Infectious diseases are getting worse due to climate change

More than 58% of human diseases caused by pathogens, such as dengue fever, hepatitis, pneumonia, malaria and Zika, have been exacerbated by climate change, according to a study published August 8 in Nature Climate Change .

The findings come at a time when many parts of the world are experiencing unprecedented droughts and heat waves, and the world is still grappling with the devastating 2020-2021 COVID-19 pandemic.

Given the widespread and widespread consequences of the COVID-19 pandemic, it is truly frightening to discover the enormous health vulnerability resulting from greenhouse gas emissions.said Camilo Mora, lead author of the study and a professor in the Department of Geography and Environment at the University of Hawaii.


Research on diseases and climate change

Researchers at this Manoa-based study house have systematically searched published research for proven cases of infectious diseases affected by climate change-related events, such as warming, floods, droughts, storms, changes in natural land cover and ocean climate change.

They calculated the impact of disease by bringing together three previously unrelated factors: what kind of agent made people sick, for example, was it a bacterium or a virus; how they contracted the disease (via vectors, food or water); and any climate change events that may have had an impact, such as rains, droughts or global warming.

The team reviewed more than 70,000 papers and found that 218 of 375 infectious diseases had been exacerbated by climate change.

The conclusions of the study on diseases and climate change

We knew in advance that there was a link between climate change and diseases caused by pathogens, but our motivation was to quantify this effect, to determine its magnitudeMora pointed out.

It was almost a shock to see how the database we built with these connections grew; it is scary to know that 58% of diseases can be affected by climate change“, he underlined.

They found that rising temperatures increased the area of ​​activity of pathogenic organisms, usually those transmitted by insects, such as dengue fever, chikungunya, Lyme disease, West Nile virus, trypanosomiasis, echinococcosis and malaria.

They also found that certain climatic events such as floods, sea level rise and storms bring pathogens closer to humans, causing leptospirosis, Lassa fever, giardiasis, gastroenteritis, among others. cholera, pneumonia and hepatitis.

A “Pandora’s box”

Genetic analysis of an Arctic anthrax outbreak suggests the bacterial strain may have emerged from an unearthed animal carcass as the frozen ground melted, and researchers fear thawing permafrost could open a “box of Pandora” of ancient illnesses.

They also discovered that viruses can become stronger after exposure to heat waves because they reduce the effectiveness of the body’s defense mechanism: fever.

Silvana Goenaga, professor of ecology and zoonosis at the Universidad Nacional del Noroeste in the province of Buenos Aires, who was not involved in the study, said that “A notable aspect of this research is to highlight that climatic events generate an increase in the contact of various pathogens with human populations.”.

The authors point out that the increase in global temperatures generates a geographical expansion of arthropods such as mosquitoes and ticks, which act as vectors (disease transmitters) of viral agents, bacteria and parasites (dengue fever, rickettsiosis, malaria) . In turn, these increases also accelerate the reproductive cycles of arthropods and the replication cycles of viral agents transmitted by them.remarked Goenaga.

It is imperative to intensify vector control programs and surveillance of public health systems. It is necessary to know the new distribution of vectors and to be attentive to new pathologies which could appear“, he ordered.

Mora, for his part, pointed out: “Our research has shown that these are not speculations but real numbers. To solve this problem, we must reduce global greenhouse gas emissions, which requires aggressive and urgent action.”.

See the link to the study in Nature Climate Change

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