Mathematical models in epidemiology : simulating chagas disease transmission and evaluating the control measures

Abstract

Chagas disease is one of the 20 Neglected Tropical Diseases, being an important health problem in Latin America, causing around 10,000 deaths due to complications linked to the disease, and affecting around 8 million people worldwide, according to World Health Organization (WHO). The main route of transmission is by the triatomine bug feces. Other transmission routes are blood transfusion and organ transplantation from infected individuals, from mother to child, which is called congenital transmission, by laboratory accident, and by consumption of contaminated food or drink. In the present work, two compartmental deterministic models for Chagas disease transmission were used. This kind of model is based on a system of differential equations which is integrated numerically using computational software. The first model deals only with humans, without the vector presence, considering transmission by congenital and blood transfusion routes. The second one simulates a community with the vector presence in two environments, peridomicile and intradomicile, as well as the presence of the human, domestic animals, competent and non-competent hosts. Simulations were performed to assess different scenarios regarding control strategies. The results of model simulations show that even without the vector presence the disease can be maintained for a long time in a population due to congenital and blood transfusion transmission, the detection and treatment of infected individuals are extremely important in order to avoid future complications dues to the disease, and control measures should be reinforced and maintained in order to reduce the number of new cases. In case of interruption of those controls measures, the simulations show that the system returns very quickly to scenarios similar to that where control measures are not applied.