Development and evaluation of a real-time RT-PCR assay for Sindbis virus detection.

Sindbis virus (SINV) is an arthropod-borne alphavirus found widely in Eurasia, Africa and Oceania. Clinical SINV infection, characterized by rash and arthritis, is reported primarily in Northern Europe. The laboratory diagnosis of SINV infection is based currently on serology. A one-step TaqMan(®) real-time RT-PCR assay was developed for the detection of SINV and evaluated its clinical performance with acute-phase serum samples. The specificity and sensitivity of the real-time PCR assay were assessed using cell cultured Finnish SINV strains. The applicability of the assay for diagnostic use was evaluated using 58 serum samples from patients infected with SINV. The real-time RT-PCR assay was specific and sensitive for the detection of SINV in cell culture supernatants with a 95% detection limit of 9 genome copies/reaction determined by probit analysis. However, in the assay only 7/58 (12%) of serum samples were positive of which two were also positive by conventional nested PCR assay and none by virus isolation. This novel assay is specific and sensitive for detection of SINV and can be used for example for screening SINV in wildlife. However, molecular diagnostic techniques using serum samples seem to be of limited value for the diagnosis of human SINV infection due to the short and low viraemia of infection with SINV.