Steady Mushayabasa

• PhD
• University of Zimbabwe

Cassava remains Sub-Saharan Africa's second most crucial staple food crop after maize. However, production of sufficient yields is hampered by pests and diseases. In particular, the whitefly (Bemisia tabaci) has the potential to reduce expected yields by 50% since it directly damages cassava leaves by feeding on phloem, causing chlorosis and abscis...

Immunisation of livestock with high-quality vaccines and the use of acaricides are highly ranked tick control strategies worldwide. However, the effects of coupling livestock immunisation and acaricide control on mitigating the spread of East Coast Fever (ECF) is not well understood. Effective strategies to curb the disease require an understanding...

A free-roaming dog population remains one of the major public health problems in many developing countries. In this study, we investigated the potential impact of owned roaming and stray dogs on the persistence and possible eradication of Guinea worm disease (GWD) in Chad. We developed and analysed a multi-host of Guinea worm; and considered dogs a...

In this paper, we propose a fractional order Coronavirus (COVID-19) model incorporating non-pharmaceutical interventions and vaccine hesitancy. The proposed model was calibrated with data from literature and validated with reported daily cases of COVID-19 from Wuhan, China. We derived the reproduction number and demonstrated that it is an important...

Spillover of trypanosomiasis parasites from wildlife to domestic livestock and humans remains a major challenge world over. With the disease targeted for elimination by 2030, assessing the impact of control strategies in communities where there are human-cattle-wildlife interactions is therefore essential. A compartmental framework incorporating t...

In recent decades, media campaigns have played an important role in assessing, preventing and controlling infectious diseases. However, little progress has been made in quantifying its impact during chikungunya epidemics. In order to address this critical gap, this paper develops and analyzes a climate-based model of chikungunya virus disease that...

Approximately 1.3 billion inhabitants in 94 countries are estimated to be at risk of chikungunya virus infection. A mechanistic compartmental model based on fractional calculus, the Caputo derivative has been proposed to evaluate the effects of temperature and multiple disease control measures (larvicides use, insecticides and physical barriers) du...

Despite having been tested in multiple settings, the quantitative impact of predatory aquatic insects to reduce mosquito population remains unclear. To address this question, an ecological model of Aedes mosquito population incorporating temperature-dependent entomological parameters and predation is developed. The vector reproduction number is der...

Within the last decades, chikungunya virus (CHIKV), a mosquito-borne arboviral disease transmitted by Aedes species mosquitoes has been a growing public health burden. Approximately 1.3 billion inhabitants in 94 countries are estimated to be at risk of chikungunya virus infection. Prior studies suggest that temperature and heterogeneous biting expo...

In this paper, a nonlinear fractional-order chikungunya disease model that incorporates asymptomatic infectious individuals is proposed and analyzed. The main interest of this work is to investigate the role of memory effects on the dynamics of chikungunya. Qualitative analysis of the model’s equilibria showed that there exists a threshold quantity...

We propose a new fractional-order model to investigate the transmission and spread of Ebola virus disease. The proposed model incorporates relevant biological factors that characterize Ebola transmission during an outbreak. In particular, we have assumed that susceptible individuals are capable of contracting the infection from a deceased Ebola pat...

To understand the effects of animal movement on transmission and control of brucellosis infection, a reaction diffusion partial differential equation (PDE) brucellosis model that incorporates wild and domesticated animals under homogeneous Neumann boundary conditions is proposed and analysed. We computed the reproductive number for the brucellosis...

In this paper, we propose a nonlinear fractional-order model in order to explain and understand the outbreaks of foot-and-mouth disease. The proposed model rely on the Caputo operator. We computed the basic reproduction number and demonstrated that it is an important metric for extinction and persistence of the disease. Utilizing reported foot-and-...

In this paper, we proposed and analyzed a non-autonomous sleeping sickness that incorporates host and vector movement in a periodic environment. The proposed model is a two patch framework that has three species-humans, animals and tsetse flies. In addition to seasonality and mobility aspects, the proposed model also incorporates vector-bias. Due t...

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...

In this paper, a fractional-order model that describes transmission and control of foot-and-mouth disease is presented and analyzed. The proposed model incorporates two foot-and-mouth disease intervention strategies: vaccination of susceptible animals and quarantine of clinically infected animals. Firstly, the global existence, positivity and bound...

Herpes simplex virus type 2 (HSV-2) is the most prevalent sexually transmitted infection in the world, despite the availability of effective anti-viral treatments. A mathematical model to explore the association between gender and HSV-2 treatment adherence is developed. Threshold parameters are determined and stabilities analyzed. Sensitivity analy...

Foot-and-mouth disease virus remains one of the most important livestock diseases in sub-Saharan Africa and several Southeast Asian countries. Vaccination of livestock has been recognized as an important tool for the control of foot-and-mouth disease virus. However, this intervention strategy has some limitations. Generally, vaccine production is a...

We applied optimal control theory to a mathematical model for guinea worm disease, to determine the effectiveness of optimal education campaigns on long-term dynamics of the disease. Our model is concerned with two different host populations, represented by two patches, sharing a common water source. We computed the basic reproduction number of the...

We applied optimal control theory to a mathematical model for guinea worm disease, to determine the effectiveness of optimal education campaigns on long-term dynamics of the disease. Our model is concerned with two different host populations, represented by two patches, sharing a common water source. We computed the basic reproduction number of the...

Mathematical models proffer a rational basis to epidemiologists and policy makers on how, where and when to control an infectious disease. Through mathematical models one can explore and provide solutions to phenomena which are difficult to measure in the field. In this paper, a mathematical models has been used to explore the role of government an...

Abstract 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 temper...

The effects 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 incorp...

A mathematical model for the transmission dynamics of foot-and-mouth disease that incorporates direct and indirect disease transmission pathways as well as vaccine failure and culling clinically infected animals is developed, analyzed and simulated. The basic reproduction number of the model is determined and qualitatively used to investigate the g...

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 th...

Leprosy, one of the neglected tropical diseases is a chronic, debilitating, disabling and disfiguring condition that occur most commonly in the setting of extreme poverty, especially among the rural poor and some disadvantaged urban populations. We formulate a deterministic mathematical model to investigate the impact of relapse cases and non-compl...

Short-term animal movements play an integral role in the transmission and control of zoonotic infections such as brucellosis, in communal farming zones where animal movements are highly uncontrolled. Such movements need to be incorporated in models that aim at informing animal managers effective ways to control the spread of zoonotic diseases. We d...

We introduce a new mathematical modeling framework that seek to improve our quantitative understanding of the influence of chronic brucellosis and culling control on brucellosis dynamics in periodic and non-periodic environments. We conduct both epidemic and endemic analysis, with a focus on the threshold dynamics characterized by the basic reprodu...

We present a mathematical model for brucellosis transmission that incorporates two discrete delays and culling of infected animals displaying signs of brucellosis infection. The first delay represents the incubation period while the second account for the time needed to detect and cull infectious animals. Feasibility and stability of the model stea...

Guinea worm disease is one of the neglected tropical diseases that is on the verge of elimination. Currently the disease is endemic in four countries, namely, Ethiopia, Mali, Chad, and South Sudan. Prior studies have demonstrated that climate factors and limited access to safe drinking water have a significant impact on transmission and control of...

In this paper, we propose a nonlinear modeling framework to investigate the transmission dynamics of brucellosis, incorporating both the spatial and seasonal variations. The spatial modeling is based on a patch structure, and the seasonal impact is represented by utilizing time-periodic model parameters. We demonstrate this framework through a two-...

While the effects of unemployment on property crime has been recognized for decades, finding a comprehensive and effective strategy for its control remains a global challenge. A mathematical model of property crime “epidemic” that incorporates the effects of unemployment, in a rather simple setting, is proposed and analysed. The model subdivides th...

In this paper, we consider global stability for an anthrax model with distributed delay. The model incorporates vaccination and carcass disposal. The basic reproduction number of the anthrax model is derived, which completely determine the stability of equilibria. By using the direct Lyapunov method and constructing appropriate Lyapunov functional,...

In this paper, we consider global stability for an anthrax model with distributed delay. The model incorporates vaccination and carcass disposal. The basic reproduction number of the anthrax model is derived, which completely determine the stability of equilib-ria. By using the direct Lyapunov method and constructing appropriate Lyapunov functional...

In an effort to slow transmission of blood-borne pathogens among intravenous drug misusers, clinicians through harm reduction programs have tried to educate intravenous drug misusers about the dangers of sharing needles and other injecting equipment. These programs encourage the use of new needles for every injection or, when new equipment is not a...

Prior studies have indicated that adolescents who are into sexting are likely to engage in risky sexual behaviours. In this paper, a mathematical model to assess the impact of sexting and peer influence on the spread of HSV-2 amongst adolescents is developed. The threshold parameters of the model are determined and stabilities are analysed. The imp...

The global burden of death and disability attributable to illicit drug use, remains a significant threat to public health for both developed and developing nations. This paper presents a new mathematical modeling framework to investigate the effects of illicit drug use in the community. In our model the transmission process is captured as a social...

We propose a new mathematical modeling framework to investigate the transmission and spread of foot-and-mouth disease. Our models incorporate relevant biological and ecological factors, vaccination effects, and seasonal impacts during the complex interaction among susceptible, vaccinated, exposed, infected, carrier, and recovered animals. We conduc...

Anthrax is an acute infectious disease caused by the spore-forming bacterium Bacillus anthracis. It occurs most frequently as a disease of herbivores (e.g., cattle, goats and sheep) that acquire spores from direct contact with contaminated soil. In this paper, we formulate a new mathematical modeling framework to explore the spread of anthrax in th...

Herpes simplex virus type 2 (HSV-2) is the most prevalent sexually transmitted disease worldwide, despite the availability of highly effective antiviral treatments. In this paper, a basic mathematical model for the spread of HSV-2 incorporating all the relevant biological details and poor treatment adherence is proposed and analysed. Equilibrium st...

Anthrax occurs worldwide and is associated with sudden death of cattle and sheep. This paper considers an epidemic model of anthrax in animal population, only. The susceptible animal is assumed to be infected, only, through ingestion of the disease causing pathogens. The proposed model incorporates time delay and environmental decontamination by hu...

Foot-and-mouth disease (FMD) is a threat to economic security and infrastructure as well as animal health, in both developed and developing countries. We propose and analyze an optimal control problem where the control system is a mathematical model for FMD that incorporates vaccination and culling of infectious animals. The control functions repre...

We propose and analyze a mathematical model for alcohol drinking problem. The transmission process is modeled as a social ``contact" process between ``heavy" alcohol drinkers and ``light" alcohol drinkers within an unchanging shared drinking environment. The basic reproductive number of the model is computed and the stability of the model steady st...

To explore the impact of Trichomonas Vaginalis on HIV transmission and vice-versa.

The prevalence of herpes simplex virus type 2 (HSV-2) is on the rise within the general population and no perfect vaccine has been found yet. In this paper, a mathematical model for the spread of HSV-2 is developed and analysed. The impact of counselling/educational campaigns, vaccination and treatment are examined. The disease free equilibrium has...

Herpes simplex virus infection is mostly spread and occurs more commonly among substance abusing adolescents as compared to the nonsubstance abusing. In this paper, a mathematical model for the spread of HSV-2 within a community with substance abusing adolescents is developed and analysed. The impacts of condom use and educational campaigns are exa...

HIV/AIDS has been somehow linked to prostitution for decades now. A mathematical model is presented to assess the link between prostitution and HIV transmission. The epidemic thresholds known as the reproduction numbers and equilibria for the model are determined and stabilities analyzed. Analysis of the reproduction numbers suggests that HIV/AIDS...

A deterministic model for the transmission dynamics of typhoid fever is developed and qualitative analyzed. Infectious symptomatic and asymptomatic individuals are detected and quarantined. The impact of time dependent screening of infectious individuals is explored. Comprehensive analysis of the model suggest that time dependent screening can be e...

Aim Since its emergence in the 1980s, the human immunodeficiency virus (HIV), the causative agent of the acquired immune deficiency syndrome (AIDS), remain a major challenge to the global health and human development. We explore the role of optimal HIV counseling and support groups on combating new infections. Background The stigma surrounding HIV...

Hepatitis C virus (HCV) remains a major health challenge despite the availability of highly effective antiviral drugs. Prior studies suggest that many physicians are reluctant to treat intravenous drug misusers due to low levels of treatment adherence associated with intravenous drug misusers. HCV treatment guidelines and recommendations stipulate...

Despite advances in hepatitis C therapy and better knowledge of viral/host factors related to disease progression, hepatitis C virus (HCV) remains the leading cause of chronic liver disease, causing progression to end-stage liver disease (ESLD) as well as the development of hepatocellular carcinoma. In this paper a mathematical model for assessing...

Typhoid and malaria co-infection is a major public health problem in many developing countries. In this paper, a deterministic model for malaria and typhoid co-infection is proposed and analyzed. It has been established that the model exhibits a backward bifurcation phenomenon. Overall, the study reveals that a typhoid outbreak in malaria endemic s...

Background Approximately 85% of the individuals infected with hepatitis C virus develop chronic infection. Hepatitis C virus and HIV/AIDS infections are common in some parts of the world, and due to their geographical overlap, co-infection cannot be ruled out as the two diseases have the same transmission route. The study of their joint dynamics is...

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 numbe...

A deterministic model for transmission dynamics of Trichomonas vaginalis in a population with bisexuals is formulated and analysed. The disease free equilibrium point has been shown to be globally asymptotically stable when the reproduction number is less than a unity. Furthermore, the endemic equilibrium point has been shown to be locally asymptot...

All over the world, tuberculosis is a public health problem in prisons due to the fact that many inmates come from communities at high risk of tuberculosis, to their living conditions in prisons and to the insufficiencies of prisons health services. In this paper, Wells–Riley’s equation for modeling airborne infection within indoor environment is i...

Effective tuberculosis (TB) control depends on case findings to discover infectious cases, investigation of contacts of those with TB, as well as appropriate treatment. Adherence and successful completion of the treatment are equally important. Unfortunately, due to a number of personal, psychosocial, economic, medical, and health service factors,...

Coinfection with HIV and hepatitis C virus (HCV) is a significant problem, espe-cially among intravenous drug users (IDUs). Prior studies suggests that imprisonment is a major risk factor for blood-borne infections, with the risk of infection directly proportional to the length of incarceration. Further, analysis of prison life reveals that inmates...

The prevalence of infection with hepatitis C virus (HCV) is higher among prison inmates compared with the general population because of the high proportion of intravenous drug misusers. In this paper, a mathematical model for the spread of HCV in correctional institutions is developed and analyzed. The impact of educational campaigns and screening...

The prevalence of infection with hepatitis C virus (HCV) is higher among prison inmates compared with the general population because of the high proportion of intravenous drug misusers. In this paper, a mathematical model for the spread of HCV in correctional institutions is developed and analyzed. The impact of educational campaigns and screening...

Typhoid fever continues to be an important cause of illness and death in developing countries where safe water supply, environmental sanitation and food hygiene are not optimal. An epidemiological model for direct and indirect transmission of typhoid is formulated and studied. The basic reproductive number is calculated and the global stability is...

Typhoid fever continues to be a major public health problem in the developing world. Antibiotic therapy has been the main stay of treating typhoid fever for decades. The emergence of drug-resistant typhoid strain in the last two decades has been a major problem in tackling this scourge. A mathematical model for investigating the impact of drug resi...

Scabies is among the infestations almost forgotten due to its association with poor communities. We formulate a deterministic model to assess the possible impact vaccination will have on scabies control. The Descartes’s rule of signs is used to show the nature of the endemic equilibria. Analysis of the reproduction number and numerical simulations...

Intravenous drug use and tattooing remain one of the major routes of HIV/AIDS transmission among prisoners. We formulate and analyze a deterministic model for the role of intravenous drug use in HIV/AIDS transmission among women prisoners. With the aid of the Centre Manifold theory, the endemic equilibrium is shown to be locally asymptotically stab...

Unsafe injecting practices, blood exchange, the use of non-sterile needles, and other cutting instruments for tattooing are common in correctional institutions, resulting in a number of blood transmitted infections. A mathematical model for assessing the dynamics of HCV and HIV co-infection within correctional institutions is proposed and comprehen...

Drug misuse (injecting drug users-IDU) has been recognized to have a significant effect on the spread of HIV/AIDS epidemic. A deterministic model to assess the contribution of drug misuse and sex in the spread of HIV/AIDS is investigated. The threshold parameters of the model are determined and stabilities are analysed. Analysis of the reproduction...

Cholera, an acute intestinal infection caused by the bacterium Vibrio cholerae, remains a major public health problem in many parts of Africa, Asia, and Latin America. A mathematical model is developed, to assess the impact of increasing antimicrobial resistance of Vibrio cholerae on the future trends of the cholera epidemic. Equilibrium states of...

A mathematical model for the spread of alcoholism and smoking is designed and analysed to gain insights into this growing health and social problem. The reproduction number and equilibria states of the model are determined and their local asymptotic stabilities investigated. Analysis of the reproduction number have shown conditions under which enco...

An epidemiological model for the spread of lymphatic filariasis, a mosquito-borne infection, is developed and analysed. The epidemic thresholds known as the reproduction number and equilibria for the model are determined and stabilities analysed. Results from the analysis of the reproduction number suggest that treatment will somehow contribute to...

Tuberculosis (TB) transmission is enhanced by poor living conditions. In this study, a deterministic model was developed to assess the impact of socioeconomic conditions on TB transmission, taking into account heterogeneous mixing patterns. The epidemic thresholds known as the reproduction numbers, as well as equilibria for the model, are determine...

Although there is a declining trend in the global burden of leprosy, there are 15 countries in Asia and Africa which account for 94% of the global total of the new-case detection rate. Here, we assess the impact of different intervention strategies aimed at leprosy eradication through targeting non-symptomatic and symptomatic individuals. We develo...

A deterministic model for evaluating the impact of voluntary testing and treatment on the transmission dynamics of tuberculosis is formulated and analyzed. The epidemiological threshold, known as the reproduction number is derived and qualitatively used to investigate the existence and stability of the associated equilibrium of the model system. Th...

Prostitution has been linked with drug/alcohol misuse for ages. A mathematical model to explore the relationship between prostitution and drug/alcohol misuse is proposed and analyzed. The epidemic thresholds known as the reproduction numbers and equilibria for the model are determined and stabilities analyzed. Analysis of the reproduction numbers s...

The ideal intervention against HIV/ AIDS infection will be a highly effective vaccine with long lasting-protection, but unfortunately that is currently non-existent. In this manuscript the potential of antiretroviral drugs when used as pre-exposure vaccines in the fight against the spread of HIV is explored using a mathematical model. Results from...

Cholera, a waterborne gastroenteric infection, remains a significant threat to public health in sub-Saharan Africa, the region most heavily affected by HIV. It is biologically plausible that immune suppression caused by HIV infection predisposes to cholera. In this paper, a simple mathematical model is developed and comprehensively analyzed to asse...

A deterministic model for evaluating the impact of voluntary testing and treatment on the transmission dynamics of tuberculosis is formulated and analyzed. The epidemiological threshold, known as the reproduction number is derived and qualitatively used to investigate the existence and stability of the associated equilibrium of the model system. Th...

During the last two decades, reports on emerging human monkeypox outbreaks in Africa and North America have reminded us that beside the eradicated smallpox there are other pox viruses that have great potential to harm people. A deterministic model for the coinfection of HIV/AIDS and monkeypox is formulated and analysed. The endemic equilibria are s...

Prior studies have shown that imprisonment is a major risk factor for hepatitis C infection, with the risk of infection directly proportional to the length of incarceration. Women are at least twice as likely as men to contract HCV as they have limited access to information, health services and safe intravenous drug injecting equipments. We develop...

A neglected disease with a nearly forgotten name is making a comeback following a global control programme that almost eradicated it more than forty years ago. Until the 1970s the prevalence of non-venereal treponematosis, including yaws, was greatly reduced after worldwide mass treatment. In 2005, cases were again reported in the Democratic Republ...

While chlamydia and gonorrhea may have attracted less attention and, indeed, resources in recent years, their insidious health effects, coupled with the negative social and economic impact, need to be recognized. A deterministic model for assessing the epidemiological consequences of chlamydia and gonorrhea co-infection is formulated and comprehens...

Tuberculosis (TB) transmission is enhanced by poor living conditions. In this study, a deterministic model was developed to assess the impact of socioeconomic conditions on TB transmission, taking into account heterogeneous mixing patterns. The epidemic thresholds known as the reproduction numbers, as well as equilibria for the model, are determine...

The increasing prevalence of antibiotic-resistant gonorrhea world over, marks the latest common pathogen to have shifted from an easily treated infection to a resistant form that is suddenly far more dangerous. A mathematical model which investigates the impact of antibioticresistant gonorrhea on HIV-gonorrhea co-interaction co-dynamics in resource...

Prior studies have indicated that heavy alcohol drinkers are likely to engage in risky sexual behaviours and thus, more likely to get sexually transmitted infections (STIs) than social drinkers. Here, we formulate a deterministic model for evaluating the impact of heavy alcohol drinking on the reemerging gonorrhea epidemic. The model is rigorously...

A sex-structured staged progression model for heterosexual transmission dynamics of HIV/AIDS in a community to theoretically assess the effects of gender parameter accounting for population heterogeneity is formulated and analyzed. The basic model without this parameter is analyzed, and then extended to include gender heterogeneity in order to expl...

HIV/AIDS is one of the most challenging public health burdens worldwide, with more than 34 million people living with the disease at the end of 2010. The epidemic continues to erase decades of health, economic and social progress, reducing life expectancy and deepening poverty in the hardest hit communities. We formulate a deterministic model to in...

A sex-structured staged progression model for heterosexual transmission dynamics of HIV/AIDS in a community to theoretically assess the effects of gender parameter accounting for population heterogeneity is formulated and analyzed. The basic model without this parameter is analyzed, and then extended to include gender heterogeneity in order to expl...

A mathematical model for the transmission dynamics of Hepatitis C virus (HCV) have been proposed and investigated. The model presented looks into preferential sexual contacts between intravenous drug users and non-drug users. The threshold parameters of the model are determined and stabilities analysed. Both analytic and numerical simulations show...

Mathematical models have long been used to better understand disease transmission dynamics and how to effectively control them. Here, a chancroid infection model is presented and analyzed. The disease-free equilibrium is shown to be globally asymptotically stable when the reproduction number is less than unity. High levels of treatment are shown to...

Despite the availability of treatment that is effective, Trichomonas vaginalis infections are still high. A deterministic model for transmission dynamics of Trichomonas vaginalis is presented as a system of non-linear differential equations. Analysis of the reproduction number has shown that an increase in the number of straight women (non-lesbians...