A rare genotype G6P[9] was identified in two human group A rotavirus strains designated as KF14 and KF17, that were detected in stool specimens from children with diarrhea in Japan. VP7 gene sequences of these two strains were identical and genetically closely related to G6 human rotavirus strains reported in European countries and the United States. To our knowledge, this is the first report of detection of a G6 human rotavirus in Japan. For further genetic analysis to elucidate the origin of the G6 rotavirus, nearly full-length sequences of all 11 RNA segments were determined for the KF17 strain. The complete genomic constellation of KF17 was determined as G6-P[9]-I2-R2-C2-M2-A3-N2-T3-E3-H3, a novel genotype constellation for human rotavirus. Phylogenetic analysis indicated that VP6, VP1-3, and NSP2 genes of KF17 clustered with bovine-like G6 human strains and some animal strains into sub-lineages distinct from those of common DS-1-like G2 human rotaviruses. On the other hand, KF17 genes encoding VP4, NSP1, and NSP3-5 showed high sequence identities to the human G3P[9] strain AU-1, and clustered with AU-1 and some feline strains within the same lineage. These findings suggested that the G6P[9] human rotavirus detected in Japan may have occurred through reassortment among uncommon bovine-like human rotaviruses and human/feline AU-1-like rotaviruses.

We present here the unusual case of a male newborn infant who showed progressive severe cholestasis. The infant's gestational age was 37 weeks, and his birth weight was 2134 g. His serum level of direct bilirubin gradually increased from the 6th day of life and reached 257.5 micromol/L on the 22nd day of life. We could not find any cause for his cholestasis, but his serum level of ferritin was extremely elevated at 9211.0 ng/mL. Because we felt that his clinical condition might be related to hypercytokinemia caused by an immunologic reaction, steroid pulse therapy and cyclosporine were administered. His condition improved, and his direct bilirubin and ferritin levels declined. From the investigation of his cytokine profile, we found a preferentially elevated level of serum interleukin 17 (IL-17) (96.1 pg/mL) and high level of chemokines IL-8 and macrophage inflammatory protein 1beta. The IL-17 level gradually decreased to 7.5 pg/mL by the 124th day of life. The infant was successfully discharged from the children's hospital but later developed epilepsy at 11 months and asthma at 1 year, 2 months of age. Although we have not yet reached a definitive diagnosis, this case may be the first to show a relationship between cholestasis and an elevated serum IL-17 level in the neonatal period.

Background: Serious gastrointestinal infection of Rotavirus (RV) is usually prevalent during winter months and often seen in infants and young children. Studies on genotypes of prevalent rotavirus strains are quite important for preventing infection, developing vaccines, and its evaluation. While at least 11 G genotypes have been isolated from humans, G1, G2, G3, G4, and emerging G9 are major genotypes of human RV. Although G6 human rotavirus is quite rare, it is the major type among rotaviruses from cattle. In this study we investigated the characteristics and origin of bovine RV strains from the children of the Nasu district, Tochigi, Japan.