Optimal Control Analysis of Onchocerciasis through Multiple Integrated
Control Measures
Abstract
Onchocerciasis also known as River Blindness, is a vector-borne disease
caused by Onchocerca volvulus and transmitted by infected female
blackflies. It affects millions of people globally, with the greatest
impact in sub-Saharan Africa. In this study, we develop a deterministic
mathematical model that integrates multiple control measures, including
Sterile Insect Technique (SIT), mechanical control, chemical control,
public health education and ivermectin treatment, to manage the
transmission of onchocerciasis. We employ the next-generation matrix
method to calculate the blackfly offspring reproduction number N 0 and
the basic reproduction number R 0 . Sensitivity analysis, conducted
using the normalized forward sensitivity index, highlights the biting
rate as the most positive influence on driving onchocerciasis dynamics,
while the mortality rate of female blackflies has a significant negative
impact on disease containment. To identify the optimal control strategy,
we apply optimal control theory, considering five time-dependent
controls which are public health education, treatment, mechanical
control, SIT and chemical control. Using Pontryagin’s maximum principle,
we derive the optimality system for controlling onchocerciasis. By
implementing forward-backward Runge-Kutta method in Matlab, we identify
the most optimal strategy for controlling, preventing and treating
onchocerciasis in both human and blackfly populations. The results
suggest that a combined strategy focusing on public health education,
treatment and SIT offers the most effective approach for combating
onchocerciasis.