Dengue Vector Control Research Articles

Evaluation of Effectiveness of a Community-Based Intervention for Control of Dengue Virus Vector, Ouagadougou, Burkina Faso.

We evaluated the effectiveness of a community-based intervention for dengue vector control in Ouagadougou, the capital city of Burkina Faso. Households in the intervention (n = 287) and control (n = 289) neighborhoods were randomly sampled and the outcomes collected before the intervention (October 2015) and after the intervention (October 2016). The intervention reduced residents’ exposure to dengue vector bites (vector saliva biomarker difference −0.08 [95% CI −0.11 to −0.04]). The pupae index declined in the intervention neighborhood (from 162.14 to 99.03) and increased in the control neighborhood (from 218.72 to 255.67). Residents in the intervention neighborhood were less likely to associate dengue with malaria (risk ratio 0.70 [95% CI 0.58–0.84]) and had increased knowledge about dengue symptoms (risk ratio 1.44 [95% CI 1.22–1.69]). Our study showed that well-planned, evidence/community-based interventions that control exposure to dengue vectors are feasible and effective in urban settings in Africa that have limited resources.

Evaluating the Effectiveness of a Community-Based Adaptation Strategy for Dengue Vector Control in Burkina Faso

Dengue outbreaks have occurred in several sub-Saharan African countries since 2010 and are expected to increase in the context of climate change. The success of efforts for prevention and control o...

Habitat Aedes Pradewasa dan Indeks Entomologi di 11 Kabupaten/Kota Provinsi Sumatera Selatan

Dengue fever and dengue haemorrhagic fever still becomes public health problems in South Sumatera Province with all of its regencies/cities have infested with Aedes aegypti. This research aimed to determine Aedes entomological indices and its breeding habitats. The research located at 11 regencies/cities, where in every regencies/cities determined two clusters (village) based on incidence rate in the last three years. Survey of preadult mosquito was carried out inside and outside areas of 1181 houses using single larva method with modification. The survey found that the dengue vector indices for house index, breteau index, and container index were at range 22,6% - 60,6%, 26,4 – 154,1 and 8,0% - 36,2% respectively. The most dominant water holding containers found infested with pre-adults mosquito were cement tanks (33,4%), followed by buckets (18,2%) and drums (14,7%). Inside houses, larva or pupae found dominants in cement tanks (44,3%), buckets (19,5%) and drums (13,9%), while outside of the house were used containers (20,7%), followed by drums (16,7%), buckets (15,0%) and used tires (11,9%). Statistical analysis by chi-square test showed a significant relationship between infested of Aedes pre-adults with characteristic of containers (colours, volume, location found and containers). Larval survey by visiting houses should carry out routinely and integrated into dengue vector control program.

Resistensi Malathion dan Aktivitas Enzim Esterase pada Populasi Nyamuk Aedes aegypti di Kabupaten Pekalongan

Pekalongan regency, Central Java (Indonesia) is one of area which experienced with Dengue Hemorrhagic Fever (DHF) incidence since many years ago. The extensive use of insecticides for dengue vector control has been carried out for long period in Pekalongan Regency. This fact stimulate the need to study the resistence status and esterase enzyme avtivity of Aedes aegypti to Malathion. The research was conducted in April-November 2014. Insecticide susceptibility assays were performed on F1 generation of wild-caught adult female Ae. aegypti mosquitoes from Simbangkulon Village Buaran Sub district, Kedungwuni Barat Village Kedungwuni Sub dsitrict and Karangsari Village Karanganyar Sub district, with the diagnostic doses of malathion (0,8%). Esterase enzyme activity of these mosquitoes was tested biochemically to find out the mechanisms of resistance to Malathion. Mosquitoes mortality as a result of Malathion effect showed variation in range from 3.33 to 13.75% in all study sites. That result indicated that Ae.aegypti mosquitoes are resistant to Malathion in all study sites . Based on biochemical assays, there was an increase if esterase enztyme activity of Ae aegypti in all study sites.. Therefore, alpha esterase enzyme activity could be associated with the mechanisms which responsible to malathion resistance in Ae. aegypti in Pekalongan. The results of this study provided the information about the malathion resistance status of Ae. aegypti in Pekalongan, and biochemical mechanisms which essential for monitoring the insecticide resistance in this area.

Comprehensive evaluation of demographic, socio-economic and other associated risk factors affecting the occurrence of dengue incidence among Colombo and Kandy Districts of Sri Lanka: a cross-sectional study

BackgroundComprehensive understanding of risk factors related to socio-economic and demographic status and knowledge, attitudes and practices (KAP) of local communities play a key role in the design and implementation of community-based vector management programmes, along with the identification of gaps in existing control activities.MethodsA total of 10 Medical Officers of Health (MOH) areas recording high dengue incidence over the last five years were selected from Colombo (n = 5) and Kandy (n = 5) Districts, Sri Lanka. From each MOH area, 200 houses reporting past dengue incidence were selected randomly as test group (n = 1000 for each district) based on the dengue case records available at relevant MOH offices. Information on socio-economic and demographic status and knowledge, attitudes and practices were gathered using an interviewer administered questionnaire. The control group contained 200 households from each MOH area that had not reported any dengue case and the same questionnaire was used for the assessment (n = 1000 for each district). Statistical comparisons between the test and control groups were carried out using the Chi-square test of independence, cluster analysis, analysis of similarities (ANOSIM) and multi-dimensional scaling (MDS) analysis.ResultsSignificant differences among the test and control groups in terms of basic demographic and socio-economic factors, living standards, knowledge, attitude and practices, were recognized (P < 0.05 at 95% level of confidence). The test group indicated similar risk factors, while the control group also shared more or less similar characteristics as depicted by the findings of cluster analysis and ANOSIM. Findings of the present study highlight the importance of further improvement in community education, motivation and communication gaps, proper coordination and integration of control programmes with relevant entities. Key infrastructural risk factors such as urbanization and waste collection, should be further improved, while vector controlling entities should focus more on the actual conditions represented by the public on knowledge, attitudes and personal protective practices.ConclusionsThe design of flexible and community friendly intervention programmes to ensure the efficacy and sustainability of controlling dengue vectors through community based integrated vector management strategies, is recommended.

Pengetahuan, Sikap dan Riwayat Pengendalian Vektor di Daerah Endemis Demam BerdarahDengue Kota Bandung

Dengue vector control needs active participation of community so it must be supported with goods dengue knowladge. The purpose of this research is to know the difference of knowladge and attitute in Bandung city community toward effort of dengue vector control in case and control group. This case-control study used ratio 1: 2. Number case of dengue is 261 and number of control is 522. Research location are ini health center area with hight dengue case ie Dago, Sekejati, Kopo, Cipamokolan. Responden ages grouped in range of 40-60 years, while the last education respondents are greduated from junior and senior high school. The result shows that there is significant different of knowladge between case and control (p-value 0.015) and no significant different in attitude variable (p-value 0,520). Vector control efford is different between two group in active eradication of mosquitoe breeding place (p-value 0.005) and the used of mosquito net (0.008). The odd ratio test result showed that knowladge variable (OR 1,410) and eradication of mosquitoe breeding place (OR1.719) are related to vector control efforts. Still needs enhance health promotion regarding vector control efforts in house hold environment as well as understanding of dengue, and optimizing program “one house one larva’s monitor

A “solution-focused” comparative risk assessment of conventional and synthetic biology approaches to control mosquitoes carrying the dengue fever virus

Emerging technologies often pose various uncertain health risks that cause policymakers to hesitate to allow resultant products and processes to enter the market—but they also may offer large benefits, including the potential to greatly reduce some of the very risks currently most greatly affecting public health and the environment. Synthetic biology serves as one such emerging technology that, despite its potential benefits to various fields, gives policymakers pause until the human and environmental health risks posed by genetically engineered organisms are better characterized and assessed. Given various limitations of our current paradigm for making risk management decisions, some of which are caused by limitations of conventional methods of quantitative risk assessment (QRA), a modified approach to emerging technology characterization and assessment might be a needed step change. This paper demonstrates how one such approach—“solution-focused risk assessment” (Finkel, Hum Ecol Risk Assess 17(4):754–787, 2011)—can help evaluate synthetic biology products against conventional competitors. Specifically, this paper conducts a SFRA for Oxitec’s engineered Aedes aegypti mosquito, which serves as a synthetic biology option for dengue virus vector control.

Efficacy of larvicides for the control of dengue, Zika, and chikungunya vectors in an urban cemetery in southern Mexico.

Many countries in Latin America have recently experienced outbreaks of Zika and chikungunya fever, in additional to the usual burden imposed by dengue, all of which are transmitted by Aedes aegypti in this region. To identify potential larvicides, we determined the toxicity of eight modern insecticides to A. aegypti larvae from a colony that originated from field-collected insects in southern Mexico. The most toxic compounds were pyriproxyfen (which prevented adult emergence) and λ-cyhalothrin, followed by spinetoram, imidacloprid, thiamethoxam, and acetamiprid, with chlorantraniliprole and spiromesifen the least toxic products. Field trails performed in an urban cemetery during a chikungunya epidemic revealed that insecticide-treated ovitraps were completely protected from the presence of Aedes larvae and pupae for 6 and 7weeks in spinosad (Natular G30) and λ-cyhalothrin-treated traps in both seasons, respectively, compared to 5-6weeks for temephos granule-treated ovitraps, but was variable for pyriproxyfen-treated ovitraps with and 1 and 5weeks of absolute control in the dry and rainy seasons, respectively. Insecticide treatments influenced the mean numbers of Aedes larvae + pupae in each ovitrap, mean numbers of eggs laid, and percentage of egg hatch over time in both trials. The dominant species was A. aegypti in both seasons, although the invasive vector Aedes albopictus was more prevalent in the rainy season (26.7%) compared to the dry season (10.2%). We conclude that the granular formulation of spinosad (Natular G30) and a suspension concentrate formulation of λ-cyhalothrin proved highly effective against Aedes spp. in both the dry and rainy seasons in the cemetery habitat in this region.

Molecular evidence for new sympatric cryptic species of Aedes albopictus (Diptera: Culicidae) in China: A new threat from Aedes albopictus subgroup?

BackgroundAedes (Stegomyia) albopictus (Skuse) is an indigenous species and the predominant vector of dengue fever in China. Understanding of genetic diversity and structure of the mosquito would facilitate dengue prevention and vector control. Sympatric cryptic species have been identified in the Ae. albopictus subgroup in Southeast Asia; however, little is known about the presence and distribution of cryptic species in China. This study aimed to examine the genetic diversity, evaluate potential new cryptic sibling species, and assess the prevalence of Wolbachia infections in field populations.MethodsAedes adult female specimens were collected from five provinces in southern and central China during 2015–2016. Morphological identification was performed under dissection microscope. The mitochondrial DNA cytochrome c oxidase subunit 1 (cox1, DNA barcoding) locus and the ribosomal DNA internal transcribed spacer region 2 (ITS2) marker were used to examine the genetic variation, evaluate cryptic sibling species, and population structure in the field populations. Screening for the presence of Wolbachia was performed using multiplex PCR.ResultsA total of 140 individual specimens with morphological characteristics similar to Ae. albopictus were sequenced for DNA barcoding. Among these, 129 specimens (92.1%) were confirmed and identified as Ae. albopictus. The remaining 11 specimens, from 2 provinces, were identified as 2 distinct sequence groups, which were confirmed by ITS2 marker sequencing, suggesting the existence of potential cryptic species of Ae. albopictus. In Ae. albopictus, we found significant genetic differentiation and population structure between populations collected from different climate zones. Medium to high frequencies of Wolbachia infections were observed in natural Ae. albopictus populations, whereas Wolbachia was infrequent or absent in cryptic species populations.ConclusionsOur findings highlight the population differentiation by climate zone and the presence of novel, cryptic Aedes species in China. The low prevalence of Wolbachia infections in cryptic species populations could reflect either a recent invasion of Wolbachia in Ae. albopictus or different host immune responses to this symbiont in the cryptic species. The study provides useful information for vector control and host-symbiont coevolution. Further study is needed to investigate the potential for arbovirus infection and disease transmission in the emerged cryptic species.

Social Marketing on Dengue Hemorrhagic Fever and Tuberculosis Prevention and Control Program in Pati, Central Java, Indonesia

Indonesia has the highest number of dengue fever cases in Southeast Asia and the second highest TB cases in the world. Both diseases are related to behavior. Social marketing focuses on changes in health behaviors. This study aimed to apply social marketing on dengue mosquito vector control and TB case finding and to analyze the effect of social marketing training on the knowledge and skills of community health workers (CHWs). A mixed method design was conducted in Pati, Central Java, Indonesia. First, a case study was conducted using field observation, in-depth interviews, focus group discussions (FGD), and document review. In-depth interviews and FGD were conducted on 55 participants including 40 community leaders and 15 CHWs. Data were analyzed using content analysis. Second, intervention study was conducted on social marketing training of 30 CHWs. The independent variable was social marketing training. The dependent variables were knowledge and skill of dengue mosquito vector control and TB case finding. The effect of training was analyzed by paired t test. The results showed that knowledge (p&lt;0.001) and skill (p&lt;0.001) in dengue mosquito vector control and TB case finding increased significantly after training. Qualitative assessment showed that CHWs were more able to identify health problems in the community and to perform TB case finding and dengue mosquito breeding place eradication. After training they also became more knowledgeable in applying social marketing approach to address the health problem. In conclusion, social marketing strategy can be used to address community health problem.

Resistance of Aedes aegypti (Diptera: Culicidae) Populations to Deltamethrin, Permethrin, and Temephos in Cambodia.

Dengue fever is a major public health concern, including 185,000 annual cases in Cambodia. Aedes aegypti is the primary vector for dengue transmission and is targeted with insecticide treatments. This study characterized the insecticide resistance status of Ae aegypti from rural and urban locations. The susceptibility to temephos, permethrin, and deltamethrin of Ae aegypti was evaluated in accordance with World Health Organization instructions. All the field populations showed lower mortality rate to temephos compared with the sensitive strain with resistance ratio 50 (RR50) varying from 3.3 to 33.78 and RR90 from 4.2 to 47 compared with the sensitive strain, demonstrating a generalized resistance of larvae to the temephos in Cambodia. Ae aegypti adult populations were highly resistant to permethrin regardless of province or rural/urban classification with an average mortality of 0.02%. Seven of the 8 field populations showed resistance to deltamethrin. These results are alarming for dengue vector control, as widespread resistance may compromise the entomological impact of larval control operations. Innovative vector control tools are needed to replace ineffective pesticides in Cambodia.

Assessing dengue transmission risk and a vector control intervention using entomological and immunological indices in Thailand: study protocol for a cluster-randomized controlled trial

BackgroundDengue fever is the most common and widespread mosquito-borne arboviral disease in the world. There is a compelling need for cost-effective approaches and practical tools that can reliably measure real-time dengue transmission dynamics that enable more accurate and useful predictions of incidence and outbreaks. Sensitive surveillance tools do not exist today, and only a small handful of new control strategies are available. Vector control remains at the forefront for combating dengue transmission. However, the effectiveness of many current vector control interventions is fraught with inherent weaknesses. No single vector control method is effective enough to control both vector populations and disease transmission. Evaluations of novel larval and adult control interventions are needed.Methods/designA cluster-randomized controlled trial will be carried out between 2017 and 2019 in urban community clusters in Khon Kaen and Roi Et cities, northeastern Thailand. The effectiveness of a pyriproxyfen/spinosad combination treatment of permanent water storage containers will be evaluated on epidemiological and entomological outcomes, including dengue incidence, number of female adult dengue vectors infected or not infected with dengue virus (DENV), human exposure to Aedes mosquito bites, and several other indices. These indices will also be used to develop predictive models for dengue transmission and impending outbreaks. Epidemiological and entomological data will be collected continuously for 2 years, with the intervention implemented after 1 year.DiscussionThe aims of the trial are to simultaneously evaluate the efficacy of an innovative dengue vector control intervention and developing predictive dengue models. Assessment of human exposure to mosquito bites by detecting antibodies generated against Aedes saliva proteins in human blood samples has, so far, not been applied in dengue epidemiological risk assessment and disease surveillance methodologies. Likewise, DENV detection in mosquitoes (adult and immature stages) has not been used in any practical way for routine disease surveillance strategies. The integration of multiple outcome measures will assist health authorities to better predict outbreaks for planning and applying focal and timely interventions. The trial outcomes will not only be important for Thailand, but also for the entire Southeast Asian region and further afield.Trial registrationISRCTN, ISRCTN73606171. Registered on 23 June 2017.

Dengue fatality prediction using data mining

Dengue fever, a mosquito-borne tropical disease caused by the dengue virus is life-threatening. In Malaysia, although necessary control measures have been carried out, the number of dengue fever cases keeps increasing. Among the measures, dengue vector control appears to be the most effective way to control the spread of the dengue virus particularly in Malaysia. The aim of this research is to study the current implementation of dengue outbreak control in Malaysia and predict dengue fever cases using data mining techniques. Real data on dengue fever and weather are collected from the Ministry of Health in its Perak Tengah district office and Perak Meteorological office respectively. Different data mining classification techniques are applied onto these data with the performance of each technique is measured. The results highlight the best performance among techniques used.

Molecular Detection and Characterization of Wolbachia pipientis from Culex quinquefasciatus Collected from Lahore, Pakistan.

The gram-negative, pleomorphic endosymbiont Wolbachia is known to infect a large number of insects and other arthropods naturally. This bacterium modifies the host biology, mainly causing reproductive alterations including feminization, death of male, parthenogenesis, and importantly cytoplasmic incompatibility. Wolbachia-induced cytoplasmic incompatibility results in nonviable offspring and vector population suppression. In addition, this bacterium rapidly spreads and propagates within the host population. This study is the first report on Wolbachia detection and characterization from Culex quinquefasciatus collected from Lahore, Pakistan. For this purpose, mosquito adults were collected from different localities of Lahore and identified at the species level. A total of 145 pairs of ovaries were individually subjected to DNA isolation, and polymerase chain reaction amplification of three (wsp, 16S rRNA, and ftsZ) genes were investigated. In all, 128 females were found positive, representing 82.3% infection rate. The phylogenetic analysis indicated that the detected endosymbiont had 100% homology with Wolbachia pipientis wPip strain and supergroup B. The detection of the local strain of Wolbachia (wPip) will be useful in investigating its potential for the control of dengue vector (Aedes aegypti) and reducing dengue transmission in Pakistan.

Effectiveness of a novel long-lasting pyriproxyfen larvicide (SumiLarv\xae2MR) against Aedes mosquitoes in schools in Yangon, Myanmar

BackgroundMosquito-borne diseases are prevalent in Myanmar, with the number of dengue cases showing a significant increase in recent years. Dengue vectors have developed resistance to insecticides and currently used larvicides show only short-term effectiveness. As a result, an alternative larvicide is urgently needed. The present study evaluated the larvicidal effectiveness of long-lasting pyriproxyfen resin discs (SumiLarv®2MR) against dengue virus vectors in schools in Hlaing Thar Yar Township, Yangon.ResultsThe proportion of Aedes mosquito-infested containers was significantly reduced in the schools applied with the larvicide (OR: 0.24, 95% CI: 0.12–0.48) while there was little reduction noted in the control schools (OR: 0.97, 95% CI: 0.55–1.72). The density of infested containers was also significantly reduced in the intervention schools (Beta: -1.50, 95% CI: -1.98– -1.04), but there was no significant reduction in density in the control schools (Beta: -0.19, 95% CI: -0.53–0.14). The proportion of adult emergence was less than 20% in the treated water collected from the intervention schools for six months, while the proportion was over 90% in the untreated water. In addition, eight-month-old SumiLarv®2MR resin discs were still 100% effective when tested in the laboratory. More than 50% of the discs disappeared from treated containers within two months of intervention.ConclusionsSumiLarv®2MR was effective in reducing Aedes-infested containers at least six months after its application in schools. This new pyriproxyfen formulation has great potential for improving the current dengue vector control program in Myanmar.

Building the evidence base for dengue vector control: searching for certainty in an uncertain world

Building the evidence base for dengue vector control: searching for certainty in an uncertain world

PRELIMINARY PHYTOCHEMICAL QUALITATIVE AND QUANTITATIVE ANALYSIS OF BRASSICA OLERACEA LEAF EXTRACTS ON FOURTH INSTAR LARVAE OF AEDES AEGYPTI (CULICIDEA: DIPTERA)

Aedes aegypti, dengue fever mosquito, is primarily associated with the transmission of dengue in tropical and subtropical regions of the world. The present investigations was carried out to assess the larvicidal efficacy of aqueous and ethanol leaf extract of Brassica oleracea var. botrytis L against 4th instar larvae of Ae.aegypti. The concentration of extracts prepared from the leaf of plant Brassica oleracea var.botrytis L. were screened for their larvicidal activity against early fourth instars of dengue vector. The mortality rate of Ae.aegypti against aqueous and ethanol extracts of B.oleracea as follows 72% and 96%. Ethanol extract exposed to IVth larvae of Ae.aegypti is more efficiency than the aqueous extract. The present investigation suggest the possible use B. oleracea L. as an agent for the control of dengue vector, A. aegypti.

High Levels of Resistance in A Culex quinquefasciatus Population to the Insecticide Permethrin in Filariasis Endemic Areas in Central Java

Resistance among Culex mosquitoes to various insecticides has been reported in many countries. However, there have been no studies of the resistance status of Culex in Indonesia. There is a need for such studies to develop a database for use in vector control management. This study aimed to investigate the insecticide resistance status of C. quenquefasciatus , which is the primary vector of filariasis, to aid the planning of a vector control management program. In the present study, Culex quinquefasciatus larvae were collected from five districts/municipalities where filariasis is endemic in Central Java. The larvae were reared to adult stage, and insecticide susceptibility testing was then conducted according to standard bioassay procedures of the World Health Organization (WHO). The results of the bioassays showed that C. quinquefasciatus had a high level of resistance against 0.75% permethrin, with mortality rates ranging from 4.8 to 21.6%. The lowest resistance was found among mosquitoes collected from Grobogan district. This may be explained by the district’s remote geographical location. The high level of resistance found in the present study may be caused by exposure to local insecticides, which have been applied for many years as part of a dengue vector control program. These insecticides may also have contaminated the breeding sites of C. quinquefasciatus mosquitoes. Better vector control management is needed to help prevent the development and spread of resistance. Such management should include routine insecticide surveillance and insecticide alternation.

Green synthesis of silver nanoparticles using Holarrhena antidysenterica (L.) Wall.bark extract and their larvicidal activity against dengue and filariasis vectors.

The present study was carried out to evaluate the larvicidal potential of methanol, hexane, acetone, chloroform, and aqueous bark extracts of Holarrhena antidysenterica (L.) Wall. and silver nanoparticles (AgNPs) synthesized using aqueous bark extract against the third instar larvae of Aedes aegypti L. and Culex quinquefasciatus Say. AgNPs were prepared by adding 10ml of aqueous bark extract in 90ml of 1mM silver nitrate (AgNO3) solution. After 5min of mixing, a change in color from yellow to dark brown occurred indicating the synthesis of AgNPs. Their further characterization was done through ultraviolet-visible spectroscopy (UV-Vis), X-ray diffraction analysis (XRD), field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR). UV-Vis spectrum of synthesized AgNPs showed a maximum absorption peak at 420nm wavelength. Crystalline nature of AgNPs was confirmed by the presence of characteristic Bragg reflection peaks in XRD pattern. TEM images have shown that most of the AgNPs were spherical in shape with an average size of 32nm. FT-IR spectrum of AgNPs showed prominent absorbance peaks at 1012.2 (C-O) and 3439.44cm-1 (O-H) which represent the major constituents of phenolics, terpenoids, and flavonoids compounds. LC-MS analysis of the bark extract confirmed the presence of carbonyl and hydroxyl functional groups which were directly correlated with FT-IR results. These AgNPs were assayed against different mosquito vectors, and the maximum mortality was recorded against the larvae of A. aegypti with LC50 and LC90 values being 5.53 and 12.01ppm, respectively. For C. quinquefasciatus, LC50 and LC90 values were 9.3 and 19.24ppm, respectively, after 72h of exposure. Bark extracts prepared in different solvents such as methanol, chloroform, hexane, acetone, and water showed moderate larvicidal activity against A. aegypti their respective LC50 values being 71.74, 94.25, 102.25, 618.82, and 353.65ppm and LC90 values being 217.36, 222.24, 277.82, 1056.36, and 609.37ppm. For C. quinquefasciatus, their LC50 values were 69.43, 112.39, 73.73, 597.74, and 334.75ppm and LC90 values of 170.58, 299.76, 227.48, 1576.98, and 861.45ppm, respectively, after 72h of treatment. AgNPs proved to be nontoxic against the non-target aquatic organism, Mesocyclops thermocyclopoides Harada when exposed for 24, 48, and 72h. The results showed that bark extract-derived AgNPs have extremely high larvicidal potential compared to other organic solvents as well as aqueous bark extract alone. These AgNPs, therefore, can be used safely for the control of dengue and filarial vectors that cause severe human health hazards.

Evaluation of sticky traps for adult Aedes mosquitoes in Malaysia: a potential monitoring and surveillance tool for the efficacy of control strategies.

The present study compared the performance of sticky traps in order to identify the most effective and practical trap for capturing Aedes aegypti and Aedes albopictus mosquitoes. Three phases were conducted in the study, with Phase 1 evaluating the five prototypes (Models A, B, C, D, and E) of sticky trap release-and-recapture using two groups of mosquito release numbers (five and 50) that were released in each replicate. Similarly, Phase 2 compared the performance between Model E and the classical ovitrap that had been modified (sticky ovitrap), using five and 50 mosquito release numbers. Further assessment of both traps was carried out in Phase 3, in which both traps were installed in nine sampling grids. Results from Phase 1 showed that Model E was the trap that recaptured higher numbers of mosquitoes when compared to Models A, B, C, and D. Further assessment between Model E and the modified sticky ovitrap (known as Model F) found that Model F outperformed Model E in both Phases 2 and 3. Thus, Model F was selected as the most effective and practical sticky trap, which could serve as an alternative tool for monitoring and controlling dengue vectors in Malaysia.