Mosquito species diversity and abundance in relation to riceland agroecosystem and filarial infection in Kafr El-Sheikh Governorate, Egypt

The present work studied the mosquitoes abundance, identification, distribution and density in three villages [rural area] and one city [urban area] in Kafr El-Sheikh Governorate namely; Kebreet, Minyat Al-Ashraaf, El-Salmia and Fowa city, respectively during the rice cultivation season in relation to filaria from June to Oct. 2009. A total of 11381 mosquitoes larvae belonging to four genera and 8 species were collected. Of which 3525 [31.0%] in Minyat Al-Ashraaf followed by 3339 [29.3%] in Kebreet, 3331 [29.3%] in El-Salmia villages compared with 1186 [10.4%] in Fowa city. The five most common species collected during this study were Culex pipiens [39.2%], Cx. antennatus [27.3%], Cx. univittatus [15.8%], Anopheles pharoensis [10.4%], and An. coustani[3.8%]. The mosquito species diversity [H] and evenness [EH] in the [rice cultivated areas] Minyat Al-Ashraf, Kebreet and El-Salmia villages [H = 1.286, EH= 0.829; H= 1.227, EH= 0.742; H= 1.110, EH=0.882; respectively] were much higher than in the Fowa city [non rice cultivated area] [H= 0.718, EH= 0.608]. On the other hand, the highest diversity and density of adult mosquitoes species obtained from Minyat Al-Ashraaf were 5 species and [33.8%], followed by Kebreet 5 species and [31.6%], El-Salmia 4 species and [24.5%], respectively compared with 3 species and [10.1%] in Fowa city. Cx. pipiens adults were the predominant species, in all filarial indicator areas [68.1, 53.4, 40.8 and 20.8 mosquitoes/room] in Minyat Al-Ashraaf, Kebreet, El-Salmia villages and Fowa city, respectively. Cx. pipiens was the only species to cany infective larvae as well as other stages, while Cx. antennatus carried immature stages only [not infective]. Filarial larvae in Cx. pipiens and Cx. antennatus were found only in Minyat Al-Ashraaf and Kebreet villages. It is inferred from the data that different levels of habitat with regard to rice cultivation have different effects on mosquito diversity and abundance. Also, our study revealed that filarial vectors Cx pipiens and Cx. antennatus had a wide distribution and high relative density especially in irrigated rice regions and hence its role in disease transmission in Kafr El-Sheikh region needs further investigation

Field evaluation of repellency effect of some plant extracts against mosquitoes in Egypt

Sixteen ethanolic and petroleum ether extracts of 4 indigenous plants namely Echinochloa stagninum [Gramineae], Phragmites austra-lis [Poaceae], Avicennia marina [Avicenniaceae] and Artemisia monosperma [Compositae], were evaluated on human volunteers, and compared with off [Deet or N.N.diethyl toulamide], a commercial plant-based repellent against wild mosquitoes in Tanbol District about 15 km north to El-Mansoura city. The repellent action of the plant extracts tested varied depending on the plant species, part, solvent used in extraction and the extract dose. The petroleum ether extraction of was more effective in exhibiting the repellent action against the mosquito as compared with ethanolic extraction. At the lowest concentration [5%], complete protection was attained by petroleum ether extracts of Ar. monosperma leaves and A. marina fruits 4h and lh post-application, respectively. While the A. marina fruits, Ar. moih nna stems extracts and off showed significantly less repellency [P <0.01] [95.7, 80.8 and 78.9%; respectively] after 4h from treatment. A. monosperma leaves especially proved potential candidate for use in developing commercial repellents as an alternative to conventional synthetic chemicals, particularly in community vector control applications