 Dr. Ogan. In this video I want to cover a couple more terms that are very important to understanding where, when, and how diseases spread or the occurrence of disease. So we're going to talk about sporadic diseases, endemic diseases, epidemic diseases, and pandemic diseases. Let's start with sporadic diseases. These are ones that only occur occasionally. They kind of pop up. There's no geographical location associated with them. So I would say tetanus, rabies, even the plague are examples of sporadic diseases. So you might see just a handful of cases popping up, again, with no, like, geographical boundaries. So that's a sporadic disease. And endemic disease is a disease that's constantly present in the population. So sadly the first thing that comes to mind would be malaria in some parts of Africa. It is just endemic to those regions. It's always there. Same thing with HIV infection in, let's say, Sub-Saharan Africa. All right. So those are examples of endemic diseases that are constantly present in a population. Epidemic diseases are diseases that just explode in a given area in a short period of time. So it could be a very small area, like a single town having some sort of an outbreak, or it could be a much larger area, but those are epidemics. So diseases that explode and increase in number or incidence very quickly. So I think about maybe your flu seasons generally might be an epidemic, like I was just reading something about Australia's flu season ending. I'm recording this video and heading into winter where I live in South Dakota. And Australia's flu season is gone already. But then we'll take our turn and we'll have our flu season. So maybe we'll have an epidemic flu season here where I live. So that would be an epidemic disease. And then a pandemic disease would be a worldwide epidemic. So speaking of the flu, the flu pandemic of 1918 killed 30 to 50 million humans, 600,000 Americans. So that was a worldwide epidemic that was affecting everyone over a relatively short period of time. All right. So sporadic diseases, they just pop up sporadically like name implies. Endemic diseases are constantly present. Epidemic diseases, you see an explosion in number of a disease in a given area. And again, that could be a continent or a city. Epidemic diseases would be worldwide epidemics. All right. I hope this helps. Have a wonderful day. Be blessed.