Y-028. Identification of Genogroup C Rhinoviruses in California Based on the Analysis of the 5' Noncoding Region

D. Kiang1, S. Yagi1, J. Louie1, H. Boushey2, D. Schnurr1;
1California Dept. of Pub. Hlth. (CDPH), Richmond, CA, 2Univ. of California, San Francisco, CA.

Background: Human rhinoviruses (HRVs), members of the Picornaviridae family, are the most frequent etiological agents of the common cold. HRVs are increasingly being recognized for their association with severe lower respiratory tract infections in infants, elderly, and immunocompromised individuals and have a role in the exacerbation of asthma, cystic fibrosis and chronic bronchiolitis. HRVs are non-enveloped, single-stranded, positive-polarity RNA viruses with a genome of 7.1 kb which includes a 5’ noncoding region (5’NCR). Methods: As a state reference laboratory, the CDPH VRDL receives approximately 1000 respiratory specimens annually for testing for a broad variety of viral respiratory pathogens. We developed a sensitive molecular assay targeting a 390 bp region of the 5’NCR that is able to distinguish among all prototype strains of rhinovirus. This assay is capable of direct detection of HRV from clinical specimens, and was used to further characterize respiratory specimens that tested positive for rhinovirus by real-time PCR. Results: Through phylogenetic analysis of the sequences in this region, we identified a novel group of rhinovirus, genogroup C, in five cases. Clinical information was available on four patients; all were severely ill and required hospitalization in intensive care for severe respiratory tract infections (3 cases) and encephalitis (1 case). Conclusions: Genogroup C rhinovirus is circulating in California and can be associated with severe clinical illness in children. This novel group of rhinoviruses has been identified recently in association with severe respiratory tract infection among children in Wisconsin. It remains to be determined whether these HRVs are related to HRV ‘X’ characterized among volunteers with upper respiratory tract infection in UCSF or to HRV X identified among children with severe respiratory tract infection in Germany, both of which have been characterized using VP4-VP2. This genogroup is distinct from a novel sublineage, HRV-A2 identified in New York and Australia, as well as a proposed HRV-C from Hong Kong. Failure of these viruses to be isolated in cell culture is an indicator of phenotypic differences in this novel genogroup.

259/Y. Emerging Infectious Diseases

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