show Abstracthide AbstractIsopropylated triarylphosphate esters (ITP) are a group of organophosphate ester flame retardants that are components of several flame retardant mixtures, including Firemaster 550 (FM550). These mixtures are replacements for are known to cause various toxic effects in non-avian species, including neurological, developmental, and cardiac abnormalities. However, research on their effects in avian species, and particularly the potential for immunomodulatory effects have not yet been adequately studied. Impaired resistance to infection that may result from exposure to environmental contaminants can have direct or indirect implications on avian disease outbreaks. To gain insight into the relationship between emerging contaminants such as ITP and disease responses, we exposed American kestrel hatchlings to an ITP mixture and challenged them with polyinosinic : polycytidylic acid (Poly I:C), to simulate viral infection.