Development of a SYBR-Green I quantitative PCR assay for the detection and genotyping of different hantaviruses

Hemorrhagic fever with renal syndrome (HFRS) is a severe, viral zoonotic disease which occurs worldwide, particularly in Asia and Europe. In China, the Hantaan virus (HTNV) and the Seoul virus (SEOV) are known to be the most prevalent causative agents of HFRS. Since no protective vaccines or effective treatments are available for human use, accurate and reliable diagnostic methods are essential for disease surveillance. In the present study, the viral loads in cell culture supernatant, infected mice blood and clinical serum samples were quantified using the SYBR-Green I-based reverse transcription-quantitiative polymerase chain reaction (RT-qPCR) assay, which targeted the S gene sequence of the HTNV and SEOV genomes. The cRNA of these two viruses were synthesized as a positive control and 10-fold serially diluted from 1x10(5) to 1x10(0) copies/mu l. Standard curves were generated by plotting the mean cycle threshold (Ct) values versus copy numbers. The standard curve of HTNV had a correlation coefficient (R-2) of 0.994, efficiency of amplification (E) of 101.9%, and the slope of -3.278, whereas that of SEOV had an R-2 of 0.993, E of 104.8%, and the slope of -3.212. The minimum detection limit of the RT-qPCR assay for HTNV and SEOV was 10(1) copies/mu l. Two qPCR assays were successfully established for the detection of HTNV and SEOV, respectively. Taken together, these findings demonstrate that using the SYBR-Green I-based RT-qPCR assay, the HTNV and SEOV may be genotyped precisely without cross-reactivity. Furthermore, viral RNA may be detected and quantified in cells, mice and infected individuals, which may be useful in epidemiological studies as well as for early monitoring and further preventative treatment against SEOV and HTNV-induced diseases.