RESUMEN
Dirofilaria immitis (Leidy 1856), a nematode parasite, is the etiologic agent of canine heartworm disease and mosquitoes are essential intermediate hosts. Mosquito susceptibility to the worms differ with species, strains and also among individuals of the same strain. To evaluate the degree of susceptibility of Rio de Janeiro laboratory raised strain of Aedes aegypti, we fed mosquitoes on canine blood with different densities of microfilariae (mf). There was no significant difference in the rate of development among the three different densities of mf. Infective larvae were found in the head and proboscis of all mosquitoes provided bloodmeals with different densities of mf after the 11th day post-infection. The infection rate of mosquitoes after ingestion of blood containing 3,000 mf/ml, 5,000 mf/ml and 7,000 mf/ml were 55.3%, 66.7% and 100%, respectively. The vector efficiency indices ranged from 1.6 to 9.3. The finding of L3 stage larvae, high infection rates and vector efficiency indices suggest that Ae. aegypti, Rio de Janeiro laboratory strain, is a potential vector of D. immitis, although of low efficiency.
Asunto(s)
Aedes/parasitología , Dirofilaria immitis/aislamiento & purificación , Insectos Vectores/parasitología , Aedes/genética , Animales , Brasil , Perros , Femenino , Insectos Vectores/genética , MasculinoRESUMEN
The identification of arthropod bloodmeals is important in many epidemiological studies, as, the understanding of the life cycle of vectors and the pathogens they transmit, as well as helping to define arthropods' control strategies. The precipitin test has been used for decades, but ELISA is slowly becoming more popular. To compare the two tests for sensitivity, specificity and accuracy to detect small insect bloodmeals, Aedes aegypti or Ae. fluviatilis mosquitoes were fed either on feline, canine or human hosts. Mosquitoes were frozen at 6, 12, 24, 48 or 72 h after feeding. Precipitin test showed better specificity and accuracy and ELISA test showed higher sensitivity. Better results with both tests were achieved when mosquitoes were frozen within 48 h from feeding.
Asunto(s)
Aedes/fisiología , Sangre , Ensayo de Inmunoadsorción Enzimática/métodos , Pruebas de Precipitina/métodos , Animales , Gatos , Criopreservación/métodos , Perros , Ingestión de Alimentos , Conducta Alimentaria , Femenino , Humanos , Sensibilidad y Especificidad , Factores de TiempoRESUMEN
Dirofilaria immitis is a widespread mosquito-borne parasite that causes dirofilariasis, a commonly diagnosed disease of dogs that is rarely reported in cats and humans. A mosquito survey was conducted in Itacoatiara in the State of Rio de Janeiro, from March 1995 to February 1996, using canine, feline and human baits. A total of 3,667 mosquitoes were dissected for D. immitis larvae, representing 19 species and 10 genera. From those, Ae. scapularis, Ae taeniorhynchus, Cx. quinquefasciatus, Cx. declarator, Cx. saltanensis and Wy. bourrouli were found infected with D. immitis parasites, and among those only the first three harbored infective larvae. The majority of larvae were found in the Malpighian tubules (889/936), and larval melanization was observed in the two Aedes species. In descending order, the best vectors were Ae. scapularis. Ae. taeniorhynchus, and Cx. quinquefasciatus which alternate seasonally in importance. Cx. quinquefasciatus is suggested to be a vector to cats. The potential transmission of D. immitis parasites by these three vectors to man is discussed.
Asunto(s)
Culicidae/parasitología , Dirofilaria immitis/aislamiento & purificación , Insectos Vectores/parasitología , Animales , Brasil , Gatos , Culicidae/clasificación , Dirofilaria immitis/crecimiento & desarrollo , Perros , Conducta Alimentaria , Femenino , Humanos , Insectos Vectores/clasificación , Estaciones del AñoRESUMEN
Heartworm, a chronic fatal mosquito-borne canine disease, is frequently diagnosed in dogs from the State of Rio de Janeiro, where its prevalence is 29.7% in the city of Niterói. Nevertheless it is rarely detected in cats (0.8%) from the same state. Dogs are the primary source of infection to mosquitoes. because cats either do not demonstrate microfilaremia or it is too low and transient for transmission. A mosquito survey was conducted in Itacoatiara, Niterói, from March 1995 to February 1996, using canine, feline and human baits. A total of 21 mosquito species (3,888 females) was collected and biting frequency was higher at dusk. The four species collected most frequently (88.9%) were: Aedes taeniorhynchus (30% of the total catch; with the peak in May/June); Culex quinquefasciatus (22.5%; August/October); Aedes scapularis (19.4%; August, October/November and January) and Culex declarator (17%; November/January). Human baits were attractive to these species and dogs were significantly more attractive to them than cats. Ae. taeniorhynchus, Cx. quinquefasciatus, Ae. scapularis, Cx. declarator and Cx. nigripalpus are the most likely mosquito species to transmit Dirofilaria immitis parasites to dogs and may transit the parasite to humans. It is also suggested that the vector to cats belongs to the games Culex.