Suppression of Dengue Transmission by Application of Integrated Vector Control Strategies at Sero-Positive GIS-Based Foci

AbstractCulex mosquitoes particularly Culex quinquefasciatus are important arboviral and filariasis vectors, however despite this important epidemiological role, there is still a paucity of data on their bionomics. The present study was undertaken to assess the insecticide resistance status of Cx. quinquefasciatus populations from four districts of Yaoundé (Cameroon). All Culex quinquefasciatus populations except one displayed high resistance to bendiocarb and malathion with mortalities ranging from 0 to 89% while high resistance intensity against both permethrin and deltamethrin was recorded. Molecular analyses revealed high frequencies of the ACE-1 G119S mutation (ranging from 0 to 33%) and kdr L1014F allele (ranging from 55 to 74%) in all Cx. quinquefasciatus populations. Significant overexpression was detected for cytochrome P450s genes CYP6AA7 and CYP6Z10, as well as for Esterase A and Esterase B genes. The total cuticular hydrocarbon content, a proxy of cuticular resistance, was significantly increased (compared to the S-lab strain) in one population. The study confirms strong insecticide resistance mediated by different mechanisms in Cx. quinquefasciatus populations from the city of Yaoundé. The expansion of insecticide resistance in Culex populations could affect the effectiveness of current vector control measures and stress the need for the implementation of integrated vector control strategies in urban settings.

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A Two-Patch Mathematical Model for Temperature-Dependent Dengue Transmission Dynamics

Processes ◽

10.3390/pr8070781 ◽

2020 ◽

Vol 8 (7) ◽

pp. 781

Author(s):

Jung Kim ◽

Yongin Choi ◽

James Kim ◽

Sunmi Lee ◽

Chang Lee

Keyword(s):

Climate Change ◽

Vector Control ◽

Control Strategies ◽

Virus Transmission ◽

Transmission Dynamics ◽

Transmission Control ◽

Temperature Dependent ◽

Tropical Regions ◽

Patch Model ◽

Dengue Transmission

Dengue fever has been a threat to public health not only in tropical regions but non-tropical regions due to recent climate change. Motivated by a recent dengue outbreak in Japan, we develop a two-patch model for dengue transmission associated with temperature-dependent parameters. The two patches represent a park area where mosquitoes prevail and a residential area where people live. Based on climate change scenarios, we investigate the dengue transmission dynamics between the patches. We employ an optimal control method to implement proper control measures in the two-patch model. We find that blockage between two patches for a short-term period is effective in a certain degree for the disease control, but to obtain a significant control effect of the disease, a long-term blockage should be implemented. Moreover, the control strategies such as vector control and transmission control are very effective, if they are implemented right before the summer outbreak. We also investigate the cost-effectiveness of control strategies such as vaccination, vector control and virus transmission control. We find that vector control and virus transmission control are more cost-effective than vaccination in case of Korea.

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Predicting Aedes aegypti infestation using landscape and thermal features

Scientific Reports ◽

10.1038/s41598-020-78755-8 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Camila Lorenz ◽

Marcia C. Castro ◽

Patricia M. P. Trindade ◽

Maurício L. Nogueira ◽

Mariana de Oliveira Lage ◽

...

Keyword(s):

Remote Sensing ◽

Aedes Aegypti ◽

Vector Control ◽

Land Surface ◽

Urban Areas ◽

Negative Binomial ◽

Control Strategies ◽

Winter Season ◽

Landsat 8 ◽

Thermal Features

AbstractIdentifying Aedes aegypti breeding hotspots in urban areas is crucial for the design of effective vector control strategies. Remote sensing techniques offer valuable tools for mapping habitat suitability. In this study, we evaluated the association between urban landscape, thermal features, and mosquito infestations. Entomological surveys were conducted between 2016 and 2019 in Vila Toninho, a neighborhood of São José do Rio Preto, São Paulo, Brazil, in which the numbers of adult female Ae. aegypti were recorded monthly and grouped by season for three years. We used data from 2016 to 2018 to build the model and data from summer of 2019 to validate it. WorldView-3 satellite images were used to extract land cover classes, and land surface temperature data were obtained using the Landsat-8 Thermal Infrared Sensor (TIRS). A multilevel negative binomial model was fitted to the data, which showed that the winter season has the greatest influence on decreases in mosquito abundance. Green areas and pavements were negatively associated, and a higher cover of asbestos roofs and exposed soil was positively associated with the presence of adult females. These features are related to socio-economic factors but also provide favorable breeding conditions for mosquitos. The application of remote sensing technologies has significant potential for optimizing vector control strategies, future mosquito suppression, and outbreak prediction.

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Maximizing public health protection with integrated vector control

American Journal of Public Health ◽

10.2105/ajph.91.3.497 ◽

2001 ◽

Vol 91 (3) ◽

pp. 497-498

Keyword(s):

Public Health ◽

Vector Control ◽

Health Protection ◽

Public Health Protection ◽

Integrated Vector Control

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Spatial modeling of dengue and socio-environmental indicators in the city of Rio de Janeiro, Brazil

Cadernos de Saúde Pública ◽

10.1590/s0102-311x2011000300019 ◽

2011 ◽

Vol 27 (3) ◽

pp. 591-602 ◽

Cited By ~ 13

Author(s):

Tatiana Rodrigues de Araujo Teixeira ◽

Oswaldo Gonçalves Cruz

Keyword(s):

Environmental Variables ◽

Rio De Janeiro ◽

Gini Index ◽

Control Strategies ◽

Time Lag ◽

Environmental Indicators ◽

Dengue Transmission ◽

Direct Association ◽

Conditional Autoregressive ◽

Dengue Control

This study analyzed the spatial distribution of dengue in Rio de Janeiro, Brazil, in 2006, and associations between the incidence per 100,000 inhabitants and socio-environmental variables. The study analyzed reported dengue cases among the city's inhabitants, rainfall, Breteau index (for Aedes aegypti and Aedes albopictus), Gini index, and social development index. We conducted mapping and used the global Moran index to measure the indicators' spatial autocorrelation, which was positive for all variables. The generalized linear model showed a direct association between dengue incidence and rainfall, one-month rainfall time lag, Gini index, and Breteau index for A. albopictus. The conditional autoregressive model (CAR) showed a direct association with rainfall for four months of the year, rain time lag in July, and Gini index in February. The results demonstrate the importance of socio-environmental variables in the dynamics of dengue transmission and the relevance for the development of dengue control strategies.

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Optimal Control of a Dengue-Dengvaxia Model: Comparison Between Vaccination and Vector Control

Computational and Mathematical Biophysics ◽

10.1515/cmb-2020-0124 ◽

2021 ◽

Vol 9 (1) ◽

pp. 198-212

Author(s):

Cheryl Q. Mentuda

Keyword(s):

Optimal Control ◽

Vector Control ◽

Basic Reproduction Number ◽

Human Population ◽

Model Comparison ◽

Reproduction Number ◽

Control Strategies ◽

Minimum Principle ◽

Transmitted Disease ◽

The Basic Reproduction Number

Abstract Dengue is the most common mosquito-borne viral infection transmitted disease. It is due to the four types of viruses (DENV-1, DENV-2, DENV-3, DENV-4), which transmit through the bite of infected Aedes aegypti and Aedes albopictus female mosquitoes during the daytime. The first globally commercialized vaccine is Dengvaxia, also known as the CYD-TDV vaccine, manufactured by Sanofi Pasteur. This paper presents a Ross-type epidemic model to describe the vaccine interaction between humans and mosquitoes using an entomological mosquito growth population and constant human population. After establishing the basic reproduction number ℛ0, we present three control strategies: vaccination, vector control, and the combination of vaccination and vector control. We use Pontryagin’s minimum principle to characterize optimal control and apply numerical simulations to determine which strategies best suit each compartment. Results show that vector control requires shorter time applications in minimizing mosquito populations. Whereas vaccinating the primary susceptible human population requires a shorter time compared to the secondary susceptible human.

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Public health response and lessons learned from the 2014 chikungunya epidemic in Grenada

Revista Panamericana de Salud Pública ◽

10.26633/rpsp.2017.57 ◽

2017 ◽

Vol 41 ◽

pp. 1 ◽

Cited By ~ 3

Author(s):

Martin S Forde ◽

Francis Martin ◽

George Mitchell ◽

Satesh Bidaisee

Keyword(s):

Health Care ◽

Vector Control ◽

Control Strategies ◽

Lessons Learned ◽

Epidemiological Surveillance ◽

Mosquito Vector ◽

Public Health Response ◽

Island State ◽

Health Response ◽

Multiple Challenges

In June 2014, the first cases of chikungunya virus (CHIKV) were diagnosed on the island of Carriacou, part of the tri-island state of Grenada. In the three months that followed, CHIKV spread rapidly, with conservative estimates of the population infected of at least 60%. Multiple challenges were encountered in the battle to manage the spread and impact of this high–attack rate virus, including 1) limited indigenous laboratory diagnostic capabilities; 2) an under-resourced health care system; 3) a skeptical general public, hesitant to accept facts about the origin and mode of transmission of the new virus; and 4) resistance to the vector control strategies used. Lessons learned from the outbreak included the need for 1) a robust and reliable epidemiological surveillance system; 2) effective strategies for communicating with the general population; 3) exploration of other methods of mosquito vector control; and 4) a careful review of all health care policies and protocols to ensure that effective, organized responses are triggered when an infectious outbreak occurs.

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Vector Control Based Rotating Speed Control Strategies in Aero Hydraulic Pump Test System

Journal of Mechanical Engineering ◽

10.3901/jme.2009.03.311 ◽

2009 ◽

Vol 45 (03) ◽

pp. 311 ◽

Cited By ~ 1

Author(s):

Wenjun MENG

Keyword(s):

Vector Control ◽

Control Strategies ◽

Speed Control ◽

Test System ◽

Hydraulic Pump ◽

Rotating Speed ◽

Pump Test

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Molecular Characterization of Culturable Aerobic Bacteria in the Midgut of Field-Caught Culex tritaeniorhynchus, Culex gelidus, and Mansonia annulifera Mosquitoes in the Gampaha District of Sri Lanka

BioMed Research International ◽

10.1155/2020/8732473 ◽

2020 ◽

Vol 2020 ◽

pp. 1-13

Author(s):

Nayana Gunathilaka ◽

Koshila Ranasinghe ◽

Deepika Amarasinghe ◽

Wasana Rodrigo ◽

Harendra Mallawarachchi ◽

...

Keyword(s):

Sri Lanka ◽

Vector Control ◽

Control Strategies ◽

Mosquito Species ◽

Diversity Indices ◽

Plate Count ◽

Adult Mosquito ◽

Relative Distribution ◽

Bacterial Isolates ◽

Culex Tritaeniorhynchus

Background. Larval and adult mosquito stages harbor different extracellular microbes exhibiting various functions in their digestive tract including host-parasite interactions. Midgut symbiotic bacteria can be genetically exploited to express molecules within the vectors, altering vector competency and potential for disease transmission. Therefore, identification of mosquito gut inhabiting microbiota is of ample importance before developing novel vector control strategies that involve modification of vectors. Method. Adult mosquitoes of Culex tritaeniorhynchus, Culex gelidus, and Mansonia annulifera were collected from selected Medical Officer of Health (MOH) areas in the Gampaha district of Sri Lanka. Midgut lysates of the field-caught non-blood-fed female mosquitoes were cultured in Plate Count Agar medium, and Prokaryotic 16S ribosomal RNA partial genes of the isolated bacteria colonies were amplified followed by DNA sequencing. Diversity indices were used to assess the diversity and richness of the bacterial isolates in three mosquito species. The distribution pattern of bacterial isolates between different mosquito species was assessed by Distance-Based Redundancy Analysis (dbRDA). Results. A total of 20 bacterial species (Staphylococcus pasteuri, Bacillus megaterium, Staphylococcus cohnii, Pantoea dispersa, Staphylococcus chromogenes, Bacillus aquimaris, Staphylococcus arlettae, Staphylococcus sciuri, Staphylococcus warneri, Moraxella osloensis, Enterobacter sp., Klebsiella michiganensis, Staphylococcus hominis, Staphylococcus saprophyticus, Streptomyces sp., Bacillus niacin, Cedecea neteri, Micrococcus luteus, Lysinibacillus sphaericus, and Bacillus licheniformis) were identified. All of these species belonged to three phyla, Proteobacteria, Firmicutes, and Actinobacteria, out of which phylum Firmicutes (71.1%) was the most prominent. The least number of species was recorded from Actinobacteria. The relative distribution of midgut microbes in different mosquito species differed significantly among mosquito species (Chi-square, χ2=486.091; df=36; P≤0.001). Midgut microbiota of Cx. tritaeniorhynchus and Cx. gelidus indicated a similarity of 21.51%, while Ma. annulifera shared a similarity of 6.92% with the cluster of above two species. The gut microbiota of Cx. tritaeniorhynchus was also significantly more diverse and more evenly distributed compared to Ma. annulifera. Simpson’s diversity, Margalef’s diversity, and Menhinick’s diversity indices were higher in Cx. gelidus. Of the recorded species, P. dispersa and strains of nonpathogenic species in Bacillaceae family (B. megaterium, B. niacini, B. licheniformis, and L. sphaericus) can be recommended as potential candidates for paratransgenesis. Conclusion. The relative distribution of midgut microbes in different mosquito species differed significantly among the three studied adult mosquito species. The present data strongly encourage further investigations to explore the potential usage of these microbes through paratransgenic approach for novel eco-friendly vector control strategies.

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