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Jafari Y, Brady OJ, Briggs JR, Lien LT, Mai HK, Nguyen HAT, Van Loock M, Herrera-Taracena G, Menten J, Iwasaki C, Takegata M, Kitamura N, Do Thai H, Minh BX, Morita K, Anh DD, Clifford S, Prem K, Hafalla J, Edmunds WJ, Yoshida LM, Hibberd ML, Hué S. Could prophylactic antivirals reduce dengue incidence in a high-prevalence endemic area? PLoS Negl Trop Dis 2024; 18:e0012334. [PMID: 39074158 DOI: 10.1371/journal.pntd.0012334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 06/29/2024] [Indexed: 07/31/2024] Open
Abstract
Prophylactic drugs against dengue are currently under development. In this study, we explored how such prophylactic approaches might affect dengue cases in four communes of Nha Trang City, Vietnam. A community level dengue transmission survey indicated high levels of previous exposure to dengue (89.7%; 95% CI: 87.2,92.0). We fitted a spatially explicit model to an observed outbreak and simulated likely effectiveness of Case-Area Targeted Interventions (CATI) and One-Time Mass Distribution (OTMD) of drug and vector control strategies. Increasing the radius and effectiveness and decreasing delay of CATI was most effective, with drugs being more effective in averting dengue cases than vector control. Using an OTMD approach early in the outbreak required the least number of treatments to avert a case, suggesting that OTMD strategies should be considered as pre-emptive rather than reactive strategies. These findings show that pre-emptive interventions can substantially reduce the burden of dengue outbreaks in endemic settings.
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Affiliation(s)
- Yalda Jafari
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Public Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Oliver J Brady
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Public Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Joseph R Briggs
- Department of Infection Biology, Faculty of Infectious Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Le Thuy Lien
- Pasteur Institute in Nha Trang, Nha Trang, Vietnam
| | | | | | - Marnix Van Loock
- Janssen Research & Development, Janssen Pharmaceutica NV, Janssen Pharmaceutical Companies of Johnson & Johnson, Beerse, Belgium
| | - Guillermo Herrera-Taracena
- Janssen Research & Development, Janssen Pharmaceutica NV, Janssen Pharmaceutical Companies of Johnson & Johnson, Beerse, Belgium
| | - Joris Menten
- Janssen Research & Development, Janssen Pharmaceutica NV, Janssen Pharmaceutical Companies of Johnson & Johnson, Beerse, Belgium
| | - Chihiro Iwasaki
- Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Mizuki Takegata
- Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Noriko Kitamura
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Public Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Hung Do Thai
- Pasteur Institute in Nha Trang, Nha Trang, Vietnam
| | - Bui Xuan Minh
- Khanh Hoa health Service Department, Nha Trang, Vietnam
| | - Kouichi Morita
- Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Dang Duc Anh
- National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
| | - Sam Clifford
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Public Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Kiesha Prem
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Public Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Julius Hafalla
- National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
| | - W John Edmunds
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Public Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Lay Myint Yoshida
- Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | | | - Stéphane Hué
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Public Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
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da Silva AS, de Mello TF, Fagá HFE, Knorst JK, Silva FRMB, Leite GAA. Female Mice Exposed to Pyriproxyfen Since Prepuberty Showed Reproductive Impairment During Sexual Maturity and Increased Fetal Death in Their Offspring. ENVIRONMENTAL TOXICOLOGY 2024. [PMID: 39037111 DOI: 10.1002/tox.24374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 02/26/2024] [Accepted: 06/01/2024] [Indexed: 07/23/2024]
Abstract
Pyriproxyfen (PPF) is an insecticide used in agriculture, which is approved for use in drinking water tanks for human consumption. However, some studies indicate that it may act as an endocrine disruptor and affect nontarget organisms. This study aimed to evaluate the effects of PPF on reproduction and general health status in female mice exposed from pre-puberty to adulthood. In the first experiment, females were treated by gavage from postnatal day (PND) 23 to (PND) 75 and were distributed into three experimental groups: control (vehicle), PPF 0.1 mg/kg, and PPF 1 mg/kg. Female mice were assessed for the age of puberty onset, body mass, water and food consumption, and the estrous cycle. On PDN 75, a subgroup was euthanized, when vital and reproductive organs were collected and weighed. The thyroid, ovary, and uterus were evaluated for histomorphometry. The other subgroup was assessed in relation to reproductive performance and fetal parameters. In a second experiment, the uterotrophic assay was performed with juvenile females (PND 18) using doses of 0.01, 0.1, or 1 mg/kg of PPF. PPF treatment reduced thyroid mass and increased liver mass. Furthermore, there was an increase in ovarian interstitial tissue and, in the uterus, a decrease in the thickness of the endometrial stroma with reduced content of collagen fibers. There was also a reduction of 30% in pregnancy rate in the treated groups and an increase in the frequency of fetal death. This study suggests that, based on this experimental model, the insecticide may pose a reproductive risk for females chronically exposed to the substance from the pre-pubertal period until adulthood. These results raise concerns about prolonged exposure of women to the same compound.
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Affiliation(s)
- Alice Santos da Silva
- Laboratório de Reprodução e Toxicologia (Laretox), Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
- Programa de Pós-graduação em Biologia Celular e Do Desenvolvimento, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Tainara Fernandes de Mello
- Laboratório de Reprodução e Toxicologia (Laretox), Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
- Programa de Pós-graduação em Biologia Celular e Do Desenvolvimento, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Henrique Frederico Enz Fagá
- Laboratório de Reprodução e Toxicologia (Laretox), Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Jennyfer Karen Knorst
- Laboratório de Reprodução e Toxicologia (Laretox), Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | | | - Gabriel Adan Araújo Leite
- Laboratório de Reprodução e Toxicologia (Laretox), Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
- Departamento de Biologia Celular, Embriologia e Genética, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
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3
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Salesa B, Torres-Gavilá J, Ferrando-Rodrigo MD, Sancho E. Pyriproxyfen Contamination in Daphnia magna: Identifying Early Warning Biomarkers. J Xenobiot 2024; 14:214-226. [PMID: 38390993 PMCID: PMC10885111 DOI: 10.3390/jox14010013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 01/29/2024] [Accepted: 01/31/2024] [Indexed: 02/24/2024] Open
Abstract
Pyriproxyfen is an insecticide currently employed in numerous countries for the management of agricultural and indoor pests. Several studies indicate that this insecticide has been detected in multiple rivers, with concentrations reaching as high as 99.59 ng/L in the Júcar River in Spain. Therefore, the determination of some biochemical and genetic effects of this insecticide on aquatic organisms could serve as an early warning mechanism to identify potential disruptions in various biomarkers. Based on this, Daphnia magna organisms were exposed to pyriproxyfen sublethal concentrations for 21 days. Some biochemical parameters, including cholesterol, triglycerides, glucose, lactate, and LDH activity, were determined. Additionally, some genetic biomarkers associated with oxidative stress, heat shock proteins, lipid metabolism, hemoglobin, metallothioneins, and vitellogenin synthesis were evaluated in daphnids exposed to the insecticide for 21 days. LDH activity increased significantly in those daphnids exposed to the highest insecticide concentration (14.02 µg/L), while cholesterol levels decreased significantly. In contrast, glucose, total proteins, and triglycerides remained unaffected in D. magna exposed to pyriproxyfen. On the other hand, exposure to the insecticide led to notable alterations in gene expression among individuals. Specifically, genes associated with lipid metabolism and reproduction exhibited a significant reduction in gene expression. Fabd expression was decreased by approximately 20% in exposed daphnids, while vtg expression was suppressed as much as 80% when compared to control values. Furthermore, it was observed that the hgb1 and hgb2 genes, associated with hemoglobin synthesis, exhibited significant overexpression. Notably, the dysfunction observed in both hemoglobin genes was linked to an increase in pigmentation in Daphnia magna during the course of the experiment. These alterations in gene expression could serve as effective indicators of early contamination even at low pesticide concentrations.
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Affiliation(s)
- Beatriz Salesa
- Biomaterials and Bioengineering Lab, Centro de Investigación Traslacional San Alberto Magno, Universidad Católica de Valencia San Vicente Mártir, 46001 Valencia, Spain
| | - Javier Torres-Gavilá
- Instituto de Investigación en Medio Ambiente y Ciencia Marina (IMEDMAR-UCV), c/Guillem de Castro 94, 46001 Valencia, Spain
| | - María Dolores Ferrando-Rodrigo
- Laboratory of Ecotoxicology, Functional Biology and Physical Anthropology Department, Faculty of Biology, University of Valencia, Dr. Moliner 50, 46100 Valencia, Spain
| | - Encarnación Sancho
- Laboratory of Ecotoxicology, Functional Biology and Physical Anthropology Department, Faculty of Biology, University of Valencia, Dr. Moliner 50, 46100 Valencia, Spain
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Mmbaga AT, Lwetoijera DW. Current and future opportunities of autodissemination of pyriproxyfen approach for malaria vector control in urban and rural Africa. Wellcome Open Res 2023; 8:119. [PMID: 37440995 PMCID: PMC10333782 DOI: 10.12688/wellcomeopenres.19131.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/23/2023] [Indexed: 07/15/2023] Open
Abstract
Despite the progress made in reducing malaria burden, new ways to address the increasing challenges of insecticide resistance and the invasion and spread of exotic malaria vectors such as Anopheles stephensi in Africa are urgently needed. While African countries are adopting larviciding as a complementary intervention for malaria vector control, the autodissemination technology has the potential to overcome barriers associated with the identification and treatment of prolific habitats that impede conventional larviciding approaches in rural settings. The autodissemination technology as a "lure and release" strategy works by exploiting the resting behavior of gravid mosquitoes to transfer lethal concentration of biological or chemical insecticide such as pyriproxyfen (PPF), an insect growth regulator (IGRs) to their oviposition sites and result in adult emergence inhibition. Despite the evidence of the autodissemination approach to control other mosquito-borne diseases, there is growing and promising evidence for its use in controlling malaria vectors in Africa, which highlights the momentous research that needs to be sustained. This article reviews the evidence for efficacy of the autodissemination approach using PPF and discusses its potential as efficient and affordable complementary malaria vector control intervention in Africa. In the previous studies that were done in controlled semi-field environments, autodissemination with PPF demonstrated its potential in reducing densities of captive population of malaria vectors such as Anopheles gambiae and Anopheles arabiensis. Of importance, empirical evidence and biology-informed mathematical models to demonstrate the utility of the autodissemination approach to control wild populations of malaria vectors under field environment either alone or in combination with other tools are underway. Among others, the key determining factors for future introduction of this approach at scale is having scalable autodissemination devices, optimized PPF formulations, assess its integration/complementarity to existing conventional larviciding, and community perception and acceptance of the autodissemination approach.
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Affiliation(s)
- Augustino Thabiti Mmbaga
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Ifakara, Morogoro, P.O. Box 53, Tanzania
| | - Dickson Wilson Lwetoijera
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Ifakara, Morogoro, P.O. Box 53, Tanzania
- School of Life Sciences and Bio Engineering, Nelson Mandela African Institution of Science and Technology, Tengeru, Arusha, P.O. Box 447, Tanzania
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Salesa B, Torres-Gavilá J, Sancho E, Ferrando MD. Multigenerational effects of the insecticide Pyriproxyfen and recovery in Daphnia magna. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 886:164013. [PMID: 37164084 DOI: 10.1016/j.scitotenv.2023.164013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 04/27/2023] [Accepted: 05/04/2023] [Indexed: 05/12/2023]
Abstract
In the present study, an ecotoxicological approach to the evaluation of the insecticide Pyriproxifen in the crustacean Daphnia magna was done. Acute toxicity tests (48 h), feeding behavior test (5 h) and chronic toxicity test (21 days) were carried out on a parental daphnid generation (F0). Pyriproxifen D. magna EC50 value in our experimental conditions was 336.47 μg/L. Based on this result, sublethal test concentrations were selected for the feeding study and the F0 chronic experiment. Filtration and ingestion rates of D. magna exposed animals did not show any significant difference respect to control daphnids. However, daphnids from the parental F0 generation when exposed to the insecticide during 21 days showed a decreased in all the reproductive parameters tested (mean total neonates per female, mean brood size, time to first brood, and mean number of broods per female) as well as in the population statistic growth rate (r), although survival was not affected. On the other hand, offspring from F0 females exposed to the highest Pyriproxifen concentration (14.02 μg/L) were separated in two F1 generation experiments. One group was transferred during 21 days to a medium free of toxicant (F1 generation-TC group) while the other group was exposed during 21 days to the same insecticide concentration as their mothers (14.02 μg/L) (F1 generation-TT group). Results from both experiments determined a decreased in most of the reproductive parameters which was higher in the F1-TT group, although some of them were recovered in the F1-TC group. On the other hand, the morphological analysis of the daphnids showed that the coloration pattern was altered in the daphnids exposed to the insecticide, together with a significant size decreased, and neonates from F0 progeny with the same morphological abnormality. Finally, we determined that the insecticide caused the appearance of males among the offspring generated by the F0.
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Affiliation(s)
- Beatriz Salesa
- Biomaterials and Bioengineering Lab, Centro de Investigación Traslacional San Alberto Magno, Universidad Católica de Valencia San Vicente Mártir, c/Guillem de Castro 94, 46001, Valencia, Spain.
| | - Javier Torres-Gavilá
- Instituto de Investigación en Medio Ambiente y Ciencia Marina (IMEDMAR-UCV), c/Guillem de Castro 94, 46001, Valencia, Spain
| | - Encarnación Sancho
- Laboratory of Ecotoxicology, Dept. Functional Biology and Physical Anthropology, Faculty of Biology, University of Valencia, Dr. Moliner 50, E-46100 Burjassot, Valencia, Spain
| | - María Dolores Ferrando
- Laboratory of Ecotoxicology, Dept. Functional Biology and Physical Anthropology, Faculty of Biology, University of Valencia, Dr. Moliner 50, E-46100 Burjassot, Valencia, Spain
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Campos KB, Alomar AA, Eastmond BH, Obara MT, S Dias LD, Rahman RU, Alto BW. Assessment of insecticide resistance of Aedes aegypti (Diptera: Culicidae) populations to insect growth regulator pyriproxyfen, in the northeast region of Brazil. JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2023; 48:12-18. [PMID: 37255355 DOI: 10.52707/1081-1710-48.1.12] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 11/21/2022] [Indexed: 06/01/2023]
Abstract
Vector control has been an essential strategy in Brazil to manage vector-borne diseases, and the use of insecticides plays an important role in this effort. Pyriproxyfen (PPF) has become a common insect growth regulator used to control juvenile stages of mosquitoes by disturbing their growth and development. This study assesses the susceptibility and resistance status of Brazilian Ae. aegypti populations that previously showed low resistance levels to PPF. Eggs of Ae. aegypti were collected from six cities located in the northeast states of Ceará (Quixadá, Icó, and Juazeiro do Norte), and Bahia (Itabuna, Brumado, and Serrinha). We used the Ae. aegypti Rockefeller strain as an experimental control and a strain known to be susceptible to insecticides. Inhibition of emergence rates by 50% of Ae. aegypti populations varied from 0.0098-0.046 µg/L. Mosquitoes from Icó, Serrinha, and Brumado showed low resistance levels [resistance ratio (RR50) = 2.33, 4.52, and 4.83, respectively], whereas moderate levels of resistance were detected in populations from Juazeiro do Norte (RR50=5.83) and Itabuna (RR50=7.88). Aedes aegypti collected from the Quixadá population showed a high resistance level to pyriproxyfen (RR50=11). The evolution of resistance in Brazilian Ae. aegypti populations to PPF can compromise vector control efforts. Continuous monitoring of insecticide resistance in Ae. aegypti is essential for making timely management decisions for effective vector control and management.
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Affiliation(s)
- Kauara B Campos
- Entomology and Nematology Department, Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, FL 32962, USA
- Laboratório de Parasitologia Médica e Biologia de Vetores, Faculdade de Medicina, Universidade de Brasília, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília/Distrito Federal CEP 70910-900, Brazil
- Coordenação Geral de Vigilância de Aboviroses, Secretaria de Vigilância em Saúde, Ministério da Saúde, Brasília/ Distrito Federal CEP 70723-040, Brazil
- Laboratório de Fisiologia e Controle de Artrópodes Vetores, Instituto Oswaldo Cruz, Bairro Benfica, Rio de Janeiro/Rio de Janeiro State CEP 20911-270, Brazil
| | - Abdullah A Alomar
- Entomology and Nematology Department, Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, FL 32962, USA
| | - Bradley H Eastmond
- Entomology and Nematology Department, Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, FL 32962, USA
| | - Marcos T Obara
- Laboratório de Parasitologia Médica e Biologia de Vetores, Faculdade de Medicina, Universidade de Brasília, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília/Distrito Federal CEP 70910-900, Brazil
| | - Luciana Dos S Dias
- Laboratório de Fisiologia e Controle de Artrópodes Vetores, Instituto Oswaldo Cruz, Bairro Benfica, Rio de Janeiro/Rio de Janeiro State CEP 20911-270, Brazil
| | - Rafi U Rahman
- Laboratório de Fisiologia e Controle de Artrópodes Vetores, Instituto Oswaldo Cruz, Bairro Benfica, Rio de Janeiro/Rio de Janeiro State CEP 20911-270, Brazil
| | - Barry W Alto
- Entomology and Nematology Department, Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, FL 32962, USA,
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7
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Mmbaga AT, Lwetoijera DW. Current and future opportunities of autodissemination of pyriproxyfen approach for malaria vector control in urban and rural Africa. Wellcome Open Res 2023. [DOI: 10.12688/wellcomeopenres.19131.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023] Open
Abstract
Despite the progress made in reducing malaria burden, new ways to address the increasing challenges of insecticide resistance and the invasion and spread of exotic malaria vectors such as Anopheles stephensi in Africa are urgently needed. While African countries are adopting larviciding as a complementary intervention for malaria vector control, the autodissemination technology has the potential to overcome barriers associated with the identification and treatment of prolific habitats that impede conventional larviciding approaches in rural settings. The autodissemination technology as a “lure and release” strategy works by exploiting the resting behavior of gravid mosquitoes to transfer lethal concentration of biological or chemical insecticide such as pyriproxyfen (PPF), an insect growth regulator (IGRs) to their oviposition sites and result in adult emergence. Despite the evidence of the autodissemination approach to control other mosquito-borne diseases, there is growing and promising evidence for its use in controlling malaria vectors in Africa, which highlights the momentous research that needs to be sustained. This article reviews the evidence for efficacy of the autodissemination approach using PPF and discusses its potential as efficient and affordable complementary malaria vector control intervention in Africa. In the previous studies that were done in controlled semi-field environments, autodissemination with PPF demonstrated its potential in reducing densities of captive population of malaria vectors such as Anopheles gambiae and Anopheles arabiensis. Of importance, empirical evidence and biology-informed mathematical models to demonstrate the utility of the autodissemination approach to control wild populations of malaria vectors under field environment either alone or in combination with other tools are underway. Among others, the key determining factors for future introduction of this approach at scale is having scalable autodissemination devices, optimized PPF formulations, assess its integration/complementarity to existing conventional larviciding, and community perception and acceptance of the autodissemination approach.
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Jaffal A, Fite J, Baldet T, Delaunay P, Jourdain F, Mora-Castillo R, Olive MM, Roiz D. Current evidences of the efficacy of mosquito mass-trapping interventions to reduce Aedes aegypti and Aedes albopictus populations and Aedes-borne virus transmission. PLoS Negl Trop Dis 2023; 17:e0011153. [PMID: 36877728 PMCID: PMC10032496 DOI: 10.1371/journal.pntd.0011153] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/22/2023] [Accepted: 02/08/2023] [Indexed: 03/07/2023] Open
Abstract
BACKGROUND Over the past decades, several viral diseases transmitted by Aedes mosquitoes-dengue, chikungunya, Zika-have spread outside of tropical areas. To limit the transmission of these viruses and preserve human health, the use of mosquito traps has been developed as a complement or alternative to other vector control techniques. The objective of this work was to perform a systematic review of the existing scientific literature to assess the efficacy of interventions based on adult mosquito trap to control Aedes population densities and the diseases they transmit worldwide. METHODS AND FINDINGS Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic review was conducted using the PubMed and Scopus databases. Among the 19 selected papers, lethal ovitraps were used in 16 studies, host-seeking female traps in 3 studies. Furthermore, 16 studies focused on the control of Ae. aegypti. Our review showed great heterogeneity in the indicators used to assess trap efficacy: e.g., the number of host-seeking females, the number of gravid females, the proportion of positive containers, the viral infection rate in female mosquitoes or serological studies in residents. Regardless of the type of studied traps, the results of various studies support the efficacy of mass trapping in combination with classical integrated vector control in reducing Aedes density. More studies with standardized methodology, and indicators are urgently needed to provide more accurate estimates of their efficacy. CONCLUSIONS This review highlights gaps in the demonstration of the efficacy of mass trapping of mosquitoes in reducing viral transmission and disease. Thus, further large-scale cluster randomized controlled trials conducted in endemic areas and including epidemiological outcomes are needed to establish scientific evidence for the reduction of viral transmission risk by mass trapping targeting gravid and/or host-seeking female mosquitoes.
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Affiliation(s)
- Ali Jaffal
- French Agency for Food, Environmental and Occupational Health & Safety (Anses), Maisons-Alfort, France
| | - Johanna Fite
- French Agency for Food, Environmental and Occupational Health & Safety (Anses), Maisons-Alfort, France
| | - Thierry Baldet
- ASTRE (Animal, Santé, Territoires, Risques, Ecosystèmes), CIRAD, Univ Montpellier, Montpellier, France
| | - Pascal Delaunay
- Service de Parasitologie-Mycologie, Hôpital L'Archet, Centre Hospitalier Universitaire de Nice, UCA, Nice, France
| | - Frédéric Jourdain
- Santé publique France (French National Public Health Agency), Montpellier, France
- MIVEGEC, IRD, CNRS, Université Montpellier, Montpellier, France
| | | | - Marie-Marie Olive
- ASTRE (Animal, Santé, Territoires, Risques, Ecosystèmes), CIRAD, Univ Montpellier, Montpellier, France
- MIVEGEC, IRD, CNRS, Université Montpellier, Montpellier, France
| | - David Roiz
- MIVEGEC, IRD, CNRS, Université Montpellier, Montpellier, France
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Ligsay AD, Regencia ZJG, Tambio KJM, Aytona MJM, Generale AJA, Alejandro GJD, Tychuaco JS, De las Llagas LA, Baja ES, Paul REL. Efficacy Assessment of Autodissemination Using Pyriproxyfen-Treated Ovitraps in the Reduction of Dengue Incidence in Parañaque City, Philippines: A Spatial Analysis. Trop Med Infect Dis 2023; 8:66. [PMID: 36668973 PMCID: PMC9864649 DOI: 10.3390/tropicalmed8010066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/06/2023] [Accepted: 01/11/2023] [Indexed: 01/18/2023] Open
Abstract
Dengue is one of the most important vector-borne diseases worldwide and is a significant public health problem in the tropics. Mosquito control continues to be the primary approach to reducing the disease burden and spread of dengue virus (DENV). Aside from the traditional larviciding and adulticiding interventions, autodissemination using pyriproxyfen-treated (AD-PPF) ovitraps is one of the promising methods to complement existing vector control strategies. Our paper assessed the efficacy of AD-PPF in reducing DENV infections in two barangays in Parañaque City. Using saliva samples from the participants from both the control and intervention sites, we collected the seroprevalence data for three months in each of the two years. Spatial analysis was conducted to determine hotspot areas and identify DENV infection distributions across the trial periods. The results showed that the intervention site was identified as having a clustering of DENV infections in Month 0 of Year 1 and shifted to a random dispersion of dengue cases at the end of Month 3 in Year 2. The disappearance of the clustering of the intervention site translates to a decrease in the cases of DENV infection relative to the control site. Furthermore, we also identified that DENV transmission occurred at a small-scale level that did not go beyond 86 m. In conclusion, AD-PPF is suggested to be an effective strategy and may be used as an additional vector control approach, albeit based on this short-term implementation.
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Affiliation(s)
- Antonio D. Ligsay
- The Graduate School, University of Santo Tomas España Blvd., Manila 1008, Philippines
- Clinical Research Section, St. Luke’s College of Medicine—William H. Quasha Memorial, 279 E. Rodriguez Sr. Ave, Quezon City 1112, Philippines
- Department of Biological Sciences, College of Science, University of Santo Tomas España Blvd., Manila 1008, Philippines
| | - Zypher Jude G. Regencia
- Institute of Clinical Epidemiology, National Institutes of Health, University of the Philippines Manila, 623 Pedro Gil St., Ermita, Manila 1000, Philippines
- Department of Clinical Epidemiology, College of Medicine, University of the Philippines Manila, Pedro Gil Street, Taft Ave, Ermita, Manila 1000, Philippines
| | - Kristan Jela M. Tambio
- Clinical Research Section, St. Luke’s College of Medicine—William H. Quasha Memorial, 279 E. Rodriguez Sr. Ave, Quezon City 1112, Philippines
| | - Michelle Joyce M. Aytona
- Clinical Research Section, St. Luke’s College of Medicine—William H. Quasha Memorial, 279 E. Rodriguez Sr. Ave, Quezon City 1112, Philippines
| | - Alain Jason A. Generale
- Clinical Research Section, St. Luke’s College of Medicine—William H. Quasha Memorial, 279 E. Rodriguez Sr. Ave, Quezon City 1112, Philippines
| | - Grecebio Jonathan D. Alejandro
- The Graduate School, University of Santo Tomas España Blvd., Manila 1008, Philippines
- Department of Biological Sciences, College of Science, University of Santo Tomas España Blvd., Manila 1008, Philippines
| | - Jacquiline S. Tychuaco
- The Graduate School, University of Santo Tomas España Blvd., Manila 1008, Philippines
- Department of Biology, College of Science, Polytechnic University of the Philippines, Anonas St., Santa Mesa, Manila 1016, Philippines
| | - Lilian A. De las Llagas
- Department of Parasitology, College of Public Health, University of the Philippines Manila 625 Pedro Gil St., Ermita, Manila 1000, Philippines
| | - Emmanuel S. Baja
- Institute of Clinical Epidemiology, National Institutes of Health, University of the Philippines Manila, 623 Pedro Gil St., Ermita, Manila 1000, Philippines
- Department of Clinical Epidemiology, College of Medicine, University of the Philippines Manila, Pedro Gil Street, Taft Ave, Ermita, Manila 1000, Philippines
| | - Richard Edward L. Paul
- Institut Pasteur, Université de Paris, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 2000, Ecology and Emergence of Arthropod-Borne Pathogens Unit, 75015 Paris, France
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10
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Kala S, Jawle CKD, Singh MK, Sogan N, Singh H, Shukla G, Agarwal A, Takhur LK, Kumar J. Pomegranate Resembling Design of Starch Sago Beads Encapsulates Nanopyriproxyfen, Enabling Slow Release and Improved Bioactivity. ACS APPLIED MATERIALS & INTERFACES 2023; 15:1843-1858. [PMID: 36539955 DOI: 10.1021/acsami.2c18003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Environmental contamination by intense insecticide usage is consistently proposed as a significant contributor to major hazards; further, disturbing non-target populations provoke a grave concern worldwide as they play essential roles in ecosystems. Pyriproxyfen is one of the most widely used pesticides; however, due to its probable toxicity, its global application in large amounts may result in water concentrations that exceed regulatory pollution thresholds. Herein, we describe nanopyriproxyfen-loaded sago beads (PPX-NCB) designed for the slow release of pyriproxyfen (PPX). Our design is inspired by the composite structure of sago beads, composed of several small beads resembling a pomegranate. The microscopic beads accumulate chitosan-PPX-nanomicelles cross-linked with tripolyphosphate via physical absorption, offering adequate room for water absorption and subsequent PPX release. PPX-NCB had distinct effects on the immature egg and larva of Anopheles stephensi, limiting embryonic development in the eggs while enhancing bioactivity. It affects the integument of larvae and alters the surface hydrocarbons of eggs and larvae. In addition, PPX-NCB demonstrates an improved safety profile in non-target Daphnia magna.
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Affiliation(s)
- Smriti Kala
- Institute of Pesticide Formulation Technology (IPFT), Gurugram122016, Haryana, India
| | - Chetan K D Jawle
- Institute of Pesticide Formulation Technology (IPFT), Gurugram122016, Haryana, India
| | - Mukesh Kumar Singh
- Institute of Pesticide Formulation Technology (IPFT), Gurugram122016, Haryana, India
| | - Nisha Sogan
- Department of Botany, Deshbandhu College, University of Delhi, New Delhi110019, India
| | - Himmat Singh
- National Institute of Malaria Research (NIMR), Delhi110077, India
| | - Gaurav Shukla
- Department of Statistics and Computer Science, Banda University of Agriculture & Technology (BUAT), Banda210001, India
| | - Amrish Agarwal
- Institute of Pesticide Formulation Technology (IPFT), Gurugram122016, Haryana, India
| | - L K Takhur
- Institute of Pesticide Formulation Technology (IPFT), Gurugram122016, Haryana, India
| | - Jitendra Kumar
- Institute of Pesticide Formulation Technology (IPFT), Gurugram122016, Haryana, India
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11
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Valbon W, Araújo SHC, Nery RS, Barbosa JF, Newland PL, Oliveira EE. Sublethal exposure to pyriproxyfen does not impair the abilities of the backswimmer Buenoa amnigenus to prey upon Aedes aegypti larvae. ECOTOXICOLOGY (LONDON, ENGLAND) 2022; 31:998-1008. [PMID: 35779162 DOI: 10.1007/s10646-022-02562-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/20/2022] [Indexed: 06/15/2023]
Abstract
Pyriproxyfen is a juvenile hormone analogue that is commonly used to control the immature stages of mosquitoes in both artificial and natural water reservoirs. Recently, concerns have been raised regarding the community effectiveness of pyriproxyfen in preventing vector-transmitted diseases. Such concerns have been based on the unintended effects on non-target organisms and the selection of resistant mosquito populations. This investigation was, therefore, conducted to evaluate the toxicity of pyriproxyfen to Aedes aegypti (Diptera: Culicidae) larvae and the backswimmer Buenoa amnigenus (Hemiptera: Notonectidae), a naturally occurring mosquito larvae predator. We also assessed the abilities of backswimmers exposed to sublethal levels of pyriproxyfen to prey upon mosquito larvae (L2) under three larval densities (3, 6, or 9 larvae/100 mL of water) using artificial containers. Our results revealed that pyriproxyfen killed backswimmers only at concentrations higher than 100 μg active ingredient [a.i.]/L, which is 10 times higher than that recommended for larvicidal field application (i.e, 10 μg a.i./L). The abilities of backswimmers exposed to sublethal levels of pyriproxyfen (100 μg a.i./L) to prey upon mosquito larvae were not affected. Harmful effects on the backswimmer predatory abilities were detected only at concentrations of 150 μg a.i./L and when there was a higher prey availability (i.e., 9 larvae/100 mL of water). Together, our findings indicate that the reduced community effectiveness of this insecticide derives from factors other than its detrimental effects on non-target organisms such as backswimmers.
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Affiliation(s)
- Wilson Valbon
- Department of Entomology, Universidade Federal de Viçosa, Viçosa, MG, Brazil.
- Department of Biology, Duke University, Durham, NC, USA.
| | | | - Ritanne S Nery
- Department of Entomology, Universidade Federal de Viçosa, Viçosa, MG, Brazil
- Institute of Biological Sciences, Universidade Federal de Goiás, Goiânia, GO, Brazil
| | - Julianna F Barbosa
- Department of Zoology, Institute of Biology, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Philip L Newland
- School of Biological Sciences, University of Southampton, Highfield Campus, Southampton, United Kingdom
| | - Eugênio E Oliveira
- Department of Entomology, Universidade Federal de Viçosa, Viçosa, MG, Brazil.
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12
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Patel SS, Rauscher M, Kudela M, Pang H. Clinical Safety Experience of TAK-003 for Dengue Fever: A New Tetravalent Live Attenuated Vaccine Candidate. Clin Infect Dis 2022; 76:e1350-e1359. [PMID: 35639602 PMCID: PMC9907483 DOI: 10.1093/cid/ciac418] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 05/12/2022] [Accepted: 05/20/2022] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND An unmet medical need remains for an effective dengue tetravalent vaccine that can be administered irrespective of previous dengue exposure. TAK-003, a dengue tetravalent vaccine, has demonstrated efficacy in an ongoing phase 3 trial in children and adolescents living in dengue-endemic areas, with an acceptable safety profile in both dengue-naive and dengue-exposed individuals. METHODS Safety findings are presented herein from an integrated analysis of data for healthy 4-60-year-olds from two phase 2 and three phase 3 double-blind, placebo-controlled clinical trials of TAK-003 (TAK-003, n = 14 627; placebo, n = 7167). Safety evaluation included analyses of postinjection reactogenicity, unsolicited adverse events (AEs), serious AEs (SAEs), and deaths. Subgroup analyses were performed by age group, baseline serostatus, and gender. RESULTS The most common local and systemic AEs were injection site pain (43% for TAK-003 and 26% for placebo) and headache (34% and 30%, respectively). Injection site AEs were mostly mild and resolved within 1-3 days. Unsolicited AEs and AEs leading to discontinuation occurred with similar frequency across both groups, while SAEs were fewer for TAK-003 recipients (6% vs 8% for placebo). Four of the 5 vaccine-related SAEs (which included hypersensitivity, dengue fever, and dengue hemorrhagic fever) occurred in the placebo group. No deaths were considered vaccine-related. Subgroup analyses showed no differences in safety by baseline serostatus or by gender, albeit analysis by age indicated greater local reactogenicity rates for adolescents (46% for TAK-003 and 28% for placebo) and adults (56% and 19%, respectively) than for children (37% and 25%, respectively). CONCLUSIONS No important safety risks were identified, and TAK-003 was well tolerated irrespective of age, gender, or baseline dengue serostatus in recipients aged 4-60 years.
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Affiliation(s)
- Sanjay S Patel
- Correspondence: Sanjay S. Patel, PhD, Thurgauerstrasse 130, 8152 Glattpark-Opfikon (Zurich), Switzerland ()
| | | | - Maria Kudela
- Present affiliation: Pfizer, Cambridge, Massachusetts, USA
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13
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Elia-Amira NMR, Chen CD, Low VL, Lau KW, Haziqah-Rashid A, Amelia-Yap ZH, Lee HL, Sofian-Azirun M. Statewide Efficacy Assessment of Insect Growth Regulators Against Aedes albopictus (Diptera: Culicidae) in Sabah, Malaysia: An Alternative Control Strategy? JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:301-307. [PMID: 34459477 DOI: 10.1093/jme/tjab146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Indexed: 06/13/2023]
Abstract
The efficacy of three groups of insect growth regulators, namely juvenile hormone mimics (methoprene and pyriproxyfen), chitin synthesis inhibitors (diflubenzuron and novaluron), and molting disruptor (cyromazine) was evaluated for the first time, against Aedes albopictus Skuse (Diptera: Culicidae) larvae from 14 districts in Sabah, Malaysia. The results showed that all field populations of Ae. albopictus were susceptible towards methoprene, pyriproxyfen, diflubenzuron, novaluron, and cyromazine, with resistance ratio values ranging from 0.50-0.90, 0.60-1.00, 0.67-1.17, 0.71-1.29, and 0.74-1.07, respectively. Overall, the efficacy assessment of insect growth regulators in this study showed promising outcomes and they could be further explored as an alternative to conventional insecticides.
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Affiliation(s)
- N M R Elia-Amira
- Institute of Biological Sciences, Faculty of Science, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - C D Chen
- Institute of Biological Sciences, Faculty of Science, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
- Rimba Ilmu Botanical Garden, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - V L Low
- Higher Institution Centre of Excellence (HICoE), Tropical Infectious Diseases Research and Education Centre (TIDREC), Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - K W Lau
- Institute of Biological Sciences, Faculty of Science, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - A Haziqah-Rashid
- Institute of Biological Sciences, Faculty of Science, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - Z H Amelia-Yap
- Higher Institution Centre of Excellence (HICoE), Tropical Infectious Diseases Research and Education Centre (TIDREC), Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - H L Lee
- Medical Entomology Unit, Institute for Medical Research, Jalan Pahang, 50588, Kuala Lumpur, Malaysia
| | - M Sofian-Azirun
- Institute of Biological Sciences, Faculty of Science, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
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14
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Juvenile hormone analog enhances Zika virus infection in Aedes aegypti. Sci Rep 2021; 11:21062. [PMID: 34702871 PMCID: PMC8548497 DOI: 10.1038/s41598-021-00432-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 10/12/2021] [Indexed: 12/17/2022] Open
Abstract
In recent years, there has been a rise in the emergence of arboviruses of public health importance, including Zika, chikungunya, dengue, and yellow fever viruses. Insecticide-based mosquito control has been the primary method for mitigating transmission of arboviruses. The consequences for the application of insecticides include both lethal and sublethal effects, and associated development of insecticide resistance. However, little is known about the influence on arboviral transmission. Mosquitoes with phenotypes that exhibit insecticide resistance or experience sublethal effects may be associated with altered susceptibility to arbovirus infection and transmission. Juvenile hormone analogs (JHAs) are insecticides that prevent pupa to adult molting of mosquitoes by mimicking the action of their natural juvenile hormone. Here, we examined whether the JHA pyriproxyfen interacts with ambient temperature (20 °C and 30 °C) during juvenile stages to influence life-history traits, population growth (λ'), and Zika virus (ZIKV) infection in Aedes aegypti. Development time of females was lengthened at 20 °C and in the presence of JHA. Prevention of pupa to adult molting by JHA was differentially higher at elevated temperature than low temperature. Size of females was larger at 20 °C and smaller at 30 °C. Infection, disseminated infection, and transmission of ZIKV in females were enhanced by JHA at both 20 °C and 30 °C relative to the controls. These results demonstrate that mosquito life-history and vector competence parameters are strongly influenced by interactive effects of JHA and temperature. The JHA-induced enhancement of ZIKV infection in females should be a consideration when implementing JHA in vector control strategies.
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15
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Valbon WR, Hatano E, Oliveira NRX, Ataíde ÁD, Corrêa MJM, Gomes SF, Martins GF, Haddi K, Alvarenga ES, Oliveira EE. Detrimental effects of pyriproxyfen on the detoxification and abilities of Belostoma anurum to prey upon Aedes aegypti larvae. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 284:117130. [PMID: 33910136 DOI: 10.1016/j.envpol.2021.117130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 03/18/2021] [Accepted: 04/09/2021] [Indexed: 06/12/2023]
Abstract
Despite being effective in controlling mosquito larvae and a few other target organisms, the application of insecticides into aquatic systems may cause unintended alterations to the physiology or behavioral responses of several aquatic non-target organisms, which can ultimately lead to their death. Here, we firstly evaluated whether the susceptibility of the giant water bug, Belostoma anurum (Hemiptera: Belostomatidae), a predator of mosquito larvae, to pyriproxyfen would be similar to that of its potential prey, larvae of Aedes aegypti (Diptera: Culicidae). Secondly, we recorded the nominal concentrations of pyriproxyfen in water and evaluated whether sublethal exposures would lead to physiological or behavioral alterations on the B. anurum nymphs. We characterized the activities of three major families of detoxification enzymes (i.e., cytochrome P450 monooxygenases, glutathione-S-transferase, and general esterases) and further evaluated the abilities of pyriproxyfen sublethally-exposed B. anurum to prey upon A. aegypti larvae at different prey densities. Our findings revealed that nominal pyriproxyfen concentration significantly decreased (approximately 50%) over the first 24 h. Furthermore, when applied at the concentration of 10 μg a.i./L, pyriproxyfen was approximately four times more toxic to A. aegypti larvae (LT50 = 48 h) than to B. anurum nymphs (LT50 = 192 h). Interestingly, the pyriproxyfen sublethally-exposed (2.5 μg a.i./L) B. anurum nymphs exhibited reduced enzyme activities (cytochrome P450 monooxygenases) involved in detoxication processes and preyed significantly less on A. aegypti larvae when compared to unexposed predators. Collectively, our findings demonstrate that mortality-based pyriproxyfen risk assessments are not always protective of aquatic non-target organisms.
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Affiliation(s)
- Wilson R Valbon
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Eduardo Hatano
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, United States
| | | | - Álvaro D Ataíde
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | | | - Sabriny F Gomes
- Departamento de Química, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Gustavo F Martins
- Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Khalid Haddi
- Departamento de Entomologia, Universidade Federal de Lavras, Lavras, MG, Brazil
| | - Elson S Alvarenga
- Departamento de Química, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Eugênio E Oliveira
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, Brazil.
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16
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Mohd Ngesom AM, Ahmad Razi A, Azizan NS, Wasi Ahmad N, Md Lasim A, Liang Y, Greenhalgh D, Min JCS, Sahani M, Hod R, Othman H. Evaluation of a mosquito home system for controlling Aedes aegypti. Parasit Vectors 2021; 14:413. [PMID: 34407881 PMCID: PMC8375193 DOI: 10.1186/s13071-021-04918-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 08/02/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Dengue is a significant public health issue that is caused by Aedes spp. mosquitoes. The current vector control methods are unable to effectively reduce Aedes populations and thus fail to decrease dengue transmission. Hence, there is an urgent need for new tools and strategies to reduce dengue transmission in a wide range of settings. In this study, the Mosquito Home System (MHS) and Mosquito Home Aqua (MHAQ) formulations were assessed as commercial autodissemination traps in laboratory and small-scale field trials. METHOD Multiple series of laboratory and small-scale field trials were performed to assess the efficacy of MHS and MHAQ exposed to Ae. aegypti. In the laboratory trials, various parameters such as fecundity, fertility, wing size, oviposition preferences, residual effects, and MHAQ transference to other containers through controlled experiments were tested. For small-scale field trials, the efficacy of the MHS and MHAQ approaches was determined to ascertain whether wild mosquitoes could transfer the MHAQ formulation from MHS stations to ovitraps. RESULTS The data revealed that Ae. aegypti was highly susceptible to low concentrations of MHAQ formulations and had a residual effect of up to 3 months, with MHAQ exposure affecting fecundity, fertility, and mosquito wing size. In the oviposition studies, gravid females strongly preferred the hay infusion compared to tap water and MHAQ during egg-laying in the laboratory. Nevertheless, the use of commercial MHAQ by MHS was highly attractive in field settings compared to conventional ovitraps among local Aedes spp. mosquitoes. In addition, MHAQ horizontal transfer activities in the laboratory and small-scale field trials were demonstrated through larval bioassays. These findings demonstrated the potential of MHAQ to be transferred to new containers in each study site. CONCLUSION This study provided proof of principle for the autodissemination of MHAQ. Through further refinement, this technique and device could become an effective oviposition trap and offer an alternative preventive tool for vector control management.
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Affiliation(s)
- Ahmad Mohiddin Mohd Ngesom
- Center for Toxicology and Health Risk, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, 50300 Kuala Lumpur, Federal Territory of Kuala Lumpur, Malaysia
| | - Anis Ahmad Razi
- Center for Toxicology and Health Risk, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, 50300 Kuala Lumpur, Federal Territory of Kuala Lumpur, Malaysia
| | - Nur Syahirah Azizan
- Center for Toxicology and Health Risk, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, 50300 Kuala Lumpur, Federal Territory of Kuala Lumpur, Malaysia
| | - Nazni Wasi Ahmad
- Medical Entomology Unit, Infectious Disease Research Centre, Institute for Medical Research, National Institute of Health, Ministry of Health, 40170 Shah Alam, Selangor Malaysia
| | - Asmalia Md Lasim
- Phytochemistry Unit, Herbal Medicine Research Centre (HMRC), Institute for Medical Research, National Institute of Health, Ministry of Health, 40170 Shah Alam, Selangor Malaysia
| | - Yanfeng Liang
- Department of Mathematics and Statistics, University of Strathclyde, Glasgow, G1 1XH UK
| | - David Greenhalgh
- Department of Mathematics and Statistics, University of Strathclyde, Glasgow, G1 1XH UK
| | - Jasmine Chia Siew Min
- Department of Biomedical Science, Faculty of Medicine and Health Science, Universiti Putra Malaysia, 43400 Serdang, Selangor Malaysia
| | - Mazrura Sahani
- Center for Toxicology and Health Risk, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, 50300 Kuala Lumpur, Federal Territory of Kuala Lumpur, Malaysia
| | - Rozita Hod
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, 50600 Cheras, Kuala Lumpur, Malaysia
| | - Hidayatulfathi Othman
- Center for Toxicology and Health Risk, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, 50300 Kuala Lumpur, Federal Territory of Kuala Lumpur, Malaysia
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17
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Grisales N, Lees RS, Maas J, Morgan JC, Wangrawa DW, Guelbeogo WM, N'Fale S, Lindsay SW, McCall PJ, Ranson H. Pyriproxyfen-treated bed nets reduce reproductive fitness and longevity of pyrethroid-resistant Anopheles gambiae under laboratory and field conditions. Malar J 2021; 20:273. [PMID: 34158066 PMCID: PMC8218427 DOI: 10.1186/s12936-021-03794-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 05/30/2021] [Indexed: 11/21/2022] Open
Abstract
Background The efficacy of insecticide-treated nets (ITNs) containing the insect growth regulator pyriproxyfen (PPF) and pyrethroid insecticides (PPF-ITNs) is being assessed in clinical trials to determine whether they provide greater protection from malaria than standard pyrethroid-treated ITNs in areas where mosquitoes are resistant to pyrethroids. Understanding the entomological mode of action of this new ITN class will aide interpretation of the results from these trials. Methods Anopheles gambiae sensu lato (s.l.) mosquitoes from a susceptible laboratory strain were exposed to PPF-treated netting 24 h, 6 h, and immediately prior to, or 24 h post blood feeding, and the impact on fecundity, fertility and longevity recorded. Pyrethroid-resistant populations were exposed to nets containing permethrin and PPF (PPF-ITNs) in cone bioassays and daily mortality recorded. Mosquitoes were also collected from inside houses pre- and post-distribution of PPF-ITNs in a clinical trial conduced in Burkina Faso; female An. gambiae s.l. were then assessed for fecundity and fertility. Results PPF exposure reduced the median adult lifespan of insecticide-susceptible mosquitoes by 4 to 5 days in all exposure times (p < 0.05) other than 6 h pre-blood meal and resulted in almost complete lifelong sterilization. The longevity of pyrethroid-resistant mosquitoes was also reduced by at least 5 days after exposure to PPF-ITNs compared to untreated nets, but was unaffected by exposure to standard pyrethroid only ITNs. A total of 386 blood-fed or gravid An. gambiae s.l. females were collected from five villages between 1 and 12 months before distribution of PPF-ITNs. Of these mosquitoes, 75% laid eggs and the remaining 25% appeared to have normal ovaries upon dissection. In contrast, only 8.6% of the 631 blood-fed or gravid An. gambiae s.l. collected post PPF-ITN distribution successfully oviposited; 276 (43.7%) did not oviposit but had apparently normal ovaries upon dissection, and 301 (47.7%) did not oviposit and had abnormal eggs upon dissection. Egg numbers were also significantly lower (average of 138/female prior distribution vs 85 post distribution, p < 0.05). Conclusion Exposure to a mixture of PPF and pyrethroids on netting shortens the lifespan of mosquitoes and reduces reproductive output. Sterilization of vectors lasted at least one year under operational conditions. These findings suggest a longer effective lifespan of PPF-pyrethroid nets than reported previously. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03794-z.
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Affiliation(s)
- Nelson Grisales
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK.,World Mosquito Programme, Action On Poverty, Level 4, President Place, No. 93 Nguyen Du Street, District 1, Ho Chi Minh City, Vietnam
| | - Rosemary S Lees
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - James Maas
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - John C Morgan
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Dimitri W Wangrawa
- Centre National de Recherche Et de Formation Sur Le Paludisme (CNRFP), Rue 1847 Avenue Kunda Yonré, 01 BP 2208, Ouagadougou, Burkina Faso
| | - Wamdaogo M Guelbeogo
- Centre National de Recherche Et de Formation Sur Le Paludisme (CNRFP), Rue 1847 Avenue Kunda Yonré, 01 BP 2208, Ouagadougou, Burkina Faso
| | - Sagnon N'Fale
- Centre National de Recherche Et de Formation Sur Le Paludisme (CNRFP), Rue 1847 Avenue Kunda Yonré, 01 BP 2208, Ouagadougou, Burkina Faso
| | - Steven W Lindsay
- Department of Biosciences, Durham University, Durham, DH1 3LE, UK
| | - Philip J McCall
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Hilary Ranson
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK.
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18
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Susceptibility of South Texas Aedes aegypti to Pyriproxyfen. INSECTS 2021; 12:insects12050460. [PMID: 34067509 PMCID: PMC8157070 DOI: 10.3390/insects12050460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/10/2021] [Accepted: 05/15/2021] [Indexed: 12/01/2022]
Abstract
Simple Summary We evaluated the susceptibility of an Ae. aegypti strain from the Lower Rio Grande Valley (LRGV) of South Texas to the insect growth regulator pyriproxyfen. We observed a difference in the inhibition of emergence to the lowest doses of pyriproxyfen tested between our field strain and a susceptible strain. However, the doses used are 10 times lower from the recommended application of <50 ppb for vector control programs. Our results suggest that pyriproxyfen should be an effective active ingredient in the LRGV to help reduce Ae. aegypti populations in the LRGV. Abstract An integral part to integrated mosquito management is to ensure chemical products used for area-wide control are effective against a susceptible population of mosquitoes. Prior to conducting an intervention trial using an insect growth regulator, pyriproxyfen, in South Texas to control Aedes aegypti, we conducted a larval bioassay to evaluate baseline levels of susceptibility. We used seven serially-diluted doses ranging from 2.5 ppb to 6.3 × 10−4 ppb. We observed 100% inhibition emergence (IE) at even the lowest dose of 6.3 × 10−4 ppb in our susceptible reference colony of Ae. aegypti Liverpool. In our field strain of Ae. aegypti (F5 colonized from South Texas) we observed 79.8% IE at 6.3 × 10−4 ppb, 17.7% IE at 1.25 × 10−3 ppb, 98.7% IE at 1.25 × 10−2 ppb, and 100% emergence inhibition for the remainder of the doses. Given that commercial pyriproxyfen products are labeled for doses ranging to 50 ppb, we conclude that the field population sampled by this study are susceptible to this insect growth regulator.
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Douchet L, Haramboure M, Baldet T, L'Ambert G, Damiens D, Gouagna LC, Bouyer J, Labbé P, Tran A. Comparing sterile male releases and other methods for integrated control of the tiger mosquito in temperate and tropical climates. Sci Rep 2021; 11:7354. [PMID: 33795801 PMCID: PMC8016901 DOI: 10.1038/s41598-021-86798-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 03/19/2021] [Indexed: 11/09/2022] Open
Abstract
The expansion of mosquito species worldwide is creating a powerful network for the spread of arboviruses. In addition to the destruction of breeding sites (prevention) and mass trapping, methods based on the sterile insect technique (SIT), the autodissemination of pyriproxyfen (ADT), and a fusion of elements from both of these known as boosted SIT (BSIT), are being developed to meet the urgent need for effective vector control. However, the comparative potential of these methods has yet to be explored in different environments. This is needed to propose and integrate informed guidelines into sustainable mosquito management plans. We extended a weather-dependent model of Aedes albopictus population dynamics to assess the effectiveness of these different vector control methods, alone or in combination, in a tropical (Reunion island, southwest Indian Ocean) and a temperate (Montpellier area, southern France) climate. Our results confirm the potential efficiency of SIT in temperate climates when performed early in the year (mid-March for northern hemisphere). In such a climate, the timing of the vector control action was the key factor in its success. In tropical climates, the potential of the combination of methods becomes more relevant. BSIT and the combination of ADT with SIT were twice as effective compared to the use of SIT alone.
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Affiliation(s)
- Léa Douchet
- CIRAD, UMR ASTRE, 97491, Sainte-Clotilde, Reunion, France
- ASTRE, CIRAD, INRAE, Univ Montpellier, Montpellier, France
| | - Marion Haramboure
- CIRAD, UMR ASTRE, 97491, Sainte-Clotilde, Reunion, France.
- ASTRE, CIRAD, INRAE, Univ Montpellier, Montpellier, France.
- ISEM, CNRS, IRD, EPHE, Université de Montpellier, Montpellier, France.
- TETIS, AgroParisTech, CIRAD, CNRS, INRAE, Univ Montpellier, Montpellier, France.
| | - Thierry Baldet
- CIRAD, UMR ASTRE, 97491, Sainte-Clotilde, Reunion, France
- ASTRE, CIRAD, INRAE, Univ Montpellier, Montpellier, France
| | - Gregory L'Ambert
- Department of Research and Development, EID Méditerranée, Montpellier, France
| | - David Damiens
- IRD, CNRS-UM-IRD, UMR MIVEGEC, Montpellier, Reunion, France
- IRD/GIP CYROI, Sainte-Clotilde, Reunion, France
| | - Louis Clément Gouagna
- IRD, CNRS-UM-IRD, UMR MIVEGEC, Montpellier, Reunion, France
- IRD/GIP CYROI, Sainte-Clotilde, Reunion, France
| | - Jeremy Bouyer
- ASTRE, CIRAD, INRAE, Univ Montpellier, Montpellier, France
- CIRAD, UMR ASTRE, 34398, Montpellier, France
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, 1400, Vienna, Austria
- CIRAD, UMR ASTRE, 97410, Saint-Pierre, Reunion, France
| | - Pierrick Labbé
- ISEM, CNRS, IRD, EPHE, Université de Montpellier, Montpellier, France
| | - Annelise Tran
- CIRAD, UMR ASTRE, 97491, Sainte-Clotilde, Reunion, France
- ASTRE, CIRAD, INRAE, Univ Montpellier, Montpellier, France
- TETIS, AgroParisTech, CIRAD, CNRS, INRAE, Univ Montpellier, Montpellier, France
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Melo SJ, Sousa JPB, Sá MG, Morais LS, Magalhães NM, Gouveia FN, Albernaz LC, Espindola LS. Machaerium acutifolium compounds with larvicidal activity against Aedes aegypti. PEST MANAGEMENT SCIENCE 2021; 77:1444-1451. [PMID: 33128432 DOI: 10.1002/ps.6163] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 10/11/2020] [Accepted: 10/31/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Plant extracts and isolated compounds are known for their insecticidal activity. The Aedes aegypti mosquito has a significant medical impact as it transmits a number of arboviruses and is able to develop resistance to the commercially available insecticides. This study investigates larvicidal compounds isolated from Machaerium acutifolium, designated by the Brazilian Forest Service as a sustainable species. RESULTS A M. acutifolium trunk ethyl acetate extract was fractionated using chromatographic methods with full structural elucidation by mass spectrometry (MS), nuclear magnetic resonance and specific rotation analyses revealing: one new 3-arylcoumarin derivative 1; two flavonoids 2 and 3; a trans-stilbene 4, and an unprecedented natural indene 5. The larvicidal activity against Ae. aegypti after 24 h exposure was: crude extract (median lethal dose, LC50 205 mg L-1 ), fraction C (LC50 27 mg L-1 ) and 5 (LC50 24 mg L-1 ). CONCLUSION A M. acutifolium extract showed larvicidal activity, which increased with prolonged exposure, demonstrating LC50 75 mg L-1 after 72 h. Although the flavonoids 2 and 3 and trans-stilbene 4 were deemed inactive according to the adopted mortality limit, additional tests revealed their ability to cause 65% Ae. aegypti larvae mortality, suggesting they could contribute to the larvicidal activity. Compound 5, identified by liquid chromatography-MS, was over eight-fold more toxic to larvae than the crude extract after 24 h. Therefore, 5 constitutes a structural model for new prototypes to control Ae. aegypti. These data reinforce the potential of natural products as a source of commercial alternatives for vector control strategies, respecting both sustainability and eco-friendly principles. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Sebastião J Melo
- Laboratório de Farmacognosia, Universidade de Brasília, Campus Universitário Darcy Ribeiro, Brasília, Brazil
| | - João Paulo B Sousa
- Laboratório de Farmacognosia, Universidade de Brasília, Campus Universitário Darcy Ribeiro, Brasília, Brazil
| | - Maíra G Sá
- Laboratório de Farmacognosia, Universidade de Brasília, Campus Universitário Darcy Ribeiro, Brasília, Brazil
| | - Laís S Morais
- Laboratório de Farmacognosia, Universidade de Brasília, Campus Universitário Darcy Ribeiro, Brasília, Brazil
| | - Natália Mg Magalhães
- Laboratório de Farmacognosia, Universidade de Brasília, Campus Universitário Darcy Ribeiro, Brasília, Brazil
| | - Fernando N Gouveia
- Laboratório de Produtos Florestais, Serviço Florestal Brasileiro, Brasília, Brazil
| | - Lorena C Albernaz
- Laboratório de Farmacognosia, Universidade de Brasília, Campus Universitário Darcy Ribeiro, Brasília, Brazil
| | - Laila S Espindola
- Laboratório de Farmacognosia, Universidade de Brasília, Campus Universitário Darcy Ribeiro, Brasília, Brazil
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Alomar AA, Eastmond BH, Alto BW. The effects of exposure to pyriproxyfen and predation on Zika virus infection and transmission in Aedes aegypti. PLoS Negl Trop Dis 2020; 14:e0008846. [PMID: 33201875 PMCID: PMC7707533 DOI: 10.1371/journal.pntd.0008846] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 12/01/2020] [Accepted: 09/24/2020] [Indexed: 12/21/2022] Open
Abstract
Zika virus (ZIKV) is an emerging mosquito-borne pathogen that can cause global public health threats. In the absence of effective antiviral medications, prevention measures rely largely on reducing the number of adult mosquito vectors by targeting juvenile stages. Despite the importance of juvenile mosquito control measures in reducing adult population size, a full understanding of the effects of these measures in determining mosquito phenotypic traits and in mosquito-arbovirus interactions is poorly understood. Pyriproxyfen is a juvenile hormone analog that primarily blocks adult emergence, but does not cause mortality in larvae. This mechanism has the potential to work in combination with other juvenile sources of mortality in nature such as predation to affect mosquito populations. Here, we experimentally evaluated the effects of juvenile exposure to pyriproxyfen and predatory mosquito Toxorhynchites rutilus on Aedes aegypti phenotypes including susceptibility to ZIKV infection and transmission. We discovered that combined effects of pyriproxyfen and Tx. rutilus led to higher inhibition of adult emergence in Ae. aegypti than observed in pyriproxyfen or Tx. rutilus treatments alone. Adult body size was larger in treatments containing Tx. rutilus and in treatments mimicking the daily mortality of predation compared to control or pyriproxyfen treatments. Susceptibility to infection with ZIKV in Ae. aegypti was reduced in predator treatment relative to those exposed to pyriproxyfen. Disseminated infection, transmission, and titers of ZIKV in Ae. aegypti were similar in all treatments relative to controls. Our data suggest that the combination of pyriproxyfen and Tx. rutilus can inhibit adult Ae. aegypti emergence but may confer a fitness advantage in survivors and does not inhibit their vector competence for ZIKV relative to controls. Understanding the ultimate consequences of juvenile mosquito control measures on subsequent adults’ ability to transmit pathogens is critical to fully understand their overall impacts. Mosquito control approaches primarily depend on lowering the number of potential adult mosquito vectors by inhibiting juvenile stages to reduce the risk of pathogen transmission. Pyriproxyfen is a juvenile hormone analog that inhibits the emergence of adult mosquitoes by interrupting metamorphosis, but does not target larvae. This mechanism allows natural sources of mortality like predation to act in combination with pyriproxyfen to affect mosquito population size. Here, we determined the effects of juvenile exposure to pyriproxyfen and predatory mosquito Toxorhynchites rutilus on adult Aedes aegypti traits, including infection with Zika virus. Combined effects of pyriproxyfen and Tx. rutilus led to strong inhibition of adult emergence in Ae. aegypti. Treatments containing predators or those mimicking the daily mortality of predation produced larger sized adults. Susceptibility to ZIKV infection was lowest in the predator treatment and highest in the pyriproxyfen treatment. Disseminated infection, transmission, and viral titers of ZIKV were similar between treatments. Our data suggest that the combination of pyriproxyfen and predators can enhance inhibition of adult Ae. aegypti emergence, but survivors may have fitness benefits such being larger mosquitoes. Understanding the consequences of control approaches in mosquito-pathogen interactions will assist to evaluate their suitability in mosquito control programs.
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Affiliation(s)
- Abdullah A. Alomar
- University of Florida, Department of Entomology and Nematology, Florida Medical Entomology Laboratory, Vero Beach, Florida, United States of America
| | - Bradley H. Eastmond
- University of Florida, Department of Entomology and Nematology, Florida Medical Entomology Laboratory, Vero Beach, Florida, United States of America
| | - Barry W. Alto
- University of Florida, Department of Entomology and Nematology, Florida Medical Entomology Laboratory, Vero Beach, Florida, United States of America
- * E-mail:
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Morais HLMDN, Feitosa TC, Rodrigues JGM, Lira MGS, Nogueira RA, Luz TRSA, Silva-Souza N, Lima NM, Andrade TDJADS, Miranda GS. Hydroalcoholic extract of Caryocar brasiliense Cambess. leaves affect the development of Aedes aegypti mosquitoes. Rev Soc Bras Med Trop 2020; 53:e20200176. [PMID: 32935784 PMCID: PMC7491563 DOI: 10.1590/0037-8682-0176-2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 05/21/2020] [Indexed: 11/21/2022] Open
Abstract
INTRODUCTION: Curtailing the development of the aquatic immature stages of Aedes aegypti is one of the main measures to limit their spread and the diseases transmitted by them. The use of plant extracts is a promising approach in the development of natural insecticides. Thus, this research aimed to characterize the inhibitory effect of the hydroalcoholic extract of Caryocar brasiliense leaves on the emergence of adult A. aegypti and the main substances that constitute this extract. METHODS: C. brasiliense leaf extract was prepared by ethanol (70%) extraction. Bioassays using L3 larvae were performed at concentrations of 200, 300, 400, and 500 ppm. We identified the major secondary metabolites present in this extract, and performed toxicity tests on an off-target organism, Danio rerio. RESULTS: We observed a significant delay in the development of A. aegypti larvae mainly at a concentration of 500 ppm, and estimated an emergence inhibition for 50% of the population of 150 ppm. Moreover, the C. brasiliense leaf extracts exhibited low toxicity in D. rerio. The main compounds found in the extract were quercetin, violaxanthin, myricetin3-O-hexoside, methyl-elagic-3-arabinose acid, and isoquercitrin. CONCLUSIONS: Herein, we demonstrate the inhibition of mosquito development by the hydroalcoholic extract of C. brasiliense and suggest substances that may act as active principles.
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Affiliation(s)
| | | | | | | | | | | | - Nêuton Silva-Souza
- Universidade Estadual do Maranhão, Departamento de Química e Biologia, São Luís, MA, Brasil
| | - Nerilson Marques Lima
- Universidade Federal de Juiz de Fora, Departamento de Química, Juiz de Fora, MG, Brasil
| | | | - Guilherme Silva Miranda
- Instituto Federal de Educação, Ciência e Tecnologia do Maranhão, Departamento de Educação, São Raimundo das Mangabeiras, MA, Brasil.,Universidade Federal de Minas Gerais, Departamento de Parasitologia, Belo Horizonte, MG, Brasil
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Ahmed TH, Saunders TR, Mullins D, Rahman MZ, Zhu J. Molecular action of pyriproxyfen: Role of the Methoprene-tolerant protein in the pyriproxyfen-induced sterilization of adult female mosquitoes. PLoS Negl Trop Dis 2020; 14:e0008669. [PMID: 32866146 PMCID: PMC7485974 DOI: 10.1371/journal.pntd.0008669] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 09/11/2020] [Accepted: 08/03/2020] [Indexed: 01/02/2023] Open
Abstract
Exposure of adult mosquitoes to pyriproxyfen (PPF), an analog of insect juvenile hormone (JH), has shown promise to effectively sterilize female mosquitoes. However, the underlying mechanisms of the PPF-induced decrease in mosquito fecundity are largely unknown. We performed a comprehensive study to dissect the mode of PPF action in Aedes aegypti mosquitoes. Exposure to PPF prompted the overgrowth of primary follicles in sugar-fed Ae. aegypti females but blocked the development of primary follicles at Christopher’s Stage III after blood feeding. Secondary follicles were precociously activated in PPF-treated mosquitoes. Moreover, PPF substantially altered the expression of many genes that are essential for mosquito physiology and oocyte development in the fat body and ovary. In particular, many metabolic genes were differentially expressed in response to PPF treatment, thereby affecting the mobilization and utilization of energy reserves. Furthermore, PPF treatment on the previtellogenic female adults considerably modified mosquito responses to JH and 20-hydroxyecdysone (20E), two major hormones that govern mosquito reproduction. Krüppel homolog 1, a JH-inducible transcriptional regulator, showed consistently elevated expression after PPF exposure. Conversely, PPF upregulated the expression of several key players of the 20E regulatory cascades, including HR3 and E75A, in the previtellogenic stage. After blood-feeding, the expression of these 20E response genes was significantly weaker in PPF-treated mosquitoes than the solvent-treated control groups. RNAi-mediated knockdown of the Methoprene-tolerant (Met) protein, the JH receptor, partially rescued the impaired follicular development after PPF exposure and substantially increased the hatching of the eggs produced by PPF-treated female mosquitoes. Thus, the results suggested that PPF relied on Met to exert its sterilizing effects on female mosquitoes. In summary, this study finds that PPF exposure disturbs normal hormonal responses and metabolism in Ae. aegypti, shedding light on the molecular targets and the downstream signaling pathways activated by PPF. Aedes aegypti mosquitoes are responsible for the transmission of dengue, yellow fever, chikungunya, and Zika fever. Insecticides are widely used as the primary tool in the prevention and control of these infectious diseases. In light of the rapid increase of insecticide resistance in mosquito populations, there is an urgent need to find new classes of insecticides with a different mode of action. Here we found that pyriproxyfen, an analog of insect juvenile hormone (JH), had a large impact on the oocyte development, both before and after blood feeding, in female mosquitoes. Pyriproxyfen disturbed normal hormonal responses and caused metabolic shifting in female adults. These actions appear to collectively impair oocyte development and substantially reduce viable progenies of female mosquitoes. Besides, we demonstrated the involvement of the JH receptor Met in pyriproxyfen-induced female sterilization. This study significantly advances our understanding of mosquito reproductive biology and the molecular basis of pyriproxyfen action, which are invaluable for the development of new mosquito control strategies.
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Affiliation(s)
- Tahmina Hossain Ahmed
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, United States of America
| | - T. Randolph Saunders
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Donald Mullins
- Department of Entomology, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Mohammad Zillur Rahman
- Quantitative Science Core, Cancer Biology Division, Ponce Research Institute, Ponce Health Sciences University, Ponce, Puerto Rico
| | - Jinsong Zhu
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, United States of America
- * E-mail:
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Garcia KKS, Versiani HS, Araújo TO, Conceição JPA, Obara MT, Ramalho WM, Minuzzi-Souza TTC, Gomes GD, Vianna EN, Timbó RV, Barbosa VGC, Rezende MSP, Martins LPF, Macedo GO, Carvalho BL, Moreira IM, Bartasson LA, Nitz N, Luz SLB, Gurgel-Gonçalves R, Abad-Franch F. Measuring mosquito control: adult-mosquito catches vs egg-trap data as endpoints of a cluster-randomized controlled trial of mosquito-disseminated pyriproxyfen. Parasit Vectors 2020; 13:352. [PMID: 32665032 PMCID: PMC7362459 DOI: 10.1186/s13071-020-04221-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 07/08/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Aedes aegypti and Culex quinquefasciatus are the main urban vectors of arthropod-borne viruses causing human disease, including dengue, Zika, or West Nile. Although key to disease prevention, urban-mosquito control has met only limited success. Alternative vector-control tactics are therefore being developed and tested, often using entomological endpoints to measure impact. Here, we test one promising alternative and assess how three such endpoints perform at measuring its effects. METHODS We conducted a 16-month, two-arm, cluster-randomized controlled trial (CRCT) of mosquito-disseminated pyriproxyfen (MD-PPF) in central-western Brazil. We used three entomological endpoints: adult-mosquito density as directly measured by active aspiration of adult mosquitoes, and egg-trap-based indices of female Aedes presence (proportion of positive egg-traps) and possibly abundance (number of eggs per egg-trap). Using generalized linear mixed models, we estimated MD-PPF effects on these endpoints while accounting for the non-independence of repeated observations and for intervention-unrelated sources of spatial-temporal variation. RESULTS On average, MD-PPF reduced adult-mosquito density by 66.3% (95% confidence interval, 95% CI: 47.3-78.4%); Cx. quinquefasciatus density fell by 55.5% (95% CI: 21.1-74.8%), and Ae. aegypti density by 60.0% (95% CI: 28.7-77.5%). In contrast, MD-PPF had no measurable effect on either Aedes egg counts or egg-trap positivity, both of which decreased somewhat in the intervention cluster but also in the control cluster. Egg-trap data, therefore, failed to reflect the 60.0% mean reduction of adult Aedes density associated with MD-PPF deployment. CONCLUSIONS Our results suggest that the widely used egg-trap-based monitoring may poorly measure the impact of Aedes control; even if more costly, direct monitoring of the adult mosquito population is likely to provide a much more realistic and informative picture of intervention effects. In our CRCT, MD-PPF reduced adult-mosquito density by 66.3% in a medium-sized, spatially non-isolated, tropical urban neighborhood. Broader-scale trials will be necessary to measure MD-PPF impact on arboviral-disease transmission.
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Affiliation(s)
- Klauss K. S. Garcia
- Núcleo de Medicina Tropical, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
- Secretaria de Vigilância em Saúde, Ministério da Saúde, Brasilia, Brazil
| | - Hanid S. Versiani
- Laboratório de Parasitologia Médica e Biologia de Vetores, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
- Laboratório Interdisciplinar de Biociências, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
| | - Taís O. Araújo
- Laboratório de Parasitologia Médica e Biologia de Vetores, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
| | - João P. A. Conceição
- Núcleo de Medicina Tropical, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
- Laboratório de Parasitologia Médica e Biologia de Vetores, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
| | - Marcos T. Obara
- Núcleo de Medicina Tropical, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
- Laboratório de Parasitologia Médica e Biologia de Vetores, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
| | - Walter M. Ramalho
- Núcleo de Medicina Tropical, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
| | - Thaís T. C. Minuzzi-Souza
- Secretaria de Vigilância em Saúde, Ministério da Saúde, Brasilia, Brazil
- Laboratório de Parasitologia Médica e Biologia de Vetores, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
| | - Gustavo D. Gomes
- Laboratório de Parasitologia Médica e Biologia de Vetores, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
| | - Elisa N. Vianna
- Secretaria de Vigilância em Saúde, Ministério da Saúde, Brasilia, Brazil
- Laboratório de Parasitologia Médica e Biologia de Vetores, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
| | - Renata V. Timbó
- Laboratório de Parasitologia Médica e Biologia de Vetores, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
| | - Vinicios G. C. Barbosa
- Laboratório de Parasitologia Médica e Biologia de Vetores, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
| | - Maridalva S. P. Rezende
- Laboratório de Parasitologia Médica e Biologia de Vetores, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
| | - Luciana P. F. Martins
- Laboratório de Parasitologia Médica e Biologia de Vetores, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
| | - Glauco O. Macedo
- Laboratório de Parasitologia Médica e Biologia de Vetores, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
| | - Bruno L. Carvalho
- Núcleo de Medicina Tropical, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
| | - Israel M. Moreira
- Diretoria de Vigilância Ambiental em Saúde, Subsecretaria de Vigilância à Saúde, Secretaria de Estado de Saúde do Distrito Federal, Brasilia, Brazil
| | - Lorrainy A. Bartasson
- Diretoria de Vigilância Ambiental em Saúde, Subsecretaria de Vigilância à Saúde, Secretaria de Estado de Saúde do Distrito Federal, Brasilia, Brazil
| | - Nadjar Nitz
- Laboratório de Parasitologia Médica e Biologia de Vetores, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
- Laboratório Interdisciplinar de Biociências, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
| | - Sérgio L. B. Luz
- Instituto Leônidas e Maria Deane–Fiocruz Amazônia, Manaus, Brazil
| | - Rodrigo Gurgel-Gonçalves
- Núcleo de Medicina Tropical, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
- Laboratório de Parasitologia Médica e Biologia de Vetores, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
| | - Fernando Abad-Franch
- Núcleo de Medicina Tropical, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
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Hustedt JC, Boyce R, Bradley J, Hii J, Alexander N. Use of pyriproxyfen in control of Aedes mosquitoes: A systematic review. PLoS Negl Trop Dis 2020; 14:e0008205. [PMID: 32530915 PMCID: PMC7314096 DOI: 10.1371/journal.pntd.0008205] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 06/24/2020] [Accepted: 03/10/2020] [Indexed: 01/11/2023] Open
Abstract
Dengue is the most rapidly spreading arboviral disease in the world. The current lack of fully protective vaccines and clinical therapeutics creates an urgent need to identify more effective means of controlling Aedes mosquitos, principally Aedes aegypti, as the main vector of dengue. Pyriproxyfen (PPF) is an increasingly used hormone analogue that prevents juvenile Aedes mosquitoes from becoming adults and being incapable of transmitting dengue. The objectives of the review were to (1) Determine the effect of PPF on endpoints including percentage inhibition of emergence to adulthood, larval mortality, and resistance ratios; and (2) Determine the different uses, strengths, and limitations of PPF in control of Aedes. A systematic search was applied to Pubmed, EMBASE, Web of Science, LILACS, Global Health, and the Cochrane database of Systematic Reviews. Out of 1,369 records, 90 studies met the inclusion criteria. Nearly all fit in one of the following four categories 1) Efficacy of granules, 2) Auto-dissemination/horizontal transfer, 3) use of ultra-low volume thermal fogging (ULV), thermal fogging (TF), or fumigant technologies, and 4) assessing mosquito resistance. PPF granules had consistently efficacious results of 90-100% inhibition of emergence for up to 90 days. The evidence is less robust but promising regarding PPF dust for auto-dissemination and the use of PPF in ULV, TF and fumigants. Several studies also found that while mosquito populations were still susceptible to PPF, the lethal concentrations increased among temephos-resistant mosquitoes compared to reference strains. The evidence is strong that PPF does increase immature mortality and adult inhibition in settings represented in the included studies, however future research should focus on areas where there is less evidence (e.g. auto-dissemination, sprays) and new use cases for PPF. A better understanding of the biological mechanisms of cross-resistance between PPF, temephos, and other insecticides will allow control programs to make better informed decisions.
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Affiliation(s)
- John Christian Hustedt
- MRC Tropical Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Epidemiology Department, Malaria Consortium, London, United Kingdom
| | - Ross Boyce
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - John Bradley
- MRC Tropical Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Jeffrey Hii
- Epidemiology Department, Malaria Consortium, London, United Kingdom
| | - Neal Alexander
- MRC Tropical Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Modelling the control of Aedes albopictus mosquitoes based on sterile males release techniques in a tropical environment. Ecol Modell 2020. [DOI: 10.1016/j.ecolmodel.2020.109002] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Moura JAS, Souza-Santos LP. Environmental risk assessment (ERA) of pyriproxyfen in non-target aquatic organisms. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2020; 222:105448. [PMID: 32197184 DOI: 10.1016/j.aquatox.2020.105448] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 02/06/2020] [Accepted: 02/12/2020] [Indexed: 06/10/2023]
Abstract
Pyriproxyfen (PPF) is a synthetic substance and an insect juvenile hormone agonist with growth regulating effect. It is used worldwide as a pesticide in agriculture and public health campaigns, including the control of Aedes aegypti proliferation. It has low volatility, high Kow value and high lability in aerobic aquatic systems but is considered persistent in anaerobic systems, with a half-life of 288.9 days. The objective of this study is to survey the environmental contamination by pyriproxyfen in aquatic environmental matrices, to review the acute and chronic toxicity in non-target aquatic organisms and to make a risk assessment for the organisms addressed in the bibliographic survey. Pyriproxyfen quantification studies in aquatic environmental matrices are quite scarce and punctual-not representative of regional and global contamination. The water of the River Júcar (Spain) presented the highest concentration of PPF (99.59 ng L-1) among the matrices analysed, which is equivalent to 1% of the maximum dose allowed by the World Health Organization for use in drinking water. Acute and chronic aquatic toxicity studies with LC50, EC50, LOEC and NOEC values of PPF were compiled and interpreted to evaluate possible risks to non-target aquatic organisms. Pyriproxyfen caused a high risk at concentrations detected in aquatic environments for Daphnia magna, with probable reproductive effects and occasional survival risk. This species was the most sensitive to the pesticide, with the lowest estimated concentration of 50 % of effect values, followed by a freshwater fish (Xiphophorus maculatus) and estuarine crustaceans (Eurytemora affinis and Leander tenuicornis). The most resistant organisms to PPF within the endpoints addressed in this review were Danio rerio (zebrafish) and Capitella sp. (polychaete). Through the species sensitivity distribution (SSD), it was possible to estimate HC5 at 0.214 μg L-1 and that 2.3 % of the species present high sensitivity to pyriproxyfen in the environmental concentration detected in river water and 25.82 % of the species are affected in the concentration allowed for lavicidal use. In order to obtain more accurate risk estimates, we suggest ecotoxicological assessments in other species, covering various taxa, with emphasis on microcrustaceans due to their fundamental role in the aquatic food web and taxonomic proximity to pesticide target organisms. Furthermore, additional studies of contamination in aquatic environmental matrices are required, with particular attention to freshwater and estuarine environments due to the proximity to the sources of pyriproxyfen and environmental characteristics suggesting high accumulation. Thus, it will be possible to estimate realistic exposure levels and risks in different environments, contributing to effective and safe decision making, integrating development, public health and environmental policy.
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Affiliation(s)
- Jéssica A S Moura
- Laboratório de Cultivo e Ecotoxicologia, Departamento de Oceanografia, Universidade Federal de Pernambuco, Av. Arquitetura s/n, Cidade Universitária, Recife, CEP 50740-550, Pernambuco, Brazil.
| | - Lília P Souza-Santos
- Laboratório de Cultivo e Ecotoxicologia, Departamento de Oceanografia, Universidade Federal de Pernambuco, Av. Arquitetura s/n, Cidade Universitária, Recife, CEP 50740-550, Pernambuco, Brazil
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Devillers J. Fate and ecotoxicological effects of pyriproxyfen in aquatic ecosystems. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:16052-16068. [PMID: 32180143 DOI: 10.1007/s11356-020-08345-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 03/05/2020] [Indexed: 06/10/2023]
Abstract
Pyriproxyfen is an insect growth regulator acting as larvicide against a large spectrum of public health insect pests, especially dipterans. It is also widely used in agriculture and horticulture for the control of many insect species. Disrupting the endocrine system by mimicking the activity of the juvenile hormone, pyriproxyfen interferes with metamorphosis in insects and prevents them from reaching maturity and reproducing. Because the aquatic ecosystems can be directly or indirectly contaminated by pyriproxyfen, the goal of this study was to establish the aquatic ecotoxicological profile of pyriproxyfen and to identify the gaps that need to be filled. Pyriproxyfen is photodegraded quickly in water. In the absence of organic matter, its persistence in aerobic water media is also limited especially with high temperature and sunlight. Analysis of the laboratory and in situ results for more than 60 aquatic algae, plants, invertebrates, and vertebrates shows that the toxicity of pyriproxyfen is highly variable including within a same taxonomical group. Abiotic and biotic factors can highly influence the toxicity of the molecule. Pyriproxyfen disrupts the development of numerous species and adversely impacts various physiological events. It can also disturb the behavior of the organisms such as their predatory and swimming performances. Although some experimental studies focus on the environmental fate of pyriproxyfen metabolites, those dealing with their aquatic ecotoxicity assessment are scarce. In the same way, the limited number of studies dealing with the search of pyriproxyfen residues in lake, river, and other natural aquatic media does not include the identification of the metabolites.
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Chen YA, Lai YT, Wu KC, Yen TY, Chen CY, Tsai KH. Using UPLC-MS/MS to Evaluate the Dissemination of Pyriproxyfen by Aedes Mosquitoes to Combat Cryptic Larval Habitats after Source Reduction in Kaohsiung in Southern Taiwan. INSECTS 2020; 11:insects11040251. [PMID: 32316283 PMCID: PMC7240724 DOI: 10.3390/insects11040251] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/10/2020] [Accepted: 04/15/2020] [Indexed: 12/16/2022]
Abstract
The policy regarding mosquito control strategies in Taiwan is based on integrated vector management (IVM). The major approach is source reduction via collaboration by both residents and governments. However, small and cryptic habitats of dengue vectors are hard to find and eliminate in urban communities. Therefore, this study evaluated a complementary approach that targeted cryptic habitats by utilizing mosquitoes themselves as vehicles to transfer an insect growth regulator, pyriproxyfen (PPF), to their breeding sites; the amount of PPF in breeding water was determined with ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC–MS/MS). A bioassay conducted by introducing ten late-instar larvae into PPF solution was performed to assess emergence inhibition (EI). PPF was found at 0.56 ± 0.04 ng in 25 mL of water by dissemination via ten Aedes aegypti mosquitoes exposed to 0.01% PPF, leading to 100% EI. After the community-level source reduction, a field trial in Kaohsiung in Southern Taiwan showed that 30.8–31.5% of cryptic ovitraps reached EI ≥ 50% one month after spraying 0.01% PPF in microhabitats favored by mosquitoes. IVM in parallel with residual spraying of PPF on resting surfaces of mosquitoes could serve as a simple and complementary approach to reduce cryptic larval sources in urban communities in Southern Taiwan.
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Affiliation(s)
- Ying-An Chen
- Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, No. 17, Xuzhou Road, Taipei 100, Taiwan; (Y.-A.C.); (T.-Y.Y.); (C.-Y.C.)
| | - Yi-Ting Lai
- Master of Public Health Program, College of Public Health, National Taiwan University, No. 17, Xuzhou Road, Taipei 100, Taiwan;
| | - Kuo-Chih Wu
- National Mosquito-Borne Disease Control Research Center, National Health Research Institutes, No. 211, Zhongzheng 4th Rd., Qianjin Dist., Kaohsiung City 801, Taiwan;
| | - Tsai-Ying Yen
- Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, No. 17, Xuzhou Road, Taipei 100, Taiwan; (Y.-A.C.); (T.-Y.Y.); (C.-Y.C.)
| | - Chia-Yang Chen
- Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, No. 17, Xuzhou Road, Taipei 100, Taiwan; (Y.-A.C.); (T.-Y.Y.); (C.-Y.C.)
- Institute of Food Safety and Health, College of Public Health, National Taiwan University, No. 17, Xuzhou Road, Taipei 100, Taiwan
- Department of Public Health, College of Public Health, National Taiwan University, No. 17, Xuzhou Road, Taipei 100, Taiwan
| | - Kun-Hsien Tsai
- Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, No. 17, Xuzhou Road, Taipei 100, Taiwan; (Y.-A.C.); (T.-Y.Y.); (C.-Y.C.)
- Department of Public Health, College of Public Health, National Taiwan University, No. 17, Xuzhou Road, Taipei 100, Taiwan
- Department of Entomology, College of Bio-Resources and Agriculture, National Taiwan University, Insect Building: No. 27, Ln. 113, Sec. 4, Roosevelt Road, Taipei City 106, Taiwan
- Correspondence: ; Tel.: +886-2-33668103
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Horstick O, Runge-Ranzinger S. Multisectoral approaches for the control of vector-borne diseases, with particular emphasis on dengue and housing. Trans R Soc Trop Med Hyg 2019; 113:823-828. [PMID: 31034038 DOI: 10.1093/trstmh/trz020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 11/11/2018] [Accepted: 03/21/2019] [Indexed: 01/06/2023] Open
Abstract
The Sustainable Development Goals suggest an intersectoral approach for development and health, including for vector-borne diseases. Evidence-based policy recommendations exist for malaria and housing, but not for other, more underfunded, vector-borne diseases. This review aims to stimulate the process for developing policy recommendations for other vector-borne diseases and housing with the process as it was developed for dengue and Aedes control as an example and with suggestions for steps necessary for other vector-borne diseases. For dengue, some basic research on the efficacy of vector control in relation to housing exists, summary evidence highlights the lack of evidence and efficacy and policy recommendations remain difficult. For other vector-borne diseases, few studies have focused on protecting the house, combinations of effective interventions (e.g. intradomiciliary residual spraying, insecticide-treated materials and treatment of larval habitats with biological and chemical methods, which have proven to be effective) have not been studied and summary evidence is non-existent. In order to recommend vector control to protect the house against vector-borne diseases, basic research and summary evidence are needed, with an appropriate combination of the most efficacious interventions and linked to improvement of housing itself. Standards for such studies need to be developed.
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Yadav K, Dhiman S, Acharya BN, Ghorpade RR, Sukumaran D. Pyriproxyfen treated surface exposure exhibits reproductive disruption in dengue vector Aedes aegypti. PLoS Negl Trop Dis 2019; 13:e0007842. [PMID: 31738760 PMCID: PMC6886876 DOI: 10.1371/journal.pntd.0007842] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 12/02/2019] [Accepted: 10/13/2019] [Indexed: 11/21/2022] Open
Abstract
Background Reduced susceptibility of mosquito vectors to currently used insecticides hampers control interventions. Recently pyriproxyfen, an insect growth regulator has been demonstrated to effectively reduce the reproductive potential in vector mosquitoes. Methods Pyriproxyfen (PPF), in different concentrations (0.75%, 0.075%, 0.0075%, and 0.00075%) was applied on papers and Indian wild type Aedes aegypti female mosquitoes (N ≥ 20 for each treatment) were exposed onto it as per WHO guidelines, to study the reproductive disruption. PPF concentration on treated papers was quantitatively cross-determined using HPLC method. Reduction in fecundity, fertility and adult emergence in exposed female Ae. aegypti was determined. Abnormal development in ovary and eggs of exposed females was studied microscopically after different time intervals. Results Eggs laid, eggs hatched, pupae formed and adults emerged per female exposed in both before blood meal and after blood meal groups declined significantly from lowest to highest concentration of PPF (F ≥ 5.2; p < 0.02). Adult emergence inhibition in females exposed to PPF before and after blood meal groups ranged from 58.8% [OR = 0.18 (95% CI = 0.09–0.36)] to 79.2% [OR = 0.04 (95% CI = 0.02–0.10)] and 64.4% [OR = 0.12 (95% CI = 0.05–0.28)] to 77.1% [OR = 0.05 (95% CI = 0.02–0.14)] respectively in different concentrations. The probit model used suggested that FI50 (50% fertility inhibition) and EI50 (50% emergence inhibition) were 0.002% (p = 0.82) and 0.0001% (p = 0.99) for females exposed before blood meal, while 0.01% (p = 0.63) and <0.0001% (p = 0.98) for the females exposed after blood meal, respectively. The eggs laid by the females exposed to PPF-treated surface showed altered body organization, desegmentation and disoriented abdominal and cervical regions in the developing embryo. Quantification of PPF on impregnated papers showed that it was uniformly distributed throughout the matrix. Conclusions The present study has shown that tarsal contact to PPF-treated surface for a small time drastically influenced the fecundity, fertility and adult emergence in Indian wild Ae. aegypti mosquitoes. Results suggest that a certain minimum concentration of PPF through contact exposure can reduce the abundance of vector mosquitoes to a considerable level. The formulations based on combination of PPF and other compatible insecticides may be an impactful approach where susceptible mosquitoes are killed by the insecticide component while resistant mosquitoes are sterilised by PPF. Development of resistance against insecticides has challenged mosquito control programmes globally and prompted the research of alternative options that can complement insecticides. An insect growth regulator, pyriproxyfen (PPF) usage against mosquitoes can effectively reduce the vector population. PPF mainly inhibits the metamorphosis of mosquito larvae into pupae and prevent the adult emergence, therefore it is generally applied in mosquito breeding habitats. PPF has been shown to exhibit delayed residual effect that may impair the reproductive capacity by affecting the survival, fecundity and fertility of adult mosquito exposed through tarsal contact. Presently, the effectiveness of different concentrations of PPF intended to be delivered through contact have been evaluated against dengue vector Ae. aegypti. Results suggested that very low PPF concentration treated surfaces drastically reduce the fecundity, fertility and adult emergence in mosquitoes. Study suggests that control interventions based on PPF-treated surfaces could provide an additional route to target mosquito vector control by overall population density reduction.
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Affiliation(s)
- Kavita Yadav
- Vector Management Division, Defence Research and Development Establishment, Gwalior, Madhya Pradesh, India
- * E-mail:
| | - Sunil Dhiman
- Vector Management Division, Defence Research and Development Establishment, Gwalior, Madhya Pradesh, India
| | - BN Acharya
- Synthetic Chemistry Division, Defence Research and Development Establishment, Gwalior, Madhya Pradesh, India
| | - Rama Rao Ghorpade
- Synthetic Chemistry Division, Defence Research and Development Establishment, Gwalior, Madhya Pradesh, India
| | - Devanathan Sukumaran
- Vector Management Division, Defence Research and Development Establishment, Gwalior, Madhya Pradesh, India
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Foxi C, Delrio G, Luciano P, Mannu R, Ruiu L. Comparative laboratory and field study of biorational insecticides for Culicoides biting midge management in larval developmental sites. Acta Trop 2019; 198:105097. [PMID: 31325415 DOI: 10.1016/j.actatropica.2019.105097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 07/16/2019] [Accepted: 07/16/2019] [Indexed: 12/24/2022]
Abstract
An appropriate management strategy of bluetongue vectors should include larvicidal treatments in their larval development sites utilizing active substances with low environmental impact. A selection of biorational insecticides with potential against dipteran larvae was assayed in the laboratory against field collected Culicoides larvae including C. cataneii, C. circumscriptus, and C. imicola, determining their median lethal concentrations in water and mud/water substrate. The efficacy of formulations containing the insect growth regulators pyriproxyfen and cyromazine, the botanical insecticide azadirachtin, and the entomopathogenic bacteria Bacillus thuringiensis israelensis and Brevibacillus laterosporus, was also assessed in field conditions in a comparative study conducted in sheep farm larval development sites, including treatments with the organophosphate temephos. Significant larvicidal properties were associated with the various insecticides evaluated in the laboratory assays and in field trials, although with different levels of effectiveness. While temephos was confirmed to be an effective broad spectrum larvicidal substance, B. laterosporus appeared to be the most effective among entomopathogens, while insect growth regulators combined a good efficacy to a long-lasting residual effect in the field. Everything considered, the use of these biorational insecticides alone or in combination with larval habitat manipulation techniques appears to be a promising method to complement integrated biting midge management programs.
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Bui M, Shyong J, Lutz EK, Yang T, Li M, Truong K, Arvidson R, Buchman A, Riffell JA, Akbari OS. Live calcium imaging of Aedes aegypti neuronal tissues reveals differential importance of chemosensory systems for life-history-specific foraging strategies. BMC Neurosci 2019; 20:27. [PMID: 31208328 PMCID: PMC6580577 DOI: 10.1186/s12868-019-0511-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 06/10/2019] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND The mosquito Aedes aegypti has a wide variety of sensory pathways that have supported its success as a species as well as a highly competent vector of numerous debilitating infectious pathogens. Investigations into mosquito sensory systems and their effects on behavior are valuable resources for the advancement of mosquito control strategies. Numerous studies have elucidated key aspects of mosquito sensory systems, however there remains critical gaps within the field. In particular, compared to that of the adult form, there has been a lack of studies directed towards the immature life stages. Additionally, although numerous studies have pinpointed specific sensory receptors as well as responding motor outputs, there has been a lack of studies able to monitor both concurrently. RESULTS To begin filling aforementioned gaps, here we engineered Ae. aegypti to ubiquitously express a genetically encoded calcium indicator, GCaMP6s. Using this strain, combined with advanced microscopy, we simultaneously measured live stimulus-evoked calcium responses in both neuronal and muscle cells with a wide spatial range and resolution. CONCLUSIONS By coupling in vivo live calcium imaging with behavioral assays we were able to gain functional insights into how stimulus-evoked neural and muscle activities are represented, modulated, and transformed in mosquito larvae enabling us to elucidate mosquito sensorimotor properties important for life-history-specific foraging strategies.
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Affiliation(s)
- Michelle Bui
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093 USA
| | - Jennifer Shyong
- Department of Entomology and Riverside Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA 92521 USA
| | - Eleanor K. Lutz
- Department of Biology, University of Washington, Seattle, WA 98195 USA
| | - Ting Yang
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093 USA
| | - Ming Li
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093 USA
| | - Kenneth Truong
- Department of Entomology and Riverside Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA 92521 USA
| | - Ryan Arvidson
- Department of Entomology and Riverside Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA 92521 USA
| | - Anna Buchman
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093 USA
| | | | - Omar S. Akbari
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093 USA
- Tata Institute for Genetics and Society, University of California, San Diego, La Jolla, CA 92093 USA
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Salazar F, Angeles J, Sy AK, Inobaya MT, Aguila A, Toner T, Bangs MJ, Thomsen E, Paul RE. Efficacy of the In2Care® auto-dissemination device for reducing dengue transmission: study protocol for a parallel, two-armed cluster randomised trial in the Philippines. Trials 2019; 20:269. [PMID: 31088515 PMCID: PMC6518692 DOI: 10.1186/s13063-019-3376-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 04/19/2019] [Indexed: 12/26/2022] Open
Abstract
Background Mosquito-borne viruses are imposing an ever increasing health burden worldwide. In addition to the recent Zika and chikungunya virus epidemics, dengue viruses have become the fastest growing problem with a 40-fold increase in the number of reported cases over the past five decades. Current mosquito control techniques involving larval source reduction, larviciding, and space spray of adulticides are costly, laborious, and of debatable efficacy. There remains an urgent need for the development of intervention methods that can be reasonably implemented in the context of modern day urbanisation. Auto-dissemination (AD) of insecticide by adult mosquitoes offers a potentially practical and useful tool in an integrated vector control programme. Recently, an immediately employable AD device, the In2Care® mosquito trap, has been commercialised and shows promise as an effective tool. However, there remains a lack of demonstration of epidemiological efficacy. Methods/design This trial aims to assess the extent to which implementation of In2Care® mosquito traps can reduce vector Aedes (Stegomyia) spp. adult mosquito densities and dengue virus transmission as measured by sequential sero-conversion rates in children 6–16 years of age in a dengue endemic location: Lipa City, Philippines. To achieve this, we will carry out a parallel, two-armed cluster randomised trial evaluating AD efficacy for reducing the incidence of dengue over a 2-year period with 4 consecutive months of vector control during peak dengue transmission each year. Discussion For decades, it has been commonly accepted that an integrated approach to mosquito control is required. The World Health Organization (WHO) Global Strategic Framework for Integrated Vector Management recommends a range of interventions, in combination, to increase control impact to reduce transmission. This efficacy trial of the first commercial product using the AD approach will be informative in assessing the general utility of AD in reducing not only adult vector densities but, more importantly, reducing the incidence of dengue. The AD technique may complement source reduction and larviciding campaigns by more efficiently targeting the most productive containers and those beyond human reach. If successful, this mosquito control strategy could prove an invaluable tool in the fight against urban mosquito vectors and a reduction in the burden of associated disease. Trial registration ISRCTN44272773. Registered on 31 January 2019. Electronic supplementary material The online version of this article (10.1186/s13063-019-3376-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ferdinand Salazar
- Department of Medical Entomology, Research Institute for Tropical Medicine, Filinvest City Alabang, Muntinlupa City, Philippines
| | - Jason Angeles
- Department of Medical Entomology, Research Institute for Tropical Medicine, Filinvest City Alabang, Muntinlupa City, Philippines
| | - Ava Kristy Sy
- Department of Virology, Research Institute for Tropical Medicine, Filinvest City Alabang, Muntinlupa City, Philippines
| | - Marianette T Inobaya
- Department of Epidemiology and Biostatistics, Research Institute for Tropical Medicine, Filinvest City Alabang, Muntinlupa City, Philippines
| | - Ariza Aguila
- Department of Medical Entomology, Research Institute for Tropical Medicine, Filinvest City Alabang, Muntinlupa City, Philippines
| | - Tom Toner
- Liverpool School of Tropical Medicine, Liverpool, UK
| | - Michael J Bangs
- PT Freeport Indonesia/International SOS, Kuala Kencana, Indonesia. .,Kasetsart University, Bangkok, Thailand.
| | | | - Richard E Paul
- Functional Genetics of Infectious Diseases Unit, Institut Pasteur, Paris, France. .,Génomique évolutive, modélisation et santé UMR 2000, Centre National de la Recherche Scientifique (CNRS), Paris, France.
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Horstick O, Boyce R, Runge-Ranzinger S. Building the evidence base for dengue vector control: searching for certainty in an uncertain world. Pathog Glob Health 2018; 112:395-403. [PMID: 30521408 PMCID: PMC6327620 DOI: 10.1080/20477724.2018.1547541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
This review discusses biological and chemical methods for dengue vector control, using recently emerging summary evidence, meta-analyses and systematic reviews to conclude on practical public health recommendations for Aedes control, which is increasingly relevant in an era of widespread Chikungunya, yellow feer and Zika outbreaks. The analysis follows an a priori framework of systematic reviews by the authors on vector control methods, distinguishing vector control methods into biological, chemical and environmental methods. Findings of each published systematic review by the authors, following each individual vector control method, are summarised and compared in the discussion against the findings of existing meta-analyses covering all vector control methods. Analysing nine systematic reviews and comparing to two existing meta-analyses provided low-to-moderate evidence that the control of Aedes mosquitoes can be achieved using 1) chemical methods, particularly indoor residual spraying and insecticide treated materials, and 2) biological methods, where appropriate. The level of efficacy and community effectiveness of the methods in most studies analysed is low, as was the overall assessment of study quality. Furthermore, the results show that too optimise results, larvae and adults should be targeted simultaneously. The quality of service delivery is probably one of the most important features of this analysis - and including high coverage. The analysis also highlights the urgent need for standards to guide the design and reporting of vector control studies, ensuring the validity and comparability of results. These studies should aim to include measurements of human transmission data - where and when possible.
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Affiliation(s)
- Olaf Horstick
- Heidelberg Institute of Global Health, University of Heidelberg, Germany
| | - Ross Boyce
- Division of Infectious Diseases, University of North Carolina, Chapel Hill, NC, USA
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Roiz D, Wilson AL, Scott TW, Fonseca DM, Jourdain F, Müller P, Velayudhan R, Corbel V. Integrated Aedes management for the control of Aedes-borne diseases. PLoS Negl Trop Dis 2018; 12:e0006845. [PMID: 30521524 PMCID: PMC6283470 DOI: 10.1371/journal.pntd.0006845] [Citation(s) in RCA: 129] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Diseases caused by Aedes-borne viruses, such as dengue, Zika, chikungunya, and yellow fever, are emerging and reemerging globally. The causes are multifactorial and include global trade, international travel, urbanisation, water storage practices, lack of resources for intervention, and an inadequate evidence base for the public health impact of Aedes control tools. National authorities need comprehensive evidence-based guidance on how and when to implement Aedes control measures tailored to local entomological and epidemiological conditions. METHODS AND FINDINGS This review is one of a series being conducted by the Worldwide Insecticide resistance Network (WIN). It describes a framework for implementing Integrated Aedes Management (IAM) to improve control of diseases caused by Aedes-borne viruses based on available evidence. IAM consists of a portfolio of operational actions and priorities for the control of Aedes-borne viruses that are tailored to different epidemiological and entomological risk scenarios. The framework has 4 activity pillars: (i) integrated vector and disease surveillance, (ii) vector control, (iii) community mobilisation, and (iv) intra- and intersectoral collaboration as well as 4 supporting activities: (i) capacity building, (ii) research, (iii) advocacy, and (iv) policies and laws. CONCLUSIONS IAM supports implementation of the World Health Organisation Global Vector Control Response (WHO GVCR) and provides a comprehensive framework for health authorities to devise and deliver sustainable, effective, integrated, community-based, locally adapted vector control strategies in order to reduce the burden of Aedes-transmitted arboviruses. The success of IAM requires strong commitment and leadership from governments to maintain proactive disease prevention programs and preparedness for rapid responses to outbreaks.
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Affiliation(s)
- David Roiz
- MIVEGEC, IRD, CNRS, University of Montpellier, Montpellier, France
| | - Anne L Wilson
- Department of Biosciences, Durham University, Durham, United Kingdom
| | - Thomas W Scott
- Department of Entomology & Nematology, University of California, Davis, California, United States of America
| | - Dina M Fonseca
- Center for Vector Biology, Rutgers University, New Brunswick, New Jersey, United States of America
| | | | - Pie Müller
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Raman Velayudhan
- Department of Control of Neglected Tropical Diseases (HTM/NTD), World Health Organization (WHO), Geneva, Switzerland
| | - Vincent Corbel
- MIVEGEC, IRD, CNRS, University of Montpellier, Montpellier, France
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Olliaro P, Fouque F, Kroeger A, Bowman L, Velayudhan R, Santelli AC, Garcia D, Skewes Ramm R, Sulaiman LH, Tejeda GS, Morales FC, Gozzer E, Garrido CB, Quang LC, Gutierrez G, Yadon ZE, Runge-Ranzinger S. Improved tools and strategies for the prevention and control of arboviral diseases: A research-to-policy forum. PLoS Negl Trop Dis 2018; 12:e0005967. [PMID: 29389959 PMCID: PMC5794069 DOI: 10.1371/journal.pntd.0005967] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Research has been conducted on interventions to control dengue transmission and respond to outbreaks. A summary of the available evidence will help inform disease control policy decisions and research directions, both for dengue and, more broadly, for all Aedes-borne arboviral diseases. METHOD A research-to-policy forum was convened by TDR, the Special Programme for Research and Training in Tropical Diseases, with researchers and representatives from ministries of health, in order to review research findings and discuss their implications for policy and research. RESULTS The participants reviewed findings of research supported by TDR and others. Surveillance and early outbreak warning. Systematic reviews and country studies identify the critical characteristics that an alert system should have to document trends reliably and trigger timely responses (i.e., early enough to prevent the epidemic spread of the virus) to dengue outbreaks. A range of variables that, according to the literature, either indicate risk of forthcoming dengue transmission or predict dengue outbreaks were tested and some of them could be successfully applied in an Early Warning and Response System (EWARS). Entomological surveillance and vector management. A summary of the published literature shows that controlling Aedes vectors requires complex interventions and points to the need for more rigorous, standardised study designs, with disease reduction as the primary outcome to be measured. House screening and targeted vector interventions are promising vector management approaches. Sampling vector populations, both for surveillance purposes and evaluation of control activities, is usually conducted in an unsystematic way, limiting the potentials of entomological surveillance for outbreak prediction. Combining outbreak alert and improved approaches of vector management will help to overcome the present uncertainties about major risk groups or areas where outbreak response should be initiated and where resources for vector management should be allocated during the interepidemic period. CONCLUSIONS The Forum concluded that the evidence collected can inform policy decisions, but also that important research gaps have yet to be filled.
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Affiliation(s)
- Piero Olliaro
- UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, Geneva, Switzerland
| | - Florence Fouque
- UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, Geneva, Switzerland
| | - Axel Kroeger
- UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, Geneva, Switzerland
- Global Health Department, Centre for Medicine and Society/Anthropology, Freiburg University, Freiburg im Breisgau, Germany
| | - Leigh Bowman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Raman Velayudhan
- Department of Control of Neglected Tropical Diseases (WHO/NTD), World Health Organization, Geneva, Switzerland
| | | | - Diego Garcia
- Department of Communicable Diseases, Ministry of Health, Bogota, Colombia
| | - Ronald Skewes Ramm
- Program for the Prevention and Control of Dengue, Ministry of Health, Santo Domingo, Dominican Republic
| | | | - Gustavo Sanchez Tejeda
- Centro Nacional de Programas Preventivos y Control de Enfermedades (CENAPRECE), Ministry of Health, Mexico City, Mexico
| | - Fabiàn Correa Morales
- Centro Nacional de Programas Preventivos y Control de Enfermedades (CENAPRECE), Ministry of Health, Mexico City, Mexico
| | | | | | - Luong Chan Quang
- Department for Disease Control and Prevention, Pasteur Institute, Ho Chi Minh City, Vietnam
| | - Gamaliel Gutierrez
- PAHO/AMRO, World Health Organization, Washington, DC, United States of America
| | - Zaida E. Yadon
- PAHO/AMRO, World Health Organization, Rio de Janeiro, Brazil
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Kenneson A, Beltrán-Ayala E, Borbor-Cordova MJ, Polhemus ME, Ryan SJ, Endy TP, Stewart-Ibarra AM. Social-ecological factors and preventive actions decrease the risk of dengue infection at the household-level: Results from a prospective dengue surveillance study in Machala, Ecuador. PLoS Negl Trop Dis 2017; 11:e0006150. [PMID: 29253873 PMCID: PMC5771672 DOI: 10.1371/journal.pntd.0006150] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 01/17/2018] [Accepted: 12/03/2017] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND In Ecuador, dengue virus (DENV) infections transmitted by the Aedes aegypti mosquito are among the greatest public health concerns in urban coastal communities. Community- and household-level vector control is the principal means of controlling disease outbreaks. This study aimed to assess the impact of knowledge, attitudes, and practices (KAPs) and social-ecological factors on the presence or absence of DENV infections in the household. METHODS In 2014 and 2015, individuals with DENV infections from sentinel clinics in Machala, Ecuador, were invited to participate in the study, as well as members of their household and members of four neighboring households located within 200 meters. We conducted diagnostic testing for DENV on all study participants; we surveyed heads of households (HOHs) regarding demographics, housing conditions and KAPs. We compared KAPs and social-ecological factors between households with (n = 139) versus without (n = 80) DENV infections, using bivariate analyses and multivariate logistic regression models with and without interactions. RESULTS Significant risk factors in multivariate models included proximity to abandoned properties, interruptions in piped water, and shaded patios (p<0.05). Significant protective factors included the use of mosquito bed nets, fumigation inside the home, and piped water inside the home (p<0.05). In bivariate analyses (but not multivariate modeling), DENV infections were positively associated with HOHs who were male, employed, and of younger age than households without infections (p<0.05). DENV infections were not associated with knowledge, attitude, or reported barriers to prevention activities. DISCUSSION Specific actions that can be considered to decrease the risk of DENV infections in the household include targeting vector control in highly shaded properties, fumigating inside the home, and use of mosquito bed nets. Community-level interventions include cleanup of abandoned properties, daily garbage collection, and reliable piped water inside houses. These findings can inform interventions to reduce the risk of other diseases transmitted by the Ae. aegypti mosquito, such as chikungunya and Zika fever.
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Affiliation(s)
- Aileen Kenneson
- Center for Global Health & Translational Sciences, SUNY Upstate Medical University, Syracuse, NY, United States of America
| | - Efraín Beltrán-Ayala
- Facultad de Medicina, Universidad Técnica de Machala, Machala, El Oro Province, Ecuador
| | - Mercy J. Borbor-Cordova
- Facultad de Ingeniería Marítima, Ciencias Biológicas, Oceánicas y Recursos Naturales, Escuela Superior Politecnica del Litoral (ESPOL), Guayaquil, Ecuador
| | - Mark E. Polhemus
- Center for Global Health & Translational Sciences, SUNY Upstate Medical University, Syracuse, NY, United States of America
- Department of Medicine, SUNY Upstate Medical University, Syracuse, NY, United States of America
| | - Sadie J. Ryan
- Center for Global Health & Translational Sciences, SUNY Upstate Medical University, Syracuse, NY, United States of America
- Department of Geography, University of Florida, Gainesville, FL, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States of America
- College of Life Sciences, University of Kwazulu-Natal, Durban, South Africa
| | - Timothy P. Endy
- Center for Global Health & Translational Sciences, SUNY Upstate Medical University, Syracuse, NY, United States of America
- Department of Medicine, SUNY Upstate Medical University, Syracuse, NY, United States of America
- Department of Microbiology & Immunology, SUNY Upstate Medical University, Syracuse, NY, United States of America
| | - Anna M. Stewart-Ibarra
- Center for Global Health & Translational Sciences, SUNY Upstate Medical University, Syracuse, NY, United States of America
- Department of Medicine, SUNY Upstate Medical University, Syracuse, NY, United States of America
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