title: Novel Picornavirus Associated with Avian Keratin Disorder in Alaskan Birds.
abstract: Avian keratin disorder (AKD), characterized by debilitating overgrowth of the avian beak, was first documented in black-capped chickadees (Poecile atricapillus) in Alaska. Subsequently, similar deformities have appeared in numerous species across continents. Despite the widespread distribution of this emerging pathology, the cause of AKD remains elusive. As a result, it is unknown whether suspected cases of AKD in the afflicted species are causally linked, and the impacts of this pathology at the population and community levels are difficult to evaluate. We applied unbiased, metagenomic next-generation sequencing to search for candidate pathogens in birds affected with AKD. We identified and sequenced the complete coding region of a novel picornavirus, which we are calling poecivirus. Subsequent screening of 19 AKD-affected black-capped chickadees and 9 control individuals for the presence of poecivirus revealed that 19/19 (100%) AKD-affected individuals were positive, while only 2/9 (22%) control individuals were infected with poecivirus. Two northwestern crows (Corvus caurinus) and two red-breasted nuthatches (Sitta canadensis) with AKD-consistent pathology also tested positive for poecivirus. We suggest that poecivirus is a candidate etiological agent of AKD.
  
  
  
  Avian keratin disorder (AKD) is an increasingly common disease of wild birds. This disease, characterized by beak overgrowth, was first described in the late 1990s and has been spreading rapidly both geographically and in terms of host species affected. AKD decreases host fitness and can be fatal. However, the cause of the disease has remained elusive, and its impact on host populations is poorly understood. We found a novel and divergent picornavirus in 19/19 AKD-affected black-capped chickadees that we examined but in only 2/9 control cases. We also found this virus in 4 individuals of 2 other passerine species that exhibited symptoms consistent with AKD. Our data suggest that this novel picornavirus warrants further investigation as the causative agent of AKD.
authors.affiliation: Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, California, USA California Academy of Sciences, San Francisco, California, USA joe@derisilab.ucsf.edu MaxineZylberberg@gmail.com.
authors.forename: Maxine
authors.initials: M
authors.lastname: Zylberberg
authors.affiliation: U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, USA.
authors.forename: Caroline
authors.initials: C
authors.lastname: Van Hemert
authors.affiliation: California Academy of Sciences, San Francisco, California, USA.
authors.forename: John P
authors.initials: JP
authors.lastname: Dumbacher
authors.affiliation: U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, USA.
authors.forename: Colleen M
authors.initials: CM
authors.lastname: Handel
authors.affiliation: Department of Pathology, University of California, San Francisco, San Francisco, California, USA.
authors.forename: Tarik
authors.initials: T
authors.lastname: Tihan
authors.affiliation: Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, California, USA Howard Hughes Medical Institute, Chevy Chase, Maryland, USA joe@derisilab.ucsf.edu MaxineZylberberg@gmail.com.
authors.forename: Joseph L
authors.identifier: 0000-0002-4611-9205
authors.initials: JL
authors.lastname: DeRisi
mesh_terms: D000413:Alaska; D000818:Animals; D001502:Beak / Q000473:pathology*; D001715:Bird Diseases / Q000821:virology*; D001717:Birds; D019295:Computational Biology; D023061:Gene Order; D059014:High-Throughput Nucleotide Sequencing; D007633:Keratins / Q000378:metabolism*; D056186:Metagenomics; D010802:Phylogeny; D010849:Picornaviridae / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D010850:Picornaviridae Infections / Q000473:pathology / Q000662:veterinary* / Q000821:virology; D017385:Sequence Homology
chemical_list: D007633:Keratins