Evaluation of the therapeutic efficacy of praziquantel against schistosomes in seven countries with ongoing large-scale deworming programs.

The World Health Organization (WHO) recommends periodic assessment of the therapeutic efficacy of praziquantel (PZQ) to detect reduced efficacy that may arise from drug resistance in schistosomes. In this multi-country study (2014), we assessed the therapeutic efficacy of a single oral dose of PZQ (40 mg/kg) against Schistosoma mansoni (Brazil, Cameroon, Ethiopia, Mali, Madagascar and Tanzania), S. haematobium (Cameroon, Ethiopia, Mali, Tanzania and Zanzibar) and S. japonicum (the Philippines) infections in school-aged children, across a total of 12 different trials. Each trial was performed according to the standardized methodology for evaluating PZQ efficacy as described by the WHO. Overall, therapeutic efficacy, measured as the reduction in arithmetic mean of schistosome egg counts following drug administration (egg reduction rate; ERR), was high for all three schistosome species (S. mansoni: 93.4% (95%CI: 88.8-96.8); S. haematobium: 97.7% (95%CI: 96.5-98.7) and S. japonicum: 90.0% (95%CI: 68.4-99.3). At the trial level, therapeutic efficacy was satisfactory (point estimate ERR ≥90%) for all three Schistosoma species with the exception of S. mansoni in Cameroon where the ERR was 88.5% (95%CI: 79.0-95.1). Furthermore, we observed that in some trials individual drug response could vary significantly (wide 95%CI) and that few non-responsive individuals could significantly impact ERR point estimates. In conclusion, these results do not suggest any established reduced efficacy of the standard PZQ treatment to any of the three schistosome species within these countries. Nevertheless, the substantial degree of variation in individual responses to treatment in some countries underpins the need for future monitoring. The reported ERR values serve as reference values to compare with outcomes of future PZQ efficacy studies to ensure early detection of reduced efficacies that could occur as drug pressure continues increase. Finally, this study highlights that 95%CI should be considered in WHO guidelines to classify the therapeutic efficacy of PZQ.

The relationship between helminth infections and low haemoglobin levels in Ethiopian children with blood type A.

The current study was conducted to evaluate the nature of association of ABO blood type with helminth infection and related reduction in haemoglobin concentration. Stool samples were collected from 403 school-age children attending Tikur Wuha Elementary School from February to April 2011. Helminth infection was examined using formol-ether concentration and thick Kato-Katz (two slides per stool specimen) techniques. Haemoglobin level was determined using a HemoCue machine and ABO blood type was determined using the antisera haemagglutination test. Nutritional status was assessed using height and weight measurements. Out of 403 children examined, 169, 120, 96 and 18 had blood type O, A, B and AB, respectively. The prevalences of helminth infections were 46.9% for hookworm, 24.6% for Schistosoma mansoni, 4.2% for Ascaris lumbricoides, 1.7% for Trichuris trichiura and 58.3% for any helminth species. The relative odds of infection with at least one helminth species was significantly higher among children with blood type A (adjusted odds ratio (AOR), 2.10; 95% confidence interval (CI), 1.28-3.45) or blood type B (AOR, 2.08; 95% CI, 1.22-3.56) as compared to children with blood type O. Among children infected with helminths, mean haemoglobin concentration was lower in those with blood type A than those with blood type O (ß, -0.36; 95% CI, -0.72 to -0.01). The relative odds of hookworm infection (AOR, 1.78; 95% CI, 1.08-2.92) and related reduction in haemogobin levels (ß, -0.45; 95% CI, -0.84 to -0.04) was higher among children with blood type A as compared to those with blood type O. Although the difference was not significant, the relative odds of S. mansoni or A. lumbricoides infections and related reduction in haemoglobin levels was also higher in children with blood type A or B as compared to children with blood type O. In conclusion, children with blood type A are associated with an increased risk of helminth, particularly hookworm, infection and related reduction in haemoglobin level. The mechanisms by which blood type A makes children susceptible to helminth infection and a related reduction in haemoglobin level ought to be investigated.

The association between multiple intestinal helminth infections and blood group, anaemia and nutritional status in human populations from Dore Bafeno, southern Ethiopia.

In this cross-sectional study, the associations between helminth infections and ABO blood group, anaemia and undernutrition were investigated in 480 febrile outpatients who visited Dore Bafeno Health Centre, southern Ethiopia, in December 2010. Stool specimens were processed using the Kato-Katz method and examined for intestinal helminth infections. Haemoglobin level was measured using a HemoCue machine and blood group was determined using an antisera haemagglutination test. Nutritional status of the study participants was assessed using height and weight measurements. Among the study participants, 50.2% were infected with intestinal helminths. Ascaris lumbricoides (32.7%), Trichuris trichiura (12.7%), Schistosoma mansoni (11.9%) and hookworm (11.0%) were the most frequently diagnosed helminths. The odds of infection and mean eggs per gram of different intestinal helminth species were comparable between the various blood groups. Among individuals who were infected with intestinal helminth(s), the mean haemoglobin level was significantly lower in individuals harbouring three or more helminth species and blood type AB compared to cases with double or single helminth infection and blood type O, respectively. The odds of being underweight was significantly higher in A. lumbricoides and T. trichiura infected individuals of age ≤ 5 and ≥ 20 years, respectively, when compared to individuals of the matching age group without intestinal helminths. In conclusion, infection with multiple intestinal helminths was associated with lower haemoglobin level, which was more severe in individuals with blood type AB. Future studies should focus on mechanisms by which blood group AB exacerbates the helminth-related reduction in mean haemoglobin level.

Prevalence and risk factors of wheeze and eczema in 1-year-old children: the Butajira birth cohort, Ethiopia.

BACKGROUND: The rising global prevalence of asthma and other allergic conditions has been linked to potential aetiological factors influencing the developing immune system. OBJECTIVE: To investigate the prevalence and associated risk factors for wheeze and eczema in 1-year-old children in a birth cohort from Butajira, Ethiopia. METHODS: In 2005/6, a population-based cohort of 1065 pregnant women was established. At 1 year of age, data on wheeze and eczema in the children were collected from the mother via an interview-administered questionnaire, along with numerous demographic and lifestyle factors. A stool sample was also obtained from the child for geohelminth analysis. RESULTS: The prevalence of wheeze was 11.5% (103/899) and eczema 8.6% (77/899). Independent predictors of wheeze were maternal allergic history [adjusted OR (AOR)=3.00, 95% CI 1.23-7.36], paternal allergic history (AOR=2.59, 95% CI 1.08-6.25), increasing household size (P for trend=0.023; AOR=3.54, 95% CI 1.31-9.56 for 7+ vs. 1-3 individuals) and paracetamol use by the child (overall P<0.001; AOR 11.04, 95% CI 4.30-28.31 for 4+ tablets in past month vs. never). Factors independently associated with eczema were maternal allergic history (AOR=3.68, 95% CI 1.54-8.77), household size (overall P=0.035; AOR=0.45, 95% CI 0.23-0.87 for 4-6 individuals relative to 1-3) and place of sleeping (overall P<0.001; AOR=0.29, 95% CI 0.10-0.82 for floor vs. bed/platform). CONCLUSION: These findings support the hypothesis that eczema in early life in these children is a manifestation of allergy, while wheezing is probably due to infection as well as allergy.

Field-based evaluation of a reagent strip test for diagnosis of schistosomiasis mansoni by detecting circulating cathodic antigen (CCA) in urine in low endemic area in Ethiopia.

The sensitivity, specificity, positive and negative predictive values of a reagent strip test for the diagnosis of schistosomiasis mansoni by detecting circulating cathodic antigen (CCA) in urine were evaluated using 184 stool and urine samples collected from schoolchildren living in relatively low endemic area of schistosomiasis mansoni in Ethiopia. A combined result of stool samples processed by Kato and formol-ether concentration methods was used as gold standard. The results showed that detection of CCA in urine using reagent strip test was slightly higher than the combined results of the stool techniques (65.2 % vs 42.4 %, p > 0.05) in suggesting the prevalence of the disease. The sensitivity, specificity, positive and negative predictive values of the reagent strip test were 76.9 %, 43.4 %, 50 % and 71.9 %, respectively. The result of egg counts using Kato method suggested that detection of urine CCA could be used to indicate the intensity of infection. Nevertheless, like that of stool examination, the reagent strip test was found to be less sensitive in case of light to moderate infections. About 23.1 % of the study children who were excreting the eggs of the parasite were found negative by the reagent strip test. The relative insensitivity of a reagent strip test in low intensity of infection necessitates for the development of more sensitive assay that can truly discriminate schistosome-infected from non-infected individuals.

Evaluation of circulating cathodic antigen (CCA) strip for diagnosis of urinary schistosomiasis in Hassoba school children, Afar, Ethiopia.

A total of 206 urine samples collected from Hassoba Elementary schoolchildren, Afar, Ethiopia, a low Schistosoma haematobium endemic setting, was diagnosed to evaluate the performance of CCA strip using double references, urine filtration technique and urinalysis dipstick (Combur 1.0 Test) that detect schistosome eggs and blood in urine, respectively. The former was used as a gold standard reference method. Sensitivity, specificity, positive and negative predictive values for the CCA were 52%, 63.8%, 56.7% and 59% respectively, with reference to urine filtration technique whereas these parameters were 50.4%, 62.4%, 55.6% and 57.5% respectively, with reference to Combur 10 Test. 47 S. haematobium egg-positive children were found negative by CCA strip while 38 egg-negative children were found positive by CCA strip. Moreover, among the pre-tests done in duplicate, inconsistent results were also recorded. Assays were also compared with regard to the cost of equipment and reagents, speed and simplicity of use. Though CCA strip was found to be rapid and could be performed with minimal training, it was found to be expensive (US $ 4.95 per test) to use it for large-scale field use even if its diagnostic value would have been satisfactory. Further development and standardization of the CCA strip are required for its applicability for field use. It is also recommended that its cost per strip should be substantially cut down if it is to be used in poor schistosomiasis endemic countries.

Screening of Echinops ellenbeckii and Echinops longisetus for biological activities and chemical constituents.

Members of the genus Echinops in the family of Asteraceae are widely used in Ethiopian herbal medicine for the treatment of various diseases and illness such as migraine, diarrhea, heart pain, different forms of infections, intestinal worm infestation and hemorrhoid. Hydroalcoholic extracts of the root, flower head, leaf and stem of Echinops ellenbeckii O. Hoffm. and Echinops longisetus A. Rich were investigated for their chemical constituents and biological activities. The presence of alkaloids, saponins, phytosterols, polyphenols and carotenoids in the different parts of the plants was observed whilst anthraquinones were not detected. The leaf extracts of both plants and stem extract of E. longisetus showed strong inhibitory activity against cultures of Staphylococcus aureus. None of the extracts were found to be active against Gram-positive organisms. The flower extract of E. ellenbeckii showed strong inhibitory activity against Candida albicans. Root and flower extracts of the plants investigated showed lethal activity against earthworms. Moreover, the extracts of the roots of both plants showed molluscicidal activity against schistosome-transmitting snail hosts. The biological activities observed were dose dependent.

Control of Biomphalaria pfeifferi population and schistosomiasis transmission in Ethiopia using the soap berry endod (Phytolacca dodecandra), with special emphasis on application methods.

The endod (Phytolacca dodecandra)-based schistosomiasis mansoni control project was implemented in Ethiopia between 1994 and 1999. The aim was to develop an effective, cheap and sustainable method of controlling schistosomiasis. First, different formulations of the Ethiopian endod strain 44 (E-44) were compared for potency in the laboratory. Secondly, spray and drip-feeding methods were compared for simplicity and effectiveness in the field. Lastly, the efficacy of endod powder soap was compared with the endod spray method. In Bati stream, endod powder soap was distributed to the residents every weekend at laundry sites. In Worke stream, endod was sprayed along a 1-km stretch of the stream at 3-month intervals. No endod was applied in Harbu stream. The immediate and long-term effects of endod application on the snail population and schistosomal infection were determined. Using the spray method, 100% snail mortality could be obtained, and it was simpler and more effective than the drip-feeding method. Snail mortality ranged from 20 to 100% using endod soap. There was a progressive decline in the snail population and infection in Bati stream compared with Worke stream, mainly due to sustained use of endod soap. The advantages and disadvantages of the different endod delivery systems are discussed.

Comparative efficacy of albendazole and three brands of mebendazole in the treatment of ascariasis and trichuriasis.

OBJECTIVE: To evaluate the comparative efficacy of 400 mg albendazole (Smith Kline Beecham) as a single dose and three brands of mebendazole (Janssen, Unibios and East African Pharmaceuticals) at doses of 100 mg twice a day for three consecutive days in the treatment of single or mixed infections with Ascaris lumbricoides and or Trichuris trichiura in four treatment groups of school children. DESIGN: Randomized trial. SETTING: Wondo-Genet, southern Ethiopia. SUBJECTS: School children, aged six to nineteen years. RESULTS: The percentage cure rate and egg reduction rate obtained with albendazole and mebendazole from the three brands were not significantly different in the treatment of ascariasis. However, significant differences were found among the percentage cure rates and egg reduction rates of the four treatment groups in the treatment of trichuriasis. Comparatively, high cure rate (89.8%) and egg reduction rate (99.1%) were observed in vermox (Janssen) treated group followed by Unibios (India) treated group (53.3% and 96.53% cure and egg reduction rates, respectively), whereas low cure rate (17.1%) and egg reduction rate (69.8%) were seen in the albendazole treated group. CONCLUSION: The results of this study suggest that in areas of single or mixed infections with Trichuris trichiura and/or Ascaris lumbricoides are common public health problems and where laboratory facilities are not available to make parasite identification, mebendazole (particularly vermox, a product of Janssen laboratory) would be the drug of choice to treat trichuriasis and ascariasis. However, either mebendazole from the different brands or albendazole is effective in the treatment of ascariasis in areas where trichuriasis is not prevalent.

Control of Schistosoma mansoni by the soapberry Endod (Phytolacca dodecandra) in Wollo, northeastern Ethiopia: post-intervention prevalence.

OBJECTIVES: To record the effect of Endod soap and spraying of soaked Endod suspension on the prevalence of human schistosomiasis. DESIGN: A cross-sectional epidemiological study in which pre- and post-intervention parasitological results were compared. SETTING: Kemise, Bati and Harbu towns in northeastern Ethiopia. SUBJECTS: The study subjects included all members of the five per cent households systematically selected from the three towns. RESULTS: In Kemise town, where suspension of ground Endod was sprayed on the stream containing infected snails, the prevalence of the disease was reduced from 59% to 53% and the mean intensity of infection was reduced from 239 eggs per gram (EPG) of faeces to 99 EPG (p < 0.05). In Bati town where Endod soap approach was used, the respective reduction in the prevalence and intensity of infection was from 51% to 43% and from 195 EPG to 162 EPG (p < 0.05). There was also a significant reduction of the disease in the control town probably due to the effects of praziquantel treatment and other factors. CONCLUSION: The reduction achieved in the prevalence and intensity of schistosomiasis after an intervention period of four years was limited. This observation corroborates the fact that molluscicides must always be considered as supplementary to chemotherapy in the control of schistosomiasis. Although both approaches can be used, the spraying approach appears to be simpler and more feasible because two or three times yearly application of Endod suspension would suppress snail population and reduce transmission. Nevertheless, the choice as to what approach to use must be made on the basis of community preference, and for some soap-effect of Endod would be attractive

Implication of Papio anubis in the transmission of intestinal schistosomiasis in three new foci in Kime area, Ethiopia.

Epidemiological studies were conducted in the Lake Langano area in the Rift Valley of Ethiopia to determine the occurrence of schistosomiasis and assess factors involved in its transmission. Microscopic examination of faecal specimens from free ranging Papio anubis (anubis baboon) troops from Bishan Gari and Burka Dita forest reserves revealed Schistosoma mansoni eggs with a prevalence of 12.1% (11/91) and 26.2%(34/130), respectively. The eggs were viable as confirmed by miracidial hatching and infectivity tests. Out of the total 12 communities (three schools, five villages and one herdsmen community) surveyed for schistosomiasis around Lake Langano, individuals excreting S. mansoni eggs were found in nine communities with prevalence of infection ranging from 1.4 to 43%. The intensity of infection ranged from 24 EPG (eggs per gram of faeces) to 243 EPG. Excretion of viable eggs by the baboons indicate that they play a role in maintenance of S. mansoni infection in the locality. The detection of S. mansoni eggs in young children, collection of cercarial-infected Biomphalaria pfeifferi in water bodies, and establishment of S. mansoni infection in lab-bred mice have confirmed establishment of transmission foci in Kime area, south-east of Lake Langano. However, the lake itself does not seem to support transmission of schistosomiasis since no snails were found along the shore of the Lake. Further investigations are indicated to fully elucidate the role baboons play in the epidemiology of schistosomiasis in the Rift Valley of Ethiopia. The risk of introduction of water-based development projects in these new endemic foci in relation to S. mansoni infection in the baboons is discussed.

Satellite climatology and the environmental risk of Schistosoma mansoni in Ethiopia and east Africa.

Annual and seasonal composite maps prepared from the normalized difference vegetation index (NDVI) and earth surface maximum temperature (T(max)) satellite data from the archives of the Global land 1-km program of the United States Geological Survey (USGS) were studied for. their potential value, using geographic information system (GIS) methods, as surrogates of climate data in the development of environmental risk models for schistosomiasis in Ethiopia. Annual, wet season and dry season models were developed and iteratively analyzed for relationships with Schistosoma mansoni distribution and infection prevalence rates. Model-predicted endemic area overlays that best fit the distribution of sites with over 5% prevalence corresponded to values of NDVI 125-145 and T(max) 20-33 degrees C in the annual composite map, NDVI 125-145 and T(max) 18-29 degrees C for the wet season map, and NDVI 125-140 and T(max) 22-37 degrees C for the dry season map. The model-predicted endemic area was similar to that of a prior model developed using an independent agroecologic zone data set from the United Nations Food and Agriculture Organization (FAO). Results were consistent with field and laboratory data on the preferences and limits of tolerance of the S. mansoni-Biomphalaria pfeifferi system. Results suggest that Global 1-km NDVI and T(max), when used together, can be used as surrogate climate data for development of GIS risk assessment models for schistosomiasis. The model developed for Ethiopia based on global 1-km satellite data was extrapolated to a broader area of East Africa. When used with FAO agroecologic zone climate data limits of <27 degrees C for average annual mean temperature and annual moisture deficits (annual rain-annual potential evapotranspiration) of <-1300 mm, the model accurately represented the regional distribution of the S. mansoni-B. pfeifferi system in the East Africa extrapolation area.

Investigation into the cercariacidal and miracidiacidal properties of Endod (Phytolacca dodecandra) berries (type 44).

Aqueous extract of ground Endod (Phytolacca dodecandra) berries (Type 44) was investigated for its cercariacidal and miracidiacidal properties. Aqueous extract of the berries prevented snails from being infected by miracidia at a concentration of 4 ppm. Assessment of cercariacidal activity of Endod berries indicated that mortality of cercariae exposed to aqueous extract of Endod berries increased with increase in concentration of the test material and exposure time. Viability assessment test showed that pre-treatment of the cercariae with 12 ppm of the extract completely inhibited infection of mice by cercariae and significantly reduced tissue egg deposition and worm establishment in the mice (ANOVA, P < 0.05) The potential use of (Phytolacca dodecandra) berries against schistosome larval stages in fresh water in a schistosomiasis control program is discussed.

Transmission of intestinal schistosomiasis in Addis Ababa, Ethiopia.

Malacological and parasitological surveys were made in Bole-Kotobe area in Addis Ababa in April 1996 to investigate the transmission of intestinal schistosomiasis. Malacological survey conducted in Kotobe river showed Schistosoma mansoni cercarial infection rate of 2.6% (one out of 38) in Biomphalaria pfeifferi. In a total of 197 stool specimens from school children examined using Kato thin smear method in Misrak Bar Number 1 and Wondirad Elementary and Junior Secondary Schools, the overall prevalence rate of Schistosomas mansoni was 4% and 10%, respectively while the intensity of infection was 66 and 37 eggs per gram (EPG) of stool, respectively. Out of the 13 children found infected in the two schools, nine gave a history of having swam in Kotobe river and had never been outside of Addis Ababa since birth. The collection of B. pfeifferi infected with S. mansoni, the establishment of the isolated S. mansoni in laboratory mice and the finding of schistosome infected children who had never been outside of Addis Ababa confirmed that transmission of intestinal schistosomiasis is actually taking place in Addis Ababa. Further surveys in other water-bodies in the city for mapping of schistosomiasis infection sites and transmission foci are recommended to enable immediate control measures before the situation gets out of control.

Decline of urinary schistosomiasis in Kurmuk town, western Ethio-Sudanese border, Ethiopia.

Urine examination of the residents of Kurmuk town, Western Ethio-Sudanese border, done in April 1993, showed that Schistosoma haematobium infection has now declined to 5.7% from 30.2% in 1981. The current intensity of infection is also as low as 20 eggs/10 ml urine. However, the finding of infected Bulinus africanus indicates resurgence of urinary schistosomiasis in the town. Possible factors that may have contributed to the decline and measures required to contain the disease are discussed.

Amoebiasis in Ethiopia.

In a countrywide survey of amoebiasis, a total of 12,457 persons in 97 communities was stool examined by formol-ether concentration technique. The overall prevalences of Entamoeba histolytica infections, as measured by rate of cyst-passers, in schoolchildren and non-school communities were 15.0% and 3.5%, respectively. Slightly more females (18.4%) than males (14.2%) were infected among schoolchildren (p < 0.05) but the difference was not significant among non-school communities (p > 0.05). There was a tendency but not a statistically significant decline of cyst-excretion with increasing age. So far as our survey goes, the influence of altitude on the prevalence of amoebiasis appeared not to be significant. Health education, improvement of sanitation and personal hygiene are suggested as realistic measures to reduce the transmission of this parasite.

Variability of egg excretion in Schistosoma mansoni infection in Ethiopia: a case report.

An Ethiopian boy, aged 18 years, and heavily infected with S. mansoni (1250 eggs per gram of faeces), gave stool sample for microscopy three times a day (at 9:00 am, 1:00 pm and 4:00 pm) for 5 consecutive days. Each time two slides were prepared by the modified Kato's thick-smear technique. The maximum egg count at each examination was converted to eggs per gram of faeces (EPG). There was no significant variability (at 10% level, F-value = 0.04) in in egg counts made at different times of the day. However, the coefficient of variations between the egg counts made on different days were fairly high ranging from nearly 61% to 73% and the differences being highly significant at 10% level (F value = 4.076). The implications of this day-to-day variability of S. mansoni faecal excretion in "selected" chemotherapy in Ethiopia is discussed.

Intestinal helminthic infections in the southern Rift Valley of Ethiopia with special reference to schistosomiasis.

Nineteen communities located in the southern part of the Ethiopian Rift Valley were surveyed for S. mansoni infection and other helminth parasites of man. S. mansoni infected individuals were recorded in 11 communities and human prevalence reached more than 10% in 4 of them. The snail intermediate hosts were Biomphalaria pfeifferi in the lower Omo River basin and B. sudanica in the Rift Valley lakes. Other parasites encountered included A. lumbricoides (11.2%), T. trichiura (10.3%), hookworms (25.3%), Taenia sp. (8.1%), Strongyloides sp. (2.9%), H. nana (0.8%), Trichostrongylus sp (0.3%) F. hepatica (0.1%) and E. vermicularis (0.1%). In some communities the prevalence of hookworms, A. lumbricoides and T. trichiura reached 70%, 66.6% and 60%, respectively. A strong association (r = 0.9) was observed between altitude and parasite prevalence and burden. In nine communities located below 1200 metres, infected individuals harboured nearly two or less the number of parasite species while in 10 communities located at altitude above 1200 metres, multiple infection with three or more parasites reached as high as 53.2%. Similarly, the average parasite species per infected person ranged from 0 to 1.4 in the nine communities located at lower altitudes and from 1% to 2.6% in the 10 communities located at higher altitudes. By ages, both prevalence and multiparasitism are significantly in favour of those below 20 years of age (P < 0.005) although hookworms are prevalent in a wider age range. The widespread occurrence of intestinal schistosomiasis in the southern Rift Valley and the epidemiological pattern of other intestinal helminth parasites of man in this section of the Valley are discussed.

Evaluation of reagent strips for detection of Schistosoma haematobium infection in the lower Awash valley, Ethiopia.

The use of reagent strips as indirect morbidity indicators in Schistosoma haematobium infection has been assessed in comparison with urine filtration technique in the lower Awash valley of Ethiopia in 1991. The prevalence of infection by reagent sticks and urine filtration was 16.0% and 3.6%, respectively. Reagent stick haematuria was highly related with urine filtration at the 2+ limit rather than the 1+ limit. A strong association was also obtained between prevalence rate and intensity of infection of all children at both haematuria limits. The prevalence of haematuria was not sex-related but there was age-associated infection and the prevalence was highest in the 10-13 year age group. The possible use of reagent stick haematuria in the monitoring of S. haematobium infection in Ethiopia is discussed.

A preliminary survey for intestinal parasites in the Tis Abay town, northwest Ethiopia, with special references to Schistosoma mansoni.

A parasitological survey was made in Tis Abay town, north western Ethiopia in January 1991. A total of 615 stool specimens were randomly collected from school and non-school populations. Prevalence rates for S. mansoni and other intestinal helminths were computed. Human behaviour and waste disposal were observed to be conducive for transmission of schistosomiasis and soil-transmitted parasites. From the findings of this preliminary survey it is suggested that improvement of sanitary conditions and provision of a piped water supply to all households may reduce transmission of soil and water-borne infections.