Introduction: Opportunities to work together: intestinal helminth control and programmes to eliminate lymphatic filariasis.
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Adolescent↗
Biomedical subjects
B L Cline
Publications and source records attributed to B L Cline.
Quality control for parasitologic data.
Accuracy of data is of paramount concern for all research. The task of providing objective assurances of accuracy of parasitologic data for a large, multi-center epidemiologic research project in Egypt (Epidemiology 1, 2, 3 [EPI 1, 2, 3]) presented a unique set of challenges undertaken jointly by the Ministry of Health's Qalyub Center for Field and Applied Research with technical assistance from Tulane University (New Orleans, LA). The EPI 1, 2, 3 project was part of large bilateral research program, the Schistosomiasis Research Project, undertaken jointly by the governments of Egypt and the United States. This paper describes the nature of the quality control system developed to accomplish this task, presents results and discusses the findings.
Egypt↗
The epidemiology of schistosomiasis in Egypt: Qalyubia Governorate.
The primary objectives of this study, carried out in Qalyubia Governorate in Egypt (south-central Nile Delta), were to continue tracking historical trends of infection prevalence of Schistosoma mansoni and S. haematobium, determine whether satellites (ezbas) of mother villages differed significantly with respect to schistosomiasis transmission, and to asses schistosomiasis-induced morbidity on a population basis using ultrasonography. Our study revealed that S. haematobium has virtually disappeared from Qalyubia governorate, and that S. mansoni prevalence continues to decline slowly (17% in 1991 compared with 19% in 1990). The prevalence of intestinal schistosomiasis was actually higher in the mother villages than in the ezbas of the same villages, indicating that prevalence based on surveys of villages alone did not (at least for Qalyubia) cause underestimates of true prevalence. (A mother village is the large village in an area that includes hamlets or ezbas. In many areas, the infection rate in ezbas is significantly higher than in the larger central village.) Ultrasonographic studies revealed that less than 3% of the population had stage 2 or stage 3 periportal fibrosis, commonly associated with chronic schistosomiasis mansoni. This low level of morbidity was consistent with earlier data from Qalyubia, which also showed a low level of S. mansoni-induced morbidity in this governorate.
Adolescent↗
The epidemiology of schistosomiasis in Egypt: summary findings in nine governorates.
Health questionnaires and parasitologic examinations of urine and stool were evaluated from a stratified random sample of 89,180 individuals from 17,172 households in 251 rural communities in 9 governorates of Egypt to investigate the prevalence of, risk factors for, and changing pattern of infection with Schistosoma sp. in Egypt. A subset, every fifth household, or 18,600 subjects, had physical and ultrasound examinations to investigate the prevalence of and risk factors for morbidity. Prevalence of S. haematobium in 4 governorates in Upper Egypt in which it is endemic ranged from 4.8% to 13.7% and averaged 7.8%. The geometric mean egg count (GMEC) ranged from 7.0 to 10.0 ova/10 ml of urine and averaged 8.1. Age stratified prevalence of infection peaked at 15.7% in the 10-14-year-old age group and decreased to 3.5-5.5% in all groups more than 25 years of age. Age-stratified intensity of infection peaked at approximately 10.0 ova/10 ml of urine in the 5-14-year-old age groups and was about half that in all groups more than 25 years of age. Males had higher infection rates and ova counts than females in all age groups. Schistosoma mansoni was rare in Upper Egypt, being consequential in only Fayoum, which had a prevalence of 4.3% and an average intensity of infection of 44.0 ova/g of stool. Risk factors for S. haematobium infection were male gender, an age <21 years old, living in smaller communities, exposures to canal water; a history of, or treatment for, schistosomiasis, a history of burning micturition or blood in the urine, and reagent strip-detected hematuria or proteinuria. The more severe grades (II and III) of ultrasonography-detected periportal fibrosis (PPF) were rare (15 of 906) in these schistosomiasis haematobia-endemic governorates. Risk factors for morbidity (ultrasonography-detected urinary bladder wall lesions and/or obstructive uropathy) were similar to those for infection, with the exception that risk progressively increased with age. Subjects with active S. haematobium infections were 3 times as likely as those without active S. haematobium infections to have urinary tract morbidity. The prevalence of S. mansoni in 5 governorates in Lower Egypt, where it is endemic, ranged from 17.5% to 42.9% and averaged 36.4%. The GMEC ranged from 62.6 to 93.3 eggs/g of stool and averaged 81.3. Age-stratified prevalence of infection peaked at 48.3% in the 15-19-year-old age group, but averaged 35-45% in all groups more than 10 years of age. The intensity of infection was highest in the 10-14-year-old age group, and showed a range of 70-85 eggs/g of stool in those > or =5 years of age. Males had higher infection rates and ova counts than females in all age groups. Schistosoma haematobium was rare in these governorates; Ismailia (1.8%) had the highest infection rate. Risk factors for S. mansoni were male gender, an age >10 years old, living in smaller communities, exposures to canal water, a history of, or treatment for, schistosomiasis or blood in the stool, detection of splenomegaly by either physical examination or ultrasonography, and ultrasonography-detected PPF. The more severe grades (II and III) accounted for 463 (13.3%) of the 3,494 having ultrasonography-detected PPF. Risk factors for morbidity (ultrasonography-detected PPF) were similar to those for infection except that inhabitants of smaller communities were not at increased risk. Active S. mansoni infection increased the odds ratio (OR) of having PPF by 1.37. In comparison with others with normal-size livers, subjects having hepatic enlargement in either the midclavicular line or the midsternal line detected by physical examination or ultrasonography had a reduced risk (ORs = 0.64-0.72) of PPF. The prevalences of lesions detected by ultrasonography were 23.7% for enlargement of right lobe of the liver, 11.3% for enlargement of left hepatic lobe, 20.6% for splenomegaly, and 50.3% for PPF. Schistosoma mansoni has almost totally replaced S. haematobium in Lower E
Adolescent↗
Anthropological contributions to a community-based schistosomiasis control project in northern Cameroun.
This paper describes how anthropological contributions and extensive cooperation between tropical medicine and medical anthropology researchers contributed to a successful community-based cost recovery schistosomiasis control project in northern Cameroun. The project led to increased knowledge about urinary schistosomiasis by local people, significant decreases in prevalence and intensity of the disease, and increased utilization of primary health care centers.
Anthropology, Cultural↗
Community-based approach to schistosomiasis control.
With few exceptions, efforts to control schistosomiasis have relied upon ongoing community cooperation with "outsiders' rather than creating within the community the capacity and means for carrying out ongoing disease control measures with minimal external support. Offered as a useful model is a program in Kaele subdivision, Extreme North Province, Cameroon designed to establish and integrate within the primary health care (PHC) system the control of urinary schistosomiasis, hyperendemic in the region. At the community level, and with minimal dependence upon external resources, culturally appropriate and effective health education was instituted, the capacity to diagnose and treat schistosomiasis was created, diagnosis and drug therapy (praziquantel) was made available conveniently and at low cost, and, on a very limited basis, snails were controlled. Efforts were made to build upon and strengthen existing community structures and institutions rather than create new ones. The impact of the interventions was measured in terms of changes in knowledge and behavior, prevalence and intensity of infection, utilization of health services, and the ability to finance the control activities within the context of a generalized cost recovery system. Program successes and failures are discussed, as well as lessons learned and their implications.
Animals↗
Ivermectin distribution and the cultural context of forest onchocerciasis in South Province, Cameroon.
This investigation examined the cultural context of forest onchocerciasis in several communities in the Dja-Lobo Division of southern Cameroon. The study sought to elucidate behaviors that would enhance or diminish health status relative to forest onchocerciasis and other filarial infections, and to make culturally sensitive and appropriate recommendations regarding the development of health education materials and the long-term sustainability of the ivermectin distribution program in Dja-Lobo. The study consisted of two sequential components; the first was a qualitative study of a few severely affected villages and the second was a quantitative study of 212 randomly selected heads of households from eight villages. The Boulou and Baka peoples in these communities defined general filariasis (minak) as small worms under the skin, identified flies as important transmitters of the illness, and indicated that blindness and other skin and ocular problems were a consequence of the illness. Illness of the Dja (referring to an illness found near the Dja River) was another illness that was closely linked to onchocerciasis; local people indicated it was transmitted by the black flies found near the Dja River, resulting in severe itching and leopard skin. These and other cultural-behavioral data on filariasis were used to implement a health education and distribution program.
Antinematodal Agents↗
The slow fix: communities, research, and disease control.
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Communicable Disease Control↗
Evaluation of alternate methods of rapid assessment of endemicity of Onchocerca volvulus in communities in southern Cameroon.
Potential diagnostic indicators of onchocerciasis (subcutaneous nodules, depigmentation or leopard skin, microfilaruria, diethylcarbamazine patch test positivity, excoriations, and pruritus) were evaluated in a rain forest region of southern Cameroon for usefulness in rapid assessment of onchocerciasis endemicity in communities. Thirty-two study villages were selected, representing high, intermediate, and low prevalence levels, and 846 adult male residents of these communities 20 or more years of age were examined according to a defined protocol. Skin snips (from each iliac crest) served as the reference standard. Skin snip positivity was 75.5%; the effect of age was minimal. Leopard skin and nodules showed the strongest correlation with both the skin snip prevalence and community microfilarial load, as reflected by the adult male study population. We selected > or = 20% nodules or > or = 20% leopard skin as the most appropriate local criteria for assigning a community to high priority for control, which corresponds to a > or = 90% skin snip prevalence in adult males. While this criteria should not be applied to regions with savannah onchocerciasis, we believe the methodology can and should be used to determine appropriate diagnostic indicators for rapid assessment of Onchocerca volvulus endemicity in regions with different dynamics of transmission and clinical expression of disease.
Adult↗
The impact of control measures on urinary schistosomiasis in primary school children in northern Cameroon: a unique opportunity for controlled observations.
As part of a program to integrate schistosomiasis control into the primary health care system in northern Cameroon, an unexpected opportunity to undertake a controlled evaluation of the impact of interventions was recognized. Inadvertently, a large part of Mindjil, one of four assessment villages, had been essentially excluded from the program, creating a unique natural control. The prevalence of infection with Schistosoma hematobium in school-aged children was 7% in the areas where the control program was implemented, and 71% in the excluded areas (P < 0.0002). High intensity infection was 1% and 26% in the two areas, respectively (P < 0.0002). Children in the school where the control interventions were implemented had a significantly lower prevalence of infection with Schistosoma hematobium (P < 0.005). Subjects in intervention areas demonstrated greater knowledge about the transmission of schistosomiasis than those in the control area. This study documented and quantified program impact in a controlled manner not usually possible in field studies and also illustrated how unrecognized intracultural diversity (within culture differences) in target populations may effect disease control programs in communities.
Adolescent↗
Impact of Schistosoma haematobium infection and of praziquantel treatment on anaemia of primary school children in Bertoua, Cameroon.
There is some debate as to the extent to which Schistosoma haematobium haematuria may be the cause of anaemia. Our goal was to evaluate the impact of a single 40 mg kg-1 dose of praziquantel on anaemia. Since praziquantel does not reduce the hookworm intensity of infection (a major cause of anaemia in children in the area) changes in the prevalence of anaemia in the study population should be due only to the elimination of S. haematobium. Seven hundred and seventy-one primary schoolboys from Bertoua (East Cameroon) were divided into four groups: high infection, moderate infection treated with praziquantel or placebo, and non-infected. Haemoglobin concentrations of the children were determined at the onset of the study and 6 months after the praziquantel intervention. Mean haemoglobin concentrations were not significantly different for no infection or for mild or heavy infection by S. haematobium. A factorial analysis of variance using S. haematobium intensity of infection, malaria and intestinal parasite infections and age as independent variables and haemoglobin concentration as the dependent variable show that only age and malaria infection show a significant relationship with haemoglobin concentration. Despite treatment with praziquantel, all the children in the treatment groups had lower mean haemoglobins 6 months after intervention. A factorial analysis of variance using age, malaria infection and the treatment category as independent variables and the difference in haemoglobin concentration as the dependent variable shows that only malaria infection showed a significant relationship with haemoglobin concentration.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Albendazole in the treatment of onchocerciasis: double-blind clinical trial in Venezuela.
A double-blind clinical trial was conducted in Monagas State, Venezuela to assess the tolerance and efficacy of albendazole in the therapy of Onchocerca volvulus infection. Forty-nine patients (26 treated and 23 controls) received a 10-day course of albendazole (400 mg/day) or a placebo. Consistent with the excellent tolerance observed, albendazole did not kill microfilariae. However, analysis of changes in microfilarial densities (mf/mg of skin) over one year showed that albendazole was active against O. volvulus, presumably by interfering with embryogenesis. The nature, degree, and duration of this effect remain to be determined.
Adolescent↗
The impact of Schistosoma haematobium infection and of praziquantel treatment on the growth of primary school children in Bertoua, Cameroon.
Our objective was to determine in a Cameroonian school population the effect of mild to moderate S. haematobium infection intensity on growth and development of children before and 6 months after praziquantel treatment. Previous studies have yielded contradictory results. Children from Bertoua schools were divided into four study groups: heavily infected (> 500 eggs 10 ml-1), moderately infected (1-499 eggs 10 ml-1) treated with praziquantel, a similar group treated with placebo, and an uninfected control group. Anthropometric measures--height for age per cent median (HAPM), and weight for age per cent median (WAPM)--were significantly higher among the uninfected children. Stepwise regression analysis showed that S. haematobium and Ascaris infections were the strongest predictors of the HAPM with hookworm and malaria infections playing a lesser role. Post treatment comparison of the praziquantel treatment group and the placebo group showed no significant differences for the anthropometric indicators except for mid-arm circumference. Longer observations of growth after treatment as well as monitoring of the rate of reinfection would be necessary to understand better the effect of S. haematobium on growth.
Adolescent↗
Changes in antischistosomal drug usage patterns in rural Qalyubia, Egypt.
To investigate the usage of antischistosomal drugs in the Nile Delta, an antischistosomal drug history was obtained by interview from a sample of inhabitants of the villages of Halaba (1,024, or every 4th household) and Kharkania (505, or every 20th household), south-central Nile Delta. Only 3% and 0.4% of participants, respectively, in the 2 villages reported receiving antischistosomal drugs during the previous 4 years. Most villagers received oral compounds (praziquantel and niridazole), and the treatment regimen was completed by 95%. This study reveals changes in antischistosomal drug usage since a study 8 years earlier in the village of Halaba, when most of the drugs were injectable compounds.
Administration, Oral↗
Evaluation of UNICEF/Arab Republic of Egypt/WHO schistosomiasis Control Project in Beheira Governorate.
We evaluated the UNICEF/Government of Egypt/WHO Schistosomiasis Control project in 2 districts of Beheira Governorate of the Nile Delta during 3 weeks in February 1988. The project, begun in 1983, was focused on reducing prevalence, intensity, and morbidity due to schistosomiasis by providing diagnosis and treatment with praziquantel to schoolchildren. Schools were visited twice. Following the completion of the school surveys, the program was extended into the community. Chemotherapy was delivered by mobile and static teams. The evaluation indicated that, with respect to accuracy of diagnosis, record-keeping, and coverage of targeted populations, project tasks were performed exceedingly well by highly motivated, well-supervised mobile teams. Static teams in rural health centers were less successful in providing diagnosis and chemotherapy to village populations. We resurveyed 6 randomly selected schools to assess the impact of chemotherapy. Overall, the prevalence of Schistosoma mansoni infection was reduced from 60.3% to 24.8% between the first and second surveys (approximately 1 year apart) and was still lower (41.1%) than initial levels up to 3 years after the last treatment with praziquantel. The percentages of those with greater than or equal to 34 S. mansoni eggs/slide using the Kato-Katz technique showed a marked and prolonged decrease (17.1% to 0.3% to 2.2%). The prevalence of S. haematobium infection dropped from 37.6% to 5.5% and was still 9.9% at the time of the evaluation. The percentages of those with greater than or equal to 50 S. haematobium eggs/10 ml urine dropped less dramatically (17% to 4.4% to 11.9%). Mobile teams conducting vigorous chemotherapy programs targeted at schoolchildren can have long-lasting benefits in terms of prevalence and intensity.
Child↗
Human schistosomiasis in Cameroon. I. Distribution of schistosomiasis.
The status of schistosomiasis in Cameroon was examined in a nationwide survey of 5th grade schoolchildren. Five hundred twelve schools were surveyed; 19,524 urine and 22,166 stool samples were examined. The 3 northern provinces, which comprised 29% of the population, had 87% of all urinary and 82% of all intestinal cases. These provinces have a low seasonal rainfall. The presence of temporary bodies of water and of molluscan intermediate hosts adapted to this environment permits intense transmission of schistosomiasis haematobium and mansoni. In the rest of the country, the distribution of Schistosoma haematobium and S. mansoni was highly focal. S. intercalatum endemic areas were restricted to the equatorial forest and were small with low prevalences and intensities.
Adolescent↗
Monofilament nylon filters for preventing dracunculiasis: Durability and copepod retention after long term field use in Pakistan.
Filtration of drinking water to remove the cyclopoid copepod intermediate hosts of guinea worm. Dracunculus medinensis, is one of the primary intervention strategies for preventing dracunculiasis. In early 1987, monofilament nylon filters with 200 microns pore size were distributed to households in selected guinea worm-infected villages in Pakistan. The filters proved popular with the villagers, although reports of "loss of filters" could diminish the community-wide effectiveness of this control measure. After 12 to 15 months of usage a sample of these filters was collected and examined for damage or impairment which would decrease their use or their capacity to retain potentially infective copepods. Although all naupliar stages and early copepodids (Stages CI-II) passed through these used filters, the larger copepodids including adults (Stages CIII-VI) were retained despite small tears in the fabric. This field trial showed that after 12 to 15 months of regular use, monofilament nylon filters of 200 microns pore size remained effective in removing copepodid stages capable of supporting development of D. medinensis larvae. Considering the ease of use, popularity and effective filtration of potentially infective copepods following prolonged field use, we recommend that monofilament filters be considered in any program of guinea worm elimination.
Animals↗
1983 Nile Delta schistosomiasis survey: 48 years after Scott.
To determine whether the sharply declining Schistosoma haematobium infection rates in parts of the Nile Delta could be generalized to the entire region, and to update the status of S. mansoni infection rates, a large scale survey was undertaken in 1983 in 70 of the 71 districts of the Nile Delta. In a house-to-house survey, greater than 91% of the sample population of 16,675 participated by providing stool and/or urine specimens which were examined qualitatively by Kato thick smear and sedimentation techniques, respectively. After the 1935 survey by Scott, the prevalence of S. mansoni appeared to change little, from 33% in 1935 to 39% in 1983, but a more sensitive diagnostic technique in 1983 strongly suggested that the actual prevalence had decreased between the 2 surveys. In contrast, the prevalence of S. haematobium infection decreased from 56% to 5%, with a similar decline in all 8 governorates. The dramatic decline in S. haematobium prevalence has been accompanied temporally with a sharp decrease in the population density of Bulinus truncatus. S. mansoni has become the predominant human schistosome species in the Nile Delta.
Adolescent↗