Study: Climate hazards aggravate more than half of human diseases caused by pathogens

According to an article recently published in Natural climate change. The comprehensive assessment revealed empirical evidence on climate risks aggravating pathogens including dengue fever, hepatitis, pneumonia, malaria and zika.

Researchers at the University of Hawaii at Mānoa performed a comprehensive systemic search of empirical examples of the impacts of 10 climate hazards sensitive to greenhouse gas (GHG) emissions on every known human pathogenic disease, combining 2 lists making authority of all known pathogenic infections and diseases that have affected mankind in recorded history. Hazards included warming, drought, heat waves, wildfires, extreme rainfall, floods, storms, sea level rise, ocean biogeochemical changes, and land cover changes.

They reviewed more than 70,000 scientific papers to find empirical examples of every possible combination of climate hazards impacting each known disease. Their findings revealed that warming, precipitation, flooding, drought, storms, land cover change, ocean climate change, fires, heat waves and sea level changes all influence diseases triggered by viruses, bacteria, animals, fungi, protozoa, plants and chromists.

Pathogenic diseases were mainly transmitted by vectors; however, case examples were also found for waterborne, airborne, direct contact, and foodborne transmission routes. The research found that 218 of 375 (58%) known human pathogenic diseases were affected by at least 1 climate hazard at some point in time, via 1006 unique pathways.

“Given the widespread and widespread consequences of the COVID 19 pandemic, it was truly frightening to discover the massive health vulnerability resulting from greenhouse gas emissions,” said Camilo Mora, BSc, PhD, professor of geography at the College of the social sciences, in a press release. “There are simply too many diseases and transmission routes for us to think we can really adapt to climate change. This highlights the urgent need to reduce greenhouse gas emissions globally.

They also found that weather hazards bring people closer to pathogens, as weather hazards are implicated in the forced displacement and migration of people causing or increasing new contact with pathogens. Storms, floods and sea level rise have caused human displacement implicated in cases of leptospirosis, cryptosporidiosis, Lassa fever, giardiasis, gastroenteritis, legionellosis, cholera, salmonellosis , shigellosis, pneumonia, typhoid, hepatitis, respiratory diseases and skin diseases, among others .

Weather vagaries were also found to have enhanced specific aspects of pathogens. Improvements included improved climatic suitability for reproduction, accelerated life cycle, increased seasons/likely duration of exposure, improved pathogen vector interactions, and increased virulence.

In some cases, the vagaries of the weather have also played a role in the growing ability of pathogens to cause more severe disease. Heat waves have been suggested as a natural selective pressure towards “heat-tolerant” viruses.

In addition, the human ability to cope with pathogens has been reduced by climatic hazards, which alter body condition, increase stress from exposure to hazardous conditions, force people to live in hazardous conditions and damage infrastructure, forcing exposure to pathogens and/or reducing access to medical care. .

“We knew that climate change could affect human pathogenic diseases,” said co-author Kira Webster, a doctoral student in geography at the College of Social Sciences, in a press release. “Yet, as our database has grown, we have become both fascinated and distressed by the overwhelming number of case studies available that already show how vulnerable we are becoming to our growing greenhouse gas emissions. greenhouse effect.”

Although the majority of diseases were aggravated by climatic hazards, the researchers noted that 63 of the 286 diseases were in fact mitigated by climatic hazards. For example, warming appears to have reduced the spread of viral diseases likely linked to conditions unsuitable for the virus or a stronger immune system in warmer conditions.

However, most diseases that were mitigated by at least 1 hazard were sometimes aggravated by another and sometimes even the same hazard. The researchers created an interactive web page to demonstrate the link between climate hazards and a case of disease, allowing users to query specific hazards, pathways and groups of diseases.


The impact of climate change on human pathogenic diseases is the subject of a new study by UH researchers. Eurek alert. Press release. August 8, 2022. Accessed August 19, 2022.

Study: Climate hazards aggravate more than half of human diseases caused by pathogens

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