Primates as Sentinels: Advancing Community-Based Yellow Fever Surveillance in Colombia

Colombia has consolidated its experience in Community-Based Surveillance (CBS) and stands out for its innovation in epidemic management. The Pan American Health Organization/World Health Organization (PAHO/WHO) has recognized this experience and promoted exchanges with countries like Brazil, Ecuador, and Paraguay within the PROTECT project.

Bogotá, 3 April, 2025. The night before, residents of San Isidro, in Cunday (Tolima), reported the presence of a dead howler monkey among the cocoa trees. This finding represented a new alert in a region already affected by a yellow fever outbreak. PAHO/WHO has worked in the area to capture vector mosquitoes and document geospatial findings, strengthening community surveillance.

In Tolima, the outbreak has been particularly severe, with 31 confirmed cases and 13 deaths in six months, according to the National Institute of Health (INS), representing a lethality rate of 41.9%. PAHO/WHO has trained over 100 community members to manage deceased primates, which is crucial for identifying transmission zones and planning preventive measures. The surveillance of non-human primates (NHP) is key in the early detection of the virus, as their mortality can indicate the active circulation of the virus and alert them to the risk for humans.

Primates as Sentinels: A Key Advance in Community-Based Surveillance of Yellow Fever in Colombia Colombia hosts a mission of delegates from the Ministries of Health of Ecuador and Paraguay to exchange knowledge and experiences in Community-Based Surveillance. This initiative aims to enhance early disease detection and response to health emergencies through collaborative learning and expertise sharing.

"Community-based surveillance, which includes the surveillance of primates as sentinels, represents an advance in public health strategies. It reinforces control measures such as vaccination and entomological control. It allows for effective communication with the community, avoiding panic and promoting their participation in prevention," - Mauricio Cerpa, international health emergency advisor at PAHO/WHO.

Colombia shares its best practices in CBS.
Colombia's Community-Based Surveillance (CBS) strategy, led by the National Institute of Health (INS), operates in 29 municipalities with over 665 leaders and 70 active community members, strengthening early detection and response to health emergencies. Enhanced by initiatives like the Community-Based Epidemiological Surveillance Network (ReVCom), CBS connects community agents and managers to address public health risks in vulnerable populations, including indigenous and rural communities. Collaboration between national and international entities has optimized responses to outbreaks like dengue, leveraging active community participation in surveillance and vector control.

The Colombian model is replicable in other countries, standing out for its community focus and flexibility to adapt to different contexts. PAHO has recognized this experience and facilitated exchanges with Brazil, Ecuador, Paraguay, and Bolivia within the PROTECT project, funded by the Pandemic Fund. During these visits to Colombia, the INS presented the SIVIGILA surveillance system, the early warning system, and the Public Health Emergency Operations Center (COE-SP). The visitors were immersed in various rural areas, such as Magdalena and Putumayo, to learn firsthand about implementing these strategies at the local and community levels. This initiative aims to strengthen surveillance and laboratory capacity in border regions of South America, benefiting over 2.4 million people.

In the framework of these exchanges, representatives from the Ministries of Health of Paraguay and Ecuador learned about the risk management and early warning model led by the INS, exchanged knowledge, and applied community-based approaches in Putumayo and Guainía. Brazil's experts visited Tolima to exchange knowledge on managing the yellow fever outbreak, promoting early notification of mortality in non-human primates (NHP), and ensuring its articulation with epidemiological and vector surveillance.

The experience in Tolima has shown that community surveillance strengthens the early detection of outbreaks and empowers communities to protect their health. By expanding this methodology to new territories, Colombia reinforces its capacity to respond to health emergencies and consolidates itself as a regional benchmark in innovative epidemiological surveillance strategies.

Each early alert represents an opportunity to save lives and prevent epidemics, demonstrating that public health is a collective effort where the community is the first link in protection.