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The mosquitoes (Diptera: Culidae) of Seychelles: taxonomy, ecology, vectorial importance, and identification keys  [cached]
Le Goff Gilbert,Boussès Philippe,Julienne Simon,Brengues Cécile
Parasites & Vectors , 2012, DOI: 10.1186/1756-3305-5-207
Abstract: Background During recent periods, the islands of the Republic of Seychelles experienced many diseases such as dengue, chikungunya, Bancroft’s filaria and malaria. Mosquitoes transmit the agents that cause these diseases. Published information on mosquitoes in the Seychelles is notably dispersed in the literature. The maximum number of species obtained on a single field survey does not exceed 14 species. Methods We performed a comprehensive bibliographic review using mosquito and Seychelles as the key words, as well as conducted a mosquito field survey for larval and adult stages during the rainy season in December 2008. Sixteen sites were sampled on four granitic islands (Mahé, Praslin, La Digue and Aride) and six sites on coralline atolls in the extreme southwest of the country (Aldabra group). Results We found published references to 21 mosquito species identified at least on one occasion in the Seychelles. Our collections comprised 18 species of mosquitoes, all of them from the subfamily Culicinae; no Anophelinae was found. We also confirm that Aedes seychellensis is a junior synonym of Ae. (Aedimorphus) albocephalus. The first records for Culex antennatus and Cx. sunyaniensis are presented from the country, specifically from Aldabra and Praslin, respectively. Based on a comparison of the taxa occurring on the granitic versus coralline islands, only three species, Ae. albocephalus, Cx. scottii and Cx. simpsoni are shared. Aedes albopictus appeared to exclude largely Ae. aegypti on the granitic islands; however, Ae. aegypti was common on Aldabra, where Ae. albopictus has not been recorded. The notable aggressiveness of mosquitoes towards humans on coralline islands was mainly due to two species, the females of which are difficult to distinguish: Ae. fryeri and Ae. (Aedimorphus) sp. A. The number of mosquito species collected at least once in the Seychelles is now 22, among which five species (Ae. (Adm) sp. A, Cx. stellatus, Uranotaenia browni. Ur. nepenthes and Ur. pandani) and one subspecies (Ae. vigilax vansomerenae) are considered as endemic. Two illustrated identification keys, one for adult females and the other for larval stages, are presented. Conclusions The knowledge of the culicidian fauna in the Seychelles has been notably updated. The number of mosquito species is relatively large with regards to land surface and distances to continental Africa, although the anophelines are totally lacking. The complex natural history of mosquitoes in the Seychelles provides examples of both vicariance- and dispersal-mediated divergences. They pre
Reappraisal on anopheline mosquitoes of Garhwal region, Uttarakhand, India  [PDF]
N. Pemola Devi,R.K. Jauhari
Journal of Vector Borne Diseases , 2008,
Abstract: Background & objectives: The study examines occurrence of anopheline mosquitoes in seven districts— Dehradun, Pauri, New Tehri, Hardwar, Rudraprayag, Chamoli and Uttarkashi of Garhwal region in Uttarakhand state, India. Methods: The methodological approach comprised sampling and processing of adult/immature mosquitoes, data compilation, meteorological information and parasitological survey.Results: A total of 87 localities covering 24 tehsils/blocks were surveyed during January 2000 to December 2005 for mosquito sampling. The study encountered 18 species of anophelines including three malaria vectors namely Anopheles culicifacies, An. fluviatilis and An. stephensi collected from Kalsi, Dehradun City, Sahaspur, Hardwar town, Roorkee, New Tehri town and Kotdwar localities. An. pallidus has been recorded for the first time from the Garhwal region. All the collected species have been presented with particular reference to their both adult and immature distribution, brief account of bionomics and some ecological notes.Interpretation & conclusion: Out of 18 collected anopheline species, 15 were non-vectors and they were found to create nuisance to the inhabitants. As far as the species distribution was concerned the diversity was more at elevation between 150 and 1000 m above the mean sea level, while the immature of some species were not recovered from those localities where their adults were collected. Certain species of Anopheles were climate determined and their distribution was localized while some others were cosmopolitan.
A review of mixed malaria species infections in anopheline mosquitoes
Mallika Imwong, Supatchara Nakeesathit, Nicholas PJ Day, Nicholas J White
Malaria Journal , 2011, DOI: 10.1186/1475-2875-10-253
Abstract: The biomedical literature was searched for studies of malaria infection and species identification in trapped wild mosquitoes and artificially infected mosquitoes. The study location and year, collection methods, mosquito species, number of specimens, parasite stage examined (oocysts or sporozoites), and the methods of parasite detection and speciation were tabulated. The entomological results in South East Asia were compared with mixed infection rates documented in patients in clinical studies.In total 63 studies were identified. Individual anopheline mosquitoes were examined for different malaria species in 28 of these. There were 14 studies from Africa; four with species evaluations in individual captured mosquitoes (SEICM). One study, from Ghana, identified a single mixed infection. No mixed infections were identified in Central and South America (seven studies, two SEICM). 42 studies were conducted in Asia and Oceania (11 from Thailand; 27 SEICM). The proportion of anophelines infected with Plasmodium falciparum parasites only was 0.51% (95% CI: 0.44 to 0.57%), for P. vivax only was 0.26% (95% CI: 0.21 to 0.30%), and for mixed P. falciparum and P. vivax infections was 0.036% (95% CI: 0.016 to 0.056%). The proportion of mixed infections in mosquitoes was significantly higher than expected by chance (P < 0.001), but was one fifth of that sufficient to explain the high rates of clinical mixed infections by simultaneous inoculation.There are relatively few data on mixed infection rates in mosquitoes from Africa. Mixed species malaria infections may be acquired by simultaneous inoculation of sporozoites from multiply infected anopheline mosquitoes but this is relatively unusual. In South East Asia, where P. vivax infection follows P. falciparum malaria in one third of cases, the available entomological information suggests that the majority of these mixed species malaria infections are acquired from separate inoculations.Where transmission of both vivax and falcipar
Interrupting malaria transmission by genetic manipulation of anopheline mosquitoes  [PDF]
Marcelo Jacobs-Lorena
Journal of Vector Borne Diseases , 2003,
Abstract: Malaria ranks among the deadliest infectious diseases that kills more than one million persons everyyear. The mosquito is an obligatory vector for malaria transmission. In the mosquito, Plasmodiumundergoes a complex series of developmental events that includes transformation into severaldistinct morphological forms and the crossing of two different epithelia—midgut and salivarygland. Circumstantial evidence suggests that crossing of the epithelia requires specific interactionsbetween Plasmodium and epithelial surface molecules. By use of a phage display library we haveidentified a small peptide-SM1—that binds to the surfaces of the mosquito midgut and salivaryglands. Transgenic Anopheles stephensi mosquitoes expressing a SM1 tetramer from a bloodinducibleand gut-specific promoter are substantially impaired in their ability to sustain parasitedevelopment and transmission. A second effector gene, phospholipase A2, also impairs parasitetransmission in transgenic mosquitoes. These findings have important implications for the developmentof new strategies for malaria control.
Identification of a fibrinogen-related protein (FBN9) gene in neotropical anopheline mosquitoes
Sabrina B Oliveira, Izabela C Ibraim, Wanderli P Tadei, Jeronimo C Ruiz, Laila A Nahum, Cristiana FA Brito, Luciano A Moreira
Malaria Journal , 2011, DOI: 10.1186/1475-2875-10-21
Abstract: This article describes the identification and characterization of the fbn9 gene partial sequences from four species of neotropical anopheline primary and secondary vectors: Anopheles darlingi, Anopheles nuneztovari, Anopheles aquasalis, and Anopheles albitarsis (namely Anopheles marajoara). Degenerate primers were designed based on comparative analysis of publicly available Aedes aegypti and An. gambiae gene sequences and used to clone putative homologs in the neotropical species. Sequence comparisons and Bayesian phylogenetic analyses were then performed to better understand the molecular diversity of this gene in evolutionary distant anopheline species, belonging to different subgenera.Comparisons of the fbn9 gene sequences of the neotropical anophelines and their homologs in the An. gambiae complex (Gambiae complex) showed high conservation at the nucleotide and amino acid levels, although some sites show significant differentiation (non-synonymous substitutions). Furthermore, phylogenetic analysis of fbn9 nucleotide sequences showed that neotropical anophelines and African mosquitoes form two well-supported clades, mirroring their separation into two different subgenera.The present work adds new insights into the conserved role of fbn9 in insect immunity in a broader range of anopheline species and reinforces the possibility of manipulating mosquito immunity to design novel pathogen control strategies.Mosquito-borne diseases, including malaria and arboviruses, such as dengue, depend on complex interactions among pathogens, insect vectors, and hosts. Studies of vector immunity are of particular importance to understanding these complex interactions and could lead to the development of novel disease control strategies [1-6]. Vectorial competence, which refers to the ability of arthropods to acquire, maintain, and transmit microbial agents [7], is directly related to insect immunity. Several immunity-related genes have been identified in Old World vectors [8-10]. H
Malaria Situation and Anopheline Mosquitoes in Qom Province, Central Iran
B Farzinnia,A Saghafipour,MR Abai
Iranian Journal of Arthropod-Borne Diseases , 2010,
Abstract: "nAbstract "nBackground: The aims of this study was to analysis the current situation of malaria and to find the distribution of anopheline mosquitoes, as probable vectors of the disease, in Qom Province, central Iran. "nMethods: This study was carried out in two parts. First stage was data collection about malaria cases using recorded documents of patients in the Province health center, during 2001–2008. The second stage was entomological survey conducted by mosquito larval collection method in 4 villages with different geographical positions in 2008. Data were analyzed using Excel software. "nResults: Of 4456 blood slides, 10.9% out were positive. Most of cases were imported from other countries (90.4%), mainly from Afghanistan (56.5%) and Pakistan (16.3%). Slide positive rate showed a maximum of 16.9% and a minimum of 2.9% in 2008 and 2007, respectively. Plasmodium vivax was causative agent of 93.75% of cases, fol-lowed by P. falciparum (6.25%). More than 15 years old age group contained the most malaria reported cases (66.7%). Two Anopheles species, An. superpictus and An. claviger were collected and identified. This is the first report of Anopheles claviger in Qom Province. "nConclusion: Malaria is in the control stage in Qom Province. The rate of local transmission is very low (only 1 case), shows Anopheles superpictus, as the main malaria vector of central part of Iran, can play its role in malaria transmission in the area. "n "nKeywords: Malaria, Iran, Epidemiology
Investigations on anopheline mosquitoes close to the nest sites of chimpanzees subject to malaria infection in Ugandan Highlands
Sabrina Krief, Florence Levrero, Jean-Michel Krief, Supinya Thanapongpichat, Mallika Imwong, Georges Snounou, John M Kasenene, Marie Cibot, Jean-Charles Gantier
Malaria Journal , 2012, DOI: 10.1186/1475-2875-11-116
Abstract: Mosquitoes were collected over two years using suction-light traps and yeast-generated CO2 traps at the nesting and the feeding sites of two chimpanzee communities in Kibale National Park. The species of the female Anopheles caught were then determined and the presence of Plasmodium was sought in these insects by PCR amplification.The mosquito catches yielded a total of 309 female Anopheles specimens, the only known vectors of malaria parasites of mammalians. These specimens belonged to 10 species, of which Anopheles implexus, Anopheles vinckei and Anopheles demeilloni dominated. Sensitive DNA amplification techniques failed to detect any Plasmodium-positive Anopheles specimens. Humidity and trap height influenced the Anopheles capture success, and there was a negative correlation between nest numbers and mosquito abundance. The anopheline mosquitoes were also less diverse and numerous in sites where chimpanzees were nesting as compared to those where they were feeding.These observations suggest that the sites where chimpanzees build their nests every night might be selected, at least in part, in order to minimize contact with anopheline mosquitoes, which might lead to a reduced risk in acquiring malaria infections.
N.Eshghy,A.Mesghali,Gh. Behbahani,M.Motabar
Iranian Journal of Public Health , 1973,
Abstract: A field trial evaluation of Sumithion (OMS-43) was carried out (1972) in the Mamasani area, Kazeroun, Southern Iran, in order to evaluate the effectiveness of this insecticide for the control of adult anopheline mosquitoes.The technical difficulties encountered in the area and related to malaria were the resistance of A. stephensi to DDT and Dieldrin, the exophilic and exophagic habits of A. d’thali, A. superpictus and A. fluviatilos and the ecology of the inhabitants.Sumithion spraying, wdp, 2 g/m2, covered 57 villages with a population of 11,445.One round of spraying was implemented in August at the peak of activity of A. stephensi. The effectiveness of Sumition was evaluated by pyrethrum spray, exit trap, night bait and outdoor ollections, as well as by age determination of female mosquitoes and biological evaluation.Pyrethrum spray catches showed a remarkable reduction in indoor resting density of A. stephensi. Exit trap observations indicated 100% mortality within a 24- hour recovery period. The man biting rate was reduced during the course of collection. On the basis of the results obtained, it was concluded that Sumithion is an effective insecticide against anopheline mosquitoes and controls A. stephensi, under the conditions of this experiment, for about two months.
Relationships between anopheline mosquitoes and topography in West Timor and Java, Indonesia
Ermi Ndoen, Clyde Wild, Pat Dale, Neil Sipe, Mike Dale
Malaria Journal , 2010, DOI: 10.1186/1475-2875-9-242
Abstract: Study areas were selected in three topographic types in West Timor and Java. These were: coastal plain, hilly (rice field) and highland. Adult mosquitoes were captured landing on humans identified to species level and counted.Eleven species were recorded, four of which were significant for malaria transmission: Anopheles aconitus, Anopheles barbirostris, Anopheles subpictus and Anopheles sundaicus. Each species occupied different topographies, but only five were significantly associated: Anopheles annularis, Anopheles vagus and Anopheles subpictus (Java only) with hilly rice fields; Anopheles barbirostris, Anopheles maculatus and Anopheles subpictus (West Timor only) with coastal areas.Information on significant malaria vectors associated with specific topography is useful for planning the mosquito control aspect of malaria management.Malaria is a life-threatening disease in Indonesia with an estimated 15 million cases and 42,000 deaths annually [1-3]. Malaria is transmitted by Anopheles mosquitoes. Of the 24 Anopheles species recorded in Indonesia, ten are major malaria vectors [4-6]. These include: Anopheles aconitus, Anopheles balabacensis, Anopheles barbirostris, Anopheles farauti, Anopheles koliensis, Anopheles letifer, Anopheles maculatus, Anopheles punctulatus, Anopheles subpictus and Anopheles sundaicus [5]. The most extensively occurring malaria vectors in Indonesia are An. sundaicus, An. subpictus, An. barbirostris, An. maculatus, An. aconitus, and An. balabacensis [5,7]. Anopheles sundaicus is associated with coastal, brackish water and is widely distributed from Sumatra through Java to Bali [8]. On Sumatra, however, it is regularly associated with fresh water [9]. Species recorded as important in Java include: An. subpictus [10,11]; An. aconitus, associated with rice-paddies, [8,10,12] and, in Central Java, according to Barcus et al [13], An. sundaicus is the dominant vector in coastal areas, and An. aconitus and An. barbirostris are often found in the c
Mosquito immune responses and compatibility between Plasmodium parasites and anopheline mosquitoes
Giovanna Jaramillo-Gutierrez, Janneth Rodrigues, Georges Ndikuyeze, Michael Povelones, Alvaro Molina-Cruz, Carolina Barillas-Mury
BMC Microbiology , 2009, DOI: 10.1186/1471-2180-9-154
Abstract: Four new An. gambiae (G3) genes were identified that, when silenced, have a different effect on P. berghei (Anka 2.34) and P. falciparum (3D7) infections. Orthologs of these genes, as well as LRIM1 and CTL4, were also silenced in An. stephensi (Nijmegen Sda500) females infected with P. yoelii (17XNL). For five of the six genes tested, silencing had the same effect on infection in the P. falciparum-An. gambiae and P. yoelii-An. stephensi parasite-vector combinations. Although silencing LRIM1 or CTL4 has no effect in An. stephensi females infected with P. yoelii, when An. gambiae is infected with the same parasite, silencing these genes has a dramatic effect. In An. gambiae (G3), TEP1, LRIM1 or LRIM2 silencing reverts lysis and melanization of P. yoelii, while CTL4 silencing enhances melanization.There is a broad spectrum of compatibility, the extent to which the mosquito immune system limits infection, between different Plasmodium strains and particular mosquito strains that is mediated by TEP1/LRIM1 activation. The interactions between highly compatible animal models of malaria, such as P. yoelii (17XNL)-An. stephensi (Nijmegen Sda500), is more similar to that of P. falciparum (3D7)-An. gambiae (G3).Mosquitoes transmit many infectious diseases, including malaria, lymphatic filariasis, yellow fever, and dengue. Among these diseases, malaria is by far the most costly in terms of human health. It is endemic to more than 100 countries and causes 550 million cases per year, with the highest mortality in children from sub-Saharan Africa. Malaria transmission to humans requires a competent mosquito species, as Plasmodium parasites must undergo a complex developmental cycle and survive the defense responses of their insect host. In Africa, Anopheles gambiae is the major vector of Plasmodium falciparum infection, which causes the most aggressive form of human malaria.The Plasmodium berghei (murine malaria) model is one of the most widely used experimental systems to study ma
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