Prediction and control of cholera outbreak: Study case of Cameroon.

This paper deals with the problem of the prediction and control of cholera outbreak using real data of Cameroon. We first develop and analyze a deterministic model with seasonality for the cholera, the novelty of which lies in the incorporation of undetected cases. We present the basic properties of the model and compute two explicit threshold parameters and that bound the effective reproduction number , from below and above, that is .

Prediction of pulmonary tuberculosis treatment outcome in a sub-Saharan African context.

Failure to treat many pathogens is a concern. Identifying a priori, patients with potential failure treatment outcome of a disease could allow measures to reduce the failure rate. The objectives of this study were to use the Scoring method to identify factors associated with the tuberculosis unsuccessful treatment outcome and to predict the treatment outcome.

Theoretical Assessment of the Impact of Water Stress on Plants Production: Case of Banana-Plantain.

The aim of this paper is to investigate the role of water stress on plants production. We propose a mathematical model for the dynamics growth of plants that takes into account the concentration of available water in the soil, water stress, plant production and plants compensation. Sensitivity analysis of the model has been performed in order to determine the impact of related parameters on the dynamics growth of plants.

Modelling the Influence of Climatic Factors on the Population Dynamics of Radopholus Similis: Banana-Plantain Pest.

Radopholus Similis (R. Similis) or burrowing nematode, is one of the most damaging and widespread nematodes attacking bananas, causing toppling or blackhead disease. A mathematical model for the population dynamics of R.

Mathematical modeling of COVID-19 pandemic in the context of sub-Saharan Africa: a short-term forecasting in Cameroon and Gabon.

In this paper, we propose and analyse a compartmental model of COVID-19 to predict and control the outbreak. We first formulate a comprehensive mathematical model for the dynamical transmission of COVID-19 in the context of sub-Saharan Africa. We provide the basic properties of the model and compute the basic reproduction number $\mathcal {R}_0$ when the parameter values are constant.

Short-term forecasts of the COVID-19 pandemic: a study case of Cameroon.

In this paper, an Ensemble of Kalman filter (EnKf) approach is developed to estimate unmeasurable state variables and unknown parameters in a COVID-19 model. We first formulate a mathematical model for the dynamic transmission of COVID-19 that takes into account the circulation of free coronaviruses in the environment. We provide the basic properties of the model and compute the basic reproduction number that plays an important role in the outcome of the disease.

Coupling the modeling of phage-bacteria interaction and cholera epidemiological model with and without optimal control.

In this work, we assess the impact of the phage-bacteria infection and optimal control on the indirectly transmitted cholera disease. The phage-bacteria interactions are described by predator-prey system using the Smith functional response, which takes into account the number of bacteria binding sites. The study is done in two steps, namely the model without control and the model with control.

Bifurcation analysis of a phage-bacteria interaction model with prophage induction.

A predator-prey model is used to investigate the interactions between phages and bacteria by considering the lytic and lysogenic life cycles of phages and the prophage induction. We provide answers to the following conflictual research questions: (1) what are conditions under which the presence of phages can purify a bacterial infected environment? (2) Can the presence of phages triggers virulent bacterial outbreaks? We derive the basic offspring number $\mathcal N_0$ that serves as a threshold and the bifurcation parameter to study the dynamics and bifurcation of the system. The model exhibits three equilibria: an unstable environment-free equilibrium, a globally asymptotically stable (GAS) phage-free equilibrium (PFE) whenever $\mathcal N_0<1$, and a locally asymptotically stable environment-persistent equilibrium (EPE) when $\mathcal N_0>1$.

Study of the Population Dynamics of Busseola fusca, Maize Pest.

Busseola fusca is a maize and sorghum pest that can cause significant damage to both crops. Given that maize is one of the main cereals grown in the worldwide, this pest is a major challenge for maize production and therefore for the economies of several countries . In this paper , based on the life cycle of B.

Theoretical Assessment of the Impact of Climatic Factors in a Vibrio Cholerae Model.

A mathematical model for Vibrio Cholerae (V. Cholerae) in a closed environment is considered, with the aim of investigating the impact of climatic factors which exerts a direct influence on the bacterial metabolism and on the bacterial reservoir capacity. We first propose a V.

A patchy model for the transmission dynamics of tuberculosis in sub-Saharan Africa.

Tuberculosis (TB) spreads through contact between a susceptible person and smear positive pulmonary TB case (TPM+). The spread of TB is highly dependent on people migration between cities or regions that may have different contact rates and different environmental parameters, leading to different disease spread speed in the population. In this work, a metapopulation model, i.

Modeling ebola virus disease transmissions with reservoir in a complex virus life ecology.

We propose a new deterministic mathematical model for the transmission dynamics of Ebola Virus Disease (EVD) in a complex Ebola virus life ecology. Our model captures as much as possible the features and patterns of the disease evolution as a three cycle transmission process in the two ways below. Firstly it involves the synergy between the epizootic phase (during which the disease circulates periodically amongst non-human primates populations and decimates them), the enzootic phase (during which the disease always remains in fruit bats population) and the epidemic phase (during which the EVD threatens and decimates human populations).

Parameter and state estimation in a Neisseria meningitidis model: A study case of Niger.

Neisseria meningitidis (Nm) is a major cause of bacterial meningitidis outbreaks in Africa and the Middle East. The availability of yearly reported meningitis cases in the African meningitis belt offers the opportunity to analyze the transmission dynamics and the impact of control strategies. In this paper, we propose a method for the estimation of state variables that are not accessible to measurements and an unknown parameter in a Nm model.

An impulsive modelling framework of fire occurrence in a size-structured model of tree-grass interactions for savanna ecosystems.

Fires and mean annual rainfall are major factors that regulate woody and grassy biomasses in savanna ecosystems. Within the savanna biome, conditions of long-lasting coexistence of trees and grasses have been often studied using continuous-time modelling of tree-grass competition. In these studies, fire is a time-continuous forcing while the relationship between woody plant size and fire-sensitivity is not systematically considered.

Optimal control for an age-structured model for the transmission of hepatitis B.

One of the characteristics of HBV transmission is the age structure of the host population and the vertical transmission of the disease. That is the infection is transmitted directly from infected mother to an embryo, fetus, or baby during pregnancy or childbirth (the perinatal infection). We formulated an age-structured model for the transmission dynamics of HBV with differential infectivity: symptomatic and asymptomatic infections.

Finite-time synchronization of tunnel-diode-based chaotic oscillators.

This paper addresses the problem of finite-time synchronization of tunnel diode based chaotic oscillators. After a brief investigation of its chaotic dynamics, we propose an active adaptive feedback coupling which accomplishes the synchronization of tunnel-diode-based chaotic systems with and without the presence of delay(s), basing ourselves on Lyapunov and on Krasovskii-Lyapunov stability theories. This feedback coupling could be applied to many other chaotic systems.

Spatial analysis of tuberculosis in Douala, Cameroon: clustering and links with socio-economic status.

Setting: Douala, the economic capital of Cameroon, with a network of 20 diagnostic and treatment centres for tuberculosis (TB).

Objective: To describe the spatial distribution of smear-positive pulmonary tuberculosis (PTB) cases in Douala, Cameroon, and to evaluate links between PTB incidence and patients' socio-economic status (SES).

Design: Between May 2011 and April 2012, demographic clinical characteristics and global positioning system coordinates for the residence of each consenting PTB case were collected.

[Management of tuberculosis patients in the urban setting: health service delivery and health care-seeking behavior].

Objectives: This descriptive and prospective study was designed to determine the incidence of smear-positive pulmonary tuberculosis (PTB+) by health area (HA) in Douala, use of Diagnosis and Treatment Centres (DTCs) and the factors influencing the choice of DTC.

Methods: Over a one-year period, the residence of all PTB+ patients and the DTC at which they were treated were located by means of a GPS system and represented on a geo-referenced health map. Incidence of PTB+ per HA was calculated.

Practical time-delay synchronization of a periodically modulated self-excited oscillators with uncertainties.

This paper studies time-delay synchronization of a periodically modulated Duffing Van der Pol (DVP) oscillator subjected to uncertainties with emphasis on complete synchronization. A robust adaptive response system is designed to synchronize with the uncertain drive periodically modulated DVP oscillator. Adaptation laws on the upper bounds of uncertainties are proposed to guarantee the boundedness of both the synchronization error and the estimated feedback coupling gains.

Global stability analysis for SEIS models with n latent classes.

We compute the basic reproduction ratio of a SEIS model with n classes of latent individuals and bilinear incidence. The system exhibits the traditional behaviour. We prove that if R(0) < or = 1, then the disease-free equilibrium is globally asymptotically stable on the nonnegative orthant and if R (0) > 1, an endemic equilibrium exists and is globally asymptotically stable on the positive orthant.

Controlled synchronization of chaotic systems with uncertainties via a sliding mode control design.

This paper addresses the problem of robust adaptive control for synchronization of continuous-time coupled chaotic systems with uncertainties. A general model is studied using measured output state feedback control. An adaptive controller is designed based on a sliding mode control design.