Schistosomiasis, also known as snail fever, bilharzia, and Katayama fever, is a disease caused by parasitic flatworms called schistosomes. The urinary tract or the intestines may be infected. Symptoms include abdominal pain, diarrhea, bloody stool, or blood in the urine. Those who have been infected for a long time may experience liver damage, kidney failure, infertility, or bladder cancer. In children, it may cause poor growth and learning difficulty.
Trematoda is a class of flatworms known as flukes or trematodes. They are obligate internal parasites with a complex life cycle requiring at least two hosts. The intermediate host, in which asexual reproduction occurs, is usually a snail. The definitive host, where the flukes sexually reproduce, is a vertebrate. Infection by trematodes can cause disease in all five traditional vertebrate classes: mammals, birds, amphibians, reptiles, and fish.
Schistosoma is a genus of trematodes, commonly known as blood flukes. They are parasitic flatworms responsible for a highly significant group of infections in humans termed schistosomiasis, which is considered by the World Health Organization as the second-most socioeconomically devastating parasitic disease, with hundreds of millions infected worldwide.
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 schistosomiasis, clonorchiasis, opisthorchiasis, tapeworm infections, cysticercosis, echinococcosis, paragonimiasis, fasciolopsiasis, and fasciolosis. It should not be used for worm infections of the eye. It is taken by mouth.
Clonorchiasis is an infectious disease caused by the Chinese liver fluke and two related species. Clonorchiasis is a known risk factor for the development of cholangiocarcinoma, a neoplasm of the biliary system.
Trematodes are parasitic flatworms of the class Trematoda, specifically parasitic flukes with two suckers: one ventral and the other oral. Trematodes are covered by a tegument, that protects the organism from the environment by providing secretory and absorptive functions.
Schistosoma japonicum is an important parasite and one of the major infectious agents of schistosomiasis. This parasite has a very wide host range, infecting at least 31 species of wild mammals, including 9 carnivores, 16 rodents, one primate (human), two insectivores and three artiodactyls and therefore it can be considered a true zoonosis. Travelers should be well-aware of where this parasite might be a problem and how to prevent the infection. S. japonicum occurs in the Far East, such as China, the Philippines, Indonesia and Southeast Asia.
Schistosoma mansoni is a water-borne parasite of humans, and belongs to the group of blood flukes (Schistosoma). The adult lives in the blood vessels near the human intestine. It causes intestinal schistosomiasis. Clinical symptoms are caused by the eggs. As the leading cause of schistosomiasis in the world, it is the most prevalent parasite in humans. It is classified as a neglected tropical disease. As of 2021, the World Health Organization reports that 251.4 million people have schistosomiasis and most of it is due to S. mansoni. It is found in Africa, the Middle East, the Caribbean, Brazil, Venezuela and Suriname.
Swimmer's itch, cercarial dermatitis or schistosome dermatitis is a short-term allergic contact dermatitis occurring in the skin of humans that have been infected by water-borne schistosomes, a type of flatworm. It is common in freshwater, brackish and marine habitats worldwide. The incidence of this condition may be increasing, although this may be attributed to better monitoring and reporting. Nevertheless, the condition is considered to be an emerging infectious disease.
Schistosoma intercalatum is a parasitic worm found in parts of western and central Africa. There are two strains: the Lower Guinea strain and the Zaire strain. S. intercalatum is one of the major agents of the rectal form of schistosomiasis, also called bilharzia. It is a trematode, and being part of the genus Schistosoma, it is commonly referred to as a blood-fluke since the adult resides in blood vessels.
Schistosoma haematobium is a species of digenetic trematode, belonging to a group (genus) of blood flukes (Schistosoma). It is found in Africa and the Middle East. It is the major agent of schistosomiasis, the most prevalent parasitic infection in humans. It is the only blood fluke that infects the urinary tract, causing urinary schistosomiasis, and is the leading cause of bladder cancer. The diseases are caused by the eggs.
Schistosoma malayensis is a schistosome parasite. It was first described in 1988 in Peninsular Malaysia and appears to be a zooenotic infection. The species is named after the country of Malaysia. The natural vertebrate host is van Müller's rat. The intermediate hosts are aquatic snails, Robertsiella kaporenisis. Among Robertsiella kaporenisis are two other Roberstiella species.
Schistosoma nasale is a species of digenetic trematode in the family Schistosomatidae. S. nasale inhabits blood vessels of the nasal mucosa and causes "snoring disease" in cattle, but remains symptomless in buffaloes though extruding its eggs in nasal discharge. The first intermediate host is a freshwater snail Indoplanorbis exustus that may be the sole natural intermediate host for Schistosoma nasale on the Indian sub-continent.
A Schistosomiasis vaccine is a vaccine against Schistosomiasis, 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 the third world, and approximately 10% suffer severe health complications from the infection. While chemotherapeutic drugs, such as praziquantel, oxamniquine and metrifonate 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 models of schistosomiasis.
Neotricula aperta is a species of freshwater snail, an aquatic gastropod mollusk in the family Pomatiopsidae.
Schistosoma spindale is a species of digenetic trematode in the family Schistosomatidae. It causes intestinal schistosomiasis in the ruminants.
Bivitellobilharzia nairi is a species of trematodes, part of the family Schistosomatidae. This is a fairly new identified endoparasite that was found in 1955 by Mudaliar and Ramanujachari, who first recorded the parasite in India. Researchers collected fecal samples of the Indian rhinoceros and were startled to find B. nairi eggs.
Schistosoma bovis is a two-host blood fluke, that causes intestinal schistosomiasis in ruminants in North Africa, Mediterranean Europe and the Middle East. S. bovis is mostly transmitted by Bulinus freshwater snail species. It is one of nine haematobium group species and exists in the same geographical areas as Schistosoma haematobium, with which it can hybridise. S. bovis-haematobium hybrids can infect humans, and have been reported in Senegal since 2009, and a 2013 outbreak in Corsica.
Heterobilharzia is a genus of trematodes in the family Schistosomatidae. The species Heterobilharzia Americana is a parasite of the Southeastern United States and typically found in raccoons. Species of this genus are responsible for Schistosoma in canines. Cercariae found in freshwater may also cause Swimmer's itch in humans.
Gastropod-borne parasitic diseases (GPDs) are a group of infectious diseases that require a gastropod species to serve as an intermediate host for a parasitic organism that can infect humans upon ingesting the parasite or coming into contact with contaminated water sources. These diseases can cause a range of symptoms, from mild discomfort to severe, life-threatening conditions, with them being prevalent in many parts of the world, particularly in developing regions. Preventive measures such as proper sanitation and hygiene practices, avoiding contact with infected gastropods and cooking or boiling food properly can help to reduce the risk of these diseases.
