RESUMO
Lutzomyia longipalpis is the main vector of visceral leishmaniasis in Brazil. The objective was to evaluate the effect of oil from (Azadirachta indica) neem seeds on eggs, larvae and adults of the vector. The insects were captured in the field and kept in the laboratory at ± 27 °C and 80% relative humidity. Five treatments with different concentrations were performed using two negative controls (distilled water and Tween 80) and a positive control. The eggs were sprayed with the oil at different concentrations and the number of hatched larvae evaluated for 10 days. Mortality of larvae was observed to pupation and adult mortality was observed after 24, 48, and 72 hours. Statistical analysis was performed by Tukey test at 5% probability. The highest oil concentration of eggs obtained 65.16 ± 3.24% efficacy for reducing egg hatching. The test with larvae showed 67.75 ± 2.21% efficacy at a concentration of 100 mg.mL-1. In adults, the efficacy of the 100 mg.mL-1 concentration was 96.64 ± 4.11% after 24 hours. The phytochemical analysis revealed the presence of triterpenes. These results demonstrate the potential use of this oil in the control of this vector.
Lutzomyia longipalpis é o principal vetor da Leishmaniose visceral no Brasil. O objetivo deste trabalho foi avaliar o efeito do óleo de sementes de nim (Azadirachta indica) sobre ovos, larvas e adultos do vetor. Os insetos foram capturados no campo e mantidos no laboratório a ± 27 °C e 80% de umidade relativa. Cinco tratamentos com diferentes concentrações foram realizados, usando-se dois controles negativos, um com água destilada e outro com Tween 80 (3%) e um controle positivo com cipermetrina. Os ovos foram borrifados com o óleo em diferentes concentrações e avaliou-se o número de larvas eclodidas por 10 dias consecutivos. A mortalidade das larvas foi observada até a pupação, e a mortalidade dos adultos foi observada após 24, 48, e 72 horas. A análise estatística foi feita pelo teste de Tukey a 5% de probabilidade. No teste com ovos, a maior concentração obteve 65,16 ± 3,24% de eficácia. O teste com larvas apresentou 67,75 ± 2,21% de eficácia na concentração de 100 mg.mL-1. Com adultos, a eficácia na concentração de 100 mg.mL-1 foi de 96,64 ± 4,11%, após 24 horas. A análise fitoquímica revelou a presença de triterpenos. Esses resultados demonstram o potencial uso desse óleo no controle deste vetor.
RESUMO
Phlebotomines are of medical and veterinary concern as they vector leishmaniasis, bartonellosis and some arboviruses. The adaptations of some species to places modified by humans bring these vectors into contact with dwellings, which can facilitate disease transmission, and the vector control strategies adopted have rendered controversial results. Regarding leishmaniasis, for instance, which vector and reservoirs control can be effective, there is an assumption that the incidence of human infection is directly related to the number of infectious dogs, as well as to entomological factors. Therefore, vector control can provide a cheaper and more practical solution to prevent cases of leishmaniasis. Nevertheless, due to the complexity of the factors involved, chemical control is still essential, and biological insecticides and insecticide plants, for example, represent areas for study that should be encouraged and developed since they show promising results. This paper summarizes the control strategies adopted so far, especially the methods and efficiency of the entomological components of leishmaniasis control programs.