1 00:00:00,000 --> 00:00:08,000 Hi. I'm Kaylee, one of the treehouse detectives. You must be Dr. Beck-Saget. 2 00:00:08,000 --> 00:00:10,000 Yes, I am. How can I help you? 3 00:00:10,000 --> 00:00:16,000 My friend Jacob is planning a vacation, but he's worried that he might get sick and not be able to go. 4 00:00:16,000 --> 00:00:18,000 We're trying to think of ways to keep him healthy. 5 00:00:18,000 --> 00:00:22,000 So we figured that we needed to know more about diseases and how people get sick. 6 00:00:22,000 --> 00:00:24,000 Well, you've come to the right place. 7 00:00:24,000 --> 00:00:27,000 I'm a detective, too, of sorts. A medical detective. 8 00:00:27,000 --> 00:00:32,000 And I work here at the Centers for Disease Control and Prevention, or CDC for short. 9 00:00:32,000 --> 00:00:34,000 What sort of detective work do you do? 10 00:00:34,000 --> 00:00:42,000 Medical epidemiology. That means I investigate how infectious diseases spread through a population and how to stop the spread. 11 00:00:42,000 --> 00:00:49,000 But CDC does epidemiology of many other things, including prevention of birth defects and prevention of injuries. 12 00:00:49,000 --> 00:00:52,000 What exactly is an infectious disease? 13 00:00:52,000 --> 00:00:57,000 First, you need to know a little bit about bacteria, viruses, and other microorganisms. 14 00:00:57,000 --> 00:01:05,000 As we're standing here, we are not alone. We are covered inside and out with millions of microorganisms. 15 00:01:05,000 --> 00:01:10,000 What are microorganisms? With millions of them, I hope they're not all bad. 16 00:01:10,000 --> 00:01:14,000 Well, that word is just taken from a Latin word that means tiny living beings. 17 00:01:14,000 --> 00:01:20,000 And no, they're not all bad. Most of them are harmless. And some of them are even very helpful to us. 18 00:01:20,000 --> 00:01:24,000 That's good. Are viruses and bacteria microorganisms? 19 00:01:24,000 --> 00:01:28,000 Yes. Some microorganisms are one-celled. They're called bacteria. 20 00:01:28,000 --> 00:01:32,000 You can't see them with the naked eye, but you can see them with a light microscope. 21 00:01:32,000 --> 00:01:36,000 Viruses are so small that they can only be seen with an electron microscope. 22 00:01:36,000 --> 00:01:39,000 Other than size, how do bacteria differ? 23 00:01:39,000 --> 00:01:46,000 Bacteria have cell walls and nucleus with both DNA and RNA, which are the building blocks for replicating. 24 00:01:46,000 --> 00:01:50,000 Viruses only have DNA or RNA, not both. 25 00:01:50,000 --> 00:01:57,000 Another difference is that there are medicines called antibiotics that can cure most infectious diseases caused by bacteria. 26 00:01:57,000 --> 00:02:02,000 However, there are very few medicines that can treat diseases caused by viruses. 27 00:02:02,000 --> 00:02:05,000 How does a person get an infectious disease? 28 00:02:05,000 --> 00:02:10,000 By being exposed to a bacteria or virus. But not everyone who is exposed gets infected. 29 00:02:10,000 --> 00:02:12,000 Why not? 30 00:02:12,000 --> 00:02:19,000 When a microorganism gets past the body's defense mechanisms, then the person may become infected and they may become sick. 31 00:02:19,000 --> 00:02:21,000 This is called an infectious disease. 32 00:02:21,000 --> 00:02:29,000 We've all had infectious diseases in our lives. Colds, pneumonia, chicken pox, and even some cancers. 33 00:02:29,000 --> 00:02:32,000 Sounds like infectious diseases are very serious. 34 00:02:32,000 --> 00:02:39,000 Yes, some are. Infectious diseases kill more people on Earth than wars and accidents causing injuries. 35 00:02:39,000 --> 00:02:45,000 Yet some are so mild that after a little scratchy throat or a dry patch of skin, they're gone. 36 00:02:45,000 --> 00:02:46,000 How do they spread? 37 00:02:46,000 --> 00:02:48,000 Some are spread by food or water. 38 00:02:48,000 --> 00:02:53,000 If people drink or eat contaminated food or water, then they may become infected. 39 00:02:53,000 --> 00:02:55,000 Others are spread through the air. 40 00:02:55,000 --> 00:03:01,000 When a person speaks or coughs, the microorganisms become airborne and then other people breathe them in. 41 00:03:01,000 --> 00:03:04,000 So that's why it's important to cover your mouth when you cough. 42 00:03:04,000 --> 00:03:08,000 Yes, and many others are spread through direct contact. 43 00:03:08,000 --> 00:03:16,000 So if a person has pink eye or a cold and they touch their eye or nose and then they touch another person's hand, they can transmit those microorganisms. 44 00:03:16,000 --> 00:03:19,000 So that's why it's important to wash your hands often. 45 00:03:19,000 --> 00:03:21,000 Yes, especially before eating. 46 00:03:21,000 --> 00:03:28,000 Just 15 seconds of washing your hands with warm water and soap can prevent so much spread of infectious diseases. 47 00:03:28,000 --> 00:03:30,000 Thanks, Dr. Beksage. 48 00:03:30,000 --> 00:03:31,000 You're welcome.