MODELING CHOLERA DYNAMICS WITH VACCINATION AND ASYMPTOMATIC TRANSMISSION: A MATHEMATICAL FRAMEWORK FOR OUTBREAK CONTROL

Résumé

Cholera continues to be a serious problem in area where clean water and good sanitation are hard to find. This study presents a new mathematical model that includes two key aspects of cholera transmission that other studies ignored. These are: vaccination that loses effectiveness over time, and people with the disease, who spread it without showing symptoms (asymptomatic class), represented by A. The model divides the population into seven groups- the susceptible individuals (S) vaccinated individuals (V), asymptomatic infected (A), symptomatic infected (I), centered individuals (C), recovered individuals (R), and bacteria concentration in the water (B). We calculated the basic reproduction number (R0) and showed that when R0< 1, the disease will die out. Using data from recent outbreaks (2022-2024), simulations were run to compare different control strategies. Sanitation measures alone reduced total cases by 43.1 %, vaccination by 37.3 %, and treatment by 28.0 %. Combining vaccination with sanitation reduced cases by 69 %, showing these approaches work better together. It is shown from our analysis that human-to-human transmission rate (β1), environment- to-human transmission rate (β2), and vaccine effectiveness (σ) are the most important factors to control. These results support using combined vaccination and water, sanitation, and hygiene (WASH) programs to control cholera outbreaks.