Ans. a (S. hematobium) (Ref. H - 18th/ ch. 219)SCHISTOSOMIASIS (BILHARZIA)Distribution and important species of Schistosoma are:# S. japonica is found in Central and Eastern China, and the Philippines and nearby islands; and primarily affects the liver and intestines.# 5. mansoni is found in Africa, the Eastern Mediterranean, the Caribbean, and South America and primarily affects the liver and intestines.# S. haematobium is found in Africa, the Middle East, and Eastern Mediterranean and primarily affects the urinary tract.# S. mekongi is found in Southeast Asia and primarily affects the liver and intestines.Incubation:# Symptoms of acute schistosomiasis begin about a month after infection.Signs and Symptoms# Acute schistosomiasis ->>Katayama fever.Q# The last (chronic) stage varies according to species, i.e., S. japonica, 5. mansoni, and S. mekongi primarily affect liver and intestines; while S. haematobium primarily affects the urinary tract.# In general, patients with chronic schistosomiasis tend to present in developed countries with lethargy, colicky abdominal pain, mucoid/bloody diarrhea, or dysuria and hematuria.# Chronic hepatosplenic schistosomiasis is a consequence of eggs retained in tissue and prolonged infection - usually of > 10 years duration.# Fibrosis may cause portal hypertension, splenomegaly, or esophageal or gastric varices.Q# Chronic genitourinary schistosomiasis is associated with chronic 5. haematobium infection.# Hematuria and dysuria are common from the acute through chronic stages. Bladder cancer rates are increased in endemic areas. Salmonella infection concurrent with schistosomiasis is common and is resistant to treatment unless the schistosomiasis is also treated.Diagnosis# Diagnosis of S. japonicum and S. mansoni is by the presence of ova in feces or tissue. Diagnosis of S. haematobium is by the presence of ova in urine or tissue. However, ova loads are not always sufficient for diagnosis, especially in long-standing chronic illness. Immunofluorescent antibody tests and antigen detection assays are increasingly used.# "Fetal head" bladder calcification may be shown in X-rays in chronic S. haematobium infection. QTreatment# For S. haematobium and S. mansoni, praziquantel 20/kg po bid for one day; for S. japonica and S. mekongi, praziquantel 20/kg po tid for one day are the treatments of choice.# S. mansoni may also be treated with oxamniquine in a single po dose (with food) of 15 mg/kg. S. haematobium in North and East Africa may be treated with metrifonate 7.5-10 mg/kg every other week for a total of 3 doses.Also Know:# The second most common urologic cancer and the most frequent malignant tumor of the urinary tract is bladder cancer. Usually a transitional cell carcinoma. Most prevalent in men during the sixth and seventh decades. Risk factors include smoking, diets rich in meat and fat, schistosomiasis, chronic treatment with cyclophosphamide, and exposure to aniline dye (a benzene derivative).# Causes of portal hypertesnion are as follows: 1. Presinusoidal: Splenic or portal vein thrombosis, schistosomiasis. granulomatous disease. 2. Sinusoidal: Cirrhosis, granulomatous disease. 3. Postsinusoidal: Right heart failure, constrictive pericarditis, hepatic vein thrombosis.