Environmental reservoir dynamics predict global infection patterns and population impacts for the fungal disease white-nose syndrome

Abstract

Disease outbreaks and pathogen introductions can have significant effects on host populations, and the ability of pathogens to persist in the environment can exacerbate disease impacts by fueling sustained transmission, seasonal epidemics, and repeated spillover events. While theory suggests that the presence of an environmental reservoir increases the risk of host declines and threat of extinction, the influence of reservoir dynamics on transmission and population impacts remains poorly described. Here we show that the extent of the environmental reservoir explains broad patterns of host infection and the severity of disease impacts of a virulent pathogen. We examined reservoir and host infection dynamics and the resulting impacts of Pseudogymnoascus destructans, the fungal pathogen that causes white-nose syndrome, in 39 species of bats at 101 sites across the globe. Lower levels of pathogen in the environment consistently corresponded to delayed infection of hosts, fewer and less severe infections, and reduced population impacts. In contrast, an extensive and persistent environmental reservoir led to early and widespread infections and severe population declines. These results suggest that continental differences in the persistence or decay of P. destructans in the environment altered infection patterns in bats and influenced whether host populations were stable or experienced severe declines from this disease. Quantifying the impact of the environmental reservoir on disease dynamics can provide specific targets for reducing pathogen levels in the environment to prevent or control future epidemics.

Ten-year projection of white-nose syndrome disease dynamics at the southern leading-edge of infection in North America

“…Indeed, contact of bats with the contaminated environment (Linder et al 2011;Lorch et al 2013aLorch et al , 2013b in autumn has been shown to initiate the infection (Langwig et al 2015). Our findings further complement recent findings suggesting that persistence of high levels P. destructans in the environment result in widespread infections (Hoyt et al 2020). Although the primary method of spread of P. destructans and WNS is bat-to-bat (Raudabaugh & Miller 2013), under our parameter set only 1 in 10 is due to direct contact to an infectious individual during hibernation.…”

Possibility for reverse zoonotic transmission of SARS-CoV-2 to free-ranging wildlife: A case study of bats

“…The devastating impact of WNS on a diverse group of North American bats likely resulted from evolutionary isolation of the continent's bat fauna from other parts of the world for millions of years, despite other species of Pseudogymnoascus being present. Bats in both Europe and Asia can become infected by P. destructans but do not suffer mass mortality from WNS [36,37]. The bat fauna spanning the higher latitudes of North America (in the US and Canada) is composed almost entirely of endemic species belonging to the family Vespertilionidae.…”

“…Bats in both Europe and Asia can become infected by P . destructans but do not suffer mass mortality from WNS [ 36 , 37 ]. The bat fauna spanning the higher latitudes of North America (in the US and Canada) is composed almost entirely of endemic species belonging to the family Vespertilionidae.…”

Pseudogymnoascus destructans growth in wood, soil and guano substrates

“…The presence and types of fomites can influence dispersal of pathogens and disease dynamics 18 , 19 . Therefore, the role of substrates is significant in situations where viable pathogens from an environmental substrate can re-infect hosts or remain as an environmental reservoir 20 – 22 . Understanding the growth and survival of pathogens on environmental substrates is critical to inform management interventions that might sanitize or modify structures to reduce transmission risk 23 , 24 .…”