Asunto(s)
Sistemas Prepagos de Salud/economía , Indigencia Médica , Adulto , Comportamiento del Consumidor/estadística & datos numéricos , Control de Costos/métodos , Eficiencia , Servicio de Urgencia en Hospital/estadística & datos numéricos , Estudios de Evaluación como Asunto , Sistemas Prepagos de Salud/estadística & datos numéricos , Accesibilidad a los Servicios de Salud/estadística & datos numéricos , Mal Uso de los Servicios de Salud/economía , Humanos , Masculino , Modelos Teóricos , Evaluación de Programas y Proyectos de Salud/métodos , Reembolso de Incentivo , Gobierno Estatal , Encuestas y Cuestionarios , WisconsinRESUMEN
Schistosoma haematobium miracidia were detected in sentinel snails placed in 16 human water contact sites in the Volta Lake, each month from March 1973 to November 1977. Results showed that rates of infection were seasonal, and that infected snails were more often found in water contact sites sheltered by emergent plant growth than in exposed open beach sites with no emergent vegetation. Sentinel snail infection rates were correlated with natural snail infection rates and with epidemiological levels of schistosomiasis in village inhabitants. After two years of chemotherapy and mollusciciding, levels of disease and sentinel snail infection rates dropped in two-thirds of the villages. In the remaining villages, however, the sentinel snail infection rates were not correlated with the fall in epidemiological level, because of ecological changes in the water contact sites.It is concluded that, unless control measures are continued, the constant changes in the lake shore environment will lead to a rapid re-establishment of previous levels of disease transmission.
Asunto(s)
Schistosoma haematobium/fisiología , Esquistosomiasis/transmisión , Animales , Ghana , Humanos , Larva/fisiología , Caracoles/parasitologíaRESUMEN
Bulinus truncatus rohlfsi is the intermediate host of urinary schistosomiasis, which is highly endemic in the man-made Volta Lake. In 1971, a WHO/UNDP schistosomiasis project was established in the Pawmpawm branch and part of the Afram branch of Volta Lake. Malacological findings of the preliminary phase indicated that the snails were distributed in the littoral zone of the lake, and that this distribution was correlated with the presence of vegetation, especially Ceratophyllum. Transmission nearly always occurred in "water contact sites", i.e., places where people come into contact with water.A snail-sampling technique with palm-leaf mats was developed and standardized after it had been shown in sensitivity trials to compare favourably with a modified version of the "man-time" sampling method, in which the number of snails collected per man-hour is recorded. It is recommended that both these methods should be used to conduct ecological studies of B. rohlfsi in water contact sites.