Multiplexed RT-LAMP Assays in Handheld Devices for In-Situ Detection of Chikungunya, Dengue, Mayaro, and Zika Viruses.

Mosquito-borne viruses pose a significant global health challenge, particularly in resource-limited settings where multiple viruses often cause illnesses with similar symptoms that require different treatment. We introduce the first 7-plex reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay in a hand-held device capable of detecting the presence of Chikungunya virus (CHIKV), dengue virus serotypes (DENV 1-4), Mayaro virus (MAYV), and Zika virus (ZIKV) in a single test. If the result is positive from the single-plex device for the 7-plex assay, 3-plex and 4-plex devices are then used to identify the exact virus within a specimen. In-situ detection is achieved by integrating valve-enabled, paper-based sample preparation with fluorescence detection using a blue LED flashlight as a light source and a yellow plastic film as a filter, allowing visual discrimination between positive and negative samples by the naked eye or by recording images using a smart phone. The detection limits ranged from 2 genome equivalents (GE)/reaction (for ZIKV) to 92 GE/reaction (for DENV-3) across 7 types of viruses when 1 μL of viral RNA was used. We observed 90% overall agreement between the point-of-care (POC) device and lab-based reverse transcription polymerase chain reactions (RT-PCR) when blinded clinical specimens were tested. This assay and device have a potential to address critical surveillance gaps in endemic regions, enabling timely detection of multiple mosquito-borne viruses to guide appropriate clinical management and public health countermeasures in settings where laboratory resources are scarce.