High Prevalence of Human Parechovirus (HPeV) Genotypes in the Amsterdam Region and Identification of Specific HPeV Variants by Direct Genotyping of Stool Samples

Human parechoviruses (HPeV) are widespread pathogens belonging to the Picornavirus family. Six genotypes, which have predominantly been isolated from children, are known. Data on prevalence of HPeV genotypes are generally based on cell culture, which may underestimate the prevalence of certain HPeV strains that are difficult to grow. We studied 1,824 stool samples from 1,379 children (<5 years old) sent to the Academic Medical Center, Amsterdam, The Netherlands, between 2004 and 2006. Samples were screened using specific human enterovirus (HEV) and HPeV real-time PCRs based on the 5' untranslated region. A high percentage of HPeV infections (16.3%), comparable to the percentage of HEV infections (18.4%), were found by PCR in stool samples. HPeV-positive stool samples were directly genotyped based on the VP1 region for the first time to avoid a culture bias. HPeV1 was found to be the most prevalent type. The majority of the HPeV1 strains clustered separately from the prototype strain, Harris, which has not been reported to circulate lately. However, we could identify three strains as HPeV1 Harris. HPeV3 was identified as the second most predominant type during 2004 and 2006 but was not found in 2005. HPeV4 to -6 were found in smaller numbers. One strain could not be associated with a known HPeV type (VP1 gene nucleotide similarity: 71%), possibly indicating a new genotype. Also, we report the first identification of three HPeV5 strains and one HPeV1 strain with a different motif at the C-terminal end of VP1, where the arginine-glycine-aspartic acid (RGD) motif is normally located.