Schistosomiasis

(Schistosomiasis)

Schistosomiasis is an infection with leeches of the genus Schistosoma, which is transcutaneously acquired in contaminated fresh water when swimming or wading. The pathogens infect the vascular system of the gastrointestinal or genitourinary system. Acute symptoms dermatitis, which some weeks later, fever, chills, nausea, abdominal pain, diarrhea, malaise, and myalgia are followed. The chronic conditions vary depending on the species, but a bloody diarrhea include (z. B. S. mansoni and S. japonicum) or hematuria (z. B. S. haematobium), the diagnosis is determined by the detection of eggs in faeces provided urine or biopsy material. Serological tests may be sensitive and specific, but allow no statement about the worm burden or clinical status. Treatment is with praziquantel.

Flukes are parasitic flat worms which various parts of the body of infecting (eg., Blood vessels, the gastrointestinal tract, lungs, liver), depending on the type ..

Schistosomiasis is an infection with leeches of the genus Schistosoma, which is transcutaneously acquired in contaminated fresh water when swimming or wading. The pathogens infect the vascular system of the gastrointestinal or genitourinary system. Acute symptoms dermatitis, which some weeks later, fever, chills, nausea, abdominal pain, diarrhea, malaise, and myalgia are followed. The chronic conditions vary depending on the species, but a bloody diarrhea include (z. B. S. mansoni and S. japonicum) or hematuria (z. B. S. haematobium), the diagnosis is determined by the detection of eggs in faeces provided urine or biopsy material. Serological tests may be sensitive and specific, but allow no statement about the worm burden or clinical status. Treatment is with praziquantel. Flukes are parasitic flat worms which various parts of the body of infecting (eg., Blood vessels, the gastrointestinal tract, lungs, liver), depending on the type .. The etiology Schistosomiasis is by far the most important Trematodeninfektion. Schistosoma is the only trematode which can penetrate the skin; all other trematodes infect only by ingestion. about 200 million people worldwide are infected. Five Schistosomenarten infect humans, all of which have a similar life cycle of freshwater snails involved. S. haematobium causes urinary tract and the other Schistosoma sp cause intestinal illness. The geographical distribution is distinguished by species: S. haematobium: Widely used on the African continent, smaller flock there in the Middle East, Turkey and India S. mansoni: widespread in Africa, flock in the Middle East and the only species the Western hemisphere in parts of South America and some Caribbean islands of S. japonicum: Asia, especially in China, the Philippines, Thailand and Indonesia S. mekongi: Southeast Asia S. intercalatum: Central and West Africa man is the main reservoir of infection. Dogs, cats, rodents, pigs, horses and goats are reservoirs for S. japonicum, and dogs are reservoirs for S. mekongi. The disease can be imported travelers and immigrants from endemic areas with a transfer takes place within the US and Canada but not held. Pathophysiology adults live worms and reproduce sexually in the small veins of the mesentery (typically S. japonicum and S. mansoni) or bladder (typically S. haematobium- Simplified life cycle of Schistosoma.). Some eggs penetrate the intestinal or Harnblasenmukosa and are excreted in the stool or urine; others remain in the host organ or transported via the portal vein to the liver and, occasionally, to other locations (eg. B. lung, CNS, spinal cord). The separated eggs hatch in fresh water and put miracidia (first instar) free infested snails. After a growth phase of thousands of free-floating cercariae are released. Cercariae penetrate within minutes of exposure to human skin, and are converted into Schistosomulae which are transported with the bloodstream to the liver where they mature into adults. The adults then migrate to their final location in the intestinal veins or the venous plexus of the urogenital tract. The eggs appear 1-3 months after Zerkarienpenetration in the stool or urine. It is estimated that adult worms can live 3-7 years. The females are of the order of 7-20 mm; Males are slightly smaller. Simplified life cycle of Schistosoma. In the human host are eggs that contain miracidia with feces or urine excreted into the water. In water, the eggs hatch and set miracidia free. The miracidia swim and penetrate a snail (intermediate host). In the snail, the miracidia develop through two generations of sporocysts to cercariae. The free-swimming cercariae are released from the snail and penetrate the skin of the human host. During the penetration, the cercariae lose their forked tail and become schistosomes. The schistosomes are transported through the vascular system to the liver. There they mature into adult animals. The paired (male and female) adult worms migrate to place (depending on species) to the intestinal vein in the intestine or rectum or the venous plexus of the urogenital tract, where they remain and begin eggs. Symptoms and signs Acute Schistosomendermatitis Most infections are asymptomatic. An itchy rash (Cercariendermatitis) may develop where the cercariae in sensitized people to the skin eindringen.Akutes Katayamafieber Katayamafieber can occur with the onset of egg laying, typically 2-4 weeks after a severe exposure. The symptoms consist of fever, chills, cough, nausea, abdominal pain, malaise, myalgia, urticaria and a marked eosinophilia, reminiscent of a serum sickness. The manifestations are more common among visitors and usually heavier than the native endemic areas and keep characteristically several weeks an.Chronische schistosomiasis Chronic schistosomiasis mostly comes into being as a result of host defense against tissue constant eggs. Still in the early stages can S. mansoni or S. japonicum lead to ulceration of the mucosa, bleeding, or can cause bloody diarrhea. With progression of the lesions focal fibrosis, strictures, fistulas and papillomatous growths can form in the intestine. Granulomatous reactions in the liver contained eggs of S. mansoni and S. japonicum not usually lead to a deterioration of liver functions, but can cause fibrosis and cirrhosis, which can lead to portal hypertension resulting in a Hematemesis by esophageal varices. Eggs in the lungs contained may cause granulomas and focal obliterative arteritis, which ultimately can cause pulmonary hypertension and pulmonary cor. In a S. haematobium infection, Blasenulzerationen can lead to dysuria, hematuria, and urinary frequency. Over time, a chronic cystitis develops. Strictures can lead to Hydroureter and hydronephrosis. Papillary growths in the bladder are common, and it can develop a transitional cell carcinoma. Because of blood loss from both the gastrointestinal and from the urogenital tract often leads to anemia. Also frequently often leads to a secondary bacterial infection of the urogenital tract. Also, a persistent Salmonellenseptikämie by infection of schistosomes (Schistosoma mansoni) with salmonella and thus an escape option opposite the antibiotic treatment can occur. Several species, especially S. haematobium, can cause genital diseases that lead to a variety of symptoms including. Infertility in both men and women. Neurological complications can occur even with light Schistosoma infections. Eggs in the spinal cord located or adult worms may result in a transverse myelitis and those in the brain can cause focal lesions and ictus. Diagnosis Microscopic examination of stool or urine (S. haematobium) Serological tests on eggs, the chair or the urine (S. haematobium and occasionally S. japonicum) is examined for eggs. It may be necessary repeated examinations incl. Enrichment techniques. Since the geography for species identification plays an important role, exposure history should be reported to the laboratory. If the clinical picture speaks for schistosomiasis, but also after repeated testing of urine or feces or eggs can be detected, a biopsy of the colon or Harnblasenmukosa can be performed to detect the eggs. Depending on the used antigens, serological tests can be highly sensitive and specific for detecting an infection, but allow no statement about the worm burden, the clinical status or prognosis. Treatment praziquantel is a one-day oral therapy with praziquantel (20 mg / kg 2 times a day in S. haematobium, S. mansoni and S. intercalatum; kg 3 times a day for S. japonicum and S. mekongi 20 mg /) recommend , Praziquantel is effective against adult present schistosome, but not against developing schistosomula, early in infection. Thus, the treatment for 6 to 8 weeks after the last exposure is delayed for travelers. Side effects of praziquantel are usually mild and include abdominal pain, diarrhea, headache and dizziness. About treatment failure was reported, but it is difficult to judge whether this is due to re-infection or drug-resistant strains. If eggs are present at the time of diagnosis, follow-up testing 1 to 2 months after treatment is advisable to confirm the healing. The treatment is repeated when eggs are still present. Treatment of Katayamafiebers is unclear. Praziquantel is early during infection not particularly effective; Corticosteroids may relieve severe symptoms. Patients should be tested for living worm eggs 3 and 6 months after therapy. A repeat of the therapy is required if the egg excretion is not significantly decreased. Prevention To avoid infection, contact with contaminated fresh water should be scrupulously avoided. Fresh water for bathing should be boiled for at least 1 minute and then cooled before bathing. However, should water that has been stored for at least 1 to 2 days in a storage tank, be sure without cooking. Persons who are accidentally exposed to potentially contaminated water (eg. As by falling into a river) should dry off with a towel intensively to try to remove any parasites before they penetrate the skin. The hygienically correct disposal of urine and stool reduces the likelihood of infection. Adult residents of endemic areas are more resistant than children, which suggests the possibility of an acquired immunity to reinfection. A vaccine is currently in development. Important points Schistosoma is the only trematode that penetrates through the skin; about 200 mil. People are infected worldwide. The cercariae mature in the liver and the adult animals then migrate to their final location in the intestinal veins or the venous plexus of the urogenital tract. The organisms in the liver causing a granulomatous reaction that can lead to fibrosis and cirrhosis. The organisms in the intestines can cause bloody diarrhea and organisms in the bladder can cause hematuria and chronic cystitis. Treatment is with praziquantel. To prevent infection, contact with fresh water in endemic regions is avoided. caused by avian and other animal schistosome dermatitis (Cercaria Dermatitis clam diggers itch; swimmers-itch) Cercaria Dermatitis, a skin condition that occurs when Schistosoma sp that can not develop in people, during contact with contaminated freshwater or brackish water into the skin penetration. Cercariae of Schistosoma sp., Which infect birds and non-human mammals can penetrate the skin. Although the pathogens in humans do not develop, people are sensitized and thereby develop at the penetration site itchy maculopapular, then vesicular skin lesions. The skin lesions may be accompanied by systemic febrile reaction, which lasts for 5-7 days and dissolves spontaneously. Cercaria Dermatitis occurs worldwide. In North America, a marine-related saltwater Schistosomendermatitis comes (Clam Digger-itch) before on all coasts of the Atlantic, the Gulf of Mexico, the Pacific and the Hawaiian Islands. Often this occurs in the murky flat waters off Cape Cod. In the region of the “Great Lakes” there is often a freshwater Schistosomendermatitis (float-itch). (N. D. Übers .: Even lakes in Central Europe may contain avian schistosomes.) The diagnosis of Cercaria Dermatitis is based on clinical criteria. In most cases, medical treatment is not necessary. The treatment of Cercaria Dermatitis done with Kühlkompressen, baking soda or antipruritic ointments. Topical corticosteroids may also be used.