Climate change could make more than half of known human pathogens worse, scientists say

Scientists have made a distressing discovery about how global warming will affect Infectious diseases.

Climate hazards are expected to aggravate 58% of all known human pathogens, according to a study published Monday in Natural climate change. That’s more than half of the infectious diseases discovered since the end of the Roman Empire, Camilo Mora, data analyst and associate professor in the Department of Geography and Environment at the University of Hawaii Manoa, told ABC News. .

While the impact that climate change may have on human vulnerability to a range of diseases has been well accepted, the total threat that climate change poses to humanity in the context of disease was unknown, the researchers said. Previous studies have mainly focused on specific groups of pathogens, such as bacteria or viruses, response to certain hazards, such as heat waves or increased flooding, or types of transmission, such than food or water.

Mora’s team systematically reviewed the literature which revealed 3,213 empirical cases linking 286 unique human pathogenic diseases to 10 climate hazards, such as warming, flooding or drought. Of these, 277 pathogens were found to be aggravated by at least one climatic hazard, with only nine pathogens “exclusively diminished” by climatic hazards, according to the study.

PHOTO: A car washed into Squabble Creek by flooding in Buckhorn, Ky., August 5, 2022.

A car washed into Squabble Creek by flooding in Buckhorn, Ky., August 5, 2022.

Saul Young/News Sentinel via USA Today Network

58% of an authoritative list of infectious diseases documented to have impacted humanity have already been shown to be made worse by weather hazards – a finding the researchers found “shocking”, Mora said.

Examples of hazards include those that bring humans closer to pathogens, such as storms and floods, which then cause travel associated with cases of Lassa fever or Legionnaire’s disease.

Other examples are events that bring pathogens closer to humans, in which warming increases in areas over which organisms that transmit diseases, such as Lyme disease, dengue, and malaria, are active.

PHOTO: A sunflower grows in a field during the drought, July 31, 2022.

A sunflower grows in a field during drought, July 31, 2022.

Pablo Blazquez Dominguez/Getty Images

There is a wide taxonomic diversity of human pathogenic diseases, such as bacteria, viruses, animals, plants, fungi and protozoa, as well as the types of transmission — for example, vector-borne, airborne, direct contact — which can be affected by warming, heat waves, droughts, wildfires, extreme rainfall, flooding and sea level rise, according to the study.

Changes in the geographic distribution of species are one of the most common ecological indications of climate change, according to the study. Warming and changes in precipitation, for example, have been associated with the expansion of the range of vectors such as mosquitoes, ticks, fleas, birds and several mammals, which have subsequently been implicated in epidemics by viruses, bacteria, animals and protozoa including dengue fever, chikungunya, plague, Lyme disease, West Nile virus, Zika, trypanosomiasis, echinococcosis and malaria.

The researchers found 1,006 unique pathways in which climatic hazards, via different types of transmission, led to cases of pathogenic diseases.

Warming at higher latitudes has allowed vectors and pathogens to survive the winter, worsening outbreaks of several viruses, such as an outbreak of anthrax in the Arctic Circle that may have come from an ancient bacterial strain that has emerged from an unearthed animal corpse as the frozen ground thawed, according to the study.

COVID-19 is an example of how a single disease can create a thematic shift in society, Mora said, adding that he didn’t believe in the most recent pandemic – and the animal-to-human transmission which probably caused it – could have happened had it not been for global warming.

PHOTO: An aerial view of ice pancakes and melting in the Arctic, July 19, 2022.

An aerial view of pancake ice and melting in the Arctic, July 19, 2022.

Kerem Yucel/AFP via Getty Images, FILE

This research reveals more evidence that humans will have difficulty adapting to climate change, especially those in developing countries, Mora said.

“The magnitude of vulnerability when you think of one or two diseases – okay, of course we can deal with that,” he said. “But when you’re talking about 58% of diseases, and 58% of those diseases can be affected or triggered in 1,000 different ways. So for me, that was also indicative of the fact that we’re not going to be able to s adapt to climate change.

Extreme weather events such as Drought and fires to the west, flooding both interior and coastal areas and extreme heat in places that did not previously experience such high temperatures is becoming more common, Mora said.

The results reveal unique pathways through which climate hazards can lead to disease, highlighting society’s limited adaptive capacity and highlighting the need to reduce greenhouse gas emissions, the authors said.

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