白纹伊蚊溴氰菊酯抗性和敏感品系羧酸酯酶性质比较

本文对白纹伊蚊Aedes albopictus溴氰菊酯抗性品系和敏感品系羧酸酯酶的生物化学性质进行了比较。白纹伊蚊抗性品系和敏感品系羧酸酯酶随底物浓度(α-乙酸萘酯或β-乙酸萘酯)的变化比活力变化趋势一致,但抗性品系对这2种底物的比活力均高于敏感品系,抗性品系羧酸酯酶的米氏常数和最大反应速度与敏感品系有显著差异。胆碱酯酶抑制剂测定结果表明,抗性品系羧酸酯酶对敌敌畏和磷酸三苯酯的敏感性高于敏感品系,对残杀威的敏感性低于敏感品系。2个品系羧酸酯酶对脱叶磷的敏感性差异不大。说明羧酸酯酶可能与白纹伊蚊对溴氰菊酯抗性有关。     

Effects of extracellular calcium concentration on protein synthesis in Aedes albopictus cells

The influence of extracellular calcium concentration on mosquito cells was investigated in Aedes albopictus cells cultured in a medium with different amounts of calcium. Protein synthesis in cells incubated in low calcium culture medium was inhibited when compared to control cells. This inhibition was reversed by addition of calcium to the culture medium. Two calcium-induced proteins of approximately 70,000 and 80,000 daltons were detected when calcium was added to the extracellular medium of cells incubated in low calcium medium for longer than 2 h. Northern-blot analysis indicated that Hsp70 (heat shock protein of 70,000 dalton) specific mRNA is present in cells that were cultured in low calcium medium suggesting that the 70,000 dalton protein is a member of the Hsp70 family. Our results indicate that extracellular calcium concentration can modify the gene expression pattern in A. albopictus cells and the absence of calcium in the culture medium could be considered a stress factor. Arch. Insect Biochem. Physiol. 39:47–54, 1998. © 1998 Wiley-Liss, Inc.     

Pyrethroid resistance in Aedes aegypti and Aedes albopictus from Port‐au‐Prince,Haiti

In Port‐au‐Prince, Haiti, the status of insecticide resistance has not recently been evaluated for Aedes aegypti (L) and Aedes albopictus (Skuse) populations. No prophylactics exist for dengue, so prevention is only through vector control methods. An earthquake occurred in Haiti on January 12, 2010, with a magnitude of 7.0 Mw that devastated the area. Dengue became a major concern for the humanitarian relief workers that entered the country. Bottle bioassays were conducted in the field on adult mosquitoes reared from larvae collected from the grounds of the U.S. Embassy and from an adjacent neighborhood in eastern Port‐au‐Prince, Haiti. At the CDC, Fort Collins, CO, bioassays, molecular, and biochemical assays were performed on mosquitoes reared from field‐collected eggs. A small percentage of the population was able to survive the diagnostic dose in bioassays run in Haiti. Mosquitoes tested at the CDC demonstrated no phenotypic resistance. A variety of factors could be responsible for the discrepancies between the field and lab data, but temperature and larval nutrition are probably most important. Knowledge of localized resistance and underlying mechanisms helps in making rational decisions in selection of appropriate and effective insecticides in the event of a dengue outbreak.     

白纹伊蚊和埃及伊蚊经卵传递登革病毒的研究

白纹伊蚊和埃及伊蚊通过吸食病毒液或叮吸有病毒血症的小鸡血后,能感染登革１－４型病毒,并能在蚊体内增殖,对感染雌蚊了１和子２代幼虫,雌性或雄性成虫４５５９只,分１０１批进行了病毒检测,白纹伊蚊子１代的批阳性率;登革１型为１０％（１／１０）２型为２２．２２％（２／９）３型为３３．３３％（４／１２）,４型为２８．９５％（１１／３８）登革１～４型的最低子代感染率依次主国０．２０％,０．７１％,０．７０％和     

白纹伊蚊和埃及伊蚊对基孔肯雅病毒的易感性和传播性的研究

用４株基孔肯雅病毒经口感染白纹伊蚊和埃及伊蚊,进行了易感性和传播性的研究。结果表明,这两种蚊虫对基孔肯雅病毒易感。无论白纹伊蚊或埃及伊蚊,感染后第５－６天即可通过吸血将病毒传播给乳鼠,至第８－１３天,传播率可高达５５．５５％－１００％。感染蚊亦可经叮咬将病毒传播给小鸡。埃及伊蚊的易感性和传播率高于白纹伊蚊。实验还发现,不同来源毒株之间存在一定差异,如分离自云南白纹伊蚊的Ｍ８１株的感染率和传播率均高于其它毒株。这些结果表明,白纹伊蚊和埃及伊蚊在基孔肯雅病毒的保存和传播中起重要作用。     

Demographic and environmental factors associated with the distribution of Aedes albopictus in Cameroon

Aedes-transmitted arboviruses have spread globally due to the spread of Aedes aegypti and Aedes albopictus. Its distribution is associated with human and physical geography. However, these factors have not been quantified in Cameroon. Therefore, the aim was to develop an Ae. albopictus geo-referenced database to examine the risk factors associated with the vector distribution in Cameroon. Data on the Ae. albopictus presence and absence were collated and mapped from studies in published scientific literature between 2000 and 2020. Publicly available earth observation data were used to assess human geography, land use and climate risk factors related to the vector distribution. A logistic binomial regression was conducted to identify the significant risk factors associated with Ae. albopictus distribution. In total, 111 data points were collated (presence = 87; absence = 24). Different data collection methods and sites hindered the spatiotemporal analysis. An increase of one wet month in a year increased the odds of Ae. albopictus presence by 5.6 times. One unit of peri-urban area increased the odds by 1.3 times. Using publicly available demographic and environmental data to better understand the key determinants of mosquito distributions may facilitate appropriately targeted public health messages and vector control strategies.     

Herpetomonas,with Bacterium-like Inclusions,in Malaysian Aedes aegypti and Aedes albopictus*

SYNOPSIS Herpetomonas sp. was found repeatedly in the Malpighian tubules of laboratory-reared male and female Aedes aegypti and Aedes albopictus in Malaysia. The flagellates occurred irregularly, in batches, and were absent during long periods. The data suggest an exogenous source of infection for the mosquitoes, presumably from another insect, probably of another genus. Thirty to 40% of the flagellates of Aedes contained intracytoplasmic rod-shaped structures strongly resembling bacteria. These were found often in groups suggesting intracellular multiplication. They were passed to the Herpetomonas daughter cells during division. Parasitism of Aedes by Herpetomonas is extremely unusual, only one previous record, an inconclusive one, having been found. Parasitism by Herpetomonas containing bacterium-like rods has apparently never been reported.     

Effects of temperature and diet on development and interspecies competition in Aedes aegypti and Aedes albopictus

We asked whether climate change might affect the geographic distributions of Aedes aegypti (L.) and Aedes albopictus (Skuse) (Diptera: Culicidae). We tested the effects of temperature, diet and the presence of congeneric species on the performance of immature stages of these two aedine species in the laboratory. Mosquitoes in three different species-density combinations were reared at four constant temperatures (20 °C, 25 °C, 30 °C, 35 °C) on low- or high-level diets. Of the four temperatures tested, mortality increased only at 35 °C in both species. Mortality was higher on the high-level diet than on the low-level diet at 35 °C, but not at other temperatures. The presence of congeneric species had a significant positive effect on mortality in Ae. albopictus, but not in Ae. aegypti. Both species developed more quickly at higher temperatures within the range of 20-30 °C; development was not enhanced at 35 °C. Population growth of Ae. albopictus was more stable, regardless of diet and temperature; that of Ae. aegypti varied more according to these two factors. These species-specific attributes may help to explain the latitudinal distribution of the mosquitoes and degree of species dominance where they are sympatric.     

First record and establishment of the mosquito Aedes albopictus in Spain

The invasive mosquito Aedes (Stegomyia) albopictus (Skuse) (Diptera: Culicidae) was detected for the first time in Spain, in Sant Cugat del Vallès, a city in the north-east of the country (41 degrees 28' N, 2 degrees 4' E, altitude 120 m), during August 2004. A male and one larva were collected in the backyard of a house and in a tree hole, respectively. Dense populations of adults and larvae were found in subsequent surveys, confirming the establishment of the species in the area. This is the first report of the establishment of this species in the Iberian Peninsula.     

Frequency of pyrethroid resistance in Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in Thailand

Thirty‐two Aedes aegypti populations collected throughout Thailand and five populations of Aedes albopictus from southern Thailand were subjected to standard WHO contact bioassays to assess susceptibility to three commonly used synthetic pyrethroids: permethrin, deltamethrin, and lambda‐cyhalothrin. A wide degree of physiological response to permethrin was detected in Ae. aegypti, ranging from 56.5% survival (Lampang, northern Thailand) to only 4% (Kalasin in northeastern and Phuket in southern Thailand). All 32 populations of Ae. aegypti were found to have evidence of incipient resistance (62.5%) or levels of survival deemed resistant (37.5%) to permethrin. Four populations of Ae. albopictus were found with incipient resistance (97 – 80% mortality) and one with resistance (< 80%) to permethrin. The majority of Ae. aegypti populations (68.7%) was susceptible (> 98% mortality) to deltamethrin, with incipient resistance (observed 97–82% mortality) in other localities. In contrast, all populations of Ae. aegypti were completely susceptible (100% mortality) to the recommended operational dosage of lambda‐cyhalothrin. All five populations of Ae. albopictus were found completely susceptible to both deltamethrin and lambda‐cyhalothrin. Evidence of defined incipient or resistance to synthetic pyrethroids mandates appropriate response and countermeasures to mitigate further development and spread of resistance. In light of these findings, we conclude that routine and comprehensive susceptibility monitoring of dengue mosquito vectors to synthetic pyrethroids should be a required component of resistance management policies and disease control activities.     

State‐wide survey of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in Florida

Aedes aegypti and Aedes albopictus are invasive mosquito species with geographic ranges that have oscillated within Florida since their presence was first documented. Local transmission of dengue, chikungunya, and Zika viruses serves as evidence of the public health importance of these two species. It is important to have detailed knowledge of their distribution to aid in mosquito control efforts and understand the risk of arbovirus transmission to humans. Through a partnership involving the University of Florida Institute of Food and Agricultural Sciences Cooperative Extension Service and the Florida Medical Entomology Laboratory; the Florida Department of Health; and mosquito control agencies throughout Florida, a container mosquito surveillance program involving all life stages was launched in the summer of 2016 to detect the presence of Ae. aegypti and Ae. albopictus. Results from this survey were mapped to provide a picture of the current known distribution of Ae. aegypti and Ae. albopictus in Florida. Aedes aegypti and/or Ae. albopictus were detected in the 56 counties that were part of the survey. Only Aedes albopictus was detected in 26 counties, primarily in the panhandle region of Florida. The results of this work underscore the importance of maintaining container mosquito surveillance in a state where chikungunya, dengue, and Zika viruses are present and where there is continued risk for exotic arbovirus introductions.     

Oviposition by Aedes aegypti and Aedes albopictus: Influence of congeners and of oviposition site characteristics

We investigated the oviposition behavior of Ae. aegypti and Ae. albopictus. In particular we examined whether small‐scale site characteristics and the presence of conspecifics or congeners altered oviposition by these mosquitoes. Various combinations of females of the two species were allowed to oviposit inside cages among either vegetation (potted plants) or structural components (wood and concrete blocks). Numbers of eggs deposited per female were compared between species, sides, and treatments. Most significant differences between treatments and species involved differences between single species and mixed species treatments. Ae. aegypti deposited more eggs/female in the vegetation side than in the structure side whereas the opposite pattern was evident for Ae. albopictus. Ae. aegypti females had higher frequency of skip oviposition than Ae. albopictus. An average of 63% of the containers in the two‐species treatments contained eggs of both species, with more frequent joint occurrences observed in the treatment with three females of each species than in the treatments with one of each. Our results point to the existence of various interactions between gravid Ae. aegypti and Ae. albopictus females at or near the oviposition sites but further experimental work is necessary to fully characterize the interactions and their specific mechanisms.     

不同植物浸液对白纹伊蚊的产卵引诱作用

应用孕卵蚊虫粘捕法现场测试不同植物浸液对白纹伊蚊Aedes albopictus(Skuse)的产卵引诱作用,发现樟树叶、黄杨叶、狗尾草、绊根草、玉兰叶和竹叶的浸液现场诱蚊效果与自来水对照没有显著的差异;竹叶、玉兰叶、狗尾草和绊根草室内发酵21、30和45d的现场诱蚊效果没有显著的差异,而应用诱卵器法显示:竹叶、玉兰、狗尾草、绊根草植物浸液和自来水对照的诱卵数却差异显著。现场试验发现自来水、室外积水和蚊虫饲养水对白纹伊蚊的引诱效果没有显著的差异。     

Sodium channel gene expression in mosquitoes, Aeries albopictus （S.）

A mosquito strain of Aedes albopictus, HAmAal^G0, from Huntsville, Alabama, USA, showed a normal susceptibility and low tolerance to permethrin and resmethrin （pyrethroid insecticides） compared to a susceptible Ikaken strain, even though these pyrethroid insecticides have been used in the field for a long period of time in Alabama. Recently, we treated HAmAal^G0 in the laboratory with permethrin for five generations and detected no significant change in the level of resistance to permethrin in the selected mosquitoes, HAmAal^G0, compared with the parental strain HAmAal^G0. We then examined the allelic expression at the L-to-F kdr site of the sodium channel gene in the Aedes mosquitoes to address our hypothesis that the L-to-F kdr mutation was not present in HAmAal^G0 and HAmAal^G5 mosquitoes. We found that every tested individual in Ikaken, HAmAal^G5, and HAmAal^G5 populations expressed a codon of CTA at the L-to-F kdr site encoding Leu, strongly corresponding to their susceptibility to insecticides.     

Adaptation of the BG-Sentinel trap to capture male and female Aedes albopictus mosquitoes

In recent years, the remarkable spread of Aedes albopictus (Skuse) (Diptera: Culicidae) throughout the world has drawn attention to this hitherto poorly studied species, particularly after its role in outbreaks of chikungunya fever in the western Indian Ocean and in Italy. Variants of sterile insect technique (SIT), including the release of transgenic males with a dominant lethal gene (RIDL), have been proposed in the search for new and innovative methods of control. Knowledge of male dispersal, mating behaviour and longevity will be critical to the success of this approach. We present an effective and practical method for trapping both male and female Ae. albopictus using a mouse-baited BG-Sentinel trap.     

Isolation of microsatellite markers in the tiger mosquito Aedes albopictus (Skuse)

Among the numerous molecular markers available in population genetics, microsatellites are one of the most powerful tools developed in recent years. This paper describes the isolation of six polymorphic microsatellite loci in the tiger mosquito Aedes albopictus using an enriched genomic library technique. Such loci should be an efficient tool in population genetic studies for this mosquito species.     

The effect of photoperiod on life history and blood‐feeding activity in Aedes albopictus and Aedes aegypti (Diptera: Culicidae)

Several studies have examined how climatic variables such as temperature and precipitation may affect life history traits in mosquitoes that are important to disease transmission. Despite its importance as a seasonal cue in nature, studies investigating the influence of photoperiod on such traits are relatively few. This study aims to investigate how photoperiod alters life history traits, survival, and blood‐feeding activity in Aedes albopictus (Skuse) and Aedes aegypti (Linnaeus). We performed three experiments that tested the effects of day length on female survival, development time, adult size, fecundity, adult life span, and propensity to blood feed in Ae. albopictus and Ae. aegypti. Each experiment had three photoperiod treatments: 1) short‐day (10L:14D), 2) control (12L:12D), and 3) long‐day (14L:10D). Aedes albopictus adult females were consistently larger in size when reared in short‐day conditions. Aedes aegypti adult females from short‐day treatments lived longer and were more likely to take a blood meal compared to other treatments. We discuss how species‐specific responses may reflect alternative strategies evolved to increase survival during unfavorable conditions. We review the potential impacts of these responses on seasonal transmission patterns, such as potentially increasing vectorial capacity of Ae. aegypti during periods of shorter day lengths.     

Wolbachia modulates Chikungunya replication in Aedes albopictus

The Aedes albopictus mosquito has been involved as the principal vector of recent major outbreaks due to the chikungunya virus (CHIKV). The species is naturally infected by two strains of Wolbachia (wAlbA and wAlbB). Wolbachia infections are thought to have spread by manipulating the reproduction of their hosts; cytoplasmic incompatibility is the mechanism used by Wolbachia to invade natural populations of many insects including Ae. albopictus. Here, we report a study on the effects of removing Wolbachia from Ae. albopictus on CHIKV replication and examine the consequences of CHIKV infection on some life‐history traits (survival and reproduction) of Wolbachia‐free Ae. albopictus. We found that Wolbachia‐free mosquitoes maintained a highly heterogeneous CHIKV replication compared to Wolbachia‐infected individuals. In Wolbachia‐infected Ae. albopictus, the regular increase of CHIKV followed by a steady viral load from day 4 post‐infection onwards was concomitant with a decline in Wolbachia density. This profile was also detected when examining the two key organs for viral transmission, the midgut and the salivary glands. Moreover, Wolbachia‐free Ae. albopictus was not altered in life‐history traits such as survival, oviposition and hatching characteristics whether infected or not with CHIKV. We found that Wolbachia is not essential for viral replication, its presence could lead to optimize replication from day 4 post‐infection onwards, coinciding with a decrease in Wolbachia density. Wolbachia may regulate viral replication in Ae. albopictus, with consequences on survival and reproduction.     

Satellite observation to assess dengue risk due to Aedes aegypti and Aedes albopictus in a subtropical city of Argentina

Earth observation environmental features measured through remote sensing and models of vector mosquitoes species Aedes aegypti and Ae. albopictus provide an advancement with regards to dengue risk in urban environments of subtropical areas of Argentina. The authors aim to estimate the effect of landscape coverage and spectral indices (Normalized Difference Vegetation Index [NDVI], Normalized Difference Water Index [NDWI] and Normalized Difference Built-up Index [NDBI]) on the larvae abundance of Ae. aegypti and Ae. albopictus in Eldorado, Misiones, Argentina using remote satellite sensors. Larvae of these species were collected monthly (June 2016 to April 2018), in four environments: tire repair shops, cemeteries, dwellings and an urban natural park. The proportion of landscape coverage (water, urban areas, bare soil, low vegetation and high vegetation) was determined from the supervised classification of Sentinel-2 images and spectral indices, calculated. The authors developed spatial models of both vector species by generalized linear mixed models. The model's results showed that Ae. aegypti larvae abundance was better modelled by NDVI minimum values, NDBI maximum values and the interaction between them. For Ae. albopictus proportion of bare soil, low vegetation and the interaction between both variables explained better the abundance.