Toxicity and bioaccumulation of fipronil in the nontarget arthropodan fauna associated with subalpine mosquito breeding sites

In order to examine ecological impact of fipronil use for larval culicine control in natural hydrosystems, toxicity and bioaccumulation of this new insecticide were analyzed on aquatic species representative of the nontarget arthropodan fauna (nonculicine larval Diptera: Chaoboridae, Chironomidae; planktonic Crustacea: Cladocera, Copepoda, Ostracoda) associated with target larval mosquito populations in the subalpine breeding sites. Standard toxicological bioassays using fipronil aqueous solutions from 1 to 2000 nM indicated different sensitivity levels among species. Insecticide bioaccumulation analyses, using [(14)C]fipronil solutions in simplified laboratory ecosystem, also indicated large differences among species. These differences may come from biological parameters characteristic of each species. Taking into account these nontarget effects of fipronil, a possible strategy of use of this insecticide for integrated mosquito control management was proposed, which is based upon selective dietary absorption of the insecticide by larval Culicidae.     

Characterization of mosquito breeding sites in and in the vicinity of tigray microdams

Background

Malaria vector control in Ethiopia has a history of more than 50 years, but malaria remains a major cause of morbidity and mortality in Ethiopia. Thus, targeting the control program on the larval stage is of paramount importance. This study aimed to characterize the aquatic habitats of vector mosquito larvae associated with micro-dams.

Methods

Cross-sectional larval survey was conducted on six micro-dams in Tigray, Northern Ethiopia in 2005/06. The study area on each dam was divided into eight zones. Immature stages of mosquitoes were collected using standard dippers. The physico-chemical characteristics of the aquatic habitats were measured onsite.

Results

A total of 301 aquatic habitats were surveyed for mosquito larvae; in 32.56% (n=301) only Anopheles, in 27.91% only Culex, both genera were found mixed in 21.59% and no mosquito larvae were found in 17.94%. The findings depicted that dissolved oxygen (r = 0.34, p =0.04), pH (r = 0.35, p =0.03), conductivity (r = 0.36, p =0.03), vegetation (F = 3.54, p =0.002), microhabitat (F = 2.65, p =0.04), fauna and bottom surface of the water body were positively associated and important in explaining the presence and abundance of Culex. On the other hand, dissolved oxygen (r = 0.39, p =0.02), pH (r = 0.42, p =0.008), vegetation (F = 5.6, p =0.000), water transparency (F = 2.72, p =0.00), rainfall (F = 2.22, p = 0.027) and fauna were positively associated and important in explaining the presence and abundance of Anopheles.

Conclusion

The findings of this study suggest that both biotic (vegetation and fauna) and abiotic (chemical and physical) factors play a significant role in larvae''s habitat preference in both Culex and Anopheles.     

上海浦东机场蚊幼孳生地的调查

目的调查了解上海浦东机场地区蚊幼种类分布和习性。方法捞勺和水网法。结果野外采集的蚊幼在室温条件下饲养羽化成虫4 174只,共4属11种(按蚊属1种,库蚊属8种,伊蚊属1种,阿蚊属1种);致倦库蚊、淡色库蚊和迷走库蚊幼虫主要孳生在洼地积水、水坑与电桩积水,三带喙库蚊、中华按蚊、二带喙库蚊、凶小库蚊、红胸库蚊和褐尾库蚊孳生在芦苇沟与水沟,白纹伊蚊孳生于小型容器积水,骚扰阿蚊孳生于粪池。结论浦东机场蚊幼孳生地较为广泛,应加强环境的综合治理。     

Toxicity of vegetable tannins on crustacea associated with alpine mosquito breeding sites

The impact of tannins from the environmental vegetation naturally polluting Alpine mosquito breeding sites was experimentally investigated by studying the toxicity of tannic acid, a natural hydrolyzable tannin, on the nontarget crustacean fauna associated with culicine populations. Bioassays indicate that exposure to tannic acid at concentrations from 0.06 to 2.0 mM is more deleterious to Chydorus sphaericus, Diaptomus castor, and Eucypris fuscata, than to Daphnia pulex, Acanthocyclops robustus, and Eucypris virens. Histopathological investigations after treatment with tannic acid at concentrations from 0.125 to 0.500 mM reveal sequential degenerative patterns of the midgut epithelium depending on the taxon, duration of the treatment, and concentrations assayed. These differential toxic effects on Crustacea are compared with those previously observed in larval Diptera, in order to evaluate the plant tannins as potentially useful products in integrated mosquito management programs.     

“V”形槽河（沟）底在消除蚊、鼠、螺孳生地时的作用

云南省大理州的云龙和南涧县城内均有河流穿城而过，穿过云龙县城的狮尾河因泥沙淤积，曾于1993年引发城区洪涝灾害。为此云龙县治理了县城内的狮尾河；南涧县为满足县城发展扩建的需要，对流经县城的南涧河县城段也进行了改造治理。两县建造“V”形槽河（沟）底的主观愿望是预防洪涝灾害的发生，建成后除实现主观愿望外，客观上还起到消除蚊、鼠等孳生地的作用，从而降低蚊媒及鼠传疾病的风险，现报告如下。     

Larvicidal activities of some organotin compounds on mosquito larvae: a QSAR study

Mosquitoes are not only the cause of nuisance by their bites but also transmit deadly diseases like malaria, filariasis, yellow fever, dengue, and Japanese encephalitis. In this paper, nine QSAR models were developed using different series of organotins with respect to their larvicidal activities against Aedes aegypti and Anopheles stephensi mosquito larvae. Internal [cross-validation (LOO-q(2)), quality factor (Q), Fischer statistics (F), and Y-randomization] and external validation tests have validated all these QSAR models. QSAR results suggest that the two most important determinants for the toxicity are the hydrophobic (pi) and Hammett electronic (sigma(+)) parameters of the substituents, and the kill mechanism is different for these two species of mosquito larvae. On the basis of QSAR (6), nine compounds 4a-4i are suggested as potential synthetic targets.     

福州市内河蚊虫孳生情况的调查

目的了解福州市内河的蚊虫孳生情况,为城市科学灭蚊提供依据。方法采用目测和勺捕相结合的方法,调查福州市城区和城乡接合部内河蚊虫孳生的情况,以500 ml勺捕捞幼虫,计算孳生严重的内河的蚊幼密度(条/勺);选取孳生严重的内河进行蚊虫孳生的季节消长调查。结果调查城区河道300处,孳生2处,孳生频率为0.67%,调查城乡接合部河道200处,孳生24处,孳生率为12.0%。主要孳生蚊种为致倦库蚊,伴有少量褐尾库蚊孳生,幼虫密度最高可达到657条/勺。幼虫主要孳生在内河两岸和水生植物周围。福州市内河蚊虫孳生有比较明显的季节变化,5和11月为密度的2个高峰,2和8月为密度的2个低谷。结论福州城市内河在一定条件下会成为超大型蚊虫孳生地,是城市灭蚊中不可忽视的孳生场所。     

室外环境积水引起蚊幼孳生的状况调查

[目的 ]　探讨环境积水的数量、分布 ,以及蚊幼的孳生规律和白纹伊蚊传播登革热的危险程度。　 [方法 ]　根据孳生地调查方法 ,在居民和单位的外部寻找所有环境积水 ,检查蚊幼孳生情况。 [结果 ]共有 2 87个积水孳生蚊幼 ,孳生率为 14 .68% ,其中农村与城镇无显著性差异 ( χ2 =3 .743 ,P >0 .0 5 )。单位高于居民 ( χ2 =16.64 9,P <0 .0 5 )。以牧场、停业企业、公园蚊幼孳生率最高 ;容器以柏油桶、晒水容器、肥料水缸、地面积水的阳性率最高 ;水质以半污水孳生率最高。孳生密度以污水最高。　 [结论 ]　室外环境积水不但影响环境卫生 ,而且孳生大量蚊虫 ,易引起疾病流行 ,7～ 9月白纹伊蚊幼虫密度指数已达到WHO值三级 ,已足以引起登革热的发生和流行。     

Simple intervention to reduce mosquito breeding in waste stabilisation ponds

Waste stabilisation ponds (WSP) are the preferred method for treatment of urban wastewater in low-income countries but, especially in arid regions, the pond systems can be important breeding sites for mosquitoes of medical importance. In a WSP system in Faisalabad, Pakistan, we assessed the impact of simple environmental interventions on mosquito occurrence and abundance. Reducing the amount of floating matter in the ponds, eliminating emergent vegetation and repairing cracks in the cement structure reduced the number of mosquito-positive samples in the intervention ponds to almost zero, whereas the control ponds had a significant number of positive samples. This suggests that a combination of simple low-cost interventions is a feasible environmental management strategy for vector control in WSP systems that are located in areas where medically important mosquitoes may breed in the shallow ponds.     

鲁西南稻田区蚊虫种类及幼虫孳生情况调查

目的 调查鲁西南稻田区媒介蚊虫种类和蚊幼虫孳生情况,为稻田蚊虫的防治提供依据.方法 利用勺捕法调查蚊幼虫密度,成蚊调查采用人帐诱蚊法、CO2诱蚊灯诱捕法以及帐扣法.结果 鲁西南稻田区共捕获蚊虫6属11种,其中幼虫9种,成蚊11种,优势蚊种为三带喙库蚊、淡色库蚊和中华按蚊,分别占捕获成蚊总数的45.79％、29.32％和22.74％.在整个水稻生长季节,稻田均有幼虫孳生,稻田库蚊和按蚊幼虫密度分别在7月中下旬和8月中下旬出现两个高峰,库蚊高峰期幼虫密度最高为1.88条/勺,最低密度为0.08条/勺;按蚊高峰期幼虫密度最高达2.82条/勺,最低密度为0.09条/勺.结论 稻田区蚊虫孳生地种类多样化,蚊虫种类丰富,应以成蚊防治为主,稻田幼虫可采用田间间歇灌溉的方法控制密度.     

Species diversity of mosquito breeding in rubber plantations of Kerala, India

During south-west monsoon season, rubber plantations in Kerala have been found to provide ideal conditions for the proliferation of mosquitoes. In a study conducted from June 2005 to September 2010 in Kannur, Wayanad, and Kozhikode districts, 12 species of mosquitoes in 6 genera--Aedes, Armigeres, Culex, Heizmannia, Toxorhynchites, and Verrallina--were found to breed in rain water-filled cups used for collecting rubber latex. The only vector species found was Aedes albopictus, known for its ability to transmit dengue and chikungunya. The combinations of species found associated in the latex cups is also presented.     

山西省蚊虫孳生调查及防控研究

目的调查山西省蚊虫孳生环境、孳生率及蚊虫种类,并以此分析蚊虫防控策略。方法以容器法检查人群活动场所中蚊幼阳性水体的种类、数量,并对蚊虫进行种类鉴定。结果阳泉蚊幼孳生率最高为63.6%,临汾次之,为60.0%,忻州、太原、吕梁、长治孳生率在15%～30%之间。蚊虫孳生生境以闲置容器最高,为55.5%,布放容器次之,为40.0%,废置轮胎、贮水容器等逐渐减低。此次调查共采集蚊种12种,分布最多的地区是长治,有11种,临汾较多,有9种。结论自然条件适合蚊虫的长治地区因大力进行环境卫生清洁工程而使蚊虫孳生率大大降低,阳泉、临汾等地因环境卫生整治力度差造成的小型积水使蚊虫孳生率大大增高。全民爱国卫生运动对于控制蚊虫孳生有非常重要的作用。     

<Emphasis Type="Italic">Aedes aegypti</Emphasis> breeding ecology in Guerrero: cross-sectional study of mosquito breeding sites from the baseline for the Camino Verde trial in Mexico

Background

Understanding the breeding patterns of Aedes aegypti in households and the factors associated with infestation are important for implementing vector control. The baseline survey of a cluster randomised controlled trial of community mobilisation for dengue prevention in Mexico and Nicaragua collected information about the containers that are the main breeding sites, identified possible actions to reduce breeding, and examined factors associated with household infestation. This paper describes findings from the Mexican arm of the baseline survey.

Methods

In 2010 field teams conducted household surveys and entomological inspections in 11,995 households from 90 representative communities in the three coastal regions of Guerrero State, Mexico. We characterized Ae. aegypti breeding sites and examined the effect of two preventive measures: temephos application in water containers, and keeping the containers covered. We examined associations with household infestation, using bivariate and multivariate analysis adjusted for clustering effects.

Results

We conducted entomological inspections in 11,995 households. Among 45,353 water containers examined, 6.5% (2958/45,353) were positive for larvae and/or pupae. Concrete tanks (pilas) and barrels (tambos) together accounted for 74% of pupal productivity. Both covering water containers and inserting temephos were independently associated with a lower risk of presence of larvae or pupae, with the effect of covering (OR 0.22; 95% CIca 0.15–0.27) stronger than that of temephos (OR 0.66; 95% CIca 0.53–0.84). Having more than four water containers was associated with household infestation in both rural areas (OR 1.42; 95% CIca 1.17–1.72) and urban areas (1.81; 1.47–2.25), as was low education of the household head (rural: 1.27; 1.11–1.46, and urban: 1.39; 1.17–1.66). Additional factors in rural areas were: household head without paid work (1.31; 1.08–1.59); being in the Acapulco region (1.91; 1.06–3.44); and using anti-mosquito products (1.27; 1.09–1.47). In urban areas only, presence of temephos was associated with a lower risk of household infestation (0.44; 0.32–0.60).

Conclusion

Concrete tanks and barrels accounted for the majority of pupal productivity. Covering water containers could be an effective means of Ae. aegypti vector control, with a bigger effect than using temephos. These findings were useful in planning and implementing the Camino Verde trial intervention in Mexico.

     

石家庄市蚊幼虫孳生情况调查

目的 调查石家庄市区蚊幼虫孳生情况,为蚊虫防制提供科学依据.方法 于2011年7-8月对小型积水和容器积水采用直接观察法,大中型水体采用目测法结合捞勺法调查孳生情况;同时采集阳性积水或水体中的蚊幼虫带回实验室鉴定.结果 大中型水体广场喷泉池、公园景观水域(人工湖)、民心河(环城人工河),平均阳性率为10.94％;各类小型积水和容器积水1120处,蚊幼虫孳生阳性221处,阳性率在6.35％～38.46％之间,平均阳性率为19.73％.蚊幼虫孳生优势种群为白纹伊蚊和淡色库蚊,其中白纹伊蚊占42.74％,淡色库蚊占35.55％.结论 石家庄市不同水体蚊虫孳生各具特点,为蚊虫防制和治理策略制定提供了依据.     

大连市城区蟑螂孳生场所及类型研究

目的了解和掌握大连市蟑螂孳生场所及类型。方法粘捕法。结果大连市城区德国小蠊为绝对优势种,占99.11%;不同场所中餐饮密度指数最高,其次为洗浴和农贸市场;不同生境中厨房的密度指数最高。结论德国小蠊为优势种群,餐饮、洗浴和农贸市场是蟑螂孳生和危害的重点行业,应当加强对这些行业单位蟑螂的监测与防治。     

Acid sulfate soils in intertidal mosquito breeding habitats and implications for habitat modification

Public concern about the use of chemicals for mosquito control in coastal Australia has lead to the development of physical habitat modification methods that aim to reduce mosquito populations to acceptable levels. Habitat modification methods include runnels (depth < 0.30 m) and ditches (depth > 0.50 m). During excavation for habitat modification, a risk of exposure of acid sulfate soils may exist. Acid sulfate soils are soils that contain iron sulfides, in particular pyrite (FeS2), and produce sulfuric acid when exposed to air. These soils occur predominantly in coastal lowland areas that are also prime mosquito breeding habitats. The paper discusses the problem and illustrates the application of survey methods that facilitate wise decision making and management of intertidal wetlands.     

武汉市综合治理垸内钉螺孳生地项目管理模式探讨

2004年春季至2006年春季,武汉市对全市垸内钉螺孳生地进行了全面综合治理,取得显著成效,达到了改造钉螺孳生环境、基本消灭垸内钉螺,减少人畜感染,控制血吸虫病流行的目的。对巩固和扩大该市已取得的血防成果,保障疫区广大人民群众的身体健康和生命安全,促进农村社会经济全面协调发展有着重大的意义。同时,项目建立了贯穿实施全过程的一整套行之有效的管理模式,可为同类地区开展防治工作,提供可借鉴的经验。     

Further extension of the range of the rock pool mosquito, Aedes atropalpus, via tire breeding

In the past, Aedes atropalpus was limited to those areas of the eastern U.S. and Canada that had rivers or shorelines with large rocks containing rock pools. In the last 10 years, many new records of larval breeding in scrap tires have accumulated. We present records of larval breeding in non-rock pool containers for 54 counties; most are far from the original range. The species has not only found a new habitat but has greatly extended its range via commercial transport of scrap tires.