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Waterborne disease

life science Maturity 11-13 Next article →

Waterborne diseases are illnesses caused by pathogenic micro-organisms in contaminated water. Pathogens are tiny living things that can cause disease. These include bacteria, viruses, protozoa, and metazoan parasites. Many of these organisms act as intestinal parasites. They invade the tissues or the circulatory system through the walls of the digestive tract. Waterborne disease refers specifically to infections transmitted through contact with or consumption of microbially polluted water. This is different from water-related diseases, which include any health effects caused by changes in water quantity or quality.

Hepatitis A virus 01
Hepatitis A virus 01

The transmission of these diseases occurs through several specific pathways. The primary mode is ingestion, which means swallowing contaminated water. People can also be exposed through bathing, washing, or eating food that was exposed to dirty water. Many pathogens follow the fecal-oral route. This is a pathway where waste enters the water supply and then reaches a person's mouth. Some organisms, like certain protozoa, can also enter through the eyes. For example, Acanthamoeba keratitis occurs when people clean contact lenses with contaminated water. This can cause eye redness, blurred vision, and extreme sensitivity to light.

Pathogens are categorized into different biological classes. Protozoa are single-celled organisms that cause various illnesses. Giardia lamblia is the most common intestinal parasite and is often found in untreated water. Cryptosporidium parvum can collect on water filters that cannot be disinfected. Metazoan parasites are larger, multi-cellular organisms. These include Nematoda, which are commonly known as roundworms. Roundworms can cause diseases like Dracunculiasis, also called guinea worm disease. Another group is the Schistosomatidae, which are a family of blood flukes.

Red blood cells infected with malaria
Red blood cells infected with malaria

Beyond biological pathogens, chemical pollutants also contaminate water supplies. Volatile organic compounds, or VOCs, are a major concern. These include chemicals like benzene, toluene, ethylbenzene, and xylenes. These substances can enter water lines through industrial dumping or pipeline leaks. They can also come from jet fuel spills or heat-damaged plastic pipes. Exposure to VOC-contaminated water is linked to serious health issues. These include headaches, nausea, and the formation of tumors. It can also increase the risk of cancer, including leukemia.

History shows that scientific advances have helped control these diseases. Improvements in microbiology allowed scientists to understand how pathogens function. The development of filtration and chlorination provided ways to clean water. Sanitation systems were improved to keep waste away from drinking sources. Modern sustainable technologies, such as solar-powered desalination, are also used today. In some wildfire-prone areas, replacing damaged plastic piping with metal alternatives reduces contamination risks. Programs like H2O Maghreb use virtual reality simulations to educate people in Morocco about water treatment.

Global statistics show that waterborne disease remains a massive challenge. Approximately 2.1 billion people, or 1 in 4 people globally, lack access to safe drinking water. This lack of access is especially prevalent in developing countries. Socioeconomic factors like poverty and lack of education increase the risk. In Yemen, there were 2.5 million cases of cholera between 2016 and 2022. War and political turmoil also destroy the infrastructure needed for clean water. In Gaza, water consumption is about 80 liters per person per day, compared to 300 liters in America. In 2024, Gaza saw 600,000 cases of acute diarrhea due to damaged water systems.

Climate change is creating new risks for waterborne illness. Changes in the environment influence the growth and survival of bacteria. Warmer water temperatures can increase the yield of bacteria in drinking water systems. It also promotes the growth of Vibrio cholerae, which causes cholera. Climate change also leads to more frequent droughts and flooding. Heavy rainfall and flooding can overwhelm sanitation systems. This causes backflow, which contaminates groundwater and other drinking sources. These environmental changes disproportionately affect vulnerable populations in informal settlements.

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File:Red blood cells infected with malaria.jpg
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File:Hepatitis A virus 01.jpg
Hepatitis A virus 01.jpg
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