12.4 Waterborne Diseases

This topic explains waterborne diseases — diseases caused by drinking or using contaminated water — and describes some common examples.

Definition

Waterborne diseases are diseases caused by pathogens (harmful microorganisms) that are transmitted through water.

Simple explanation: Waterborne diseases are illnesses you can get from drinking or using dirty water.

Main Idea

• Typhoid fever
• Dysentery
• Hepatitis

Chemical and bacterial contents in livestock waste can pollute surface and groundwater, causing the above-mentioned diseases.

Hepatitis — a viral disease — occasionally spreads through drinking water.

Unclean water supplies, poor sanitation, and poor hygiene kill 2,668,000 people worldwide each year.

Water in swimming pools is purified from pathogenic organisms by aeration and chlorination.

Simple explanation: Dirty water spreads diseases; clean water and good hygiene save lives.

Core Concept

Common Waterborne Diseases

Detailed Explanation

How Waterborne Diseases Spread

• Human waste — dumped on the ground or into streams.
• Livestock waste — contains bacteria and chemicals.
• Sewage — carries pathogens, bacteria, viruses.
• Poor sanitation — allows pathogens to enter water supplies.

• Drinking contaminated water.
• Eating food washed with contaminated water.
• Swimming in contaminated water.
• Poor hygiene (not washing hands).

Simple explanation: Pathogens in water get into our bodies when we drink, eat, or swim in contaminated water.

Dysentery

Cause: A parasite, Entamoeba.

How it spreads: The infection is transmitted by fecal contamination of water or food by the encysted organism.

• Mild to severe abdominal cramps
• Diarrhea
• Chocolate-coloured stool with mucous
• Sometimes blood in stool

Simple explanation: Dysentery is an intestinal disease caused by a parasite, spread through contaminated water or food.

Jaundice

Cause: Obstruction of the liver.

How it happens: Excess of bile from the liver enters the blood.

• Yellowness of skin and eyes
• Loss of appetite
• Weakness
• Fatigue

Simple explanation: Jaundice makes your skin and eyes turn yellow because of liver problems.

Hepatitis

Cause: Viruses (classified as Hepatitis A, B, C, D, and E).

How it spreads: Hepatitis A and E spread through polluted water.

• Inflammation of the liver
• Jaundice
• Fatigue
• Nausea
• Abdominal pain

Note from the book: > "Hepatitis a viral disease occasionally spreads through drinking Water."

Simple explanation: Hepatitis is a viral liver disease; types A and E spread through polluted water.

Typhoid

• Salmonella typhi
• Salmonella paratyphi
• Salmonella enteritidis

How it spreads: Through polluted water containing these bacteria.

• Continuous fever between 101 °F to 104 °F
• Irregular pulse

Simple explanation: Typhoid is a serious intestinal disease caused by bacteria in polluted water, with a high continuous fever.

DO YOU KNOW? (from the Book)

> "Chlorination is not effective against viruses such as those that cause hepatitis."

This means that chlorination alone may not be enough to make water safe from all viruses. Additional treatment methods may be needed.

Simple explanation: Chlorine kills bacteria but not all viruses — so water treatment must be done carefully.

Society, Technology and Science (from the Book)

Water treatment is essential for many reasons:

> "Through water purification, we can avoid drinking impure and contaminated water, which causes many epidemic diseases and is unsafe for healthy life. It removes bacteria, viruses and parasites which may cause diarrhoea, dysentery, botulism, typhoid, cholera, polio, and hepatitis. It also removes heavy metals like As, Cr and Pb which can cause long term neurological problems, kidney diseases, nausea, dizziness, and cancer. It also improves the flavor and appearance."

Simple explanation: Water treatment removes harmful microbes and heavy metals, preventing diseases and improving water quality.

Concept Assessment Exercise 12.1 (from the Book)

1. List some waterborne diseases.

• Dysentery
• Jaundice
• Hepatitis
• Typhoid
• Cholera
• Diarrhea

2. List sources of waterborne diseases.

• Human waste
• Livestock waste
• Sewage
• Poor sanitation
• Contaminated water supplies

3. List steps used in raw water treatment.

• Sedimentation
• Coagulation
• Filtration
• Chlorination

Intermediate Level

How Waterborne Diseases Spread

Diseases in Detail

• Caused by Entamoeba (parasite).
• Spreads through fecal contamination of water or food.
• Symptoms: abdominal cramps, diarrhea, chocolate-coloured stool with mucous, sometimes blood.

• Caused by obstruction of the liver.
• Excess bile enters the blood.
• Symptoms: yellowness of skin and eyes, loss of appetite, weakness, fatigue.

• Caused by viruses (A, B, C, D, E).
• Hepatitis A and E spread through polluted water.
• Symptoms: inflammation of the liver, jaundice, fatigue, nausea.

• Caused by Salmonella bacteria.
• Spreads through polluted water.
• Symptoms: continuous fever (101–104 °F), irregular pulse.

Why Chlorination Is Not Enough

• Chlorination is effective against bacteria.
• But it is not effective against all viruses (e.g., hepatitis virus).
• Additional treatment methods may be needed:
• UV treatment
• Ozonation
• Reverse osmosis
• Boiling

Simple explanation: Chlorine kills bacteria but not all viruses — additional treatment is sometimes needed.

Global Impact of Waterborne Diseases

Unclean water supplies, poor sanitation, and poor hygiene kill 2,668,000 people worldwide each year.

This shows the importance of clean water and proper sanitation.

Simple explanation: Millions of people die each year from diseases caused by dirty water — clean water saves lives.

Prevention of Waterborne Diseases

Important Points

• - Waterborne diseases: diseases caused by pathogens transmitted through water.
• - Common waterborne diseases: dysentery, jaundice, hepatitis, typhoid.
• - Dysentery: caused by Entamoeba parasite; spread by fecal contamination.
• - Jaundice: caused by liver obstruction; yellowness of skin and eyes.
• - Hepatitis: caused by viruses (A, B, C, D, E); Hepatitis A and E spread through polluted water.
• - Typhoid: caused by Salmonella bacteria; continuous fever 101–104 °F.
• - Unclean water supplies, poor sanitation, and poor hygiene kill 2,668,000 people worldwide each year.
• - Chlorination is not effective against all viruses (e.g., hepatitis).
• - Prevention: water treatment, chlorination, boiling, proper sanitation, handwashing.

Remember

• - Waterborne diseases = diseases from contaminated water.
• - Dysentery → Entamoeba parasite.
• - Jaundice → liver obstruction; yellow skin.
• - Hepatitis → viruses; liver inflammation.
• - Typhoid → Salmonella bacteria; high fever.
• - Chlorination → kills bacteria, not all viruses.
• - Prevention: water treatment, sanitation, handwashing.
• - 2,668,000 deaths/year from unclean water.

Common Mistakes

• 1. Thinking all waterborne diseases are caused by bacteria. Some are caused by viruses (hepatitis) or parasites (dysentery).
• 2. Thinking chlorination kills all pathogens. It kills bacteria but not all viruses.
• 3. Confusing hepatitis A and E with other types. Hepatitis A and E spread through polluted water; B, C, D spread through other routes.
• 4. Thinking jaundice is a disease. Jaundice is a symptom (yellowness of skin and eyes) caused by liver problems.
• 5. Thinking waterborne diseases only affect developing countries. They occur worldwide, especially where sanitation is poor.
• 6. Forgetting the importance of handwashing. Handwashing is one of the simplest and most effective ways to prevent waterborne diseases.

Quick Revision

• Waterborne diseases: diseases caused by pathogens transmitted through contaminated water.
• Sources: human waste, livestock waste, sewage, poor sanitation.
• Common waterborne diseases:
• Unclean water supplies, poor sanitation, and poor hygiene kill 2,668,000 people worldwide each year.
• Chlorination is not effective against viruses such as those that cause hepatitis.
• Water in swimming pools is purified from pathogenic organisms by aeration and chlorination.
• Water treatment is essential: removes bacteria, viruses, parasites, and heavy metals; improves flavor and appearance.

60-Second Revision

• Waterborne diseases = diseases from contaminated water.
• Dysentery → Entamoeba parasite.
• Jaundice → liver obstruction; yellow skin.
• Hepatitis → viruses; liver inflammation.
• Typhoid → Salmonella bacteria; high fever.
• Chlorination → kills bacteria, not all viruses.
• Warning: unclean water kills 2,668,000 people worldwide each year.