Germs are in the air and in our food, on door handles and dinner plates, in our bodies and on our pets. Germs like viruses and bacteria are everywhere. Some are harmless, but others can make you very sick. Viruses and bacteria can cause a range of illnesses and diseases, from the common cold to tuberculosis (TB). Viruses and bacteria are all around us, but many people–kids and adults–don't understand much about how germs can affect our health. What does a virus do to your body? How can people catch diseases from bacteria? How can you keep yourself safe from diseases that some germs carry? As you read, you'll find answers to all of these questions and more!