UNIVERSITY PARK, Pa. -- A professor in Penn State's College of Agricultural Sciences who has studied the biology of fish in Central Africa's huge Lake Malawi since 1983 has been awarded a $1.6 million, five-year joint grant from the National Science Foundation and National Institutes of Health to research how fish might be managed to control the secondary snail hosts of human parasites.

Jay Stauffer, professor of ichthyology, is the lead researcher on the project. Other grant recipients are Penn State's Paola Ferreri, associate professor of fisheries management, and Kenneth McKaye, a professor at the Appalachian Environmental Laboratory, University of Maryland System, based in Frostburg, Md.

Stauffer has studied cichlids in Lake Malawi for the past 20 years. Under his guidance, researchers cataloged new species and generated much of the scientific knowledge known about this family of often bright-colored, tropical fishes that are an important food source for Africans and widely available as aquarium specimens in this country.

The funding will allow the research team to look at whether populations of certain cichlids, now diminished by overfishing, can be managed to again control the organisms that cause the disease schistosomiasis. The organisms must live in specific snail species to complete their life cycle and enter human skin through contact in the water. It is hoped that the cichlids can control schistosomiasis by preying on the snails, which have become much more numerous in Lake Malawi as fish numbers have decreased.

In the last two decades, schistosomiasis in humans has reached epidemic proportions in regions bordering Lake Malawi. Schistosomiasis, commonly known as snail fever, occurs in 74 countries and is ranked second only to malaria as a leading cause of human morbidity by a parasitic agent.

Most infected individuals don't die as a result of the disease; however, there is an estimated 16 percent to 18 percent loss of productivity experienced by infected people.

Stauffer, who contracted schistosomiasis himself from the waters of Lake Malawi, has seen the disease run rampant. Transmission rates are now so high that the disease poses a high risk to the 11,000 or so annual visitors to Lake Malawi National Park.

"From 1977 to 1987, our scientists from Penn State and the University of Maryland studied the biology of the cichlid fishes around Nokumba Peninsula in southern Lake Malawi, and none of the team contracted schistosomiasis from swimming and diving," he says. "In 1991, however, five of six divers were infected with schistosomiasis, and I was infected in 1992."

Stauffer says a sustainable approach to schistosomiasis control is urgently needed, especially at lakeshore villages. Potential methods include improved water supply, sanitation, health education, chemotherapy, molluscicides and biological control agents such as fish. It is the latter on which Stauffer and his associates will concentrate.

A few countries, such as Cameroon, Kenya, Sudan, Zaire and Brazil, have tried to use fishes to control snail hosts. Fish have been shown to control schistosome snail hosts in some aquaculture ponds around Malawi.

"New regulations to prevent fishing in the breeding areas of snail-eating fishes is key to controlling the snail hosts," explains Stauffer. "We know that it is possible to limit the harvests of these fishes at certain localities and during the height of breeding seasons by hiring local fishermen to enforce the fishing regulations. Once the regulations are in effect, local management plans can be tested for their effectiveness in interrupting the life cycle of schistosomes by reducing snail populations."

Ideally, Stauffer adds, if such plans prove successful, they can be expanded to appropriate locales in other areas of Lake Malawi. He believes it will take three to five years for early results to be apparent.

"We are suggesting a strict management and control policy for snail-eating fishes," says Stauffer, "since for the first time a decrease in fish abundance has been directly linked to an outbreak of human disease."

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EDITORS: Jay Stauffer can be contacted at 814-863-0645 or e-mail vc5@psu.edu.

Contact: Jeff Mulhollem jjm29@psu.edu 814-863-2719 814-863-9877 fax #243