scholarly journals Evaluating the burden of COVID-19 on hospital resources in Bahia, Brazil: A modelling-based analysis of 14.8 million individuals

2020 ◽  
Author(s):  
Juliane Fonseca Oliveira ◽  
Daniel C. P. Jorge ◽  
Rafael V. Veiga ◽  
Moreno S. Rodrigues ◽  
Matheus F. Torquato ◽  
...  
Keyword(s):  
Transmission Rate ◽  
Health Resources ◽  
Compartment Model ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Model Parameters ◽  
Resource Setting ◽  
Asymptomatic Individuals ◽  
The One ◽  
The Impact

Here we present a general compartment model with a time-varying transmission rate to describe the dynamics of the COVID-19 epidemic, parameterized with the demographics of Bahia, a state in northeast Brazil. The dynamics of the model are influenced by the number of asymptomatic cases, hospitalization requirements and mortality due to the disease. A locally-informed model was determined using actual hospitalization records. Together with cases and casualty data, optimized estimates for model parameters were obtained within a metaheuristic framework based on Particle Swarm Optimization. Our strategy is supported by a statistical sensitivity analysis on the model parameters, adequate to properly account for the simulated scenarios. First, we evaluated the effect of previously enforced interventions on the transmission rate. Then, we studied its effects on the number of deaths as well as hospitalization requirements, considering the state as a whole. Special attention is given to the impact of asymptomatic individuals on the dynamic of COVID-19 transmission, as these were estimated to contribute to a 68% increase in the basic reproductive number. Finally, we delineated scenarios that can set guides to protect the health care system, particularly by keeping demand below total bed occupancy. Our results underscore the challenges related to maintaining a fully capable health infrastructure during the ongoing COVID-19 pandemic, specially in a low-resource setting such as the one focused in this work. The evidences produced by our modelling-based analysis show that decreasing the transmission rate is paramount to success in maintaining health resources availability, but that current local efforts, leading to a 38% decrease in the transmission rate, are still insufficient to prevent its collapse at peak demand. Carefully planned and timely applied interventions, that result in stark decreases in transmission rate, were found to be the most effective in preventing hospital bed shortages for the longest periods.

scholarly journals The impact of the COVID-19 pandemic on rabies reemergence in Latin America: the case of Arequipa, Peru

2020 ◽  
Author(s):  
Brinkley Raynor ◽  
Elvis W. Díaz ◽  
Julianna Shinnick ◽  
Edith Zegarra ◽  
Ynes Monroy ◽  
...  
Keyword(s):  
Latin America ◽  
Compartment Model ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Human Rabies ◽  
Innovative Strategies ◽  
Public Health Departments ◽  
Canine Rabies ◽  
Vaccination Campaigns ◽  
The Impact

Over the past decades, there has been tremendous progress towards eliminating canine rabies in Latin America. Major components of rabies prevention programs in Latin America leading to these successes have been constant and intense surveillance for rabid dogs and uninterrupted yearly mass dog vaccination campaigns. However, vital measures to control COVID-19 in Latin America have had the negative trade-off of jeopardizing these rabies elimination and prevention activities. In this paper, we aimed to assess the effect of interrupting canine rabies surveillance and mass dog vaccination campaigns on rabies trends. We built a deterministic compartment model of dog rabies dynamics parameterized for conditions found in Arequipa, Peru, where there is an ongoing dog rabies epidemic. Our model suggests that a decrease in canine vaccination coverage as well as decreased surveillance leading to an increased length of survival of infected dogs could lead to a sharp rise in canine rabies and, subsequently, human rabies risk. We examined our results over the best estimate of the basic reproductive number in Arequipa (R0 = 1.44) and a range of plausible values for R0 (1.36 - 2). The rising trend was consistent. It is very possible that COVID-19 will continue to challenge our public health departments in the short- and medium-term. Innovative strategies to conduct dog vaccination and rabies surveillance during these trying times should be considered to safeguard the achievements made in Latin America towards the elimination of dog-mediated human rabies.

ADAPTIVE DYNAMIC MODELLING OF HIV/AIDS EPIDEMIC USING EXTENDED KALMAN FILTER

1995 ◽  
Vol 03 (03) ◽  
pp. 759-768 ◽  
Author(s):  
B. CAZELLES ◽  
N. P. CHAU
Keyword(s):  
Kalman Filter ◽  
Transmission Rate ◽  
Dynamic Modelling ◽  
Compartment Model ◽  
Recursive Estimation ◽  
Model Parameters ◽  
Aids Epidemic ◽  
Intervention Measures ◽  
Asymptomatic Individuals ◽  
Hiv Aids

A simple compartment model was used to describe the observed HIV/AIDS epidemic in the homo/bisexual male community in Paris (France). In the first step, the model was fitted to the available data, using least squares procedures. The fitting of the model to subsets of the data could perfectly account for the observations, but did not afford a coherent estimation of the model parameters, and was unable to predict the actual development of the disease. These difficulties might result from the fact that many factors have modified the course of the HIV/AIDS epidemic in the recent years. So, a recursive estimation technique known as the Kalman filter has been used. The Kalman filter accounts for stochastic fluctuations both in the model and in the data, and enables to assess the possible progressive adaptation of the model parameters suggested by the new observations. Our study disclosed a noticeable change of some parameters of important epidemiological significance (average transmission rate and mean incubation rate) around the year 1988, most probably due to intervention measures like prevention and/or gradual introduction of early treatment for infected but asymptomatic individuals.

scholarly journals Transmission dynamics and control strategies of COVID-19: a modelling study

2021 ◽  
Vol 102 (2) ◽  
pp. 92-105
Author(s):  
U.T. Mustapha ◽  
◽  
E. Hincal ◽  
A. Yusuf ◽  
S. Qureshi ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Recovery Rate ◽  
Transmission Rate ◽  
Face Mask ◽  
Basic Reproductive Number ◽  
Effective Control ◽  
Reproductive Number ◽  
Model Parameters ◽  
Susceptible Population ◽  
Social Distancing

In this paper a mathematical model is proposed, which incorporates quarantine and hospitalization to assess the community impact of social distancing and face mask among the susceptible population. The model parameters are estimated and fitted to the model with the use of laboratory confirmed COVID-19 cases in Turkey from March 11 to October 10, 2020. The partial rank correlation coefficient is employed to perform sensitivity analysis of the model, with basic reproduction number and infection attack rate as response functions. Results from the sensitivity analysis reveal that the most essential parameters for effective control of COVID-19 infection are recovery rate from quarantine individuals (δ1), recovery rate from hospitalized individuals (δ4), and transmission rate (β). Some simulation results are obtained with the aid of mesh plots with respect to the basic reproductive number as a function of two different biological parameters randomly chosen from the model. Finally, numerical simulations on the dynamics of the model highlighted that infections from the compartments of each state variables decreases with time which causes an increase in susceptible individuals. This implies that avoiding contact with infected individuals by means of adequate awareness of social distancing and wearing face mask are vital to prevent or reduce the spread of COVID-19 infection.

scholarly journals Pesticide application, educational treatment and infectious respiratory diseases: A mechanistic model with two impulsive controls

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243048
Author(s):  
Juan Pablo Gutiérrez-Jara ◽  
Fernando Córdova-Lepe ◽  
María Teresa Muñoz-Quezada ◽  
Gerardo Chowell
Keyword(s):  
Respiratory Disease ◽  
Disease Transmission ◽  
Pesticide Exposure ◽  
Transmission Rate ◽  
Toxic Substance ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Pesticide Use ◽  
Educational Treatment ◽  
The Impact

In this paper, we develop and analyze an SIS-type epidemiological-mathematical model of the interaction between pesticide use and infectious respiratory disease transmission for investigating the impact of pesticide intoxication on the spread of these types of diseases. We further investigate the role of educational treatment for appropriate pesticide use on the transmission dynamics. Two impulsive control events are proposed: pesticide use and educational treatment. From the proposed model, it was obtained that the rate of forgetfulness towards educational treatment is a determining factor for the reduction of intoxicated people, as well as for the reduction of costs associated with educational interventions. To get reduced intoxications, the population’s fraction to which is necessary to apply the educational treatment depends on its individual effectiveness level and the educational treatments’ forgetfulness rate. In addition, the turnover of agricultural workers plays a fundamental role in the dynamics of agrotoxic use, particularly in the application of educational treatment. For illustration, a flu-like disease with a basic reproductive number below the epidemic threshold of 1.0 is shown can acquire epidemic potential in a population at risk of pesticide exposure. Hence, our findings suggest that educational treatment targeting pesticide exposure is an effective tool to reduce the transmission rate of an infectious respiratory disease in a population exposed to the toxic substance.

scholarly journals Assessing the Impact of Prophylactic Vaccines on HPV Prevalence

2019 ◽  
Vol 20 (2) ◽  
pp. 305
Author(s):  
F. Azevedo ◽  
L. Esteva ◽  
Claudia P. Ferreira
Keyword(s):  
Vaccine Coverage ◽  
Transmission Rate ◽  
Geometric Mean ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Asymptotically Stable ◽  
Globally Asymptotically Stable ◽  
Health Politics ◽  
Vaccination Strategies ◽  
The Impact

A mathematical model considering female and male individuals is proposed to evaluate vaccination strategies applied to control of HPV transmission in human population. The basic reproductive number of the disease, $R_0$, is given by the geometric mean of the basic reproductive number of female and male populations. The model has a globally asymptotically stable disease-free equilibrium whenever $R_0 <1$. Furthermore, it has an unique endemic state when $R_0$ exceeds unity which is globally asymptotically stable. Numerical simulations were done to compare several different vaccination schedules. The results showed that the vaccination strategies that do not include vaccination of men can only control the disease if more than 90\% of women are vaccinated. The sensitivity analysis indicated that the relevant parameters to control HPV transmission, in order of importance, are vaccine efficacy times the fraction of population that is vaccinated, disease recovery-rate, and disease transmission rate. Therefore, health politics that promoting the increase of vaccine coverage, and screening for the disease in both population can improve disease control.

SE2IR Invest Market Rumor Spreading Model Considering Hesitating Mechanism

2019 ◽  
Vol 7 (1) ◽  
pp. 54-69 ◽  
Author(s):  
Hongxing Yao ◽  
Xiangyang Gao
Keyword(s):  
Mean Field ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Field Equations ◽  
Rumor Spreading ◽  
Immunization Strategy ◽  
Scale Free ◽  
Spreading Model ◽  
Mean Field Equations ◽  
The Impact

Abstract According to the actual situation of investor network, a SE2IR rumor spreading model with hesitating mechanism is proposed, and the corresponding mean-field equations is obtained on scale-free network. In this paper, we first combine the theory of spreading dynamics and find out the basic reproductive number R0. And then analyzes the stability of the rumor-free equilibrium and the final rumor size. Finally, we discuss random immune strategies and target immune strategies for the rumor spreading, respectively. Through numerical simulation, we can draw the following conclusions: Reducing the fuzziness and attractiveness of invest market rumor can effectively reduce the impact of rumor. And the target immunization strategy is more effective than the random immunization strategy for the communicators in the invest investor network.

HEPATITIS C VIRUS AND INTRAVENOUS DRUG MISUSE: A MODELING APPROACH

2014 ◽  
Vol 07 (01) ◽  
pp. 1450006 ◽  
Author(s):  
STEADY MUSHAYABASA ◽  
CLAVER P. BHUNU
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Steady States ◽  
Transmission Dynamics ◽  
Intravenous Drug ◽  
Basic Reproductive Number ◽  
Drug Misuse ◽  
Dynamical Analysis ◽  
Reproductive Number ◽  
The Impact

Hepatitis C virus (HCV) is a blood-borne infection that can lead to progressive liver failure, cirrhosis, hepatocellular carcinoma and death. A deterministic mathematical model for assessing the impact of daily intravenous drug misuse on the transmission dynamics of HCV is presented and analyzed. A threshold quantity known as the reproductive number has been computed. Stability of the steady states has been investigated. The dynamical analysis reveals that the model has globally asymptotically stable steady states. The impact of daily intravenous drug misuse on the transmission dynamics of HCV has been discussed through the basic reproductive number and numerical simulations.

scholarly journals A Simulation on Potential Secondary Spread of Novel Coronavirus in an Exported Country Using a Stochastic Epidemic SEIR Model

2020 ◽  
Vol 9 (4) ◽  
pp. 944 ◽  
Author(s):  
Kentaro Iwata ◽  
Chisato Miyakoshi
Keyword(s):  
Healthcare Professionals ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Asian Countries ◽  
Hospital Visit ◽  
Seir Model ◽  
Stochastic Epidemic ◽  
Novel Coronavirus ◽  
The Impact ◽  
Multiple Scenarios

Ongoing outbreak of pneumonia caused by novel coronavirus (2019-nCoV) began in December 2019 in Wuhan, China, and the number of new patients continues to increase. Even though it began to spread to many other parts of the world, such as other Asian countries, the Americas, Europe, and the Middle East, the impact of secondary outbreaks caused by exported cases outside China remains unclear. We conducted simulations to estimate the impact of potential secondary outbreaks in a community outside China. Simulations using stochastic SEIR model were conducted, assuming one patient was imported to a community. Among 45 possible scenarios we prepared, the worst scenario resulted in the total number of persons recovered or removed to be 997 (95% CrI 990–1000) at day 100 and a maximum number of symptomatic infectious patients per day of 335 (95% CrI 232–478). Calculated mean basic reproductive number (R0) was 6.5 (Interquartile range, IQR 5.6–7.2). However, better case scenarios with different parameters led to no secondary cases. Altering parameters, especially time to hospital visit. could change the impact of a secondary outbreak. With these multiple scenarios with different parameters, healthcare professionals might be able to better prepare for this viral infection.

The Structural Adjustment Programme and the Elderly in Nigeria

1995 ◽  
Vol 41 (4) ◽  
pp. 267-280 ◽  
Author(s):  
Stephen Ekpenyong
Keyword(s):  
Structural Adjustment ◽  
Health Resources ◽  
The Elderly ◽  
Adjustment Programme ◽  
Economic Changes ◽  
Structural Adjustment Programme ◽  
Economic Transformations ◽  
Using Data ◽  
The One ◽  
The Impact

The article analyzes the impact of recent economic changes accompanying the introduction of the Structural Adjustment Programme (SAP) and ongoing cultural styles on the aged in Nigeria. It argues that during the one decade preceding the introduction of SAP in 1986, Nigeria experienced significant social and economic transformations made possible by the rise in oil prices in the 1970s. The introduction of SAP has also been accompanied by significant social, cultural, and economic changes. Here the effects of these changes on the situation of the elderly in Nigeria are examined using data pooled from observations and surveys in both the pre- and post-SAP years. Findings reveal that compared to the younger generations, the relative position of the elderly has not changed significantly, although the latter's position has deteriorated on dimensions such as access to economic and health resources. Regional and individual differentials in the situation of old people are significant during both the pre- and post-SAP era.

scholarly journals Universal scaling law for COVID-19 propagation in urban centers

2020 ◽  
Author(s):  
Ben-Hur Francisco Cardoso ◽  
Sebastián Gonçalves
Keyword(s):  
New York ◽  
Population Density ◽  
Urban Areas ◽  
Transmission Rate ◽  
Scaling Law ◽  
City Size ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Continuous Change ◽  
Urban Centers

Due to the COVID-19 pandemic, there is a high demand for Susceptible-Infective-Recovered (SIR) models to adjust and predict the number of cases in urban areas. Forecasting, however, is a difficult task, because the change in people’s behavior reflects in a continuous change in the parameters of the model. An important question is what we can use from one city to another; if what happened in Madrid could have been applied to New York and then, if what we have learned from this city would be useful for São Paulo. To answer this question, we present an analysis of the transmission rate of COVID-19 as a function of population density and population size for US counties, cities of Brazil, German, and Portugal. Contrary to the common hypothesis in epidemics modeling, we observe a higher disease transmissibility for higher city’s population density/size –with the latter showing more predicting power. We present a contact rate scaling theory that explain the results, predicting that the basic reproductive number R0 of epidemics scales as the logarithm of the city size.

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