Kareiva 9321590 With few exceptions, diseases which are spread by ticks are maintained within wildlife populations, not human populations. A similar biology is seen for flea-borne diseases; for example, plague is maintained in wild rodent populations without the involvement of humans. Perhaps because these diseases are maintained in wildlife populations instead of human populations, little work has been done on the dynamics of these diseases and the flea or tick behaviors that influence the disease dynamics. In comparison, there is long history of work on the dynamics of human infectious diseases. Much of this work, however, assumes that transmission of disease occurs via random mixing of infected and susceptible individuals. In general this is not an accurate description of animal behavior, and it may be particularly inappropriate for describing the transmission of diseases spread by ectoparasites ( parasites, such as fleas and ticks that live on the exterior of their hosts). This research project combines both experimental and theoretical approaches to examine the effect of ectoparasite behavior on the dynamics of diseases spread by these parasites. The study system for this project is a species of rodent, Neotoma cinerea, the fleas, Orchopeas sexdentatus and Anomiopsyllus amphibolus, and the hard tick, Ixodes angustus in Western Washington. The work involves observations of flea and tick movement within the rodent populations and incorporates the observed behaviors into theoretical models to predict the effects on disease dynamics. The synthesis of field data and theoretical studies is especially important in epidemiology, because one often wants to identify quantitative attributes, such as thresholds for the spread of disease. By combining field studies with theoretical models, this work seeks to develop realistic models and estimates of numerical values of factors that strongly influence whether the disease is epidemic and the disease is spatial distribution.
