Biodiversity Loss Emerges as Leading Driver of Infectious Disease Outbreaks

A meta-analysis study has revealed that biodiversity loss is the leading environmental factor driving the emergence and spread of infectious diseases, making them more severe and widespread. The research highlights that new infectious diseases are increasingly originating from wildlife. Published in the journal Nature, the meta-analysis indicates that among all the "global change drivers" impacting ecosystems, species loss poses the greatest threat by escalating the risk of disease outbreaks. Following biodiversity loss, climate change and the introduction of invasive species were also significant contributors.

Lead researcher Professor Jason Rohr from the University of Notre Dame noted that while biodiversity loss, climate change, and invasive species exacerbate disease risks, urbanization tends to reduce them. The research team conducted an extensive review of nearly 1,000 studies addressing the global environmental factors influencing infectious diseases across all continents except Antarctica. They assessed the severity and prevalence of diseases in plants, animals, and humans.

The study focused on five key global change drivers: biodiversity loss, climate change, chemical pollution, non-native species, and habitat loss. The analysis showed that four out of these five drivers—excluding habitat loss—contributed to the increased spread of diseases. This pattern held true for both human and non-human diseases.

Interestingly, habitat change was associated with a reduced risk of disease, largely due to the trend of human migration toward urban areas. Cities tend to have lower disease rates, partly due to improved public sanitation and reduced wildlife presence. Rohr explained that urban environments, dominated by concrete, support fewer species capable of thriving there. Additionally, urban areas often benefit from better sanitation and healthcare infrastructure compared to rural settings.

The COVID-19 pandemic, which some experts believe originated from bats, has heightened interest in zoonotic diseases—those that can be transmitted between animals and humans. Other diseases currently concerning global health authorities, such as swine flu and avian flu, also have origins in wildlife. Notably, three-quarters of emerging human diseases are zoonotic.

While previous research had identified links between environmental changes and the spread of such diseases (for example, global warming potentially increasing the reach of malaria), it was unclear which environmental factors had the most significant impact. The researchers also pointed out the interconnectedness of these drivers, noting that climate change and chemical pollution can lead to habitat loss and biodiversity decline, further exacerbating disease risks.

The study suggests that efforts to curb emissions, protect biodiversity, and prevent the spread of invasive species could help mitigate the global burden of infectious diseases. The researchers expressed hope that their findings would inform and enhance global disease control, mitigation, and surveillance strategies.