Repellent activity of three essential oils against dengue and filarial vector mosquitoes

Cymbopogon nardus, Syzygium aromaticum, and Citrus sinensis have been well known to possess insecticidal activity. Here, we investigated the repellent activity of individual of three essential oils (C. nardus, S. aromaticum, C. sinensis) and a combination of essential oils (C. nardus + C. sinensis, C. nardus + S. aromaticum, and C. sinensis + S. aromaticum) against a dengue vector, Aedes aegypti and a filarial vector, Culex quinquefasciatus. The essential oils (1 mg) were smeared evenly on the surface of the left arm (three volunteers) and then subjected to 25 females of A. aegypti and C. quinquefasciatus in the cage. The number of landed mosquitos was observed every hour for 7 hours to determine the protection index (PI). The result showed that individuals of three essential oils and a combination of essential oils generated > 90% of PI until 7 hours of application for both mosquitos species tested. Overall, the data demonstrated that individual of three essential oils, i.e., C. nardus, S. aromaticum, C. sinensis, and various combinations of essential oils (C. nardus + C. sinensis; C. nardus + S. aromaticum; C. sinensis + S. aromaticum) are promising as repellent agents against A. aegypti and C. quinquefasciatus.

Ovicidal, larvicidal and pupicidal activity of Nelumbo nucifera Gaertn against the filarial vector Culex quinquefasciatus Say (Diptera: Culicidae)

In the current investigation, different solvent leaf extracts of Nelumbo nucifera were tested for their mosquitocidal potential against the filarial vector Culex quinquefasciatus. Further, bioactive compounds of the crude leaf extracts of N. nucifera were identified using GC-MS analysis. The benzene leaf extracts of N. nucifera showed significant egg, larval and pupal mortality at concentrations of 62.5, 125, 250 and 500 ppm, respectively. Mortality of ovicidal, larvicidal and pupicidal effect at 500 ppm at 48 h period were 89, 38 and 67 per cent with LC50 values 4.247, 6.694 and 4.975 and LC90 values 5.881, 9.628, 6.565 ppm, respectively. GC-MS profile of the leaf showed seven peaks and the major components identified as nuciferine, steporphine and mecambroline (29.40%). The study confirms N. nucifera has significant mosquitocidal effects.

Detection of Vector Mosquito of Filariasis in the Endemic Areas of Bangladesh

Background: Lymphatic Filariasis (LF), a mosquito born tropical parasitic disease, caused by Wuchereria bancrofti is not only a health but also a socio-economic problem in Bangladesh. Culex quinquefasciatus is the confirmed filarial vector in Bangladesh, so by controlling of this vector population, we can prevent this disease. To control this vector and decrease incidence of filariasis, we need to know studied mosquito’s sample in endemic areas. Aim and objectives: Aim of this study was to see mosquito population in search of vector species in the endemic zones of malaria and filarial. Then we confirmed presence of vector species at molecular level by species specific DNA fingerprinting. Methods: This cross-sectional entomological study was carried out in Hobiganj (Shatchori tea garden) and Moulvibazar district (Patrokhola and Madonmohonpur tea gardens). Mosquito was collected by paper cup with net, aspirator and torch light and vector mosquitoes were identified with stereoscopic microscope. After identification of the mosquitoes, these were stored in laboratory for analysis of the density of the vector mosquitoes in the endemic areas. Then the vector mosquitoes were identified through molecular method named Polymerase Chain Reaction (PCR). Result: 1427 female mosquitoes belonging to 28 species under 5 genera were collected from three tea gardens. Culex quinquefasciatus which is the confirmed filarial vector in Bangladesh was found high in number (20.74%) out of the total collected mosquitoes. Other mosquito’s species were found in various ratios. Then Culex quinquefasciatus vector was identified by PCR. Conclusion: As vector mosquitoes of LF are available in these tea gardens, the study concludes that these areas are highly LF endemic areas of Bangladesh. Through molecular method, the vector of LF can be identified certainly. As we identify the vector mosquito, thus we can prevent this LF disease at very early stage. So, these findings will be very beneficial and cost effective for a developing country like Bangladesh.

Biting Behaviour of The Filarial Vector Mosquito, Culex quinquefasciatus Say,in an Urban Area

Mosquitoes depend on blood meal for the development of their eggs into offsprings. By knowing the biting behaviour of mosquitoes, we may control mosquito-borne diseases and manage the mosquitoe menace successfully. The present study has been designed to study the biting behaviour of the filarial vector, Culex quinquefasciatus Say, in Madurai, Tamil Nadu, India from July to November 2006. This period was selected as mosquitoes are prevalent during this rainy season. Biting was more during September, October and November and the maximum of 28 caught/man/hour was recorded in November. It is predominantly an exophilic biter, but biting was also noticed as maximum inside the house during July in the study. The density of the biting population in the first floor was more than that of the second floor, which indicated the existence of vertical stratification in the biting behaviour of Cx quinquefasciatus.