Meeting Abstract
Mycoplasma gallisepticum (MG) is a respiratory pathogen that induces swelling of the conjunctival mucous membrane lining the eye in domestic poultry and wild finches. Although experimental infection studies generally focuse on conjunctivitis as the primary physical symptom of interest, wild bird surveys suggest that many additional avian species function as carriers and potential reservoirs for MG spread. Due to a lack of obvious conjunctivitis symptoms, however, infection costs to these hosts have as of yet been largely unstudied. In 2017, 40% of wild-caught adult Eastern Bluebirds (Sialia sialis) in a Mississippi population tested positive for MG-specific Abs. To determine whether infection with MG is costly to this host species, I infected wild-caught, captive Eastern Bluebirds with a strain of MG cultured from a wild House Finch (Haemorhous mexicanus). Importantly, while no animals developed conjunctivitis symptoms over the course of the experiment, 12% of infected birds died before the experiment was complete. Following inoculation, 56% of birds seroconverted within 13 days, and MG was re-cultured from 25% of infected birds. In general, infection resulted in splenomegaly and significant weight loss. Infected birds that seroconverted were in better body condition and had higher levels of circulating corticosterone than those that did not seroconvert. Results strongly suggest that Eastern Bluebirds are not only common MG hosts in the wild, but that they suffer physiological and survival costs in response to infection with this common natural pathogen.
