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White‐nose syndrome (WNS) has devastated populations of hibernating bats in eastern North America, leading to emergency conservation listings for several species including the previously ubiquitous little brown myotis (Myotis lucifugus). However, some bat populations near the epicenter of the WNS panzootic appear to be stabilizing after initial precipitous declines, which could reflect a selective immunogenetic sweep. To investigate the hypothesis that WNS exerts significant selection on the immunome of affected bat populations, we developed a novel, high‐throughput sequence capture assay targeting 138 adaptive, intrinsic, and innate immunity genes of putative adaptive significance, as well as their respective regulatory regions (~370 kbp of genomic sequence/individual). We used the assay to explore baseline immunogenetic variation in M. lucifugus and to investigate whether particular immune genes/variants are associated with WNS susceptibility. We also used our assay to detect 1,038 putatively neutral single nucleotide polymorphisms and characterize contemporary population structure, providing context for the identification of local immunogenetic adaptation. Sequence capture provided a cost‐effective, “all‐in‐one” assay to test for neutral genetic and immunogenetic structure and revealed fine‐scale, baseline immunogenetic differentiation between sampling sites <600 km apart. We identified functional immunogenetic variants in M. lucifugus associated with WNS susceptibility. This study lays the foundations for future investigations of rangewide immunogenetic adaptation to WNS in M. lucifugus and provides a blueprint for studies of evolutionary rescue in other host–pathogen systems.

Pseudogymnoascus destructans is the causative agent of an emerging infectious disease that threatens populations of several North American bat species. The fungal disease was first observed in 2006 and has since caused the death of nearly six million bats. The disease, commonly known as white-nose syndrome, is characterized by a cutaneous infection with P. destructans causing erosions and ulcers in the skin of nose, ears and/or wings of bats. Previous studies based on sequences from eight loci have found that isolates of P. destructans from bats in the US all belong to one multilocus genotype. Using the same multilocus sequence typing method, we found that isolates from eastern and central Canada also had the same genotype as those from the US, consistent with the clonal expansion of P. destructans into Canada. However, our PCR fingerprinting revealed that among the 112 North American isolates we analyzed, three, all from Canada, showed minor genetic variation. Furthermore, we found significant variations among isolates in mycelial growth rate; the production of mycelial exudates; and pigment production and diffusion into agar media. These phenotypic differences were influenced by culture medium and incubation temperature, indicating significant variation in environmental condition - dependent phenotypic expression among isolates of the clonal P. destructans genotype in North America.

ABSTRACT:Between 1993 and 1999, encephalitis caused by morbillivirus was diagnosed by immunohistochemistry and histology in six lynx (Lynx canadensis) and one bobcat (Lynx rufus) in the eastern Canadian provinces of New Brunswick and Nova Scotia. Five of the six cases in lynx occurred within an 11-mo period in 1996-97. A second bobcat with encephalitis caused by unidentified protozoa and a nematode larva also had immunohistochemical evidence of neurologic infection by morbillivirus. The virus was identified as canine distemper virus (CDV) by reverse transcriptase polymerase chain reaction and nucleotide sequencing in four of five animals from which frozen tissue samples were available, and it was isolated in cell culture from one of them. To our knowledge, this is the first report of disease caused by CDV in free-living felids in North America.