A Sick Climate: How Climate Change Fuels the Spread of Cholera and Similar Diseases
Written by Mara Murphy
Edited by Sam Levya
April 5, 2024
Edited by Sam Levya
April 5, 2024
Public Health
Climate change, the long-term alteration of temperature and weather patterns, is one of the most pressing challenges humanity faces today. From rising sea levels, which threaten coastal communities and infrastructure, to an uptick in the number and frequency of extreme weather events, including hurricanes, heatwaves, droughts, wildfires, and floods, no area of Earth is spared. This is especially true when considering an often overlooked consequence of climate change–the dangerously increasing prevalence of infectious diseases.
Because of climate change, once-localized diseases are becoming increasingly widespread, and seasonal variations are changing. This shift has the potential to overwhelm healthcare systems and public health responses, especially in still-developing countries. One such disease is cholera, which kills an estimated 143,000 people annually (Centers for Disease Control and Prevention).
Cholera is notorious for its sudden and severe onset of symptoms, often characterized by profuse diarrhea and vomiting. This rapid loss of fluids can lead to dehydration and electrolyte imbalances, which, if left untreated, can be fatal. The bacterium Vibrio cholerae, a comma-shaped microorganism, causes the disease. Vibrio cholerae thrives in aquatic environments, especially in warm, brackish water, where it forms a reservoir for infection (Science).
Cholera is intimately tied to climate patterns because changes in temperature, precipitation, and humidity affect its transmission. As global temperatures rise, so do the temperatures of many coastal and inland water bodies. This increase in water temperature creates a more favorable environment for the proliferation of Vibrio cholerae, increasing the risk of contamination in water sources and ultimately enhancing the likelihood of cholera outbreaks.
But climate change does not just involve warming temperatures; it also involves shifts in precipitation patterns. Increased rainfall, particularly in regions susceptible to flooding, can lead to the contamination of water sources with waste, where Vibrio cholerae may be present (Science). Flooding events can disrupt sanitation systems and sewage infrastructure, allowing for the rapid spread of the bacterium and increasing the likelihood of cholera outbreaks. Heavy rainfall can also lead to the proliferation of waterborne diseases, making cholera a permanent threat in flood-prone areas.
Another major link between infectious diseases and climate change lies in the alterations to the distribution and behavior of disease vectors. Vectors are organisms, like mosquitoes and ticks, that can transmit diseases to humans. They are highly sensitive to environmental conditions, and changes in temperature and precipitation patterns directly impact their distribution, behavior, and reproduction (University Corporation for Atmospheric Research). Warmer temperatures and altered rainfall patterns often expand the geographic range of disease vectors, allowing them to thrive in areas previously unsuitable for their survival. For instance, the Aedes aegypti mosquito, responsible for transmitting diseases such as Zika, yellow fever, and chikungunya, is now found in regions that were once too cold for its survival due to rising temperatures (BioMed Central).
The link between climate change and infectious diseases has serious implications for public health, as increased disease transmission strains healthcare systems and leads to higher healthcare costs. The burden of disease falls disproportionately on low-income communities and regions with limited access to healthcare, exacerbating health disparities.
As our planet continues to undergo rapid changes, we must recognize that outbreaks of infectious diseases such as cholera are not isolated events, but are tied to environmental shifts. Failure to address the root causes of climate change will increase disease burdens, exacerbate global health inequalities, and threaten human well-being.
References:
Cholera - Vibrio Cholerae Information. Centers for Disease Control and Prevention. (2023, August 7). https://www.cdc.gov/cholera/general/index.html.
Climate Change and Vector-Borne Disease. University Corporation for Atmospheric Research Center for Science Education. https://scied.ucar.edu/learning-zone/climate-change-impacts/vector-borne-disease
Colwell, R. R. (1996, December 20). Global Climate and Infectious Disease: The Cholera Paradigm. Science. https://www.science.org/doi/full/10.1126/science.274.5295.2025
Piovezan-Borges, A. C., Valente-Neto, F., Urbieta, G. L., Laurence, S. G. W., & Roque, F. de O. (2022, September 29). Global Trends in Research on the Effects of Climate Change on Aedes Aegypti: International Collaboration has Increased, but Some Critical Countries Lag Behind - Parasites & Vectors. BioMed Central. https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-022-05473-7