July 2025
When three monkeys (a howler, a white-faced monkey, and a spider monkey) were found dead in a forested area of Colombia’s Putumayo department, what might have previously gone unnoticed became an early warning sign that triggered a swift, coordinated response to contain a yellow fever outbreak. This time, the difference was knowledge.
"Thanks to the training we received on proper sample collection in primates, we were able to detect a yellow fever outbreak after discovering three dead monkeys at the same time,” said Wilder Pérez, from the Putumayo Health Secretariat’s Vector-Borne and Zoonotic Disease Program. “Without that knowledge, the animals might have been buried without analysis — and we would have missed a critical opportunity to act.”
Wilder had participated several months earlier in a regional workshop on epizootic and vector surveillance, organized with technical support from the () under the PROTECT initiative, funded by the Pandemic Fund. During the training, health teams were taught how to safely collect samples from wildlife, conduct vector surveillance, and coordinate across sectors.
The workshop, held in Tolima—another key department in Colombia’s current yellow fever response—proved crucial for enabling the Putumayo team to act swiftly when the first signs of the virus emerged.
The training paid off. Once the dead monkeys were reported, immediate measures were taken — vaccinating environmental workers, conducting entomological studies, and analyzing the affected area. As a result, the surveillance system not only confirmed the presence of the virus, but also prevented its spread to nearby urban areas.
Tolima, for its part, is facing the most severe outbreak recorded in the country outside the Amazon region. In this department alone, from late 2024 through June 28, 2025, 95 human cases of yellow fever have been confirmed, including 35 deaths.
