Meeting Abstract
Co-infecting pathogens interact with each other and their environment, the host, but foundational concepts from community ecology, such as priority effects, have rarely been used to understand co-infection. Here, we tested how the timing of infection with common and deadly amphibian pathogens impacts pathogen load, host growth, and survival; hypothesizing that larger time lags between pathogen exposures will lead to a greater competitive advantage for the initial pathogen. We infected post-metamorphic Cuban tree frogs (Osteopilus septentrionalis) with Ranavirus, the fungus Batrachochytrium dendrobatidis (Bd), a nematode Aplectana hamatospicula, or two of the three pathogens either sequentially or simultaneously. Prior infection with other pathogens altered Ranaviral and A. hamatospicula pathogen loads, significantly increasing Ranaviral pathogen loads for co-infected versus singly infected hosts and changing A. hamatospicula pathogen load depending on co-infecting pathogen. Time since previous infection was important for Bd infected hosts, but whether a longer time since infection increased or decreased loads depended on the co-infecting pathogen. Finally, infections with Bd and Ranavirus decreased host growth and survival. These results suggest that the order of infection can impact disease progression, and that some secondary infections can exacerbate consequences for hosts while others can ameliorate them.
