image: This is an infographic showing Zika virus prevalence in the Americas. view more
Credit: [Credit: Carla Schaffer / Chotiwan at al. / AAAS]
A fast, highly sensitive, and inexpensive new test not only detects Zika virus in mosquitoes and human bodily fluids, but can also distinguish between African and Asian strains -- a result that could improve efforts to more effectively track the virus' spread. The Asian-lineage strain of Zika virus, which has been implicated in causing severe birth defects such as microcephaly, rapidly infiltrated the Americas after its introduction in 2015, transmitted by mosquito species in the genus Aedes. According to recent Centers for Disease Control estimates, 5,238 cases of Zika virus infection have been reported in the United States, 223 of which were presumed to have been acquired locally. Nunya Chotiwan et al. devised an assay to directly detect Zika virus from mosquitoes and several different types of unprocessed clinical samples (including human blood, saliva, and semen). They amplified Zika virus genomes using a specialized technique called LAMP, an approach that proved comparably sensitive to the current gold-standard detection method, qRT-PCR. Unlike qRT-PCR, however, LAMP does not require costly reagents. Importantly, LAMP did not yield false-positives for closely-related pathogens such as Dengue virus and Chikungunya virus. The researchers validated the LAMP test using virus artificially spiked into materials obtained from healthy individuals, and also in clinical specimens collected from confirmed cases of Zika virus infection. LAMP was also sufficiently sensitive to identify one single infected mosquito from a collection pool of 50 uninfected insects. The authors say that LAMP's minimal processing requirements and accelerated turnaround time will be valuable for Zika virus surveillance and control.
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Journal
Science Translational Medicine