Schistosomia.ppt salem f gerbadi pathio 848

Schistosomia.ppt salem f gerbadi pathio 848

• 1.
  Schistosomiasis
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  Schistosomiasis (also knownas bilharzia, bilharziosis or snail fever) is a chronic parasitic disease caused by several species of flatworm of the genus Schistosoma Schistosoma and can cause liver, intestinal and urinary damage.  It is most commonly found in Asia, Africa, and South America, especially in areas with water that is contaminated with freshwater snails, which may carry the parasite.
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  Types There are fivespecies of flatworms that cause schistosomiasis. • Schistosoma mansoni and Schistosoma Intercalatum cause ((intestinal)) schistosomiasis • Schistosoma haematobium causes ((urinary)) schistosomiasis  Each causes a different clinical presentation of the disease.
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  Epidemiology  The definitivevertebrate host is man.  The «intermediate» invertebrate host are the snails snails (usually of the Biomphalaria, Bulinus,  The mechanism of transfer is contact with contaminated water contaminated water.  The reservoir hosts for the S. japonicum are cattle, water cattle, water buffalo, pigs, dogs, and rodents buffalo, pigs, dogs, and rodents serve as major reservoirs;  For the S. mansoni are possible but less important non-human primates and some rodents can sometimes act as reservoirs.  Adult worms live for 3 to 7 years on average (in an endemic area up to 30 years previously), during which time the female worm produces eggs at the rate of 300 a day (S. mansoni) to 3000 a day (S. japonicum).
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  Schistosoma mansoni -is cause of intestinal schistosomiasis Morphology
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  Geographical distribution • Schistosomamansoni is found in parts of South America and the Caribbean, Africa, and the Middle East;
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  Schistosoma haematobium causes urinaryschistosomiasis Morphology
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  Geographical distribution • S.haematobium is found in Africa and the Middle East;
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  Schistosoma japonicum causes asianintestinal schistosomiasis Morphology
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  Geographical distribution • S.japonicum is found in the Far East
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  Life cycle
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  Clinical features • Aboveall, schistosomiasis is a chronic disease. Many infections are subclinically symptomatic, with mild anemia and malnutrition being common in endemic areas. Acute schistosomiasis (Katayama's fever) may occur weeks after the initial infection, especially by S. mansoni and S. japonicum. Manifestations include: • Abdominal pain • Cough • Diarrhea • Eosinophilia - extremely high eosinophil granulocyte count. • Fever • Fatigue • Hepatosplenomegaly - the enlargement of both the liver and the spleen.
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  Clinical features There are4 stages 1. STAGE OF INVASION: Cercarial Dermatitis 2. STAGE OF MATURATION: Acute Schistosomiasis 3. STAGE OF ESTABLISHED INFECTION 4. STAGE OF LATE INFECTION AND SEQUELAE
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  STAGE OF INVASION:CERCARIAL DERMATITIS • Penetration of the skin by cercariae, leads to occurrence of dermatitis (cercarial dermatitis or «swimmer's itch») and can be associated the death of cercariae in the skin. • A transient immediate hypersensitivity reaction that occurs 10 to 15 min after exposure is followed by a more prolonged, delayed reaction, which develops after 12 to 24 h and may persist for up to 15 days. • The lesion is characterized by a small, red, pruritic, macular rash, which progresses to papules, possibly accompanied by vesicle formation and oedema. Pustules may form if secondary infection occurs, and residual pigmentation may persist for months. • The next symptoms develops a few days after exposure and can be associated with transient fever, cough and pulmonary infiltrates, as well as myalgia and abdominal pain.
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  STAGE OF MATURATION:ACUTE SCHISTOSOMIASIS  fever, (intermittent or remittent with fever, (intermittent or remittent with evening peaks) evening peaks)  Rigors, Rigors,  sweating, sweating,  headache, headache,  malaise, malaise,  muscular aches, muscular aches,  profound weakness, profound weakness,  an unproductive, irritating cough, an unproductive, irritating cough,  abdominal pain or swelling, abdominal pain or swelling,  nausea, vomiting, nausea, vomiting,  diarrhoea, and loss of weight. diarrhoea, and loss of weight.  oedema, oedema,  a generalized soft lymphadenopathy, a generalized soft lymphadenopathy,  a tender enlarged liver, enlarged and a tender enlarged liver, enlarged and soft spleen, stuporose, or show visual soft spleen, stuporose, or show visual impairment or papilloedema. impairment or papilloedema.  Severe central-nervous manifestations Severe central-nervous manifestations  Eggs become detectable in the faeces Eggs become detectable in the faeces about 6 weeks after exposure about 6 weeks after exposure.
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  STAGE OF ESTABLISHED INFECTION S.haematobium infection: • Hypogastric Discomfort, Hypogastric Discomfort, • Suprapubic Pain, Suprapubic Pain, • Dysuria, Dysuria, • Haematuria, Proteinuria And Haematuria, Proteinuria And Pyuria. Pyuria. S. mansoni and S. japonicum infections is very frequently asymptomatic. Classical symptoms include: Classical symptoms include: • hypogastric pain, hypogastric pain, • diarrhoea, and the diarrhoea, and the • passage of blood or mucus in passage of blood or mucus in the stool. the stool. • the liver may be enlarged and the liver may be enlarged and tender; tender; • the spleen may also be the spleen may also be enlarged, but is usually soft. enlarged, but is usually soft.
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  STAGE OF LATEINFECTION AND SEQUELAE Urinary Schistosomiasis Urinary Schistosomiasis In The Bladder: In The Bladder: • Calcification, Calcification, • Ulceration, Ulceration, • Papillomas, Papillomas, • Nocturia, Nocturia, • Retention Of Urine, Retention Of Urine, • Dribbling, Dribbling, • Severe Pain. Severe Pain. • The Ureteric Pathology Is Usually The Ureteric Pathology Is Usually Asymptomatic, But May Lead To Asymptomatic, But May Lead To Ureteric Colic. Ureteric Colic. • Uraemia. Uraemia. S. mansoni and S. japonicum S. mansoni and S. japonicum infections infections, is associated with: • intermittent diarrhoea, with or intermittent diarrhoea, with or without the passage of blood or without the passage of blood or mucus; mucus; • the colon may be tender. the colon may be tender. • In between the episodes of In between the episodes of diarrhoea, the stools are normal. diarrhoea, the stools are normal. • bleeding from oesophageal bleeding from oesophageal varices varices • haematemesis, haematemesis, • melaena. melaena. • Blood loss is frequently Blood loss is frequently massive, and exsanguination is massive, and exsanguination is the usual cause of death rather the usual cause of death rather than hepatic coma. than hepatic coma.
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  Laboratory diagnosis • Microscopicexam Microscopic exam: : detection the detection the eggs in the eggs in the feces o feces or urine r urine. . • Pelvic x-ray Pelvic x-ray. . • Photomicrography of Photomicrography of bladder in S. bladder in S. hematobium infection, hematobium infection, showing clusters of the showing clusters of the parasite eggs with parasite eggs with intense eosinophilia intense eosinophilia
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  Laboratory diagnosis • Tissuebiopsy (rectal biopsy and biopsy of the bladder) may demonstrate eggs when stool or urine examinations are negative. • Serology test – Antibody detection.
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  Treatment  Praziquantel -is safe and highly effective in curing an infected patient, it does not prevent re- infection by cercariae and is thus not an optimum treatment for people living in endemic areas. Praziquantel is universally used.  Antimony  Oxamniquine  Niridazole,  Metrifonate •
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  Preventation • Individual protectionagainst infection is Individual protection against infection is achieved by avoiding contact with all achieved by avoiding contact with all potentially contaminated fresh water in potentially contaminated fresh water in endemic areas; for example, by wearing endemic areas; for example, by wearing boots and other waterproof clothing. boots and other waterproof clothing. • Such water should be boiled before Such water should be boiled before drinking, or left to stand for at least 2 drinking, or left to stand for at least 2 days before use for other purposes such days before use for other purposes such as washing. Should contact with water as washing. Should contact with water occur, the skin should be immediately occur, the skin should be immediately rubbed vigorously with a towel; the water rubbed vigorously with a towel; the water should not be allowed to evaporate, as should not be allowed to evaporate, as this aids cercarial penetration. this aids cercarial penetration. • Soap and alcohol also kill cercariae, and Soap and alcohol also kill cercariae, and cercaricidal barrier creams can be used. cercaricidal barrier creams can be used.