Immune System Changes and Susceptibility to Disease in Birds Exposed to Environmental Contaminants

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Disease dynamics in wildlife are commonly related to changes or increases in environmental stressors that are placed upon an animal. Environmental pollutants are known to affect the immune system of wildlife, resulting in impaired resistance to infection and potential increases in disease outbreaks.

In collaboration with: Jill Jenkins, Ph.D USGS Wetland and Aquatic Research Center; Julia Lankton, DVM, USGS National Wildlife Health Center; Christine Custer, PhD, USGS Upper Midwest Science Center.

The Challenge: Exposure to contaminants can alter immune responses in birds, thereby affecting animal fitness and ability to prevent infection and disease. However, little is known about the immunotoxicity of emerging chemicals of concern, such as replacement flame retardants. These compounds are being found with greater regularity in wild birds and their eggs, due to increasing levels in the environment. Our research will be addressing the following question: Does exposure to elevated levels of contemporary or newly emerging contaminants cause immunotoxic or other effects in birds and make the birds more susceptible to disease?

The Science: We will be using a combined laboratory and field approach to evaluate effects of emerging contaminants on the immune system of birds and their response to disease challenges. We are examining molecular (gene expression), cellular (immune cell biomarkers), biochemical (hormones, oxidative stress indicators), histological and physiological indicators of immune changes in American kestrels (Falco sparverius) and tree swallows (Tachycineta bicolor) to better understand the health and disease susceptibility of birds in contaminated locations.

The Future: Understanding whether birds in more highly contaminated areas are more susceptible to disease compared to those in seemingly less perturbed areas is vital for evaluating the spread of avian diseases and for understanding the hazards (if any) posed by emerging contaminants on wildlife.