Mosquito Control Methods Research Articles

Fight The Bite: Implementation of Mosquito-Based Curriculum in Elementary, Middle, and High Schools in Florida

Mosquitoes are both a nuisance and public health threat. In recent decades, outbreaks of dengue, chikungunya, and Zika in Florida have raised awareness of the importance of domestic and peri-domestic container mosquitoes, Aedes aegypti and Aedes albopictus. The synanthropic nature of these species, coupled with their preference for human bloodmeals, makes them a concern of and target for mosquito control. However, mosquito control programs (MCPs) often struggle to sustainably manage these mosquitoes because of the cryptic and abundant nature of their larval habitats, and negative public opinion towards MCPs and the use of insecticides. Fortunately, mosquito control can be improved by the actions of homeowners and residents as they have regular access to their own property and containers. School-based education programs can provide a means to community-wide education regarding mosquito control. We developed and delivered a mosquito education program to elementary, middle, and high school students. Knowledge of mosquitoes significantly improved in participating elementary and middle/ high school students. This knowledge was partially retained according to a follow-up test that was administered. Additionally, attitudes towards mosquito control and at-home control methods significantly improved following the instruction. The improvements in knowledge and attitudes observed in students suggest they can and should be targeted for mosquito education campaigns by mosquito control programs and educators.

Dengue Transmission Dynamics Analysis and Simulation in Minas Gerais - Brazil

Dengue control is a challenging task due to the complexity of the factors that involve its spread. The use of mathematical models to investigate the spread of dengue allows us to understand its behavior and provide information for its eradication. In this work, the analysis and simulation of the dynamics of dengue transmission to the State of Minas Gerais-Brazil- was proposed. Mathematical models were simulated using free software Scilab. In order to assess the impact on the epidemiological curve of the disease, the main methods of mosquito population control (insecticide, larvicide and mechanical control) were analyzed. The results obtained showed that mechanical control was the most efficient method, with 9.3% reduction of cases, as it acts directly in the breeding sites. It is noteworthy that insecticide and larvicide control also had a positive impact on the epidemiological curve, with a decrease of 7.9% and 6.3% of cases, respectively. This justifies the use of these techniques concurrently with mechanical control. The use of projections obtained by mathematical models can guide decision making regarding the adoption of public policies to reduce dengue cases.

California Residents' Perceptions of Gene Drive Systems to Control Mosquito-Borne Disease.

Scientists developing gene drive mosquitoes for vector control must understand how residents of affected areas regard both the problem of mosquito-borne disease and the potential solutions offered by gene drive. This study represents an experiment in public engagement at an early stage of technology development, intended to inform lab scientists about public attitudes toward their research and inspire consideration and conversation about the social ramifications of creating mosquitoes with gene drive. Online focus groups with California residents explored views on mosquito-borne disease risk, current mosquito control methods, and the proposed development and use of different classes of gene drives to control Ae. aegypti. Rather than a dogmatic rejection of genetic engineering or gene drive, many participants expressed pragmatic concerns with cost, control, the ability to narrowly target specific species, and the challenges of mistrust and institutional cooperation. Work like this can inform the alignment of community priorities and the professional priorities of scientists and vector control specialists.

Adult mosquito predation and potential impact on the sterile insect technique

The sterile insect technique is a promising environmentally friendly method for mosquito control. This technique involves releasing laboratory-produced sterile males into a target field site, and its effectiveness may be affected by the extent of adult mosquito predation. Sterile males undergo several treatments. Therefore, it is vital to understand which treatments are essential in minimizing risks to predation once released. The present study investigates the predation propensity of four mantis species (Phyllocrania paradoxa, Hymenopus coronatus, Blepharopsis mendica, Deroplatys desiccata) and two gecko species (Phelsuma standingi, P. laticauda) on adult Aedes aegypti, Ae. albopictus and Anopheles arabiensis mosquitoes in a laboratory setting. First, any inherent predation preferences regarding mosquito species and sex were evaluated. Subsequently, the effects of chilling, marking, and irradiation, on predation rates were assessed. The selected predators effectively preyed on all mosquito species regardless of the treatment. Predation propensity varied over days for the same individuals and between predator individuals. Overall, there was no impact of laboratory treatments of sterile males on the relative risk of predation by the test predators, unless purposely exposed to double the required sterilizing irradiation dose. Further investigations on standardized predation trials may lead to additional quality control tools for irradiated mosquitoes.

Quality Control Methods for Aedes albopictus Sterile Male Transportation.

Simple SummaryThe Sterile Insect Release Technique (SIT) is currently considered an environmentally friendly method to control populations of Aedes albopictus, an invasive mosquito species in Europe and elsewhere. Assessing the quality of mass reared, sterilized males that are transported to release sites is of the utmost importance for the success of the SIT programs. The current paper presents a series of quality control (QC) tests that have been conducted at the mass rearing facility in Italy and at delivery points in Greece and Montenegro to assess the impact of mass rearing, sterilization, and shipping on survival during transportation, longevity, flight ability and mating performance. Overall, our results reveal the detrimental effects of a long transportation period on the sterile male Ae. albopictus and provide a series of reliable QC tests to be considered in future SIT operations.Genetic based mosquito control methods have been gaining ground in recent years for their potential to achieve effective suppression or replacement of vector populations without hampering environments or causing any public health risk. These methods require the mass rearing of the target species in large facilities sized to produce millions of sterile males, as already well established for a number of insects of agricultural importance. Assessing the performance of released males in Sterile Insect Technique (SIT) control programs is of the utmost importance for the success of the operation. Besides the negative effects of mass rearing and sterilization, the handling of sterilized insects and shipment to distant areas may also negatively impact the quality of sterilized males. The aim of the current study was to design and executive quality control (QC) tests for sterilized Aedes albopictus (Asian tiger mosquito) males delivered by air shipment from the mass production facility located in Italy to Greece and Montenegro field release sites. Mass reared mosquito strains were based on biological materials received from Italy, Greece and Montenegro. Tests conducted at the mass rearing facility before transportation revealed a rather high residual female contamination following mechanical sex separation (approximately 1.5% females, regardless of the mosquito strain). Irradiated males of all three mosquito strains induced high levels of sterility to females. Shipment lasting approximately 24 h resulted in approximately 15% mortality, while when shipment lasted nearly two days this increased to almost 40%. The flight ability of sterilized males following one day transportation time was satisfactory (over 60%). The response of sterile males to food and water starvation was comparable and slightly lower than that of wild non-transported males. Longevity of sterile males was shorter than that of wild counterparts and it seems it was not affected by mating to wild females. Both mating propensity and mating competitiveness for wild virgin females was higher for the wild, control males compared to the sterile, transported ones. Overall, the performance of sterile male Ae. albopictus delivered from the mass rearing facility of Italy to Greece in approximately 24 h was satisfactory. Transportation lasting two days or longer incurred detrimental effects on males, which called into question the outcome of the SIT release programs. In conclusion, our results demonstrate the need of quality control procedures, especially when sterile male production facilities are not near to the releasing point. Transportation could be a serious drawback for the implementation of Sterile Insect Releases and, consequently, it is important to establish an efficient and fast transportation of sterilized males in advance.

Adult Anopheles Mosquito Distribution at a Low and High Malaria Transmission Site in Tanzania.

Malaria parasites are only transmitted by female mosquitoes of the genus Anopheles; hence, the disease's distribution is linked to that of the vector mosquitoes. As such, the goal of this study was to find out the spatial and temporal distribution of Anopheles mosquito adults in the research sites. This was a repeated cross-sectional ecological study that took place in Morogoro and Dodoma, Tanzania. Vacuum aspiration was used to collect mosquitoes both outside and inside human dwellings. All mosquito-related data was collected and entered into appropriate data collection forms. Female mosquitoes were recognized morphologically using Gillies and Coetzee morphological criteria, followed by PCR. In total, about 2742 Anopheles mosquitoes with an average collection of 18.21 ± 1.12 per day were collected outside human houses of which 1717 (10.51 ± 1.17) and 1025 (8.42 ± 1.41) were collected from Morogoro and Dodoma, respectively. Of the captured mosquitoes, 89.0%, 10.0%, and 1.0% were recognized as Anopheles arabiensis, Anopheles gambiae s.s., and Anopheles quadrianulatus, respectively. The distribution varied significantly with seasons, whereby 302 (4.72 ± 1.04) and 2440 (12.96 ± 1.52) mosquitoes were captured in the cold-dry and warm-wet season, respectively (p < 0.0001). Of the captured mosquitoes, 42.33%, 16.33%, 14.96%, and 4.27 were found on the ceiling, stored junks, verandas, and barks/tree, respectively. In malaria-endemic countries, vector control forms an important component of the malaria control efforts. This study found significant variation of Anopheles mosquito abundance in time and space with Anopheles arabiensis being the most predominant malaria vector. This signifies the need to introduce mosquito control methods that will target the less anthropophilic Anopheles arabiensis or the immature aquatic stages. The study further found that underbeds, store room/piled bags, and undisturbed curtains were the most preferred resting places by mosquitoes signifying to be the most effective strategic sites for spraying insecticides during the implementation of indoor residual spraying (IRS).

Spinosyns Delivered in Sugar Meals to Aedes aegypti and Aedes albopictus (Diptera: Culicidae): Acute Toxicity and Subacute Effects on Survival, Fecundity, and Fertility.

Sugar is an essential source of nutrition for adult mosquitoes to acquire energy. Toxic sugar bait (TSB) provides a promising method for mosquito control by incorporating toxins into artificial sources of sugar (i.e., toxic baits) presented to wild populations. Spinosyns comprise a family of bacterial secondary metabolites with a unique mode of action against the insect nervous system, an appealing environmental safety profile, and potential for incorporation into sugar baits. This research evaluated acute and subacute effects of spinosad (spinosyns A and D) and spinetoram (spinosyns J and L) in sugar meals on survival, fecundity, and fertility of Aedes aegypti and Aedes albopictus. Acute toxicity of spinosyns doubled from 24 to 48 h of assessment, revealing a relatively slow and cumulative action of the formulated spinosyns. Median lethal concentrations at 48 h were lower for spinetoram than for spinosad, lower for Ae. albopictus than Ae. aegypti, and lower for males than females. When exposed to subacute LC50 concentrations of spinosad and spinetoram for 24 h, survival of males and females of both species was diminished compared with controls, fecundity of females was increased, but fertility as measured by hatch rate of eggs was decreased. The formulations may have increased the nutritive value of the sugar meals thereby boosting fecundity, while toxifying embryos, reducing fertility. The inclusion of subacute effects of spinosyns allows assessment of the broader consequences of TSB for adult mosquito control.

Larvicidal Efficacy of Leaf Extracts of Rhanterium epapposum Oliv. Against Dengue Fever Mosquito Vector Larvae, Aedes aegypti L., (Diptera: Culicidae)

Dengue fever, transmitted by Aedes aegypti L. (Diptera: Culicidae), is the most important disease affecting human health and economy in the western part of Saudi Arabia. This study aimed to investigate the larvicidal activities of ethanolic, acetonic and aqueous extracts prepared from the leaves of Arfaj (Rhanterium epapposum Oliv.) against dengue fever mosquito vector, Aedes aegypti, under laboratory conditions. The larvicidal potency of ethanolic extract at high concentration of 50000 ppm was up to 98% after 24 h exposure. In contrast, acetonic and aqueous extracts caused 72 and 30% larval mortality, respectively, at the same concentration and exposure time. After 48 h exposure, the mortalities increased by 99, 86 and 35%, respectively, for ethanolic, acetonic and aqueous extracts. This study showed that the ethanolic extract had a higher larvicidal effect with lower LC50 value (168.15 ppm), followed by acetone (847.75 ppm) and aqueous (2278.22 ppm) extracts after 24 h exposure. Further studies are needed to isolate and identify the primary component responsible for larvicidal efficiency of this plant extract which may give good insights for developing a sustainable mosquito control method.

Effect of aqueous extract of lemon (Citrus limon) on Anopheles gambiae sensu lato (Diptera: Culicidae) larvae tolerance in malaria vector control in Dogbo district in south-western Republic of Benin, West Africa

The use of chemical insecticides causes important damages to environment and human health and there is a need to search for alternative solutions. This study aims to investigate on the effect of aqueous extract of lemon in Anopheles gambiae s.l. larvae tolerance in couffo department in south-western Republic of Benin, West Africa. Larvae of Anopheles gambiae s.l mosquitoes were collected from breeding sites using the dipping method in July 2020 during the rainy season in Dogbo district. A batch of 15 larvae of fourth instar were exposed to a mixture of aqueous extract of lemon with distilled water saturated with oxygen containing in each of five glass jars or test cups of same dimensions contained each 48 ml distilled water saturated with oxygen plus 2 ml of aqueous extract of lemon (Citrus limon) and one control jar containing no trace of aqueous extract of lemon. Larval mortality was recorded after 24hours, 48hours and 72hours exposure. The results show that the use of aqueous extract of lemon causes full-grown Anopheles larvae to die by suffocation. After the application of this mixture, the larvae of four instars cannot breathe. The use of aqueous extract of lemon is effective method for disturbing the siphonal respiration of mosquito larvae. Aqueous extract of lemon is effective method for mosquito larvae control.

Effect of coconut oil on Anopheles gambiae sensu lato (Diptera: Culicidae) larvae tolerance in malaria vector control in Dogbo district in south-western Benin, West Africa

The use of chemical insecticides causes important damages to environment and human health and there is a need to search for alternative solutions. This study aims to investigate on the effect of coconut oil on Anopheles gambiae sensu lato larvae tolerance in malaria vector control in Dogbo district in south-western Benin, West Africa. Larvae of Anopheles gambiae s.l. mosquitoes were collected from breeding sites using the dipping method in May 2020 during the rainy season in Dogbo district. A batch of 25 larvae of fourth instar were exposed to a mixture of coconut oil with distilled water saturated with oxygen containing in each of five glass jars or test cups of same dimensions contained each 48 ml distilled water saturated with oxygen plus 2 ml of coconut oil and one control jar containing no trace of coconut oil. Larval mortality was recorded after 24 hours, 48 hours and 72hours exposure. The results show that the use of coconut oil causes full-grown Anopheles larvae to die by suffocation. After the application of this mixture, the larvae of four instars cannot breathe. The use of coconut oil is effective method for disturbing the siphonal respiration of mosquito larvae. Coconut oil is effective method for mosquito larvae control.

Species Variety of the Calf and Human-Attracted Mosquitoes in Southwest Iran.

Background:Any mosquito control methods requires precise information about population dynamics, variety, biology and mosquito habitat. This research assessed Culicid mosquitoes’ attraction to a human host and a calf to better understand their behavior.Methods:Adult mosquitoes were sampled in 22 weeks in southwestern Iran’s Nur Ali Village from May to October 2015. The mosquitoes were drawn to the person and calf as bait, while the unbaited trap was also used. A substantial statistical difference between attracted mosquitoes to the hosts was determined in the T-test.Results:Within 22 weeks, 29821 mosquitoes were captured. Only 9% were collected from the human baited net trap, 89.1% from the calf baited net trap, and 1.9% from the unbaited net trap. The number of collected female mosquitoes was statistically significantly higher using the calf baited net trap of the total mosquitoes, 916 were randomly identified at the species level by local identification keys. Of these, 63 were Anopheles stephensi (human: 16%, calf: 75% and unbaited: 9%), 83 An. pulcherrimus (human: 27%, calf: 60% and unbaited: 13%), 118 Aedes caspius (human: 24%, calf: 69% and unbaited: 7%), 493 Culex tritaeniorhynchus (human: 52%, calf: 37% and unbaited: 11%), 153 Cx. quinquefasciatus (human: 44%, calf: 47% and unbaited: 9%), and 6 Cx. theileri (human: 33%, calf: 50% and unbaited: 17%).Conclusion:The obtained results here provide useful insights into the mosquito population and the possibility of using this information as an essential part of integrated vector management regarding the reemergence of malaria or other mosquito-borne.

Effect Of Thymus Vulgaris, Mentha Piperita And Pelargonium Citrosum Leaf, Syzygium Aromaticum Buds And Citrus Limonoids Peels Extracts As Mosquito Larvicidal And Pupicidal Agent

Mosquito control depends on application of synthetic insecticides. This has been limited due to its harmful effect on human health. This increased needs for botanical origin alternatives as a sustainable and more safe method of mosquito control. The current study aimed to evaluate larvicidal and pupicidal effect of thyme ( Thymus vulgaris ), peppermint ( Mentha piperita ) and citronella leaf ( Pelargonium citrosum ), clove buds ( Syzygium aromaticum ) and lemon peels ( Citrus limonoids) methanolic extracts. Tested plants were extracted and three concentrations of these extracts were prepared (25, 50 and 100 mg/ml) then their larvicidal and pupicidal activities were evaluated against 20 larvae and 20 pupas for each concentration. Mortality rate were calculated after 24 hrs. Adult mosquitoes were identified to genus level. Clove showed the highest larvae mortality rate (100%) for the three tested concentrations, followed by thyme, lemon and peppermint. Citronella had no effect as larvicidal agent. On the other hand, pupicidal activity test of thyme showed the highest results followed by clove. While lemon didn’t show any activity. Mosquito was identified as Culex. The result showed that buds extract of S. aromaticum and leaf extracts of T. vulgaris and peels extract of C. limonoids could serve as potential larvicidal extracts against the Culex mosquito.

Household-level risk factors for Aedes aegypti pupal density in Guayaquil, Ecuador

BackgroundVector-borne diseases are a major cause of disease burden in Guayaquil, Ecuador, especially arboviruses spread by Aedes aegypti mosquitoes. Understanding which household characteristics and risk factors lead to higher Ae. aegypti densities and consequent disease risk can help inform and optimize vector control programs.MethodsCross-sectional entomological surveys were conducted in Guayaquil between 2013 and 2016, covering household demographics, municipal services, potential breeding containers, presence of Ae. aegypti larvae and pupae, and history of using mosquito control methods. A zero-truncated negative binomial regression model was fitted to data for estimating the household pupal index. An additional model assessed the factors of the most productive breeding sites across all of the households.ResultsOf surveyed households, 610 satisfied inclusion criteria. The final household-level model found that collection of large solid items (e.g., furniture and tires) and rainfall the week of and 2 weeks before collection were negatively correlated with average pupae per container, while bed canopy use, unemployment, container water volume, and the interaction between large solid collection and rainfall 2 weeks before the sampling event were positively correlated. Selection of these variables across other top candidate models with ∆AICc < 1 was robust, with the strongest effects from large solid collection and bed canopy use. The final container-level model explaining the characteristics of breeding sites found that contaminated water is positively correlated with Ae. aegypti pupae counts while breeding sites composed of car parts, furniture, sewerage parts, vases, were all negatively correlated.ConclusionsHaving access to municipal services like bulky item pickup was effective at reducing mosquito proliferation in households. Association of bed canopy use with higher mosquito densities is unexpected, and may be a consequence of large local mosquito populations or due to limited use or effectiveness of other vector control methods. The impact of rainfall on mosquito density is multifaceted, as it may both create new habitat and “wash out” existing habitat. Providing services and social/technical interventions focused on monitoring and eliminating productive breeding sites is important for reducing aquatic-stage mosquito densities in households at risk for Ae. aegypti-transmitted diseases.Graphical

Field efficacy of ethnomedicinal plant smoke repellency against Anopheles arabiensis and Aedes aegypti

The repellency effect of smoke from burning Azadirachta indica, Eucalyptus camaldulensis and Ocimum forskolin plants to reduce human-mosquito biting activity. Ground mixed powders of the plant leaves produced smoke by direct burning and thermal expulsion on the traditional stoves in experimental huts against An. arabiensis and Ae. aegypti. A four-by-four Latin-square design was used to assign treatment and control experimental huts over different nights. In the treatment huts, the percent repellency of the smoke produced by burning powdered plant mixtures of the plants were determined by reduction mosquito density. There was a reduction on An. arabiensis (93.75%, P < 0.001) and Ae. aegypti (92%, P < 0.001) respectively, for huts with burning powder versus no treatment. Overall, plant mixed powders tested by both methods of application offered significant protection (>90%) against both mosquito species tested and has the potential to be used as an alternative mosquito control method.

Toxicity of plant extracts containing trypsin inhibitor to the larvae of Aedes aegypti

Mosquitoes are vectors of many pathogens and can transmit a range of potentially fatal diseases. Some of these diseases spread via mosquitoes belonging to the genus Aedes include Dengue, Chikungunya, Yellow fever, Zika etc. Conventional methods of mosquito control are not always completely successful. Therefore new strategies need to be adopted for mosquito control. Plant protease inhibitors are promising candidates as they prevent larval growth by inhibiting gut proteases of mosquito larvae. In this study we screened 15 plant extracts containing trypsin inhibitors for their toxicity to the larvae of Aedes aegypti. Leaf extracts from Lawsonia inermis showed the highest mortality with 100% mortality after 48 hours in second, third and in fourth instar larvae. The treatment with extract from Annona muricata leaf led to 100, 96 and 66% mortality after 48 hours in second, third and fourth instar larvae respectively. After Proteinase K treatment of Lawsonia inermis leaf extract, a reduction in the in vitro inhibition of larval gut protease activity from 82 to 6% and a decrease in mortality from 80 to 50% were observed compared to untreated. This revealed that the mortality, at least in part, is due to the presence of a protenaceous plant protease inhibitor in the extract. Expressing the gene coding for such protease inhibitors in micro organisms or algae upon which the mosquito larvae feeds will serve as an alternate method for control of mosquito population.

Exposure to mosquito coil and biomass fuel smoke and respiratory health in rural Tamil Nadu, India.

Mosquito coil smoke, along with biomass fuel smoke, are sources of indoor air pollution. Biomass fuel smoke has been studied as a risk factor for poor respiratory outcomes. However, in an Indian context, few studies examine the effect of mosquito coil exposure on poor respiratory outcomes at the community level. To estimate the prevalence of the biomass fuel and mosquito coil use and to determine the association between the use of bio-mass fuel and mosquito coil and poor respiratory health. A cross-sectional survey of 4662 individuals (above the age of 30years) was conducted using a pre-tested questionnaire. Trained interviewers collected data on current and past use of biomass fuels and mosquito coils, usage practices and respiratory health. We computed proportions for exposure variables namely biomass fuel, mosquito coil use and other covariates. We conducted univariate analysis, followed by multivariate logistic regression. The prevalence of ever use of biomass fuels was high (wood: 97.9%; cow dung cake: 76.0% and crop residue: 54.4%). Current use of wood, cow dung cake and crop residue was prevalent among 75.7, 24.3 and 30.9% respondents, respectively. Almost 70% of respondents had ever used mosquito coils, whereas 54% were current users. Overall, 5.5% respondents had poor respiratory health either due to chronic bronchitis or asthma. In multivariate analysis, use of combination of all three biomass fuel types (adjusted odds ratio [AOR] 1.69, 95% confidence interval [CI]: 1.13-2.54) and use of mosquito coil more than or equal to 5days per week (AOR 1.43, 95% CI: 1.04-1.99) were associated with poor respiratory health after adjusting for covariates age, gender, smoking, kitchen type and for each other. Use of biomass fuels and mosquito coils was high in the study population and was associated with poor respiratory health. Therefore, mosquito coil smoke should also be considered an important source of indoor air pollution, similar to biomass fuel exposure. Community education about these sources of indoor air pollution and increased coverage of cleaner fuels and alternative mosquito control methods should be the way forward in the rural areas.

An evaluation of repellency and feeding inhibition of ethno-medicinal plants against\xa0major malaria vectors in southern Ethiopia

BackgroundPlant-based mosquito control methods may use as a supplementary malaria vector control strategy. This study aimed to evaluate the effect of smoking ethno-medicinal plants on indoor density and feeding activity of malaria vectors at early hours of the night and its residual effect after midnight in southern Ethiopia.MethodsBoth field and tent trials were conducted to evaluate the impact of smoking Juniperus procera leaves, Eucalyptus globulus seeds and Olea europaea leaves in Kolla Shara Village from July 2016 to February 2017. For the field trial, five grass-thatched traditional huts (three for ethno-medicinal plants and two as control [only charcoal smoking and non-charcoal smoking]) were used. Indoor host-seeking mosquitoes were collected by CDC light traps. A Latin square design was employed to minimize the bias due to the variation in house location and different sampling nights. For the tent experiment, 25 3–5-day-old starved wild female Anopheles mosquitoes reared from the larvae were released into the tents where a calf was tethered at the mid-point of each tent.ResultsA total of 614 Anopheles mosquitoes belonging to 5 species were collected from 5 huts, of which 93.4% was An. arabiensis; O. europaea, E. globulus and J. procera reduced the indoor density of An. arabiensis, with the mean percentage drop of 80%, 73% and 70%, respectively. In the tent trial, smoking of these plants had significant knockdown effects and inhibited feeding on the calves (F = 383.5, DF = 3, P < 0.01). The mean knockdown effect due to O. europaea was relatively high (17.7 ± 0.54; 95% CI 16.8–18.6), while it was only 0.9 ± 0.1 (95% CI 0.29–1.52) in the control tents. All the test plants used in the tent trial caused significantly inhibited feeding activity of An. arabiensis on the host (F = 383.5, DF = 3, P < 0.01). About 94.5%, 89.5% and 86% of mosquitoes were unfed because of the smoking effect of O. europaea, E. globulus and J. procera, respectively, whereas only 19.5% were unfed in the control tent.ConclusionsSmoking ethno-medicinal plant materials reduced indoor density of malaria vectors and inhibited feeding on calves inside the tents. Thus, plant-based mosquito control methods may play a vital role in reducing mosquito bites in the early hours of the night and thereby reduce residual malaria transmission.Graphical

CONTROL OF ADULT AND LARVAL AEDES ALBOPICTUS WITH ATTRACTIVE TOXIC SUGAR BAITS (ACTIVE INGREDIENT: CINNAMON-SESAME OIL) IN NORTHEASTERN FLORIDA

Because traditional methods of mosquito control using insecticides has produced resistance, new methods that are environmentally friendly, sustainable and cost effective have been sought. One method, attractive toxic sugar baits (ATSB), uses the biological requirements, ecology, and behavior of mosquitoes to attract and kill them. In this study, the efficacy of a new ATSB active ingredient, microencapsulated cinnamon oil-plus-sesame oil, was tested in the laboratory and field against Aedes albopictus (Skuse) and the effect on non-target organisms was evaluated. The average mortality among groups of 20 third instar larvae after exposure to microencapsulated cinnamon-sesame oil ATSB in the laboratory for 48 h was high. Mortality at 10% and 1% ATSB concentration was 95.8% and 90.0% respectively and began to drop off (to 65%) at 0.1%. After application of the ATSB in the field, on day 11 of the study, the adult Ae. albopictus populations at the experimental site dropped significantly compared to pre-treatment levels and to the untreated control population. The differences between the control and the treated sites remained significant until the end of the study period on day 28. If used in accordance with label instructions and applied on non-flowering green vegetation, the potential impact on non-target populations was negligible with the exception of non-biting midges (Chironomidae). The synergistic effect of the attracting and killing adult mosquitoes as well as wash-off into part of the breeding sites with larvicidal cinnamon oil-plus-sesame oil product likely explains the high mortality of this ATSB formulation.

Knowledge, attitudes and perception of communities on mosquitoes and its control practices in Lagos State, Nigeria.

Introductionevidence-based mosquito control strategy is important for efficient and effective delivery of mosquito control interventions. This is hinged on effective community participation and thorough understanding of the Knowledge Attitude and Practices (KAPs) to achieve desired result. Such community dynamics are often understudied. We designed this study to assess the perception of four local communities on aspects of mosquito behavior, prevention and control in Lagos State, Nigeria.Methodsa cross-sectional survey was carried out using pretested semi-structured questionnaires to assess socio-demographic factors and KAPs in Kosofe, Alimosho, Ibeju-Lekki and Badagry Local Government Areas of Lagos State, Nigeria. Data analysis was carried out using IBM SPSS version 23.Resultsa total of 746 questionnaires were analyzed. Socio-demographic profile of the sampled population reveals that majority of the study population (73.1%) was between 18 and 40 years which constitute 49% males and 51% females. The knowledge of mosquito as a disease vector was high among the respondents which correlates with their level of education (P<0.05). The use of insecticide aerosols and Insecticides Treated Nets (ITNs) are the main control measures employed for mosquito control by respondents. Cost, convenience of usage and awareness majorly influenced the type of control measures that respondents adopt. Reasons such as not being easy to setup, skin irritation and the filling of being caged are reasons why some individuals do not use ITNs. Indoors, 32.4% of the respondents indicate the use of dichlorvos (DDVP) for household control of mosquitoes.Conclusionthe knowledge of mosquito control is high among middle aged individuals in Lagos State. Insecticide aerosols and ITNs are two major mosquito control methods used with DDVP insecticides frequently used indoors. This can inform the design of appropriate control methods in Lagos State.

Dengue Seroprevalence and Seroconversion in Urban and Rural Populations in Northeastern Thailand and Southern Laos.

Dengue is the most rapidly spreading mosquito-borne viral disease in the world. The detection of clinical cases enables us to measure the incidence of dengue infection, whereas serological surveys give insights into the prevalence of infection. This study aimed to determine dengue seroprevalence and seroconversion rates in northeastern Thailand and southern Laos and to assess any association of mosquito control methods and socioeconomic factors with dengue virus (DENV) infection. Cross-sectional seroprevalence surveys were performed in May and November 2019 on the same individuals. Blood samples were collected from one adult and one child, when possible, in each of 720 randomly selected households from two urban and two rural sites in both northeastern Thailand and southern Laos. IgG antibodies against DENV were detected in serum using a commercial enzyme-linked immunosorbent assay (ELISA) kit. Overall, 1071 individuals participated in the study. The seroprevalence rate was high (91.5%) across all 8 study sites. Only age and province were associated with seroprevalence rates. There were 33 seroconversions during the period from May to November, of which seven reported fever. More than half of the seroconversions occurred in the rural areas and in Laos. Dengue seroconversion was significantly associated with young age (<15 years old), female gender, province, and duration of living in the current residence. No socioeconomic factors or mosquito control methods were found to be associated with seroprevalence or seroconversion. Notably, however, the province with most seroconversions had lower diurnal temperature ranges than elsewhere. In conclusion, our study has highlighted the homogeneity of dengue exposure across a wide range of settings and most notably those from rural and urban areas. Dengue can no longer be considered to be solely an urban disease nor necessarily one linked to poverty.