Disease

Ndasiona Joshua has scabies which thrives in the absence of clean water to wash with.

Credit: WaterAid / Jon Spaull

Over a billion people in the world do not have access to safe water and over two billion lack adequate sanitation. As a result a child dies every 15 seconds from easily preventable diseases.

This page outlines the most prevalent of these diseases. It explains what they are, how they are spread and how they can be prevented.

What causes diseases?

Diseases are caused by micro-organisms called pathogens. These can be divided into the following groups:

• Viruses are very small and generally do not survive for long outside the human body. Among other diseases viruses cause infectious hepatitis and polio.

• Bacteria need moisture, warmth, food and time to multiply and survive. Diseases they cause include cholera and typhoid.

• Protozoa are single celled micro organisms capable of some movement. They cause diseases including dysentery and giardiasis.

• Helminths (parasitic worms) are large and do not survive for long outside a person's body. However they lay eggs, some of which are very good at surviving harsh conditions. Worms cause bilharzia, guinea worm and hookworm infections.

The main water and sanitation related diseases can be divided into three groups:

Diarrhoeal

Parasitic

Water washed 

These can all be prevented through our work providing clean water, effective sanitation and good hygiene.

Factfile

• Children in developing countries commonly carry up to 1000 hookworms, roundworms and whipworms at a time causing anaemia, stunted growth and other debilitating conditions.
• One gram of faeces can contain 10,000,000 viruses, 1,000,000 bacteria, 1000 parasite cysts and 100 parasite eggs.
• Seven out of 10 childhood deaths in developing countries can be attributed to just five main causes: pneumonia, diarrhoea, measles, malaria and malnutrition.

Download the diseases issue sheet ( PDF 196Kb)