Clinical application of RT-nested PCR integrated with RFLP in Hantavirus detection and genotyping: a prospective study in Shandong Province, PR China.

ABSTRACT

The aim of the present study was to evaluate the clinical usefulness of applying RT-nested PCR along with RFLP as a method for diagnosis and genotypic differentiation of Hantavirus in the acute-stage sera of HFRS patients as compared to the ELISA technique. A prospective study of patients with suspected HFRS patients was carried out. Sera were collected for serological evaluation by ELISA and RT-nested PCR testing. Primers were selected from the published sequence of the S segment of HTNV strain 76-118 and SEOV strain SR-11, which made it possible to obtain an amplicon of 403 bp by RT-nested PCR. The genotypic differentiations of the RT-nested PCR amplicons were carried out by RFLP. Sequence analyses of the amplicons were used to confirm the accuracy of the results obtained by RFLP. Of the 48 acute-stage sera from suspected HFRS patients, 35 were ELISA-positive while 41 were positive by RT-nested PCR. With Hind III and Hinf I, RFLP profiles of the RT-nested PCR amplicons of the 41 positive sera exhibited two patterns. 33 had RFLP profiles similar to the reference strain R22, and thus belonged to the SEOV type. The other 8 samples which were collected during October-December had RFLP profiles similar to the reference strain 76-118, and thus belonged to the HTNV type. Sequence phylogenetic analysis of RT-nested PCR amplicons revealed sdp1, sdp2 YXL-2008, and sdp3 as close relatives of HTNV strain 76-118, while sdp22 and sdp37 as close relatives of SEOV strain Z37 and strain R22 located in two separate clusters in the phylogenetic tree. These results were identical to those acquired by RFLP. RT-nested PCR integrated with RFLP was a rapid, simple, accurate method for detecting and differentiating the genotypes of Hantavirus in the acute-stage sera of suspected HFRS patients. In Shandong province, the main genotypes of Hantavirus belonged to the SEOV types, while the HTNV types were observed during the autumn-winter season.