Rotavirus G9P[4] in 3 Countries in Latin America, 2009–2010

To the Editor: Group A rota-viruses are the most common viral cause of acute gastroenteritis in young children. The most frequently detected group A rotavirus genotype coma large number of unusual G-P combinations have been reported, and among these is the rare G9P[4] genotype, which was identified in Brazil in the 1990s (2), and later reported infrequently elsewhere in Latin America (3). In 2010, cases of group A rotavirus gas-troenteritis associated with genotype G9P[4] were reported in Mexico (4). Increases in the incidence of group A rotavirus gastroenteritis were reported In response to these reports of increased group A rotavirus disease, fecal samples collected in Chiapas State, Mexico (in 2010, 30% of the cases in Mexico were from Chi-apas), Guatemala, and Honduras in 2009–2010 that were positive by enzyme immunoassay were sent to the US Centers for Disease Control and Prevention (Atlanta, GA, USA) for characterization. Viral protein 4 (VP4) (P) and VP7 (G) genotyping, nucleotide sequencing, and genotype identification were performed by using consensus and genotype-specific oligonucleotide primers (5), and sequences were subjected to phyloge-netic analyses. VP6 and nonstructural protein 4 (NSP4) genes of selected samples were also sequenced. For 26 samples from Mexico, G9 accounted for ≈90% of all the G types; all samples had mixed P types.