Anthelmintic screening of Zimbabwean plants traditionally used against schistosomiasis.

Extracts of 23 plant species used popularly against schistosomiasis in Zimbabwe were screened for their anthelmintic effect. Schistosomules of the trematode Schistosoma mansoni and cysticercoids of the cestode Hymenolepis diminuta were studied in vitro. The material consisted of 58 plant extracts, of which 37 killed the newly excysted cysticercoids within an hour, when incubated in a culture medium. Lethal concentrations varied from 0.8 to 103 mg/ml. All plant extracts showed activity against the tapeworms after 24 h. Ten of the best extracts were also tested against schistosomules. Five of these extracts showed activity. Lethal concentrations varied from 0.6 to 33.8 mg/ml of dry plant material. Extracts of stem and root from Abrus precatorius (Fabaceae), of root bark and leaves from Ozoroa insignis (Anacardiaceae) and of root bark from Zizyphus mucronata (Rhamnaceae) gave the best results against tapeworms. The best results against schistosomules were obtained with stem and root extracts from Abrus precatorius (Fabaceae) and stem bark from Elephantorrhiza goetzei (Mimosaceae). Although the activity of root and root bark extracts commonly used in traditional medicine was verified in this study, our results showed that also extracts from leaf and stem can be effective anthelmintics.

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.

Schistosomiasis infection in relation to the ABO blood groups among school children in Zimbabwe.

The study aimed to establish if there was any relationship between the blood group of the human host and schistosomiasis prevalence, intensity, incidence and related organ pathology. Urine and stool specimens were collected from the 735 school children attending a rural school in Zimbabwe to determine the Schistosoma haematobium and S. mansoni infection status of the children. The parasitology results were used to calculate prevalence and intensity of schistosomiasis infection. All the children, irrespective of infection status, were examined for signs of organ damage using ultrasonography before those that were infected were treated using a single dose of praziquantel. A blood specimen was taken from each child for blood group determination. Exactly 1 year later, parasitology was repeated to allow calculation of annual incidence of schistosomiasis infection. Of the children studied, 212 (28.8%) were of blood group 'A', 156 (21.2%) were of blood group 'B' while 367 (49.9%) belonged to blood group 'O'. The prevalence of S. haematobium was 59.6% (n = 438) while that of S. mansoni was 15.60% (n = 115). S. haematobium infection was detected among 129 (60.8%) children belonging to blood group 'A': 225 (61.30%) of blood group 'O' and 84 (53. 80%) of those belonging to blood group 'B'. S. mansoni infection was detected among 65 (30.70%) blood group 'A' children while 37 (10.10%) blood group 'O' and 13 (8.30%) blood group 'B' children were infected. Intensity, annual incidence of S. haematobium infection and related organ pathology was significantly higher among children of blood group 'A' and lowest among blood group 'O' children (P < 0.01, F-value = 6.13). Similarly, S. Mansoni intensity and incidence of infection and related liver lesions were highest among children of blood group 'A' (P < 0.005, F-value = 11.45).

Traditional herbal remedies used for the treatment of urinary schistosomiasis in Zimbabwe.

A total of 286 traditional healers, 85% of them registered with the Zimbabwe National Traditional Healers' Association (ZINATHA), in five administrative provinces of Zimbabwe, were interviewed to assess their knowledge about the signs and symptoms of urinary schistosomiasis. Information on the names of plants used to treat Schistosoma haematobium infections was solicited. Haematuria was mentioned by 99% of the traditional healers to be the most obvious sign of S. haematobium infection. General body weakness, increased urinary frequency and pain on micturition also were reported to be some of the signs of infection. Eight plant materials were identified as the most commonly used for the treatment of S. haematobium. The plants were identified and parts collected to investigate their antischistosomal properties. The plant materials were prepared according to the guidelines of the traditional healers and their efficacy determined by administering the crude extracts orally to hamsters infected with S. haematobium cercariae. The results obtained suggested that plant extracts from Abrus precatorius (Leguminosae), Pterocarpus angolensis (Leguminosae) and Ozoroa insignis (Anacardiaceae) were lethal to adult schistosomes.

The physical fitness and work performance of agricultural workers infected with Schistosoma mansoni in Zimbabwe.

Stool specimens were collected from 1995 sugarcane cutters on the Hippo Valley and Triangle sugar estates, Zimbabwe, in order to determine the prevalence and intensity of Schistosoma mansoni infection. Pathological changes normally ascribed to S. mansoni infection were assessed in the infected cutters, by ultrasonography before treatment. The height, weight, age, haemoglobin levels, blood pressure and body fat of the infected and uninfected control study subjects, standardized by age, were determined. Those with elevated blood pressure were excluded from the study. Physical fitness and work performances were assessed in 287 infected and 210 uninfected cane cutters aged (mean +/- S.D.) 36.5 +/- 7.5 years. Despite the finding that all the subjects were of good nutritional status and generally physically fit, a t-test showed a significant improvement (P < 0.01) in the performance of the infected cutters following treatment; age-related physical performance, measured by the Harvard Step Test, increased by 4.3% and work output, measured as the amount of cane cut in a given time, rose by 16.6%. Although the physical and work performances of the uninfected control subjects also increased over the same period, this trend, attributed to occupational physical exercise, was not statistically significant (P > 0.05). Significant correlations were found between both infection intensity-related pre-treatment physical fitness (P < 0.05) and work performance (P < 0.01) and prevalence of Symmers' peri-portal fibrosis.

Morbidity due to Schistosoma mansoni among sugar-cane cutters in Zimbabwe.

Quantitative determination of Schistosoma mansoni infection was carried out on 1995 cane cutters of the Hippo Valley and Triangle Sugar Estates. A total of 315 cutters were chosen for the study on the basis of S. mansoni infection and lack of anti-schistosomal chemotherapy during the previous three years. Stool consistency and blood and mucus in stool were determined for all the infected cutters. Overt and occult blood in stool was detected in a significantly high number of infected people compared to the control subjects (chi 2 p less than 0.001). However, the blood loss was found to have no anaemia-producing effect as determined by haemoglobin and red blood cell counts. Watery stool was prevalent among people with egg output exceeding 500 eggs per gram of stool. Mucus in stool was found to be more prevalent among infected people compared to the control subjects but the difference was not significant (p greater than 0.05). Symmer's periportal fibrosis (PPF) of various degrees of severity was detected in 47% of the infected people and grade one liver fibrosis was found in 7.5% of the control subjects (p less than 0.0001). Some 54.5% of those infected complained of abdominal pains compared to 35% of uninfected controls (p less than 0.01). There was a significant difference in the rate of absenteeism from work due to abdominal pains and diarrhoea among the infected and uninfected cane cutters (p less than 0.02).

A cross-sectional study on the prevalence and intensity of schistosomiasis among sugar cane cutters in Zimbabwe.

A schistosomiasis prevalence and intensity survey was carried out among sugar cane cutters of Hippo Valley and Triangle, the two largest irrigated sugar estates in Zimbabwe. Urine and stool specimens were collected for determination of schistosomiasis infection from 1995 cane cutters. A total of 315 (15.8pc) cutters were found to be infected with Schistosoma mansoni while 163 (8.2pc) were found to be positive for S. haematobium. The arithmetic mean egg count (AMEC) and geometric mean egg count (GMEC) for the different age groups into which the cane cutters were divided was calculated. The prevalence and intensity of S. mansoni increased with age while the opposite was true for S. haematobium. The factors contributing to this observation are discussed.

The use of Phytolacca dodecandra berries in the control of trematode-transmitting snails in Zimbabwe.

Phytolacca dodecandra, a plant with berries of a known molluscicidal potency, was cultivated in Chiweshe. Studies on the snail population density of Bulinus globosus and Lymnaea natalensis as well as schistosome infection rates in the former were carried out in two streams, in one of which a water extract of P. dodecandra berries was applied in late April and May 1987. Snail sampling was carried out twice a month from April 1986 to April 1988, that is for 12 months prior to and after the mollusciciding exercise. B. globosus snails obtained from both streams were examined for infection by cercarial shedding before they were returned to their sites of collection. The 8-h water extract of P. dodecandra was applied to human watercontact points. The two applications were aimed at achieving a concentration of 50 mg/l. No snails were recovered from the experimental sites for a period of 7 months after the mollusciciding exercise. Snails were recovered in the treated sites only after the onset of the rainy season.

Knowledge, attitudes and practices among rural communities in Zimbabwe in relation to Phytolacca dodecandra--a plant molluscicide.

Questionnaires about schistosomiasis and Phytolacca dodecandra, a plant molluscicide with potential to control schistosomiasis transmitting snails, were administered to 271 women and 168 men in two communal areas where the plant grows naturally, and in a further two areas where no records of the plant exist. 78.9% of the respondents thought that schistosomiasis was a dangerous disease with blood in urine being the most recognised symptom. 11.8% said that snails were involved in the transmission of the disease, although their role in sustaining the life cycle of the schistosome parasite was not understood. Knowledge about P. dodecandra was restricted to people resident in areas where the plant grows naturally and to immigrants from areas where it is known to grow. The most common use of the plant was as a floor polish. Knowledge of uses of the plant were found to be related to the sex of the respondents. Seventy-seven percent of the people interviewed were prepared to cultivate the plant for self-help schistosomiasis control programmes. Of the 23% that were not willing to cultivate P. dodecandra, 47.7% cited scarcity of land as the main obstacle. Other reasons were lack of knowledge about the plant (21%), lack of confidence in the success of such self-help programmes (11.2%) and indifference due to old age (20%).