Dipstick Test Being Developed for Trypanosomatidae Family Members

Scientists report on development of a new, simple, and inexpensive three-in-one test to diagnose parasitic diseases that inflict severe illness in low-resource countries.

The three-in-one test for Chagas' disease, leishmaniasis, and "sleeping sickness," or African Trypanosomiasis has passed preliminary tests. All three diseases are closely related members of what are known as the Trypanosomatidae family.

Working together with Mary Tanga, Ph.D., senior director of medicinal chemistry in SRI's Biosciences Division (Menlo Park, CA, USA), Ellen Beaulieu, Ph.D., and colleagues developed special dyes that allow detection of an early disease stage. These dyes do not require sophisticated lab equipment, and can produce results in as little as one hour. Initial tests under laboratory conditions showed that the dyes reveal the presence of the parasite marker and glow in ultraviolet light from a simple, handheld lamp. SRI scientists are improving the sensitivity of the dyes.

The goal is to develop a "dipstick" version of the test that allows detection of the parasite metabolite using a simple paper strip similar to those used in urine tests for diabetes. Such a test could allow health workers in remote areas to diagnose the diseases by dipping the strip in a drop of blood and exposing it to ultraviolet light

"Early diagnosis is the key to improving treatment of these diseases," said Dr. Beaulieu who reported on the test at the 239th National Meeting of the American Chemical Society, held on March 21-25, 2010, in San Francisco (CA, USA). "Diagnosis with conventional tests is difficult in developing countries where these diseases occur. We hope that our low-cost, simple test will play a role in helping poorer parts of the world combat these diseases and the poverty they engender."

A current test for diagnosing the three diseases involves taking a blood sample from a patient and examining it under a microscope for the parasites that cause the diseases. However, the process is complex, requiring medical laboratory equipment and specially trained health care workers. Current blood tests are also time-consuming. In some cases, it can take up to 90 days to confirm results. Other tests detect the parasites using antibodies. But they require expensive electronic equipment that may not be available in remote areas of the developing world.

SRI, a nonprofit corporation, has all of the resources necessary to take R&D from initial discovery to the start of human clinical trials. The company specializes in cancer, immunology and inflammation, infectious disease, and neuroscience

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SRI's Biosciences Division