Unexpected detection of simian SA11-human reassortant strains of rotavirus G3P[8] genotype from diarrhea epidemic among tribal children of Western India.

This investigation is in continuation with the earlier studies on diarrhea epidemic due to rotavirus, that occurred at Jawhar western India, among tribal children during Dec 2000-Jan 2001 published by National Institute of Virology, Pune. Three rotavirus strains were isolated in cell culture from fecal specimens of affected children. Monoclonal antibody ELISA and RT-PCR typed the isolates as G3P [8]. Two isolates agglutinated guinea pig erythrocytes thereby indicating their animal origin. Antiserum against simian G3, SA11 neutralized both the isolates largely than antiserum against human G3 (YO). Nucleotide sequencing of VP7 gene, nested PCR product of three isolates, and two original fecal specimens showed 100% identity with both simian G3, SA11 prototype and ROSVP7, SA11 strains whereas, lower identity (82%) with human G3 (YO) strain. Partial sequence analysis of the VP4 gene of fecal specimen FS-006964 & isolate I-006964 showed 99% identity with G1P[8] strain, while 80% identity with simian G3P[2], SA11 strain. Thus, the strains appeared to be reassortants between human and simian origin. Serological studies further supported the identity of the causative agent as simian G3, SA11 like strains. Neutralizing antibody titers at very low level against simian G3, SA11 as well as human G3 (YO) strains among the population at Jawhar suggested an overall lack of immunity against the virus. Seroconversion against simian G3, SA11 was shown by six out of seven child patients. Thus, simian G3, SA11 like strains are claimed for the first time as etiological agents of diarrhea in humans. (c) 2005 Wiley-Liss, Inc.