Weil battles tropical diseases worldwide

Research promises help and hope for victims of parasitic scourges

Gary J. Weil, M.D., discusses nematode morphology with Shelley Michalski, a graduate student in molecular microbiology.

Traveling to exotic locations and studying tropical diseases are part of the daily routine for Gary J. Weil, M.D., professor of medicine and associate professor of molecular microbiology at the School of Medicine.

Weil's work has taken him to many areas of the world, though his field studies have been concentrated in Egypt, India, and Nigeria, where large numbers of people suffer with roundworm parasites that cause the deforming and disabling diseases known as lymphatic filariasis, or elephantiasis, and onchocerciasis, commonly known as river blindness. More than 140 million people are affected by these insect-borne parasites in tropical and subtropical countries around the world.

Weil, who joined the School of Medicine faculty in 1982, has conducted research on filariasis for more than 20 years. He was attracted to parasitology research as a medical student in the mid-1970s. At that time, tropical parasitic diseases were among the most formidable unconquered infectious diseases. And the battle continues today.

He also was drawn to the idea of applying recent advances in biology and immunology to these "great neglected diseases," with the hope of developing improved methods for diagnosis, treatment and prevention. "The past 20 years have brought significant progress on the research side, and it is critically important that these efforts continue because there is so much more to learn," Weil said. "But there is a strong trend now to step back from the laboratory and to consider how to apply the new knowledge to control or eliminate tropical diseases."

Weil's research career began during his undergraduate years at Harvard College when he conducted anthropology research for three summers in the Canadian subarctic. He credits two key mentors from that time, an archaeology graduate student and a medical anthropologist, for "infecting" him with the research bug. After receiving a medical degree from Harvard in 1975, he completed a residency in internal medicine at Yale, research training at the National Institutes of Health and a fellowship in infectious diseases at Washington University.

Here, Weil's early research on filariasis focused on the development and testing of improved diagnostic tests. His first independent project in St. Louis was the development of improved methods for diagnosing dog filariasis, or heartworms, based on detection of parasite excretion products in the blood of infected dogs. The work led to an important patent and to tests that veterinarians now use to diagnose heartworm infections. Using methods developed during that project, he later created similar diagnostic tests for human filariasis and onchocerciasis.

Detecting 'worm antigens'

The test is an important advance, said Thomas B. Nutman, M.D., head of the Helminth Immunology Section of the Laboratory of Parasitic Diseases at the National Institutes of Health. "It has enabled detailed parasitological and epidemiologic assessment of filarial-endemic populations," he said. "Moreover, the application of this assay has altered the approach to therapy and control of lymphatic filariasis."

The test fits in well with a new WHO strategy for global elimination of filariasis, Weil said. "Instead of programs based on mass testing for diagnosis of infections and selective treatment of only those with positive tests, the new strategy is based on selective diagnosis and mass treatment."

Weil takes a blood sample from a woman in Egypt during one of some 30 visits he's made there in the last 10 years.

Enough testing is done to establish whether filariasis is present in an area, and those infected are offered repeated annual mass treatments with new two-drug combinations that sterilize the worms for at least one year. Several years of repeated annual treatments should interrupt transmission to the point that residual infections die out and the disease is eliminated.

Current research in Weil's laboratory focuses on immunity to filariasis. Its involves collaborative projects in Egypt with Ain Shams University in Cairo and molecular biology/vaccine research at the medical school. Weil has made some 30 visits to Egypt over the past 10 years.

Weil's laboratory recently opened an insectary for maintaining filarial parasites in mosquitoes. It provides the researchers access to the infecting stage of the parasite, believed to contain some of the key targets of protective immune responses in animals and humans.

Daniel E. Goldberg, M.D., professor of medicine, noted that though Weil's primary activity is research, he is an excellent clinician as well.

Weil, who shares clinical duties with others in the Infectious Diseases Division, would like to see the medical school more involved in global health issues and is working toward improving international education opportunities for medical students.

Humility and realism

Weil lives with his wife, Janice, in Creve Coeur. They enjoy traveling and hiking. She is a veteran school librarian who now volunteers as a teacher at the Butterfly House at Faust Park. They have two college-aged children: Madeleine, majoring in American studies and environmental policy, and Andrew, who is studying anthropology.

Attracted to a career in medical research by youthful idealism and a desire to make a difference, Weil said that after years of toil in the tropical disease trenches he mostly has traded naive optimism for humility and realism. In the fight against tropical diseases, it is unusual for basic research findings to translate directly into a groundbreaking application such as the filariasis test, and he is extremely gratified that some of his research projects have worked out this way. Proud of his group's work, he presses on with his research efforts, taking comfort, he said, in knowing that "today's basic research observations contribute pieces that one day will be assembled as solutions to complex puzzles."