Water is essential for life. It is involved in many biological processes such as digestion, circulation, excretion, and temperature regulation. It is also used for many human activities such as agriculture, industry, hygiene, and recreation. However, water can also be a source of disease and death. Waterborne diseases are infections that can be transmitted through contaminated water. They are caused by microorganisms such as bacteria, viruses, protozoa, or helminths that can infect the gastrointestinal tract, the respiratory tract, the skin, or other organs. Some of the most common waterborne diseases are cholera, typhoid fever, dysentery, hepatitis A, giardiasis, and schistosomiasis.
In this article, you will learn more about the history, transmission, prevention, and treatment of waterborne diseases. You will also learn about the importance of potability (the quality of water that is safe for human consumption) and how to ensure it.
A Brief History of Waterborne Diseases
The history of waterborne diseases is intertwined with the history of human civilization. Since ancient times, people have been exposed to various pathogens that can cause waterborne diseases. Some of the earliest recorded outbreaks of waterborne diseases include the plague of Athens in 430 BC, the Antonine plague in 165 AD, and the Black Death in 1347-1351. These pandemics killed millions of people and changed the course of history.
However, it was not until the 19th and 20th centuries that significant advances were made in the fields of microbiology, epidemiology, and public health to understand and combat waterborne diseases. In 1854, John Snow discovered the source of a cholera outbreak in London by mapping the cases and identifying a contaminated water pump. In 1880, Robert Koch isolated the bacterium that causes cholera and established the criteria to prove the causative agent of a disease. In 1892, Dmitri Ivanovsky discovered the first virus, which causes tobacco mosaic disease. In 1908, Jersey City became the first city in the US to disinfect its water supply with chlorine.
Since then, many more discoveries and innovations have been made to prevent and treat waterborne diseases. Water treatment methods such as filtration, coagulation, sedimentation, disinfection, and reverse osmosis have been developed to remove or destroy pathogens from water sources. Water quality standards and regulations have been established to monitor and control the safety and quality of drinking water. Water distribution systems and sanitation facilities have been improved to provide access to clean and safe water for domestic and industrial use. Water education campaigns and behavior change interventions have been implemented to raise awareness and improve practices among individuals and communities.
How Waterborne Diseases Are Transmitted
Waterborne diseases are transmitted when an infected person or animal sheds pathogens into a water source or a water system. The pathogens can then contaminate other water sources or systems through runoff, leakage, overflow, or cross-connection. The pathogens can also survive or multiply in water sources or systems due to inadequate treatment or maintenance. The contaminated water can then infect other people or animals who consume it or come into contact with it.
There are two main modes of transmission for waterborne diseases: fecal-oral transmission and skin penetration transmission. Fecal-oral transmission occurs when pathogens from feces (human or animal waste) enter the mouth through contaminated water or food. This mode of transmission is common for bacterial infections such as cholera, typhoid fever, dysentery, or E. coli; viral infections such as hepatitis A or norovirus; protozoan infections such as giardiasis or cryptosporidiosis; or helminthic infections such as ascariasis or hookworm.
Skin penetration transmission occurs when pathogens from water penetrate the skin through wounds or pores. This mode of transmission is common for bacterial infections such as leptospirosis or necrotizing fasciitis; viral infections such as dengue fever or chikungunya; protozoan infections such as leishmaniasis or trypanosomiasis; or helminthic infections such as schistosomiasis or dracunculiasis.
How to Prevent and Treat Waterborne Diseases
The prevention and treatment of waterborne diseases depend on several factors such as the type and severity of the infection, the availability and effectiveness of interventions, the resources and capacities of the health system, and the cooperation and compliance of the population.
There are three main levels of prevention and treatment for waterborne diseases: primary prevention (avoiding exposure to contaminated water), secondary prevention (interrupting transmission by treating contaminated water), and tertiary prevention (reducing impact by treating infected people).
Primary prevention aims to avoid exposure to contaminated water by using safe and reliable water sources or systems for drinking, cooking, washing, or bathing. This can be achieved by implementing measures such as:
- Boiling water before consumption or use to kill pathogens.
- Filtering water before consumption or use to remove pathogens.
- Storing water in clean and covered containers to prevent recontamination.
- Using bottled water or sachet water from trusted sources or brands to ensure quality.
- Avoiding contact with stagnant or polluted water sources or systems to prevent infection.
Secondary prevention aims to interrupt transmission by treating contaminated water sources or systems to make them safe and potable. This can be achieved by implementing measures such as:
- Chlorinating water sources or systems to disinfect them and kill pathogens.
- Adding lime or alum to water sources or systems to coagulate and sediment them and remove pathogens.
- Installing solar disinfection devices or ultraviolet lamps to water sources or systems to inactivate pathogens.
- Applying reverse osmosis or distillation to water sources or systems to purify them and remove pathogens.
- Monitoring and maintaining water quality standards and regulations to ensure safety and quality.
Tertiary prevention aims to reduce impact by treating infected people with appropriate drugs or therapies to cure or alleviate their symptoms. This can be achieved by implementing measures such as:
- Administering antibiotics (drugs that kill bacteria) or antivirals (drugs that inhibit viruses) to infected people with bacterial or viral infections.
- Administering antiprotozoals (drugs that kill protozoa) or anthelmintics (drugs that expel helminths) to infected people with protozoan or helminthic infections.
- Administering oral rehydration solution (a mixture of water, sugar, and salt) or intravenous fluids (fluids given through a vein) to infected people with dehydration or electrolyte imbalance.
- Administering analgesics (drugs that reduce pain), antipyretics (drugs that lower fever), anti-inflammatories (drugs that reduce inflammation), antihistamines (drugs that reduce allergic reactions), or antispasmodics (drugs that relax muscles) to infected people with discomfort or complications.