RESUMEN
Anopheles mascarensis has been demonstrated to be a vector of human malaria in the East coast of Madagascar. Here, we present original data obtained from 1996 to 2003 on the distribution, biology and vectorial capacity of An. mascarensis in the Middle-West of Madagascar. This species is consistently exophilic both for its trophic and resting behaviour. This accounts for the absence of clear impact of any indoor insecticide spraying. This species is mainly zoophilic, but can occasionally bite humans, which explains a low sporozoitic index (1/2218 = 0.045%). The densities of human landing mosquitoes are most of the time very low, with the exception of a peak between May and August at the beginning of the dry season. It implies that the vector's efficiency is very low but not insignificant in the Middle-West of Madagascar, a situation opposite to what is observed on the East coast. The vectorial efficiency of An. mascarensis and An. arabiensis would enable to maintain a low malarial endemicity in the Middle-West, even in the complete absence of An. funestus.
Asunto(s)
Anopheles/parasitología , Enfermedades Endémicas/estadística & datos numéricos , Insectos Vectores/parasitología , Malaria/epidemiología , Altitud , Animales , Anopheles/clasificación , Anopheles/patogenicidad , Anopheles/fisiología , Clima , Ensayo de Inmunoadsorción Enzimática , Conducta Alimentaria/fisiología , Humanos , Insectos Vectores/clasificación , Insectos Vectores/patogenicidad , Insectos Vectores/fisiología , Longevidad , Estudios Longitudinales , Madagascar/epidemiología , Malaria/parasitología , Malaria/prevención & control , Malaria/transmisión , Control de Mosquitos , Densidad de Población , Vigilancia de la Población , Características de la Residencia , Estaciones del AñoRESUMEN
Fluorescent pteridines are photosensitive pigments of mosquito cuticle. Their quantity decreases with time during the adult life of mosquitoes. In order to test the feasibility of the reversed-phase HPLC (High Pressure Liquid Chromatography) technique, to measure pteridine fluorescence and to estimate the calendar age, reared Anopheles gambiae of known age are used. Head and thorax were studied on mosquitoes aged 0, 5, 10, 20 days after emergence. There was significant difference between male and female of 0 and 5 days of age; the difference was not significant at 10 days of age. The level of fluorescence between a female's head and thorax non separated does not differ from the sum of fluorescence level of separated head and thorax. Pteridin fluorescent of female's head and thorax does not correlate. It decreases significantly with chronological age between 0 and 5 days either for head + thorax or for head alone. Conversely, this fluorescence quantity is weak and maintained constant beyond 5 days. The use of thorax alone of the female mosquito allows the differentiation of mosquito aged less than 5 days, between 5 and 10 days and aged more than 10 days. Reversed-phase HPLC technique, at least in the way we have demonstrated, does not appear sensitive enough to estimate the age of the species An. gambiae reared in an insectarium. It seems that this technique, relatively complex to manage, does not bring a substantial advantage compared to the method of Detinova, which allows the separation of nulliparous and parous females (i.e. < or = 3 days versus > 3 days).
Asunto(s)
Anopheles/crecimiento & desarrollo , Cromatografía Líquida de Alta Presión/métodos , Colorantes Fluorescentes/normas , Insectos Vectores/crecimiento & desarrollo , Pteridinas/normas , Factores de Edad , Animales , Anopheles/clasificación , Cromatografía Líquida de Alta Presión/normas , Estudios de Factibilidad , Femenino , Cabeza/crecimiento & desarrollo , Humanos , Insectos Vectores/clasificación , Masculino , Paridad , Caracteres Sexuales , Tórax/crecimiento & desarrollo , Factores de TiempoRESUMEN
Ticks are traditionally considered being host-specific parasites. The pattern of tick-host relationship was elucidated by exhaustive collection from a considerable number of potential hosts from numerous sites in the Malagasy mid-altitude forest. It can from the findings be concluded that the Malagasy ticks found on small mammals may be distinguished as either having a broad host-specificity or being highly host-specific. The results may provide important information in respect to phylogenetic studies with regards to the geological history of Madagascar and its endemic fauna.
Asunto(s)
Vectores Arácnidos/fisiología , Interacciones Huésped-Parásitos/fisiología , Ixodes/fisiología , Control de Ácaros y Garrapatas/métodos , Altitud , Animales , Vectores Arácnidos/microbiología , Vectores Arácnidos/parasitología , Enfermedades Endémicas/estadística & datos numéricos , Ixodes/microbiología , Ixodes/parasitología , Madagascar , Mamíferos/fisiología , Filogenia , Vigilancia de la Población , Muestreo , Especificidad de la EspecieRESUMEN
"Tick - host specificity. Results of an intense sampling study in Madagascar"" : Ticks are traditionally considered being host-specific parasites. The pattern of tick-host relationship was elucidated by exhaustive collection from a considerable number of potential hosts from numerous sites in the Malagasy mid-altitude forest. It can from the findings be concluded that the Malagasy ticks found on small mammals may be distinguished as either having a broad host-specificity or being highly host-specific. The results may provide important information in respect to phylogenetic studies with regards to the geological history of Madagascar and its endemic fauna."