BUFFALO, N.Y. -- Researchers at the state university here areworking jointly with three universities in Egypt to develop arecombinant vaccine against schistosomiasis, a potentially fatalparasitic disease that is a major health problem in much of thelesser-developed world.
Several candidates for a subunit vaccine are being tested inrats in studies under way at the State University of New Yorkat Buffalo, according to Philip T. LoVerde, a SUNYABmicrobiology professor and principal investigator on theproject.
"The final vaccine will probably be a cocktail of severalantigens," LoVerde said.
The collaboration is being funded by the U.S. Agency forInternational Development (AID) and the Egyptian Ministry ofHealth, which together have provided $600,000 so far.LoVerde's laboratories, like other U.S. researchers working onschistosomiasis, has received grants from the NationalInstitutes of Health.
Other university-based teams working on vaccines and otherschistosomiasis research are at Johns Hopkins, Harvard and theUniversity of California, San Francisco. Several Europeanlaboratories are also active, including Institut Pasteur nearParis, which is planning the equivalent of a Phase I humanclinical trial of its own vaccine.
Some vaccine candidates that have performed well in testsusing rats have not provoked the same level of response intests involving larger mammals, LoVerde said.
Schistosomiasis annually kills an estimated 800,000 people,many of them children. The problem is particularly severe inEgypt, where an estimated 20 percent to 33 percent of thenation's 55 million people are infected. A few cases of thedisease were diagnosed last year among U.S. troops serving inDesert Storm.
Humans are typically infected through contact withcontaminated water in streams or irrigation canals, wherelarvae have the enzymes to break through skin. The parasitedevelops into an adult worm of up to three-quarters of an inchin length in the bloodstream. The initial infection is usuallymarked by nothing more than a mild rash, but produces inabout 45 days symptoms of nausea, body aches and diarrhea.Chronic cases are marked by extreme fatigue and an enlargedliver and spleen. Schistosomiasis has also been associated withbladder cancer.
The sole effective drug treatment for the disease ispraziquantel, which has few side effects, LoVerde said.However, schistosomiasis has a history of developing strainsthat are resistant to other drugs.
SUNYAB is the only U.S. university that is working on a vaccine,as part of a $39 million, multiyear project sponsored by AID tocombat the disease. No patents have been sought and there hasbeen no commercial interest in a potential product so far,LoVerde said.
-- Ray Potter Senior Editor
(c) 1997 American Health Consultants. All rights reserved.