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What Makes Water Unsafe?

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HealthWiki > A Community Guide to Environmental Health > Chapter 5: Health Problems from Unsafe Water > What Makes Water Unsafe?

Water is unsafe when it contains germs, worms, or toxic chemicals (for more about toxics, see Chapter 16 and Chapter 20). Germs (tiny living things, too small to see, that cause many kinds of illness) and worms, such as whipworm, hookworm, and roundworm, cause many serious illnesses.

Germs and worms live in human and animal waste (urine and feces) and can cause serious and long-lasting illnesses when:

 A woman holds a pitcher of water while drinking from a glass.

  • there is not a good way to get rid of human and animal wastes.
  • water supplies are not protected and kept clean.
  • there is not enough water to wash.

Some of the illnesses they cause, such as cholera, spread quickly and can cause many deaths. Other illnesses from germs and worms can cause years of sickness and lead to other health problems such as dehydration, infections, anemia (weak blood), and malnutrition. Because the most common sign of illnesses from germs and worms is diarrhea, these illnesses are sometimes called diarrhea diseases.

Timothy's Story
Njoki lived in a village with her one-year-old son Timothy. Like the other villagers, she collected water from a tube well built many years before by a development group. Back then, when the pump would break, the development workers brought new parts to repair it. But after the development workers left, no one in the village knew how to repair the pump or where to get parts. And they had no money to buy parts anyway.

So when the pump broke, the women had to go collect water from a water hole outside the village. The water hole was also used by animals, and was contaminated with worms and germs. After drinking water from this hole, Timothy became sick with severe watery diarrhea. He grew weaker and weaker. Njoki had no money to take him to the health center many hours away. Within a few days, Timothy died.

Dehydration from diarrhea diseases is the most common cause of death for children in the world. The discussion of how people get diarrhea diseases continues on the next page.

Understanding why Timothy died

The “But why...?” activity can help to understand the different causes of Timothy’s illness and death.

What caused Timothy’s death? Diarrhea and dehydration.

But why did he have diarrhea? There were germs in the water.

But why were there germs in the water? It was an unprotected water hole contaminated with germs and worms.

But why did Timothy drink from an unprotected water hole? The village pump was broken.

But why couldn’t it be repaired?

A woman speaking.
Continue the “chain” until you run out of questions. You can also return to an earlier link and ask for more underlying causes. For example:

But why didn’t Njoki make the water safe to drink? There was little firewood to boil the water and no money to disinfect it with chlorine.

The “But why...?” questions continue as people come up with reasons for Timothy’s death. A chain of causes drawn on paper or on a chalkboard, or made of cardboard or flannel, can show how each cause is connected to the other causes. For each reason given, a link is added to the chain. In this way, people can understand the different causes of illness, and how these causes can be prevented.

illustration of the below: chain links.

Pump broken
Animal waste in
No wood to boil water
   Timothy gets diarrhea
      No rehydration       drink
money for
Timothy dies
A simple story about how germs travel
illustration of the below: man defecating.
illustration of the below: dog.
EHB Ch5 Page 48-5.png illustration of the below: child with dog.
illustration of the below: mother crouching near child.
1. A man has diarrhea outside. 2. A dog eats the man’s feces. 3. A child plays with the dog and gets feces on his hands. 4. The child starts to cry and his mother comforts him. He wipes his hands on her skirt.
illustration of the below: hand, cloth and griddle.
illustration of the below: man, woman and two children.
illustration of the below: man, woman and two children looking ill.
5. The mother cooks. The germs on her skirt get on her hands. She serves the food with her hands. 6. The family eats the food. 7. Later, the whole family has diarrhea.

How germs and worms spread disease

Sometimes it is easy to know where germs and worms are, especially on unclean things such as feces, rotting foods, dirty toilets, and so on. But sometimes they are in places that look clean, like clear water, or on our hands.

Germs and worms can pass from person to person through touch, and through the air with dust or when people cough or sneeze. They can spread through food and drinking water, or be carried by flies, other insects, and animals. They may also live on uncooked or poorly cooked food. Some worms can be passed by drinking, stepping into, or washing with contaminated water, or eating uncooked shellfish or plants from contaminated water. Germs and worms that cause diarrhea travel on these paths:

arrows showing path of germs from man defecating, to hand, flies, corn stalks and river, to cup and plate of food, to person eating.
One way to remember the paths germs travel is they are all words beginning with the letter F: fingers, flies, feces, fields, foods, and fluids (water).
How diarrhea diseases spread

This activity helps to show how germs that cause diarrhea pass from person to person. People make drawings and put them together to form a story.

Time: 1 to 1 ½ hours

Materials: Small drawing paper, large drawing paper, colored pens or markers, sticky tape, sample drawings

examples of drawings; dirty hands and feet, plate of food covered with flies, man defecating, woman washing plate in stream, and person eating.
  1. Form groups of 5 to 8 people. Each person draws a picture that shows something about how she thinks people get diarrhea. Each drawing should show just one part of the story of how diarrhea spreads. If a person has difficulty drawing, she can write a word instead or get help from someone else. It may help to have sample drawings to stimulate group discussion.
  2. Each person shows her drawing in her small group. The other people in the group tell what they see. This is so every person understands the drawings.
  3. Each group puts their drawings in an order that makes a story about how germs spread. If the group sees there are drawings missing, they make new drawings to fit the story. When the drawings are in order, tape them to a larger piece of paper. Draw arrows between the drawings to make a chart that tells a story of how germs spread.
  4. Each group shows its chart to the other groups. The group showing the drawings tells the story of how diarrhea passes from one person to another.
  5. The whole group discusses the activity. Is every group’s story the same? How are the stories different? Why? Talk about the ways diarrhea spreads. How do economic and social conditions put people at risk? What behaviors and beliefs put people at risk? What other ways do diseases spread that were not illustrated in the activity?

Diarrhea diseases

crouching child having diarrhea.

Most diarrhea diseases are caused by a lack of water for personal cleanliness, toilets that are not clean and safe, and contaminated water and food.


The most common sign of diarrhea disease is frequent, runny or liquid feces. Other signs include fever, headache, trembling, chills, weakness, stomach and intestinal cramps, vomiting, and swollen belly. What treatment to give depends on the kind of diarrhea a person has. These signs can help you know which diarrhea disease a person has:

  • Cholera: diarrhea like rice water, intestinal pain and cramping, vomiting.
  • Typhoid: fever, severe intestinal pain and cramping, headache, constipation or thick diarrhea (like pea soup).
  • Giardia: diarrhea that looks greasy, floats, and smells bad, intestinal pain, low fever, vomiting, gas, burps sometimes smell like rotten eggs.
  • Bacterial dysentery (Shigella): bloody diarrhea 10 to 20 times a day, fever, severe intestinal pain and cramping.
  • Amebic dysentery: diarrhea 4 to 10 times a day, often with white mucus, fever, intestinal pain and cramping, and diarrhea right after eating.
  • Roundworm: swollen belly, weakness, large pink or white worms that may come out in feces or through the mouth and nose.
  • Hookworm: diarrhea, weakness, anemia, pale skin. Children with hookworm may eat dirt.
  • Whipworm: diarrhea, thin pink or grey worms in feces.

To learn more about treating diarrhea diseases and worm infections, see Chapters 12 and 13 in Where There Is No Doctor.

Treatment for diarrhea diseases

Diarrhea is best treated by giving plenty of liquids and food. In most cases, but not all, no medicine is needed. (For more information, see a health worker or a general health book such as Where There Is No Doctor.)

  • Amebic dysentery is best treated with medicines.
  • Typhoid is best treated by antibiotics because it can last for weeks and lead to death.
  • Cholera is best treated with rehydration drink, lots of fluids, and easy-to-digest foods to replace nutrients lost through diarrhea and vomiting. Medicines may be used to prevent cholera from spreading.

If a person has bloody diarrhea, fever, or is very sick, he or she needs to go to a health center right away.

EHB Ch5 Page 52-1.png

Diarrhea and dehydration

Many people die from diarrhea diseases, especially children. Most often, they die because they become dehydrated.

People of any age can become dehydrated, but serious dehydration can happen very quickly to small children and is most dangerous for them.

Any child with watery diarrhea is in danger of dehydration. Give lots of liquids and take young children with signs of dehydration to a health center right away.

EHB Ch5 Page 52-2.png
Signs of dehydration
Sagging of the soft spot in infants
Sunken and tearless eyes
Thirst and dry mouth
weight loss
Little or no urine, or dark yellow urine
Loss of stretchiness of the skin
Lift the skin between two fingers, like this
If the skin does not fall right back to normal, the child is dehydrated.
To prevent or treat dehydration

When a child has watery diarrhea or diarrhea and vomiting, do not wait for signs of dehydration.
Act quickly.

  • Give lots of liquids to drink, such as a thin cereal porridge or gruel, soup, water, or rehydration drink.
  • Keep giving food. As soon as the sick child (or adult) can eat food, give frequent feedings of foods he likes. To babies, keep giving breast milk often — and before any other foods or drinks.
  • Rehydration drink helps prevent or treat dehydration. It does not cure diarrhea, but may support the sick person until the diarrhea stops.

How to make rehydration drink

Here are 2 ways of making rehydration drink. If you can, add half a cup of fruit juice, coconut water, or mashed ripe banana to either drink. These contain potassium, a mineral that helps a sick person accept more food and drink.

Give a child sips of this drink every 5 minutes, day and night, until he begins to urinate normally. A large person needs 3 or more liters a day. A small child usually needs at least 1 liter a day, or 1 glass for each watery stool. Keep giving the drink often, and in small sips. Even if the person vomits, not all of the drink will be vomited. After one day, discard the drink and make a new mixture if necessary.

Made with powdered cereal and salt.

(Powdered rice is best. But you can use finely ground maize, wheat flour, sorghum, or cooked and mashed potatoes.)

WWHND ChSk Page 540-2.png
WWHND ChSk Page 540-3.png
In 1 liter of clean WATER put half of a level teaspoon of SALT,

and 8 heaping teaspoons of powdered CEREAL.
EHB Ch5 Page 53-5.png

Boil for 5 to 7 minutes to form a liquid gruel or watery porridge. Cool the drink quickly and begin to give it to the sick person.

CAUTION! Taste the drink each time before you give it to make sure that it has not spoiled. Cereal drinks can spoil within a few hours in hot weather.

Made with sugar and salt.

(You can use raw, brown or white sugar, or molasses.)

WWHND ChSk Page 540-3.png
WWHND ChSk Page 540-2.png
In 1 liter of clean WATER put half of a level teaspoon of SALT,

and 8 level teaspoons of SUGAR .
Mix well.
EHB Ch5 Page 53-4.png
CAUTION! Before adding the sugar, taste the drink and be sure it is less salty than tears.

IMPORTANT! If dehydration gets worse or other danger signs appear, get medical help.
Stop the spread of diarrhea

This activity uses the stories from the activity “How diarrhea diseases spread” to show how to prevent diarrhea from being spread.
Time: 30 minutes to 1 hour
Materials: large sheet of drawing paper, colored pens or markers, sticky tape, pictures from the activity “How diarrhea diseases spread”

EHB Ch5 Page 54-1.png
  1. Work in the same small groups as in the previous activity, “How diarrhea diseases spread.” Each group looks at the pictures from “How diarrhea diseases spread.” They then talk about how to stop the spread of disease by washing hands, using toilets, protecting food and water, and so on. Each of these actions is a barrier that blocks the spread of diarrhea.
  2. When the group has agreed on what barriers will stop the spread of germs, have the group draw pictures that show the different ways to stop the spread of diarrhea diseases.
  3. The group then talks about how to change the story from “How diarrhea diseases spread” to “Stop the spread of diarrhea.” Where do the new drawings fit in the story so that they will stop the spread of illness? The new drawings are taped in place in the old story to show how the story can change.
  4. Each group shows its new stories. The whole group talks about which disease barriers they use and which ones they do not use. Do all the disease barriers work all the time? Why, or why not? Why is it hard to use some of these barriers? How can the community work together to make sure that diarrhea diseases do not spread?
EHB Ch5 Page 54-2.png

Guinea worm

Guinea worm is a long, thin worm that lives under the skin and makes a painful sore on the body. The worm, which looks like a white thread, can grow to be more than 1 meter long. Guinea worm is found in parts of Africa, India, and the Middle East.


A painful swelling usually on the ankle or leg, but can develop elsewhere on the body. A few days to a week later, a blister forms which then quickly bursts open and forms a sore. This often happens when standing in water or bathing. The end of a white thread-like guinea worm can be seen poking out of the sore. The worm works its way out of the body over the next week. If the sore gets dirty and infected, or if the worm is broken by trying to pull it out, the pain and swelling spread and walking can become very difficult.

Guinea worm is spread from person to person like this:

EHB Ch5 Page 55-1.png

1. An infected person with an open sore wades into a water hole. The worm pokes out of the sore and lays eggs in the water.
2. Tiny water fleas eat the worm eggs.
3. Another person drinks the water and swallows the fleas and the worm eggs in the water.
4. Some of the eggs develop slowly into worms under the skin. After a year, a sore forms when a worm breaks through the skin to lay eggs.

To treat guinea worms, see a health worker or a general health book such as Where There Is No Doctor. Also, take steps to prevent new contact with worms.

To prevent guinea worms, protect water sources and filter water. If nobody wades or bathes in water used for drinking, the infection cannot be passed on and will eventually disappear from the area.

Blood flukes (schistosomiasis, bilharzia, snail fever)

This infection is caused by a kind of worm that gets into the blood through the skin after wading, washing, or swimming in contaminated water. The illness can cause serious harm to the liver and kidneys, and may lead to death after months or years. Women have a greater risk of infection from blood flukes because they spend a lot of time in and around water — collecting it, washing clothes, and bathing children.

Sometimes there are no early signs. A common sign in some areas is blood in the urine or in the feces. It can also cause genital sores in women. In areas where this illness is very common, even people with only mild signs or belly pain should be tested.

EHB Ch5 Page 56-1.png

Blood flukes spread like this:

1. Infected person urinates or defecates in water.
2. Urine or feces has worm eggs in it.
3. Worm eggs hatch, and worms go into snails.
4. Young worms leave snail and go into another person.
5. In this way, someone who washes or swims in water where an infected person has urinated or defecated also becomes infected.

Blood flukes are best treated with medicines. See a health worker about which medicines to use, or a general health book such as Where There Is No Doctor. Genital sores and blood in the urine are also signs of sexually transmitted infections (STIs). Some women will not seek treatment because they are afraid they will be blamed for having an STI. Lack of treatment can cause other serious infections and can make women infertile (unable to become pregnant).


Blood flukes are not passed directly from one person to another. For part of their life, the blood flukes must live inside a certain kind of small water snail. Community programs can be organized to kill these snails and prevent blood flukes. These programs work only if people follow the most basic preventive step: never urinate or defecate in or near water.