Biodiversity loss is the biggest environmental driver of infectious disease outbreaks, making them more dangerous and widespread, a study has found.
New infectious diseases are on the rise and they often originate in wildlife. In meta-analysis published in the journal Nature, researchers found that of all the “drivers of global change” destroying ecosystems, the loss of species was the most likely to increase the risk of outbreaks. Biodiversity loss has been followed by climate change and the introduction of non-native species.
“The take-home messages are that biodiversity loss, climate change and introduced species increase disease, while urbanization reduces it,” said lead researcher Prof Jason Rohr from the University of Notre Dame in the US. Experts analyzed nearly 1,000 studies of global environmental drivers of infectious diseases, covering all continents except Antarctica. They looked at both the severity and incidence of disease in plant, animal and human hosts.
The team focused on five global change drivers – loss of biodiversity, climate change, chemical pollution, non-native species and habitat loss. They found that four out of five increased disease spread: all but habitat loss increased disease. Their results were the same for human and non-human diseases.
Habitat change has reduced the risk due to the trend of people moving to a specific type of habitat – cities. Urban areas tend to have less disease, partly because of better public sanitation, but also because there is less wildlife. Rohr said: “In urban areas with a lot of concrete, there are a much smaller number of species that can thrive in that environment. From a human disease perspective, there is often greater sanitation and health infrastructure than in rural settings.”
Interest in zoonotic diseases has increased since the Covid pandemic, which some researchers believe came from a bat. Many other diseases that currently alarm global health authorities – including swine flu and bird flu – also originated in wildlife. Three-quarters of emerging diseases in humans are zoonotic, meaning they also infect wild and domestic animals.
Previous studies have pointed to links between these diseases and environmental change (for example, global warming may mean malaria becomes more widespread), but it was previously unclear which environmental drivers had the biggest impact. The researchers noted that many of the drivers are interconnected: “For example, climate change and chemical pollution can cause habitat loss and alteration, which in turn can cause biodiversity loss.”
Researchers say that reducing emissions, reducing biodiversity loss and preventing invasive species can all help reduce the burden of disease. “We hope that our analyzes will facilitate disease control, mitigation and surveillance efforts worldwide,” researchers wrote in the paper.
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