Prevalence, types, and RNA concentrations of human parechoviruses in patients with acute enteritis, including a sixth parechovirus type

Laboratory of Virology, Department of Microbiological Consumer Protection, Institute of Hygiene and the Environment, Hamburg, Germany, Clinical Virology Group, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany, Prof. Hess Childrens Hospital, Klinikum Bremen Mitte, Bremen, Germany

^* To whom correspondence should be addressed. Email: drosten{at}virology-bonn.de.

	Abstract

Parechovirus epidemiology and disease association are not fully understood. Real-time RT-PCR for all HPeV was applied on stool samples from two groups of patients. Both contained patients with acute enteritis of all age groups, seen during one full year. Patients with norovirus, adenovirus, enterovirus, astrovirus and rotavirus infection were excluded. In 118 patients from outbreak and hospital settings, no HPeV was detected. In a prospective study group of 499 non-hospitalized patients, detection rate was 1.6%. One virus-positive patient occurred in 39 control patients. Positive samples occurred only in summer and autumn. Only one patient had accompanying respiratory symptoms. Association with travel or animal contact was not found. All positive patients except one were <2 years of age, with neutral gender ratio. In children <2 years of age, detection rate was 11.6% (7 of 60 children). The range of viral loads was 3170 – 503,377,290 copies per gram or millilitre of stool. One of the highest viral loads occurred in a control child without symptoms at the time of testing.

Phylogenetic analysis showed mainly contemporary HPeV1 strains in our patients, but also a separate new lineage of HPeV1 in evolutionary transition from the historical prototype strain. Moreover, a novel sixth HPeV type was identified. Full genome analysis of two viruses revealed recombination between HPeV1 and 3 in one, and HPeV6 and 1 in another. HPeV seems relevant in children <2 years and specific RT-PCR for HPeV should be included in enteritis screening.