Dynamics of leptospirosis in human and rodent populations: a multiscale modeling approach

Leptospirosis is a bacteria infection prevalent in many tropical regions, caused by the genus Leptospira. Humans contract the disease by coming in contact with contaminated environments. This study proposes a deterministic mathematical model that links the within-host and between-host dynamics of leptospirosis and investigates its properties. The model's parameters were estimated by fitting it to real-life data using the "lsqcurvefit" package in MATLAB. The study employs global sensitivity analysis using Latin hypercube sampling with a partial rank correlation coefficient index and uses Pontryagin's maximum principle to identify cost-effective solutions for time-dependent intervention strategies to suppress the bacteria transmission within a specific period. The results of the study showed that bacteria replication within human and rodent hosts is the major driver of the overall dynamics of leptospirosis and therefore controlling the prevalence of the disease by focusing on the epidemiology components is necessary but will not be effective if the intra-host dynamics of the bacteria within rodent hosts and human hosts are not attentively considered.