This Small Business Innovation Research (SBIR) Phase II project proposes to develop and validate a non-invasive, multiplex urine dipstick for clinical diagnosis of Acute Febrile Illness (AFI) caused by polymicrobial infections. The target diseases include leptospirosis, typhoid fever, dengue, as well as Plasmodium falciparum and P. vivax malaria, responsible for ~229M AFI's and >800,000 deaths a year worldwide. Current diagnostic tools are invasive, technically complex, and thus not suitable in tropical and subtropical countries where these diseases are most prevalent, especially in rural and point-of-care settings where blood testing is impractical. The Phase I project successfully developed and validated pathogen-specific recombinant antibody reagents that demonstrated diagnostic potential in urine. This Phase II project envisages two broad objectives: (i) detailed characterization of the recombinant monoclonal antibody reagents to validate their individual and collective diagnostic utility; and (ii) to develop and validate a multiplex dipstick test device for concurrent detection of a set of leading causes of acute fever in a single urine sample. The deliverable will be a simple diagnostic device with the potential to diagnose either/both Plasmodium falciparum, Plasmodium vivax and Leptospira, which combines the need to improve specific diagnosis of AFI with the need to address alternative causes of acute fever.
The broader impact/commercial potential of this project, if successful, will be the delivery of a rapid diagnostic tool that addresses a major challenge faced by people in low resource settings with high burdens of global health diseases, i.e. how to manage acute fever without the benefit of rapid differential diagnostic tests. Although individual tests for each potential cause of fever would be beneficial, it is often not feasible or practical to rapidly select, run, and interpret multiple individual tests in these settings. The cost implications for such individual testing also will be prohibitive. Therefore, a multiplex rapid device as envisaged here that will evaluate groups of symptomatically related febrile diseases is urgently needed. It will offer both medical and logistical benefits for rapid testing of leading causes of acute febrile illness in a single urine sample. It will deliver a single answer multi-disease diagnostic with broader impact, and offer differential diagnosis through a multiplexed assay rather than individual testing, most suitable in resource limited settings where diagnostic laboratory capacities are limited. This multiplex urine dipstick test is designed to be a foundational platform device to which other diagnostic reagents for acute fever can be iteratively added to suit a particular region.
In many countries, fever is a constant sign of illness, but this could be caused by many different diseases, which require specific line of treatment. Therefore, it is important to be able to tell in a simple and fast manner what the cause of fever is using a rapid diagnostic test that can 'multi-task' in such manner, to enable prompt targeted treatment. The need for such simple tool for the diagnosis of a specific cause of fever is critical especially in settings with limited laboratory diagnostic services. As envisaged in this project, such test was intended to be antibody-based and involve multiple antibody reagents that individually target the detection of a specific disease. This means that from the same patient urine sample, one will be able to tell if the fever is caused by any of malaria, typhoid fever, dengue or leptospirosis, which constitute the commonest causes of fever in many developing countries where these diseases are prevalent. In this project, we developed and validated the antibody reagents needed for developing a multiplex test that can tell the cause of fever from different diseases. We applied a novel approach for antibody design for design and development of these diagnostic reagents. Our next steps are now to begin to further improve and format these reagents for clinical use. For this to happen effectively, we must be able to procure well-characterized clinical/patient urine samples. In our experience during the implementation of this Phase 2 project, this was a major source of delay. We anticipate to seek additional support from the NSF in the future to be able to further develop/optimize these important reagents, for rapid delivery of the test to the marketplace.