Malaria is a major infectious disease that still affects nearly half of the world's population. Information on spatial distribution of malaria vector species is needed to improve malaria control efforts. In this study we used Maximum Entropy Model (MaxEnt) to estimate the potential distribution of Anopheles gambiae sensu lato and its siblings: Anopheles gambiae sensu stricto, and Anopheles arabiensis in Nigeria. Species occurrence data collected during the period 1900-2010 was used together with 19 bioclimatic, landuse and terrain variables. Results show that these species are currently widespread across all ecological zones. Temperature fluctuation from mean diurnal temperature range, extreme temperature and precipitation conditions, high humidity in dry season from precipitation during warm months, and land use and land cover dynamics have the greatest influence on the current seasonal distribution of the Anopheles species. MaxEnt performed statistically significantly better than random with AUC approximately 0.7 for estimation of the Anopheles species environmental suitability, distribution and variable importance. This model result can contribute to surveillance efforts and control strategies for malaria eradication.

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Dominant malaria vector species in Nigeria: Modelling potential distribution of Anopheles gambiae sensu lato and its siblings with MaxEnt

Surface water detection in the Caucasus

Pyrethroids and DDT are key insecticides in the control of malaria, yellow fever, and lymphatic filariasis vectors. Knockdown and metabolic resistance mechanisms have been proven to be important in determining the efficacy of insecticides. Here we investigated cytochrome P450 as a resistance mechanism in Anopheles gambiae Giles and Culex quinquefasciatus Say exposed to deltamethrin and DDT. Two- to three-days-old adult female mosquitoes were used for insecticide exposures and PBO synergistic assays using WHO standard guidelines, kits and test papers (DDT 4%, deltamethrin 0.05%, and PBO 4%). Polymerase chain reaction (PCR) assays were used for the identification of the species and for characterization of the kdr allele. Mortality at 24 h post-exposure was 18 and 17% in An. gambiae s.s. exposed to DDT and deltamethrin, respectively; 1 and 5% in Cx. quinquefasciatus exposed to DDT and deltamethrin respectively. Significant (P < 0.01) levels of susceptibility was recorded in mosquitoes pre-exposed to PBO, as KDT50 and 24 h of exposure ranged from 37.6 min to 663.4 min and 27 to 80%, respectively. Presence of a knockdown resistance allele was recorded in An. gambiae s.s., 22.5% for homozygote resistance and 7.5% for heterozygotes, while Cx. quinquefasciatus populations showed no kdr allele despite the high level of resistance to DDT and deltamethrin. Findings from this study indicated that cytochrome P450 mono-oxygenase expression is highly implicated in the resistance phenotype to DDT and pyrethroids in An. gambiae and Cx. quinquefasciatus in the study area.

Cytochrome P450 Mono-Oxygenase and Resistance Phenotype in DDT and Deltamethrin-Resistant Anopheles gambiae (Diptera: Culicidae) and Culex quinquefasciatus in Kosofe, Lagos, Nigeria.

Botanicals are promising bio-pesticide against the control of malaria vector since they are safe, target-specific and biodegradable. This study evaluates the larvicidal activities of Neem (Azadirachta indica) and Croton (Codiaeum variegatum) leaf extracts on the larvae of Culex mosquito under ambient laboratory conditions (28 ± 2 oC, 75 ± 5% RH, 12L: 12D photoperiod) at the Department of Biology Laboratory. Fourth instar larvae of Culex mosquito were exposed to the extracts of Neem and Croton. Concentrations of the plant extracts tested were 0%, 50%, 25%, 12.5%, 6.25%, and 3.125% at exposure periods of 6, 12, 18, 24 and 36 hours. The result of the two extracts showed significantly varying level of larvae mortality effect. Culex mosquito larvae mortality increased significantly as the concentration of the plant extract and exposure period increased. There was no survival of Culex larvae for Croton concentration of 6.25% upward at 30h exposure. However, for Neem extract, no survivor occurs only at 36h. The LC50 at 24h for Croton and Neem were 5.98g/ml (4.48 – 7.51%) and 57.32g/ml (24.72 – 89.9%) concentrations respectively. Croton showed higher mortality rate at each concentrations than Neem, thus, indicating Croton to be the most effective against Culex mosquito.

https://www.dipterajournal.com/pdf/2018/vol5issue2/PartA/5-1-23-243.pdf

Larvicidal effects of croton (Codiaeum variegatum) and Neem (Azadirachta indica) aqueous extract against Culex mosquito

Sumedang regency reported being one of dengue endemic areas in West Java. The number of dengue fever patients in Sumedang District General Hospital increased in the last quarter of 2015. Universitas Padjadjaran (Unpad) is one of most significant areas in Jatinangor Sumedang where many people are doing their activity day and night. The purpose of the study was to identify what types of mosquito genera exist in Unpad campus according to the time and location. A field survey was conducted at 22 locations in Unpad campus using modified electric light trap placed indoor and outdoor at each site from September to November 2016. The modified electrical trap was turned on for 24 hours, and samples collected every 12 hours. Mosquitoes trapped were put into the plastic cup, labeled according to time collected, and brought to Parasitology Laboratory of Unpad for identification. The study result identified four types of mosquito genera which were Culex spp. (405), Armigeres spp. (70), Aedes spp. (33), and Anopheles spp. (10). Prevention toward potential breeding sites and protection using window net should be considered to reduce the risk of vector-borne diseases. In conclusion, Aedes spp. is the most active mosquito during the day while Culex spp. and Armigeres spp. are the most active mosquito during the night. SURVEI NYAMUK DI KAWASAN KAMPUS UNIVERSITAS PADJADJARAN  JATINANGOR PADA BULAN SEPTEMBER–NOVEMBER 2016 Kabupaten Sumedang dilaporkan sebagai salah satu daerah endemik demam berdarah di Jawa Barat. Jumlah pasien demam berdarah yang datang ke Rumah Sakit Umum Daerah Sumedang meningkat dalam tiga bulan terakhir pada tahun 2015. Universitas Padjadjaran (Unpad) merupakan salah satu wilayah yang terluas di Jatinangor Sumedang sebagai tempat banyak orang melakukan aktivitas pada siang dan malam hari. Tujuan penelitian ini adalah mengidentifikasi jenis genera nyamuk yang ada di kampus Unpad Jatinangor berdasar atas waktu dan lokasi. Survei lapangan dilakukan pada 22 lokasi di kampus Unpad Jatinangor pada bulan September–November 2016 menggunakan perangkap nyamuk cahaya yang dimodifikasi. Perangkap nyamuk ditempatkan di dalam dan luar ruangan untuk setiap lokasi. Perangkap nyamuk dipasang selama 24 jam, kemudian nyamuk dikumpulkan setiap 12 jam. Nyamuk yang terperangkap dikumpulkan dan dimasukkan ke dalam cangkir plastik, diberi label sesuai dengan waktu pengambilan, kemudian dibawa ke Laboratorium Parasitologi Unpad untuk diidentifikasi. Hasil penelitian menunjukkan 4 genera nyamuk ditemukan di kampus Unpad Jatinangor, yaitu Culex spp. (405), Armigeres spp. (70), Aedes spp. (33), dan Anopheles spp. (10). Pencegahan pada tempat yang berpotensi menjadi sarang nyamuk dan perlindungan menggunakan kawat nyamuk pada jendela harus dipertimbangkan untuk menurunkan risiko penyakit tular vektor. Simpulan penelitian ini, Aedes spp. merupakan nyamuk yang paling aktif pada siang hari serta Culex spp. dan Armigeres spp. yang paling aktif pada malam hari.

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Mosquito Survey in the Campus Area of Universitas Padjadjaran Jatinangor in September to November 2016

Nigeria has a high burden of vector borne diseases such as malaria and lymphatic filariasis (LF). This study aimed to determine the species composition of mosquitoes in Ibadan, Southwest Nigeria as well as determine their role in malaria and LF transmission. Adult mosquitoes were collected by Pyrethrum Spray Catch (PSC) and identified and graded according to their abdominal conditions. The mosquitoes were dissected to determine the parity status and to check for microfilariae of Wuchereria bancrofti. The presence of circumsporozoite protein of Plasmodium falciparum was examined using ELISA. A total of 1600 mosquitoes were collected of which 31 (1.9%) were Anopheles gambiae s.l. while 1756 (98%) were Culex sp. None of the mosquitoes examined was positive for Plasmodium falciparum and Wuchereria bancrofti. The lack of adequate sanitary conditions in the area could be responsible for the large number of mosquitoes collected. Health education could help in sensitizing the inhabitants.

https://www.entomoljournal.com/vol2Issue4/pdf/11.1.pdf

Olayemi M. Awobifa

Papers

Species composition and temporal distribution of mosquito populations in Ibadan, Southwestern Nigeria.