Characterization of genotype P[9]G12 rotavirus strains from Argentina: high similarity with Japanese and Korean G12 strains.

The circulation of the unusual P[9]G12 strains was previously reported in suburban Buenos Aires, Argentina and in Far Eastern Asian countries. To examine genetic relationships of these strains the genes coding VP7, VP4, and NSP1 from two Argentine, one Japanese and one Korean P[9]G12 isolates were sequenced and their overall genome relatedness was determined by liquid hybridization. In addition, liquid hybridization was used to compare this group of strains to the previous G12 isolates L26 and Se585, and prototype Wa, DS-1, and AU-1 strains. The genomes of the Argentinean, Japanese and Korean strains were virtually indistinguishable by hybridization assays, suggesting very high sequence relatedness for all 11 segments. Hybridization assays also demonstrated that these four strains belong to the AU-1 genogroup and that their genetic relationship with rotaviruses L26 and Se585 is limited to the VP7 gene. The VP7, VP4, and NSP1 genes of the Argentinean, Japanese and Korean strains were highly homologous to each other and to Thai strain T152 ( approximately 99% identity). These results together with the report of a similar strain detected during 2003 in Brazil are consistent with a recent importation and dissemination of the G12 strains from Far Eastern countries into South America. Increasing reports from several regions of the world demonstrating a variety of different G12 reassortant strains suggests that routine surveillance for this serotype should be conducted to determine its potential for global emergence.

Epidemiological profile of rotavirus infection in the Republic of Korea: results from prospective surveillance in the Jeongeub District, 1 July 2002 through 30 June 2004.

To facilitate future decisions regarding the usefulness of rotavirus vaccines in the Republic of Korea, active surveillance was conducted in a network of clinics, emergency departments, and hospitals serving Jeongeub District, Korea. Children with diarrhea underwent standard clinical evaluations, and stool specimens were collected to test for the presence of rotavirus. Parents were interviewed to collect demographic and family information. From 1 July 2002 through 30 June 2004, a total of 4106 children, representing 1 (50%) of every 2 children <5 years old in the study population, were evaluated for rotavirus diarrhea. Of the 2232 stool specimens obtained throughout the year, 460 (20.6%) were rotavirus positive; however, the monthly prevalence of rotavirus infection peaked at 49.5% in February 2004. Of the 460 rotavirus-positive stool specimens, 366 were obtained from children who visited outpatient clinics, and 94 were obtained from children who were hospitalized. By extrapolating the proportion of rotavirus-positive patients to all children with diarrhea in the surveillance system, we calculate that 882 children in Jeongeub District had rotavirus infection (which would predict that there would be 702 associated clinic visits and 180 hospitalizations). Genotyping of rotavirus strains showed that 39% of strains were type G9P[8], 24% were type G1P[8], 17% were type G3P[8], and 13% were type G2P[4]. The incidence of rotavirus diarrhea peaked at age 13-24 months, and 94% of cases occurred during the first 3 years of life. The annual incidence of all rotavirus disease-associated outcomes was 56.9 cases/1000 children <5 years old (95% confidence interval [CI], 51.9-62.2 cases/1000 children <5 years old). The incidence of rotavirus disease-associated hospitalizations was 11.6 cases/1000 children <5 years old (95% CI, 9.5-14.2 cases/1000 children <5 years old). In Korea, diarrhea is common during childhood, and the incidence of diarrhea due to rotavirus infection suggests that improved programs for the prevention and control of both rotavirus diarrhea and diarrhea due to other causes are needed.