Management and control of schistosomiasis in Agusan del Sur, Philippines: A modeling study

Abstract

Schistosomiasis is a neglected tropical disease endemic in the Philippines, affecting 28 provinces in 12 regions. This parasitic disease is caused by Schistosoma japonicum, a zoonotic parasite that infects other mammalian hosts aside from humans. In this study, a mathematical model is developed to describe the transmission of schistosomiasis in Agusan del Sur, Philippines and investigate control strategies that could lead to possible elimination of the disease. The model considers humans as definitive hosts, carabaos as reservoir hosts, and snails as intermediate hosts. Available schistosomiasis data from the Philippine Department of Health are utilized to estimate the transmission probability, contact rate between snails and humans, and infectivity from humans and carabaos to snails. Various intervention measures in mitigating the disease are explored under the framework of optimal control theory. The strategies include efforts to increase treatment coverage and compliance of mass drug administration; efforts to reduce humans and snails contacts by providing access to latrines and clean water, improving hygiene practices, targeted mollusciciding, etc.; and efforts to reduce carabaos and snails contact by using mechanized tractors. Results highlight the significance of an integrated approach and prioritizing control strategies considering resource constraints.