Browsing by Author "Kgosimore, Moatlhodi"

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Backward Bifurcation and Optimal Control Analysis of a Trypanosoma brucei rhodesiense Model
(MDPI, 2019-10-14) Helikumi, Mlyashimbi; Kgosimore, Moatlhodi; Kuznetsov, Dmitry; Mushayabasa, Steady
In this paper, a mathematical model for the transmission dynamics of Trypanosoma brucei rhodesiense that incorporates three species—namely, human, animal and vector—is formulated and analyzed. Two controls representing awareness campaigns and insecticide use are investigated in order to minimize the number of infected hosts in the population and the cost of implementation. Qualitative analysis of the model showed that it exhibited backward bifurcation generated by awareness campaigns. From the optimal control analysis we observed that optimal awareness and insecticide use could lead to effective control of the disease even when they were implemented at low intensities. In addition, it was noted that insecticide control had a greater impact on minimizing the spread of the disease compared to awareness campaigns
Building the future One Health workforce in Eastern and Southern Africa: Gaps and opportunities
(CABI, 2025-04-10) Wako, Buke; Richards, Shauna; Grace, Delia; Mutie, Ianetta; Caron, Alex; Nys, Helen; Goregena, Brighton; Kgosimore, Moatlhodi; Kimaro, Esther; Qekwana, Nenene; Tadesse, Yordanos; Knight-Jones, Theo; Mutua, Florence
The Quadripartite comprised of the Food and Agriculture Organization (FAO), World Health Organization (WHO), World Organisation for Animal Health (WOAH), the United Nations Environment Program (UNEP), and the One Health High Level Expert Panel collectively support enhancing the One Health (OH) capacities of the workforce addressing OH issues; however, competencies for this workforce are not generally agreed upon, applied uniformly, or always relevant in the global South. The objectives of this study were to (1) develop an inventory of OH education offered by higher education institutes in Eastern and Southern Africa, and (2) define OH competencies relevant for OH training in Eastern and Southern Africa. A survey in 11 Eastern and Southern African countries was conducted with OH key informants purposively selected from higher education institutes offering OH education (n = 1–3/higher education institutes). Snowball sampling was used to identify additional higher education institutes/individuals. Results were validated by OH country representatives. Data were collected using questionnaires, and descriptive statistics were used to present the results. Forty-two questionnaires were completed from 29 higher education institutes, and 166 OH education interventions were reported with 69% being courses contributing to a degree, 21% as degree/diploma awarding, and the remainder were missing data (n = 16). Masters were the most common OH degree program of which the highest number of students taught were from public health/OH, food safety, and applied epidemiology. There are many OH educational courses and activities on offer in Eastern and Southern Africa; however, their total breadth is difficult to assess due to limited awareness of the availability of OH education not only between higher education institutes in a country but also even within a higher education institute between faculties. Numerous cross-cutting and technical competencies were considered essential to work in OH; however, this level of expertise is rarely logistically possible to provide in any single degree program. For OH education to be consistently applied, competency frameworks that are relevant to a region are necessary. Technical competencies are important from a disciplinary context; however, necessary cross-cutting competencies should be a focus in developing the future OH workforce.
Dynamical and optimal control analysis of a seasonal Trypanosoma brucei rhodesiense model
(AIMS Press, 2020-02-27) Helikumi, Mlyashimbi; Kgosimore, Moatlhodi; Kuznetsov, Dmitry; Mushayabasa, Steady
The e ects of seasonal variations on the epidemiology of Trypanosoma brucei rhodesiense disease is well documented. In particular, seasonal variations alter vector development rates and behaviour, thereby influencing the transmission dynamics of the disease. In this paper, a mathematical model for Trypanosoma brucei rhodesiense disease that incorporates seasonal e ects is presented. Owing to the importance of understanding the e ective ways of managing the spread of the disease, the impact of time dependent intervention strategies has been investigated. Two controls representing human awareness campaigns and insecticides use have been incorporated into the model. The main goal of introducing these controls is to minimize the number of infected host population at low implementation costs. Although insecticides usage is associated with adverse e ects to the environment, in this study we have observed that by totally neglecting insecticide use, e ective disease management may present a formidable challenge. However, if human awareness is combined with low insecticide usage then the disease can be e ectively managed.
Dynamical modeling of Salmonellosis in humans and dairy cattle with temperature and pH effects
(Elsevier Ltd., 2025-03) Trazias, Herman; Mayengo, Maranya; Irunde, Jacob; Kgosimore, Moatlhodi
Approximately 20 million cases and 0.15 million human fatalities worldwide each year are caused by Salmonellosis. A mechanistic compartmental model based on ordinary differential equations is proposed to evaluate the effects of temperature and pH on the transmission dynamics of Salmonellosis. The transmission potential of the disease in areas with temperature and pH stresses is examined. The next-generation matrix method is applied to compute the temperature-pH-dependent reproduction number . The dynamical regimes of the system are examined using Lyapunov stability theory and backward bifurcation analysis. The uncertainty and global sensitivity analysis are examined using the Latin Hypercube Sampling (LHS) and Partial Rank Correlation Coefficient (PRCC) methods. The numerical simulations of the proposed model under favorable and unfavorable temperatures are performed with a confidence interval (CI) for the reliability assessment of the model parameters. The analysis shows that the ingestion rates of Salmonella enterica subsp. enterica serovar Typhimurium bacteria in humans and dairy cattle, human-to-human transmission rate, cattle-to-cattle transmission rate, human shedding rate, dairy cattle shedding rate, and the rate of producing contaminated dairy products are directly proportional to the number of infected humans and infected dairy cattle. The temperature ranges of and and pHs greater than 3.8 have a significant effect on the dynamics of Salmonellosis. In order to eliminate Salmonellosis, the study recommends treating natural water bodies using the recommended chemical disinfectants during summer seasons and in areas with temperature ranges of , cooking food at the hottest temperatures, and storing food at the lowest temperatures for all pHs.
A fractional-order Trypanosoma brucei rhodesiense model with vector saturation and temperature dependent parameters
(Springer Nature, 2020-06-11) Helikumi, Mlyashimbi; Kgosimore, Moatlhodi; Kuznetsov, Dmitry; Mushayabasa, Steady
Temperature is one of the integral environmental drivers that strongly affect the distribution and density of tsetse fly population. Precisely, ectotherm performance measures, such as development rate, survival probability and reproductive rate, increase from low values (even zero) at critical minimum temperature, peak at an optimum temperature and then decline to low levels (even zero) at a critical maximum temperature. In this study, a fractional-order Trypanosoma brucei rhodesiense model incorporating vector saturation and temperature dependent parameters is considered. The proposed model incorporates the interplay between vectors and two hosts, humans and animals. We computed the basic reproduction number and established results on the threshold dynamics. Meanwhile, we explored the effects of vector control and screening of infected host on long-term disease dynamics. We determine threshold levels essential to reducing the basic reproduction number to level below unity at various temperature levels. Our findings indicate that vector control and host screening could significantly control spread of the disease at different temperature levels.
Fuzzy Modeling for the Dynamics of Alcohol-Related Health Risks with Changing Behaviors via Cultural Beliefs
(Hindawi, 2020-07-13) Mayengo, Maranya; Kgosimore, Moatlhodi; Chakraverty, Snehashish
In this paper, we propose and analyze a fuzzy model for the health risk challenges associated with alcoholism. The fuzziness gets into the system by assuming uncertainty condition in the measure of influence of the risky individual and the additional death rate. Specifically, the fuzzy numbers are defined functions of the degree of peer influence of a susceptible individual into drinking behavior. The fuzzy basic risk reproduction number is computed by means of Next-Generation Matrix and analyzed. The analysis of reveals that health risk associated with alcoholism can be effectively controlled by raising the resistance of susceptible individuals and consequently reducing their chances of initiation of drinking behavior. When perceived respectable individuals in the communities are involved in health education campaign, the public awareness about prevailing risks increases rapidly. Consequently, a large population proportion will gain protection from initiation of drinks which would accelerate their health condition into more risky states. In a situation where peer influence is low, the health risks are likely to be reduced by natural factors that provide virtual protection from alcoholism. However, when the perceived most influential people in the community engage in alcoholism behavior, it implies an increase in the force of influence, and as such, the system will be endemic.
A mathematical model for fall armyworm management on maize biomass
(Springer Nature, 2021-02-04) Daudi, Salamida ; Luboobi, Livingstone; Kgosimore, Moatlhodi; Kuznetsov, Dmitry; Mushayabasa, Steady
Fall armyworm (Spodoptera frugiperda), a highly destructive and fast spreading agricultural pest native to North and South America, poses a real threat to global food security. In this paper, to explore the dynamics and implications of fall armyworm outbreak in a field of maize biomass, we propose a new dynamical system for maize biomass and fall armyworm interaction via Caputo fractional-order operator, which is not only a nonlocal operator but also contains all characteristics concerned with memory of the dynamical system. We define the basic reproduction number, which represents the average number of newborns produced by one individual female moth during its life span. We establish that the basic reproduction number is a threshold quantity, which determines persistence and extinction of the pest. Finally, we simulate the Caputo system using the Adam–Bashforth–Moulton method to illustrate the main results.
Mathematical models for the dynamics of alcohol related health risks with changing behavior via cultural beliefs in Tanzania
(Communications in Mathematical Biology and Neuroscience, 2021-03) Mayengo, Maranya; Kgosimore, Moatlhodi; Chakraverty, Snehashish; Seshaiyer, Padmanabhan; Caiseda, Carmen; Shirima, Gabriel
Alcoholism has continually posed health challenges in many communities for decades. In this paper, a more realistic model for health related risks associated with alcoholism is formulated. It considers a population proportion that has social cultural protection from alcohol consumption. In the context of this paper, such protection emanates from religious beliefs. The Next Generation Matrix (NGM) approach is used to compute the basic risk reproduction number. The risk free equilibrium point is proved to be globally asymptotically stable whenever the basic risk reproduction is less than unity and unstable otherwise. The sensitivity analysis of the basic risk reproduction number and numerical simulation results reveal that for effective control of the health risk problem in the community, the deliberate intervention strategies and policies should focus on discouraging alcoholic behaviors on its onset during initiation stage than focusing other population proportions already at risk.
Modeling salmonellosis transmission dynamics in humans and dairy cattle with optimal controls
(Elsevier, 2025-02) Trazias, Herman; Irunde, Jacob; Kgosimore, Moatlhodi; Mayengo, Maranya
In this paper, we develop a mathematical model to examine the transmission dynamics and control analysis of salmonellosis in humans and dairy cattle. The model considers three time-dependent controls (improving hygiene, vaccination, and organic acid disinfectants), human and dairy cattle populations, and Salmonella typhimurium bacteria in the environments and dairy products. The next generation matrix technique is applied to compute the effective reproduction number that gauges the persistence and extinction of salmonellosis while adopting the proposed control interventions. The stability behavior of the equilibrium states is examined using the Lypunov function method based on the effective reproduction number . The Latin hypercube sampling and the partial rank correlation coefficient methods are used to investigate the sensitivity and uncertainty of input parameters against model outputs. The results indicate that improving hygiene and vaccination can eliminate salmonellosis. Improving hygiene habits at a rate of at least 0.9 per day is recommended to eliminate salmonellosis. An efficacious vaccine that can immunize at least 85% of the vaccinated dairy cattle is also recommended to eradicate salmonellosis if it can be implemented to vaccinate susceptible dairy cattle at a rate of at least 0.45 per day for the first 30 days of the salmonellosis outbreak. The use of all three controls is recommended to eliminate salmonellosis quickly and at the lowest cost.
Modeling the effects of contaminated environments on the transmission dynamics of avian influenza in humans and domestic birds
(Elsevier, 2025-09) Soka, Serapia; Mayengo, Maranya; Kgosimore, Moatlhodi
Avian influenza is a viral infection that affects birds and can spread to humans and other animals, causing severe illness and high mortality in both populations. Migratory birds are the primary transmitters of the virus, shedding it into the environment. This study investigates the effects of contaminated environments in the transmission dynamics of avian influenza. We suggest a deterministic mathematical model to capture the interactions between humans, domestic birds, and contaminated environments. A model takes the form of a system of non-linear ordinary differential equations. The next-generation matrix technique calculates the basic reproduction number (). The stability of both the disease-free and endemic equilibrium points is analyzed. When, the avian influenza free equilibrium is globally asymptotically stable, whereas when, the endemic equilibrium is globally asymptotically stable. The Latin Hypercube Sampling (LHS) and partial rank correlation coefficients (PRCC) methods are employed to assess the sensitivity of the model parameters. A numerical simulation is performed to investigate the effects of different model parameters associated with environmental contamination towards. The results indicate that the transmission rates of the avian influenza virus by humans and domestic birds are directly proportional.
Modelling the Control of the Impact of Fall Armyworm (Spodoptera frugiperda) Infestations on Maize Production
(Hindawi, 2021-02-18) Daudi, Salamida; Luboobi, Livingstone; Kgosimore, Moatlhodi; Kuznetsov, Dmitry
In this paper, we propose and analyze a stage-structured mathematical model for modelling the control of the impact of Fall Armyworm infestations on maize production. Preliminary analysis of the model in the vegetative and reproductive stages revealed that the two systems had a unique and positively bounded solution for all time . Numerical analysis of the model in both stages under two different cases was also considered: Case 1: different number of the adult moths in the field assumed at and Case 2: the existence of exogenous factors that lead to the immigration of adult moths in the field at time . The results indicate that the destruction of maize biomass which is accompanied by a decrease in maize plants to an average of 160 and 142 in the vegetative and reproductive stages, respectively, was observed to be higher in Case 2 than in Case 1 due to subsequent increase in egg production and density of the caterpillars in first few (10) days after immigration. This severe effect on maize plants caused by the unprecedented number of the pests influenced the extension of the model in both stages to include controls such as pesticides and harvesting. The results further show that the pest was significantly suppressed, resulting in an increase in maize plants to an average of 467 and 443 in vegetative and reproductive stages, respectively.