2Sometimes referred to as bilharzias, bilharziasis, or snail fever, is a parasitic disease caused by trematode(flukes) flatworms of the genus Schistosoma.Belong to Phylum Platyhelminthes
3Historyschistosomiasis was discovered by Theodore Bilharz, a German surgeon working in Cairo, who first identified the etiological agent Schistosoma hematobium in 1851The first doctor who described the entire disease cycle was Pirajá da Silva in 1908.It was a common cause of death for Ancient Egyptians in the Greco-Roman Period.
5classification Schistosoma mansoni Schistosoma hematobium Schistosoma japonicumS. intercalatumS. mekongi***Trichobilharzia ocellata (cause swimmers itch)Four species routinely infect the human host, and several others rarely do so.
9EpidemiologyIt is endemic to at least 76 tropical and sub- tropical countries.more than 200 million people are infected worldwide. In terms of impact this disease is second only to malaria as the most devastating parasitic disease. Schistosomiasis is considered one of the Neglected Tropical Diseases (NTDs)
10The disease is found in tropical countries in Africa, the Caribbean, eastern South America, Southeast Asia and in the Middle East.Schistosoma mansoni is found in parts of South America and the Caribbean, Africa, and the Middle East;S. haematobium in Africa and the Middle East; and S. japonicum in the Far East.S. mekongi and S. intercalatum are found locally in Southeast Asia and central West Africa, respectively
13TransmissionRisk Factor- Wading and swimming in fresh water in tropical regionsYou get a schistosoma infection through contact with contaminated water. The parasite in its infective stages is called a cercaria. It swims freely in open bodies of water.
18Schistosomiasis is due to immunologic reactions to Schistosoma eggs trapped in tissues. Antigens released from the egg stimulate a granulomatous reaction involving T cells, macrophages, and eosinophils that results in clinical diseaseInitially, the inflammatory reaction is readily reversible. In the latter stages of the disease, the pathology is associated with collagen deposition and fibrosis, resulting in organ damage that may be only partially reversible.
19Photomicrography of bladder in S. hematobium infection, showing clusters of the parasite eggs with intense eosinophilia
26All snail species susceptible to infection with Schistosoma mansoni and S. haematobium belong to the family Planorbidae in the subclass Pulmonata.Schistosoma mansoni infects snails in the genus Biomphalaria, and these can also become infected with S. mansoni-S. intercalatum hybrids, S. rodhaini and S. eduardiense.Schistosoma haematobium infects pulmonate snails of the genus Bulinus.Oncomelania for S japonicumTricula (Neotricula aperta) for S mekongi
27Clinical Presentation Symptoms and signs depend on the number and location of eggs trapped in the tissues.
28Eggs can end up in the skin, brain, muscle, adrenal glands, and eyes Eggs can end up in the skin, brain, muscle, adrenal glands, and eyes. As the eggs penetrate the urinary system, they can find their way to the female genital region and form granulomas in the uterus, fallopian tube, and ovaries.Central nervous system (CNS) involvement occurs because of embolization of eggs from the portal mesenteric system to the brain and spinal cord via the paravertebral venous plexus.
29location Intestinal Urinary S. mansoni S. japonicum S. intercalatum S. mekongiS. hematobium
31Acute schistosomiasis Katayama syndrome- is a systemic, serum sickness-like illness that develops after several weeks in some, but not most, individuals with new schistosomal infections.is associated with marked peripheral eosinophilia and circulating immune complexesmost common with S japonicum and S mansoni infectionsis most likely to occur in heavily infected individuals after primary infection
32present usually 4-8 weeks after(exposure to S japonicum or S mansoni) contact with infested water Fever, lethargy, malaise, and myalgia are the most common symptomsLess common symptomscough,headache, anorexiarash (urticarial or papular)Right upper quadrant pain and bloody diarrhea may also occurpatients may present with focal neurological deficits.
34Chronic Intestinal Schistosomiasis disease onset is insidious- Patients with symptomatic chronic schistosomiasis may present months to years after primary exposureportal hypertension with splenomegaly oesophagial varices, hypersplenism, ascitis, dyspepsia, flatulence, and pain are present in the left hypochondriumpulmonary hypertensionCNS lesions: spine - transverse myelitis cerebral – seizures (S. japonicum) -Dizziness, nausea, and increased intracranial pressure, Visual scintillation from occipital mass
35intestinal polyposis: intestinal granulomatosis: contractures of colon, intusseception, melena, Generalized lymphadenopathyFemale genital schistosomiasis- Postcoital bleeding, Genital ulceration, Irregular menstruation, Pelvic painCardiopulmonary schistosomiasis - larval pneumonitis with a cough, mild wheezing, and a low-grade fever, while in schistosomal cor pulmonale, easy fatigability, palpitations, dyspnea on exertion, and hemoptysis
50symptoms mimic any acute viral, bacterial, or malarial illness. Obtaining a careful travel history, including drinking water sources and recreational activities, is important. Symptoms are likely secondary to immune complex formation following egg deposition in tissues; the illness resembles serum sickness.
51Diagnosis: intestinal schistosomiasis 1. History of freshwater exposure2. Stool for O&P (egg counts and viability)3. Serology-- Elisa and Western Blot4. Antigen capture5. Eosinophilia6. Rectal snips or biopsies7. Liver biopsy8. Ultrasound or CT of abdomen
52Laboratory debris in urine eggs in urine (overnight-millipore) I.V.P. abnormalitiescystoscopyserology
53Schistosoma Mansoni in the Cecum ( Magnification Colonoscope.) This 34 year-old male, a routine colonoscopy wasperformed a Schistosoma Mansoni was found at the cecum.
55Management strategies: A. Treatment of local irritation (swimmers itch)B. Treatment of allergic reaction to cercarial entry (fever, rash, myalgia, pneumonitis - Katayama fever)C. Control of egg laying to prevent complicationsD. Treatment of complications
57Control of egg laying & complications: Praziquantel: Effective against all 3 forms↑ entry of Ca++ to cell memb, paralyze, detach & killTaken after meal without chewing (bitter)May increase symptoms of Katayama fever(↑ allergic reaction due to dead cestodes)Oxamniquine: Effective only for S. mansoniMetrifonate: Only for S. haematobium
58Outlook (PrognosisTreatment before significant damage or severe complications occur usually produces good results.
61Severe anemiaLow ̶ birth-weight babiesSpontaneous abortionHigher risk for ectopic pregnanciesEnd-organ diseasePortal hypertensionObstructive uropathyPregnancy complications from vulvar or fallopian granulomaCarcinoma of the liver, bladder, or gallbladder
62PreventionAvoid swimming or bathing in contaminated or potentially contaminated waterAvoid bodies of water of unknown safetySnails are an intermediate host for the parasite. Getting rid of snails in bodies of water used by humans would help prevent infection.