scholarly journals Linking mosquito surveillance to dengue fever through Bayesian mechanistic modeling

2020 ◽  
Vol 14 (11) ◽  
pp. e0008868
Author(s):  
Clinton B. Leach ◽  
Jennifer A. Hoeting ◽  
Kim M. Pepin ◽  
Alvaro E. Eiras ◽  
Mevin B. Hooten ◽  
...  
Keyword(s):  
Human Disease ◽  
Mosquito Control ◽  
Disease Risk ◽  
Case Reports ◽  
Mechanistic Modeling ◽  
Adult Mosquito ◽  
Dengue Case ◽  
Modeling Framework ◽  
Mosquito Abundance ◽  
Mosquito Mortality

Our ability to effectively prevent the transmission of the dengue virus through targeted control of its vector, Aedes aegypti, depends critically on our understanding of the link between mosquito abundance and human disease risk. Mosquito and clinical surveillance data are widely collected, but linking them requires a modeling framework that accounts for the complex non-linear mechanisms involved in transmission. Most critical are the bottleneck in transmission imposed by mosquito lifespan relative to the virus’ extrinsic incubation period, and the dynamics of human immunity. We developed a differential equation model of dengue transmission and embedded it in a Bayesian hierarchical framework that allowed us to estimate latent time series of mosquito demographic rates from mosquito trap counts and dengue case reports from the city of Vitória, Brazil. We used the fitted model to explore how the timing of a pulse of adult mosquito control influences its effect on the human disease burden in the following year. We found that control was generally more effective when implemented in periods of relatively low mosquito mortality (when mosquito abundance was also generally low). In particular, control implemented in early September (week 34 of the year) produced the largest reduction in predicted human case reports over the following year. This highlights the potential long-term utility of broad, off-peak-season mosquito control in addition to existing, locally targeted within-season efforts. Further, uncertainty in the effectiveness of control interventions was driven largely by posterior variation in the average mosquito mortality rate (closely tied to total mosquito abundance) with lower mosquito mortality generating systems more vulnerable to control. Broadly, these correlations suggest that mosquito control is most effective in situations in which transmission is already limited by mosquito abundance.

scholarly journals Entomological Surveillance for Zika and Dengue Virus in Aedes Mosquitoes: Implications for Vector Control in Thailand

Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 442
Author(s):  
Nathamon Kosoltanapiwat ◽  
Jarinee Tongshoob ◽  
Preeraya Singkhaimuk ◽  
Chanyapat Nitatsukprasert ◽  
Silas A. Davidson ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Vector Control ◽  
Mosquito Control ◽  
Case Reports ◽  
Dengue Case ◽  
Prevention Measures ◽  
Entomological Surveillance ◽  
Vector Borne Diseases ◽  
Envelope Sequence ◽  
Surveillance Programs

Entomological surveillance for arthropod-borne viruses is vital for monitoring vector-borne diseases and informing vector control programs. In this study, we conducted entomological surveillance in Zika virus endemic areas. In Thailand, it is standard protocol to perform mosquito control within 24 h of a reported dengue case. Aedes females were collected within 72 h of case reports from villages with recent Zika–human cases in Kamphaeng Phet Province, Thailand in 2017 and 2018. Mosquitoes were bisected into head-thorax and abdomen and then screened for Zika (ZIKV) and dengue (DENV) viruses using real-time RT-PCR. ZIKV RNA was detected in three samples from two female Ae. aegypti (1.4%). A partial envelope sequence analysis revealed that the ZIKV sequences were the Asian lineage identical to sequences from ZIKV-infected cases reported in Thailand during 2016 and 2017. Dengue virus-1 (DENV-1) and dengue virus-4 (DENV-4) were found in four Ae. aegypti females (2.8%), and partial capsid sequences were nearly identical with DENV-1 and DENV-4 from Thai human cases reported in 2017. Findings in the current study demonstrate the importance of entomological surveillance programs to public health mosquito-borne disease prevention measures and control.

scholarly journals How disease risk awareness modulates transmission: coupling infectious disease models with behavioral dynamics

2021 ◽  
Author(s):  
Jaime Cascante-Vega ◽  
Samuel Torres-Florez ◽  
Juan Cordovez ◽  
Mauricio Santos-Vega
Keyword(s):  
Steady State ◽  
Disease Risk ◽  
Mechanistic Modeling ◽  
Transmission Dynamics ◽  
Epidemiological Models ◽  
Response Dynamics ◽  
Modeling Framework ◽  
Sis Model ◽  
Behavioral Dynamics ◽  
General Terms

Epidemiological models often assume that individuals do not change their behavior or that those aspects are implicitly incorporated in parameters in the models. Typically these assumption is included in the contact rate between infectious and susceptible individuals. For example models incorporate time variable contact rates to account for the effect of behavior or other interventions than in general terms reduce transmission. However, adaptive behaviors are expected to emerge and to play an important role in the transmission dynamics across populations. Here, we propose a theoretical framework to couple transmission dynamics with behavioral dynamics due to infection awareness. We first model the dynamics of social behavior by using a game theory framework. Then we coupled the model with an epidemiological model that captures the disease dynamics by assuming that individuals are more aware of that epidemiological state (i.e. fraction of infected individuals) and reduces their contacts. Our results from a mechanistic modeling framework show that as individuals increase their awareness the steady-state value of the final fraction of infected individuals in a susceptible-infected-susceptible (SIS) model decreases. We also extend our results to a spatial framework, incorporating a spatially-defined theoretical contact network (social network) and we made the awareness parameter dependent on a global or local contact structure. Our results show that even when individuals increase their awareness of the disease, the spatial structure itself defines the steady state solution of the system, in which more connected networks (networks with random or constant degree distributions) results in a population with no change in their behavior. Our work then shows that explicitly incorporating dynamics about the behavioral response dynamics might significantly change the predicted course of the epidemic and therefore highlights the importance of accounting for this source of variation in the epidemiological models.

scholarly journals Reducing West Nile Virus Risk Through Vector Management

2019 ◽  
Vol 56 (6) ◽  
pp. 1516-1521 ◽  
Author(s):  
Roger S Nasci ◽  
John-Paul Mutebi
Keyword(s):  
United States ◽  
West Nile Virus ◽  
Mosquito Control ◽  
Case Reports ◽  
The United States ◽  
Adult Mosquito ◽  
Economic Injury Level ◽  
Multiple Control ◽  
West Nile ◽  
Economic Injury

Abstract Over 50,000 human West Nile virus (WNV) (Flaviviridae: Flavivirus) clinical disease cases have been reported to the CDC during the 20 yr that the virus has been present in the United States. Despite the establishment and expansion of WNV-focused mosquito surveillance and control efforts and a renewed emphasis on applying integrated pest management (IPM) principles to WNV control, periodic local and regional WNV epidemics with case reports exceeding 2,000 cases per year have occurred during 13 of those 20 yr in the United States. In this article, we examine the scientific literature for evidence that mosquito control activities directed at either preventing WNV outbreaks or stopping those outbreaks once in progress reduce WNV human disease or have a measurable impact on entomological indicators of human WNV risk. We found that, despite a proliferation of research investigating larval and adult mosquito control effectiveness, few of these studies actually measure epidemiological outcomes or the entomological surrogates of WNV risk. Although many IPM principles (e.g., control decisions based on surveillance, use of multiple control methodologies appropriate for the ecosystem) have been implemented effectively, the use of action thresholds or meaningful public health outcome assessments have not been used routinely. Establishing thresholds for entomological indicators of human risk analogous to the economic injury level and economic thresholds utilized in crop IPM programs may result in more effective WNV prevention.

scholarly journals Efficacy of Petiveria Alliacea (Linneaus) leaf and root bark powder in the control of filariasis vector Culex Quinquefasciatus

2021 ◽  
Vol 82 (1) ◽  
Author(s):  
Michael Olarewaju Akintan ◽  
Joseph Onaolapo Akinneye ◽  
Oluwatosin Betty Ilelakinwa
Keyword(s):  
Synergistic Effect ◽  
Culex Quinquefasciatus ◽  
Mosquito Control ◽  
Exposure Period ◽  
Botanical Insecticides ◽  
Adult Mosquito ◽  
Root Bark ◽  
Plant Powders ◽  
Petiveria Alliacea ◽  
Feeding Activities

Abstract Background Mosquitoes are vectors of parasitic diseases such as malaria, lymphatic filariasis, yellow fever, and dengue fever among others. They are well known as public enemies for their noise nuisance, biting annoyance, sleeplessness, allergic reactions, and diseases transmission during the biting and feeding activities. This then necessitate the search for insecticides of plant origin which are bio-degradable, non-toxic, and readily available for man use. Result This study, evaluated the fumigant efficacy of the powder of P. alliacea to control the adult stage of Culex mosquito. Powder of Petiveria alliacea were administered at different dose of (1 g, 2 g, 3 g, 4 g, and 5 g), respectively. Result obtained shows the fumigant effect of the powder were effective with percentage mortality of 18.33–60.00% for the leaf powder and 23.30–71.60% for the root powder within 2 h post-treatment period (P < 0.05). The synergistic effect of the leaf and root powder was also investigated. The lethal dosage (LD50) of the leaf, root, and synergistic effect of leaf and root bark powder required to kill 50% of the adult Culex quinquefasciatus was 3.76 g, 2.86 g, and 2.63 g, respectively. However, 25.06 g, 15.25 g, and 12.94 g of the leaf, root, and leaf and root powder were required to kill 90% (LD90) after a 2-h exposure period. Conclusion These finding suggested P. alliacea powder could be a good source of insecticide which may be used for the production of biopesticides. The present findings have important implications in the practical control of adult mosquito by using botanical insecticides. These plant powders are easy to prepare, inexpensive, and safe for use in mosquito control.

Bionomics of Anopheles Arabiensis from Mamfene in KwaZulu-Natal (South Africa): An Area of High Malaria Transmission in the Province

2020 ◽  
Author(s):  
Rajendra Maharaj ◽  
Vishan Lakan ◽  
Kiash Maharaj
Keyword(s):  
South Africa ◽  
Vector Control ◽  
Anopheles Arabiensis ◽  
Mosquito Control ◽  
Sex Ratios ◽  
Adult Mosquito ◽  
Mosquito Vector ◽  
Larval Control ◽  
Kwazulu Natal ◽  
The Impact

Abstract Background: Although great strides have been made in controlling malaria, the disease is of significant public health importance. Historically, efforts to control the vector has concentrated on adult vector control targeting the female Anopheles mosquitoes. As there is now a focus on eliminating residual malaria from KwaZulu-Natal, new strategies are being investigated to increase the impact of malaria elimination strategies. Greater attention is now being given to larval control, as a complementary measure to indoor residual spraying. However, there is a large gap in knowledge of the bionomics of the larval stages of this mosquito vector of malaria in South Africa. In order to focus on both larval and adult mosquito control methods, larval development and the reproductive stages of the vector were investigated since these variables influences our ability to impact mosquito populations through larval control. This study was therefore conducted to determine the peak eruption times and the emergent sex ratios, as well as the peak egg oviposition time in order to attack the mosquito when it is at its most vulnerable and when control interventions will have the most impact.Results: Oviposition studies showed two peaks corresponding with late evening and again just before dawn. Most eggs were also laid in the first half of the night (18h00 – midnight). Most mosquitoes erupted just after sunset and the sex ratios showed that twice as many females as males emerged. Females readily took a bloodmeal after oviposition or just after erupting. Hatch rate to viable first instar larvae was 74.5%.Conclusions: The results of this study have provided information as to when interventions would be most effective in controlling mosquito populations and have provided information that highlights the value of larval control as a complementary measure to adult mosquito control. The most vulnerable stages of the female Anopheles arabiensis are when they have just emerged or when they have just oviposited. Vector control strategies should be designed to target these vulnerable stages at the breeding sites in order to have maximum impact.

scholarly journals A mechanistic modeling framework for gas-phase adsorption kinetics and fixed-bed transport

AIChE Journal ◽  
2017 ◽  
Vol 63 (11) ◽  
pp. 5029-5043 ◽  
Author(s):  
Austin P. Ladshaw ◽  
Sotira Yiacoumi ◽  
Ronghong Lin ◽  
Yue Nan ◽  
Lawrence L. Tavlarides ◽  
...  
Keyword(s):  
Gas Phase ◽  
Adsorption Kinetics ◽  
Fixed Bed ◽  
Mechanistic Modeling ◽  
Modeling Framework ◽  
Gas Phase Adsorption

scholarly journals A practical guide to mechanistic systems modeling in biology using a logic-based approach

2020 ◽  
Author(s):  
Anna Niarakis ◽  
Tomáš Helikar
Keyword(s):  
Computational Modeling ◽  
Computational Models ◽  
Regulatory System ◽  
Mechanistic Modeling ◽  
Lac Operon ◽  
Modeling Framework ◽  
Validation Criteria ◽  
Hands On ◽  
Modeling Software ◽  
Logical Modeling

Abstract Mechanistic computational models enable the study of regulatory mechanisms implicated in various biological processes. These models provide a means to analyze the dynamics of the systems they describe, and to study and interrogate their properties, and provide insights about the emerging behavior of the system in the presence of single or combined perturbations. Aimed at those who are new to computational modeling, we present here a practical hands-on protocol breaking down the process of mechanistic modeling of biological systems in a succession of precise steps. The protocol provides a framework that includes defining the model scope, choosing validation criteria, selecting the appropriate modeling approach, constructing a model and simulating the model. To ensure broad accessibility of the protocol, we use a logical modeling framework, which presents a lower mathematical barrier of entry, and two easy-to-use and popular modeling software tools: Cell Collective and GINsim. The complete modeling workflow is applied to a well-studied and familiar biological process—the lac operon regulatory system. The protocol can be completed by users with little to no prior computational modeling experience approximately within 3 h.

Impact of adult mosquito control on dengue prevalence in a multi-patch setting: A case study in Kolkata (2014–2015)

2019 ◽  
Vol 478 ◽  
pp. 139-152 ◽  
Author(s):  
Abhishek Senapati ◽  
Tridip Sardar ◽  
Krishnendra Sankar Ganguly ◽  
Krishna Sankar Ganguly ◽  
Asis Kumar Chattopadhyay ◽  
...  
Keyword(s):  
Mosquito Control ◽  
Adult Mosquito

Limited impacts of truck-based ultra-low-volume applications of mosquito adulticides on mortality in honey bees (Apis mellifera)

2017 ◽  
Vol 107 (6) ◽  
pp. 724-733 ◽  
Author(s):  
F.D. Rinkevich ◽  
J.W. Margotta ◽  
V. Pokhrel ◽  
T.W. Walker ◽  
R.H. Vaeth ◽  
...  
Keyword(s):  
Apis Mellifera ◽  
Honey Bee ◽  
Mosquito Control ◽  
Application Rate ◽  
High Rate ◽  
Application Rates ◽  
Mosquito Mortality ◽  
Low Volume ◽  
High Label ◽  
Low Rate

AbstractAdulticides applied against mosquitoes can reduce vector populations during times of high arbovirus transmission. However, impacts of these insecticides on pollinators and other non-target organisms are of concern to mosquito control professionals, beekeepers and others. We evaluated mortality of Culex quinquefasciatus and Apis mellifera when caged insects were exposed to low and high label rates of four common adulticides (Aqua-Pursuit™ [permethrin], Duet® [prallethrin + sumithrin], Fyfanon® [malathion] and Scourge® [resmethrin]) at six distances up to 91.4 m from a truck-mounted ultra-low-volume sprayer. Honey bee mortality was both absolutely low (<10%) and low relative to mosquito mortality for most products, distances, and application rates. Exceptions were at the high rate of Fyfanon (honey bee mortality of 22–100% at distances ≤61 m) and the low rate of Scourge (mortality <10% for both insects). The greatest ratios of mosquito-to-honey bee mortality were found for the low rate of Fyfanon (30× greater) and the high rate of Duet (50× greater). Aqua-Pursuit and Fyfanon tended to increase mortality of both species at closer distances and at higher application rate; this was related to increased number and size of spray droplets. Wind speed and temperature had inconsistent effects on mortality of mosquitoes only. In this bioassay designed to have insects directly intercept insecticide droplets, mosquito adulticides applied at low rates and at >61 m had limited impacts on honey bee mortality while providing effective mosquito control.

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