What is the One Health approach?
The comprehensive “One Health” approach aims to balance and optimize the health of humans, animals, and plants through their mutual dependence and connection to the ecosystems they inhabit.
The Joint One Health Action Plan (2022-2026) states: “This approach engages multiple sectors, disciplines, and communities at various levels of society to work together to promote well-being and neutralize threats to health and ecosystems, and, at the same time, addresses the collective need for clean water, energy, and air; safe and nutritious food; taking action on climate change; and contributing to sustainable development.”
The plan was developed by the World Health Organization (WHO), the Food and Agriculture Organization of the United Nations (FAO), the World Organization for Animal Health (WOAH, formerly OIE), and the United Nations Environment Programme (UNEP).
Health assessments of river dolphins in Colombia, as a contribution to the approach
Marine mammals have been recognized as guardians of the oceans, that is, they are indicators that can be used to measure the impact of different activities that can potentially affect animal and human health. For more information, we recommend reading Marine Mammals as Sentinel Species for Oceans and Human Health (Bossart, 2011).
In this sense, river dolphins, as creatures that share their habitats with humans and sometimes the same food source, fish, can be early warning indicators for potential public health risks, such as mercury contamination in rivers.
“In Colombia, we have conducted five health assessments of river dolphins, specifically with individuals of the Inia geoffrensis family, in the Amazon and Orinoquia regions,” explained Fernando Trujillo, scientific director of the Omacha Foundation.
The most recent assessment was conducted in February 2025 on the Orinoco River in the municipality of Puerto Carreño, as part of a project developed with the Dolphin Quest organization. The team of professionals, including veterinarians, ecologists, and biologists, took blood samples, tissue for mercury analysis, and swabs from the genital area and respiratory tract. Additionally, ultrasounds were performed to check the condition of the lungs and other organs.
María Jimena Valderrama Avella, a veterinarian at the Omacha Foundation, stated: “Through health assessments of river dolphins, we have better understood the interconnectedness between the health of humans, animals, and ecosystems. Through these health assessments, we seek to determine the health status of dolphin populations to promote conservation actions and deepen our understanding of aquatic ecosystems.”
Health assessments of river dolphins have been conducted in several South American countries where these cetaceans live, in the Amazon and Orinoco River basins, within the framework of the
South American River Dolphin Initiative (SARDI). The goal is to demonstrate the close relationship between river health and the biodiversity that inhabits these basins, including humans.
“During COP 16, concern about emerging diseases caused by contact between humans and wildlife became evident. Work like the one we conducted with river dolphins can generate early warnings to assess these potential pathogens,” Fernando Trujillo emphasized.
As part of the efforts to conserve river dolphins and strengthen local capacity, WWF Colombia supported two leaders from the Laguna Damas community, on the Guaviare River, in a veterinary assessment of dolphins in the Orinoco River.
This exercise is part of the research and monitoring efforts being undertaken to better understand the health status of dolphins and ensure their protection, in which veterinarians and biologists apply rigorous animal welfare protocols.
“Two leaders from Laguna Damas del Nare, a benchmark for nature tourism on the Guaviare River, participated in the health assessment carried out on the Orinoco River. Through these studies, we hope they can strengthen their ties with the territory,” explained Saulo Usma, Freshwater Ecosystem Specialist at WWF Colombia .
Before the visit, there were doubts and concerns among the communities of Laguna Damas del Nare regarding the procedures involving the temporary capture of dolphins for biological sampling. One of the leaders represented those who supported the research, while the other represented those who opposed it, fearing possible negative effects on the dolphins.
The field experience allowed them to observe firsthand how responsible management protocols are implemented and how dolphin welfare is prioritized throughout the process. At the end of the day, both expressed their agreement and satisfaction, noting that the experience helped clear up many doubts and fears regarding future interventions with dolphins in their territory.
This exchange is an example of the power of dialogue and learning between territories, which contributes to strengthening conservation based on scientific knowledge and community leadership.
Analysis of information and preliminary results
The results are currently being analyzed by a team of veterinarians from the National Marine Mammal Foundation (NMMF) and the Omacha Foundation, both of which are participating in the Operation Grace project. This is a long-term study, and the hope is to share the findings through scientific publications and other means so that the information reaches as many people as possible.
To date, the foundation has assessed the health of more than 40 dolphins and analyzed mercury concentrations in the tissues of more than 90 individuals.
“The most alarming records show dolphins with mercury levels of up to
36.89 mg/kg in tissue, a figure far higher than the limit established by the World Health Organization, which is 0.5 mg/kg ,” said Valderrama Avella.
Among the most significant findings, a female dolphin was found in the Amazon with a papilloma-like lesion —an abnormal growth of epithelial tissue from the upper layer of the skin—on her genital opening. Samples taken revealed the presence of parasitic cysts, indicating that the lesion was caused by protozoa.
This diagnosis was confirmed by a histopathological examination performed by veterinarian Ana María Henao of the Zoopath Veterinary Pathology Laboratory. The samples are currently undergoing genetic analysis to identify the causative species.
In addition, bacteria resistant to some antibiotics, such as Klebsiella sp. and Enterococcus, have been detected, representing a potential threat to public health.
“Klebsiella can be found in a variety of organisms. With these tests, the dolphins are telling us that this bacteria is present in the environment, but we don’t know the source, and that if this bacteria comes into contact with humans, it can cause diseases, usually respiratory ones, that are difficult to treat because they are resistant to some antibiotics,” explained Valderrama Avella, who concluded: “What we’re seeing in the dolphins may mirror what can happen to us. It’s possible that this bacteria isn’t causing any pathology in the dolphin, or perhaps it is; it depends on the individual’s immunity. For this reason, dolphins are sentinels of aquatic ecosystems.” These findings continue to be studied as part of the project’s long-term analysis.
Ultrasound recording of a gestating female river dolphin and ultrasound diagnosis of the dolphin. Photos: MV. Miguel Ortiz and Teresa Tomassoni.
Dr. Forrest Gomez, Director of Conservation Medicine and Operation GRACE at the National Marine Mammal Foundation, said, “At this moment, as we face a dual crisis—the sixth mass extinction and the emergence of global pandemics—these collaborations are more crucial than ever. River dolphins offer a unique perspective on the health of our freshwater ecosystems and the risks that can ultimately impact human health. Working together, across disciplines and borders, generates urgently needed knowledge that informs both conservation and public health actions while we still have time to make a difference.”
For his part, Cristian Von Reitze, CEO and Vice President of Conservation Engagement at
FIAA, said: “Once again, these partnerships show us that conserving the planet’s biodiversity depends on teamwork.”
These assessments are being carried out in collaboration with Dolphin Quest, the National Marine Mammal Foundation, the Ikozoa Biopark Foundation, the Corporation for Sustainable Development of the Southern Amazon (Corpoamazonía), the Orinoquia Regional Autonomous Corporation (Corporinoquia), WWF Colombia and the South American River Dolphin Initiative (SARDI), National Geographic and the Foundation for International Aid to Animals (FIAA).
