Dataset Information

Optimal management strategy of insecticide resistance under various insect life histories: Heterogeneous timing of selection and interpatch dispersal.

ABSTRACT: Although theoretical studies have shown that the mixture strategy, which uses multiple toxins simultaneously, can effectively delay the evolution of insecticide resistance, whether it is the optimal management strategy under different insect life histories and insecticide types remains unknown. To test the robustness of this management strategy over different life histories, we developed a series of simulation models that cover almost all the diploid insect types and have the same basic structure describing pest population dynamics and resistance evolution with discrete time steps. For each of two insecticidal toxins, independent one-locus two-allele autosomal inheritance of resistance was assumed. The simulations demonstrated the optimality of the mixture strategy either when insecticide efficacy was incomplete or when some part of the population disperses between patches before mating. The rotation strategy, which uses one insecticide on one pest generation and a different one on the next, did not differ from sequential usage in the time to resistance, except when dominance was low. It was the optimal strategy when insecticide efficacy was high and premating selection and dispersal occur.

SUBMITTER: Sudo M

PROVIDER: S-EPMC5775500 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Optimal management strategy of insecticide resistance under various insect life histories: Heterogeneous timing of selection and interpatch dispersal.

Sudo Masaaki M Takahashi Daisuke D Andow David A DA Suzuki Yoshito Y Yamanaka Takehiko T

Evolutionary applications 20171102 2

Although theoretical studies have shown that the mixture strategy, which uses multiple toxins simultaneously, can effectively delay the evolution of insecticide resistance, whether it is the optimal management strategy under different insect life histories and insecticide types remains unknown. To test the robustness of this management strategy over different life histories, we developed a series of simulation models that cover almost all the diploid insect types and have the same basic structur ...[more]

PMID: 29387161

Similar Datasets

Project description:BackgroundDengue infection is endemic in many regions throughout the world. While insecticide fogging targeting the vector mosquito Aedes aegypti is a major control measure against dengue epidemics, the impact of this method remains controversial. A previous mathematical simulation study indicated that insecticide fogging minimized cases when conducted soon after peak disease prevalence, although the impact was minimal, possibly because seasonality and population immunity were not considered. Periodic outbreak patterns are also highly influenced by seasonal climatic conditions. Thus, these factors are important considerations when assessing the effect of vector control against dengue. We used mathematical simulations to identify the appropriate timing of insecticide fogging, considering seasonal change of vector populations, and to evaluate its impact on reducing dengue cases with various levels of transmission intensity.Methodology/principal findingsWe created the Susceptible-Exposed-Infectious-Recovered (SEIR) model of dengue virus transmission. Mosquito lifespan was assumed to change seasonally and the optimal timing of insecticide fogging to minimize dengue incidence under various lengths of the wet season was investigated. We also assessed whether insecticide fogging was equally effective at higher and lower endemic levels by running simulations over a 500-year period with various transmission intensities to produce an endemic state. In contrast to the previous study, the optimal application of insecticide fogging was between the onset of the wet season and the prevalence peak. Although it has less impact in areas that have higher endemicity and longer wet seasons, insecticide fogging can prevent a considerable number of dengue cases if applied at the optimal time.Conclusions/significanceThe optimal timing of insecticide fogging and its impact on reducing dengue cases were greatly influenced by seasonality and the level of transmission intensity. We suggest that these factors should be considered when planning a control strategy against dengue vectors.

Project description:BACKGROUND:For pancreatic adenocarcinoma (PDAC), no studies have established any association between earlier treatment initiation and long-term outcomes. In addition, an optimal type of initial treatment for the localized disease remains ill-defined. METHODS:Patients in the National Cancer Database (2004-2015) with clinical stage I (CS-I) and II (CS-II) PDAC who underwent curative-intent resection were included. Optimal time from diagnosis-to-treatment including neoadjuvant chemotherapy, neoadjuvant chemoradiation, or upfront surgery was assessed. An optimal type of treatment was evaluated. The primary outcome was overall survival (OS). RESULTS:Among 29 167 patients, starting any treatment within 0 to 6 weeks was associated with improved median OS compared with 7 to 12 weeks (21.0 vs 20.1 months; P = .004). This persisted when accounting for sex, race, and Charlson-Deyo score (hazard ratio [HR], 0.94; P = 0.02) and on subset analysis for CS-I (23.5 vs 21.8 months; P = .04) and CS-II (19.4 vs 18.3 months; P = .03). Neoadjuvant chemotherapy was associated with improved OS compared with neoadjuvant chemoradiation (25.6 vs 22.7 months; P < .0001) or US (25.6 vs 20.1 months; P < .0001) even when accounting for sex, race, and Charlson-Deyo score (neoadjuvant chemoradiation: HR, 0.86; P < .001; US: HR, 0.79; P < .001). This improvement persisted in subset analysis with NC compared with neoadjuvant chemoradiation (CS-I: 28.6 vs 25.0 months; CS-II: 25.0 vs 22.9 months; both P < .0001) and to US (CS-I: 28.6 vs 22.9 months; CS-II: 24.7 vs 18.4 months; both P < .0001). On multivariable analysis for each CS-I/CS-II, NC remained associated with 20% improved survival compared with neoadjuvant chemoradiation or upfront surgery. CONCLUSIONS:For PDAC, initiation of therapy within 6 weeks from diagnosis is associated with improved survival, with neoadjuvant chemotherapy associated with the best survival compared with neoadjuvant chemoradiation or upfront surgery.

Dataset Information

Optimal management strategy of insecticide resistance under various insect life histories: Heterogeneous timing of selection and interpatch dispersal.

Publications

Optimal management strategy of insecticide resistance under various insect life histories: Heterogeneous timing of selection and interpatch dispersal.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets