2 - Epidemiology of Vector-Borne Diseases

Abstract

This chapter introduces the concepts that are needed to understand the epidemiology of vector-borne diseases. “Epidemiology” deals with the natural history and spread of diseases, within human and animal populations. Vector-borne diseases consist minimally of a triad that includes an arthropod vector, a vertebrate host, and a parasite. The spread of pathogens by arthropods is especially complex because, in addition to interactions between the vertebrate host and the parasite, an arthropod is required for transmission of the parasite to uninfected hosts. Environmental factors, such as temperature and rainfall, impact these processes by affecting the rate of parasite maturation within the arthropod host, as well as arthropod abundance in time and space. A complete understanding of the epidemiology of arthropod-borne disease requires knowledge of the ecology, physiology, immunology, and genetics of parasite, arthropod, and vertebrate host populations and their interaction with the environment. Blood feeding by the vector typically brings parasite, vector, and vertebrate host together in time and space and ultimately, is responsible for the transmission of parasites from infected to susceptible vertebrate hosts.