Disease Modeling with Application to Parasite-borne Diseases

摘要

The study of the spread of diseases brings together many different questions, which include biological, epidemiological, clinical, and public health issues. System Dynamics provides a suitable framework formodeling diseases that enables one to bring together these questions in a convenient and manageable way.In the present paper, which is part of a program of work, we discuss models for the development and transmission of parasite-borne diseases, in particular, diseases which involve a primary host, a vector, and a parasite. We shall here regard humans as the primary ( or definitive) host and mosquitoes as the vector; the same method applies to other instances of the vector and the primary host. The models discussed here will be applied to different types of diseases. The data in this paper will refer primarily to the filariae.We first examine models for the biology of the disease in a single vector and in a single host, and for disease transmission between two humans through a vector.We then discuss a model for disease transmission in a population of vectors interacting with a population of hosts. Besides disease-free and infective states, the model allows for states of the host and the vector in which the host or vector has been exposed to the disease but is not yet infective. For the host, it also allows for recovered states.We examine the effect of different control strategies, including preventive measures as well as treatment for the disease. We also examine the possible effects of changes in the environment on the spread of the disease. We point out some of the complexities inherent in the biological processes, and the variability resulting from change in the values of the parameters in the system.