The effectiveness of annual versus biennial mass chemotherapy in reducing morbidity due to schistosomiasis: a prospective study in Gezira-Managil, Sudan.

The most serious complication of schistosomiasis is periportal fibrosis, which affects a large number of subjects in endemic areas. Population-based chemotherapy remains the most effective way of controlling this disease. In an attempt to find the best way to deliver chemotherapy to the endemic population, we compared the impact of repeated annual versus biennial mass chemotherapy on morbidity due to schistosomiasis in two villages in Gezira, Sudan. One village was given five rounds of mass chemotherapy annually in the years 1990-1994 while the other village was given three rounds of mass chemotherapy biennially from 1988 to 1994. Before treatment, these villages had similar intensity of infection and prevalence. One round of either annual or biennial treatment reduced the intensity of infection, but not prevalence or morbidity. After two rounds of annual chemotherapy, infection rates, bloody diarrhea, and fibrosis in those 20 years of age and less were significantly reduced. Two rounds of biennial chemotherapy had a similar effect on rates and bloody diarrhea; however, fibrosis was reduced only after the third round of biennial chemotherapy. Prevalence of hepatosplenomegaly increased after both treatment regimens. Reinfection was most prominent in those 5-14 years of age. These findings support the general notion that repeated chemotherapy may be needed in areas of high transmission of schistosomiasis. We recommend two rounds of annual mass chemotherapy to significantly reduce infection and morbidity.

Demonstration of urinary eosinophils in Schistosoma haematobium: a comparative study among three different stains.

Three stains, Hansel's stain, alkaline erythrocin B (AEB) and naphthalene black (NB), were used to demonstrate eosinophils in the urine of patients infected with Schistosoma haematobium. Hansel's stain was superior to the other two stains; it stained eosinophils bright red and their nuclei faint blue, and they were easily differentiated from neutrophils, lymphocytes, macrophages and epithelial cells. The method using AEB took longer than Hansel's stain and 10% of the specimens were lost during staining with this method. Like eosinophils, the neutrophils took up NB stain and their nuclei stained poorly with the counterstain.

Evaluation of eosinophiluria in the diagnosis of schistosomiasis hematobium: a field-based study.

Using Hansel's stain, eosinophiluria greater than 5% of total urinary white blood cells was found in 59% of a randomly selected population sample in an area endemic for schistosomiasis hematobium. The prevalence and mean level of eosinophiluria were significantly higher in infected subjects than in noninfected subjects (P less than 0.05). The sensitivity (80%), specificity (86%), and positive predictive value (82%) of eosinophiluria as a diagnostic index for schistosomiasis hematobium were significantly higher (Youdin index 0.66; P less than 0.05) than those of proteinuria, hematuria, and leukocyturia taken singly or in combination. However, unlike the latter three measurements, this method involves microscopy. There is a great need for a chemical method for measuring eosinophiluria.