The use of questionnaires for the identification of high risk areas for urinary schistosomiasis: the Ethiopian experience.

The applicability and usefulness of questionnaires directed at school children and teachers and routed through the usual administrative/educational system for the identification of communities at risk for urinary schistosomiasis in Ethiopia was assessed in the Awash Valley in 1992 as part of a multi-country study. Pre-tested questionnaires were distributed to 28 elementary schools. A total of 2918 children and 56 teachers completed the questionnaires. Teachers and the biomedical team tested 2662 and 2602 children by reagent strips in 24 schools. The prevalences of children with questionnaire positive (yes) answers for indicators of urinary schistosomiasis, "blood in urine" and "schistosomiasis" or "pain when urinating", were 4.1%, 3.6% and 11.2%, respectively. The median rank given by teachers for "blood in urine" and "schistosomiasis" from among a list of symptoms/diseases that were affecting children in the area was 7 (not cited by the respondent). The prevalence of haematuria at the 1+ limit by teacher and biomedical team reagent testing was 21.9% and 17.5%, respectively. Prevalence of urinary schistosomiasis among the children tested by urine filtration was 2.7%. The relation between children's and teachers's questionnaire answers for the markers of urinary schistosomiasis, on the one hand, and between children's questionnaire answers and teacher stick testing results, on the other, gave no significant correlation. Conventional parasitological testing required US+ 226 per screened school as opposed to US+ 47 and US+ 153 for questionnaires and teacher testing, respectively. The approach worked well operationally and was cheaper. Nevertheless, it did not serve its diagnostic purpose in the Awash Valley. This is explained, among others, by the low prevalence of urinary schistosomiasis in the study area which probably resulted in low perception of the disease by the immigrant population from the highlands who constituted the majority of the study population. However, as the feasibility and the cost-effectiveness of questionnaires for large-scale screening provide many possibilities in the frame of a PHC approach to disease control, a similar investigation should be carried out in a different urinary schistosomiasis endemic area before sound conclusion is given as to the diagnostic capability of the approach.

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.

The use of reagent strips for detection of urinary schistosomiasis infection in the middle Awash Valley, Ethiopia.

Reagent strip test was carried out to detect haematuria in urinary schistosomiasis infection in ten schools (1114 children) in the middle Awash Valley, Ethiopia. In five schools (557 children), were compared with results of urine filtration technique conducted simultaneously. The prevalence of infection by reagent sticks and urine filtration was 19.5% and 3.1%, respectively. Haematuria, detected by the reagent strip, was highly related with the results of urine filtration at the 2+ limit rather than the 1+ limit. However, the intensity of infection of all children was highly associated with prevalence rate at both haematuria limits. The possible use of reagent strips in Ethiopia to monitor morbidity (haematuria) due to S. haematobium infection 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.

Schistosoma haematobium infection among Ethiopian prisoners of war (1977-1988) returning from Somalia.

Fifty Ethiopian male prisoners of war aged 20-34 years returning from Somalia were examined at the Schistosomiasis Diagnostic Laboratory of the Institute of Pathobiology, Addis Abeba University, Addis Abeba in 1988. Medical history was obtained and their urine was examined by the filtration technique. Recovered eggs of S. haematobium were allowed to hatch as a test for viability. Positive patients were treated with praziquantel at a single dose of 40mg per kg. 94% of the prisoners gave history of haematuria and 96% gave history of treatment for schistosomiasis while in Somalia. S. haematobium egg positivity rate was 30% and all but one patient had viable eggs in their urine. The geometric mean egg count per 10ml urine was only 6.4. Urine examination of treated cases six weeks later showed 100% cure rate. A preliminary compatibility study between Ethiopian Bulinus snails and the Somalian strain of S. haematobium showed that B. abyssinicus and B. truncatus were susceptible to the parasite while B. africanus was only partially susceptible. The possibility that a foreign strain of S. haematobium may be introduced into ecologically and malacologically receptive areas in Ethiopia is 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.

Antimalarial drug utilization by women in Ethiopia: a knowledge-attitudes-practice study.

A survey was undertaken between December 1991 and February 1992 to assess the knowledge, attitudes, and practices with respect to malaria of 300 women from six randomly selected rural communities in central Ethiopia. A total of 85% were able to recognize one or more of the common symptoms of the disease; however, the modes of transmission were generally misunderstood and only 23% believed that transmission could be prevented. More women preferred to obtain antimalarials from government clinics rather than from private drug shops, mission clinics, unofficial suppliers of injections, open markets, or from leftover sources. Under-5-year-olds were identified as the most malaria-vulnerable group and given priority for treatment; severity of illness was the principal determinant in seeking treatment. Decisions about treatment were generally made jointly by both parents. Knowledge about the transmissibility of malaria decreased with increasing distance from a health unit (odds ratio: 0.48; 95% confidence interval: 0.27, 0.86). A logistic regression analysis indicated that literacy and village were the most important variables associated with knowledge about preventing malaria.

PIP: Malaria is the most important cause of fever and morbidity in the tropics and is a significant source of mortality, especially among infants and young children. It remains one of the top ten leading causes of morbidity and mortality in Ethiopia. The resistance of the anopheline mosquito vectors and of the Plasmodium falciparum parasites is the major obstacle to the control of malaria. Preventing the foci of resistant falciparum malaria from widening requires the rational use of antimalarials and the intensification of vector control. The use and misuse of antimalarial drugs has, however, been largely neglected. The authors conducted a survey between December 1991 and February 1992 to assess the knowledge, attitudes, and practices with respect to malaria of 300 women from six randomly selected rural communities in central Ethiopia. Most participants were aged 30-44 years in the range of 17-60, and 90.3% were married. 98% of the spouses were farmers and only 16.7% of the women could read or write. 85% were able to recognize one or more of the common symptoms of malaria, but the modes of transmission were generally misunderstood and only 23% believed that transmission could be prevented. More women preferred to obtain antimalarials from government clinics instead of from private drug shops, mission clinics, unofficial suppliers of injections, open markets, or from leftover sources. The women identified under-five year olds as the group most vulnerable to malaria and gave them priority treatment. Severity of illness was the principal determinant in seeking treatment, with decisions about treatment generally made jointly by both parents. Knowledge about the transmissibility of malaria decreased with increasing distance from a health unit, while literacy and village were the most important variables associated with knowledge about preventing malaria.

Schistosomiasis in the Finchaa River Valley, Wellega Region, western Ethiopia

Parasitological and malacological surveys were carried out in the Finchaa Valley; Wallega Region; Western Ethiopia. Stool examination of 960 persons in the 10 communities surveyed showed an average human prevalence of 12.4 per cent for Schistosoma mansoni. Infected individuals were present in 6 communities; but prevalence was greater than 10 per cent in only three of them; reaching 40 per cent among school children in one community. In endemic localities; the intensity of infection in terms of eggs per gram of faeces were 200 and 199 among school children and farm labours respectively. The age specific prevalence and intensity of infection were highest among the 5-14 year age group. The intermediate host of S. mansoni; Biomphalaria pfeifferi were collected from three sites; but transmission was identified at only one site located in the lower portion of the valley. Bulinus truncatus; the potential intermediate host of S. haematobium in Ethiopia; was also present in the area. The occurrence of infected human subjects and snail intermediate host confirm that Schistosoma mansoni is well established in the valley; particularly in the lower portion where a large irrigation development is under way. In this report; the threat posed by the S. mansoni and S. haematobium is discussed and the preventive/control measures to be taken are suggested

The incidence of schistosomiasis in Bahir-Dar; Ethiopia

A study was made in Bahir-Dar; North-Western Ethiopia; for a period of twelve months; to determine the incidence of Schistosomiasis mansoni. All children aged 10 years and younger in Dil Chibo and Teyima Elementary Schools were stool-examined by the formol-ether concentration technique at the beginning of the study to select schistosomiasis mansoni negative children for a later incidence study. Accordingly; 139 children in Dil Chibo and 104 children in Teyima were found negative and used for an incidence study. In the incidence surveys; the stool specimens were examined by the Kato method. The overall annual incidence rates for Dil Chibo and Teyima school children were 194/1000 and 382/1000 respectively. The rates obtained at the second survey were higher than the rates obtained at the first survey; 164/1000 and 36/1000; respectively; for Dil Chibo and 292/1000 and 77/1000; respectively; for Teyima schools. Males had a higher schistosomiasis incidence than females (P0.01). The incidence also appeared to vary with age. The value of incidence as a measure of transmission is discussed

Intestinal helminth infections at Zeghie; Ethiopia; with emphasis on schistosomiasis mansoni

A total of 460 stool specimens were examined by Kato thick smear technique to determine the prevalence of schistosomiasis mansoni and other helminth infections among people living in Zeghie town; Northwest Ethiopia. The most prevalent infections were schistosomiasis; ascariasis; and trichuriasis. The infection rates among school children for Schistosoma mansoni; Ascaris lumbricoides and Trichuris triciura were 69.7 per cent; 77.7 per cent and 64.7 per cent; respectively. The respective infection rates of these helminths among the residents were 53.1 per cent; 60.6 per cent and 50 per cent. The prevalence of schistosomiasis appeared to be higher for males than for females. The high prevalence of infection observed for these helminths in the present study clearly indicates the need for timely control measures

Transmission of schistosoma mansoni in three ecological settings in Ethiopia : epidemiological aspects

The epidemiological indices of Schistosoma mansoni for three communities in Ethiopia; Jigga (Northwest); Metahara sugar estate (Southeast) and Lake Zway (Central); each representing the three major transmission ecologies in the country; the stream; irrigation scheme and lake; respectively were studied and compared. A total of 2897 people (913; 1614 and 370 from the stream; irrigation scheme and lake; respectively) was examined for S. mansoni ova by the Kato's smear method. The highest human prevalence (58 per cent) and intensity of infection (geometric mean of 450 EPG) were recorded for the lake ecology; whereas the irrigation scheme and stream showed moderate (218 EPG) and light (172 EPG) intensities of infection; despite fairly high disease prevalences of 20 per cent and 41 per cent respectively. Age-specific analysis of prevalence; intensity of infection and relative index of potential contamination (RIPC) indicated that children in their second decade of life to be most responsible. Nevertheless; the decline of all indices with increasing age was less obvious in the lake area than others. The disparity between prevalence and intensity of infection and their implication in disease control tactics are discussed

Transmission of intestinal schistosomiasis in Bahir Dar, northwest Ethiopia.

Parasitological, malacological and transmission studies were made for a period of one year in the town of Bahir Dar, northwest Ethiopia. The overall prevalence of schistosomiasis mansoni in residents of Kebeles 8, 9 and 10 was 12%. The prevalence in Sertse Dengel school children was 45% and that in Dil Chibo school children was 32%. The peak prevalence in both sexes in school and non-school populations occurred in the age group 10-14 years. Intensity of infection showed a similar pattern of age variation as prevalence. Biomphalaria pfeifferi snail density peaked towards the end of the rainy season (September) in Lake Tana and around the middle of the dry season (January) on the shore of the River Abay. In September, infected snails were recovered from all collection sites. Of mice immersed in four water contact sites in September, schistosome infections developed in those immersed in three sites. Parasitological findings suggested that schistosomiasis infection rates depended on age and sex of individuals and geographical location of the place from the potentially infective water bodies. Snail population density and associated schistosomal infection in a human population depended on rainfall and associated ecological changes such as fluctuation in water level and vegetation density. As malacological findings and sentinel mouse immersion results indicated, it appeared that the main transmission season in Lake Tana region is towards the end of the rainy season although low level intermittent transmission may take place throughout the year.

Schistosomiasis in Ethiopia.

The literature on schistosomiasis in Ethiopia is reviewed with the objective of bringing together in one paper diverse sources which may not be available to those interested in schistosomiasis. Particular attention is given to the influence of altitude and climate, snail ecology and government economic programs on the distribution of schistosomiasis. Out of 365 communities studied between 1961 and 1986 for Schistosomiasis mansoni, cases were reported from 225 (62%), and in 85 (23%) the prevalence ranged from 10 to 92%. Most transmission sites and S. mansoni infections are in agricultural communities along streams between 1300 and 2000 m altitude infested with Biomphalaria pfeifferi, the major snail intermediate host. S. mansoni transmission above 2200 m and below 800 m is precluded in many parts of Ethiopia by low and high water temperatures, respectively. Schistosomiasis haematobium cases have been reported from 30 of the 54 communities studied, 17 of them with infection rates between 14 and 75%. Endemic S. haematobium appears to be confined in its distribution to lowlands below 800 m altitude. The highly focal distribution of S. haematobium transmission is largely due to the nonsusceptibility of most bulinine snails to the Ethiopian strain of the parasite and low water temperatures in the highlands. Water resources development, resettlement programs, refugee migration and other population movements may result in the spread of endemic S. mansoni. Lack of information on snail host/parasite relationships and the ecology of proven and suspected snail hosts does not permit predictions on the spread of endemic S. haematobium. Past and present schistosomiasis control programs in Ethiopia are reviewed and recommendations made for the national control program.