Avocado leaves, pits, skin, and possibly fruit contain a toxin called persin that has been associated with acute myocardial degeneration following ingestion in a variety of mammalian and avian species.1-4 Susceptibility to persin appears to be highly variable between species and there appear to be factors related both to the avocado and the animal that affect the susceptibility to toxicity. Ingestion of persin targets heart and lactating mammary gland and results in clinical symptoms that vary with species but include a sudden onset of weakness, which may progress rapidly to death.4 Five of 13 aye-aye (Daubentonia madagascariensis) housed at the Duke Lemur Center became ill within a few hours of each other and within the next 15 h four of the five had died. All five of the ill aye-ayes developed pericardial effusion and had been fed avocado fruits (Persea americana) the day prior to death from acute myocardial degeneration. The four animals that died all had stomach contents containing persin. A review of necropsy results from unexplained acute aye-aye deaths over the past 20 yr uncovered an additional five cases at four other institutions with necropsy and histopathology findings strongly suggestive of avocado toxicity. The unusual factor in the present case was a history of long standing avocado ingestion in the colony without morbidity/mortality, suggesting a co-factor. The aye-aye is the first reported primate avocado toxicity. The authors speculate that catecholamine effects of stress on the heart may turn out to be the as-yet unidentified modifier of toxicity.
The authors would like to thank: Cecil F Brownie, DVM, PhD for his wisdom and knowledge in toxicology and life; the Centers for Disease Control and Preventions for its support reviewing and confirming histopathology; the Duke Laboratory Animal Resource veterinarians for their input and assistance; and the Prosimian Taxon Advisory Group for distributing information to all institutions world-wide with captive aye-aye.
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