NEW YORK (Reuters Health) – A newly developed reverse transcription recombinase polymerase amplification (RT-RPA) assay shows promise as a point-of-care diagnostic for Chikungunya virus (CHIKV), researchers report.
CHIKV is transmitted to humans by Aedes mosquitoes, which also transmit the Dengue and Zika viruses. The virus is “currently transmitted in about 60 countries . . . (and) causes acute flu-like symptoms and in many cases prolonged musculoskeletal and joint pain,” write Dr. Matthias Niedrig of the Robert Koch Institute in Berlin, Germany and colleagues.
Usually, the infection is detected using RT-PCR or ELISA, “which are not suitable for point-of-care diagnosis,” they note.
As reported online in PLOS Neglected Tropical Diseases, the team developed and tested a rapid, inexpensive and easily deployable alternative based on RT-RPA technology.
Within 15 minutes, the new diagnostic reliably detected and identified 18 different CHIKV strains from the three known CHIKV genotypes.
Dr. Niedrig told Reuters Health, “The clinical sensitivity and specificity of the CHIKV RT-RPA assay was assessed with plasma samples from 58 suspect Chikungunya Fever cases and compared to two CHIKV-specific real-time RT-PCR tests during a field trial in Bangkok, Thailand.”
Both RT-PCR tests detected 36 out of 58 positive samples, he said by email. By comparison, “RT-RPA correctly identified all 36 positive samples and correctly identified the 22 negative samples with 100% sensitivity and specificity.”
“Additionally, we tested 20 sera from acute CHIK patients from France,” he continued. “All three methods efficiently detected 20 out of 20 CHIKV positive samples.”
No cross-reactivity was detected to other alphaviruses and arboviruses, except O’nyong’nyong virus, which could be differentiated by modifying the primer, according to the authors.
Dr. Niedrig observed, “Although the first results look very promising, the evaluation has to be enlarged with a higher number of clinical samples to confirm the robustness and usability” of the assay.
“Since we have evaluated the RT-RPA technology successfully also for the diagnosis of other emerging viruses such Ebola, Yellow Fever, Dengue and Zika, we are sure that the advantage of this technology for quicker and reliable diagnosis will be accepted as a serious alternative . . . to real time PCR,” Dr. Niedrig concluded.
Dr. Daniel Caplivski, an infectious diseases specialist at Mount Sinai Hospital in New York City, told Reuters Health, “Chikungunya has become an emerging problem in the United States because we have a lot more travelers since 2013, when there was a major outbreak in the Caribbean that quickly spread to the Americas.”