Molecular Test Rapidly Detects Chikungunya Virus

Scientists at the National University of Singapore (Singapore) collected a total of 42 serum samples from 22 CHIKV-infected patients and 20 from uninfected individuals, to evaluate the clinical sensitivity and specificity of the developed test. All of the serum samples were validated using a real-time reverse transcriptase polymerase chain reaction (RT-PCR) detection assay targeting the CHIKV envelope glycoprotein1 gene.

The molecular test uses 2,7-diamino-1,8-naphthyridine derivative (DANP)-labeled cytosine-bulge hairpin primers to amplify the nsP2 region of the CHIKV genome, followed by measurement of the fluorescence emitted from DANP-primer complexes after PCR. RT-PCR was performed using the C1000 thermal cycler (Bio-Rad; Hercules, CA, USA). Samples were assayed after optimization with CHIKV genomic RNA using AccessQuick Reverse Transcription-PCR kit (Promega; Madison, WI, USA).

The detection limit of the assay was 0.01 plaque-forming units per reaction of CHIKV. The primers were highly specific in detecting CHIKV, without any cross-reactivity with the panel of RNA viruses validated in the study. The feasibility of the DANP-coupled hairpin RT-PCR for clinical diagnosis was evaluated using clinical serum samples from CHIKV-infected patients, and the specificity was 100% and the sensitivity was 95.5%.

The authors concluded that the novel DANP-coupled hairpin RT-PCR technology is a simple, rapid, and cost effective detection method for CHIKV. The results from a patient sample evaluation have indicated high clinical sensitivity and specificity of this method. The method can be a useful tool for rapid detection of CHIKV during outbreaks or as a point-of-care molecular assay for acute-phase patient serum samples in many parts of the world. The study was published in the March 2013 issue of the Journal of Molecular Diagnostics.

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National University of Singapore
Bio-Rad
Promega