RESUMEN
Urinary schistosomiasis remains a significant burden for Africa and the Middle East. The success of population-based control programs will depend on their impact, over many years, on Schistosoma haematobium reinfection and associated disease. In a multi-year (1984-1992) control program in Kenya, we examined risk for S. haematobium reinfection and late disease during and after annual school-based treatment. In this setting, long-term risk of new infection was independently associated with location, age, hematuria, and incomplete treatment, but not with sex or frequency of water contact. Thus, very local environmental features and age-related factors played an important role in S. haematobium transmission, such that population-based control programs should optimally tailor their efforts to local conditions on a village-by-village basis. In 2001-2002, the late benefits of earlier participation in school-based antischistosomal therapy were estimated in a cohort of formerly-treated adult residents compared to never-treated adults from the same villages. Among age-matched subjects, current infection prevalence was lower among those who had received remote therapy. In addition, prevalence of bladder abnormality was lower in the treated group, who were free of severe bladder disease. Treatment of affected adults resulted in rapid resolution of infection and any detectable bladder abnormalities. We conclude that continued treatment into adulthood, as well as efforts at long-term prevention of infection (transmission control) are necessary to achieve optimal morbidity control in affected communities.
Asunto(s)
Adolescente , Animales , Niño , Preescolar , Femenino , Humanos , Masculino , Servicios de Salud Escolar , Esquistosomiasis Urinaria/tratamiento farmacológico , Esquistosomicidas/uso terapéutico , Kenia/epidemiología , Prevalencia , Factores de Riesgo , Esquistosomiasis Urinaria/epidemiología , Esquistosomiasis Urinaria/prevención & controlRESUMEN
To improve health education within primary schools, the health education booklet Juma na kichocho was evaluated during a study within 5 schools using key-informant questionnaires that recorded children's knowledge and attitude (KA) towards schistosomiasis before and after daily structured-use of booklets. A total of 229 schoolchildren (114 boys : 115 girls) of between 11 and 15 years of age were interviewed and re-assessed after a working school week. Existing and putative booklet-induced changes in KA scores for schistosomiasis were compared directly against equivalent KA scores for malaria. In total 47.4 percent of children were already aware that schistosomiasis was a water-borne disease while only 10.5 percent knew of its exact aetiology; after booklet intervention these levels increased to 54.6 and 15.7 percent, respectively. The majority of children still failed, however, to realise that re-infection could take place soon after treatment. While a positive increase was observed for children's total KA questionnaire scores for both malaria and schistosomiasis after booklet intervention, these were not statistically significant. In the context of control, further educational efforts are needed to promote and guide behavioural change, especially in relation to reduction of environmental water contact.
Asunto(s)
Adolescente , Niño , Femenino , Humanos , Masculino , Agua Dulce/parasitología , Conocimientos, Actitudes y Práctica en Salud , Educación en Salud/métodos , Folletos , Servicios de Salud Escolar , Esquistosomiasis Urinaria/prevención & control , Proyectos Piloto , Encuestas y Cuestionarios , TanzaníaRESUMEN
To improve health education within primary schools, the health education booklet "Juma na kichocho" was evaluated during a study within 5 schools using key-informant questionnaires that recorded children's knowledge and attitude (KA) towards schistosomiasis before and after daily structured-use of booklets. A total of 229 schoolchildren (114 boys : 115 girls) of between 11 and 15 years of age were interviewed and re-assessed after a working school week. Existing and putative booklet-induced changes in KA scores for schistosomiasis were compared directly against equivalent KA scores for malaria. In total 47.4% of children were already aware that schistosomiasis was a water-borne disease while only 10.5% knew of its exact aetiology; after booklet intervention these levels increased to 54.6 and 15.7%, respectively. The majority of children still failed, however, to realise that re-infection could take place soon after treatment. While a positive increase was observed for children's total KA questionnaire scores for both malaria and schistosomiasis after booklet intervention, these were not statistically significant. In the context of control, further educational efforts are needed to promote and guide behavioural change, especially in relation to reduction of environmental water contact.
Asunto(s)
Agua Dulce/parasitología , Educación en Salud/métodos , Conocimientos, Actitudes y Práctica en Salud , Folletos , Esquistosomiasis Urinaria/prevención & control , Servicios de Salud Escolar , Adolescente , Niño , Femenino , Humanos , Masculino , Proyectos Piloto , Encuestas y Cuestionarios , TanzaníaRESUMEN
Urinary schistosomiasis remains a significant burden for Africa and the Middle East. The success of population-based control programs will depend on their impact, over many years, on Schistosoma haematobium reinfection and associated disease. In a multi-year (1984-1992) control program in Kenya, we examined risk for S. haematobium reinfection and late disease during and after annual school-based treatment. In this setting, long-term risk of new infection was independently associated with location, age, hematuria, and incomplete treatment, but not with sex or frequency of water contact. Thus, very local environmental features and age-related factors played an important role in S. haematobium transmission, such that population-based control programs should optimally tailor their efforts to local conditions on a village-by-village basis. In 2001-2002, the late benefits of earlier participation in school-based antischistosomal therapy were estimated in a cohort of formerly-treated adult residents compared to never-treated adults from the same villages. Among age-matched subjects, current infection prevalence was lower among those who had received remote therapy. In addition, prevalence of bladder abnormality was lower in the treated group, who were free of severe bladder disease. Treatment of affected adults resulted in rapid resolution of infection and any detectable bladder abnormalities. We conclude that continued treatment into adulthood, as well as efforts at long-term prevention of infection (transmission control) are necessary to achieve optimal morbidity control in affected communities.
Asunto(s)
Esquistosomiasis Urinaria/tratamiento farmacológico , Esquistosomicidas/uso terapéutico , Servicios de Salud Escolar , Adolescente , Animales , Niño , Preescolar , Femenino , Humanos , Kenia/epidemiología , Masculino , Prevalencia , Factores de Riesgo , Esquistosomiasis Urinaria/epidemiología , Esquistosomiasis Urinaria/prevención & controlRESUMEN
The present study describes the action of the latex of Euphorbia splendens var. hislopii (E. milli) on species of the genus Bulinus and on Biomphalaria pfeifferi, intermediate hosts of schistosomiasis in Africa, and the Brazilian snails B. glabrata, B. tenagophila, and B. straminea, intermediate hosts of schistosomiasis in Brazil. The impact of the latex on the egg masses and embryos of B. glabrata was also evaluated. Using the standardized methodology of the World Health Organization for testing plant-derived molluscicides, we obtained a 90% lethal dose (LD90) ranging from 0.13 ppm for B. glabrata subjected to lyophilized latex to 4.0 ppm for B. pfeifferi tested with the natural latex. This material has proved to be one of the most potent and specific plant molluscicides discovered thus far, presenting advantages in terms of application so that it could be used in programs involving community participation in endemic areas in both Brazil and Africa.
Asunto(s)
Bulinus/efectos de los fármacos , Bulinus/parasitología , Euphorbiaceae , Látex/farmacología , Extractos Vegetales/farmacología , Esquistosomiasis Urinaria/transmisión , Esquistosomiasis mansoni/transmisión , Animales , Bioensayo , Diterpenos/farmacología , Embrión no Mamífero/efectos de los fármacos , Oocitos/efectos de los fármacos , Esquistosomiasis Urinaria/prevención & control , Esquistosomiasis mansoni/prevención & controlRESUMEN
A detailed knowledge of distribution patterns of schistosome intermediate hosts and their population dynamics and factors affecting these patterns will provide useful information about the possibilities and desirability of conducting snail control measures in various transmission situations. On the basis of various case studies the association between the occurrence of human water contacts and the presence of schistosome intermediate hosts or infections in the intermediate hosts is illustrated. Other parameters affecting snail distribution patterns and density fluctuations are discussed. It is concluded that ecological studies on the intermediate hosts are extremely relevant, either to optimally apply existing control measures or to develop alternative measures of snail control, such as ecological or biological control.
Asunto(s)
Biomphalaria , Bulinus , Vectores de Enfermedades , Esquistosomiasis/prevención & control , Animales , Biomphalaria/parasitología , Bulinus/parasitología , Reservorios de Enfermedades , Ecología , Ingeniería , Malí , Moluscocidas , Schistosoma/aislamiento & purificación , Esquistosomiasis/transmisión , Esquistosomiasis Urinaria/prevención & control , Esquistosomiasis Urinaria/transmisión , Estaciones del Año , Sudán , Contaminación del Agua , Abastecimiento de AguaRESUMEN
Severity of urinary tract morbidity increases with intensity and duration of Schistosoma haematobium infection. We assessed the ability of yearly drug therapy to control infection intensity and reduce S. haematobium-associated disease in children 5-21 years old in an endemic area of Kenya. In year I, therapy resulted in reduced prevalence (66% to 22%, P < 0.001) and intensity of S. haematobium infection (20 to 2 eggs/10 mL, urine), with corresponding reductions in the prevalence of hematuria (52% to 19%, P < 0.001). There was not, however, a significant first-year effect on prevalence of urinary tract abnormalities detected by ultrasound. Repeat therapy in years 2 and 3 resulted in significant regression of hydronephrosis and bladder abnormalities (41% to 6% prevalence, P< 0.001), and further reductions in proteinuria. Repeat age-targeted therapy was associated with decreased prevalence of infection among young children (< 5yr) entering into the target age group. Two years after discontinuation of therapy, intensity of S. haematobium infection and ultrasound abnormalities remained suppressed, but hematuria prevalence began to increase (to 33% in 1989). Reinstitution of annual therapy in 1989 and 1990 reversed this trends. We conclude that annual oral therapy provides an effective strategy for control of morbidity due to S. haematobium on population basis, both through regression of disease in treated individuals, and prevention of infection in untreated subjects
Asunto(s)
Praziquantel/uso terapéutico , Esquistosomiasis Urinaria/prevención & control , Triclorfón/uso terapéutico , Kenia , Esquistosomiasis Urinaria/tratamiento farmacológicoRESUMEN
In Egypt the "national schistosomiasis control program" was formulated to control transmission by reduction of prevalence and intensity of current infections, and thereby achieve an acceptable level of schistosomiasis disease control. The program was implemented foremost in Middle Egypt (1977) and Upper Egypt (1980), collectively extending 800 km alongside of the River Nile and accommodate about 10.5 million people. Schistosoma haematobium has been essentially the prevailing species infection in both areas. The strategy of control entailed both area-wide mollusciciding with niclosamide, and selective population chemotherapy with metrifonate. Evaluation in 1986 showed that prevalence dropped from pre-control 29.4% in Middle Egypt and 26.3% in Upper Egypt to 6% and 7.8% respectively, together with a remarkable drop of infections among children. Also mean intensity attained low levels consistent of low grade infections. It is evident therefore that in these areas where an enhancement of schistosomiasis infections had been anticipated the employment of the twofold strategy effected a state of low-prevalence/low-intensity signifying a lowered reservoir of infection and a substantial interference with the potentials of transmission.