Modelling the spread of schistosomiasis in humans with environmental transmission

Although schistosomiasis containment campaigns have recorded substantial success in most developed countries, sub-Saharan Africa still suffers greatly under the burden of the disease. A basic mathematical model to assess the impact of concomitant immunity in humans and environmental transmission of schistosomiasis disease progression is formulated. Mathematical analysis is carried out to establish the existence of the equilibrium points providing necessary conditions for their local and global stability. Numerical simulations are done to analyze the effects of environmental transmission and processes associated with development of concomitant immunity. Our results suggest that schistosomiasis burden is increased by direct and indirect contribution of individuals with concomitant immunity to the schistosomiasis infection chain, increasing the shedding of miracidia upto the development of cercariae promoting the growth of cercariae, increase in environmental transmission due to cercariae, reducing the clearance rate of cercariae and reducing the development of humans and non-human mammals escape mechanisms from cercariae attack. (c) 2021 Elsevier Inc. All rights reserved.