Waterborne disease

Waterborne diseases happen when people come into contact with polluted water. These illnesses are caused by tiny living things called pathogens. These pathogens include bacteria, viruses, and protozoa. Some are even larger, like parasitic worms. For example, roundworms can cause a disease known as guinea worm disease. Other parasites, like blood flukes, belong to a group called Schistosomatidae. It is not just germs that make water unsafe, though. Chemical pollutants like benzene or toluene can also enter water lines. These chemicals might leak from pipes or industrial dumping.

These diseases move from water to people in a few ways. The main way is through ingestion, which means swallowing the water. You can also get sick by bathing or washing in it. Even eating food that touched dirty water can cause illness. Some germs use a path called the fecal-oral route to spread. This happens when waste gets into the water supply. Once inside, many parasites invade the digestive tract. They can even enter the circulatory system to move through the body. Common symptoms include vomiting, diarrhea, nausea, and stomach cramps.

History shows that we have learned much about controlling these germs. Scientists used microbiology to understand how tiny pathogens work. We also learned how to use filtration to clean water. Chlorination is a method that uses chemicals to kill germs. Better sanitation systems help keep waste away from our drinking water. Some new tools, like solar-powered desalination, help make water safe. Even replacing old plastic pipes with metal can help. This is very important in areas prone to wildfires.

Today, many people still face great risks from dirty water. About 2.1 billion people lack access to safe drinking water. This is one out of every four people on Earth. In some places, like the Middle East or Sub-Saharan Africa, it is hard to get clean water. War can make this even worse by destroying pipes and hospitals. In Yemen, there were 2.5 million cases of cholera between 2016 and 2022. In Gaza, water systems have been harmed by war. In 2024, there were 600,000 cases of acute diarrhea there. An infant even had polio in that region.

We can see how these issues connect to our changing world. Climate change affects the temperature and quality of our water. Warmer water can help bacteria like Vibrio cholerae grow faster. Heavy rain and flooding can also spread germs by overwhelming water systems. Floods can cause dirty water to flow back into clean sources. This is a big challenge for many growing cities. We can use technology to help, like the H2O Maghreb program. This program uses virtual reality to teach people about clean water. It helps people in Morocco learn how to treat water safely.