Exploring the historical, new, and reemerging links between human and animal health through the One Health framework
In the cold winter of 1952, a mysterious phenomenon unfolded in Minamata, Japan. Cats began stumbling, convulsing, and dancing in the streets—a bizarre neurological disorder that baffled residents. Only years later would the world understand that these "dancing cats" were the first sentinels of an environmental disaster, warning of deadly methylmercury contamination in the local waters that would eventually claim thousands of human lives 1 .
This eerie episode reveals a fundamental truth we're only beginning to fully appreciate: human health is inextricably woven together with the health of animals and our shared environment.
Approximately 75% of emerging infectious diseases originate from animals, highlighting the critical connection between human and animal health 3 8 .
Ancient civilizations recognized that certain diseases could pass between species, often attributing epidemics to animal influences.
"From the devastating pandemics of COVID-19 to the steady threat of antimicrobial resistance, the connections between species have never been more apparent—or more consequential."
The connection between human and animal health is not a new discovery. Ancient civilizations recognized that certain diseases could pass between species, often attributing epidemics to animal influences or supernatural forces 1 . What modern science has revealed is the astonishing depth of this interconnection.
We share hundreds of illnesses with animals—known as zoonotic diseases—creating a complex web of health relationships that transcend species boundaries 1 .
This biological intimacy means that disturbances impacting animal health frequently ripple through human populations, and vice versa. When the European Commission invested €238 million between 2007 and 2011 in alternatives to animal testing, the benefits extended far beyond the cosmetics industry to influence broader medical research 2 .
Hundreds of illnesses are shared between humans and animals
Early recognition of disease transmission between species, with various cultural explanations for epidemics.
"Dancing cats" served as early warning of methylmercury contamination affecting humans.
European Commission invests €238 million in alternatives to animal testing, benefiting both human and animal health research 2 .
Formalization of the One Health approach as a collaborative framework for addressing shared health threats.
The One Health concept represents a paradigm shift in how we approach disease prevention, detection, and response. It's an integrated, unifying approach that aims to sustainably balance and optimize the health of people, animals, and ecosystems 6 .
This isn't merely an academic theory; it's a practical framework being implemented worldwide through collaborations between organizations like the World Health Organization, the World Organisation for Animal Health, and national centers for disease control 6 7 .
One Health recognizes that professionals in human health, animal health, environment, and other relevant sectors need to communicate, collaborate, and coordinate activities to effectively address health challenges 7 .
Growing populations are expanding into new geographic areas, bringing people into closer contact with wild and domestic animals 7 .
Climate change, deforestation, and intensive farming practices disrupt habitats and create new opportunities for disease transmission 7 .
The movement of people, animals, and animal products through international travel and trade allows diseases to spread rapidly across borders 7 .
The most visible connection between human and animal health lies in the realm of zoonotic diseases—infections that naturally transmit between vertebrates and humans 1 3 . The statistics are staggering: not only do 75% of emerging human infectious diseases originate from animals, but approximately 60% of all known human infectious diseases can be transmitted by animals 8 .
| Disease | Animal Connection | Impact and Notes |
|---|---|---|
| Avian Influenza | Birds, particularly poultry | Present on every continent; resulted in loss of over 300 million birds since 2005 4 |
| COVID-19 | Wildlife (exact species unknown) | Led to millions of human deaths and trillions in global economic losses 6 |
| Rabies | Primarily dogs | 100% preventable through vaccination; mass vaccination campaigns aiming for 2030 elimination 4 |
| Lyme Disease | Ticks that feed on various mammals | Example of vector-borne disease whose spread is influenced by climate change 7 |
| Ebola | Likely bats or nonhuman primates | Bats can carry the virus without getting sick themselves 5 |
Source: Based on information from referenced studies
The emergence and spread of these diseases are fueled by various human activities. The handling of bushmeat and trade in exotic animals have been linked to outbreaks such as SARS, monkeypox, and avian influenza 1 .
Beyond infectious diseases, animals serve as crucial sentinels for environmental hazards. From the cats of Minamata to canaries in coal mines, animals often display the first signs of environmental contamination or emerging health threats 1 .
While animals have long helped us understand environmental threats, they also provide windows into fundamental biological processes. Recent groundbreaking research illustrates how animal studies continue to expand our understanding of systems that eventually translate to human health.
In September 2025, an international collaboration of scientists from the International Brain Laboratory (IBL) published a landmark achievement: the first detailed map of entire brain activity during decision-making in mice 9 . This research addresses a fundamental question in neuroscience: how do we make decisions, and which neural pathways are involved?
The study produced the first whole-brain activity map at single-neuron resolution, revealing previously unknown patterns of neural coordination during decision-making 9 .
Mice were presented with decision-making challenges that required processing sensory information and selecting appropriate behavioral responses.
Researchers utilized advanced imaging technology capable of capturing neural activity across the entire brain simultaneously.
The team recorded activity from individual neurons during the decision-making process.
Using computational approaches, researchers assembled these data points into a comprehensive brain activity map.
The resulting database was made openly available to the scientific community for further study 9 .
| Brain Region | Function in Decision-Making | Significance |
|---|---|---|
| Prefrontal Cortex | Higher-order processing and executive function | Coordinates information from multiple regions |
| Hippocampus | Memory and spatial navigation | Provides contextual information for decisions |
| Striatum | Action selection and reward processing | Influences motivation and choice selection |
| Thalamus | Sensory relay station | Filters and directs sensory information |
| Visual Cortex | Visual information processing | Processes visual cues relevant to decisions |
Source: Based on International Brain Laboratory research 9
The implications extend far beyond understanding mouse cognition. Because mouse and human brains share fundamental structural and functional similarities, these insights provide valuable clues about human neural processes. The research offers potential pathways for understanding and eventually treating human cognitive disorders such as Alzheimer's disease, schizophrenia, and traumatic brain injury that disrupt decision-making capabilities 9 .
Climate change is altering the distribution of vector-borne diseases by expanding the habitats of mosquitoes, ticks, and other disease carriers 4 . For instance, bluetongue serotype 3 has recently appeared in new parts of Europe, while other pathogens are expected to follow similar patterns as temperatures rise 4 .
The misuse of antibiotics in both humans and animals has accelerated antimicrobial resistance (AMR), a serious global health concern 4 . Success stories like Thailand reducing antimicrobial use by nearly half between 2017 and 2019, and Norway nearly eliminating antibiotics in aquaculture through effective vaccination strategies, demonstrate that progress is possible through coordinated action 4 .
Researchers are studying animal "superpowers" to advance human medicine. For example, investigations into how zebrafish regenerate tendons could revolutionize human tendon repair, while studies of tardigrade radiation resistance may lead to new protections for cancer patients undergoing radiation therapy 5 .
The Royal Veterinary College has partnered with Emulate, Inc. to develop animal species-specific Organ-Chip models. These technologies have potential applications in personalized veterinary medicine and can also inform human medical approaches, embodying the One Health concept 9 .
Increasing recognition that animal health isn't just about domestic species has brought wildlife health into the spotlight. Conservation efforts addressing issues like chronic wasting disease and white-nose syndrome in bats are essential for maintaining biodiversity and reducing zoonotic risks 4 .
The historical, new, and reemerging links between human and animal health reveal a fundamental truth: we inhabit an interconnected biological world where the health of one species cannot be separated from the health of others. From the zoonotic diseases that have shaped human history to the cutting-edge medical discoveries inspired by animal adaptations, our fates remain biologically entwined.
The One Health approach represents more than just a scientific framework—it's a necessary evolution in how we conceptualize health across species and ecosystems. As we face growing challenges like climate change, antimicrobial resistance, and pandemic threats, collaboration across human medicine, veterinary science, and environmental conservation becomes increasingly vital.
"The invisible bond between species, once a source of mystery and danger, is becoming a pathway to innovative solutions and shared resilience."
By embracing this integrated perspective, we can work toward a future where the health of people, animals, and the environment is protected through shared knowledge and collective action. In recognizing that human health is indeed connected to animal health, we take the first step toward building a healthier world for all inhabitants of our planet.
The One Health approach requires collaboration across disciplines and sectors for effective health protection.
Protecting animal and environmental health strengthens our collective resilience to health threats.