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de Oliveira JC, de Melo Katak R, Muniz VA, de Oliveira MR, Rocha EM, da Silva WR, do Carmo EJ, Roque RA, Marinotti O, Terenius O, Astolfi-Filho S. Bacteria isolated from Aedes aegypti with potential vector control applications. J Invertebr Pathol 2024; 204:108094. [PMID: 38479456 DOI: 10.1016/j.jip.2024.108094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 02/13/2024] [Accepted: 03/10/2024] [Indexed: 03/27/2024]
Abstract
Highly anthropophilic and adapted to urban environments, Aedes aegypti mosquitoes are the main vectors of arboviruses that cause human diseases such as dengue, zika, and chikungunya fever, especially in countries with tropical and subtropical climates. Microorganisms with mosquitocidal and larvicidal activities have been suggested as environmentally safe alternatives to chemical or mechanical mosquito control methods. Here, we analyzed cultivable bacteria isolated from all stages of the mosquito life cycle for their larvicidal activity against Ae. aegypti. A total of 424 bacterial strains isolated from eggs, larvae, pupae, or adult Ae. aegypti were analyzed for the pathogenic potential of their crude cultures against larvae of this same mosquito species. Nine strains displayed larvicidal activity comparable to the strain AM65-52, reisolated from commercial BTi-based product VectoBac® WG. 16S rRNA gene sequencing revealed that the set of larvicidal strains contains two representatives of the genus Bacillus, five Enterobacter, and two Stenotrophomonas. This study demonstrates that some bacteria isolated from Ae. aegypti are pathogenic for the mosquito from which they were isolated. The data are promising for developing novel bioinsecticides for the control of these medically important mosquitoes.
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Affiliation(s)
| | | | | | - Marta Rodrigues de Oliveira
- Department of Entomology and Acarology, Escola Superior de Agricultura "Luiz de Queiroz", University of São Paulo - ESALQ - USP, Brazil
| | - Elerson Matos Rocha
- School of Agricultural Sciences, Department of Bioprocesses and Biotechnology, Central Multiuser Laboratory, Universidade Estadual Paulista (UNESP), Botucatu, Brazil
| | | | - Edson Júnior do Carmo
- Programa de Pós-Graduação em Biotecnologia - PPGBIOTEC/UFAM, Brazil; Instituto de Ciências Biológicas - ICB/UFAM, Brazil
| | | | - Osvaldo Marinotti
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Olle Terenius
- Department of Cell and Molecular Biology, Uppsala University, P.O. Box 596, SE-751 24 Uppsala, Sweden.
| | - Spartaco Astolfi-Filho
- Programa de Pós-Graduação em Biotecnologia - PPGBIOTEC/UFAM, Brazil; Instituto de Ciências Biológicas - ICB/UFAM, Brazil
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Zhou G, Lee MC, Wang X, Zhong D, Githeko AK, Yan G. Mapping Potential Malaria Vector Larval Habitats for Larval Source Management in Western Kenya: Introduction to Multimodel Ensembling Approaches. Am J Trop Med Hyg 2024; 110:421-430. [PMID: 38350135 PMCID: PMC10919169 DOI: 10.4269/ajtmh.23-0108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 11/03/2023] [Indexed: 02/15/2024] Open
Abstract
Identification and mapping of larval sources are a prerequisite for effective planning and implementing mosquito larval source management (LSM). Ensemble modeling is increasingly used for prediction modeling, but it lacks standard procedures. We proposed a detailed framework to predict potential malaria vector larval habitats by using multimodel ensemble modeling, which includes selection of models, ensembling method, and predictors, evaluation of variable importance, prediction of potential larval habitats, and assessment of prediction uncertainty. The models were built and validated based on multisite, multiyear field observations and climatic/environmental variables. Model performance was tested using independent field observations. Overall, we found that the ensembled model predicted larval habitats with about 20% more accuracy than the average of the individual models ensembled. Key larval habitat predictors in western Kenya were elevation, geomorphon class, and precipitation for the 2 months prior. Additional predictors may be required to increase the predictive accuracy of the larva-positive habitats. This is the first study to provide a detailed framework for the process of multimodel ensemble modeling for malaria vector habitats. Mapping of potential habitats will be helpful in LSM planning.
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Affiliation(s)
- Guofa Zhou
- Program in Public Health, University of California, Irvine, California
| | - Ming-Chieh Lee
- Program in Public Health, University of California, Irvine, California
| | - Xiaoming Wang
- Program in Public Health, University of California, Irvine, California
| | - Daibin Zhong
- Program in Public Health, University of California, Irvine, California
| | - Andrew K. Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Guiyun Yan
- Program in Public Health, University of California, Irvine, California
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Tarimo FS, Dillip A, Kosia EM, Lwetoijera DW. Community perception of the autodissemination of pyriproxyfen for controlling malaria vectors in south-eastern Tanzania. Malar J 2023; 22:333. [PMID: 37924148 PMCID: PMC10625276 DOI: 10.1186/s12936-023-04773-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 10/26/2023] [Indexed: 11/06/2023] Open
Abstract
BACKGROUND The efficacy of the autodissemination of pyriproxyfen to control malaria vectors has been demonstrated under semi field environment in Tanzania. However, the information on how best communities should be engaged for its routine and large-scale adoption are lacking. This study assessed the community's level of knowledge, perceptions, acceptability of the autodissemination of pyriproxyfen, and the perceived risks on the safety of pyriproxyfen on the environment. METHODS This was a concurrent mixed methods study, comprised of a community-based survey of 400 household representatives and eight focus group discussions (FGDs). The study was conducted in two villages in Mlimba district in south-eastern Tanzania between June and August 2022. For the quantitative data analysis, descriptive statistics were applied using R software, while inductive approach was used for qualitative data analysis, using NVivo software. RESULTS Knowledge on autodissemination of pyriproxyfen approach was found to be relatively low among both the FGD respondents and surveyed community members (36%, n = 144). Nevertheless, when it was explained to them, the envisioned community support for the autodissemination approach was relatively high (97%, n = 388). One of the major perceived benefits of the autodissemination of pyriproxyfen was the reduction of malaria-transmitting mosquitoes and associated malaria transmission. Environmental impact of pyriproxyfen on non-target organisms and health risk to children were among the major concerns. When provided with information on the safety and its utilization particularly through autodissemination approach, 93.5% (n = 374) of the survey respondents said that they would allow the PPF-contaminated pots to be placed around their homes. Similarly, FGD respondents were receptive towards the autodissemination of pyriproxyfen, but emphasized on the need for raising awareness among community members before related field trials. CONCLUSION This study indicates a low knowledge but high support for scaling up of the autodissemination of pyriproxyfen as a complementary tool for malaria control in rural Tanzania. The Findings of this study suggest that community sensitization activities are required to improve the community's acceptability and trust of the approach before respective field trials.
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Affiliation(s)
- Felista S Tarimo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, United Republic of Tanzania.
- School of Life Sciences and Bio Engineering, The Nelson Mandela, African Institution of Science and Technology, P. O. Box 4447, Tengeru, Arusha, United Republic of Tanzania.
| | - Angel Dillip
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, United Republic of Tanzania
- School of Life Sciences and Bio Engineering, The Nelson Mandela, African Institution of Science and Technology, P. O. Box 4447, Tengeru, Arusha, United Republic of Tanzania
- Apotheker Health Access Initiative, P. O. Box 70022, Dar es Salaam, United Republic of Tanzania
| | - Efraim M Kosia
- School of Life Sciences and Bio Engineering, The Nelson Mandela, African Institution of Science and Technology, P. O. Box 4447, Tengeru, Arusha, United Republic of Tanzania
| | - Dickson W Lwetoijera
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, United Republic of Tanzania.
- School of Life Sciences and Bio Engineering, The Nelson Mandela, African Institution of Science and Technology, P. O. Box 4447, Tengeru, Arusha, United Republic of Tanzania.
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DeBoer KR, Vaz LM, Ondo Mfumu TA, Nlang JAM, Ondo L, Riloha Rivas M, Incardona S, Pollock J, von Fricken ME, Mba Eyono JN, Donfack OT, Guerra CA, García GA. Assessing IRS performance in a gender-integrated vector control programme on Bioko Island, Equatorial Guinea, 2010-2021. Malar J 2023; 22:323. [PMID: 37880774 PMCID: PMC10599007 DOI: 10.1186/s12936-023-04755-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 10/13/2023] [Indexed: 10/27/2023] Open
Abstract
BACKGROUND Indoor residual spraying (IRS) is a common vector control strategy in countries with high malaria burden. Historically, social norms have prevented women from working in IRS programmes. The Bioko Island Malaria Elimination Project has actively sought to reduce gender inequality in malaria control operations for many years by promoting women's participation in IRS. METHODS This study investigated the progress of female engagement and compared spray productivity by gender from 2010 to 2021, using inferential tests and multivariable regression. Spray productivity was measured by rooms sprayed by spray operator per day (RSOD), houses sprayed by spray operator per day (HSOD), and the daily productivity ratio (DPR), defined as the ratio of RSOD to HSOD, which standardized productivity by house size. RESULTS The percentage of women participating in IRS has increased over time. The difference in DPR comparing male and female spray operators was only statistically significant (p < 0.05) for two rounds, where the value was higher for women compared to men. Regression analyses showed marginal, significant differences in DPR between men and women, but beta coefficients were extremely small and thus not indicative of a measurable effect of gender on operational performance. CONCLUSIONS The quantitative analyses of spray productivity are counter to stigmatizing beliefs that women are less capable than male counterparts during IRS spray rounds. The findings from this research support the participation of women in IRS campaigns, and a renewed effort to implement equitable policies and practices that intentionally engage women in vector control activities.
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Affiliation(s)
| | | | - Teresa Ayingono Ondo Mfumu
- MCD Global Health, Malabo, Equatorial Guinea
- Ministry of Health and Social Welfare, National Malaria Control Programme, Malabo, Equatorial Guinea
| | | | - Lucas Ondo
- MCD Global Health, Malabo, Equatorial Guinea
| | - Matilde Riloha Rivas
- Ministry of Health and Social Welfare, National Malaria Control Programme, Malabo, Equatorial Guinea
| | | | | | - Michael E von Fricken
- Department of Environmental and Global Health, University of Florida, Gainesville, FL, USA
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Katak RDM, Cintra AM, Burini BC, Marinotti O, Souza-Neto JA, Rocha EM. Biotechnological Potential of Microorganisms for Mosquito Population Control and Reduction in Vector Competence. INSECTS 2023; 14:718. [PMID: 37754686 PMCID: PMC10532289 DOI: 10.3390/insects14090718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/11/2023] [Accepted: 08/19/2023] [Indexed: 09/28/2023]
Abstract
Mosquitoes transmit pathogens that cause human diseases such as malaria, dengue fever, chikungunya, yellow fever, Zika fever, and filariasis. Biotechnological approaches using microorganisms have a significant potential to control mosquito populations and reduce their vector competence, making them alternatives to synthetic insecticides. Ongoing research has identified many microorganisms that can be used effectively to control mosquito populations and disease transmission. However, the successful implementation of these newly proposed approaches requires a thorough understanding of the multipronged microorganism-mosquito-pathogen-environment interactions. Although much has been achieved in discovering new entomopathogenic microorganisms, antipathogen compounds, and their mechanisms of action, only a few have been turned into viable products for mosquito control. There is a discrepancy between the number of microorganisms with the potential for the development of new insecticides and/or antipathogen products and the actual available products, highlighting the need for investments in the intersection of basic research and biotechnology.
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Affiliation(s)
- Ricardo de Melo Katak
- Malaria and Dengue Laboratory, Instituto Nacional de Pesquisas da Amazônia-INPA, Manaus 69060-001, AM, Brazil;
| | - Amanda Montezano Cintra
- Multiuser Central Laboratory, Department of Bioprocesses and Biotechnology, School of Agricultural Sciences, São Paulo State University (UNESP), Botucatu 18610-034, SP, Brazil; (A.M.C.); (J.A.S.-N.)
| | - Bianca Correa Burini
- Florida Medical Entomology Laboratory, University of Florida, Vero Beach, FL 32962, USA;
| | - Osvaldo Marinotti
- Department of Biology, Indiana University, Bloomington, IN 47405, USA;
| | - Jayme A. Souza-Neto
- Multiuser Central Laboratory, Department of Bioprocesses and Biotechnology, School of Agricultural Sciences, São Paulo State University (UNESP), Botucatu 18610-034, SP, Brazil; (A.M.C.); (J.A.S.-N.)
| | - Elerson Matos Rocha
- Multiuser Central Laboratory, Department of Bioprocesses and Biotechnology, School of Agricultural Sciences, São Paulo State University (UNESP), Botucatu 18610-034, SP, Brazil; (A.M.C.); (J.A.S.-N.)
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Bacterial Toxins Active against Mosquitoes: Mode of Action and Resistance. Toxins (Basel) 2021; 13:toxins13080523. [PMID: 34437394 PMCID: PMC8402332 DOI: 10.3390/toxins13080523] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/18/2021] [Accepted: 06/19/2021] [Indexed: 12/25/2022] Open
Abstract
Larvicides based on the bacteria Bacillus thuringiensis svar. israelensis (Bti) and Lysinibacillus sphaericus are effective and environmentally safe compounds for the control of dipteran insects of medical importance. They produce crystals that display specific and potent insecticidal activity against larvae. Bti crystals are composed of multiple protoxins: three from the three-domain Cry type family, which bind to different cell receptors in the midgut, and one cytolytic (Cyt1Aa) protoxin that can insert itself into the cell membrane and act as surrogate receptor of the Cry toxins. Together, those toxins display a complex mode of action that shows a low risk of resistance selection. L. sphaericus crystals contain one major binary toxin that display an outstanding persistence in field conditions, which is superior to Bti. However, the action of the Bin toxin based on its interaction with a single receptor is vulnerable for resistance selection in insects. In this review we present the most recent data on the mode of action and synergism of these toxins, resistance issues, and examples of their use worldwide. Data reported in recent years improved our understanding of the mechanism of action of these toxins, showed that their combined use can enhance their activity and counteract resistance, and reinforced their relevance for mosquito control programs in the future years.
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Dambach P, Bärnighausen T, Yadouleton A, Dambach M, Traoré I, Korir P, Ouedraogo S, Nikiema M, Sauerborn R, Becker N, Louis VR. Is biological larviciding against malaria a starting point for integrated multi-disease control? Observations from a cluster randomized trial in rural Burkina Faso. PLoS One 2021; 16:e0253597. [PMID: 34143831 PMCID: PMC8213177 DOI: 10.1371/journal.pone.0253597] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 06/08/2021] [Indexed: 11/29/2022] Open
Abstract
Objectives To evaluate the impact of anti-malaria biological larviciding with Bacillus thuringiensis israelensis on non-primary target mosquito species in a rural African setting. Methods A total of 127 villages were distributed in three study arms, each with different larviciding options in public spaces: i) no treatment, ii) full or iii) guided intervention. Geographically close villages were grouped in clusters to avoid contamination between treated and untreated villages. Adult mosquitoes were captured in light traps inside and outside houses during the rainy seasons of a baseline and an intervention year. After enumeration, a negative binomial regression was used to determine the reductions achieved in the different mosquito species through larviciding. Results Malaria larviciding interventions showed only limited or no impact against Culex mosquitoes; by contrast, reductions of up to 34% were achieved against Aedes when all detected breeding sites were treated. Culex mosquitoes were captured in high abundance in semi-urban settings while more Aedes were found in rural villages. Conclusions Future malaria larviciding programs should consider expanding onto the breeding habitats of other disease vectors, such as Aedes and Culex and evaluate their potential impact. Since the major cost components of such interventions are labor and transport, other disease vectors could be targeted at little additional cost.
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Affiliation(s)
- Peter Dambach
- Institute for Global Health, University Hospital Heidelberg, Heidelberg, Germany
- * E-mail:
| | - Till Bärnighausen
- Institute for Global Health, University Hospital Heidelberg, Heidelberg, Germany
| | - Anges Yadouleton
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin
| | - Martin Dambach
- Institute of Zoology, University of Cologne, Cologne, Germany
| | - Issouf Traoré
- Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso
| | - Patricia Korir
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | | | | | - Rainer Sauerborn
- Institute for Global Health, University Hospital Heidelberg, Heidelberg, Germany
| | - Norbert Becker
- German Mosquito Control Association (KABS), Speyer, Germany
| | - Valérie R. Louis
- Institute for Global Health, University Hospital Heidelberg, Heidelberg, Germany
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Dambach P, Traoré I, Sawadogo H, Zabré P, Shukla S, Sauerborn R, Becker N, Phalkey R. Community acceptance of environmental larviciding against malaria with Bacillus thuringiensis israelensis in rural Burkina Faso - A knowledge, attitudes and practices study. Glob Health Action 2021; 14:1988279. [PMID: 34927578 PMCID: PMC8725727 DOI: 10.1080/16549716.2021.1988279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Background Malaria control is based on early treatment of cases and on vector control. The current measures for malaria vector control in Africa are mainly based on long-lasting insecticidal nets (LLINs) and to a much smaller extent on indoor residual spraying (IRS). While bed net use is widely distributed and its role is intensively researched, Bti-based larviciding is a relatively novel tool in Africa. In this study, we analyze the perception and acceptability of Bti-based larval source management under different larviciding scenarios that were performed in a health district in Burkina Faso. Objective To research people’s perception and acceptance regarding biological larviciding interventions against malaria in their communities. Methods A cross-sectional study was undertaken using a total of 634 administered questionnaires. Data were collected in a total of 36 rural villages and in seven town quarters of the semi-urban town of Nouna. Results Respondents had basic to good knowledge regarding malaria transmission and how to protect oneself against it. More than 90% reported sleeping under a bed net, while other measures such as mosquito coils and insecticides were only used by a minority. The majority of community members reported high perceived reductions in mosquito abundance and the number of malaria episodes. There was a high willingness to contribute financially to larviciding interventions among interviewees. Conclusions This study showed that biological larviciding interventions are welcomed by the population that they are regarded as an effective and safe means to reduce mosquito abundance and malaria transmission. A routine implementation would, despite low intervention costs, require community ownership and contribution.
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Affiliation(s)
- Peter Dambach
- Heidelberg Institute of Global Health, University of Heidelberg, Heidelberg, Germany
| | - Issouf Traoré
- Centre De Recherche En Santé De Nouna, Nouna, Burkina Faso.,Institut De Formations Initiale Et Continue, Université Thomas Sankara, Ouagadougou, Burkina Faso
| | | | - Pascal Zabré
- Centre De Recherche En Santé De Nouna, Nouna, Burkina Faso
| | - Sharvari Shukla
- Symbiosis Statistical Institute, Symbiosis International (Deemed University)
| | - Rainer Sauerborn
- Heidelberg Institute of Global Health, University of Heidelberg, Heidelberg, Germany
| | - Norbert Becker
- German Mosquito Control Association (KABS), Speyer, Germany.,Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Revati Phalkey
- Heidelberg Institute of Global Health, University of Heidelberg, Heidelberg, Germany.,Epidemiology and Public Health Division, University of Nottingham, Nottingham, UK.,Climate Change and Health Group, Public Health England, Chilton, UK
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