Lack of sanitation is a huge global health problem with deadly consequences.

Most people prefer not to think about what happens to all the stuff we flush down the toilet. As the saying goes: out of sight, out of mind. That said, many people in the world don’t have this luxury.

In fact, 2.6 billion people live in environments utterly devoid of sanitation.

This doesn’t mean they’re forced to use a public toilet or even a dirty old outhouse that empties into a drain. It means that 2.6 billion people have no access to a toilet of any kind. They have to defecate where they can – in public, in the woods or even in plastic bags which they then discard in the narrow alleyways of overcrowded slums.

People in such conditions constantly walk on feces and get it on their clothes, which can result in it getting into food and drinking water.

And this is just the tip of the iceberg. Just consider this upsetting fact: Four out of ten people live every day in the midst of human excrement.

This global sanitation shortage causes a staggering amount of disease: One out of every ten illnesses in the world can be traced back to a lack of sanitation, which can lead to anything from poor hygiene to contaminated water. In fact, the number of children who have died from diarrhea in the past decade is greater than the combined death toll of all armed conflict since World War II.

The reason for this is simple. One gram of feces can contain ten million viruses, one million bacteria, 1000 parasite cysts and 100 worm eggs – and sanitation experts estimate that people living without sanitation sometimes consume as much as ten grams of fecal matter in one day.

The result of this?

Every 15 seconds, a child dies from diarrhea. And since approximately 90 percent of diarrhea is due to fecally contaminated food or water, it’s no wonder that UNICEF considers it the biggest barrier to survival for a small child in a developing country, more of threat than AIDS, tuberculosis or malaria.