Swimmer’s itch, or cercarial dermatitis, is a short-term, immune reaction occurring in the skin of humans that have been infected by water-borne trematode parasites. Symptoms, which include itchy, raised papules, commonly occur within hours of infection and do not generally last more than a week. The following codes are used with International Statistical Classification of Diseases and Related Health Problems. ... The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. ... Dermatitis is a term literally meaning inflammation of the skin. It is usually used to refer to eczema, which is also known as Dermatitis eczema. ... Diagram of the layers of human skin In zootomy and dermatology, skin is an organ of the integumentary system made up of a layer of tissues that protect underlying muscles and organs. ... Orders not necessarily a complete list Azygiida Echinostomida Opisthorchiida Plagiorchiida Strigeata Strigeatida Trematodes are also known as flukes. ... A parasite is an organism that lives in or on the living tissue of a host organism at the expense of it. ... A papule is a small, solid and usually conical elevation of the skin. ...

The trematodes that cause swimmer’s itch are schistosomes that parasitize snails and birds, particularly waterfowl (one exception is Schistosomatium douthitti, which infects snails and rodents). These groups are not to be confused with schistosomes of the genus Schistosoma, which infect humans and cause the serious human disease schistosomiasis, or with larval stages of Linuche unguiculata, thimble jellyfish, which give rise to seabather's eruption. Two examples of schistosome genera that infect birds but can accidentally infect humans, giving rise to swimmer’s itch, are Trichobilharzia and Gigantobilharzia. Avian schistosomes such as these cannot complete their life cycles in humans. The itchy papules are caused by localized inflammatory immune reactions, each bump corresponding to the penetration site of a single parasite, which dies within hours. Schistosomatidae is a family of digenetic trematodes with complex parasitic life cycles. ... Giant African Snail (Achatina fulica) The name snail applies to most members of the molluscan Class Gastropoda that have coiled shells. ... For other meanings of bird, see bird (disambiguation). ... Falcated Duck at Slimbridge Wildfowl and Wetlands centre, Gloucestershire, England Wildfowl or waterfowl, also waterbirds, is the collective term for the approximately 147 species of swans, geese and ducks, classified in the order Anseriformes, family Anatidae. ... Families See Classification Section The order Rodentia is the most numerous of all the branches on the mammal family tree. ... A genus of trematodes, Schistosoma spp. ... A disease is an abnormal condition of the body or mind that causes discomfort, dysfunction, or distress to the person afflicted or those in contact with the person. ... Skin vesicles created by the penetration of Schistosoma. ... Seabathers Eruption (locally known as sea lice) is an immune response to the larval stage of the thimble jellyfish. ... Parasite life cycles can take a variety of forms, all involving the exploitation of one more hosts. ... Parasite life cycles can take a variety of forms, all involving the exploitation of one more hosts. ... A request has been made on Wikipedia for this article to be deleted in accordance with the deletion policy. ...

Life cycles of non-human schistosomes

Adult stages of avian schistosomes are found in the gastrointestinal tract of the bird host. The worm releases eggs that are shed in the bird’s feces. Upon immersion in water, a short-lived, non-feeding, free-living stage known as the miracidium emerges. The miracidium swims using cilia, following chemical and physical cues that increase its chances of finding the first host in its life cycle, a snail. After infecting a snail it develops into a sporocyst, which in turn undergoes asexual reproduction, yielding large numbers of another short-lived, free-living stage, the cercaria. Cercariae use a tail-like appendage (often forked in genera causing swimmer’s itch) to swim to the surface of the water, as well as other physical and chemical cues, in order to locate the next and final host in the life cycle, a bird. After infecting a bird, the parasite develops into a schistosomulum and eventually migrates to the gastrointestinal tract where it matures and, if it encounters a mate, sheds eggs to begin the cycle anew. The gastrointestinal tract or digestive tract, also referred to as the GI tract or the alimentary canal or the gut, is the system of organs within multicellular animals which takes in food, digests it to extract energy and nutrients, and expels the remaining waste. ... Orders Many - see section below. ... Rabbit feces are usually 8-10 mm in diameter and dry to the touch. ... A girl in a swimming pool Water (from the Old English waeter; c. ... The miracidium is the free swimming larva of some Trematoda including the Schistosoma. ... This article is about an organelle. ... The miracidium is the small free-swimming larva of some Trematoda including the Schistosoma. ... Asexual reproduction in liverworts: a caducuous phylloid germinating Asexual reproduction (also known as agamogenesis) is a form of reproduction which does not involve meiosis, gamete formation, or fertilization. ... The miracidium is the small free-swimming larva of some Trematoda including the Schistosoma. ... In biology, a genus (plural genera) is a taxonomic grouping. ...

Risk factors

Humans usually become infected with avian schistosomes after swimming in lakes or other bodies of slow-moving fresh water. Some laboratory evidence indicates snails shed cercariae most intensely in the morning and on sunny days, and exposure to water in these conditions may therefore increase risk. Duration of swimming has been positively correlated with increased risk of infection in epidemiological studies in Europe and North America, and shallow inshore waters -- snail habitat -- undoubtedly harbour higher densities of cercariae than open waters offshore. Onshore winds are thought to cause cercariae to accumulate along shorelines. Studies of infested lakes and outbreaks in Europe and North America have found cases where infection risk appears to be evenly distributed around the margins of water bodies as well as instances where risk increases in endemic swimmer's itch "hotspots". Children may become infected more frequently than adults but this probably reflects their tendency to swim for longer periods inshore, where cercariae also concentrate. Lake Clearwater, Ontario, Canada A lake is a large body of water, usually fresh water, surrounded by land. ... A male Caucasian toddler child A child (plural: children) is a young human. ...

Control measures

Various strategies, targeting either the mollusc or avian hosts of schistomes, have been used by lakeside residents in recreational areas of North America to deal with outbreaks of swimmer's itch. In Michigan, for decades authorities used copper sulphate as a molluscicide to reduce snail host populations and thereby the incidence of swimmer's itch. The results with this agent have been inconclusive, possibly because Classes Caudofoveata Aplacophora Polyplacophora - Chitons Monoplacophora Bivalvia - Bivalves Scaphopoda - Tusk shells Gastropoda - Snails and Slugs Cephalopoda - Squids, Octopuses, etc. ... The word Avian can refer to different things: .. Most commonly it is used referring to the class of animals named birds. Avians are a fantasy race in several fantasy settings. ... Official language(s) None (English, de-facto) Capital Lansing Largest city Detroit Area  - Total   - Width   - Length    - % water  - Latitude  - Longitude Ranked 10th 102,384 sq mi  265,172 km² 239 miles  385 km 491 miles  790 km 41. ... Copper (II) sulfate (CuSO4) is the most common copper salt, made by the action of sulfuric acid on the base copper oxide. ...

• snails become tolerant
• local water chemistry reduces the molluscicide's efficacy
• local currents diffuse it
• adjacent snail populations repopulate a treated area.

More importantly, perhaps, copper sulphate is toxic to more than just molluscs, and the effects of its use on aquatic ecosystems are not well understood. Another method targeting the snail host, mechanical disturbance of snail habitat, has been also tried in some areas of North America, with promising results. Some work in Michigan suggests that administering praziquantel to hatchling waterfowl can reduce local swimmer's itch rates in humans. Work on schistosomiasis showed that water-resistant topical applications of the common insect repellent DEET prevented schistosomes from penetrating the skin of mice. An aquatic ecosystem is an ecosystem that is based in water, whether it is a pond, lake, river, underground water body, estuary or ocean. ... // Chemical Designation 2-(Cyclohexylcarbonyl)-1,2,3,6,7,11b-hexahydro-4H-pyrazino(2,1-alpha)isoquinolin-4-one History Praziquantel was developed in the laboratories (parasitological research) of Bayer AG in Germany (Elberfeld) 30 years ago. ... DEET chemical structure DEET is an insect-repellent chemical (chemical name N,N-diethyl-meta-toluamide or N,N-diethyl-3-methylbenzamide). ...

Public education of risk factors, a good alternative to the above mentioned interventionist strategies, can also reduce human exposure to cercariae.

See also

Dermatitis

Schistosomiasis

Schistosoma

Dermatitis is a term literally meaning inflammation of the skin. It is usually used to refer to eczema, which is also known as Dermatitis eczema. ... Skin vesicles created by the penetration of Schistosoma. ... A genus of trematodes, Schistosoma spp. ...

External links

• CDC
• DermNet NZ
• Links to pictures of swimmer's itch (Hardin MD/Univ of Iowa)