More than half of the hundreds of infectious diseases known to humans, including malaria, hantavirus, cholera, and anthrax, have been aggravated by climate-related hazards like flooding, heat waves, and drought, according to a recently published study.
Researchers looked through the medical literature of established cases of illnesses and found that 218 out of the known 375 human infectious diseases, or 58%, seemed to be made more severe by one of 10 types of extreme weather connected to climate change, according to a study in Monday’s journal Nature Climate Change. In the study, 1,006 pathways were mapped from climate hazards to sick people. Disease-carrying mosquitoes, rats, and deer may infect people during downpours and flooding.
A warming ocean and heat waves contaminate seafood and other foods we eat, while droughts result in bats carrying viral infections. The influence of climate on human health has been known since Hippocrates, but this study shows just how widespread it is.
“If climate is changing, the risk of these diseases is changing,” said study co-author Dr. Jonathan Patz, director of the Global Health Institute at the University of Wisconsin-Madison. It is critical to think of diseases as symptoms of a sick Earth, according to doctors like Patz.
“The findings of this study are terrifying and illustrate well the enormous consequences of climate change on human pathogens,” said Dr. Carlos del Rio, an Emory University infectious disease specialist, who was not part of the study. “Those of us in infectious diseases and microbiology need to make climate change one of our priorities, and we need to all work together to prevent what will be without doubt a catastrophe as a result of climate change.”
In addition to looking at infectious diseases, the researchers expanded their search to look at all types of human illnesses, including non-infectious illnesses such as asthma, allergies, and even animal bites, to see how many illnesses, including infectious diseases, could be linked to climate hazards. The study found 286 unique sicknesses, 223 of which were worsened by climate hazards, nine were diminished by climate hazards, and 54 had both aggravated and diminished symptoms.