Why Cats, Dogs, and Even Whales Are Getting Human Diseases

Look to human causes

By Society for Risk Analysis

Across the globe, animals from household pets to marine wildlife are developing chronic diseases once thought to primarily affect humans. 

Dogs, cats, dairy cows, and sea turtles are showing increasing rates of cancer, obesity, diabetes, and joint degeneration. 

Understanding what drives this rise in non-communicable diseases (NCDs) is essential not only for protecting animal health but also for improving human well-being.

Despite the growing urgency, comprehensive and interdisciplinary research on animal NCDs remains limited.

A New Model for Tracking Animal Health Risks

A study published today (November 11) in Risk Analysis introduces a fresh conceptual framework aimed at improving how scientists monitor and manage chronic disease in animals. The research, led by animal scientist Antonia Mataragka at the Agricultural University of Athens, outlines an evidence-based risk assessment model. This framework also has implications for public health, as both humans and animals are facing a similar surge in chronic conditions.

Genetic and Environmental Factors Behind Disease

Drawing on published data from multiple studies on animal NCDs, Mataragka’s analysis identifies a range of biological and environmental drivers. Genetic predisposition plays a key role: certain animal populations face higher risks because of selective breeding. For example, purebred cats and dogs bred for physical traits and livestock bred for high productivity often suffer elevated rates of diabetes and mitral valve disease.

Environmental pressures further worsen disease risk. Poor diets, lack of exercise, and long-term stress are now recognized as shared contributors to illness across species.

Examples of a Growing Epidemic

The research highlights examples that illustrate how widespread these issues have become. Obesity affects more than half of domestic cats and dogs, fueling a steady rise in feline diabetes. Farm animals are similarly affected: around 20% of intensively raised pigs develop osteoarthritis. In aquatic environments, beluga whales show gastrointestinal cancers, and farmed Atlantic salmon suffer from cardiomyopathy syndrome. Wildlife exposed to industrial pollution in estuaries contaminated with polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) show liver tumor rates between 15% and 25%.

Human-Driven Change and a Planet Under Stress

Mataragka’s work points to ecological disruption as a major force behind the spread of disease. Human activities such as urbanization, deforestation, and climate change intensify exposure to harmful conditions. Warming seas and coral degradation have been linked to higher tumor rates in fish and marine turtles. At the same time, heat stress and urban pollution are contributing to obesity, diabetes, and immune disorders in pets, birds, and other mammals.

“As environmental changes accelerate disease emergence, the absence of early diagnostic systems further delays the detection of NCDs in animals,” says Mataragka. “While organizations like the World Health Organization provide extensive data on NCD mortality in humans, similar detailed statistics for animals are scarce. This indicates the need for more comprehensive research and enhanced surveillance in veterinary health to better understand and address these issues.”

Linking Health Across Species and Ecosystems

The study measures NCD prevalence in various species and explores how risk factors contribute to disease development. It also recommends prevention and intervention strategies at four interconnected levels: individual, population (herd), ecosystem, and policy. The findings show that pollution, habitat loss, dietary imbalance, and climate stress are major drivers increasing animals’ susceptibility to chronic illness.

Integrating Human, Animal, and Environmental Health

Mataragka’s proposed framework combines two complementary approaches: One Health and Ecohealth. Both emphasize the connection between human, animal, and environmental well-being (but often operate separately). By merging them, her model demonstrates how genetic vulnerability interacts with ecological and social factors to produce disease across species.

She hopes this interdisciplinary model will encourage more unified health monitoring that includes humans, animals, and the environments they share. Such collaboration could help identify early warning signs of disease and reduce chronic illness across all forms of life on Earth.

Reference: 11 November 2025, Risk Analysis.