Climate Postcards: Climate Change Makes Me Sick!

Climate Postcards: Water-Borne Illness

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Below, you will find detailed information, resources, and opportunities to take climate-protective action.

What’s the relationship between climate change and water-borne illnesses?

As climate change continues, water-borne illnesses are likely to become more common. That’s because climate change increases precipitation, storm surges, and sea temperatures. These environmental factors contribute to flooding and runoff that can spread sewage, chemicals and disease agents. They also favor the growth, survival and spread of bacteria, viruses and toxins created by harmful algae. As a result, more people will likely be exposed to water-borne illnesses through ingestion, inhalation and skin contact, as well as consumption of contaminated fish and shellfish.

Heavy Rainfall and Flooding can Affect Drinking Water

Climate change increases the frequency and intensity of heavy rainfall. This leads to runoff and to flooding, especially in river and coastal areas. Drinking water can be contaminated by chemicals, gasoline, coal ash, sewage and more.

  • Extreme precipitation events have been linked to increased levels of pathogens in treated drinking water, and cases of gastrointestinal illness in children.
    • In 1993, Milwaukee experienced its heaviest rainfall in over 50 years. This led to a Cryptosporidium outbreak that accounted for 403,000 illnesses and over 50 deaths. Cryptosporidium is a parasite that infects the intestines of people and animals.
  • Groundwater wells receive limited water treatment. This makes them more susceptible to water contamination from extreme precipitation events and increases the risk of waterborne illnesses in those who consume it.
    • In 2000, a heavy rainfall event in Walkerton, Ontario, Canada, carried agricultural runoff containing E.coli into the town’s primary water source, a shallow well. This extreme weather-related event caused 2,300 illnesses and seven deaths.

Recreational Exposure

As climate change continues, the intersection of flooding and higher temperatures is likely to transport pathogens into recreational waters and foster their growth.

  • Naegleria fowleri (commonly referred to as the “brain-eating amoeba“) is found in warm freshwater like lakes and ponds. The amoeba enters the nose and travels to the brain, causing primary amebic meningoencephalitis (PAM), a potentially fatal disease.
  • PAM begins with a severe frontal headache, fever, nausea, and vomiting and progresses to include seizures, hallucinations, coma and, frequently, death.
  • Changes in the Great Lakes’ rainfall, higher lake temperatures, and low lake levels have been linked to increases in fecal bacteria levels in those waters.
  • Levels of Salmonella and Campylobacter have been found to increase in freshwater streams in the southeastern U.S. during summer months following heavy rainfall. People infected with Salmonella suffer from diarrhea, fever, and abdominal cramps. Campylobacter causes diarrhea, cramping, abdominal pain, and fever.
  • Legionella, which causes Legionnaires’ Disease, a respiratory illness, grows best in warm freshwater and is usually absorbed by inhaling droplets. Legionnaires’ disease causes cough, shortness of breath, high fever, muscle aches, and headaches.

Fish and Shellfish Contamination

Water contamination from sewage overflows can affect seafood.

  • Fish and shellfish can accumulate viruses found in sewage and put consumers at risk for gastrointestinal viruses such as norovirus and hepatitis A.
  • Norovirus results in stomach pain, nausea, diarrhea, and vomiting. Symptoms vary for different age groups, but children and the elderly are most severely impacted.
  • Hepatitis A can cause debilitating symptoms like diarrhea. It can also cause acute liver failure, which is associated with high mortality.

As climate change has raised sea surface temperatures and altered precipitation patterns, harmful algal blooms have become more common and expanded their geographical range. These blooms are dangerous because they produce potent toxins which can contaminate seafood.

  • Ciguatera fish poisoning (CFP) is influenced by climate and is frequently reported in humans. CFP results in nausea, vomiting, diarrhea, abdominal pain, pain or the sense of loose teeth, itching, blurred vision or even transient blindness and neurological symptoms.
  • Paralytic Shellfish Poisoning is the most common and more severe form of shellfish poisoning. Symptoms include numbness, tingling sensation on the body, headache, nausea, vomiting, and diarrhea. A large dose of the toxin may lead to the inability to control bodily movements, difficulty swallowing, mental status change, flaccid paralysis (feeling weak or paralyzed), and respiratory failure.

How can I help fight climate change?

  • Use our postcards to query your federal, state or local government representatives: What are they doing to protect your community from the dangers to health posed by climate change?
    • Climate change is accelerated by burning fossil fuels. In order to slow climate change and protect air quality, we must replace fossil fuels with renewable energy and energy efficiency
  • Join PSR’s Activist List
  • Spread the knowledge by sharing our postcards!


All Climate Postcards

Climate Postcards: Water-Borne Illness

Climate Postcards: Vector-Borne Disease

Climate Postcards: Insect-Borne Disease

Climate Postcards: Heat

Climate Postcards: Extreme Weather

Climate Postcards: Allergies

Climate Postcards: Air Quality

Climate Postcards: Agriculture