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2.
Pestic Biochem Physiol ; 171: 104743, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33357565

RESUMEN

Cinnamodial (CDIAL) is a drimane sesquiterpene dialdehyde found in the bark of Malagasy medicinal plants (Cinnamosma species; family Canellaceae). We previously demonstrated that CDIAL was insecticidal, antifeedant, and repellent against Aedes aegypti mosquitoes. The goal of the present study was to generate insights into the insecticidal mode of action for CDIAL, which is presently unknown. We evaluated the effects of CDIAL on the contractility of the ventral diverticulum (crop) isolated from adult female Ae. aegypti. The crop is a food storage organ surrounded by visceral muscle that spontaneously contracts in vitro. We found that CDIAL completely inhibited spontaneous contractions of the crop as well as those stimulated by the agonist 5-hydroxytryptamine. Several derivatives of CDIAL with known insecticidal activity also inhibited crop contractions. Morphometric analyses of crops suggested that CDIAL induced a tetanic paralysis that was dependent on extracellular Ca2+ and inhibited by Gd3+, a non-specific blocker of plasma membrane Ca2+ channels. Screening of numerous pharmacological agents revealed that a Ca2+ ionophore (A23187) was the only compound other than CDIAL to completely inhibit crop contractions via a tetanic paralysis. Taken together, our results suggest that CDIAL induces a tetanic paralysis of the crop by elevating intracellular Ca2+ through the activation of plasma membrane Ca2+ channels, which may explain the insecticidal effects of CDIAL against mosquitoes. Our pharmacological screening experiments also revealed the presence of two regulatory pathways in mosquito crop contractility not previously described: an inhibitory glutamatergic pathway and a stimulatory octopaminergic pathway. The latter pathway was also completely inhibited by CDIAL.


Asunto(s)
Aedes , Repelentes de Insectos , Insecticidas , Animales , Benzaldehídos , Femenino , Insecticidas/farmacología , Control de Mosquitos
3.
Malar J ; 19(1): 411, 2020 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-33198747

RESUMEN

The global COVID-19 pandemic has been affecting the maintenance of various disease control programmes, including malaria. In some malaria-endemic countries, funding and personnel reallocations were executed from malaria control programmes to support COVID-19 response efforts, resulting mainly in interruptions of disease control activities and reduced capabilities of health system. While it is principal to drive national budget rearrangements during the pandemic, the long-standing malaria control programmes should not be left behind in order to sustain the achievements from the previous years. With different levels of intensity, many countries have been struggling to improve the health system resilience and to mitigate the unavoidable stagnation of malaria control programmes. Current opinion emphasized the impacts of budget reprioritization on malaria-related resources during COVID-19 pandemic in malaria endemic countries in Africa and Southeast Asia, and feasible attempts that can be taken to lessen these impacts.


Asunto(s)
Presupuestos/tendencias , Infecciones por Coronavirus/economía , Enfermedades Endémicas/economía , Recursos en Salud/economía , Malaria/economía , Pandemias/economía , Neumonía Viral/economía , África , Asia Sudoriental , Presupuestos/estadística & datos numéricos , Infecciones por Coronavirus/prevención & control , Enfermedades Endémicas/prevención & control , Recursos en Salud/tendencias , Humanos , Malaria/prevención & control , Control de Mosquitos/economía , Control de Mosquitos/tendencias , Pandemias/prevención & control , Neumonía Viral/prevención & control
4.
Malar J ; 19(1): 410, 2020 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-33198754

RESUMEN

BACKGROUND: In the past decade substantial reduction in malaria morbidity and mortality has been observed through well-implemented case management and vector control strategies. India has also achieved a significant reduction in malaria burden in 2018 and has committed to eliminate malaria by 2030. The Mandla Malaria Elimination Demonstration Project (MEDP) was started in 2017 in 1233 villages of District Mandla to demonstrate malaria elimination in a tribal district with hard-to-reach areas was possible using active and passive surveillance, case management, vector control, and targeted information, education and communication campaigns. An operational plan was developed to strengthen the existing surveillance and malaria elimination systems, through fortnightly active case detection to ensure that all cases including those that are introduced into the communities are rapidly identified and treated promptly. The plan also focused on the reduction of human-mosquito contact through the use of Long-Lasting Insecticial Nets (LLINs) and Indoor Residual Spray (IRS). The operational plan was modified in view of the present COVID-19 pandemic by creating systems of assistance for the local administration for COVID-related work while ensuring the operational integrity of malaria elimination efforts. RESULTS: The use of MEDP study design and operational plan, with its built-in management control systems, has yielded significant (91%) reduction of indigenous cases of malaria during the period from June 2017 to May 2020. The malaria positivity rate was 0.33% in 2017-18, 0.13% in 2018-19, and 0.06% in 2019-20. Mass screening revealed 0.18% malaria positivity in September-October 2018, followed by 0.06% in June 2019, and 0.03% in December 2019, and these were mostly asymptomatic cases in the community. The project has been able to sustain the gains of the past three years during the ongoing COVID-19 pandemic. CONCLUSION: This paper provides the study design and the operational plan for malaria elimination in a high-burden district of Central India, which presented difficulties of hard to reach areas, forest malaria, and complex epidemiology of urban and rural malaria. The lessons learned could be used for malaria elimination efforts in rest of the country and other parts of South Asia with comparable demography and epidemiology.


Asunto(s)
Infecciones por Coronavirus/prevención & control , Prestación de Atención de Salud/métodos , Enfermedades Endémicas/prevención & control , Malaria/prevención & control , Pandemias/prevención & control , Neumonía Viral/prevención & control , Vigilancia de la Población/métodos , Altitud , Animales , Infecciones por Coronavirus/epidemiología , Prestación de Atención de Salud/organización & administración , Enfermedades Endémicas/estadística & datos numéricos , Bosques , Instituciones de Salud/estadística & datos numéricos , Personal de Salud/estadística & datos numéricos , Humanos , India/epidemiología , Mosquiteros Tratados con Insecticida , Malaria/epidemiología , Control de Mosquitos , Neumonía Viral/epidemiología , Prevalencia , Lluvia , Población Rural , Población Urbana
5.
Mem Inst Oswaldo Cruz ; 115: e200271, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33146241

RESUMEN

BACKGROUND: Aedes aegypti is the primary transmitter of several arbovirus with great impact in human health. Controlling vector mosquitoes is an essential and complex task. One promising control method is to use mosquitoes as a vehicle to disseminate tiny particles of juvenile-killing insecticides, such as pyriproxyfen (PPF), to breeding sites. OBJECTIVES: We aimed to investigate the capacity of Ae. aegypti to disseminate two new formulations of PPF in two sites of Rio de Janeiro city for assessment of the efficacy of these products. METHODS: Dissemination stations impregnated with powder and liquid new formulations of PPF were installed in two test sites. Ovitraps were used in the test sites and in a control site for monitoring the presence of Ae. aegypti throughout eggs collection. FINDINGS: Entomological indices indicated that the new formulations of PPF were efficient in reducing eggs abundance. Liquid formulation performed better than powder formulation. Ready-to-use formulations of PPF can be quickly applied in the field and can be replaced after a few months. MAIN CONCLUSIONS: New formulations of PPF associated with mosquito dissemination approach make a valuable vector control strategy, managing to cover places of difficult access for whatever reason. New formulations application requires less labour, being economically attractive.


Asunto(s)
Aedes/efectos de los fármacos , Insecticidas/farmacología , Larva/efectos de los fármacos , Control de Mosquitos/métodos , Piridinas/farmacología , Adolescente , Animales , Ciudades , Humanos , Larva/crecimiento & desarrollo , Mosquitos Vectores/efectos de los fármacos , Mosquitos Vectores/crecimiento & desarrollo
6.
Korean J Parasitol ; 58(5): 543-550, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-33202506

RESUMEN

Mosquitoes are globally distributed and important vectors for the transmission of many human diseases. Mosquito control is a difficult task and the cost of preventing mosquito-borne diseases is much lower than that for curing the associated diseases. Thus, chemical control remains the most effective tool for mosquito. Due to the long-term intensive use of insecticides to control mosquito vectors, resistance to most chemical insecticides has been reported. This study aimed to investigate the relationship between insecticide resistance and target site mutation of L1014 kdr and G119 ace alleles in 5 species/species group of mosquitoes (Aedes vexans, Ae. albopictus, Anopheles spp., Culex pipiens complex, and Cx. tritaeniorhynchus) obtained from 6 collection sites. For Anopheles spp., the proportion of mosquitoes with mutated alleles in L1014 was 88.4%, homozygous resistant genotypes were observed in 46.7%, and heterozygous resistant genotypes were observed in 41.8%. For the Cx. pipiens complex and Cx. tritaeniorhynchus species, homozygous resistant genotypes were found in 25.9% and 9.8%, respectively. However, target site mutation of L1014 in the Ae. vexans nipponii and Ae. albopictus species was not observed. Anopheles spp., Cx. pipiens complex, and Cx. tritaeniorhynchus mosquitoes were resistant to deltamethrin and chlorpyriphos, whereas Ae. vexans nipponii and Ae. albopictus were clearly susceptible. We also found a correlation between the resistance phenotype and the presence of the L1014 kdr and G119 ace mutations only in the Anopheles spp. population. In this study, we suggest that insecticide resistance poses a growing threat and resistance management must be integrated into all mosquito control programs.


Asunto(s)
Alelos , Proteínas de Insectos/genética , Resistencia a los Insecticidas/genética , Insecticidas/farmacología , Control de Mosquitos , Mosquitos Vectores/efectos de los fármacos , Mosquitos Vectores/genética , Mutación/efectos de los fármacos , Animales , Monitoreo del Ambiente , Humanos , Mosquitos Vectores/clasificación , República de Corea , Enfermedades Transmitidas por Vectores/prevención & control , Enfermedades Transmitidas por Vectores/transmisión
7.
Trends Parasitol ; 36(11): 877-880, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-33036938

RESUMEN

Adequate sexual competitiveness of sterile males is a prerequisite for genetic control methods, including the sterile insect technique. During the past decade several semi-field and open-field trials demonstrated that irradiated male mosquitoes can be competitive.


Asunto(s)
Culicidae/fisiología , Infertilidad Masculina , Control de Mosquitos/métodos , Conducta Sexual Animal/efectos de la radiación , Animales , Culicidae/efectos de la radiación , Masculino , Radiación Ionizante
8.
PLoS One ; 15(10): e0239728, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33048941

RESUMEN

INTRODUCTION: School-aged children become a highly vulnerable group for malaria, yet they are less likely to use malaria prevention interventions. Previous studies exploring perception on cause of malaria mainly focused on pregnant mothers or parents of children under age five years. Exploring parent's perception on cause of malaria and their experiences on the prevention of malaria and associated challenges among school-aged children is important to develop a malaria prevention education package for school-aged children to reduce malaria and malaria related morbidities among school-aged children. METHODS: A descriptive qualitative study is conducted in Kutcha district by recruiting 19 parents of school-aged children for semi-structured interviews, 6 key informants and 6 focus group discussion which consists of parents, health development army and health extension workers. A semi-structured interview guide is used to guide the interview process. The collected data is analyzed thematically with a focus on the three major areas of concern: perceived cause of malaria, experience of malaria prevention and challenges of bed net use for prevention of malaria. RESULTS: Five causes of malaria were identified, namely hunger, mosquito bite, exposure to hot sunshine, poor sanitation and hygiene and eating some sweet foods and unripe maize. Participants perceived that eating sweet foods and unripe maize lead to enlargement of the spleen that ends in malaria while poor hygiene and sanitation leads to either development of the ova of mosquito and the landing of the housefly to contaminate food for consumption. The experiences of malaria prevention were largely influenced by their perceived cause of malaria. The malaria prevention measures undertaken by parents were vectors control measures, homemade herbal remedies and restricting children from eating sweet foods. The challenges of malaria prevention by using bed nets were related to a negative attitude, sleeping behaviors of children; use of bed nets for unintended purposes, shortage of bed nets and delays in the distribution of bed nets. CONCLUSION: There were misconceptions about the cause of malaria and associated experiences of malaria prevention. Control of malaria among school-aged children need health education targeting the challenges and correcting identified misconceptions by parents in Kutcha district and in other similar settings.


Asunto(s)
Conocimientos, Actitudes y Práctica en Salud/etnología , Malaria/prevención & control , Padres/psicología , Adulto , Etiopía/epidemiología , Femenino , Grupos Focales , Educación en Salud , Humanos , Mordeduras y Picaduras de Insectos , Mosquiteros Tratados con Insecticida , Malaria/etiología , Masculino , Control de Mosquitos/métodos , Padres/educación , Investigación Cualitativa
9.
PLoS Negl Trop Dis ; 14(9): e0008365, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32898130

RESUMEN

Insecticide resistance poses a significant threat to the control of arthropods that transmit disease agents. Nanoparticle carriers offer exciting opportunities to expand the armamentarium of insecticides available for public health and other pests. Most chemical insecticides are delivered by contact or feeding, and from there must penetrate various biological membranes to reach target organs and kill the pest organism. Nanoparticles have been shown to improve bioactive compound navigation of such barriers in vertebrates, but have not been well-explored in arthropods. In this study, we explored the potential of polyanhydride micro- and nanoparticles (250 nm- 3 µm), labeled with rhodamine B to associate with and/or transit across insect biological barriers, including the cuticle, epithelium, midgut and ovaries, in female Ae. aeygpti mosquitoes. Mosquitoes were exposed using conditions to mimic surface contact with a residual spray or paint, topical exposure to mimic contact with aerosolized insecticide, or per os in a sugar meal. In surface contact experiments, microparticles were sometimes observed in association with the exterior of the insect cuticle. Nanoparticles were more uniformly distributed across exterior tissues and present at higher concentrations. Furthermore, by surface contact, topical exposure, or per os, particles were detected in internal organs. In every experiment, amphiphilic polyanhydride nanoparticles associated with internal tissues to a higher degree than hydrophobic nanoparticles. In vitro, nanoparticles associated with Aedes aegypti Aag2 cells within two hours of exposure, and particles were evident in the cytoplasm. Further studies demonstrated that particle uptake is dependent on caveolae-mediated endocytosis. The propensity of these nanoparticles to cross biological barriers including the cuticle, to localize in target tissue sites of interest, and to reach the cytoplasm of cells, provides great promise for targeted delivery of insecticidal candidates that cannot otherwise reach these cellular and subcellular locations.


Asunto(s)
Aedes/fisiología , Nanopartículas , Polianhídridos , Aedes/citología , Animales , Línea Celular , Endocitosis , Femenino , Control de Mosquitos/métodos , Rodaminas/química , Distribución Tisular
10.
PLoS One ; 15(9): e0238323, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32898853

RESUMEN

India, a persistently significant contributor to the global malaria burden, rolled out several anti-malaria interventions at the national and state level to control and recently, to eliminate the disease. Odisha, the eastern Indian state with the highest malaria burden experienced substantial gains shown by various anti-malaria initiatives implemented under the National Vector-borne Disease Control Programme (NVBDCP). However, recalcitrant high-transmission "pockets" of malaria persist in hard-to-reach stretches of the state, characterised by limited access to routine malaria surveillance and the forested hilly topography favouring unbridled vector breeding. The prevalence of asymptomatic malaria in such pockets serves as perpetual malaria reservoir, thus hindering its elimination. Therefore, a project with the acronym DAMaN was initiated since 2017 by state NVBDCP, targeting locally identified high endemic 'pockets' in 23 districts. DAMaN comprised biennial mass screening and treatment, provisioning of long-lasting insecticidal net (LLIN) and behavioural change communication. Subsequently, to inform policy, assessment of DAMaN was conceived that aims to estimate the coverage of the various components of the project; the prevalence of malaria, even at sub-patent level especially among pregnant/lactating women and children; and its impact on malaria incidence. A survey of DAMaN beneficiaries will measure coverage; and knowledge and practices related to LLIN; along with collection of blood specimens from a probability sample. A multi-stage stratified clustered sample of 2228 households (~33% having pregnant/lactating women) will be selected from 6 DAMaN districts. Routine DAMaN project data (2017-2018) and NVBDCP data (2013-2018) will be extracted. Rapid Diagnostic Test, Polymerase Chain Reaction and blood smear microscopy will be conducted to detect malarial parasitemia. In addition to measuring DAMaN's coverage and malarial prevalence in DAMaN pockets, its impact will be estimated using pre-post differences and Interrupted Time Series analysis using 2017 as the "inflection" point. The assessment may help to validate the unique strategies employed by DAMaN.


Asunto(s)
Antimaláricos/uso terapéutico , Mosquiteros Tratados con Insecticida/estadística & datos numéricos , Malaria/epidemiología , Malaria/prevención & control , Control de Mosquitos/organización & administración , Control de Mosquitos/normas , Plasmodium malariae/efectos de los fármacos , Adolescente , Niño , Preescolar , Femenino , Gobierno , Humanos , Incidencia , India/epidemiología , Lactante , Análisis de Series de Tiempo Interrumpido , Malaria/parasitología , Malaria/transmisión , Embarazo , Encuestas y Cuestionarios
11.
Exp Parasitol ; 218: 107988, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32890471

RESUMEN

In the present work, we synthesized silver nanoparticles supported by rice husk by hydrothermal treatment, as-synthesized silver nanoparticles rice husk (AgNPs-RH) bio-composite mixed with potter clay thoroughly, molded, dried into a disc-shaped before firing and applying as a point of use larvicidal agent. As designed, porous terracotta disc (PTD) infused with AgNPs-RH-biocomposite were characterized by UV spectrophotometer, Fourier-transform infrared spectroscopy, transmission electron microscopy, X-ray diffraction analysis and energy-dispersive X-ray spectroscopy. The amount of silver ions released from the PTD was also found to be within the prescribed limit of 0.1 ppm-level. Later we dropped the PTD and tested its larvicidal activity against the IVth instar larva stage of Aedes, Anopheles and Culex species. We found 100% larvicidal mortality in 24 h of exposure to the designed PTD and the amount of silver released from the porous disc was found to be 0.0343 ppm. Further from the histopathological studies of dead larvae revealed that the silver ions from the PTD have substantially damaged the exoskeleton of larvae.


Asunto(s)
Aedes , Anopheles , Culex , Nanopartículas del Metal/normas , Control de Mosquitos/instrumentación , Animales , Ecosistema , Tecnología Química Verde , Larva , Nanopartículas del Metal/economía , Nanopartículas del Metal/provisión & distribución , Microscopía Electrónica de Transmisión , Control de Mosquitos/economía , Oryza , Plata , Espectrometría por Rayos X , Espectrofotometría Atómica , Espectrofotometría Ultravioleta , Espectroscopía Infrarroja por Transformada de Fourier , Difracción de Rayos X
12.
PLoS Negl Trop Dis ; 14(9): e0008716, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32966283

RESUMEN

The concurrent circulation of dengue and coronavirus disease 2019 (COVID-19) may produce many unfavourable outcomes-such as co-infections; delays in diagnosis, treatment, and mitigation measures; overwhelming of the healthcare system; underreporting of cases; deterioration in surveillance and control interventions; and exacerbation of social inequalities. Indeed, lockdown is greatly compromising the effectiveness of vector control, especially social mobilization campaigns and preventive insecticide spraying in private spaces (indoor and peridomestic spraying). Thus, failure to appropriately implement the full range of vector control interventions can lead to a reduction in their overall effectiveness and an increasing risk of vector-borne diseases circulating. Consequently, the health community and policy makers should develop proactive policies and allocate adequate resources to prevent and manage the resurgence of dengue and other vector-borne diseases in the new era of COVID-19.


Asunto(s)
Infecciones por Coronavirus/epidemiología , Dengue/epidemiología , Dengue/prevención & control , Control de Mosquitos/métodos , Neumonía Viral/epidemiología , Prevención Primaria/métodos , Betacoronavirus , Prestación de Atención de Salud , Humanos , Pandemias , Control de Plagas/métodos , Salud Pública , Tiempo de Tratamiento
13.
PLoS Negl Trop Dis ; 14(9): e0008705, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32986704

RESUMEN

Over the past three decades, Europe has witnessed an increased spread of invasive aedine mosquito species, most notably Aedes albopictus, a key vector of chikungunya, dengue and Zika virus. While its distribution in southern Europe is well documented, its dispersal modes across the Alps remain poorly investigated, preventing a projection of future scenarios beyond its current range in order to target mosquito control. To monitor the presence and frequency of invasive Aedes mosquitoes across and beyond the Alps we set oviposition and BG-Sentinel traps at potential points of entry with a focus on motorway service areas across Switzerland. We placed the traps from June to September and controlled them for the presence of mosquitoes every other week between 2013 and 2018. Over the six years of surveillance we identified three invasive Aedes species, including Ae. albopictus, Ae. japonicus and Ae. koreicus. Based on the frequency and distribution patterns we conclude that Ae. albopictus and Ae. koreicus are being passively spread primarily along the European route E35 from Italy to Germany, crossing the Alps, while Ae. japonicus has been expanding its range from northern Switzerland across the country most likely through active dispersal.


Asunto(s)
Aedes/clasificación , Aedes/fisiología , Monitoreo Epidemiológico , Mosquitos Vectores/fisiología , Aedes/virología , Animales , Europa (Continente) , Femenino , Especies Introducidas , Italia , Control de Mosquitos/instrumentación , Oviposición/fisiología , Suiza , Virus Zika
14.
PLoS Comput Biol ; 16(9): e1008190, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32976489

RESUMEN

Spatial repellents (SRs) reduce human-mosquito contact by preventing mosquito entrance into human-occupied spaces and interfering with host-seeking and blood-feeding. A new model to synthesize experimental data on the effects of transfluthrin on Aedes aegypti explores how SR effects interact to impact the epidemiology of diseases vectored by these mosquitoes. Our results indicate that the greatest impact on force of infection is expected to derive from the chemical's lethal effect but delayed biting and the negative effect this may have on the mosquito population could elicit substantial impact in the absence of lethality. The relative contributions of these effects depend on coverage, chemical dose, and housing density. We also demonstrate that, through an increase in the number of potentially infectious mosquito bites, increased partial blood-feeding and reduced exiting may elicit adverse impacts, which could offset gains achieved by other effects. Our analysis demonstrates how small-scale experimental data can be leveraged to derive expectations of epidemiological impact of SRs deployed at larger scales.


Asunto(s)
Aedes/microbiología , Repelentes de Insectos , Control de Mosquitos/métodos , Mosquitos Vectores , Aedes/virología , Animales , Ciclopropanos/farmacología , Fluorobencenos/farmacología
15.
PLoS Negl Trop Dis ; 14(9): e0008654, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32976503

RESUMEN

Effectively controlling vector mosquito populations while avoiding the development of resistance remains a prevalent and increasing obstacle to integrated vector management. Although, metallic nanoparticles have previously shown promise in controlling larval populations via mechanisms which are less likely to spur resistance, the impacts of such particles on life history traits and fecundity of mosquitoes are understudied. Herein, we investigate the chemically well-defined cerium oxide nanoparticles (CNPs) and silver-doped nanoceria (AgCNPs) for larvicidal potential and effects on life history traits and fecundity of Aedes (Ae.) aegypti mosquitoes. When 3rd instar larvae were exposed to nanoceria in absence of larval food, the mortality count disclosed significant activity of AgCNPs over CNPs (57.8±3.68% and 17.2±2.81% lethality, respectively) and a comparable activity to Ag+ controls (62.8±3.60% lethality). The surviving larvae showed altered life history traits (e.g., reduced egg hatch proportion and varied sex ratios), indicating activities of these nanoceria beyond just that of a larvicide. In a separate set of experiments, impacts on oocyte growth and egg generation resulting from nanoceria-laced blood meals were studied using confocal fluorescence microscopy revealing oocytes growth-arrest at 16-24h after feeding with AgCNP-blood meals in some mosquitoes, thereby significantly reducing average egg clutch. AgCNPs caused ~60% mortality in 3rd instar larvae when larval food was absent, while CNPs yielded only ~20% mortality which contrasts with a previous report on green-synthesized nanoceria and highlights the level of detail required to accurately report and interpret such studies. Additionally, AgCNPs are estimated to contain much less silver (0.22 parts per billion, ppb) than the amount of Ag+ needed to achieve comparable larvicidal activity (2.7 parts per million, ppm), potentially making these nanoceria ecofriendly. Finally, this work is the first study to demonstrate the until-now-unappreciated impacts of nanoceria on life history traits and interference with mosquito egg development.


Asunto(s)
Aedes/efectos de los fármacos , Cerio/farmacología , Fertilidad/efectos de los fármacos , Larva/efectos de los fármacos , Rasgos de la Historia de Vida , Animales , Femenino , Nanopartículas del Metal/química , Control de Mosquitos/métodos , Tamaño de la Partícula , Plata/farmacología
16.
Mem Inst Oswaldo Cruz ; 115: e190431, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32935748

RESUMEN

BACKGROUND: Long lasting insecticide-treated nets (LLINs) may be effective for vector control of cutaneous leishmaniasis (CL). Their efficacy, however, has not been sufficiently evaluated. OBJECTIVE: To evaluate the large-scale efficacy of LLINs on Lutzomyia longiflocosa entomological parameters up to two years post-intervention in the sub-Andean region of Colombia. METHODS: A matched-triplet cluster-randomised study of 21 rural settlements, matched by pre-intervention L. longiflocosa indoor density was used to compare three interventions: dip it yourself (DIY) lambda-cyhalothrin LLIN, deltamethrin LLIN, and untreated nets (control). Sand fly indoor density, feeding success, and parity were recorded using CDC light trap collections at 1, 6, 12, and 24 months post-intervention. FINDINGS: Both LLINs reduced significantly (74-76%) the indoor density and the proportion of fully engorged sand flies up to two years post-intervention without differences between them. Residual lethal effects of both LLINs and the use of all nets remained high throughout the two-year evaluation period. CONCLUSIONS: Both LLINs demonstrated high efficacy against L. longiflocosa indoors. Therefore, the deployment of these LLINs could have a significant impact on the reduction of CL transmission in the sub-Andean region. The DIY lambda-cyhalothrin kit may be used to convert untreated nets to LLINs increasing coverage.


Asunto(s)
Anopheles/efectos de los fármacos , Insectos Vectores/efectos de los fármacos , Mosquiteros Tratados con Insecticida , Insecticidas/administración & dosificación , Leishmaniasis Cutánea/prevención & control , Control de Mosquitos/métodos , Animales , Colombia , Resistencia a los Insecticidas , Leishmaniasis Cutánea/parasitología , Mosquitos Vectores , Población Rural
17.
PLoS Med ; 17(9): e1003248, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32946451

RESUMEN

BACKGROUND: Two billion long-lasting insecticidal nets (LLINs) have been procured for malaria control. A functional LLIN is one that is present, is in good physical condition, and remains insecticidal, thereby providing protection against vector-borne diseases through preventing bites and killing disease vectors. The World Health Organization (WHO) prequalifies LLINs that remain adequately insecticidal 3 years after deployment. Therefore, institutional buyers often assume that prequalified LLINs are functionally identical with a 3-year lifespan. We measured the lifespans of 3 LLIN products, and calculated their cost per year of functional life, to demonstrate the economic and public health importance of procuring the most cost-effective LLIN product based on its lifespan. METHODS AND FINDINGS: A randomised double-blinded trial of 3 pyrethroid LLIN products (10,571 nets in total) was conducted at 3 follow-up points: 10 months (August-October 2014), 22 months (August-October 2015), and 36 months (October-December 2016) among 3,393 households in Tanzania using WHO-recommended methods. Primary outcome was LLIN functional survival (LLIN present and in serviceable condition). Secondary outcomes were (1) bioefficacy and chemical content (residual insecticidal activity) and (2) protective efficacy for volunteers sleeping under the LLINs (bite reduction and mosquitoes killed). Median LLIN functional survival was significantly different between the 3 net products (p = 0.001): 2.0 years (95% CI 1.7-2.3) for Olyset, 2.5 years (95% CI 2.2-2.8) for PermaNet 2.0 (hazard ratio [HR] 0.73 [95% CI 0.64-0.85], p = 0.001), and 2.6 years (95% CI 2.3-2.8) for NetProtect (HR = 0.70 [95% CI 0.62-0.77], p < 0.001). Functional survival was affected by accumulation of holes, leading to users discarding nets. Protective efficacy also significantly differed between products as they aged. Equivalent annual cost varied between US$1.2 (95% CI $1.1-$1.4) and US$1.5 (95% CI $1.3-$1.7), assuming that each net was priced identically at US$3. The 2 longer-lived nets (PermaNet and NetProtect) were 20% cheaper than the shorter-lived product (Olyset). The trial was limited to only the most widely sold LLINs in Tanzania. Functional survival varies by country, so the single country setting is a limitation. CONCLUSIONS: These results suggest that LLIN functional survival is less than 3 years and differs substantially between products, and these differences strongly influence LLIN value for money. LLIN tendering processes should consider local expectations of cost per year of functional life and not unit price. As new LLIN products come on the market, especially those with new insecticides, it will be imperative to monitor their comparative durability to ensure that the most cost-effective products are procured for malaria control.


Asunto(s)
Mosquiteros Tratados con Insecticida/economía , Insecticidas/economía , Control de Mosquitos/métodos , Animales , Culicidae/efectos de los fármacos , Vectores de Enfermedades , Composición Familiar , Estudios de Seguimiento , Humanos , Resistencia a los Insecticidas/efectos de los fármacos , Mosquiteros Tratados con Insecticida/tendencias , Insecticidas/farmacología , Malaria/prevención & control , Control de Mosquitos/economía , Mosquitos Vectores/efectos de los fármacos , Piretrinas/farmacología , Tanzanía/epidemiología
18.
PLoS One ; 15(9): e0235548, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32946475

RESUMEN

We constructed an electric multi-rotor autonomous unmanned aerial system (UAS) to perform mosquito control activities. The UAS can be equipped with any of four modules for spraying larvicides, dropping larvicide tablets, spreading larvicide granules, and ultra-low volume spraying of adulticides. The larvicide module sprayed 124 µm drops at 591 mL/min over a 14 m swath for a total application rate of 1.6 L/ha. The tablet module was able to repeatedly deliver 40-gram larvicide tablets within 1.1 m of the target site. The granular spreader covered a 6 m swath and treated 0.76 ha in 13 min at an average rate of 1.8 kg/ha. The adulticide module produced 16 µm drops with an average deposition of 2.6 drops/mm2. UAS pesticide applications were made at rates prescribed for conventional aircraft, limited only by the payload capacity and flight time. Despite those limitations, this system can deliver pesticides with much greater precision than conventional aircraft, potentially reducing pesticide use. In smaller, congested environments or in programs with limited resources, UAS may be a preferable alternative to conventional aircraft.


Asunto(s)
Aeronaves , Culicidae , Seguimiento de Parámetros Ecológicos/instrumentación , Insecticidas/administración & dosificación , Control de Mosquitos/instrumentación , Animales , Larva
20.
PLoS Negl Trop Dis ; 14(9): e0008591, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32941432

RESUMEN

The reliance on blood is a limiting factor for mass rearing of mosquitoes for Sterile-Insect-Technique (SIT) and other mosquito-based control strategies. To solve this problem, we have developed SkitoSnack, a formulated diet for Aedes aegypti (L) mosquitoes, as an alternative for vertebrate blood. Here we addressed the question if long-term yellow fever mosquito culture with SkitoSnack resulted in changed life history traits and fitness of the offspring compared to blood-raised mosquitoes. We also explored if SkitoSnack is suitable to raise Asian tiger mosquitos, Aedes albopictus (L.), and the human bed bug, Cimex lectularius (L). We measured life history traits for 30th generation SkitoSnack-raised Ae. aegypti and 11th generation SkitoSnack-raised Ae. albopictus, and compared them with control mosquitoes raised on blood only. We compared meal preference, flight performance, and reproductive fitness in Ae. aegypti raised on SkitoSnack or blood. We also offered SkitoSnack to bed bug nymphs. We found that long-term culture with SkitoSnack resulted in mosquitoes with similar life history traits compared to bovine blood-raised mosquitoes in both species we studied. Also, Ae. aegypti mosquitoes raised on SkitoSnack had similar flight performance compared to blood raised mosquitoes, were still strongly attracted by human smell and had equal mating success. Minimal feeding occurred in bed bugs. Our results suggest that long-term culture with the blood-meal replacement SkitoSnack results in healthy, fit mosquitoes. Therefore, artificial diets like SkitoSnack can be considered as a viable alternative for vertebrate blood in laboratory mosquito culture as well as for mosquito mass production for Sterile-Insect-Technique mosquito control interventions. SkitoSnack was not suitable to induce engorgement of bed bugs.


Asunto(s)
Aedes/crecimiento & desarrollo , Chinches/crecimiento & desarrollo , Sustitutos Sanguíneos/farmacología , Conducta Alimentaria/fisiología , Mosquitos Vectores/crecimiento & desarrollo , Animales , Bovinos , Control de Mosquitos
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