Schistosomiasis presented by Dr. Magdy Awny

Schistosomiasis (bilharzia, bilharziasis , snail fever) parasitic disease caused by blood flukes of the class Trematoda. Theodore Bilharz identified the parasite S. hematobium in Egypt in 1851 Schistosomiasis is the second most prevalent tropical disease in the world; malaria is the first. The disease is found mainly in developing countries in Africa, Asia, South America and the Middle East.

Types of schistosoma Type S. haematobium S. japonicum & S.mekongi S.mansoni  Type intestinal schistosomiasis urinary schistosomiasis Intestinal Disease Far east → japonicum Southeast Asia→ mekongi Africa the Middle East South America , Africa, and Middle East → S.mansoni West Africa → S. intercalatum Epidemio- logy spherical egg terminal spine lateral spine Egg

Life cycle of schistosoma video

Symptoms Dermatitis (itching) due to penetration of cercariae the human skin S. haematobium infection symptoms of the bladder are: 1- pain during urination 2- frequent need to urinate 3- blood in the urine

S. mansoni infection symptoms of the intestines are: 1-Abdominal pain 2-Bloody diarrhea 3-Abdomen may be swollen due to enlargement of the liver A blood test usually reveals signs of anemia

A 45-year-old, Egyptian male presented with severe hematemesis caused by esophageal varices. The patient had been a heavy smoker for 30 years, with no significant illness in the past. There was no organomegaly. Laboratory findings revealed elevated liver enzymes and positivity for hepatitis C infection. Abdominal ultrasound revealed mild hepatic cirrhosis. Stool examination for schistosome ova was positive for Schistosoma mansoni. ELISA for schistomiasis infection was also performed with serum, which showed high levels of antibodies to Schistosoma mansoni. Endoscopic sclerotherpy was used to sclerose his bleeding varices. For schistomiasis treatment, the patient received praziquantel 40 mg/kg in a single dose. The patient recovered successful during the next few days and was discharged from the hospital.

Diagnosis Urine and stool samples: Blood tests: Chest X-ray: Detects schistosomal eggs in the urine or stool using a microscope. Blood tests: 1- PCR testing (detection of schistosomal DNA) 2- Blood serology (antibodies against shistosomiasis) Chest X-ray: if the lungs are affected.

Diagnosis Scans: An ultrasound scan of the liver or the heart to see if they are infected or not CT or MRI scanning is used, especially if the brain or spinal cord is affected. Colonoscopy or cystoscopy: Taking samples at colonoscopy (looking inside the bowel with a telescope) or cystoscopy (looking inside the bladder with a telescope).

Drugs used for treatment Praziquantel (Biltricide):  induces ultrastructural changes in the teguments of adult worms, →↑ permeability to calcium ions.→↑ Calcium ions in the parasite cytosol → muscular contractions, paralysis of adult worms. By damaging the tegument membrane, praziquantel also exposes parasite antigens to host immune responses. These effects lead to dislodgement of worms from their intestinal sites. WHO-recommended single dosage of 40 mg/kg has shown it to be safe and relatively efficacious .

Metrifonate (Bilarcil) Is an organophosphorus compound that acts by inhibiting cholinesterase enzyme → paralyzing the worm.

Oxamniquine (Vansil) Irreversible inhibition of the nucleic acid metabolism of the parasites. The drug is activated by a single step, in which a schistosome sulfotransferase enzyme converts oxamniquine into an ester form, this electrophilic reactant is capable of alkylation of schistosome DNA. Side effect: Epileptiform convulsions (especially in patients with a history of convulsive disorders) Oxamniquine should not be taken during pregnancy

Complications of schistosomiasis Chronic liver damage and an enlarged spleen Colon ( or large intestine) inflammation Kidney and bladder obstruction Pulmonary hypertension Repeated blood infections (bacteria can easily enter the bloodstream through an inflamed colon) 6. Seizures 7. Bladder cancer

Esophageal Varices Are extremely dilated sub-mucosal veins in the esophagus mainly due to portal hypertension It may rupture causing life- threatening bleeding.

Sclerotherapy Is a procedure used to treat blood vessel malformations (vascular malformations). A medicine is injected into the vessels, which makes them shrink. to stop bleeding from varicose veins and hemorrhoids. e.g. hypertonic saline, ethanolamine, polidocanol and sodium tetradecyl sulfate

prevention

Prevention Avoid swimming or bathing in contaminated water Medications to prevent schistosomiasis drinking bottled water when traveling to endemic areas B-snail control: by using molluscicide e.g. Cu SO4 , quick lime there is no vaccine available for schistosomiasis

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