Location: Zoonotic and Emerging Disease Research
Project Number: 3022-32000-021-010-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Feb 15, 2024
End Date: Feb 13, 2026
Objective:
This project will aim to explore the concept of development of Sherlock assays for rapid, low resource, point of care testing. Sherlock has developed a single use battery powered molecular diagnostic device that can provide lab-quality results at the point of need with untrained users. At a manufacturing scale of >1M tests per year, we expect costs to be approximately $8 per test. While this is higher than costs for lateral flow antigen or antibody tests, the results are expected to be considerably more accurate. While the final price to the end user will vary based on geographies, a primary goal of Sherlock Biosciences is to enable the distribution of more affordable and accessible technology to globally, and to that end, the, company has established a charitable foundation which will enable us to sell products to LMIC countries essentially at cost while providing Sherlock with both tax incentives and increased manufacturing volumes in our factories, reducing manufacturing costs per device. This project will leverage work supported by USAID to develop a sherlock assay for differential diagnosis of viral hemorrhagic fevers (VHFs). VHFs describe a clinical syndrome potentially induced by a number of pathogens including Ebola virus, Marburg virus, Lassa Fever virus (LFV) and Crimean Congo Hemorrhagic fever (CCHF) virus. Many of these agents are or are believe to be endemic in Africa (and other regions). Recent investments by the global community have led to the development and availability of assays for filoviruses but assays for the other agents have lagged. In phase 1 we will evaluate a previously developed assay for LASFV for suitability for evaluation of samples for blood. If succesful we will develop assays for CCHF and test candidate assays in blood and tick homogenate matrix. In the final phase we will evaluate the assays in the field. The staggered approach is being utilized to minimize risk and cost of development.
Approach:
1) Augment the work on LFV assay w/ blood as a matrix as proof of concept (6 months): USAID/Project Last Mile have partially funded the development of an LF molecular assay and an initial proof of concept demonstration on our device. However, the use of blood as the input to our device remains to be developed. We propose to determine an optimal sample buffer composition, as well as any additional upstream manipulations such as centrifugation or passage through a filter that are required to maximize the matrix tolerance in our amplification of detection assay for LF while maintaining a workflow that will allow untrained users to run the final assay.
2) Develop a CCHFV Assay for use in blood detection (6 months): We propose to use our internal bioinformatics team to design assays for CCHF, develop the assay to a lyophilized format compatible with our device, and demonstrate a ‘proof of concept’ of detection of CCHF in blood following a bench-based workflow known to be compatible with our device, contrived samples consisting of synthetic RNA in blood, and the blood sample prep workflow developed in Aim 1. We will establish the LoD for synthetic CCHFV targets in blood our assay.
3) Demonstration of ticks as a matrix for CCHFV (3 months): The ability to screen ticks for CCHF has great potential to positively impact human health. We propose to test the potential of directly assaying ticks using our platform. We will test both manual and automated methods for preparing crude lysates of ticks, and determine the optimal sample buffer volumes and compositions for addition to the CCHV assay developed in Aim 2 to maximize sensitivity and minimize inhibition from crude lysates. We will also explore the impact of filtering the lysate before addition to the assay. We will establish the LoD for synthetic CCHFV targets in the optimized lysate in our assay. USDA scientists will support identification of ticks and appropriate matix sources as well as conduct field evaluations.
