An analysis of over 58,000 outbreaks of 32 diseases in 169 countries found that the fragmentation of ecosystems and climate change-related declines in rainfall drove up the risk of diseases that spread from animals, mosquitoes, ticks, and fleas to people. CIDRAP has the news.

The study was published in Nature. An international group of researchers assessed zoonotic disease outbreaks like coronaviruses, Ebola, and mpox and vector-borne diseases, like dengue, Lyme disease, and malaria. They then systematically tested how 16 hypothesized social and environmental factors influence where outbreaks occur.

Outbreak risk was generally higher in areas where people and livestock live close to fragmented and forested ecosystems. Those people are more likely to encounter animals that thrive in those environments and can carry diseases more easily. Vector-borne diseases from dengue and Zika virus saw especially increased risks in areas with fragmented ecosystems and declining rainfall.

The effects of factors such as deforestation, climate warming, and agricultural intensification varied widely by disease. These findings challenge the assumption that a common set of environmental factors is driving the rising risk of emerging infectious diseases.

Healthcare access plays a critical role in determining where outbreaks are reported. The probability of reporting an emerging disease outbreak fell by 32% on average for every additional hour of travel to the nearest healthcare facility. 

The researchers urge taking a more proactive and holistic approach to preventing epidemics and pandemics, strengthening health systems, and global coordination of disease surveillance and ecosystem-based interventions for important diseases.