Detecting Parasites

A new fluorescence test being developed by researchers at SRI International, in Menlo Park, Calif., can detect inexpensively and within minutes the presence of a family of parasites that cause several deadly diseases.

The Trypanosomatidae family of parasites causes Chagas disease in Central and South America, sleeping sickness in Africa, and leishmaniasis in millions of people worldwide. The parasite also causes a disease called nagana in cattle and horses.

Current tests require expensive or time-consuming blood analyses or antibody assays. SRI medicinal chemists Ellen D. Beaulieu and Mary Tanga announced at a press conference at the ACS national meeting in San Francisco that their group engineered a family of arsenic-based dyes and identified three that bind to sulfur-based groups in a peptide unique to trypanosomatid parasites. The peptide-dye complex then glows under ultraviolet light.

Within five years, the team hopes to have a "dipstick" test that's cheap and easily transported to poor and developing countries. Beaulieu noted that these diseases are second only to malaria in the number of deaths from parasitic diseases worldwide.