Germs are found all over the world, in all kinds of places. There are four major types of germs: bacteria, viruses, fungi, and protozoa. They can invade plants, animals, and people, and sometimes they make us sick. Bacteria are tiny, single-celled organisms that get nutrients from their environments. In some cases, that environment is your child or some other living being. Some bacteria are good for our bodies - they help keep the digestive system in working order and keep harmful bacteria from moving in. Some bacteria are used to produce medicines and vaccines. Viruses can't survive, grow, and reproduce unless a person or an animal puts up rental space. Viruses can only live for a very short time outside other living cells. For example, they can stay on surfaces like a countertop or toilet seat in infected bodily fluids for a short period of time, but they quickly die there unless a live host comes along. Once they've moved into someone's body, though, viruses spread easily and can make a person sick. Viruses are responsible for some disease like cold smallpox and AIDS Fungi are multi-celled, plant-like organisms that usually aren't dangerous in a healthy person. Fungi get nutrition from plants, food, and animals in damp, warm person. Fungi get nutrition from plants, food, and animals in damp, warm infections. People who have weakened immune systems (from diseases like HIV or cancer) may develop more serious fungal infections. Protozoa are, like bacteria, one-celled organisms. Protozoa love moisture, so intestinal infections and other diseases they cause are often spread through contaminated water.
