LB 21-183 - Infection intensity and survival varies with population and latitude in eastern newts exposed to Batrachochytrium salamandrivorans (Bsal)

Fungal pathogens are a growing threat to wildlife species globally. The emerging infectious disease, Batrachochytrium salamandrivorans (Bsal), is causing largescale die-offs of salamanders in Europe, and its invasion of North America could have disastrous consequences for salamander biodiversity. The eastern newt, Notophthalmus viridescens, is projected to be a key species determining Bsal transmission in North America because it is broadly distributed, abundant, and efficiently transmits Bsal in experimental settings. However, the extent to which eastern newt Bsal susceptibility varies across its species range is unknown. To examine intraspecific variation in susceptibility, we sampled eastern newts along a latitudinal gradient from Georgia to Vermont and quantified differential survival and infection intensity among populations. We found significant spatial heterogeneity in both survival probability and infection intensity, and a significant positive correlation between latitude and host survival. We further document significant variation in population genetic diversity, which may affect disease susceptibility across the range. Combined with a higher overall survival rate than has previously been reported in eastern newts, this variation in infection intensity and consequent mortality further refines our understanding of how the species may respond if and when Bsal invades the continent. Our results highlight the importance of examining susceptibility at fine spatial scales and identify populations that should be closely monitored given increased risk of Bsal mortality.