Modeling Chagas disease vector infection prevalence: incorporating life history characteristics and community composition

Authors: Carolina Cabrera, Nicole L. Gottdenker

Abstract Multihost vector-borne pathogens play an important role in human and veterinary public health worldwide, and understanding factors that drive their transmission is critical to the development of vector-borne disease prevention and control. Two potentially important drivers of multihost vector-born pathogen transmission are 1) the community composition of reservoir host species that come in contact with the vector in a particular habitat, and 2) the life history characteristics of reservoir hosts. One of the most important multihost vector-borne pathogens in the Americas, infecting over 10 million people, is the protozoan parasite Trypanosoma cruzi, the cause of Chagas disease in humans. T. cruzi circulates between wild and domestic animal reservoirs and humans, and is transmitted by a triatomine vector. The objective of this study is to develop a mathematical model that attempts to incorporate biological realities of Trypanosoma cruzi transmission between reservoir hosts and a triatomine vector. Specifically, we evaluate the Chagas disease system in Panama, consisting of a wide range of mammalian reservoir hosts and the main vector Rhodnius pallescens. We link a deterministic SI model for pathogen transmission in the vector with an SI model that describes host community transmission, incorporating host community structure and host life history characteristics, as well as hosts that have been previously infected with T. cruzi, but have developed partial immunity and are less competent reservoirs. Using field and molecular blood meal data, and values from the literature, we calculate a reservoir potential index for the different habitats within this Chagas disease system and evaluate the degree to which changes in reservoir community structure and life history characteristics impact vector infection prevalence.

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