Circulating of human bocavirus 1, 2, 3, and 4 in pediatric patients with acute gastroenteritis in Thailand.

Human bocavirus (HBoV) is a newly identified human parvovirus that associated with respiratory and gastrointestinal diseases. Epidemiological surveillance of HBoV was conducted on fecal specimens collected from hospitalized children with diarrhea in Chiang Mai, Thailand in 2011. Among a total of 222 fecal specimens tested, 17 (7.7%) were positive for HBoV by PCR. Of the 17 HBoV positive samples, double- or triple-infections together with other enteric viruses were found in 10 (58.8%) pediatric patients, while monoinfection with HBoV alone was detected in seven (41.2%) cases. Mixed infection among HBoV with norovirus GII was frequently observed in this population. The partial VP1 nucleotide sequences of all 17 HBoV strains demonstrated that all four species of HBoV were found in the specimens tested. Eleven strains were HBoV1. Other three strains showed the sequence identity with HBoV2, which were most closely related to the HBoV2A. In addition, other two HBoV strains showed the highest level of nucleotide sequence identity with the HBoV3. It was surprisingly to observe that one Thai HBoV strain showed a unique characteristic similar to the HBoV4, a rare species of HBoV found in acute gastroenteritis patients. In summary, this study presents the genetic background information of HBoV circulated in acute gastroenteritis children in Chiang Mai, Thailand and it was clearly demonstrated that HBoVs circulated in this area were genetically diverse as all four species of HBoVs (HBoV1-4) were detected in the fecal specimens collected from pediatric patients admitted to the hospitals in this area.