Zika virus (ZIKV) is a re-emerging flavivirus that poses a significant public health threat. ZIKV exhibits a wide array of non-vector borne human transmission routes, such as sexual transmission, trans-placental transmission and blood transfusion. Detection and surveillance of ZIKV is considered paramount in prevention of major outbreaks. With the majority of cases reported in low-resource locations, simple, low-cost detection methods are considered highly desirable. Here we have developed a sensitive and specific ZIKV diagnostic using reverse transcription recombinase-aided amplification (RT-RAA) coupled with lateral flow strip detection (LFD) targeting the ZIKV NS1 gene. This diagnostic provides high throughput performance and speed without compromising sensitivity and specificity, compared to the gold-standard RT-PCR.
We show our ZIKV RT-RAA-LFD can detect virus at 178,000 TCID50/ml when using kit-extracted ZIKV RNA (MR766) from virus culture supernatant, equivalent to 178 infectious particles per microlitre. Specificity testing confirmed that our test did not detect closely related flaviviruses (Dengue, West Nile, Japanese encephalitis and Yellow Fever viruses) or Chikungunya virus. Contrary to conventional RT-PCR our ZIKV RT-RAA-LFD does not require expensive machinery, specialised laboratory settings or extensively trained personnel. Our current research endeavours are focused on the implementation of a one-step rapid RNA sample processing method to further improve usability in low resource settings, whilst evaluating the sensitivity and specificity in clinical samples such as serum and urine.
Collectively, our data suggested that our ZIKV RT-RAA-LFD diagnostic has the potential to become a sensitive and specific RT-PCR alternative by offering a promising diagnostic tool for resource-limited settings, where ZIKV and several other arboviruses are endemic.
Keywords: Recombinase Aided Amplification (RAA), Zika Virus (ZIKV), Lateral Flow Strip Detection (LFD), Point-of-care (POC).