The mountainous Cerro Castillo National Park, in the heart of Patagonia, is home to one of the world’s most endangered mammals – the huemul, or south Andean deer. The park contains 10% of the remaining species population.
Just 1,500 individuals are found across Chile and Argentina, with a subpopulation of the stocky deer discovered in Patagonia’s Cape Froward in 2025.
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But an often-fatal disease caused by the bacterium Corynebacterium pseudotuberculosis is spreading through the population in Cerro Castillo. Transmitted by domestic livestock, it causes abscesses in the lymph nodes and organs of the deer.
Now, a new rehabilitation centre for the species, run by the non-profit Rewilding Chile, has successfully treated its first patient for the disease. A young stag nicknamed Distraido underwent treatment and was later set free to rejoin his herd. Wildlife rangers will continue to monitor him.
“There’s very little knowledge of how to work with huemul deer in captivity,” explains Cristian Saucedo, wildlife director at Rewilding Chile, adding that the successful treatment and release of Distraido marks a significant milestone for the huemul.
“So, we can actually say that the successful treatment and release of Distraido marks a before and after in huemul conservation.”
Infections of Corynebacterium pseudotuberculosis are treated using antibiotics. This is a relatively straightforward procedure, but is difficult to implement in the wild as multiple captures, treatments and releases are needed.
The rehabilitation centre is part of The Huemul Corridor, a conservation strategy to reconnect populations throughout the southern Andes, which is undertaken by Rewilding Chile in collaboration with the Ministry of Agriculture, the National Forestry Service, and National Agricultural & Livestock Service since 2023.
