Schistosomiasis (schistosoma)

                

· The most common types in Egypt are Schistosoma haematobium and Schistosoma mansoni.

· Children are infected through contact with water contaminated with cercariae.

· Cercaria emerge from the infected snails and are capable to penetrate intact human skin.

· Cercaria they migrate to the lungs and finally to the liver.

· The adult worms migrate to specific anatomic sites characteristic of each species.

· Schistosoma haematobium adults are found in the perivesical and periureteral venous   plexus, while Schistosoma mansoni adults are found in the inferior mesenterirc veins.

Clinical manifestations

· Cercarial penetration of human skin may result in pruritic rash (swimmer’s itch).

· Acute schistosomiasis (Katayama fever) may occur, particularly in heavy infection 4-8 weeks after exposure. This is a serum sickness-like syndrome that is manifested by an acute onset of fever, chills, sweating, lymphadenopathy, hepatosplenomegaly and eosinophilia.

· Schistosoma haematobium usually manifests by frequency of urine, dysuria and terminal   hematuria.

· Moderate to severe pathologic lesions have been demonstrated in the urinary tract and the terminal stages of schistosomiasis haematobia are associated with chronic renal failure and secondary infections.

· Chronic schistosoma mansoni infection presents with colicky abdominal pain and bloody diarrhea.

· Hepatosplenomegaly, portal hypertension, ascites and hematemesis may be the initial presentation.

· Schistosome eggs may escape into the lungs, causing pulmonary hypertension and cor- pulmonale. The schistosome may migrate to the brain vasculature and produce localized  lesions that cause seizures.

Diagnosis

 Schistosome eggs are found in urine and stool. A volume of 10ml of urine should be collected around midday, which is the time of maximal egg excretion, and filtered for diagnosis of            S. haematobium infection.

Treatment

The drug of choice is praziquantel (40 mg/kg/day divided into two doses for one day).

Prevention

· Transmission of infection may be decreased by reducing the parasite load in the population. This goal may be achieved by the availability of oral, single- dose, effective chemotherapeutic agents.

· Other measures, particularly improved sanitation and focal application of molluscicides, may be useful.

· Control of schistosomiasis is closely linked to economic and social development.