Category: Automation and High-Throughput Technologies
Detecting viruses like West Nile and Zika in field-caught mosquitoes provides vector control agencies with an early warning that focuses mosquito abatement efforts and safeguards public health. However, conventional arbovirus surveillance is labor-intensive and slow. Agencies currently rely upon baited traps, manual insect sorting, and laboratory-intensive real-time PCR detection of viruses that altogether take 2 weeks to complete. Sandia has developed and field tested an automated mosquito-borne virus sentinel, ArboWatch, that reduces the cycle time in detecting and implementing a response to a mosquito born virus from 2 weeks to near real time. This increases state and local governments’ capability to prevent disease outbreaks before they occur and at lower cost. Housed in a small Pelican™ case for field deployment, the ArboWatch is based upon the principle of passive sugar baiting, in which mosquitoes feed upon scented sugar baits and leave behind traces of saliva in the process of feeding. If mosquitoes have a disseminated infection that has spread to the salivary glands, virus is deposited with the saliva, and viral RNA can be detected from rehydrated sugar baits by molecular assays. ArboWatch provides a self-contained microfluidic assay cartridge pre-loaded with a sugar bait and stabilized reagents to perform an automated molecular detection assay for viruses. The system relies upon RT-LAMP instead of qRT-PCR, and employs a novel endpoint detection chemistry (QUASR) that provides exceptionally bright fluorescence signals while simultaneously reducing false-positive rates. These innovations improve detection robustness, eliminate sample preparation, and reduce power consumption. Each ArboWatch system comes preloaded with up to 30 assay cartridges, and can be programmed to provide results on a flexible basis (daily, every 2 days, etc.). The ArboWatch system is fully automated. A linear motion control system conveys the assay cartridges, and linear actuators drive fluids. Additional components include a magnetic mixer, a heater, a linear diode array for fluorescence detection, a microcontroller, and a wireless transmitter to communicate assay results. A rechargeable battery pack and solar panel provide power for extended deployments. A field trial of a network of ArboWatch units was conducted in the summer of 2017, for surveillance of West Nile virus and St. Louis encephalitis virus (both transmitted by Culex mosquitoes). RT-LAMP assays for this panel of California-relevant arboviruses yield results in under 30 minutes, and are sensitive to 0.1 PFU/reaction (comparable to qRT-PCR). Results are fed into the DTRA-developed Biosurveillance Ecosystem (BSVE), and overlaid with model predictions of vector abundance, allowing assessment of disease risk in near-real time. ArboWatch is poised to revolutionize arbovirus surveillance both in remote locations where traditional surveillance is unfeasible and in populated areas. Extension of the technology to Aedes aegypti mosquitoes for diseases such as dengue and Zika is planned.
Cameron Ball– Senior Member of Technical Staff, Sandia National Laboratories, Livermore, California
Senior Member of Technical Staff
Sandia National Laboratories
I take a proactive, targeted approach to improving medical diagnostic, prevention, and treatment technologies. With 10 years of experience as a biomedical engineer, I bring a command of cross-functional engineering skills and fundamental science knowledge to bear on complex problems in biological systems.