Amphibian pathogen Batrachochytrium dendrobatidis prevalence is correlated with season and not urbanization in central Virginia

Abstract

The global amphibian pathogen Batrachochytrium dendrobatidis (Bd) has been documented among many species throughout the United States, though cases of chytridiomycosis, the resulting disease, have occurred mostly on the west coast. We conducted a 2 yr survey of amphibians along an urban gradient in Virginia, USA, to test whether Bd prevalence among the amphibians sampled varied with urbanization and/or season. A total of 867 adult amphibians from 13 species and 49 tadpoles from 3 species were tested for Bd. The level of urbanization was based on surrounding human population density and anthropogenic disturbance. Bd was detected in 6 species. Bd prevalence was not found to vary with increases in urbanization, but did vary with season. Prevalence peaked in the spring at 45%, when temperatures were between 14 and 25°C, and dropped to below 2% in the autumn. Results from this survey support the hypothesis that Bd is endemic to the studied sites in Virginia. The present study, in concurrence with previous research by other investigators, shows that Bd is affected strongly by weather patterns. Urbanization, defined by human population density, appeared to have minimal impact on the prevalence of Bd. In addition to understanding the geographic distribution of Bd, it is important to understand factors that affect its prevalence if we are to develop approaches to managing this emerging disease. KEY WORDS: Batrachochytrium dendrobatidis · Amphibian disease · Season · UrbanizationResale or republication not permitted without written consent of the publisher

The Amphibian Chytrid Fungus, Batrachochytrium dendrobatidis, in Fully Aquatic Salamanders from Southeastern North America

“…For example, Gaertner et al [18] found an infection prevalence of 0.83 in cricket frogs ( Acris crepitans ) sampled in May from a site in central Texas. In Virginia, Pullen et al [19] found a peak prevalence of 0.45 across 13 semi-aquatic frog and salamander species. Sampling across seasons, Rothermel et al [17] found a prevalence of 0.18 in 12 species across four sites in Georgia, North Carolina, and South Carolina.…”

Infection dynamics in frog populations with different histories of decline caused by a deadly disease

“…Infection was generally higher at the cooler high-elevation sites ( Fig. 2; Table S2), which may promote Bd growth and transmission compared to the low-elevation sites (Retallick 2002;Woodhams and Alford 2005;Brem and Lips 2008;Pullen et al 2010;Sapsford et al 2013). Variation in the infection rate may also be driven by differences among sites in the microhabitat use and movement patterns of frogs (Rowley and Alford 2007;.…”

“…In the wild, Bd prevalence is often higher in cooler seasons and lower in warmer ones (Woodhams and Alford 2005;Brem and Lips 2008;Voordouw et al 2010;Whitfield et al 2012;Sapsford et al 2013). Bd is more prevalent at higher elevations, presumably because temperatures are cooler (Woodhams and Alford 2005;Brem and Lips 2008;Pullen et al 2010;Sapsford et al 2013). Temperature may influence susceptibility to infection and disease-induced mortality.…”

Predicting Microbiome Function Across Space Is Confounded by Strain-Level Differences and Functional Redundancy Across Taxa

“…Differences in an individual bacterial isolate's interactions with the environment and other microbes are also known to alter bacterial metabolite production (Daskin et al, 2014;Wolz et al, 2017;Medina et al, 2017a;Bird et al, 2018). Thus, another consideration is whether Bd is present and when is it most active, as changes in microbial community composition have been linked with the onset of Bd infection (Pullen et al, 2010;Longo et al, 2015;Clare et al, 2016;Varela et al, 2018). Specifically, Bd is more prevalent during seasons of moderate temperatures (between 17 and 25°C) and high precipitation.…”