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1.
Braz. j. biol ; 83: e240118, 2023. tab, graf
Artigo em Inglês | MEDLINE, LILACS, VETINDEX | ID: biblio-1278559

RESUMO

Abstract For many centuries human populations have been suffering and trying to fight with disease-bearing mosquitoes. Emerging and reemerging diseases such as Dengue, Zika, and Chikungunya affect billions of people around the world and recently has been appealing to control with chemical pesticides. Malathion (MT) is one of the main pesticides used against mosquitoes, the vectors of these diseases. This study aimed to assess cytotoxicity and mutagenicity of the malathion for the bioindicator Allium cepa L. using a multivariate and integrative approach. Moreover, an appendix table was compiled with all available literature of insecticides assessed by the Allium cepa system to support our discussion. Exposures during 48h to 0.5 mg mL-1 and 1.0 mg mL-1 MT were compared to the negative control (distilled water) and positive control (MMS solution at 10 mg L-1). The presence of chromosomal aberrations, micronuclei frequency, and mitotic index abnormalities was evaluated. Anaphase bridges were the alterations with higher incidence and presented a significantly elevated rate in the concentration of 0.5 mg mL-1, including when compared to the positive control. The integrative discriminant analysis summarizes that MT in assessed concentrations presented effects like the positive control, corroborating its potential of toxicity to DNA. Therefore, it is concluded that MT in its pure composition and in realistic concentrations used, has genotoxic potential in the biological assessment of A. cepa cells. The multivariate integrative analysis was fundamental to show a whole response of all data, providing a global view of the effect of MT on DNA.


Resumo Por muitos séculos, as populações humanas sofrem e tentam combater os mosquitos transmissores de doenças. Doenças emergentes e reemergentes como Dengue, Zika e Chikungunya afetam bilhões de pessoas em todo o mundo e, recentemente, vem apelando ao controle com pesticidas químicos. O Malation (MT) é um dos principais pesticidas usados ​​contra mosquitos, vetores dessas doenças. O objetivo deste estudo foi avaliar a citotoxicidade e a mutagenicidade do MT para o bioindicador Allium cepa L. usando uma abordagem multivariada e integrativa. Além disso, uma tabela suplementar foi compilada com toda a literatura disponível de inseticidas avaliada pelo sistema Allium cepa para apoiar nossa discussão. Exposições ao MT durante 48h a 0,5 mg mL-1 e 1,0 mg mL-1 foram comparadas a um controle negativo (água destilada) e um controle positivo (10 mg L-1 de MMS). Foram avaliadas a presença de aberrações cromossômicas, frequência de micronúcleos e anormalidades no índice mitótico. As pontes anafásicas foram as alterações com maior incidência e apresentaram uma taxa significativamente elevada na concentração de 0,5 mg mL-1, inclusive quando comparadas ao controle positivo. A análise discriminante integrativa resume que o MT nas concentrações avaliadas apresentou efeitos semelhantes ao controle positivo, corroborando seu potencial de toxicidade para o DNA. Portanto, conclui-se que o MT, em sua composição pura e nas concentrações realistas utilizadas, possui potencial genotóxico na avaliação biológica de células de A. cepa. A análise integrativa multivariada foi fundamental para mostrar uma resposta completa de todos os dados, fornecendo uma visão global do efeito da MT no DNA.


Assuntos
Humanos , Animais , Zika virus , Infecção por Zika virus , Inseticidas/toxicidade , Dano ao DNA , Aberrações Cromossômicas , Raízes de Plantas , Cebolas , Mosquitos Vetores , Malation/toxicidade , Índice Mitótico
2.
Braz. j. biol ; 83: e246230, 2023. tab, graf
Artigo em Inglês | MEDLINE, LILACS, VETINDEX | ID: biblio-1339369

RESUMO

Abstract Dengue fever vectored by the mosquito Aedes aegypti is one of the most rapidly spreading insect-borne diseases. Current reliance of dengue vector control is mostly on chemical insecticides. Growing insecticide resistance in the primary mosquito vector, Aedes aegypti, limits the effectiveness of vector control through chemical insecticides. These chemical insecticides also have negative environmental impacts on animals, plants and human health. Myco-biocontrol agents are naturally occurring organisms and are found to be less damaging to the environment as compared to chemical insecticides. In the present study, entomopathogenic potential of local strains of fungi isolated from soil was assessed for the control of dengue vector. Local fungal isolates presents better alternative to introducing a foreign biocontrol strain, as they may be better adapted to environmental conditions of the area to survive and may have more entomopathogenic efficacy against target organism. Larvicidal efficacy of Fusarium equiseti and Fusarium proliferatum was evaluated against Aedes aegypti. Local strains of F. equiseti (MK371718) and F. proliferatum (MK371715) were isolated from the soil of Changa Manga Forest, Pakistan by using insect bait method. Larvicidal activity of two Fusarium spp. was tested against forth instar larvae of A. aegypti in the laboratory, using concentrations 105, 106, 107 and 108 conidia /ml. LC50 values for F. equiseti after 24h, 48h, 72h and 96h of exposure were recorded as 3.8x 108, 2.9x107, 2.0x107, and 7.1x106 conidia /ml respectively while LC50 values for F. proliferatum were recorded as 1.21x108, 9.6x107, 4.2x107, 2.6x107 conidia /ml respectively after 24h, 48h, 72h and 96h of exposure. The results indicate that among two fungal strains F. equiseti was found to be more effective in terms of its larvicidal activity than F. proliferatum against larvae of A. aegypti.


Resumo A dengue transmitida pelo mosquito Aedes aegypti é uma das doenças transmitidas por insetos de propagação mais rápida. A dependência atual do controle do vetor da dengue é principalmente de inseticidas químicos. O aumento da resistência a inseticidas no principal vetor do mosquito, Aedes aegypti, limita a eficácia do controle do vetor por meio de inseticidas químicos. Esses inseticidas químicos também têm impactos ambientais negativos sobre os animais, plantas e saúde humana. Os agentes de micobiocontrole são organismos que ocorrem naturalmente e são menos prejudiciais ao meio ambiente em comparação com os inseticidas químicos. No presente estudo, avaliou-se o potencial entomopatogênico de cepas locais de fungos isolados do solo para o controle do vetor da dengue. Isolados de fungos locais apresentam melhor alternativa para a introdução de uma cepa de biocontrole estrangeira, pois podem ser mais bem adaptados às condições ambientais da área para sobreviver e podem ter maior eficácia entomopatogênica contra o organismo-alvo. A eficácia larvicida de Fusarium equiseti e Fusarium proliferatum foi avaliada contra Aedes aegypti. Cepas locais de F. equiseti (MK371718) e F. proliferatum (MK371715) foram isoladas do solo de Changa Manga Forest, Paquistão, usando o método de isca para insetos. Atividade larvicida de dois Fusarium spp. foi testado contra larvas de quarto ínstar de A. aegypti em laboratório, nas concentrações 105, 106, 107 e 108 conídios / ml. Os valores de LC50 para F. equiseti após 24 h, 48 h, 72 h e 96 h de exposição foram registrados como 3,8x 108, 2,9x107, 2,0x107 e 7,1x106 conídios / ml, respectivamente, enquanto os valores de LC50 para F. proliferatum foram registrados como 1,21x108, 9,6 x107, 4,2x107, 2,6x107 conídios / ml, respectivamente, após 24 h, 48 h, 72 h e 96 h de exposição. Os resultados indicam que entre duas cepas de fungos F. equiseti se mostrou mais eficaz em termos de atividade larvicida do que F. proliferatum contra larvas de A. aegypti.


Assuntos
Humanos , Animais , Aedes , Fusarium , Inseticidas/farmacologia , Paquistão , Solo , Extratos Vegetais , Florestas , Mosquitos Vetores , Larva
3.
Am J Trop Med Hyg ; 2022 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-35436764

RESUMO

Dengue is a public health problem in Colombia and in the municipality of Girardot, an area of high risk for dengue transmission. We present the results of an economic evaluation from the societal perspective and 1-year time horizon comparing the regular control program for dengue prevention versus an intervention that comprised an environmental management strategy by covering the most Aedes aegypti productive breeding sites with insecticide covers, community actions, and educational activities. The effectiveness of the intervention was measured as the reduction in probability of dengue infection obtained from a community trial. Resource use was estimated from clinical records that were validated by clinical experts; unit costs were taken from national tariffs. Patient costs were obtained from a household survey. We found that the intervention generated an additional cost of USD20.9 per household and an incremental effectiveness of 0.00173 (reduction in the probability of reported dengue cases). Overall, both alternatives generate similar effectiveness, but the new intervention was associated with increasing costs. We conclude the new intervention is a potentially cost-effective option in areas where high prevalence of dengue exists.

4.
Cad Saude Publica ; 38(3): e00110121, 2022.
Artigo em Português | MEDLINE | ID: mdl-35384994

RESUMO

The study aimed to present the methodological proposal entitled "Prompt Response", modelled in the cities of Belo Horizonte (Minas Gerais State) and Natal (Rio Grande do Norte State), Brazil. The proposal aims to identify and demarcate priority areas for timely targeting of surveillance activities, aiming to reduce the intensity and velocity in the spread of epidemics in endemic urban areas. The methodology uses three variables that represent the necessary causes for the production and reproduction of dengue: notified cases (virus), Aedes eggs (vector), and population (host). This was an ecological study that used data from three information planes aggregated in finer temporal and spatial scales of 3 to 4 weeks and 400 to 600-meter grids, respectively. The prompt response areas were defined by Scan statistical analysis with definition of simultaneous spatial clusters for the three planes via the SaTScan program. In Natal, the areas defined as prompt response occupied, on average, 15.2% of the city's territory and concentrated 67.77% of the dengue cases in the period following demarcation of the prompt response areas. In Belo Horizonte, the observed proportions were 64.16% of cases in 23.23% of the territory. These results were obtained in two cities with different socioenvironmental and geographic realities and distinct epidemiological profiles, indicating that the methodology can be applied to different urban realities, allowing control programs to concentrate on reduced portions of the territory and impacting a high percentage of cases in timely fashion.


O objetivo deste trabalho foi apresentar a proposta metodológica denominada de "Pronta Resposta" modelada nas cidades de Belo Horizonte (Minas Gerais) e Natal (Rio Grande do Norte), Brasil. A metodologia visa identificar e delimitar áreas prioritárias para o direcionamento das ações de vigilância em tempo oportuno, buscando a redução da intensidade e velocidade da dispersão de epidemias em áreas urbanas endêmicas. Para tanto, a metodologia utiliza três variáveis, que representam as causas necessárias para a produção e reprodução da dengue: casos notificados (vírus), ovos de Aedes (vetor) e população (hospedeiro). Trata-se de um estudo ecológico que utilizou os dados dos três planos de informações agregados em escalas temporais e espaciais mais finas, de três a quatro semanas e grades de 400 a 600 metros respectivamente. As áreas de pronta resposta foram definidas por meio de análise estatística de varredura Scan, com definição de clusters espaciais simultâneos para os três planos por meio do programa SaTScan. Os resultados observados foram: na cidade de Natal, as áreas definidas como pronta resposta ocuparam em média 15,2% do território do município e concentraram 67,77% dos casos de dengue do período posterior ao utilizado na delimitação das áreas de pronta resposta, e em Belo Horizonte, os números observados foram de 64,16% dos casos em 23,23% do território. Esses resultados foram obtidos em duas cidades com realidades socioambientais e geográficas diferentes e com perfis epidemiológicos também distintos, apontando que a metodologia pode ser aplicada em diferentes realidades urbanas, criando a possibilidade de os programas de controle atuarem em porções reduzidas do território e impactar num alto percentual de casos em tempo oportuno.


El objetivo del trabajo fue presentar la propuesta metodológica, denominada de "Resposta Rápida", modelada en las ciudades de Belo Horizonte (Minas Gerais) y Natal (Rio Grande do Norte), Brasil. Esta última tiene como meta identificar y delimitar áreas prioritarias para la ejecución de acciones de vigilancia en el momento oportuno, buscando la reducción de la intensidad y velocidad de la dispersión de epidemias en áreas urbanas endémicas. Para tal fin, la metodología utiliza tres variables, que representan las causas necesarias para la producción y reproducción del dengue: casos notificados (virus), huevos de Aedes (vector) y población (huésped). Se trata de un estudio ecológico que utilizó los datos de los tres planos de información agregados en escalas temporales y espaciales más finas, de 3 a 4 semanas y tablas de 400 a 600 metros respectivamente. Las áreas de respuesta rápida se definieron a través del análisis estadístico de exploración Scan, con definición de clústeres espaciales simultáneos para los tres planos mediante el programa SaTScan. Los resultados observados fueron: en la ciudad de Natal, las áreas definidas como de respuesta rápida ocuparon de media un 15,2% del territorio del municipio y concentraron un 67,77% de los casos de dengue del período posterior al utilizado en la delimitación de las áreas de respuesta rápida y, en Belo Horizonte, los números observados fueron un 64,16% de los casos en un 23,23% del territorio. Estos resultados se obtuvieron en dos ciudades con realidades socioambientales y geográficas diferentes y con perfiles epidemiológicos también distintos, apuntando que la metodología se puede aplicar en diferentes realidades urbanas. Dando la posibilidad de que los programas de control actúen en secciones reducidas del territorio e impactar en un alto porcentaje de casos en el momento oportuno.


Assuntos
Aedes , Infecções por Arbovirus , Dengue , Aedes/fisiologia , Animais , Infecções por Arbovirus/diagnóstico , Infecções por Arbovirus/epidemiologia , Brasil/epidemiologia , Dengue/epidemiologia , Humanos , Mosquitos Vetores
5.
PLoS Negl Trop Dis ; 16(4): e0010324, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35471983

RESUMO

BACKGROUND: The combination of Wolbachia-based incompatible insect technique (IIT) and radiation-based sterile insect technique (SIT) can be used for population suppression of Aedes aegypti. Our main objective was to evaluate whether open-field mass-releases of wAlbB-infected Ae. aegypti males, as part of an Integrated Vector Management (IVM) plan led by the Mexican Ministry of Health, could suppress natural populations of Ae. aegypti in urbanized settings in south Mexico. METHODOLOGY/PRINCIPAL FINDINGS: We implemented a controlled before-and-after quasi-experimental study in two suburban localities of Yucatan (Mexico): San Pedro Chimay (SPC), which received IIT-SIT, and San Antonio Tahdzibichén used as control. Release of wAlbB Ae. aegypti males at SPC extended for 6 months (July-December 2019), covering the period of higher Ae. aegypti abundance. Entomological indicators included egg hatching rates and outdoor/indoor adult females collected at the release and control sites. Approximately 1,270,000 lab-produced wAlbB-infected Ae. aegypti males were released in the 50-ha treatment area (2,000 wAlbB Ae. aegypti males per hectare twice a week in two different release days, totaling 200,000 male mosquitoes per week). The efficacy of IIT-SIT in suppressing indoor female Ae. aegypti density (quantified from a generalized linear mixed model showing a statistically significant reduction in treatment versus control areas) was 90.9% a month after initiation of the suppression phase, 47.7% two months after (when number of released males was reduced in 50% to match local abundance), 61.4% four months after (when initial number of released males was re-established), 88.4% five months after and 89.4% at six months after the initiation of the suppression phase. A proportional, but lower, reduction in outdoor female Ae. aegypti was also quantified (range, 50.0-75.2% suppression). CONCLUSIONS/SIGNIFICANCE: Our study, the first open-field pilot implementation of Wolbachia IIT-SIT in Mexico and Latin-America, confirms that inundative male releases can significantly reduce natural populations of Ae. aegypti. More importantly, we present successful pilot results of the integration of Wolbachia IIT-SIT within a IVM plan implemented by Ministry of Health personnel.


Assuntos
Aedes , Infertilidade Masculina , Wolbachia , Animais , Feminino , Humanos , Insetos , Masculino , México , Controle de Mosquitos/métodos , Mosquitos Vetores , Projetos Piloto
6.
J Am Mosq Control Assoc ; 38(1): 59-69, 2022 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-35276730

RESUMO

Insecticide use is the primary method of attempting to reduce or control the spread of mosquito-borne diseases. Insecticide resistance is a major concern as resistance will limit the efficacy of vector-control efforts. The lower Rio Grande Valley region of South Texas has had autochthonous transmission of multiple mosquito-borne diseases including those caused by dengue virus, chikungunya virus, and Zika virus. However, the current status of mosquito resistance to commonly used pesticides in this region is unknown. In this study, we collected field samples from multiple municipalities in South Texas and assessed resistance using the Centers for Disease Control and Prevention bottle bioassay. All populations exhibited characteristics of resistance, and permethrin was the most effective insecticide with an average mortality rate of 44.78%. Deltamethrin and sumethrin had significantly lower mortality rates of 20.31% and 32.16%, respectively, although neither of these insecticides are commonly used for vector-control activities in this region. Depending on which insecticide was used, there was little significance between each of the 7 cities. Seasonal variation in resistance was observed among the collection sites. Both deltamethrin and sumethrin exhibited an increase in susceptibility over the course of 10 months, while permethrin exhibited a decrease in susceptibility. These data highlight the need for further studies to determine if variations in resistance observed are repeated. The data and future findings may be useful in determining the most effective strategies for pesticide use and rotation.


Assuntos
Aedes , Inseticidas , Piretrinas , Infecção por Zika virus , Zika virus , Animais , Cidades , Resistência a Inseticidas , Inseticidas/farmacologia , México , Mosquitos Vetores , Permetrina , Texas , Infecção por Zika virus/prevenção & controle
7.
PLoS Negl Trop Dis ; 16(3): e0010135, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35245284

RESUMO

BACKGROUND: Following earlier trials indicating that their potential in dengue vector control was constrained by housing structure, a large-scale cluster-randomized trial of insecticide treated curtains (ITCs) and water jar covers (ITJCs) was undertaken in Venezuela. METHODS: In Trujillo, Venezuela, 60 clusters (6223 houses total) were randomized so that 15 clusters each received either PermaNet insecticide-treated window curtains (ITCs), permanent insecticide-treated water storage jar covers (ITJCs), a combination of both ITCs and ITJCs, or no insecticide treated materials (ITMs). A further 15 clusters located at least 5km from the edge of the study site were selected to act as an external control. Entomological surveys were carried out immediately before and after intervention, and then at 6-month intervals over the following 27 months. The Breteau and House indices were used as primary outcome measures and ovitrap indices as secondary. Negative binomial regression models were used to compare cluster-level values of these indices between the trial arms. RESULTS: Reductions in entomological indices followed deployment of all ITMs and throughout the trial, indices in the external control arm remained substantially higher than in the ITM study arms including the internal control. Comparing the ratios of between-arm means to summarise the entomological indices throughout the study, the combined ITC+ITJC intervention had the greatest impact on the indices, with a 63% difference in the pupae per person indices between the ITC+ITJC arm and the internal control. However, coverage had fallen below 60% by 14-months post-intervention and remained below 40% for most of the remaining study period. CONCLUSIONS: ITMs can impact dengue vector populations in the long term, particularly when ITCs and ITJCs are deployed in combination. TRIAL REGISTRATION: ClinicalTrials.gov ISRCTN08474420; www.isrctn.com.


Assuntos
Aedes , Dengue , Inseticidas , Animais , Dengue/prevenção & controle , Humanos , Controle de Mosquitos , Mosquitos Vetores , Venezuela , Água
8.
Sci Rep ; 12(1): 4047, 2022 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-35260697

RESUMO

The use of lure-and-kill, large-volume ovitraps to control Aedes aegypti and Aedes albopictus populations has shown promise across multiple designs that target gravid females (adulticidal) or larvae post-oviposition (larvicidal). Here we report on a pilot trial to deploy 10 L yeast-baited ovitraps at select sites in Curepe, Trinidad, West Indies during July to December, 2019. Oviposition rates among ovitraps placed in three Treatment sites were compared to a limited number of traps placed in three Control areas (no Aedes management performed), and three Vector areas (subjected to standard Ministry of Health, Insect Vector Control efforts). Our goal was to gain baseline information on efforts to saturate the Treatment sites with ovitraps within 20-25 m of each other and compare oviposition rates at these sites with background oviposition rates in Control and Vector Areas. Although yeast-baited ovitraps were highly attractive to gravid Aedes females, a primary limitation encountered within the Treatment sites was the inability to gain access to residential compounds for trap placement, primarily due to residents being absent during the day. This severely limited our intent to saturate these areas with ovitraps, indicating that future studies must include plans to account for these inaccessible zones during trap placement.


Assuntos
Aedes , Animais , Feminino , Controle de Mosquitos , Mosquitos Vetores , Oviposição , Saccharomyces cerevisiae , Trinidad e Tobago
9.
Am J Trop Med Hyg ; 2022 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-35292593

RESUMO

Dengue cases and deaths occur frequently in Mexico, although the trend is not uniform across the country. We performed a Spatio-temporal analysis of dengue cases and deaths in Mexico from 2007 to 2020, and clustered states according to whether there was a low, moderate, or high risk of dengue. A total of 501,600 confirmed dengue cases were registered from 2007 to 2020, with 378,122 cases classified as dengue fever (DF) and 123,478 cases classified as dengue hemorrhagic fever (DHF). For each confirmed case, there were 4.68 probable cases. There were 1,230 dengue deaths, with highest numbers reported in 2009, 2012, 2013, and 2019. The number of deaths had a significant correlation (P ≤ 0.01) with DF (r = 0.82), DHF (r = 0.94), and probable dengue cases (r = 0.84). States were clustered using Machine Learning technique according to select indices associated with dengue. Cluster 1 (low risk) primarily contained states in the northwest, northcentral, and east. Cluster 2 (moderate risk) includes states in the northeast. Cluster 3 (high risk) mostly contained coastal states in the southeast, southwest, and west. The generation of the clusters was supported by the Kruskal-Wallis test. A significant difference was found in the incidence, mortality rates, and case-fatality rates of dengue among the clusters (P ≤ 0.01). Notably, cluster 3 contributed 71.4% of the confirmed cases and 89.2% of the deaths. Public health and vector control strategies designed to mitigate the burden of dengue in Mexico should consider the states in cluster 3 as high priority areas.

10.
Rev Soc Bras Med Trop ; 55: e0553, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35239912

RESUMO

BACKGROUND: Chagas disease (CD) is caused by the flagellate protozoan Trypanosoma cruzi and can be carried by different species of triatomines, including Rhodnius neglectus, which is wild, well distributed in Brazil, and has formed colonies in palm trees located in urban areas of municipalities in the state of São Paulo. Chemical control has been routinely used to reduce population density, but each year, there has been an increase in species dispersion and density. This study aimed to evaluate the susceptibility of insects to insecticides used in control. METHODS: The reference population was collected from Araçatuba municipality, Nilce Maia. Dilutions of deltamethrin were prepared and applied to the back of the first-stage nymphs, which were biologically synchronized. The control group received pure acetone only. Mortality was assessed after 72 h. RESULTS: The mortality rate with respect to diagnostic dose was 100%. The susceptibility profile observed for this population showed RR50 ranging from 1.76 to 3.632. CONCLUSIONS: The populations were susceptible to the insecticides tested. It is possible that the insecticide residual effect on this ecotope has decreased the lifespan, and controlling failures may be the cause of recolonization in this environment.


Assuntos
Doença de Chagas , Inseticidas , Rhodnius , Trypanosoma cruzi , Animais , Brasil/epidemiologia , Insetos Vetores , Inseticidas/farmacologia
11.
Trials ; 23(1): 185, 2022 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-35236394

RESUMO

BACKGROUND: Arboviruses transmitted by Aedes aegypti including dengue, Zika, and chikungunya are a major global health problem, with over 2.5 billion at risk for dengue alone. There are no licensed antivirals for these infections, and safe and effective vaccines are not yet widely available. Thus, prevention of arbovirus transmission by vector modification is a novel approach being pursued by multiple researchers. However, the field needs high-quality evidence derived from randomized, controlled trials upon which to base the implementation and maintenance of vector control programs. Here, we report the EVITA Dengue trial design (DMID 17-0111), which assesses the efficacy in decreasing arbovirus transmission of an innovative approach developed by the World Mosquito Program for vector modification of Aedes mosquitoes by Wolbachia pipientis. METHODS: DMID 17-0111 is a cluster-randomized trial in Belo Horizonte, Brazil, with clusters defined by primary school catchment areas. Clusters (n = 58) will be randomized 1:1 to intervention (release of Wolbachia-infected Aedes aegypti mosquitoes) vs. control (no release). Standard vector control activities (i.e., insecticides and education campaigns for reduction of mosquito breeding sites) will continue as per current practice in the municipality. Participants (n = 3480, 60 per cluster) are children aged 6-11 years enrolled in the cluster-defining school and living within the cluster boundaries who will undergo annual serologic surveillance for arboviral infection. The primary objective is to compare sero-incidence of arboviral infection between arms. DISCUSSION: DMID 17-0111 aims to determine the efficacy of Wolbachia-infected mosquito releases in reducing human infections by arboviruses transmitted by Aedes aegypti and will complement the mounting evidence for this method from large-scale field releases and ongoing trials. The trial also represents a critical step towards robustness and rigor for how vector control methods are assessed, including the simultaneous measurement and correlation of entomologic and epidemiologic outcomes. Data from this trial will inform further the development of novel vector control methods. TRIAL REGISTRATION: ClinicalTrials.gov NCT04514107 . Registered on 17 August 2020 Primary sponsor: National Institute of Health, National Institute of Allergy and Infectious Diseases.


Assuntos
Aedes , Vírus da Dengue , Dengue , Wolbachia , Infecção por Zika virus , Zika virus , Animais , Brasil/epidemiologia , Criança , Dengue/epidemiologia , Dengue/prevenção & controle , Humanos , Incidência , Mosquitos Vetores , Infecção por Zika virus/epidemiologia
12.
Rev Saude Publica ; 56: 1, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35239924

RESUMO

OBJECTIVE: To perform an entomological survey, evaluating the circulation of Leishmania spp. in sand flies captured from the new foci of visceral leishmaniasis (VL) in the coastal region of São Paulo state. METHODS: Sand flies were captured from November 2016 to September 2018 using light traps of the Centers for Disease Control (CDC), in the neighborhood where VL cases were reported. Leishmania spp. circulation was evaluated by gut dissection and molecular analysis of the females captured. RESULTS: Nyssomyia intermedia was the more frequent species (90,7%) within the 1,203 sand flies captured. We found no flagellates in dissected females, but two pools containing females of Ny. intermedia presented DNA of L. infantum. CONCLUSION: Our results suggest that Ny. intermedia might be involved in the establishment of this new VL focus in Sao Paulo. However, before incriminating this species as a L. infantum vector, further studies should investigate other vectorial capacity parameters, including competence, survival, and feeding habits.


Assuntos
Leishmaniose Visceral , Psychodidae , Animais , Brasil/epidemiologia , Cidades , Feminino , Insetos Vetores , Leishmaniose Visceral/epidemiologia , Psychodidae/genética
13.
Malar J ; 21(1): 72, 2022 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-35246147

RESUMO

BACKGROUND: The STECLA strain of Anopheles albimanus has been in continuous colony for many years and is the reference strain on which genomic studies for the species are based. Recently, the STECLA strain was demonstrated to be much less susceptible to ivermectin ingested in a blood meal (4-day LC50 of 1468 ng/ml) than all other Anopheles species tested to-date (LC50 values range from 7 to 56 ng/ml). The ability of An. albimanus to survive ingestion of ivermectin at concentrations far beyond that typically found in the blood of ivermectin-treated people or livestock (i.e., 30-70 ng/ml) could invalidate the use of ivermectin as a malaria vector control strategy in areas where An. albimanus is a primary vector. METHODS: To investigate this, host-seeking An. albimanus were captured in northern Belize and used in membrane feeding bioassays of ivermectin, employing the same methods as described earlier with the STECLA strain. RESULTS: Field-collected An. albimanus in Belize were 55 times more susceptible to ingested ivermectin than were the STECLA reference strain. Oral susceptibility to ivermectin in wild An. albimanus from Belize (4-day LC50 of 26 ng/ml) was equivalent to that of other Anopheles species tested. CONCLUSIONS: Contrary to initial assessments using a highly inbred strain of mosquito, laboratory studies using a field population indicate that ivermectin treatment of livestock could reduce An. albimanus populations in areas of Central America and the Caribbean where malaria transmission may occur. Toxicity screening of ivermectin and other systemic parasiticides for malaria control should examine wild populations of the vector species being targeted.


Assuntos
Anopheles , Malária , Animais , Belize , Humanos , Ivermectina/farmacologia , Laboratórios , Mosquitos Vetores
14.
Emerg Infect Dis ; 28(4): 701-706, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35318912

RESUMO

Arbovirus epidemiology lacks efficient and timely surveillance systems with accurate outbreak alert signals. We devised a citywide integrated surveillance system combining entomologic, epidemiologic, and entomo-virologic data gathered during 2017-2020 in Foz do Iguaçu, Brazil. We installed 3,476 adult mosquito traps across the city and inspected traps every 2 months. We compared 5 entomologic indices: traditional house and Breteau indices for larval surveys and trap positivity, adult density, and mosquitoes per inhabitant indices for adult trapping. We screened for dengue, Zika, and chikungunya viruses in live adult Aedes aegypti mosquitoes collected from traps. Indices based on adult mosquito sampling had higher outbreak predictive values than larval indices, and we were able to build choropleth maps of infestation levels <36 h after each round of trap inspection. Locating naturally infected vectors provides a timely support tool for local public health managers to prioritize areas for intervention response to prevent virus outbreaks.


Assuntos
Aedes , Arbovírus , Infecção por Zika virus , Zika virus , Animais , Brasil/epidemiologia , Mosquitos Vetores , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/prevenção & controle
15.
Artigo em Inglês | MEDLINE | ID: mdl-35270552

RESUMO

Residents of informal settlements, the world over, suffer consequences due to the lack of drainage and greywater management, impacting human and environmental health. In Brazil, the presence of the Aedes aegypti mosquito in urban areas promotes infections of the Zika virus as well as companion viruses, such as dengue, chikungunya and yellow fever. By using observation and interviews with the community, this paper shows how a simple sustainable drainage system approach could prevent the accumulation of on-street standing water, and thus reduce opportunities for the mosquito to breed and reduce infection rates. During the interview phase, it became apparent that underlying misinformation and misunderstandings prevail related to existing environmental conditions in favelas and the role of the mosquito in infecting residents. This inhibits recommendations made by professionals to reduce breeding opportunities for the disease vector. Whilst unrest is an issue in favelas, it is not the only issue preventing the human right to reliable, safe sanitation, including drainage. In "pacified" favelas which may be considered safe(r), the infrastructure is still poor and is not connected to the city-wide sanitation/treatment networks.


Assuntos
Aedes , Vírus da Dengue , Dengue , Infecção por Zika virus , Zika virus , Animais , Brasil , Vetores de Doenças , Humanos , Mosquitos Vetores , Infecção por Zika virus/prevenção & controle
16.
BMC Public Health ; 22(1): 255, 2022 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-35135522

RESUMO

BACKGROUND: Since the 1980s, when dengue was reintroduced in Brazil, outbreaks and epidemics caused by different arbovirus strains transmitted by vector mosquitoes such as Aedes aegypti have been an annual occurrence. The aim of this study was to evaluate the behavioural change of high school students and teachers who participated in an educational intervention for the prevention and vector control of arboviral diseases. METHODS: In this school-based intervention, a self-reported questionnaire was used in a pre-post intervention methodology to assess environmental risk factors, sociodemographic variables and to measure attitudes and behaviours. In all, 883 high school students and teachers from the city of Campina Grande, in the state of Paraíba, northeastern Brazil, participated. The e-health intervention consisted of a competition between schools to comply with preventive actions via content production for social networks, and the monitoring was performed over a period of three months through the ZikaMob software developed by the researchers. RESULTS: Out of the 883 survey participants, 690 were students ranging in age from 14 to 41 years, with an average of 17 ± 2 years; and 193 were teachers from 22 to 64 years old, averaging 38 ± 9 years. The analysis of the data shows that significant differences in most of the target behaviours were apparent after the intervention, with an increase of about 10% in the performance of inspection actions; a 7% greater separation of recyclables and a 40% increase in the screening of windows among students. Students showed lower fear of, and a lower self-perception of the risk of, acquiring arboviruses than teachers on average. CONCLUSIONS: ZikaMob is an innovative strategy with the potential to be replicated in any location that has an internet network and can involve an unlimited number of participants.


Assuntos
Aedes , Infecções por Arbovirus , Arbovírus , Dengue , Adolescente , Adulto , Animais , Infecções por Arbovirus/epidemiologia , Infecções por Arbovirus/prevenção & controle , Brasil/epidemiologia , Dengue/epidemiologia , Dengue/prevenção & controle , Humanos , Pessoa de Meia-Idade , Mosquitos Vetores , Adulto Jovem
17.
Trop Biomed ; 39(1): 1-10, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-35225294

RESUMO

The present study aimed to identify larval trematodes shed by snails found in water bodies used by urban communities in a former schistosomiasis endemic area in the state of Piauí, in the Brazilian semiarid region. A malacological survey was performed followed by analysis of the cercariae shed by the snails after light exposure. Biomphalaria straminea specimens (n=1,224) were obtained from all seven collection sites. Cercariae shed by snails were i) single tailed, in which one type of cercariae was identified ( Echinostoma cercariae), and ii) with bifurcated tail (brevifurcate apharyngeate distome, brevifurcate pharyngeate distome, and longifurcate pharyngeate distome [strigeocercaria]). Brevifurcate apharyngeate distome were further examined and the presence of spikes in swimming membranes enabled the identification of Spirorchiidae cercariae in all individuals, demonstrating the absence of cercariae compatible with Schistosoma mansoni . Nevertheless, the accurate diagnosis of S. mansoni circulation in former endemic areas is still necessary.


Assuntos
Biomphalaria , Esquistossomose , Animais , Biomphalaria/parasitologia , Brasil , Vetores de Doenças , Larva , Schistosoma mansoni , Esquistossomose/epidemiologia , Esquistossomose/prevenção & controle , Esquistossomose/transmissão
18.
BMJ Open ; 12(1): e050991, 2022 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-35105618

RESUMO

OBJECTIVE: The World Health Organization declared a Public Health Emergency of International Concern following the rapid emergence of neonatal microcephaly in Brazil during the 2015-2016 Zika virus (ZIKV) epidemic. In response, a national campaign sought to control Aedes mosquito populations and reduce ZIKV transmission. Achieving adherence to vector control or mosquito-bite reduction behaviours, including the use of topical mosquito repellents, is challenging. Coproduction of research at the community level is needed to understand and mitigate social determinants of lower engagement with Aedes preventive measures, particularly within disempowered groups. DESIGN: In 2017, the Zika Preparedness Latin America Network (ZikaPLAN) conducted a qualitative study to understand individual and community level experiences of ZIKV and other mosquito-borne disease outbreaks. Presented here is a thematic analysis of 33 transcripts from community focus groups and semistructured interviews, applying the Health Belief Model (HBM) to elaborate knowledge, attitudes and perceptions of ZIKV and vector control strategies. PARTICIPANTS: 120 purposively sampled adults of approximate reproductive age (18-45); 103 women participated in focus groups and 17 men in semistructured interviews. SETTING: Two sociopolitically and epidemiologically distinct cities in Brazil: Jundiaí (57 km north of São Paolo) and Salvador (Bahia state capital). RESULTS: Four key and 12 major themes emerged from the analysis: (1) knowledge and cues to action; (2) attitudes and normative beliefs (perceived threat, barriers, benefits and self-efficacy); (3) behaviour change (household prevention and community participation); and (4) community preferences for novel repellent tools, vector control strategies and ZIKV messaging. CONCLUSIONS: Common barriers to repellent adherence were accessibility, appearance and effectiveness. A strong case is made for the transferability of the HBM to inform epidemic preparedness for mosquito-borne disease outbreaks at the community level. Nationally, a health campaign targeting men is recommended, in addition to local mobilisation of funding to strengthen surveillance, risk communication and community engagement.


Assuntos
Infecção por Zika virus , Zika virus , Adulto , Animais , Brasil/epidemiologia , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Recém-Nascido , Masculino , Mosquitos Vetores , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/prevenção & controle
19.
PLoS Genet ; 18(2): e1010019, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35120121

RESUMO

Accurate prediction of vectors dispersal, as well as identification of adaptations that allow blood-feeding vectors to thrive in built environments, are a basis for effective disease control. Here we adopted a landscape genomics approach to assay gene flow, possible local adaptation, and drivers of population structure in Rhodnius ecuadoriensis, an important vector of Chagas disease. We used a reduced-representation sequencing technique (2b-RADseq) to obtain 2,552 SNP markers across 272 R. ecuadoriensis samples from 25 collection sites in southern Ecuador. Evidence of high and directional gene flow between seven wild and domestic population pairs across our study site indicates insecticide-based control will be hindered by repeated re-infestation of houses from the forest. Preliminary genome scans across multiple population pairs revealed shared outlier loci potentially consistent with local adaptation to the domestic setting, which we mapped to genes involved with embryogenesis and saliva production. Landscape genomic models showed elevation is a key barrier to R. ecuadoriensis dispersal. Together our results shed early light on the genomic adaptation in triatomine vectors and facilitate vector control by predicting that spatially-targeted, proactive interventions would be more efficacious than current, reactive approaches.


Assuntos
Doença de Chagas/epidemiologia , Doença de Chagas/genética , Rhodnius/genética , Adaptação Biológica/genética , Animais , Vetores de Doenças , Ecossistema , Equador/epidemiologia , Expressão Gênica/genética , Perfilação da Expressão Gênica/métodos , Fluxo Gênico , Insetos Vetores/genética , Metagenômica/métodos , Polimorfismo de Nucleotídeo Único/genética , Densidade Demográfica , Rhodnius/patogenicidade , Transcriptoma/genética , Trypanosoma cruzi/genética
20.
PLoS One ; 17(2): e0263465, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35143523

RESUMO

BACKGROUND: Although domestic infestations by Triatoma infestans have been successfully controlled across Latin America, in areas of the Gran Chaco region, recurrent post-spraying house colonization continues to be a significant challenge, jeopardizing Chagas disease vector control and maintaining active Trypanosoma cruzi transmission. METHODOLOGY/PRINCIPAL FINDINGS: To investigate the dynamics of triatomine reinfestation in a rural area of the Paraguayan Chaco, genetic characterization (based on 10 microsatellite loci and cytochrome B sequence polymorphisms) was performed on baseline and reinfestant T. infestans (n = 138) from four indigenous communities and adjacent sylvatic sites. House quality and basic economic activities were assessed across the four communities. Significant genetic differentiation was detected among all baseline triatomine populations. Faster reinfestation was observed in the communities with higher infestation rates pre-spraying. Baseline and reinfestant populations from the same communities were not genetically different, but two potentially distinct processes of reinfestation were evident. In Campo Largo, the reinfestant population was likely founded by domestic survivor foci, with reduced genetic diversity relative to the baseline population. However, in 12 de Junio, reinfestant bugs were likely derived from different sources, including survivors from the pre-spraying population and sympatric sylvatic bugs, indicative of gene-flow between these habitats, likely driven by high human mobility and economic activities in adjacent sylvatic areas. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that sylvatic T. infestans threatens vector control strategies, either as a reinfestation source or by providing a temporary refuge during insecticide spraying. Passive anthropogenic importation of T. infestans and active human interactions with neighboring forested areas also played a role in recolonization. Optimization of spraying, integrated community development and close monitoring of sylvatic areas should be considered when implementing vector control activities in the Gran Chaco.


Assuntos
Doença de Chagas/prevenção & controle , Controle de Insetos , Insetos Vetores/genética , Triatoma/genética , Animais , Doença de Chagas/epidemiologia , Doença de Chagas/transmissão , Fluxo Gênico , Genótipo , Controle de Insetos/métodos , Inseticidas , Paraguai/epidemiologia , Prevalência
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