White-nose syndrome detected in bats over an extensive area of Russia

Background: Spatiotemporal distribution patterns are important infectious disease epidemiological characteristics that improve our understanding of wild animal population health. The skin infection caused by the fungus Pseudogymnoascus destructans emerged as a panzootic disease in bats of the northern hemisphere. However, the infection status of bats over an extensive geographic area of the Russian Federation has remained understudied. Results: We examined bats at the geographic limits of bat hibernation in the Palearctic temperate zone and found bats with white-nose syndrome (WNS) on the European slopes of the Ural Mountains through the Western Siberian Plain, Central Siberia and on to the Far East We identified the diagnostic symptoms of WNS based on histopathology in the Northern Ural region at 11 degrees (about 1200 km) higher latitude than the current northern limit in the Nearctic. While body surface temperature differed between regions, bats at all study sites hibernated in very cold conditions averaging 3.6 degrees C. Each region also differed in P. destructans fungal load and the number of UV fluorescent skin lesions indicating skin damage intensity. Myotis bombinus, M. gracilis and Murina hilgendorfi were newly confirmed with histopathological symptoms of WNS. Prevalence of UV-documented WNS ranged between 16 and 76% in species of relevant sample size. Conclusions: To conclude, the bat pathogen P. destructans is widely present in Russian hibernacula but infection remains at low intensity, despite the high exposure rate.