The Next Pandemic May Come From a Mosquito. Veterinarians Are Part of the Answer.

A major WHO-convened panel this week is asking the question that One Health has been building toward for years: can integrated animal, human, and environmental surveillance actually stop arbovirus outbreaks before they start?

On March 31, 2026, a multi-sectoral panel convened by WHO, PAHO, and WOAH gathered some of the most credible voices in global infectious disease to address a problem that has been growing for years without the urgency it deserves: the rising threat of zoonotic arboviruses in low and middle income countries, and whether the One Health framework can be operationalized quickly enough to do anything about it.

The panel — titled “One Health Lessons on Arboviruses for Stronger Preparedness in LMICs” — included Dr. Tracey McNamara of Western University of Health Sciences College of Veterinary Medicine, Dr. Chadia Wannous from WOAH, Dr. Sarah Cleaveland of the University of Glasgow, Dr. Lee Ching Ng from Singapore’s National Environmental Agency, and Dr. Gary Kobinger, moderated by Dr. Pierre Formenty. The combination of veterinary, environmental, epidemiological, and public health expertise on a single panel was itself a statement about what effective arbovirus preparedness actually requires.

For veterinary professionals, this is not someone else’s conversation.

What arboviruses actually are and why they are getting worse

Arthropod-borne viruses — arboviruses — are transmitted to humans and animals through the bites of infected arthropods, primarily mosquitoes and ticks. The category includes dengue, Zika, chikungunya, West Nile virus, yellow fever, Japanese encephalitis, and a growing list of emerging pathogens. Globally, arboviruses contribute to as many as 700,000 deaths each year, with dengue virus alone causing an estimated 390 million cases annually.

The trend line is moving in the wrong direction. Dengue cases have increased by 96 percent this decade compared to the previous one. Western equine encephalitis virus, which had effectively disappeared from South America after a 1988 outbreak, re-emerged in 2024. Vector species are establishing themselves in geographic areas where they previously did not exist, driven by climate change, urbanization, deforestation, and the movement of people and animals across borders.

Low and middle income countries bear a disproportionate share of the burden, where weak surveillance systems, inadequate containment infrastructure, and limited healthcare access allow rapid transmission — compounded by poverty, political instability, fragmented policies, and low public awareness. These are the settings where the human-animal-environment interface is most dynamic, and where the gap between what surveillance currently captures and what is actually circulating is widest.

The veterinary piece of the puzzle

Arboviruses do not emerge in humans first. They circulate in animal reservoirs — birds, rodents, non-human primates, domesticated livestock — before spilling over into human populations, often via the arthropod vector that bridges the two. The epizootic signal, the disease event in animals, frequently precedes the human epidemic by days, weeks, or longer.

This means veterinary surveillance is not a supporting role in arbovirus preparedness. It is an early warning system. A dead bird population with West Nile virus. Livestock seroprevalence indicating silent Rift Valley fever circulation. Unusual neurological presentations in horses consistent with emerging flavivirus activity. These are the signals that, if captured and shared across sectors in real time, create the possibility of acting before a spillover event becomes a human outbreak.

The challenge is that in most LMICs, animal health surveillance and human health surveillance operate in parallel but disconnected systems. Data does not flow between veterinary services, public health agencies, and environmental monitoring programs in the integrated way that early detection requires. The One Health framework exists precisely to close that gap — but as the March 31 panel acknowledged, existing framework and operational reality remain far apart in many of the settings that need integration most.

What the One Health Joint Plan of Action is trying to do

The One Health Joint Plan of Action, launched in 2022 by WHO, FAO, UNEP, and WOAH, established a structure for multisectoral collaboration on exactly these threats. The March 31 panel was convened within that framework, and its questions were specifically practical: what has actually worked in LMIC settings, what are the prerequisites for success, and what needs to happen next to build collaborative predictive epidemic intelligence systems that incorporate environmental, animal health, and human health data into a single decision-making framework.

The One Health framework fosters multisectoral collaboration for disease prevention and outbreak response, and integrating genomics, artificial intelligence, and ecosystem methods enhances early prediction of zoonotic threats. The surveillance infrastructure exists in some form in most countries. The integration of that infrastructure across sectors — human health, animal health, environmental monitoring, vector surveillance — is the piece that consistently fails to materialize at the speed and scale that emerging threats require.

The panel’s call was explicit: invest in collaborative, integrated surveillance. Not in parallel. Not when an outbreak is already underway. Before.

Why this matters for veterinarians in practice and in policy

The panel included Dr. Tracey McNamara, a veterinary pathologist whose career has been defined in part by exactly this problem. In 1999, McNamara identified the unusual bird deaths at the Bronx Zoo that turned out to be the first documented cases of West Nile virus in the Western Hemisphere. The signal was in the animals. It was a veterinarian who caught it. The human health system would have found it eventually — but later.

That story is not historical trivia. It is a template for what integrated arbovirus surveillance is supposed to do, and a reminder that veterinary professionals are not peripheral to global health preparedness. They are positioned at the spillover interface in a way that no other single professional group is.

The advocacy coming out of this panel — invest in collaborative surveillance, close the gap between animal health and human health data systems, build predictive intelligence that incorporates climate and environmental data alongside epizootic and enzootic signals — is an advocacy that the veterinary profession should be part of making loudly and consistently.

The next pandemic may come from a mosquito. The veterinarians paying attention to animal populations will be the ones who see it first.

The “One Health Lessons on Arboviruses for Stronger Preparedness in LMICs” panel was convened on March 31, 2026 by WHO, PAHO, and WOAH as part of the One Health Festival. The One Health Joint Plan of Action 2022-2026 is available at who.int.