A Schistosomiasis vaccine is a vaccine against Schistosomiasis (also known as bilharzia, bilharziosis or snail fever), a

parasitic disease A parasitic disease, also known as parasitosis, is an infectious disease caused by parasites. Parasites are organisms which derive sustenance from its host while causing it harm. The study of parasites and parasitic diseases is known as parasitolo ...

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 the

third world The term "Third World" arose during the Cold War to define countries that remained non-aligned with either NATO or the Warsaw Pact. The United States, Canada, Japan, South Korea, Western European nations and their allies represented the " First ...

, and approximately 10% suffer severe health complications from the infection. While chemotherapeutic drugs, such as

praziquantel Praziquantel (PZQ), sold under the brandname Biltricide among others, is a medication used to treat a number of types of parasitic worm infections in mammals, birds, amphibians, reptiles, and fish. In humans specifically, it is used to treat sc ...

, oxamniquine and

metrifonate Metrifonate (INN) or trichlorfon (USAN) is an irreversible organophosphate acetylcholinesterase inhibitor. It is a prodrug which is activated non-enzymatically into the active agent dichlorvos. It is used as an insecticide. According to the US ...

both no longer on the market, 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. Additionally, experimental vaccination efforts have been successful in

animal model An animal model (short for animal disease model) is a living, non-human, often genetic-engineered animal used during the research and investigation of human disease, for the purpose of better understanding the disease process without the risk of ha ...

s 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 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 ready for human clinical trials. Another target is Sm14.

Research support

Schistosomiasis has been considered a "

neglected disease Neglected tropical diseases (NTDs) are a diverse group of tropical infections that are common in low-income populations in developing regions of Africa, Asia, and the Americas. They are caused by a variety of pathogens, such as viruses, bacter ...

" that disproportionately affects poorer localities and has received little attention from

pharmaceutical companies The pharmaceutical industry discovers, develops, produces, and markets drugs or pharmaceutical drugs for use as medications to be administered to patients (or self-administered), with the aim to cure them, vaccinate them, or alleviate symptoms. ...

. Support for current research efforts to develop hookworm vaccines has come from the Schistosomiasis Vaccine Initiative, a program of the Sabin Vaccine Institute in collaboration with

George Washington University The George Washington University (GW or GWU) is a Private university, private University charter#Federal, federally chartered research university in Washington, D.C. Chartered in 1821 by the United States Congress, GWU is the largest Higher educat ...

, the

Oswaldo Cruz Foundation The Oswaldo Cruz Foundation (Portuguese ''Fundação Oswaldo Cruz'', also known as FIOCRUZ) is a scientific institution for research and development in biological sciences located in Rio de Janeiro, Brazil; it is considered one of the world's ma ...

, the Chinese Institute of Parasitic Diseases, the

Queensland Institute of Medical Research The QIMR Berghofer Medical Research Institute (QIMR Berghofer) is an Australian medical research institute located in , Brisbane, in the state of Queensland. QIMR was established in 1945 by the Government of Queensland through the enactment of ...

, and the

London School of Hygiene and Tropical Medicine The London School of Hygiene and Tropical Medicine (LSHTM) is a public research university in Bloomsbury, central London, and a member institution of the University of London that specialises in public health and tropical medicine. The inst ...

.Schistosomiasis Overview
Sabin Vaccine Institute

References

External links

* {{Vaccines Vaccines