Culicine Mosquitoes Research Articles

Surveillance of Mosquitoes (Diptera, Culicidae) in Kyiv, Ukraine Between 2013 and 2017.

For effective control of vector-borne diseases and control of nuisance-biting insects, it is important to know which species are present and their relative abundance. In this study, we report data from a State-supported mosquito surveillance program in Kyiv, Ukraine's capital city. The surveillance identified 29 different species: 24 Culicines and 5 Anopheline species. Culicine mosquitoes included 17 in the genus Aedes, 3 Culex, 3 Culiseta, and 1 Mansonia species. The relative abundance of each genera was consistent in years 2014, 2015, and 2016; namely Aedes>Culex>Anopheles. In 2017, Aedes and Culex mosquitoes were approximately the same, predominating over Anopheles. A declining trend in the numbers of mosquitoes collected from 2013 to 2017 has not only several potential explanations, including increased urbanization and more effective control, but also may reflect changes in surveillance efforts.

A mosquito small RNA genomics resource reveals dynamic evolution and host responses to viruses and transposons.

Although mosquitoes are major transmission vectors for pathogenic arboviruses, viral infection has little impact on mosquito health. This immunity is caused in part by mosquito RNA interference (RNAi) pathways that generate antiviral small interfering RNAs (siRNAs) and Piwi-interacting RNAs (piRNAs). RNAi also maintains genome integrity by potently repressing mosquito transposon activity in the germline and soma. However, viral and transposon small RNA regulatory pathways have not been systematically examined together in mosquitoes. Therefore, we developed an integrated mosquito small RNA genomics (MSRG) resource that analyzes the transposon and virus small RNA profiles in mosquito cell cultures and somatic and gonadal tissues across four medically important mosquito species. Our resource captures both somatic and gonadal small RNA expression profiles within mosquito cell cultures, and we report the evolutionary dynamics of a novel Mosquito-Conserved piRNA Cluster Locus (MCpiRCL) made up of satellite DNA repeats. In the larger culicine mosquito genomes we detected highly regular periodicity in piRNA biogenesis patterns coinciding with the expansion of Piwi pathway genes. Finally, our resource enables detection of cross talk between piRNA and siRNA populations in mosquito cells during a response to virus infection. The MSRG resource will aid efforts to dissect and combat the capacity of mosquitoes to tolerate and spread arboviruses.

Targeting female flight for genetic control of mosquitoes.

Aedes aegypti Act4 is a paralog of the Drosophila melanogaster indirect flight muscle actin gene Act88F. Act88F has been shown to be haploinsufficient for flight in both males and females (amorphic mutants are dominant). Whereas Act88F is expressed in indirect flight muscles of both males and females, expression of Act4 is substantially female-specific. We therefore used CRISPR/Cas9 and homology directed repair to examine the phenotype of Act4 mutants in two Culicine mosquitoes, Aedes aegypti and Culex quinquefasciatus. A screen for dominant female-flightless mutants in Cx. quinquefasciatus identified one such mutant associated with a six base pair deletion in the CxAct4 coding region. A similar screen in Ae. aegypti identified no dominant mutants. Disruption of the AeAct4 gene by homology-dependent insertion of a fluorescent protein marker cassette gave a recessive female-flightless phenotype in Ae. aegypti. Reproducing the six-base deletion from Cx. quinquefasciatus in Ae. aegypti using oligo-directed mutagenesis generated dominant female-flightless mutants and identified additional dominant female-flightless mutants with other in-frame insertions or deletions. Our data indicate that loss of function mutations in the AeAct4 gene are recessive but that short in-frame deletions produce dominant-negative versions of the AeAct4 protein that interfere with flight muscle function. This makes Act4 an interesting candidate for genetic control methods, particularly population-suppression gene drives targeting female viability/fertility.

Monitoring Culicine Mosquitoes (Diptera: Culicidae) as a Vector of Flavivirus in Incheon Metropolitan City and Hwaseong-Si, Gyeonggi-Do, Korea, during 2019.

The flaviviruses are small single-stranded RNA viruses that are typically transmitted by mosquitoes or tick vectors and are etiological agents of acute zoonotic infections. The viruses are found around the world and account for significant cases of human diseases. We investigated population of culicine mosquitoes in central region of Korean Peninsula, Incheon Metropolitan City and Hwaseong-si. Aedes vexans nipponii was the most frequently collected mosquitoes (56.5%), followed by Ochlerotatus dorsalis (23.6%), Anopheles spp. (10.9%), and Culex pipiens complex (5.9%). In rural regions of Hwaseong, Aedes vexans nipponii was the highest population (62.9%), followed by Ochlerotatus dorsalis (23.9%) and Anopheles spp. (12.0%). In another rural region of Incheon (habitat of migratory birds), Culex pipiens complex was the highest population (31.4%), followed by Ochlerotatus dorsalis (30.5%), and Aedes vexans vexans (27.5%). Culex pipiens complex was the predominant species in the urban region (84.7%). Culicine mosquitoes were identified at the species level, pooled up to 30 mosquitoes each, and tested for flaviviral RNA using the SYBR Green-based RT-PCR and confirmed by cDNA sequencing. Three of the assayed 2,683 pools (989 pools without Anopheles spp.) were positive for Culex flaviviruses, an insect-specific virus, from Culex pipiens pallens collected at the habitats for migratory birds in Incheon. The maximum likelihood estimation (the estimated number) for Culex pipiens pallens positive for Culex flavivirus was 25. Although viruses responsible for mosquito-borne diseases were not identified, we encourage intensified monitoring and long-term surveillance of both vector and viruses in the interest of global public health.

Species composition, blood meal sources and insecticide susceptibility status of Culex mosquitoes from Jimma area, Ethiopia

Different species of Culex mosquitoes are present in high numbers in many other countries in addition to sub-Saharan Africa and Asian countries. Culex mosquitoes are serious nuisance which also transmit a range of pathogens including several viruses such as West Nile virus, Saint Louis encephalitis, and Rift Valley fever, as well as parasites such as avian malaria, and filarial worms. In Ethiopia, unlike Anopheles mosquitoes, little effort was given to study habitat, species composition, blood meal sources and insecticide susceptibility status of Culex mosquitoes. Therefore, this study aimed to assess the species composition, their blood meal source and insecticide susceptibility status of Culex mosquitoes to some of selected insecticides in Jimma town southwest Ethiopia. Culicine mosquito larvae were collected using a standard dipper (by dipping) from a range of breeding sites and reared to adults. Species identification was carried out using standard keys. Bioassay tests were performed on adults to assess the susceptibility of Culex mosquitoes to insecticide-impregnated papers with Dichlorodiphenyltrichloroethane (DDT (4%), mlathion (5%), bendiocarb (0.1%), propoxur (0.1%), deltamethrin (0.05%) and pirimiphos-methyl (0.25) following World Health Organization Pesticide Evaluation Scheme (WHOPES) guideline. Moreover, 184 blood fed (BF) Culex mosquitoes were collected using aspirator from indoor and outdoor resting and assayed to assess blood meal sources using Enzyme-Linked Immunosorbent Assay (ELISA). The result of the study showed that among the collected Culex moquitoes, two species were identified as Culex quinquefasciatus and Cx antennatus whereas the remaining one could not be identified to species level. Culex mosquitoes were found to be resistant to DDT, malathion, bendiocarb, propoxur, and deltamethrin whereas susceptible to pirimiphos-methyl. The blood meal source analysis using Enzyme-Linked Immunosorbent Assay (ELISA) showed higher blood source of human (33.2%) than bovine (15.2%). Thus, the observed resistance to the most of the insecticides coupled with higher human blood meal source calls further studies to be carried out in Culex mosquito populations of Ethiopia.

Surveillance of Culicine Mosquitoes in Six Villages of Taita-Taveta County, Kenya, With Host Determinations From Blood-Fed Females.

Culicine mosquitoes are vectors of human disease-causing pathogens like filarial worms and several arthropod-borne viruses (arboviruses). Currently, there has been an increase in emerging and re-emerging vector-borne diseases along coastal Kenya, which has been of major concern in public health. This study aimed at determining culicine mosquito species abundance, diversity and their host feeding preferences in Taita-Taveta County, Coastal Kenya. Entomological sampling was done during the long-wet season (March and May) and long dry season (June to October) 2016-2018. Mosquito sampling was done using CDC light traps and Backpack aspiration for indoor and outdoor environments. All culicine mosquitoes collected were identified morphologically and categorized according to their physiological status. Blood fed culicine mosquitoes were tested for bloodmeal sources using ELISA. In total, 3,278 culicine mosquitoes were collected, of which 738 (22.5 %) were found indoors and 2,540, (77.5 %) outdoors. The mosquitoes consisted of 18 species belonging to four genera: Aedes (7), Culex (8), Mansonia (2), and Coquillettidia (1). Overall, there was high mosquito species diversity (H) in outdoors (H = 2.4339) than in indoors (H = 2.2523), whereas even distribution (EH) was higher in indoors (EH = 0.9064) than outdoors (EH = 0.8266). Majorly the bloodmeals identified were from multiple host sources with (51.6%), single hosts (41.3%), and unidentified (7.2%). This study has demonstrated a high diversity of culicine mosquitoes with relaxed feeding tendencies. These mosquitoes are contributing to mosquito biting nuisance and the likelihood of exposure of populations to diseases of public health.

Expanding the CRISPR Toolbox in Culicine Mosquitoes: In Vitro Validation of Pol III Promoters.

CRISPR–Cas9-based “gene drive” technologies have been proposed as a novel and effective means of controlling human diseases vectored by mosquitoes. However, more complex designs than those demonstrated to date—and an expanded molecular toolbox with which to build them—will be required to overcome the issues of resistance formation/evolution and drive spatial/temporal limitation. Foreseeing this need, we assessed the sgRNA transcriptional activities of 33 phylogenetically diverse insect Polymerase III promoters using three disease-relevant Culicine mosquito cell lines (Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus). We show that U6 promoters work across species with a range of transcriptional activity levels and find 7SK promoters to be especially promising because of their broad phylogenetic activity. We further show that U6 promoters can be substantially truncated without affecting transcriptional levels. These results will be of great utility to researchers involved in developing the next generation of gene drives.

Retrospective review and current knowledge on the occurrence of West Nile virus in mosquito vectors, reservoirs and hosts in Slovakia (Central Europe).

West Nile virus (WNV) is amosquito-borne flavivirus (the genus Flavivirus) representing amedical and veterinary public health concern. Birds are the most important reservoirs. Culicine mosquitoes transmit WNV to vertebrate hosts (including horses and humans) and migratory birds play role in its long-distance transport. Slovakia is geographically localised at the crossroad of migration routes connecting South Europe and Africa with breeding localities in the Western, Northern, Central and Eastern Europe and Siberia. This review summarizes historical and present knowledge on WNV in Slovakia during a period of more than fifty years. Five European mosquito species capable to transmit WNV are native in Slovakia. Based on recent research results, the major role in the WNV transmission is attributed to Culex mosquitoes, which are also the most abundant species. Virus isolates from birds that succumbed to WNV infection are genetically close to Central European strains. Historical and recent results point out, that WNV circulates in the population of vectors, reservoirs and hosts for decades. Although West Nile fever epidemics in Slovakia were not reported yet, virus isolation, molecular detection and serological findings in reservoirs and hosts confirm that sporadic cases occur. Furthermore, the first autochthonous human case may indicate favourable conditions for WNV transmission to humans. The climate change and precipitation anomalies may favour to increase vector abundance, hence increase the chance of WNV epidemics. This review highlights an urgent need of a countrywide surveillance program aimed on the WNV occurrence in vectors and reservoirs in Slovakia. Keywords: West Nile virus; flavivirus; vector-borne pathogen; arbovirus.

Three-year surveillance of culicine mosquitoes (Diptera: Culicidae) for flavivirus infections in Incheon Metropolitan City and Hwaseong-si of Gyeonggi-do Province, Republic of Korea

Japanese encephalitis virus (JEV) is a single stranded positive sense RNA virus of the genus Flavivirus that belongs to family Flaviviridae and emerged as one of the most pivotal form of viral encephalitis. The virus is transmitted to humans by mosquito vector and is an etiological agent of acute zoonotic infection. In this study, we investigated distribution and density over 3-year period in central regions of Korean peninsula. We selected two cities as mosquito-collecting locations and subdivided them into five collection sites; downtown Incheon Metropolitan City as a typical urban area, and the Hwaseong-si area as a rural area. A total of 35,445 female culicine mosquitoes were collected using black light traps or BG Sentinel™ traps from March to November 2016–2018. Aedes (Ae.) vexans nipponii was the most frequently collected specimens (48.91%), followed by Culex (Cx.) pipiens (32.05%), Ochlerotatus (Och.) dorsalis (13.58%), Och. koreicus (1.68%), and Cx. tritaeniorhynchus (1.49%). In the urban area, Cx. pipiens was the predominant species (92.21%) and the other species accounted for <5% of the total mosquitoes collected. However, in the rural area, Ae. vexans nipponii had the highest population (61.90%), followed by Och. dorsalis (17.10%), Cx. tritaeniorhynchus (1.84%) and Och, koreicus (1.78%). Culicine mosquitoes were identified at the species level, placed in pools of up to 30 mosquitoes each, and screened for flavivirus RNA using the SYBR Green-based RT-PCR. Three of the assayed 1092 pools were positive for Chaoyang virus from Ae. vexans nipponii and Japanese encephalitis virus from Cx. pipiens. The maximum likelihood estimations (the estimated number of virus-positive mosquitoes/1000 mosquitoes) for Ae. vexans nipponii positive for Chaoyang virus and Cx. pipiens for Japanese encephalitis virus were 3.095 and 0.20, respectively. The results of our study demonstrate that although mosquito-borne diseases were not detected in the potential vectors, enhanced monitoring and long-term surveillance of these vector viruses are of great public health importance.

Embryo polarity in moth flies and mosquitoes relies on distinct old genes with localized transcript isoforms.

Unrelated genes establish head-to-tail polarity in embryos of different fly species, raising the question of how they evolve this function. We show that in moth flies (Clogmia, Lutzomyia), a maternal transcript isoform of odd-paired (Zic) is localized in the anterior egg and adopted the role of anterior determinant without essential protein change. Additionally, Clogmia lost maternal germ plasm, which contributes to embryo polarity in fruit flies (Drosophila). In culicine (Culex, Aedes) and anopheline mosquitoes (Anopheles), embryo polarity rests on a previously unnamed zinc finger gene (cucoid), or pangolin (dTcf), respectively. These genes also localize an alternative transcript isoform at the anterior egg pole. Basal-branching crane flies (Nephrotoma) also enrich maternal pangolin transcript at the anterior egg pole, suggesting that pangolin functioned as ancestral axis determinant in flies. In conclusion, flies evolved an unexpected diversity of anterior determinants, and alternative transcript isoforms with distinct expression can adopt fundamentally distinct developmental roles.

Activities of Some Ethnobotanicals from North East Nigeria, against Culicine Mosquitoes

Mosquito borne diseases are the major cause of economic loss due to high morbidity and mortality in Africa. Elimination of culicine vectors using ethnobotanical extracts is one of the best methods for controlling mosquito-borne diseases. The methanolic and petroleum ether extracts of five plants, Azadirachta indica (neem), Hyptis suaveolens (bush tea), Eucarlyptus globulus (pole wire), Citrus senensis (orange), and Ocimumkilimanscharicum (bush scent leaf), were investigated for their effectiveness in control of subfamilies Culicidae mosquitoes’ larvae from June 2017 to October 2017. The results showed that the mortality is concentration dependent. Mortality was recorded for both methanol and petroleum ether extracts. Higher mortalities were observed in the methanolic extracts than petroleum ether extracts. The different plant extracts showed high significant differences (p&lt; 0.05) to each other. Hyptis suaveolens proved to be the most effective treatment agent with 100% mortality observed at both 150 ppm and 200 ppm. The present study has demonstrated larvicidal effects, and the effects were extended pupae emerged from the different treatment which led to the low adult emergence as compared to the control.

Phytochemical Screening and Larvicidal Activities of Some Ethnobotanicals from North Eastern Nigeria against Culicine (Dipera: Culicidae) Mosquito

This study was aimed to investigate the insecticidal activities of some selected ethnobotanicals against culicine mosquitoes. Various part of plant material collected were extracted using Soxhlet apparatus Methanol and Petroleum ether were used as solvents. Quantitative phytochemical Analysis for the crude extracts was carried out for the presence of azadrachtin, terpenoids, alkaloids, tannins, saponins, glycoside, steroids phenol and flavonoids. The larvicidal potentials of the various crude extracts were then tested against culicine mosquitoes.&#x0D; More yields of phytochemical constituents (80.78 mg) were found in total of 900 g used for methanol extracts as compared to 57.64 mg found in 900 g used in petroleum ether extracts. All the extracts of methanol and petroleum ether of the different plant used showed larvicidal potentials against culicine 3rd instar larvae. The LC50 of the methanol extracts (37.32, 38.52, 42.05, 45.91, 68.78, 126.56, and 141.73 ppm) of E. globulus, O. kilimanscharicum, H. suaveolens, Neem seeds, neem stem leave and orange peels respectively, are far better than their counterparts of petroleum ether extracts with LC50 (100.25, 115.53, 145.88, 68.44, 114.55, 46.79, and 175.07 ppm). The larvicidal effect of individual isolates of alkaloids, tannin, saponins, azadirachtin, phenol and steroids demonstrated larvicidal potentials against 3rd instar larvae of culicine, where, terpenoids, flavonoids and glycoside showed no larvicidal potentials against culicine larvae. The larvicidal potential of each plant depend on the number of active ingredients and quantity available in each extract.&#x0D; In conclusion, the present plant extracts have potentials for development of new and safe control products for culicine mosquitoes.

Videographic analysis of flight behaviours of host-seeking Anopheles arabiensis towards BG-Malaria trap.

The BG-Malaria trap (BGM) is an adaptation of the well-known BG-Sentinel trap (BGS) with greater trapping efficiencies for anopheline and culicine mosquitoes. Its continued optimization requires greater understanding of mosquito flight behaviors near it. We used three high-resolution infrared cameras (68 frames/second) to track flight behaviors of laboratory-reared Anopheles arabiensis females in vicinity of the BGM in comparison with BGS. Additional comparisons were done for BGM at 20, 40 and 80cm heights, and for BGMs baited with Ifakara blend plus CO2, CO2 alone, or no bait. More mosquitoes were observed near BGM than BGS. Both BGMs installed 20cm above the floor and baited with CO2 received more visits by host-seeking mosquitoes than the other BGMs evaluated in their respective experiments. Trap designs, height and attractants all influence mosquito activity in vicinity of the traps which can be readily visualized using infrared cameras to accelerate trap development and testing. The greater activity of host-seeking mosquitoes near BGM than BGS supports the proven superiority of BGM traps in field and semi-field settings.

Predation differentially structures immature mosquito populations in stormwater ponds

1. Understanding the factors underlying the abundance and distribution of species requires the consideration of a complex suite of interacting biotic and abiotic factors operating on multiple spatial and temporal scales. Larval mosquitoes inhabiting small human‐constructed ponds represent a unique opportunity to investigate the relative importance of these structuring mechanisms while simultaneously generating applied knowledge on mosquito control.2. A multi‐year field survey of 32 stormwater ponds was conducted in central Illinois (Champaign County). From each pond, data were collected on pond structure type and hydroperiod, the presence/absence of cattails (Typha spp.), and measures of total nitrogen, phosphorus, and organic carbon, and chlorophyll a. The communities of crustacean zooplankton and aquatic insects were characterised, and these taxa were assigned into two main groups: predators and competitors of larval mosquitoes. Structural equation modelling was used to explore the direct and indirect effects of these biotic and abiotic factors on larval density for three species of culicine mosquitoes (Culex pipiens, Culex restuans, and Aedes vexans).3. Hydroperiod had an indirect negative effect on C. pipiens density. However, this effect was mediated by predator density; more permanent ponds had more predators, which therefore reduced the density of C. pipiens larvae. Aedes vexans density was positively correlated with predator density. No predictor variables were found that explained variation in C. restuans density.4. This study show that the relative importance of these biotic and abiotic factors varies among species of culicine mosquitoes inhabiting stormwater ponds.

Bio-efficacy and physical integrity of piperonylbutoxide coated combination net (PermaNet\xae 3.0) against pyrethroid resistant population of Anopheles gambiae s.l. and Culex quinquefasciatus mosquitoes in Ethiopia

BackgroundPermaNet® 3.0 is a deltamethrin-treated combination long-lasting insecticidal net with the addition of synergist piperonylbutoxide (PBO) on its roof section. It is designed to overcome the challenge posed by pyrethroid resistant vector populations against mainstream long-lasting insecticidal nets impregnated with pyrethroids only. The objective of this study was to determine insecticide resistance status of Anopheline and Culicine mosquitoes, to evaluate the bio-efficacy of PermaNet® 3.0 nets and to assess household factors affecting the physical integrity of PermaNet® 3.0 after 3 years of use.MethodsInsecticide susceptibility test was conducted using the WHO tube test. Bio-activity of PermaNet® 3.0 samples was evaluated using the WHO cone bioassay. Cross-sectional survey was conducted on 150 randomly selected households from two districts to determine household factors affecting net utilization. One hundred fifty PermaNet® 3.0 nets were randomly collected from the community with replacement after 3 years of deployment and physical integrity of each net was assessed.ResultsBoth Anopheles gambiae sensu lato and Culex quinquefasciatus developed resistance against permethrin and deltamethrin. However, following pre-exposure to synergist PBO the susceptibility of mosquito population increased to both permethrin (from 39% without to 92% with PBO against An. gambiae and from 28% without to 94% with PBO against Culex quinquefasciatus) and deltamethrin (from 52% without to 99% with PBO against An. gambiae and from 43% without to 98% with PBO against Culex quinquefasciatus). Eighty percent (80%) mortality was recorded in wild population of An. gambiae s.l. exposed to unused PermaNet® 3.0, but its bioactivity subsequently declined as washing frequency increased from 0 to 20. The PBO coated roof section of unused PermaNet® 3.0 resulted in higher mosquito mortality (100%) compared to the side panels without PBO (85%). House structure, cooking and washing habits, and damage due to household pests were cited as determinants associated with bed net deterioration. Bed net proportionate hole index (pHI) was ranged from 0 to 6064. Of the 150 PermaNet® 3.0 nets assessed 80, 29 and 41 were considered as ‘good’, ‘acceptable’ and ‘too torn’, respectively.ConclusionsThe bio-efficacy evaluation of PermaNet® 3.0 from Jimma area, southwestern Ethiopia showed moderate efficacy against pyrethroid resistant population of An. gambiae and Culex quinquefasciatus. Thus, NMCPs in parallel to deployment of LLINs, should implement timely insecticide resistance management and integrated vector management strategies to slowdown the evolution and further spread of insecticide resistance. Household factors such as, housing conditions, open flame fire used for cooking and rodent attack were identified as factors contributing to the observed reduced bed net physical integrity in the study area. Universal coverage of bed nets should be accompanied with community awareness creation and training on net utilization and handling.

Mosquito dynamics and malaria in Alulu-Nike Commnuity, Enugu East Local Government Area, Enugu State, Nigeria

Malaria is endemic and stable, being a major cause of morbidity and mortality in Nigeria. Malaria prevalence and mosquito dynamics were studied in the rural villages of Alulu-Nike Community, Enugu East Local Government Area of Enugu State for a period of 12 months. Malaria was diagnosed with microscopy method. Mosquito collection was done using pyrethroid knockdown collection method for indoor biting and resting adult mosquitoes; human bait method for outdoor adult mosquito and larval collection from different breeding sites. Mosquito identification was done using morphological characteristics and PCR. A total of 1,440 people were screened for malaria and 476(32.4%) were infected. The overall mean malaria intensity was 545 parasites per microlitre of blood (p/μl). Nnegbune Village had the highest malaria prevalence 86 (41.5%) which was significant (p&lt;0.05) and the highest mean malaria intensity 741 p/μl. Age 0-10 years had the highest malaria prevalence 229(44.7) and mean intensity 991 p/μl. The age specific malaria prevalence was statistically significant (p&lt;0.05). Malaria intensity was not significant in all categories. Malaria prevalence and intensity were not dependent on sex and occupation of the participants (p&gt;0.05). The primary education group 204(38.6) and the nonformal education group 63(34.2) were mostly infected while the tertiary education group were the least infected 68(26.6) which was significant (p&lt;0.05). PCR characterization of the 990 indoor biting and resting adult mosquitoes revealed Anopheles gambiae ss and A. arabiensis as the sibling species of A. gambiae sl. A. gambiae ss, A. arabiensis and A. funestus (malaria vectors) constituted 764 (77.1%) while the Culicines accounted for 226(22.8%) of the total indoor collection. The highest malaria vectors as well as the highest mosquitoes were collected from Nnegbune village. Of the 694 outdoor biting adult mosquitoes collected. A. gambiae sl 7(1.0%) was the only malaria vector collected while other species of culicine mosquitoes accounted for 687(98.99%) of the outdoor collections. A total of 1,162 mosquito larvae were collected from different villages of Alulu-Nike Community out of which A. gambiae yielded 45(3.9%) while culicine mosquitoes yielded 1,117(96.1%) of the total larval sampling. The highest collection of larvae was from used and discarded tyres 822 (70.7%). Mosquitoes were more abundant in wet months than in dry months. The distribution of indoor and outdoor mosquitoes and larvae in different villages and in different months showed significant results (p&lt;0.05). Entomological study of mosquitoes is important for planning and optimizing malaria control in both time and space.Keywords: Malaria; Anopheles mosquitoes; culicines

DNA-aided identification of Culex mosquitoes (Diptera: Culicidae) reveals unexpected diversity in underground cavities in Austria

Subterranean cavities serve as resting places and hibernation shelters for mosquitoes. In Europe, members of the genus Culex are often the most abundant insects on cave walls. Culex pipiens L., the common house mosquito, exists in two physically very similar, yet genetically and ecologically distinct biotypes (or forms, ‘f.’), namely Cx. pipiens f. pipiens and Cx. pipiens f. molestus. Autogeny and stenogamy of the latter form have been interpreted as adaptations to underground habitats. The epigean occurrence of the two biotypes and their hybrids was recently examined in Eastern Austria, but the hypogean distribution of the Cx. pipiens complex and morphologically similar non-members such as Cx. torrentium is unknown. Considering the key role of Culex mosquitoes in the epidemiology of certain zoonotic pathogens, the general paucity of data on species composition and relative abundance in subterranean shelters appears unfortunate.For a first pertinent investigation in Austria, we collected mosquitoes in four eastern federal states. Based on analyses of the ACE2 gene and the CQ11 microsatellite locus, 150 female and three male mosquitoes of the genus Culex, two females of the genus Culiseta and a single female of the genus Anopheles were determined to species level or below. In our catches, Cx. pipiens f. pipiens exceeded the apparent abundance of the purportedly cave-adapted Cx. pipiens f. molestus many times over. Records of Cx. hortensis and Cx. territans, two species rarely collected in Austria, lead us to infer that underground habitats host a higher diversity of culicine mosquitoes than previously thought.

Ecology of Preimaginal Culicine Mosquitoes in Rock Pools on Inselbergs Within Kaduna State, Nigeria

Ecological investigations were conducted between June and October 2013 on the species composition of culicine mosquitoes breeding in discrete rock pool habitats and chemistry of their microhabitats on inselbergs within Kaduna State, Nigeria. Standard soup ladle dipper (0.105L capacity) was used to obtain representative samples of preimaginal stages of mosquito into plastic bowls. HANNA HI98129 pH/EC/TDS/TEMP meter was used to determine habitats' physicochemical parameters in situ. Habitats' turbidity, alkalinity, total suspended solids, total hardness, Chemical oxygen demand, phosphate and nitrate levels were determined following standard laboratory protocols. Fully developed (4th instar) larvae were preserved with 70% ethanol in labelled specimen bottles while larvae in their lower instars were nurtured on baker's yeast diet in the laboratory, prior to preservation. Mosquitoes were identified microscopically to species by means of pictorial morphological keys. Data were analysed by ANOVA, Pearson correlation and principal component analyses. A total of 269 (69.69%) of the 386 rock pools examined were positive with culicine mosquitoes, yielding 31691 larvae belonging to seven species. These included 30366 (95.97%) Aedes vittatus, 266 (0.84%) Culex albiventris, 105 (0.33%) Culex horridus, 241 (0.76%) Culex macfiei, 139 (0.44%) Culex pipiens pipiens, 523 (1.65%) Culex perfidiosus, 1 (0.003%) Culex simpsoni and 1 (0.003%) Culex tigripes. The mosquitoes bred as sole, double, triple and quadruple conspecific, heterospecific, congeneric and heterogeneric combinations. Specific ranges of breeding habitats' parameters were depths (0.4-65cm), surface areas (1.5-1970m 2 ), temperatures (22.8-36.5°C), pH(7.05-12.69), TDS (0-276ppm), EC (0-572µscm -1 ), TSS (10-150mgL -1 ), turbidity (1.97-178NTU), hardness (30.3-545.4 mgL -1 ), COD (80-480mgL -1 ), PO 4 3- (mgL -1 ), NO 3 - (8.5- 109.4 mgL -1 ) and alkalinity (2-111mgL -1 ). Water temperature and hardness were determinants of spatial distribution of mosquitoes in the rock pools. TDS, EC and akalinity significantly correlate with mosquito larval abundance in rock pools (P<0.001). The study observed widespread breeding of noxious mosquito vectors of diseases in rock pools throughout the State and recommends their targeted control in situ.

Diverse novel resident Wolbachia strains in Culicine mosquitoes from Madagascar

Wolbachia endosymbiotic bacteria are widespread throughout insect species and Wolbachia transinfected in Aedes mosquito species has formed the basis for biocontrol programs as Wolbachia strains inhibit arboviral replication and can spread through populations. Resident strains in wild Culicine mosquito populations (the vectors of most arboviruses) requires further investigation given resident strains can also affect arboviral transmission. As Madagascar has a large diversity of both Culicine species and has had recent arboviral outbreaks, an entomology survey was undertaken, in five ecologically diverse sites, to determine the Wolbachia prevalence. We detected diverse novel resident Wolbachia strains within the Aedeomyia, Culex, Ficalbia, Mansonia and Uranotaenia genera. Wolbachia prevalence rates and strain characterisation through Sanger sequencing with multilocus sequence typing (MLST) and phylogenetic analysis revealed significant diversity and we detected co-infections with the environmentally acquired bacteria Asaia. Mosquitoes were screened for major arboviruses to investigate if any evidence could be provided for their potential role in transmission and we report the presence of Rift Valley fever virus in three Culex species: Culex tritaeniorhynchus, Culex antennatus and Culex decens. The implications of the presence of resident Wolbachia strains are discussed and how the discovery of novel strains can be utilized for applications in the development of biocontrol strategies.

Japanese Encephalitis: a life threatening disease

Japanese encephalitis (JE) is neurological infection which is caused by Japanese encephalitis virus (JEV), a flavivirus, and is closely related to St. Louis encephalitis and West Nile encephalitis. It is predominant in rural areas of Asia, which spread through bites of culicine mosquitoes, most often Culex tritaeniorhynchus. JE has broad range of manifestations. It can range from subtle changes in behavior to serious problems, including blindness, ataxia, weakness, and movement disorders.Japanese encephalitis virus is endemic in 24 countries in Southeast Asia and Western Pacific regions with more than 3 billion people at risk of infection. JE is the main cause of viral encephalitis in people in many countries of Asia amounting almost 68,000 clinical cases per year. Children are at greatest risk, with adults in endemic areas having protective immunity as a consequence of childhood infection. This disease is of particular importance in Gorakhpur, eastern belt of UP, the state with the largest population in India, where a large number of children have been dying in the past several years with alarming frequency since 1978.