USF Prof. John T. Sullivan believes a snail's immune system holds the secret to protecting people from schistosomiasis, which infected about 240 million in 2011.
University of San Francisco biology Professor John T. Sullivan sees the struggle between man and nature when he peers through his microscope at a freshwater snail, the kind that sickened at least 240 million people in 78 countries in 2011, according to the World Health Organization (WHO). But the same snails that carry and spread the illness might also hold the secret to stopping it, and they offer one tantalizing clue that could change everything.
The sickness, schistosomiasis, is caused by a tiny parasite that makes its home in the snail. The wormlike predator infects its human host by boring through their skin, causing rashes, fevers, intestinal bleeding, and in severe cases, bladder cancer and kidney or liver failure. The disease is transmitted when people come in contact with water where the snails live, like the rivers and lakes in developing countries that many use for swimming or bathing. It is treatable, but many victims live far from a clinic and have no money for medicine.
"Worldwide, only malaria is more socio-economically devastating than schistosomiasis," said Sullivan, who has studied the illness since 1972. "It is a disease that wreaks havoc on entire towns and villages. Yet relatively few resources are put to understanding and stopping it."
There's one thing about the snails, one simple thing that so intrigues Sullivan that his research focuses on it: some snails don't carry the parasite. If Sullivan can unlock the genetic secret behind why some snails are immune and others are not, he might be able to develop a family of snails that is parasite-free and use it to stop, or at least curb, transmission of the disease.
"Developing a resistant line of snails would give us the option of replacing the native susceptible snails, thereby blocking the disease's transmission," Sullivan said. "Short of a vaccine, which parasitologists have worked on unsuccessfully for years, this might be the best chance to help those who suffer needlessly from this dire, chronic disease."
Sullivan's research has been supported by grants totaling more than $1.8 million from organizations like the National Science Foundation, the WHO, and the U.S. Department of Energy. The latest is a grant from the National Institutes of Health worth more than $260,000.