scholarly journals Controlling COVID-19 Outbreaks with Financial Incentives

2021 ◽  
Vol 18 (2) ◽  
pp. 724
Author(s):  
Chaeyoung Lee ◽  
Soobin Kwak ◽  
Junseok Kim
Keyword(s):  
Disease Transmission ◽  
Financial Incentives ◽  
Transmission Rate ◽  
Economic Losses ◽  
Total Cost ◽  
Infected People ◽  
Infected Population ◽  
Estimated Parameters ◽  
Two Parameters ◽  
Termination Time

In this paper, we consider controlling coronavirus disease 2019 (COVID-19) outbreaks with financial incentives. We use the recently developed susceptible-unidentified infected-confirmed (SUC) epidemic model. The unidentified infected population is defined as the infected people who are not yet identified and isolated and can spread the disease to susceptible individuals. It is important to quickly identify and isolate infected people among the unidentified infected population to prevent the infectious disease from spreading. Considering financial incentives as a strategy to control the spread of disease, we predict the effect of the strategy through a mathematical model. Although incentive costs are required, the duration of the disease can be shortened. First, we estimate the unidentified infected cases of COVID-19 in South Korea using the SUC model, and compute two parameters such as the disease transmission rate and the inverse of the average time for confirming infected individuals. We assume that when financial incentives are provided, there are changes in the proportion of confirmed patients out of unidentified infected people in the SUC model. We evaluate the numbers of confirmed and unidentified infected cases with respect to one parameter while fixing the other estimated parameters. We investigate the effect of the incentives on the termination time of the spread of the disease. The larger the incentive budget is, the faster the epidemic will end. Therefore, financial incentives can have the advantage of reducing the total cost required to prevent the spread of the disease, treat confirmed patients, and recover overall economic losses.

scholarly journals Modeling the transmission dynamics of tuberculosis in Khyber Pakhtunkhwa Pakistan

2019 ◽  
Vol 11 (6) ◽  
pp. 168781401985483 ◽  
Author(s):  
Muhammad Altaf Khan ◽  
Manzoor Ahmad ◽  
Saif Ullah ◽  
Muhammad Farooq ◽  
Taza Gul
Keyword(s):  
Sensitivity Analysis ◽  
Disease Transmission ◽  
Transmission Rate ◽  
Model Parameters ◽  
Bacterial Disease ◽  
Treatment Rate ◽  
Khyber Pakhtunkhwa ◽  
Infected People ◽  
Tuberculosis Transmission ◽  
Number Formula

This article addresses the dynamics of the bacterial disease tuberculosis in Khyber Pakhtunkhwa, Pakistan, through a mathematical model. In this work, the latent compartment is divided into slow and fast kinds of progresses. The model is parameterized based on the reported tuberculosis-infected cases in Khyber Pakhtunkhwa for the period 2002–2017. We obtain the basic reproduction number [Formula: see text] of the model using the next-generation method. The estimated value of [Formula: see text] for the given period is approximately 1.38. Furthermore, it is shown that the model has two types of equilibria: disease-free and endemic equilibriums. The global stability analysis of the model equilibria is shown via Lyapunov functions. We also perform the sensitivity analysis of [Formula: see text] and present their corresponding graphical results to examine the relative importance of various model parameters to tuberculosis transmission and prevalence. Finally, some numerical simulations are done for the estimated parameters and the key parameters effects are considered on the curtailing tuberculosis disease. From the numerical results and model sensitivity analysis, it is found that the spread of tuberculosis can be minimized by increasing the treatment rate [Formula: see text] of infected people and decreasing the effective disease transmission rate [Formula: see text] and the rate [Formula: see text] at which the individuals leave treated class reenter infected classes.

scholarly journals Estimating asymptomatic, undetected and total cases for the COVID-19 outbreak in Wuhan: a mathematical modeling study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xi Huo ◽  
Jing Chen ◽  
Shigui Ruan
Keyword(s):  
Disease Transmission ◽  
Large Scale ◽  
Transmission Rate ◽  
Control Strategies ◽  
Herd Immunity ◽  
Antibody Prevalence ◽  
Screening Process ◽  
Vaccination Programs ◽  
Prevalence Level ◽  
The Impact

Abstract Background The COVID-19 outbreak in Wuhan started in December 2019 and was under control by the end of March 2020 with a total of 50,006 confirmed cases by the implementation of a series of nonpharmaceutical interventions (NPIs) including unprecedented lockdown of the city. This study analyzes the complete outbreak data from Wuhan, assesses the impact of these public health interventions, and estimates the asymptomatic, undetected and total cases for the COVID-19 outbreak in Wuhan. Methods By taking different stages of the outbreak into account, we developed a time-dependent compartmental model to describe the dynamics of disease transmission and case detection and reporting. Model coefficients were parameterized by using the reported cases and following key events and escalated control strategies. Then the model was used to calibrate the complete outbreak data by using the Monte Carlo Markov Chain (MCMC) method. Finally we used the model to estimate asymptomatic and undetected cases and approximate the overall antibody prevalence level. Results We found that the transmission rate between Jan 24 and Feb 1, 2020, was twice as large as that before the lockdown on Jan 23 and 67.6% (95% CI [0.584,0.759]) of detectable infections occurred during this period. Based on the reported estimates that around 20% of infections were asymptomatic and their transmission ability was about 70% of symptomatic ones, we estimated that there were about 14,448 asymptomatic and undetected cases (95% CI [12,364,23,254]), which yields an estimate of a total of 64,454 infected cases (95% CI [62,370,73,260]), and the overall antibody prevalence level in the population of Wuhan was 0.745% (95% CI [0.693%,0.814%]) by March 31, 2020. Conclusions We conclude that the control of the COVID-19 outbreak in Wuhan was achieved via the enforcement of a combination of multiple NPIs: the lockdown on Jan 23, the stay-at-home order on Feb 2, the massive isolation of all symptomatic individuals via newly constructed special shelter hospitals on Feb 6, and the large scale screening process on Feb 18. Our results indicate that the population in Wuhan is far away from establishing herd immunity and provide insights for other affected countries and regions in designing control strategies and planing vaccination programs.

scholarly journals The effects of flooding and weather conditions on leptospirosis transmission in Thailand

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sudarat Chadsuthi ◽  
Karine Chalvet-Monfray ◽  
Anuwat Wiratsudakul ◽  
Charin Modchang
Keyword(s):  
Sensitivity Analysis ◽  
Public Education ◽  
Mathematical Models ◽  
Disease Transmission ◽  
Transmission Rate ◽  
Weather Conditions ◽  
Transmission Dynamics ◽  
Multiplication Rate ◽  
High Degree ◽  
Transmission Models

AbstractThe epidemic of leptospirosis in humans occurs annually in Thailand. In this study, we have developed mathematical models to investigate transmission dynamics between humans, animals, and a contaminated environment. We compared different leptospire transmission models involving flooding and weather conditions, shedding and multiplication rate in a contaminated environment. We found that the model in which the transmission rate depends on both flooding and temperature, best-fits the reported human data on leptospirosis in Thailand. Our results indicate that flooding strongly contributes to disease transmission, where a high degree of flooding leads to a higher number of infected individuals. Sensitivity analysis showed that the transmission rate of leptospires from a contaminated environment was the most important parameter for the total number of human cases. Our results suggest that public education should target people who work in contaminated environments to prevent Leptospira infections.

scholarly journals Mother-child transmission of Chagas disease: could coinfection with human immunodeficiency virus increase the risk?

2009 ◽  
Vol 42 (2) ◽  
pp. 107-109 ◽  
Author(s):  
Pablo Gustavo Scapellato ◽  
Edgardo Gabriel Bottaro ◽  
María Teresa Rodríguez-Brieschke
Keyword(s):  
Human Immunodeficiency Virus ◽  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Vertical Transmission ◽  
Disease Transmission ◽  
Transmission Rate ◽  
Buffy Coat ◽  
Child Transmission ◽  
Serological Tests ◽  
Immunodeficiency Virus

A study was conducted on all newborns from mothers with Chagas disease who were attended at Hospital Donación F. Santojanni between January 1, 2001, and August 31, 2007. Each child was investigated for the presence of Trypanosoma cruzi parasitemia through direct examination of blood under the microscope using the buffy coat method on three occasions during the first six months of life. Serological tests were then performed. Ninety-four children born to mothers infected with Trypanosoma cruzi were attended over the study period. Three of these children were born to mothers coinfected with the human immunodeficiency virus. Vertical transmission of Chagas disease was diagnosed in 13 children, in all cases by identifying parasitemia. The overall Chagas disease transmission rate was 13.8% (13/94). It was 100% (3/3) among the children born to mothers with HIV infection and 10.9% (10/91) among children born to mothers without HIV [Difference = 0.89; CI95 = 0.82-0.95; p = 0.0021]. We concluded that coinfection with HIV could increase the risk of vertical transmission of Chagas disease.

scholarly journals Modeling the impact of school reopening and contact tracing strategies on Covid-19 dynamics in different epidemiologic settings in Brazil

2021 ◽  
Author(s):  
Marcelo Eduardo Borges ◽  
Leonardo Souto Ferreira ◽  
Silas Poloni ◽  
Ângela Maria Bagattini ◽  
Caroline Franco ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Transmission Rate ◽  
Disease Incidence ◽  
Demographic Data ◽  
School Closure ◽  
Mitigation Measures ◽  
Contact Tracing ◽  
School Closures ◽  
Infection Transmission ◽  
The Impact

Among the various non–pharmaceutical interventions implemented in response to the Covid–19 pandemic during 2020, school closures have been in place in several countries to reduce infection transmission. Nonetheless, the significant short and long–term impacts of prolonged suspension of in–person classes is a major concern. There is still considerable debate around the best timing for school closure and reopening, its impact on the dynamics of disease transmission, and its effectiveness when considered in association with other mitigation measures. Despite the erratic implementation of mitigation measures in Brazil, school closures were among the first measures taken early in the pandemic in most of the 27 states in the country. Further, Brazil delayed the reopening of schools and stands among the countries in which schools remained closed for the most prolonged period in 2020. To assess the impact of school reopening and the effect of contact tracing strategies in rates of Covid–19 cases and deaths, we model the epidemiological dynamics of disease transmission in 3 large urban centers in Brazil under different epidemiological contexts. We implement an extended SEIR model stratified by age and considering contact networks in different settings – school, home, work, and elsewhere, in which the infection transmission rate is affected by various intervention measures. After fitting epidemiological and demographic data, we simulate scenarios with increasing school transmission due to school reopening. Our model shows that reopening schools results in a non–linear increase of reported Covid-19 cases and deaths, which is highly dependent on infection and disease incidence at the time of reopening. While low rates of within[&ndash]school transmission resulted in small effects on disease incidence (cases/100,000 pop), intermediate or high rates can severely impact disease trends resulting in escalating rates of new cases even if other interventions remain unchanged. When contact tracing and quarantining are restricted to school and home settings, a large number of daily tests is required to produce significant effects of reducing the total number of hospitalizations and deaths. Our results suggest that policymakers should carefully consider the epidemiological context and timing regarding the implementation of school closure and return of in-person school activities. Also, although contact tracing strategies are essential to prevent new infections and outbreaks within school environments, our data suggest that they are alone not sufficient to avoid significant impacts on community transmission in the context of school reopening in settings with high and sustained transmission rates.

scholarly journals Modeling quarantine during epidemics and mass-testing using drones

2020 ◽  
Author(s):  
Leonid Sedov ◽  
Alexander Krasnochub ◽  
Valentin Polishchuk
Keyword(s):  
Differential Equations ◽  
Metropolitan Area ◽  
Extended Model ◽  
Epidemic Spread ◽  
Infected People ◽  
Peak Number ◽  
Infected Population ◽  
Sir Epidemic ◽  
Spread Model ◽  
Over Time

We extend the classical SIR epidemic spread model by introducing the “quarantined” compartment. We solve (numerically) the differential equations that govern the extended model and quantify how quarantining “flattens the curve” for the proportion of infected population over time. Furthermore, we explore the potential of using drones to deliver tests, enabling mass-testing for the infection; we give a method to estimate the drone fleet needed to deliver the tests in a metropolitan area. Application of our models to COVID-19 spread in Sweden shows how the proposed methods could substantially decrease the peak number of infected people, almost without increasing the duration of the epidemic.

Disease in fisheries and aquaculture

2020 ◽  
pp. 183-210
Author(s):  
Donald C. Behringer ◽  
Chelsea L. Wood ◽  
Martin Krkošek ◽  
David Bushek
Keyword(s):  
Human Health ◽  
Wild Species ◽  
Disease Transmission ◽  
Economic Losses ◽  
Nutrient Quality ◽  
Species Management ◽  
Negative Impacts ◽  
Management Approaches ◽  
Opening Up

Infectious marine diseases have profound impacts on fisheries and aquaculture through their effects on growth, fecundity, mortality, and marketability. Economic losses have motivated research to minimize the negative impacts of disease on these industries. However, this relationship is reciprocal, as fishing and aquaculture can shape disease transmission. The effects of fisheries and aquaculture on disease are scale dependent, with different outcomes at the population, metapopulation, community, and ecosystem levels. Management approaches are limited in fisheries, and intense in aquaculture, sometimes with undesirable impacts on wild species. Management needs can be particularly intense in hatcheries, where stocks are sensitive and kept at high densities. Increased interest in microbiome–disease interactions are opening up new opportunities to manage marine diseases in aquaculture. Solutions for marine diseases in fisheries and aquaculture may ultimately improve human health by reducing exposure to pathogens and increasing nutrient quality, but could negatively impact human health through exposure to antibiotics and other chemicals used to treat parasites.

Identification of Multiple Fault Parameters in a Rigid-Rotor and Flexible-Bearing-Coupling System: An Experimental Investigation

2013 ◽  
Author(s):  
Mohit Lal ◽  
Rajiv Tiwari
Keyword(s):  
Economic Losses ◽  
Identification Algorithm ◽  
Rigid Rotor ◽  
Human Beings ◽  
Multiple Fault ◽  
Rotating Machine ◽  
Estimated Parameters ◽  
Coupling System ◽  
Fault Parameters ◽  
Coupling Dynamic

Rotating machineries are very common and widely used in the modern industrial world. A breakdown of the rotating machine may result in economic losses and even worse, in the damage of human beings. So it needs accurate and reliable prediction of its dynamic characteristic. The multiple fault identification algorithm developed in [1] identifies the bearing and coupling dynamic parameters along with residual unbalances in a rigid-rotor and flexible-bearing-coupling system has been validated experimentally in the present article. An indigenously developed test rig was used for the experimentation. After estimating multiple fault parameters the accuracy of estimated parameters has been checked by checking the consistency of the estimated parameters and by performing the standard impact test. It has been observed that with more number of measurements consistencies of the estimated parameters are very good.

Biocontrol Potential of Trichoderma and Bacillus Species on Fusarium oxysporum f. sp vasinfectum

2019 ◽  
pp. 1-11
Author(s):  
Otília Ricardo De Farias ◽  
Luciana Cordeiro De Nascimento ◽  
José Manoel Ferreira de Lima Cruz ◽  
Hiago Antônio Oliveira Silva ◽  
Mônica Danielly de Mello Oliveira ◽  
...  
Keyword(s):  
Gossypium Hirsutum ◽  
Fusarium Oxysporum ◽  
Disease Transmission ◽  
Transmission Rate ◽  
Good Alternative ◽  
Bacillus Species ◽  
Trichoderma Spp ◽  
Cotton Seeds ◽  
Biocontrol Potential ◽  
Preventive Methods

Fusarium wilt, caused by Fusarium oxysporum f. sp. vasinfectum, is one of the major diseases of cotton. Preventive methods to manage this disease should be adopted what includes the seed treatment with biocontrol agents as a good alternative. This work aimed to evaluate the efficiency of biological products based on Trichoderma spp. and Bacillus subtilis in the control of Fusarium oxysporum f. sp. vasinfectum (Fov) applied in seeds and seedlings of cotton. The experiment was carried out at the Laboratório de Fitopatologia of the Centro de Ciências Agrárias, of the Universidade Federal de Paraíba (CCA-UFPB), located in the city of Areia, Paraíba - Brazil. The disease transmission of the seeds to the seedlings was evaluated. After the transmission test, cotton seeds of the variety Mocó (Gossypium hirsutum var. Marie-gallante (Watt) Hutch.), BRS 286 and Topázio cultivar (Gossypium hirsutum L.) were submitted to the treatments T1 - Control, T2 - Trichodel® (0,5 mL); T3-Trichodel® (1.0 mL); T4-Trichodel® (1.5 mL); T5-Trichodel® (2.0 mL); T6-Bactel® (2.0 mL); T7-Bactel® (2.5 mL); T8-Bactel® (3.0 mL); T9-Bactel® (3.5 mL) diluted in 100 mL SDW; T10 - Fungicide Captana (240 g / 100 kg of seeds) and inoculated with Fov. The pathogen incidence of the seeds was evaluated seven days after the inoculation (DAI). To evaluate the biological control of Fov in the seedlings, the treated seeds were submitted to the following inoculation methods: 1 - inoculation of the substrate with a pathogen conidia suspension; 2 - immersion of the seeds in the conidia suspension and 3 - direct contact of the seeds with the pathogen mycelium. Twenty-one DAI the disease severity and percentage of seedlings with vascular darkening were evaluated. It was observed a transmission rate of 64.0 to 89.0% of the seeds to the seedlings. Trichodel® reduced the incidence and severity of Fov in the cotton seedlings and was the most efficient product.

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