A cost effective two step rapid diagnosis of urinary schistosomiasis in Zimbabwe.

OBJECTIVE: To assess the efficacy and applicability of questionnaires to determine schistosomiasis endemic areas in Zimbabwe. DESIGN: Cross sectional study. SETTING: Makonde District, Zimbabwe. SUBJECTS: Headmasters and children in Grades II to V of the 121 schools in the district. MAIN OUTCOME MEASURES: Number of completed questionnaires that were returned. Ranking of the most important diseases among the school children. RESULTS: Completed questionnaires were received from 110 (90.9%) schools. Of the 110 headmasters, 55.4% ranked schistosomiasis < or = 4 as one of the priority diseases affecting their children most. In addition, 44.2% gave blood in urine < or = 4 as one of the most frequent symptoms among their school children while 63.6% wanted action to be taken to prevent schistosomiasis and/or blood in urine among the children. A total of 38.3% of the children from 37 schools admitted having suffered from schistosomiasis during the last month while 37.4% of the children from 35 schools claimed to have experienced blood in their urine during the same period of time. The teachers found a prevalence of 46.1% while the research team found that 44.9% children had blood in their urine. CONCLUSION: The results of this study demonstrated that the questionnaire approach, besides the high diagnostic power, was the cheapest, costing only US$0.08 per child and 18 times cheaper than the filtration technique.

Progress in the control of schistosomiasis in Zimbabwe since 1984.

Schistosomiasis remains the second most important parasitic disease in Zimbabwe. In terms of its combined morbidity and prevalence, schistosomiasis is thought to be the most important helminth infection of man. Since 1984, a number of control programmes have commenced around the country and a national control programme aimed at reducing morbidity is being implemented. The strategy adopted in Zimbabwe is a community based approach integrated in the primary health care system.

PIP: Health facility utilization surveys in Zimbabwe indicate that schistosomiasis is 1 of the top 10 causes of clinic attendance, especially for children. It is in fact the second most important helminth infection of man. Poor nutrition and work performance in children, and pathological changes in the liver, bladder, and kidneys are associated with schistosomiasis. Various control projects established in Zimbabwe since 1984 are reviewed, beginning with results of the nationwide survey reported by Taylor and Makura assessing levels of Schistosoma haemotobium and Schistosoma mansoni among 14,614 school children from 157 schools around the country. Prevalence was found to range from zero to 97%. While the community and irrigation scheme pilot control projects combined with the overall national strategy should reduce the prevalence and morbidity of schistosomiasis, closer intersectoral cooperation is needed between governmental departments, provinces, and donor agencies, as well as better integration between the schistosomiasis control program and ongoing PHC activities.

Control of schistosomiasis transmission in newly established smallholder irrigation schemes.

The extent to which schistosomiasis can be controlled through careful design of the irrigation works, the operation schedule, the location of villages and the provision of safe water supplies and sanitation in smallholder irrigation schemes at Mushandike in south-east Zimbabwe is reported. The schemes provide land for 400 peasant families who are monitored for schistosomiasis soon after resettlement. Between April 1986 and August 1987 there was a marked reduction in overall prevalence following treatment. For Schistosoma haematobium, the reductions in 2 schemes were 53% and 82% and for S. mansoni, 82% and 100%, in spite of transmission in settlements upstream from the schemes. In contrast, in a nearby irrigated farm where no control measures were introduced, S. haematobium prevalence declined by only 31% while that for S. mansoni increased by 22% a year following treatment. These results are supported and strengthened by measurements of snail population sizes and their infection rates, cercarial densities in the water and incidence data for the human population, and suggest that the engineering and environmental control measures introduced are significant means of controlling transmission in smallholder irrigation schemes with the lowest recurrent costs.

Field evaluation of controlled release copper glass as a molluscicide in snail control.

Limited field evaluation of a new molluscicide, copper controlled release glass (CRG), was carried out in 4 human water contact sites in shallow and slow flowing streams in the highveld region of Zimbabwe during 1984 to 1986. The results indicate that the copper CRG has great potential as an inexpensive snail control agent to reduce schistosomiasis transmission. There was a marked reduction in snail numbers in the treated sites after application of 2 forms of the copper molluscicide; a "fast" CRG with approximately 24-h solution time in water and a "slow" CRG with about 1-year solution time. Snail numbers remained depressed during the observation period while frogs and fish were not affected. Fluctuations in snail numbers in the untreated sites showed no clear pattern, being erratic and unpredictable and probably attributable to seasonal effects. Problems of the correct amounts of molluscicide to apply to a site are to an extent overcome by knowledge of the copper binding capacity of the mud substrate. The mud sediment can be saturated by the "fast" release copper glass to achieve a snail killing concentration in the water which can be sustained by the "slow" release glass. It appears that the main difficulty in maintaining desirable copper levels in the water is flow, which causes rapid removal of copper from the treated waterbody. Thus, under field conditions on the highveld region of Zimbabwe, the CRG molluscicide is likely to be effective only during the stable conditions of the dry season which is, however, the main transmission period.

Prevalence and distribution of schistosomiasis in Zimbabwe.

Surveys for schistosomiasis of 14 619 eight- to ten-year-old children from 157 schools in Zimbabwe are reported. Zimbabwe is divided into three regions on the basis of differing prevalences of Schistosoma haematobium, with mean prevalence levels in each zone of 63.2, 37.1 and 14.3%. Two regions were identified for S. mansoni, with mean prevalence levels of 15.2 and 1.5%. In most regions Commercial Farming areas were shown to have higher levels of infection than Subsistence Farming areas. Females showed a significantly lower prevalence of infection with S. haematobium than males in all areas. Age prevalence surveys in support of the major survey showed the seven- to 20-year-old age group to contain 91.5% of the heavy infections with S. haematobium and 83.7% of the heavy infections with S. mansoni. The availability of surface water is recognized as the major factor governing the distribution and prevalence of schistosomiasis. Control of schistosomiasis is briefly discussed.