三色迷彩油添加避蚊胺对白纹伊蚊驱避效果的实验室评价

参照中华人民共和国国家标准GB/T 17322.10-1998和《军队特需药品研发勤务技术指导原则(试行)》规定的测试方法,测试了避蚊胺和水溶性二氧化钛处理迷彩油(CFP)对白纹伊蚊Aedes albopictus的驱避效果,为研发我军专用的防蚊虫迷彩油提供依据。结果表明:在3种颜色迷彩油中加入DEET后,不影响DEET的驱蚊效果;添加不同浓度DEET对蚊虫的驱避效果差异显著,20%DEET和25%DEET+迷彩油对白纹伊蚊的平均防护时间均达到或超过10 h,达到《军队特需药品研发勤务技术指导原则(试行)》规定的标准,15%DEET+迷彩油平均防护时间不足10 h,未达《军队特需药品研发勤务技术指导原则(试行)》规定的标准。研究表明:将适量DEET与迷彩油混合涂抹于皮肤可能作为演习或战时的伪装和防蚊的一种有效的综合保护措施。     

Comparison of the insecticide susceptibilities of laboratory strains of Aedes aegypti and Aedes albopictus

A susceptible strain of Aedes albopictus derived from the Gainesville strain (Florida, USA) was established in our laboratory. The larvicidal efficacies of the neurotoxic insecticides temephos, permethrin and the pure cis and trans-permethrin isomers and the microbial insecticide Bacillus thuringiensis israelensis (Bti) against Ae. albopictus were estimated and compared to a susceptible strain of Aedes aegypti. The larvicidal effect of insect growth regulator pyriproxyfen was also evaluated in both mosquito strains. The median lethal concentration/median emergency inhibition values for Ae. aegypti and Ae. albopictus, respectively, were: temephos, 3.058 and 6.632 ppb, permethrin, 3.143 and 4.933 ppb, cis-permethrin, 4.457 and 10.068 ppb, trans-permethrin, 1.510 and 3.883 ppb, Bti, 0.655 and 0.880 ppb and pyriproxyfen, 0.00774 and 0.01642 ppb. Ae. albopictus was more tolerant than Ae. aegypti to all six larvicides evaluated. The order of susceptibility for Ae. aegypti was pyriproxyfen > Bti > trans-permethrin > temephos > permethrin > cis-permethrin and for Ae. albopictus was pyriproxyfen > Bti > trans-permethrin > permethrin > temephos > cis-permethrin. Because both species can be found together in common urban, suburban and rural breeding sites, the results of this work provide baseline data on the susceptibility of Ae. albopictus to insecticides commonly used for controlling Ae. aegypti in the field.     

Behavioral responses of Aedes aegypti,Aedes albopictus,Culex quinquefasciatus,and Anopheles minimus against various synthetic and natural repellent compounds

The behavioral responses of colony populations of Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles minimus to four essential oils (citronella, hairy basil, catnip, and vetiver), two standard repellents (DEET and picaridin), and two synthetic pyrethroids (deltamethrin and permethrin) were conducted in the laboratory using an excito‐repellency test system. Results revealed that Cx. quinquefasciatus and An. minimus exhibited much stronger behavioral responses to all test compounds (65–98% escape for contact, 21.4–94.4% escape for non‐contact) compared to Ae. aegypti (3.7–72.2% escape (contact), 0–31.7% (non‐contact)) and Ae. albopictus (3.5–94.4% escape (contact), 11.2–63.7% (non‐contact)). In brief, essential oil from vetiver elicited the greatest irritant responses in Cx. quinquefasciatus (96.6%) and An. minimus (96.5%) compared to the other compounds tested. The synthetic pyrethroids caused a stronger contact irritant response (65–97.8% escape) than non‐contact repellents (0–50.8% escape for non‐contact) across all four mosquito species. Picaridin had the least effect on all mosquito species. Findings from the current study continue to support the screening of essential oils from various plant sources for protective properties against field mosquitoes.     

猫薄荷精油有效成分的提取及其对白纹伊蚊、淡色库蚊的驱避活性

采用同时蒸馏萃取及硅胶柱层析法从猫薄荷Nepeta cataria 植物中提取、分离制得驱蚊有效成分假荆芥内酯,并采用个体涂肤有效保护时间测定法及风洞空间驱避效果测试法, 对假荆芥内酯与避蚊胺(DEET)的驱蚊效果进行了对比试验。结果表明,400 g新鲜猫薄荷植株可制得精油5.6 g,其中假荆芥内酯含量为55%,Z,E-假荆芥内酯32%, E,Z-假荆芥内酯23%。室内标准药效评价结果表明,DEET对白纹伊蚊Aedes albopictus 及淡色库蚊Culex pipiens pallens有效保护时间分别为9.6±0.2 h与11.5±1.5 h,而假荆芥内酯仅为2.2±0.2 h与4.3±0.8 h。风洞定向行为测试结果表明,假荆芥内酯单独作用时,对蚊虫有微弱的引诱效果,但在人体气味及二氯甲烷L-乳酸存在时,可显著抑制这些引诱物对蚊虫的引诱效果,是优良的空间驱避剂;DEET对蚊虫无明显的引诱作用,对二氯甲烷L-乳酸溶液引诱剂也无明显的抑制效果,但可显著增强人体气味对蚊虫的引诱性。     

Repellent effect of plant essential oils against Aedes albopictus.

Six essential oils: asteraceae oil, rutaceae oil, mentha piperta oil, carvacryl oil, citronella oil, and eucalyptus oil were tested for evaluation of their repellent effects against Aedes albopictus mosquitoes under laboratory conditions. Only citronella oil and eucalyptus oil were tested with human beings. There was considerable protection for mice. Carvacryl oil (7%) provided 100% protection for mice after 7 h. Eucalyptus oil (15%) gave protection to humans for least 3 h; the protection time was prolonged to 5 h after adding 5% vanillin. The mixture could be developed into a practical product after the field evaluation.     

Optimization of pyrethroid and repellent on fabrics against Stegomyia albopicta (=Aedes albopictus) using a microencapsulation technique

A new approach employing a combination of pyrethroid and repellent is proposed to improve the protective efficacy of conventional pyrethroid‐treated fabrics against mosquito vectors. In this context, the insecticidal and repellent efficacies of commonly used pyrethroids and repellents were evaluated by cone tests and arm‐in‐cage tests against Stegomyia albopicta (=Aedes albopictus) (Diptera: Culicidae). At concentrations of LD₅₀ (estimated for pyrethroid) or ED₅₀ (estimated for repellent), respectively, the knock‐down effects of the pyrethroids or repellents were further compared. The results obtained indicated that deltamethrin and DEET were relatively more effective and thus these were selected for further study. Synergistic interaction was observed between deltamethrin and DEET at the ratios of 5 : 1, 2 : 1, 1 : 1 and 1 : 2 (but not 1 : 5). An optimal mixing ratio of 7 : 5 was then microencapsulated and adhered to fabrics using a fixing agent. Fabrics impregnated by microencapsulated mixtures gained extended washing durability compared with those treated with a conventional dipping method. Results indicated that this approach represents a promising method for the future impregnation of bednet, curtain and combat uniform materials.     

The effect of inbreeding and larval feeding regime on immature development of Aedes albopictus

The fundamental approach to the biological control of Aedes albopictus requires the mass rearing of mosquitoes and the release of highly competitive adults in the field. As the fitness of adults is highly dependent on the development of immatures, we aimed to identify the minimum feeding regime required to produce viable and competitive adults by evaluating three response parameters: development duration, immature mortality, and adult wing length. Our study suggests at least 0.60 mg/larva/day of larval diet composed of dog food, dried beef liver, yeast, and milk powder in a weight ratio of 2:1:1:1 is required to maximize adult fitness. With standardized protocols in mass rearing, intensive studies can be readily conducted on mosquito colonies to facilitate comparisons across laboratories. This study also evaluated the differences in response of laboratory and field strains under different feeding regimes. We found that strain alone did not exert substantial effects on all response parameters. However, the field strain exhibited significantly lower immature mortality than the laboratory strain under the minimum feeding regime. Females and males of the laboratory strain had longer wing lengths under nutritional constraint due to the higher mortality that resulted in reduced interactions with the remaining larvae. Meanwhile, the field strain exhibited heterogeneous duration of immature development compared with the laboratory strain. The disparities demonstrated by the two strains in this study suggest the effect of inbreeding surfaced after a long term of laboratory colonization. Despite the trade‐offs resulting from laboratory colonization, the competitiveness of the laboratory strain of Ae. albopictus is comparable to the field strain, provided the larvae are fed optimally.     

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。     

Clones of Aedes albopictus cells resistant to methylmercaptopurine riboside

Four clones of A. albopictus cells resistant to 6-methylmercaptopurine riboside (MMPR) (MMPR-10, -11, -12, and -21) were isolated after mutagenesis of the parental LT C-7 cells. As assayed by plating efficiencies these clones were from ten- to 20-fold more resistant to MMPR than the LT C-7 cells. Resistance was also demonstrated by the fact that concentrations of MMPR, which reduced the levels of ATP and GTP in LT C-7 cells, had no such effect in the MMPR-resistant cells. When de novo purine biosynthesis was measured by the incorporation of [14C]formate into ATP and GTP, MMPR had little effect on the MMPR-10 cells (15% inhibition) but did depress synthesis considerably in the MMPR-11 cells (80% inhibition) although not as severely as in the LT C-7 cells (95% inhibition). Three of the resistant clones which were tested also showed considerable resistance to guanosine. Although the mechanism of resistance to MMPR in these cells is not clear it likely involves some alteration in one of the early enzymes involved in purine biosynthesis. Resistant as well as sensitive cells showed a new high-performance liquid chromatography peak after treatment with MMPR suggesting that there was no defect in the uptake of MMPR. The conversion of labeled adenosine to AMP, ADP, and ATP in the resistant cells indicated that these cells were not deficient in adenosine kinase, another possible mechanism of resistance to MMPR. All clones showed a reduction in GTP following treatment with ribavirin; however, they varied considerably with respect to the amount of ribavirin triphosphate which they formed. In the case of the MMPR-11 cells the amount of ribavirin triphosphate formed was markedly sensitive to cultural conditions. The fact that the various MMPR-resistant cells responded differently to ribavirin, and that quantitative differences were also seen in their responses to MMPR (as measured by [14C]formate incorporation) and to guanosine, suggests that there are significant phenotypic differences among these resistant clones.     

Biological cycle of Aedes albopictus (Diptera, Culicidae), in the laboratory]

Twelve colonies of Aedes albopictus were maintained at laboratory conditions, with the following results: Insectary conditions--Air humidity: 90-95%; Temperature: 25 degrees C; Blood source: human; Breeding places: Plastic glass or bamboo; Number eggs per female: 36.37; Incubation time: 1 to 6 days; Larval period: 4 to 9 days; Pupal period: 1 to 5 days; Adults life span: females--30.8 days and males--26.6 days.     

Effects of forced egg-retention in Aedes albopictus on adult survival and reproduction following application of DEET as an oviposition deterrent.

The insect repellent DEET (0.1% concentration), used as a mosquito oviposition deterrent in the laboratory, influenced the retention and maintenance of mature eggs by caged gravid female Aedes albopictus Skuse. This egg-retention mechanism could benefit survival because the gravid females were ultimately able to lay maintained eggs upon availability of water, but the length of forced egg-retention time reduced the number of eggs laid per female. Gravid females with retained eggs also laid a higher percentage of eggs that failed to tan, and this percentage increased with time duration of egg-retention. Percent egg hatch was not significantly affected by DEET when used as an oviposition deterrent; however, percent hatch was affected by time duration of egg-retention in both treated (exposed to DEET) and untreated (control) gravid females. The rate of egg hatch was considerably reduced after three weeks of retention; this reduction declined to zero for treated and control females at six and four weeks post-treatment, respectively. The fecundity and fertility of gravid female Ae. albopictus were affected by the time duration of forced egg-retention.     

Structure comparisons of Aedes albopictus densovirus with other parvoviruses

Parvoviridae is a family of the smallest viruses known with a wide variety of hosts. The capsid structure of the Aedes albopictus C6/36 cell densovirus (C6/36 DNV) at 1.2-nm resolution was obtained by elec-tron cryomicroscopy (cryoEM) and three-dimensional (3D) image reconstruction. Structure compari-sons between the C6/36 DNV and other parvoviruses reveal that the degree of structural similarity be-tween C6/36 DNV and the human parvovirus B19 is higher than that between C6/36 DNV and other in-sect parvoviruses. The amino acid sequence comparisons of structural and non-structural proteins also reveal higher levels of similarity between C6/36 DNV and parvovirus B19 than those between C6/36 DNV and other parvoviruses. These findings indicate that C6/36 DNV is closely related to the human virus B19, and the former might evolve from the human species other than from other insect viruses.     

Structure comparisons of Aedes albopictus densovirus with other parvoviruses

Parvoviridae is a family of the smallest viruses known with a wide variety of hosts. The capsid structure of the Aedes albopictus C6/36 cell densovirus (C6/36 DNV) at 1.2-nm resolution was obtained by electron cryomicroscopy (cryoEM) and three-dimensional (3D) image reconstruction. Structure comparisons between the C6/36 DNV and other parvoviruses reveal that the degree of structural similarity between C6/36 DNV and the human parvovirus B19 is higher than that between C6/36 DNV and other insect parvoviruses. The amino acid sequence comparisons of structural and non-structural proteins also reveal higher levels of similarity between C6/36 DNV and parvovirus B19 than those between C6/36 DNV and other parvoviruses. These findings indicate that C6/36 DNV is closely related to the human virus B19, and the former might evolve from the human species other than from other insect viruses.     

Susceptibility of Florida Aedes aegypti and Aedes albopictus to dengue viruses from Puerto Rico

Locally acquired dengue cases in the continental U.S. are rare. However, outbreaks of dengue‐1 during 2009, 2010, and 2013 in Florida and dengue‐1 and −2 in Texas suggest vulnerability to transmission. Travel and commerce between Puerto Rico and the U.S. mainland is common, which may pose a risk for traveler‐imported dengue cases. Mosquitoes were collected in Florida and used to evaluate their susceptibility to dengue viruses (DENV) from Puerto Rico. Aedes aegypti and Ae. albopictus were susceptible to virus infection with DENV‐1 and −2. No significant differences were observed in rates of midgut infection or dissemination between Ae. aegypti or Ae. albopictus for DENV‐1 (6–14%). Aedes aegypti was significantly more susceptible to midgut infection with DENV‐2 than Ae. albopictus (Ae. aegypti, ∼28%; Ae. albopictus, ∼9%). The dissemination rate with dengue‐2 virus for Ae. aegypti (23%) was greater than Ae. albopictus (0%), suggesting that Ae. albopictus is not likely to be an important transmitter of the DENV‐2 isolate from Puerto Rico. These results are discussed in light of Florida's vulnerability to DENV transmission.     

Differential Susceptibilities of Aedes aegypti and Aedes albopictus from the Americas to Zika Virus

BackgroundSince the major outbreak in 2007 in the Yap Island, Zika virus (ZIKV) causing dengue-like syndromes has affected multiple islands of the South Pacific region. In May 2015, the virus was detected in Brazil and then spread through South and Central America. In December 2015, ZIKV was detected in French Guiana and Martinique. The aim of the study was to evaluate the vector competence of the mosquito spp. Aedes aegypti and Aedes albopictus from the Caribbean (Martinique, Guadeloupe), North America (southern United States), South America (Brazil, French Guiana) for the currently circulating Asian genotype of ZIKV isolated from a patient in April 2014 in New Caledonia.Conclusions/SignificanceThis study suggests that although susceptible to infection, Ae. aegypti and Ae. albopictus were unexpectedly low competent vectors for ZIKV. This may suggest that other factors such as the large naïve population for ZIKV and the high densities of human-biting mosquitoes contribute to the rapid spread of ZIKV during the current outbreak.     

Repellent efficacy and safety evaluation of IR3535 derivative against Aedes albopictus,Culex pipiens pallens and Aedes togoi

The IR3535 derivative (LJH158), in which the ethyl ester of IR3535 was converted to methyl ester, was synthesized and studied as a new mosquito repellent. The repellent efficacy of LJH158 was compared with that of DEET against Aedes albopictus, Culex pipiens pallens and Aedes togoi. Also, the aromatic repellent tests were conducted with mixtures of repellents and the essential oils of cinnamon, which were obtained by supercritical fluid extraction. In addition, the safety issues of LJH158 were monitored using single oral dose safety methods and eye irritation, and skin irritation tests. The results of repellent efficacy in both biting and aromatic tests and safety tests demonstrate that LJH158 has high potential to be used as a new repellent or in combination with other repellents.     

Further data on the spread to Genoa of Aedes albopictus]

Further data are presented on the presence of Aedes albopictus in the town of Genoa (Italy) where this oriental mosquito was first reported in September 1990. Scattered foci of Ae albopictus were documented during the 1991 summer months in spite of a rather long and rigid '90-'91 winter season with temperatures frequently below 0 degree C. The newly imported mosquito shows the capacity to become a permanent pest in Italy where it could also increase the probability of transmission of pathogens such as arboviruses and filariae.     

Availability of insecticidal molecules to control Aedes albopictus (Skuse)

Following the implementation of the Directive 98/8/CE a few changes in the availability of insecticidal molecules to control Ae. albopictus have been outlined. Available products for larvicidal treatments will predominantly be based upon two growth regulators (diflubenzuron and pyriproxyfen). For the control of the adult forms there will mostly be active ingredients belonging to the pyrethroid group. Importance of surveillance for the onset of tolerance or resistance phenomena.     

The first report of Aedes (Stegomyia) albopictus in Haiti

Aedes albopictus was found in six of the 10 departments of Haiti and in 14 of the 35 communes surveyed. The survey found the larvae of Ae. albopictus in 13 different types of containers. Used tires and tins were by far the most common breeding sites used by this mosquito species. At the breeding sites, Ae. albopictus was associated with other mosquito species, such as Aedes aegypti, Culex nigripalpus and Aedes mediovittatus. The highest proportion of association was with Ae. aegypti. This study represents the first report of Ae. albopictus in Haiti.     

Laboratory and field evaluation of insect repellents as oviposition deterrents against the mosquito Aedes albopictus

Three experimental approaches were used to evaluate the oviposition deterrency of three insect repellents, AI3-35765, AI3-37220 (piperidine compounds), and the standard N,N-diethyl-3-methylbenzamide (deet) to the mosquito Aedes albopictus Skuse (Diptera: Culicidae). Against laboratory-reared Ae. albopictus gravid females, the EC50 values of AI3-37220, AI3-35765 and deet were 0.004%, 0.008% and 0.011% in laboratory cages and 0.004%, 0.01% and 0.009% in an outdoor screened cage. For a natural population of Ae. albopictus tested in the field, the EC50 values were determined as 0.004%, 0.008% and 0.001%, respectively. Ageing concentrations of 0.1% of each repellent provided >50% effective oviposition deterrency against the laboratory population of Ae. albopictus for 13 days in laboratory cages, for 15 days in the outdoor cage, and for 21 days against field population of Ae. albopictus in Florida. These topical skin repellents are effective oviposition deterrents for Ae. albopictus when employed at relatively low application rates.