Epidemiology of WU polyomavirus infection in children with acute respiratory disease and the virus genetic characteristics in Hangzhou

Objective To understand the epidemiological characteristics of WU polyomavirus (WUPyV) infection in children with acute respiratory disease and genotype of the virus in Hangzhou. Methods Nasopharyngeal aspirate specimens were collected from patients with acute respiratory tract infection after admission to the Children's Hospital of Zhejiang University School of Medicine from March 2011 to Junuary 2013. WUPyVs were detected by PCR that targeted a fragment in the VP2-encoding region and genotyped by using the VP2/1 interface typing method. A representative WUPyV isolate was then selected for genome sequencing. Results A total of 722 specimens were collected,in which 10 (1.4%) were detected to be WUPyV positive. WUPyV infection mainly occurred in summer, autumn and winter. The average age of children infected with WUPyV was 13.6 months. The male to female ratio of the cases was 9:1, the difference had no statistical significance (P=0.09). The diseases caused by WUPyV infection included pneumonia, laryngitis and bronchiolitis. WUPyV genotype Ia was the prevalent genotype in Hangzhou. The genome of the representative isolate HZ13024 shared high homology of 99.8%-99.9% with the WUPyV sequences in GenBank. Conclusion Respiratory tract infections in children were partly caused by WUPyV infection. Compared with other areas in China, the infection rate of WUPyV was low. WUPyV genotype Ia was the prevalent genotype in Hangzhou.