So as we think about sanitation, there are several options available. In general, I think they can be broken into four categories: defecation fields or zones, communal latrines, family or group latrines and flush toilets. Defecation fields or defecation zones are just places that are reserved for people to defecate in. And if you look carefully in this picture, you'll notice some little brown turds out there on the sand. And this is a - a slum outside of Lima, Peru - Los Pampas de San Juan de Miraflores - and there's some power lines here. And the mist camp comes in off the ocean and makes a zzz, zzz, zzz crackling noise and people just did not want to live under those power lines. So no one was living there and people would go out and defecate there in the nighttime. And in this very dry environment, where they only get two centimeters of rain a year, a defecation field works very well. Within an hour or two, the outside layer of each of those stools you can see would be completely dried out. And if a fly were to land on it, it wouldn't be able to pick up any active or viable bacteria or virus. By the end of a day, that stool would be dry right through. And so if someone was to step on the stool, they wouldn't pick up any viable bacteria or viruses. So wow, works pretty well. In this particular case, it actually doubles as a - a football field in the daytime hours and a defecation field at night. That might be a little disgusting, but we'll let that slide for the moment. So there are lots of options for latrines. So here's a very nice composting latrine that's been made by Oxfam in Ethiopia. And wow, this is a great, great latrine. It is set up so it's easy to shovel the feces out every few months and they are going to put it out on gardens and use it as fertilizer. Wow, that's great. Most latrines are just holes in the ground and people have put something over it so that they can stand over that pit and deposit their feces. And most cultures have some form of wall or privacy-inducing material around the latrine; but in different cultures, that need may vary. So here is something referred to as a VIP latrine, a ventilated improved pit latrine. It is the best thing that's happened to pooping since Thomas Crapper invented the flush toilet. This is just a great, great device. If built properly, as these ones are, there will be a vent pipe on the sunny side of the latrine. And that vent pipe will, in the daytime hours, get warm. And if we look at this little graphic - if that vent pipe is warm, well, the air in it will get warm and hot air rises. And so air will be drawn out of the pit up that vent pipe. Well, if built properly, there will be only air coming into the pit through the squat hole, sort of the place where it says air currents, about in the middle of that image. And as people are defecating there, air will be flowing downwards into the pit. So even if the floor is dirty, there will be no odors. What a glorious, glorious thing. And if built properly, as this last image was, there will be a barrier wall that you walk around so there's no direct sunlight going down through the squat hole, but there is sunlight coming down through the vent pipe. And flies, which are just uncontrollably drawn to your feces and uncontrollably drawn to other things like your food, are also drawn to light. And so if a fly does happen to get down into the pit, it is drawn to go up the vent pipe rather then up into the latrine. And when built properly, there will always be a little screen on the top of the vent pipe and the flies will get trapped behind the screen. And often there'll be a little tiny lizard in there that will be gobbling up the fly. So it controls odors, controls flies - what a great, great thing. So now, when we're struggling with the issue of sanitation, we have a huge problem. And that huge problem is what you would call children. Now, I know some of you might like children. I don't know, it's even possible some of you once were children. But for the sanitarian, these self-propelled fecal dispensing units are just the bane of one's existence. They are terrible, terrible, terrible. First of all, they don't yet know that they should be embarrassed and ashamed of defecating, that they're not blessed with that knowledge yet. So let's just do it anywhere. That's bad. Secondly, on any given day in the world's poorest settings, a small child is many, many times more likely, maybe 10 or 20 times more likely, to have diarrhea and to have a pathogen coming out in their stool than an adult's poop. So they have the deadliest poop, they spread it willy nilly. Something needs to be done to control children's poop if you're going to deal with it. And here, actually - I don't know if you can tell, but the perfect thing is happening. This little girl said I've got to go, I got to go, I got to go. So she's gone with her brother and they're right next to a latrine and she's going to defecate and he's going to then take a banana leaf or a piece of cardboard and scoop it up and throw it in latrine. That is the perfect solution. So realize we can build all the latrines we want, but if most of the dangerous pathogens are coming out of little kids, a key part of making this whole thing work for preventing diarrhea is making sure that adults know small children's feces is dangerous and it needs to be deposited in a safe manner. Here's another one of those VIP latrines. And now I'm really happy to see this. Here's a little kid. They're pooping right outside and mom's going to scoop it up. She's going to put in the toilet. This is just everything looking like it's working perfectly. But if we look inside this toilet, it turns out that someone - and you can tell I have a bad attitude about kids - so probably a little kid has pooped on the floor in this toilet. And if you look carefully on the wall above it, now there's flies inside this latrine that was designed to control flies. And the next person who comes along that doesn't want to walk around that barrier where it's kind of dark and a little bit scary, they're not going to step in that feces. So they're going to deposit their feces somewhere a little closer and then someone else is going to deposit and you can imagine, at the end of a couple of weeks, this is going to be a really, really dirty, unsanitary place. And this reminds me of the point that the world over, a communal latrine is a dirty latrine unless it's someone's job to keep it clean. Maybe you have to pay them, maybe you have to call upon their sense of civic duty; but somehow, if you're going to have communal latrines as the solution to your sanitation needs, you need to have a program designed to keep them maintained and clean. So this idea of a latrine or a toilet, a pit latrine, even can operate on a building. So here is an apartment building and out beside that apartment building in Indonesia, here is a septic tank. That is a big pit, just like the pit for a latrine, only much, much bigger. And when people flush their toilet, when people run water in their sink, it goes down into here. This is very sandy soil, so the water seeps away and the solids are left behind. And you can see that there are some entry ways so that a truck can come along and vacuum out the sludge in there every few months. And same idea as a pit latrine, only this is for an apartment building. There are very few acute crises where the flush toilet, running water options, that many of us in the West live with are a viable option. Often there's not enough water available to make such a system viable and also, there's a lot of resources per capita into setting up a flushed water toilet-type system. So it - in emergencies, it's very, very rarely an option, but it often happens that we're working on the edge of emergency for where lots and lots of people are in apartments and have flush toilets. There are a variety of things that are done to deal with that sewage. It's way beyond the ability of us in our - our short conversation to address that; but the two most popular things in the world's poorest countries are just to dump it somewhere like in a river or in the ocean - and that's not very good; or to let it run through some lagoons, which are a very effective way of treating sewage that's relatively low technology and not very expensive to maintain and operate, but that require a lot of land. Interestingly, on the left in front of you is a sewage lagoon in that shantytown that I showed you pictures of before back in 1990 when I lived there for a year; and now it - on the right is a Google Earth picture of the same lagoon system, which is now six times as large. It had to grow as more and more people in Lima got flush toilets. So realize it's an option. It is probably going to be specialists who deal with that. That's not something a small NGO would generally address. On the other hand, an integral part of sanitation is hand-washing. After people defecate, they need to be able to wash their hands, whether they've clean their backside with leaves or paper or wiped it with their hand - it doesn't matter. People acquire a lot of fecal contamination in the defecating process and getting them to wash their hands after they defecate, getting them to wash their hands before they touch or prepare food for others, is pretty darn effective as we saw from our reviews. And there are a lot of ways that this can be organized and those ways depend on the culture and what's sustainable and will people steal things - can I leave soap beside my hand-washing - devices? If it's at my house, I probably can; if it's in a public place, I probably can't. So all of these things need to be in equilibrium with the culture in which they are being used. So UNICEF has, in a big way, gotten into hygiene education through schools for children. And there are a lot of hand-washing programs out there or promoting hand-washing. And it's funny; hand-washing is a funny thing, in that most reviews of hand-washing programs by NGOs show no benefit. And this happens again and again; almost always, those results are hidden. They don't appear in the published literature and yet like clockwork, like we saw in that Karen Cross review, when you do some sort of analysis of people who wash their hands or monitor how much soap people consume over time and compare them to their neighbors, the people who wash their hands have way less diarrhea in themselves and in their children. So it's not completely clear what's happening here. Is hand-washing, is soap ownership a tool for cutting down on fecal movement across your hands to your mouth? Or is hand-washing behavior and the ownership of soap a marker for people who understand transmission dynamics and all of the things that need to happen in order to prevent fecal oral transmission? It is not clear to me what the mechanisms are. Just realize, hand-washing is really good; if you try to induce it through some sort of program, not very likely you're going to change the fecal-oral dynamics in your community in the short term. And if UNICEF strategy of getting children to be hand-washers and latrine-users will alter their behavior over their lifetime and make things more sanitary, that I don't know, but it seemed like a noble pursuit and a very reasonable thing to be doing. There is little regret in it and probably benefits to be had.
