title: Pathologic findings in Western gray squirrels (Sciurus griseus) from a notoedric mange epidemic in the San Bernardino Mountains, California.
abstract: Notoedric mange, caused by the contagious, burrowing mite Notoedres centrifera, has been associated with several large-scale population declines of western gray squirrels (Sciurus griseus) and has been a significant obstacle to population recovery in Washington State where the species is listed as threatened. In 2009, residents and wildlife rehabilitators in the isolated San Bernardino Mountains of southern California reported a dramatic die-off of western gray squirrels, in what had been a previously dense and robust population. Individuals were observed suffering from abnormal neurologic behaviors (ataxia and obtundation) and severe skin disease. Full necropsy of five squirrels from the epidemic showed that all had moderate to severe infestation with mange mites and severe dermatitis characterized by hyperkeratosis, acanthosis, intralesional mites, intracorneal pustules and superficial bacteria. Mites from affected squirrels were evaluated by light and electron microscopy and identified as N. centrifera based on morphologic criteria. Additionally, the internal transcribed spacer-2 region of the mite was cloned, sequenced and accessioned in GenBank. The cause for the abnormal neurologic behavior was not confirmed on post-mortem examination. However, we hypothesize that mange can cause incoordination and obtundation as a result of malnutrition and dehydration, and intense pruritis may induce abnormal or erratic behavior that could be mistaken for neurologic signs. While we have characterized the severe impact this disease can have on individual animals, more work is needed to understand the impact on squirrel populations, particularly in view of the anecdotal reports of dramatic population declines that may take decades to recover.
authors.affiliation: Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
authors.forename: Nicole
authors.initials: N
authors.lastname: Stephenson
authors.affiliation: California Department of Fish and Wildlife, Wildlife Investigations Laboratory, 1701 Nimbus Road, Rancho Cordova, CA 95670, USA.
authors.forename: Pam
authors.initials: P
authors.lastname: Swift
authors.affiliation: California Department of Fish and Wildlife, P.O. Box 3222, Big Bear City, CA 92314, USA.
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Villepique
authors.affiliation: California Department of Fish and Wildlife, Wildlife Investigations Laboratory, 1701 Nimbus Road, Rancho Cordova, CA 95670, USA.
authors.forename: Deana L
authors.initials: DL
authors.lastname: Clifford
authors.affiliation: California Animal Health and Food Safety Laboratory System, 105 West Central Avenue, San Bernardino, CA 92408, USA.
authors.forename: Akinyi
authors.initials: A
authors.lastname: Nyaoke
authors.affiliation: California Animal Health and Food Safety Laboratory System, 105 West Central Avenue, San Bernardino, CA 92408, USA.
authors.forename: Alfonso
authors.initials: A
authors.lastname: De la Mora
authors.affiliation: California Animal Health and Food Safety Laboratory System, 105 West Central Avenue, San Bernardino, CA 92408, USA.
authors.forename: Janet
authors.initials: J
authors.lastname: Moore
authors.affiliation: Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
authors.forename: Janet
authors.initials: J
authors.lastname: Foley
keywords: Dermatitis; ITS-2; Internal transcribed spacer; Notoedres centrifera; Sciurid