上海市中心城区成蚊种群动态及新变化研究

为全面掌握上海中心城区蚊虫种群动态及新变化,选取城区蚊虫较易出现的公园和绿化区域环境类型（人民广场及人民公园地区）,采用CO：诱捕法进行连续超过220d的成蚊动态监测研究。结果显示,2012年224d共捕捉到蚊虫20826头,包括3属6种;淡色库蚊和白纹伊蚊为上海中心城区优势蚊种（构成比分别为71．8％和19．7％）;不同蚊种季节分布差异性显著,淡色库蚊和白纹伊蚊高峰期分别位于5～6月和7～8月,且整体上淡色库蚊密度高于白纹伊蚊（除8月下旬外,其余均P〈0．05）,三带喙库蚊在7月中下旬显著上升（分别为681和580头／旬）;蚊虫13变化趋势波动幅度较大,在相同的月份或季节亦出现较大日变化差异;将2008～2011年历史监测数据与2012年进行趋势比较,仅个别年份间有显著相关性：不同年份间的旬分布亦存在统计学差异。本研究提示,上海市中心城区的优势蚊种仍为淡色库蚊和白纹伊蚊,该两种蚊种的季节分布与某些文献报道存在差异,主要由上海城区的气候特点决定;上海城区的蚊媒防治工作仍应针对这两种蚊虫的季节分布采取针对性的有效防控措施,此外三带喙库蚊对城市环境的适应性不断提高,为上海城区的蚊媒防治工作提出了新的挑战。     

广东省佛山市某镇白纹伊蚊密度季节消长情况调查分析

目的了解和掌握佛山市某镇白纹伊蚊的季节消长情况,为当地开展登革热防控工作提供依据。方法用诱捕器进行4d为一周期的成蚊诱捕以及诱卵现场实验,并根据季节的诱捕结果估算白纹伊蚊的密度消长情况。结果 2008年秋季至2009年夏季,4次实验共捕获成蚊282只,包括白纹伊蚊161只;收集蚊卵5954个。实验结果显示四个季度之间蚊媒密度的差异具有统计学意义。其中,诱蚊诱卵指数（MOI）（χ2=52.172,P〈0.000）,诱蚊指数（MI）（χ2=47.664,P〈0.000）,诱卵指数（OI）（χ2=44.525,P〈0.000）,诱蚊密度指数（MDI）（F=17.448,P〈0.000）,蚊卵密度指数（EDI）（F=13.454,P〈0.000）。结论当地白纹伊蚊夏秋两季的阳性指数与密度指数均比冬春两季高且差异具有统计学意义。其中,夏末秋初是蚊媒密度的高峰。本次实验结果与传统监测指标所反映的密度变化趋势一致。     

16S rRNA gene sequences from bacteria associated with adult Anopheles darlingi (Diptera: Culicidae) mosquitoes

The microbial flora associated with Anopheles darlingi Root (Diptera: Culicidae), a major Neotropical malaria vector, was investigated for the development of a paratransgenesis-based approach to control malaria transmission in Brazil. Female mosquitoes were collected using human land catches and captured insects provided a bloodmeal. The controlled blood feeding resulted in increased detection of mosquito bacterial population because it was possible to retrieve bacterial DNA from all blood-fed mosquitoes. The 16S sequences of bacteria recovered, include some closely related to those found in other vector mosquitoes, including Aeromonas, Pantoea and Pseudomonas species.     

Japanese encephalitis virus in Bangkok: factors influencing vector infections in three suburban communities.

An unexpected outbreak of Japanese encephalitis (JE) in Bangkok in 1985 led us to investigate the vector ecology of urban JE from January 1986 to June 1987 at three suburban sites that displayed a wide range of factors imputed to influence JE transmission. Culex tritaeniorhynchus Giles and Cx. gelidus Theobald, suspected vectors, comprised 71-96% of all mosquitoes collected by CO2-baited CDC traps at the three sites. Mean of mosquito abundance per two trap-nights per month ranged from 28 to 5,728 mosquitoes at the sites of lowest and highest abundance, respectively. Cx. tritaeniorhynchus yielded more JE isolates (n = 16) than Cx. gelidus (n = 7), but the minimum infection rates of the two species (number of JE isolates per 1,000 mosquitoes tested; MIR, 0.17 and 0.47, respectively) were comparable and covaried with vector abundance. Moreover, the proportion of sentinel pigs that had JE antibodies generally increased proportionately with vector abundance at the sites. Vector abundance was high in monsoon (May-October), moderate in transition (March-April and November-December), and low in dry (January-February) seasons. Mosquitoes collected in monsoon seasons yielded 96% of the JE isolates, whereas 4 and 0% of the isolates were obtained from transition and dry season collections, respectively. More pigs seroconverted in monsoon and transition seasons than in dry seasons. Indices of JE transmission activity (vector abundance, pig seroconversions, and MIRs) increased proportionately with rainfall. Despite higher indices at the site of greatest vector abundance than elsewhere, the risk of human infection appeared greatest at the site with moderate vector abundance because of its greatest human population density.     

Seasonal distribution, biology, and human attraction patterns of culicine mosquitoes (Diptera: Culicidae) in a forest near Puerto Almendras, Iquitos, Peru

This study was conducted as part of a field ecology study of arboviral activity in the Amazon Basin, Peru, to determine the taxonomy, frequency, seasonal, and vertical distributions of potential mosquito vectors. In addition, the relative efficiency of human-landing collections and dry ice-baited Centers for Disease Control (CDC)-type light traps was determined for collecting mosquitoes. A total of 70 species of mosquitoes from 14 genera were collected from June 1996 through December 1997 at a forested site near Puerto Almendras, approximately 20 km west-southwest of Iquitos, Peru. Three species [Psorophora (Janthinosoma) albigenu (Peryassu), Ochlerotatus (Ochlerotatus) fulvus (Wiedemann), and Ochlerotatus (Ochlerotatus) serratus (Theobald)] accounted for 70% of all mosquitoes captured in human-landing collections. Overall, biting activity occurred throughout the 24-h cycle but was higher during the daytime, primarily because of large populations of two day-biting species, Ps. albigenu and Oc. serratus. Oc. fulvus was active throughout the 24-h cycle but was more frequently collected during the evening. Oc. fulvus, Ps. albigenu, Culex (Melanoconion) pedroi Sirivanakarn & Belkin, and a mixture of Culex (Melaonoconion) vomerifer Komp, and Culex (Melanoconion) gnomatos Sallum, Huchings & Ferreira, accounted for 73% of the mosquitoes captured during darkness) by human collectors. In general, Ochlerotatus spp. and Psorophora spp. were more commonly captured in human-landing collections, whereas most Culex spp. were more frequently collected in the dry ice-baited CDC-type light traps. In general, mosquito populations were lowest from June through August when river levels were at their lowest. Two large population peaks occurred in November-December and in February-March as a result of "flood water" mosquito populations (e.g., Ps. albigenu). These data provide a better understanding of the taxonomy, population density, and seasonal distribution of potential mosquito vectors within the Amazon Basin region and allow for the development of appropriate vector and disease prevention strategies.     

Bioecology and vectorial capacity of Aedes albopictus (Diptera: Culicidae) in Macao, China, in relation to dengue virus transmission

Until 2001, the Chinese Territory of Macao had not registered any autochthonous dengue cases, despite the abundance of Aedes albopictus (Skuse), a known vector. This work describes a bioecological characterization of the local Ae. albopictus adult population, with the purpose of estimating the receptivity of Macao to dengue introduction. In the wet seasons of 1997 and 1998 and the dry season of 1998, Ae. albopictus was the most abundant human-biting mosquito. Daily biting rates of 314 mosquitoes per person were recorded in the wet season with a reduction to 94 in the dry season. Ae. albopictus was mainly exophagic and exophilic and had a human blood index of 44%. The parity rate of field-collected mosquitoes was 57%. Daily survival rate ranged from 91 to 97%. Estimates of vectorial capacity ranged from 144 to 880, depending on what parameter values were used. These estimates indicated a great receptivity for the introduction of dengue viruses, as the 2001 outbreak came to prove.     

新疆中哈边境阿拉山口口岸蚊虫调查研究

为了解中哈边境阿拉山口口岸地区蚊虫种群本底构成及生态习性,采用帐诱、挥网、灯诱采集蚊虫,进行形态学分类鉴定.2012与2013两年共采集成蚊16 317只、经随机抽样鉴定3 370只,隶属2科5属11种.2013年比2012年增加了2种,比历史资料记录的增加了5种,其中凶小库蚊占蚊虫总数的46.0％,为当地优势种.其生境季节变化从3月开始活动,5月达到高峰,8月为次高峰,至11月活动消失.调查结果显示应重视对优势蚊种的防控及携带病原的研究,识别外来物种的入侵、蚊媒疾病的监控提供了基础资料.     

Evaluation of methods for sampling the malaria vector Anopheles darlingi (Diptera, Culicidae) in Suriname and the relation with its biting behavior

The effectiveness of CO2-baited and human-baited mosquito traps for the sampling of Anopheles darlingi Root was evaluated and compared with human landing collections in Suriname. Biting preferences of this mosquito on a human host were studied and related to trapping data. Traps used were the Centers for Disease Control and Prevention Miniature Light trap, the BG Sentinel mosquito trap, the Mosquito Magnet Liberty Plus mosquito trap (MM-Plus), and a custom-designed trap. Carbon dioxide and humans protected by a bed net were used as bait in the studies. The number of An. darlingi collected was greater with human landing collections than with all other collection methods. An. darlingi did not show a preference for protected humans over CO2 bait. The BG Sentinel mosquito trap with CO2 or human odor as bait and the MM-Plus proved the best alternative sampling tools for An. darlingi. The BG Sentinel mosquito trap with CO2 or human odor as bait was also very efficient at collecting Culex spp. In a field study on biting preferences of wild An. darlingi, the females showed directional biting behavior (P < 0.001), with a majority of females (93.3%) biting the lower legs and feet when approaching a seated human host. Higher efficiency of the closer-to-the-ground collecting MM-Plus and BG Sentinel mosquito trap when compared with the other trapping methods may be a result of a possible preference of this mosquito species for low-level biting. It is concluded that odor-baited sampling systems can reliably collect An. darlingi, but the odor bait needs to be improved, for instance, by including host-specific volatiles, to match live human baits.     

云南丽江市自然风景区居民点蚊类多样性研究

为调查和了解云南省丽江市主要自然风景区蚊类多样性状况,应用灯诱法对丽江市虎跳峡、石鼓、黎明、宁蒗、拉市海、文笔海、程海、泸沽湖共8个自然风景区居民点夜间活动的成蚊进行调查取样,分类整理和统计分析. 结果共捕获蚊类 45 346只,发现蚊类2亚科4属28种. 其中, 库蚊属（Genus Culex）14种,按蚊属（Genus Anopheles）7 种,伊蚊属（Genus Aedes）6种,阿蚊属（Genus Armigeres）1种. 三带喙库蚊Culex tritaeniorhynchus为优势种（占83.80%）,中华按蚊Anopheles sinensis为常见种（占8.09%）,其余26种蚊子的数量相对较少（合计占8.12%）. 在8个风景区中,泸沽湖物种多样性（多样性指数1.7863）最高, 其次是虎跳峡（多样性指数1.6178）,而生态优势度和密度均都较低;反之,物种多样性最低为石鼓（多样性指数0.3649）,而其生态优势度指数和密度为最高. 结果表明丽江市自然风景区蚊类的组成较为丰富,三带喙库蚊和中华按蚊是优势种和常见种,优势种三带喙库蚊主导了当地风景区蚊类的生态优势度和物种多样性的变化趋势. 各风景区气候环境条件和周边耕作地类型对蚊类的群落结构、密度和物种多样性具有重要影响.研究认为,保护自然环境,改变周边农耕区耕作和种植类型,提高环境异质性,对抑制蚊类密度、提高蚊类群落和物种多样性具有重要意义.     

Two digestive trypsins occur in three species of neotropical anophelines

Trypsin activity increases in the midgut of Anopheles aquasalis, Anopheles albitarsis, and Anopheles darlingi after a bloodmeal. The activity returns to basal levels at the time the blood is completely digested. Affinity chromatography, reversed-phase high performance liquid chromatography (HPLC), and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were used to sequentially purify the mosquito trypsins found in the midguts at 24 h after feeding. Aminoterminal sequencing of the purified trypsins showed the occurrence of two distinct trypsins in the midgut of each of the mosquitoes studied. The sequences obtained are similar to those of the trypsins of other hematophagous insects.     

Monitoring temporal abundance and spatial distribution of Aedes polynesiensis using BG-Sentinel traps in neighboring habitats on Raiatea, Society Archipelago, French Polynesia

Adult numbers and sizes of mosquitoes were monitored for 2 yr in neighboring habitats on the western coast of Raiatea (Society Archipelago) in anticipation of testing new vector control technologies. Aedes polynesiensis Marks females comprised the overwhelming majority (approximately 99%) of the three species of mosquitoes captured in Biogent Sentinel traps placed at fixed sites on three small satellite islands (motus) of the western lagoon and on the shoreline of Raiatea. Aedes polynesiensis males, Aedes aegypti (L.), and Culex quinquefasciatus Say rarely were collected. Numbers of Ae. polynesiensis females per collection differed among trapping dates and locations, with the majority of females captured on two motus, Horea and Toamaro. Shoreline and Horea females had significantly longer mean wing lengths than females from Tiano and Toamaro. Thus, wing lengths were influenced more by local developmental conditions than overall numbers of adults. Significantly more females were captured during the wet season than the dry season. Nonetheless, at least on the two highly productive motus, dry-season females had larger wing lengths than their wet season counterparts. Local weather patterns predicted about half the variation in mosquito numbers. Differences in vector abundance observed when comparing neighboring motus are likely because of differences in human activity and mosquito suppression.     

Biodiversity and times of activity of mosquitoes (Diptera: Culicidae) in the biome of the Atlantic Forest in the State of Rio de Janeiro, Brazil

A temporal observational study on culicid entomofauna was conducted in a region characterized as a fragment of the Atlantic Forest that forms the Tinguá Biological Reserve in the State of Rio de Janeiro. This investigation was performed with the aim of analyzing the influence of climatic factors (temperature and relative air humidity) on the activity levels at different times of the day among mosquito species within the ecosystems that form the Tinguá Biological Reserve. The abundance index and dominance coefficient were calculated in relation to 61 mosquito species that were caught at four sampling sites, in the mornings, afternoons, and evenings. The results revealed that culicid species were distributed with greater incidence during the two diurnal periods and that their preference for times of the day was directly influenced by the climatic variables analyzed. The latter acted as limiting factors for occurrences of mosquito species.     

“三江并流”自然遗产地金沙江流域居民区蚊类物种多样性与多度空间分布格局及其关系

本文调查和探讨我国西南山地蚊类物种多样性与多度的空间分布格局及其关系.以滇西北“三江并流”自然遗产地金沙江流域(北纬26°00′～28°30′;东经99°00′～101°00′和海拔1 500～3 500 m之间)为调查研究的空间范围,应用灯诱法对16个乡镇居民区蚊类多样性进行调查取样、统计和分析.结果共捕获蚊类2亚科...     

Environmental predictors of the occurrence of ground water mosquito immatures in the Paraná Lower Delta, Argentina

Characterizing mosquito larval habitats is essential for understanding the complex interactions between immatures and the biotic and abiotic components of their environment. Using generalized linear mixed models, we studied the environmental predictors of the presence of three ubiquitous mosquito species breeding in ground water habitats in the Paraná Lower Delta, Argentina. During a year-round survey, 34.1% of the 419 ground water habitats inspected were positive for either Culex dolosus s.l. (Lynch Arribálzaga 1891), Aedes crinifer (Theobald 1903), or Culex intrincatus Brèthes 1916. Univariate analysis showed that the former two occurred throughout the year, whereas the latter during the summer and fall. Ae. crinifer and Cx. intrincatus were more frequently collected in secondary forests, whereas Cx. dolosus s.l. was homogeneously distributed among land uses. Best generalized linear mixed models included the sampling period and landscape variables in different combinations for each species. Spatial dependence of the data was evident for Cx. dolosus s.l. and Ae. crinifer. Our results showed that the most widespread species presented different spatio-temporal distribution patterns, related with land use, anthropic intervention, and seasonality, highlighting the complexity of the wetland under study. This methodological approach could aid in the selection of priority areas for vector control and disease risk management.     

Mosquito vectors of West Nile Fever in Israel

West Nile fever (WNF) is endemic in Israel. In 1999, country-wide adult mosquito surveys were initiated and intensified after the 2000 country-wide outbreak of WNF in humans. In 8 consecutive yr, groups of male and female specimens of different species and from different locations were tested for infection with West Nile virus (WNV). Three species made up >87% of the total catch: Culex pipiens L. (52%), with an infection rate (IR) of 0.5; Cx. perexiguus Theobald (20%), with an IR of 2.7; and Aedes caspius Pallas (15%), with an IR of 0.6. The geographical and temporal distribution of WNV-infected mosquitoes was similar but was not parallel to the seasonal abundance of the populations. The seasonal occurrence of human cases is in correlation with the finding of WNV-positive mosquito specimens reaching a peak 1 mo later than the mosquito peak. The relative importance of the mosquito species in the epidemiology of WNF is discussed. Cx. perexiguus is considered the major vector of WNF in Israel.     

Proboscis amputation facilitates the study of mosquito (Diptera: Culicidae) attractants, repellents, and host preference

Proboscis amputation has facilitated the study of mosquito behavior. Using humans as a host is very important in the study of mosquito attractants, repellents, and host preference. However, mosquito bites cause potential medical problems because of hypersensitivity and perhaps secondary bacterial infection, even using laboratory mosquitoes. Moreover, once a normal female mosquito bites and feeds on human blood, it cannot be used in subsequent probing tests. These problems were resolved by proboscis amputation. Variation of attraction among humans was examined effectively without bites using proboscis-amputated Aedes albopictus Skuse. Proboscis-amputated and normal mosquitoes also showed equal repellency against 1% L-lactic acid. Although the mosquitoes lacked the tip of the labium and some sensilla, they alighted on human forearms in the same way as normal mosquitoes. Because proboscis-amputated mosquitoes continued to probe avidly, they could be used repeatedly, thereby reducing the number of mosquitoes required for experimentation. The use of proboscis-amputated mosquitoes would promote various studies of mosquito attraction or repellency with no risk of hypersensitivity and secondary bacterial infection by mosquito bites.     

Malaria infection,morbidity and transmission in two ecological zones Southern Ghana

A one year survey was conducted in 1992 to compare malaria infection, morbidity and transmission patterns between a coastal savannah community (Prampram) and a community (Dodowa) in the forest zone in southern Ghana. The study population of 6682 at Prampram and 6558 at Dodowa were followed up in their homes once every two weeks and all episodes of clinical malaria recorded. Blood films for microscopy were prepared from 600 participants randomly selected in each community in April and in August representing dry and wet seasons respectively. Mosquitoes biting humans between 1800 hrs and 0600 hrs, as well as indoor and outdoor resting mosquitoes were collected weekly. All mosquitoes collected were classified into species and examined for sporozoites by dissection and ELISA. The incidence rate of clinical malaria was higher in Dodowa (106.6/1000 pop.) than in Prampram (68.5/1000 pop.) It was highest in < 10 year age groups in both communities. It was also higher in the wet season than in the dry season. The prevalence of patent parasitaemia at Prampram and Dodowa in April in the dry season. The prevalence of patent parasitaemia at Prampram and Dodowa in April 1992 was 19.8% (117/590) and 42.2% (253/599) respectively. The corresponding figures for August were 26.6%(160/602)at Prampram and 51.3% (309/602) at Dodowa. Plasmodium falciparum infection contributed 78-85% of the parasitaemia in April and 93-99% in August. The average man-biting rate for Anopheles gambiae s.l was higher at Prampram than at Dodowa (1.54 vs 0.79 bites/man/night) but the average sporozoite rate was higher at Dodowa than at Prampram (2% vs 0.7%). The peak of biting density at Prampram occurred in June whilst that of Dodowa occurred in November.     

Mosquito species abundance and diversity in Malindi,Kenya and their potential implication in pathogen transmission

Mosquitoes (Diptera: Culicidae) are important vectors of human disease-causing pathogens. Mosquitoes are found both in rural and urban areas. Deteriorating infrastructure, poor access to health, water and sanitation services, increasing population density, and widespread poverty contribute to conditions that modify the environment, which directly influences the risk of disease within the urban and peri-urban ecosystem. The objective of this study was to evaluate the mosquito vector abundance and diversity in urban, peri-urban, and rural strata in Malindi along the Kenya coast. The study was conducted in the coastal district of Malindi between January and December 2005. Three strata were selected which were described as urban, peri-urban, and rural. Sampling was done during the wet and dry seasons. Sampling in the wet season was done in the months of April and June to cover the long rainy season and in November and December to cover the short rainy season, while the dry season was between January and March and September and October. Adult mosquito collection was done using Pyrethrum Spray Collection (PSC) and Centers for Disease Control and Prevention (CDC) light traps inside houses and specimens were identified morphologically. In the three strata (urban, peri-urban, and rural), 78.5% of the total mosquito (n = 7,775) were collected using PSC while 18.1% (n = 1,795) were collected using the CDC light traps. Using oviposition traps, mosquito eggs were collected and reared in the insectary which yielded 329 adults of which 83.8% (n = 276) were Aedes aegypti and 16.2% (n = 53) were Culex quinquefasciatus. The mosquito distribution in the three sites varied significantly in each collection site. Anopheles gambiae, Anopheles funestus and Anopheles coustani were predominant in the rural stratum while C. quinquefasciatus was mostly found in urban and peri-urban strata. However, using PSC and CDC light trap collection techniques, A. aegypti was only found in urban strata. In the three strata, mosquitoes were mainly found in high numbers during the wet season. Further, A. gambiae, C. quinquefasciatus, and A. aegypti mosquitoes were found occurring together inside the houses. This in turn exposes the inhabitants to an array of mosquito-borne diseases including malaria, bancroftian filariasis, and arboviruses (dengue fever, Yellow fever, Rift Valley fever, Chikungunya fever, and West Nile Virus). In conclusion, our findings provide useful information for the design of integrated mosquito and disease control programs in East African environments.     

Strategies for controlling the epizootic amplification of arboviruses

A previously validated, spatially explicit, agent-based model of arbovirus transmission among vector mosquitoes and avian hosts is used to explore the effectiveness of different insecticide control strategies for reducing rates of epizootic transmission and mosquito infection. Mosquito control within the model reduces infection rates among hosts and vectors but generally lengthens the transmission season. Insecticide application focused at oviposition sites is found to be as effective as control applied over the entire model landscape. The findings also indicate that optimum use of insecticide resources would first target areas in which bird activity is collocated with vector mosquito breeding sites, and then, if resources permit and mosquito mortality due to the insecticide is high, target other vector mosquito breeding habitats. More broadly, these experiments demonstrate that model systems provide an economical framework for testing different mosquito and mosquito-borne pathogen control strategies and can ultimately inform field interventions and enable better allocation of intervention resources.     

Japanese encephalitis in Kerala, south India: can Mansonia (Diptera: Culicidae) play a supplemental role in transmission?

A 2-yr entomological study was carried out in Kerala, south India, to identify the mosquito vectors of Japanese encephalitis (JE) virus and to determine their seasonal abundance and infection. In total, 150,454 mosquitoes belonging to five genera and 18 species were collected from vegetation surrounding cattle sheds and pigsties in villages at dusk. Culex tritaeniorhynchus Giles (66.7%) was the most abundant species, with increases in numbers associated with rice cultivation. JE virus isolations were made from Cx. tritaeniorhynchus and Mansonia indiana Edwards. Based on high abundance and frequent JE virus infection, Cx. tritaeniorhynchus seems to be the most important vector, whereas Ma. indiana is probably a secondary vector.