Human Enterovirus Genotype C104, China

To the Editor: Human enteroviruses (EVs) are small, nonenveloped RNA viruses belonging to the family Picornaviridae. Approximately 100 EV genotypes have been identified. Recently, EV68 epidemics in respiratory tract infections (RTIs) have been reported worldwide (1,2). Moreover, rarely detected EVs (e.g., EV-C104 and EV-C109) have been increasingly identified in patients with RTIs (3–7), indicating a possible association of EVs with respiratory syndromes. Little is known about the role of EV-C104 in RTIs. EV-C104 has been reported in 3 countries: Switzerland (7 children with pneumonia or otitis media) (3), Italy (3 adults and 4 children with RTIs) (4,7), and Japan (1 adult with an upper RTI [URTI]) (5). We report additional EV-C104 strains in 4 children with lower RTIs and in 1 adult with a URTI in China. To identify EV infections, we collected nasopharyngeal aspirates from 3,108 children (1,963 boys) <14 years of age (median age 12 months; age range 0.3–168 months) who had lower RTIs at admission to Beijing Children's Hospital during March 2007–February 2012. Throat and nasal swab specimens were also collected from 9,232 adults (4,140 men) >15 years of age (median age 35.3 years; age range 15–97 years) with acute RTIs who received treatment at Peking Union Medical College Hospital during August 2006–February 2012. All samples were screened for influenza virus, parainfluenza virus type 1–4, respiratory syncytial virus Because we could not amplify EV-C104 by using primers specific for the viral protein (VP) 1 region (9), we used a reverse transcription PCR to amplify the 5′-untranslated region/ VP4/VP2 gene (10). Amplicons of ≈600 bp were obtained for samples from 5 patients: 4 boys 2–11 months of age (BCH2859A, BCH2892A, BCH2894A, and BCH3034A) and a 30-year-old man (PUMCH12286). BLAST analysis (www.ncbi.nlm.nih. gov) of sequences of these amplicons showed that the 590-nt sequences had 94.0% identity with that of the EV-C104 prototype strain CL-12310945