Pancreatic islet fibrosis in rock hyrax (Procavia capensis), Part 2: Pathology, immunohistochemistry, and electron microscopy

A RETROSPECTIVE STUDY OF PATHOLOGIC FINDINGS IN CAPTIVE ROCK HYRAX (PROCAVIA CAPENSIS) IN THE UNITED STATES

A retrospective examination of gross and histologic reports was performed to find common lesions in young and adult captive rock hyrax ( Procavia capensis ) from multiple zoo populations. One hundred and thirty-seven reports were analyzed from specimens that were submitted to Northwest ZooPath from 1997 to 2013. Histologic findings from necropsy and biopsy reports and causes of mortality only from necropsy reports were compiled to determine the most common findings. Within the study population, 41 (30%) were male, 62 (45%) were female, and the remainder (34, 25%) were of undetermined sex. Of the 111 necropsies, 87 (78%) died naturally, and 24 (22%) were euthanatized. There were 26 (19%) biopsies with no known status of the animal. The most frequent causes of death or reason for euthanasia were bacterial septicemia (n = 29, 21%) and degenerative cardiomyopathy (n = 29, 21%). The other most prevalent lesions were hemosiderosis (n = 55, 40%), pancreatic islet and interstitial fibrosis (n = 36, 26%), pneumonia of undetermined cause (n = 26, 19%), enteritis/colitis (n = 24, 18%), and renal tubular necrosis (n = 20, 15%). In many animals of this study population (n = 115, 84%), multiple lesions affecting multiple organs were found.

Pancreatic islet fibrosis in rock hyraxes (Procavia capensis), Part 1: Case histories, clinical pathology, and epizootiology

Two adult female rock hyraxes (Procavia capensis) at the Dallas Zoo were confirmed with spontaneous diabetes mellitus from 1997-2000, whereas a third animal with a similar clinical presentation never became hyperglycemic. The pancreas in all three animals showed pancreatic islet fibrosis (PIF). Retrospective examination of medical records for rock hyraxes acquired by this collection or born into it from 1991-2002 identified eight more animals affected with PIE All affected animals, including three males and eight females, were 1-7 yr of age and presented either with vague clinical signs of soft feces and rough hair coat or were acutely moribund or dead. Clinical pathology data was available for seven of the animals before onset of overt clinical signs and revealed inappropriate hyperglycemia in six, as well as elevated serum concentrations of creatine phosphokinase, amylase, and lipase in all seven animals. Pedigree evaluation did not support a familial pattern for PIE Review of the histopathology findings from nine other zoologic collections with rock hyrax deaths during the study period identified six institutions with 12 additional cases genetically unrelated to the incident collection. Histopathology and viral serology did not support an infectious cause. Analysis of serum anti-islet and anti-insulin antibodies did not suggest autoimmune disease, and none of the animals had known exposure to toxic substances. Limited nutritional analyses did not support a nutritional basis for the condition, and the cause for PIF remains unknown.