Optimal strategies for control of cholera in the presence of hyper-infective individuals

Abstract

Cholera is a potentially life-threatening bacterial infection caused by the bacterium Vibrio cholerae, with the primary site of infection being the small intestine. The disease typically spreads through contaminated water and food and becomes more pronounced in areas with poor sanitation and inadequate access to clean drinking water. Cholera infection can lead to severe diarrhoea, dehydration, and death if left untreated. Individuals with low personal hygiene have higher chances of spreading and/or contracting the disease. This study aims to propound a non-linear deterministic model to study the dynamics of cholera in the presence of two groups of individuals based on their level of personal hygiene. We categorize these individuals into low-risk and high-risk to describe individuals with good personal hygiene and those with very low personal hygiene, respectively. The model is shown to have two mutually exclusive fixed points, namely, the cholera-free and the cholera-persistent equilibria, indicating the presence of forward bifurcation. It is shown that restriction of the basic reproduction number below unity guarantees local asymptotic stability of the cholera-free fixed point. The immigration rate, rate of disinfection, bacteria ingestion rate, and bacterial shedding rate are parameters with a higher impact on cholera spread. Optimal control analysis is also used to determine the most cost-effective combination of infection control, adherence to sanitation protocols, treatment control, and bacterial-shedding controls needed to control the spread of cholera.