Abstract

Captive Egyptian fruit bats (Rousettus aegyptiacus) are one of many species that frequently develop iron storage disease within zoological collections and laboratory colonies. Previous studies have identified a high incidence of iron storage disease in this species.^1,2 The goals of this study were to determine the complete tissue distribution of iron storage in captive adults and the incidence of other pathologic lesions, including neoplasia and infectious diseases, which may be directly or indirectly related to iron overload. In this multi-institutional study, histologic sections from over 100 adult Egyptian fruit bats of both sexes were evaluated with hematoxylin & eosin and Prussian blue staining for iron. Histologic evaluation of iron was based on the grading scheme in Farina et al. (2005) that was proven to significantly correlate with tissue iron concentrations. Additionally, sections of liver and heart tissue were also stained with Masson’s trichrome stain to evaluate for the presence and/or severity of fibrosis. Liver and spleen consistently had the largest amount of iron, but iron was also detected in the gastrointestinal tract, renal tubules, pulmonary interstitium, choroid plexus, and reproductive organs. Hepatic and extrahepatic neoplasia was also identified in iron overloaded bats. Hepatocellular carcinomas were the most common neoplasm, followed by cholangiocarcinoma. Metastatic neoplasms with no hepatic involvement were also identified including a carcinosarcoma, heart-based neuroendocrine mass, and a urinary transitional cell carcinoma. Cardiomyopathy was identified in multiple iron overloaded bats. Hepatic abscesses occurred in association with increased iron storage in multiple cases, although a common etiologic agent was not identified.

Literature Cited

1.  Crawshaw G., S. Oyarzun, E. Valdes, and K. Rose. 1995. Hemochromatosis (iron storage disease) in fruit bats. Proc of the Nutrition Advisory Group 136–47.

2.  Farina L.L., D.J. Heard, D.M. LeBlanc, J.O. Hall, G. Stevens, J.F. Wellehan, and C.J. Detrisac. 2005. Iron storage disease in captive Egyptian fruit bats (Rousettus aegyptiacus): relationship of blood iron parameters to hepatic iron concentrations and hepatic histopathology. J Zoo Wildl Med. 36(2):212–21.