Association Between Stress and Bilateral Symmetrical Alopecia in Free-Ranging Formosan Macaques in Mt. Longevity, Taiwan

The study explored the relationship between stress and bilateral symmetrical alopecia in Formosan macaques, using a sample size of 41 individuals (10 with alopecia and 31 without). Researchers measured fecal glucocorticoid metabolite (FGM) concentrations, specifically 11ß-hydroxyetiocholanolone, to assess stress levels and performed histopathological evaluations of skin biopsies. They found that macaques with alopecia had significantly higher FGM concentrations (2.02 µg/g) compared to those without (1.41 µg/g), and also displayed lower follicular densities and anagen to catagen/telogen ratios. The study concluded that stress is likely a primary factor in the development of alopecia in these macaques and that the health and welfare of the population could be affected, with potential implications for zoonosis risk due to human-macaque interactions.