Molecular Test Rapidly Detects Chikungunya Virus

A novel molecular diagnostic platform with high sensitivity and specificity has been developed for the early detection of the Chikungunya virus (CHIKV).

Chikungunya has reemerged as an important arboviral infection of global health significance and because of lack of a vaccine and effective treatment, rapid diagnosis plays an important role in early clinical management of patients.

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