Schistosomiasis Vaccine

A Schistosomiasis vaccine is a vaccine against Schistosomiasis (also known as bilharzia, bilharziosis or snail fever), a parasitic disease caused by several species of fluke of the genus Schistosoma. No effective vaccine for the disease exists yet. Schistosomiasis affects over 200 million people worldwide, mainly in rural agricultural and peri-urban areas of developing countries, and approximately 10% suffer severe health complications from the infection. While chemotherepeutic drugs, such as praziquantel, oxamniquine and metrifonate, are currently considered safe and effective for the treatment of schistosomiasis, reinfection occurs frequently following drug treatment, thus a vaccine is sought to provide long-term treatment. Several studies have determined that an age-dependent resistance to reinfection after cure of schistosomiasis through chemotherapeutic treatment occurs in some patients, suggesting that immunity to Schistosoma infection can be acquired and vaccination may be an effective treatment option. Additionally, experimental vaccination efforts have been successful in animal models of schistosomiasis.

Paramyosin has been proposed as a vaccine candidate.

At present Sm-p80 (calpain) is the sole schistosome vaccine candidate that has been tested for its prophylactic and antifecundity efficacy in different vaccine formulations and approaches (e.g., DNA alone, recombinant protein and prime boost) in two very different experimental animal models (mouse and baboon) of infection and disease. Sm-p80-based vaccine formulation(s) have four effects: Reduction in adult worm numbers; Reduction in egg production (complete elimination of egg induced pathology both in baboons and mice); Protection against acute schistosomiasis; Therapeutic effect on adult worms. This vaccine is now now ready for human clinical trials.

Another target is Sm14.