Emergence Of White-nose Syndrome Research Articles

The skin I live in: Pathogenesis of white-nose syndrome of bats.

The emergence of white-nose syndrome (WNS) in North America has resulted in mass mortalities of hibernating bats and total extirpation of local populations. The need to mitigate this disease has stirred a significant body of research to understand its pathogenesis. Pseudogymnoascus destructans, the causative agent of WNS, is a psychrophilic (cold-loving) fungus that resides within the class Leotiomycetes, which contains mainly plant pathogens and is unrelated to other consequential pathogens of animals. In this review, we revisit the unique biology of hibernating bats and P. destructans and provide an updated analysis of the stages and mechanisms of WNS progression. The extreme life history of hibernating bats, the psychrophilic nature of P. destructans, and its evolutionary distance from other well-characterized animal-infecting fungi translate into unique host-pathogen interactions, many of them yet to be discovered.

Contact-independent exposure to Rhodococcus rhodochrous DAP96253 volatiles does not improve the survival rate of Myotis lucifugus (little brown bats) affected by White-nose Syndrome.

Since the emergence of White-nose Syndrome, a fungal disease in bats, caused by Pseudogymnoascus destructans, hibernating populations of little brown bats (Myotis lucifugus) have declined by 70-90% within P. destructans positive hibernacula. To reduce the impact of White-nose Syndrome to North American little brown bat populations we evaluated if exposure to volatile organic compounds produced by induced cells from Rhodococcus rhodochrous strain DAP96253 could improve the overwinter survival of bats infected by P. destructans. Two simultaneous field treatment trials were conducted at natural hibernacula located in Rockcastle and Breckinridge counties, Kentucky, USA. A combined total of 120 little brown bats were randomly divided into control groups (n=60) which were not exposed to volatile organic compounds and treatment groups (n=60) which were exposed to volatile organic compounds produced by non-growth, fermented cell paste composed of R. rhodochrous strain DAP96253 cells. Cox proportional hazard models revealed a significant decreased survival at the Rockcastle field trial site but not the Breckinridge field site. At the Breckinridge hibernacula, overwinter survival for both treatment and control groups were 60%. At the Rockcastle hibernacula, Kaplan-Meier survival curves indicated significantly increased overwinter survival of bats in the control group (43% survived) compared to the treatment group (20% survived). Although complete inhibition of P. destructans by volatile organic compounds produced by induced R. rhodochrous strain DAP96253 cells was observed in vitro studies, our results suggest that these volatile organic compounds do not inhibit P. destructans in situ and may promote P. destructans growth.

Mobile Bat Acoustic Routes Indicate Cavity-Roosting Species Undergo Compensatory Changes in Community Composition Following White-Nose Syndrome

Emerging pathogens can cause mass mortalities in susceptible species. High host mortality, in turn, can alter species composition, community structure and function. White-nose syndrome (WNS) is an emerging wildlife disease introduced to North America that has decimated millions of cave-dependent bats. For areas affected by WNS, there have been reports of community compositional changes, but compensatory changes to species composition following WNS has only been suggested, not reported. To determine if compensatory changes to species composition occur following WNS, we used seven years of data from statewide citizen science mobile bat acoustic routes initiated by the Ohio Division of Wildlife in 2011. We hypothesized that migratory bat abundance increased and cave-dependent bat abundance decreased following the emergence of WNS in the study period (2011–2017). Our hypothesis was based on the higher susceptibility of cave-dependent bats than migratory bats to infection and WNS mortality. We used two sets of models to identify abundance trends of each species found in Ohio and species grouped by wintering and roosting behaviors that are putatively important to changes in species composition post-WNS. Following WNS, we found a compensatory change in species in summer months from cave-dependent, cavity-roosting species (Myotis species and Eptesicus fuscus) to migratory, cavity-roosting species (Nycticeius humeralis and Lasionycteris noctivagans). However, for species that roost in foliage in the summer, we did not detect an increase in migratory species (Lasiurus borealis and Lasiurus cinereus) paired with a decrease in cave-dependent species (Perimyotis subflavus). The observed post-WNS trends in bat populations could suggest shifts in bat species composition in other areas where WNS is established.

Balancing the Costs of Wildlife Research with the Benefits of Understanding a Panzootic Disease, White-Nose Syndrome.

Additional ethical issues surrounding wildlife research compared with biomedical research include consideration of the harm of research to the ecosystem as a whole and the benefits of conservation to the same species of animals under study. Research on white-nose syndrome in bats provides a case study to apply these considerations to determine whether research that harms ecosystems under crisis is justified. By expanding well-established guidelines for animal and human subjects research, we demonstrate that this research can be considered highly justified. Studies must minimize the amount of harm to the ecosystem while maximizing the knowledge gained. However, the likelihood of direct application of the results of the research for conservation should not necessarily take priority over other considerations, particularly when the entire context of the ecologic disaster is poorly understood. Since the emergence of white-nose syndrome, researchers have made great strides in understanding this panzootic disease and are now in a position to utilize this knowledge to mitigate this wildlife crisis.

Prey Consumed by Bats Across Central Appalachia Prior to Detection of White-nose Syndrome

ABSTRACT An understanding of prey consumption patterns across bat species is lacking in a community context across Appalachia. This region of North America is of immediate importance to conservation efforts given the emergence of White-nose Syndrome (WNS). We report on prey consumed by 187 bats captured in mist nets from 2006 to 2008 in Kentucky, Ohio, Tennessee, and West Virginia. Results indicate that consumption of arthropod groups varies among bat species and geographic location, but Coleoptera and Lepidoptera were important dietary items across this predator assemblage. We attribute the variation observed across bat species to be due to differences in ecomorphology and foraging strategies. This study provides baseline data for investigating feeding patterns following impacts from WNS in the Central Appalachian region.

TEMPORAL VARIATION IN BAT WING DAMAGE IN THE ABSENCE OF WHITE-NOSE SYNDROME

White-nose syndrome (WNS) is an emerging infectious wildlife disease that has killed more than 5 million bats in the eastern United States since its discovery in winter 2006. The disease is associated with a cold-adapted fungus that infects bats during winter hibernation. Wing damage has been documented in bats with WNS and could become a useful screening tool for determining whether samples should be submitted for testing. However, because there are no historic records, to our knowledge, of wing damage before the emergence of WNS, it is unknown what types of grossly observable wing damage, if any, are specific to WNS. To address this knowledge gap, we inspected the wings of 1,327 bat carcasses collected in Illinois from 2005 and 2008-2010, then used Akaike information criterion to evaluate generalized linear models of the frequencies of different categories of wing damage using age, sex, year, and season as predictors in big brown bats (Eptesicus fuscus). Wing discoloration was best predicted by year and season. There were no clear predictors for other categories of wing damage. We found that about one-fourth of big brown bats surveyed from this presumptive WNS-negative sample had moderate or severe wing damage. We encourage further studies of the relationship between WNS and wing damage to better understand which categories of damage are to be expected in the absence of WNS in susceptible species.

Bat White-Nose Syndrome in North America

In 2007 bats in eastern North America began dying in unprecedented numbers from a previously undocumented disease, now called white-nose syndrome (WNS). Although the ecological and economic impacts of this disease are not fully elucidated, this severe loss of insectivorous bats threatens decreased crop yields, forest defoliation, and a rise in insect-borne diseases. The recent emergence of WNS in bats of eastern North America, its rapid spread, and the severity of the outbreak highlight the importance of wildlife disease as an integral component of ecosystem health.

Bats

Bats

Use of Temperature-Sensitive Transmitters to Monitor the Temperature Profiles of Hibernating Bats Affected with White-Nose Syndrome

In temperate ecosystems, hibernation allows bats to survive long periods of limited prey and water availability during colder months. Despite the extended amount of time some bats spend in hibernation, researchers have only recently been able to study the hibernation ecology of bats under natural conditions. With the emergence of white-nose syndrome (WNS), a mysterious disease presently killing large numbers of bats during the hibernation period in the northeastern United States, expanding our knowledge of hibernation ecology and natural history has become more crucial. To collect such data, we used temperature-sensitive radio transmitters and data loggers to monitor the skin temperatures (Tsk) of 6 bats (5 Myotis lucifugus [Little Brown Bat], and 1 Myotis septentrionalis [Northern Long-eared Bat]) hibernating in Mount Aeolus Cave, VT in late winter 2008. We recorded Tsk every 14 minutes for the life of the transmitters. We were able to monitor Tsk from near ambient temperatures to above 30 °C Arousals occurred immediately before the signals were lost and at a time of increased numbers of bats observed on the landscape, thereby suggesting the emergence (and subsequent death) of bats. Our observations provide first data on the hibernating ecology of WNS-affected bats under natural conditions.