroenteritis. The virus could no t be serotyped (G-typed) by enzyme immunoassay using sta nda rd reagen ts specific for common serotypes of human Group A rotaviruses. Nucleot ide sequencing of cDNA derived from the gene encoding the outer capsid protein, VP7, and deduction of the VP7 amino acid sequence indicated that this strain belonged to serotype G6, a serotype normally associat ed with viruses causing disease in cattle. This was confirmed by polym erase chain reaction typing and enzyme immunoassay using a G6-specific monoclonal antibody. The VP4 genotype of MG6 was determined by hybrid ization of its VP4 cDNA to genom ic RNA isolated from standard strains of defined P-types. This analysis, confirmed by deduced amino acid se quence analysis, classified MG6 into the novel genotype P13. MG6, ther efore, is related to the previously described G6P13 human strain PA169 , isolated in Italy. The emergence of strain MG6, the first human G6 r otavirus identified in Australia, provides further evidence of reassor tment between human and animal rotaviruses. (C) 1995 Wiley-Liss, Inc.