Title:  Point of Use Diagnostic Tests for Intestinal Protozoans

Agency: DOD       

PI: White and Richards-Kortum, co-PIs

Abstract: Diarrhea remains the 2^nd leading cause of morbidity and mortality among children worldwide and also is common among adults. Cryptosporidiosis is an intestinal parasitic infection that is emerging as a common cause of diarrhea worldwide. The potential for its use in bioterrorism is illustrated by the epidemic that occurred when the Milwaukee water supply became contaminated with the organism. Over 400,000 people became ill during a period of just of a few weeks. Based on this potential to cause large-scale epidemics from contaminated water, Cryptosporidium has been classified as a Class B agent for biodefense. Cryptosporidium is also a major cause of persistent diarrhea among children in developing countries. The increasing recognition of Cryptosporidium as a cause of diarrhea and as a cause of chronic sequelae has led to its recognition as an emerging infectious disease. Despite the fact that the Milwaukee outbreak was clearly tied to Cryptosporidium infection, only a minority of patients had stool studies for Cryptosporidium performed and, among those studied, most tests were negative, leading to delays in recognition of the cause of the epidemic. Similarly, several recent studies employing serodiagnosis and PCR have suggested that current diagnostic tests for cryptosporidiosis miss a substantial proportion of cases. Thus, improved diagnostic tests are needed for cryptosporidiosis. The specific aims for the first year of this project are: 1) To develop an inexpensive, sensitive and specific diagnostic test that can be used for point-of-care diagnosis of cryptosporidiosis. Two strategies will be pursued in parallel to develop miniature sensors to detect both Cryptosporidium antigen and parasite nucleic acid. 2) To assess the sensitivity and specificity of this assay using stools samples obtained in prospective studies of diarrheal disease. To accomplish these goals, we have assembled an interdisciplinary team with proven expertise in areas needed to accomplish these goals. Dr White’s laboratory at UTMB brings expertise in cryptosporidiosis, clinical infectious diseases and parasite molecular biology and has ongoing collaborations with field studies of diarrheal disease. Dr. Richards-Kortum’s Laboratory, Department of Bioengineering at Rice University, has focused on applying micro-fabrication and nanotechnologies to global health problems and has experience in both micro-optical sensors and the use of targeted nanoparticles for molecular diagnostics. After demonstrating success in this proof-of-concept for Cryptosporidium, the long-range goal for the project will be to incorporate similar techniques to develop a simple, inexpensive test that can detect all the major diarrhea-causing protozoan parasites that can be performed at the point-of-care, even in developing countries. These tests will improve the diagnosis and allow improved treatment of diarrhea, which remains a major cause of morbidity and mortality in the world.

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