IRCEB: The Evolution of a Parasite and its Recently Colonized Host

Auburn University, Auburn AL

Investigators

Abstract

0077804 Hill, Roberts & Edwards In 1994, a new songbird disease appeared in House Finches in backyards in Maryland. The severe eye and respiratory disease that was observed in these birds was caused by a bacterium, Mycoplasma gallicepticum (MG), which had apparently "jumped" from poultry. Since 1994, this disease has spread throughout eastern North America, killing an estimated 100 million House Finches. This study focuses on the co-evolution of this parasite and its newly colonized host. There has been steady decline in the incidence of mycoplasmosis in eastern House Finches since the epidemic year of 1995/6. This suggests that either finches have evolved genetic resistance to the disease, that MG has evolved reduced virulence, or that some combination of change in resistance and virulence has occurred. A combination of field observations, controlled infection experiments, and genetic analysis will be used to test for evolved genetic resistance to MG in finches and to test for change in virulence in the MG. While this research focuses on a disease that does not infect humans, much can be learned from a study of the interaction of a vertebrate population and a novel pathogen. We live in an age of globalization with new pathogens constantly being spread among populations of domestic animals, wildlife, and humans. Understanding the dynamic nature of interactions between parasites and hosts will provide critical information to help us deal with these new infectious diseases.