Meeting Abstract
Infectious diseases are a significant threat to the conservation of wildlife, but little is known about host-pathogen relationships in reptiles. The eastern indigo snake (Drymarchon couperi) is federally endangered due to the loss and degradation of its habitat in the U.S. Southeastern Coastal Plain. Wild populations are seasonally susceptible to ulcerative skin lesions, and these wounds provide increased opportunity for internal infections. Thus, there is a need to better understand the mechanisms of disease resistance in this species. Our study investigated plasma complement-based immunity of eastern indigo snakes against five bacterial species. We tested the hypothesis that snake complement proteins are less effective at killing the relatively virulent bacterium, Staphylococcus aureus, compared to opportunistic pathogens commonly isolated from reptiles. Plasma was collected from captive adult snakes (n = 9) and frozen at -80°C until analysis using an absorbance-based assay. We found that snake plasma killed high proportions of Escherichia coli (63.8% ± 3.8; CV=18%) and Pseudomonas aeruginosa (51.0 ± 7.1%, CV=42%). However, killing ability was lower and more variable against S. aureus (12.4 ± 5.0%, CV =90%), Salmonella arizonae (15.1 ± 5.8%, CV=95%) and Klebsiella oxytoca (2.0 ± 2.8%, CV=84%). Our findings suggest that eastern indigo snakes may be relatively more susceptible to infection with Salmonella and Klesbiella compared to other opportunistic pathogens. Further study is needed to understand how these differences in plasma killing ability influence morbidity and mortality in eastern indigo snakes.
