LINEAGE-ASSOCIATED IRON OVERLOAD IN CAPTIVE FEMALE AMARGOSA VOLES (MICROTUS CALIFORNICUS SCIRPENSIS)

Area of Science:

• Veterinary Pathology
• Conservation Genetics
• Mammalian Physiology

Background:

• Iron storage disease (hemochromatosis) poses a threat to captive breeding programs for endangered species.
• Two cases of hemochromatosis were identified in a colony of Amargosa voles (Microtus californicus scirpensis).
• Understanding risk factors is crucial for managing this vanishing species.

Purpose of the Study:

• To investigate the prevalence of excessive hepatic iron accumulation in Amargosa voles.
• To identify risk factors influencing iron overload in this captive colony.
• To inform management decisions for the conservation of Amargosa voles.

Main Methods:

• Mass spectroscopy was used to quantify hepatic iron content in affected and unaffected voles.
• Prussian blue staining of liver tissue identified ferric iron accumulation.
• Automated image analysis quantified iron staining, and pedigree analysis examined lineage.
• A study set of 45 voles was analyzed for iron accumulation and risk factors (age, sex, parity, lineage, diet, housing).

Main Results:

• Six voles exhibited excessive hepatic iron accumulation; all were female.
• Female voles had significantly higher hepatic iron levels than males.
• Age, diet, and housing were not identified as risk factors.
• Lineage was a significant risk factor, with five affected voles related to a single founder.
• Parity was not associated with iron accumulation.

Conclusions:

• Excessive hepatic iron accumulation in Amargosa voles is associated with female sex.
• The condition appears to be potentially heritable, linked to specific lineages.
• These findings are critical for the management and propagation of this endangered species.