What Are Germs? The term "germs" refers to the microscopic bacteria, viruses, fungi, and protozoa that can cause disease. Washing hands well and often is the best way to prevent germs from leading to infections and sickness. What Are the Types of Germs? Bacteria Bacteria (bak-TEER-ee-uh) 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 make medicines and vaccines. But bacteria can cause trouble too, as with cavities, urinary tract infections, ear infections, or strep throat. Antibiotics are used to treat bacterial infections. Viruses Viruses are even smaller than bacteria. They aren't even a full cell. They are simply genetic material (DNA or RNA) packaged inside of a protein coating. They need to use another cell's structures to reproduce. This means they can't survive unless they're living inside something else (such as a person, animal, or plant). Viruses can only live for a very short time outside other living cells. For example, viruses in infected body fluids left on surfaces like a doorknob or toilet seat can live there for a short time. They'll die quickly unless a live host comes along. When they've moved into someone's body, though, viruses spread easily and can make a person sick. Viruses cause minor sicknesses like colds, common illnesses like the flu, and very serious diseases like smallpox or HIV/AIDS. Antibiotics are not effective against viruses. Antiviral medicines have been developed against a small, select group of viruses. Fungi Fungi (FUN-guy) are multicelled, plant-like organisms. A fungus gets nutrition from plants, food, and animals in damp, warm environments. Many fungal infections, such as athlete's foot and yeast infections, are not dangerous in a healthy person. People with weak immune systems (from diseases like HIV or cancer), though, may get more serious fungal infections. Protozoa Protozoa (pro-toe-ZO-uh) are one-celled organisms, like bacteria. But they are bigger than bacteria and contain a nucleus and other cell structures, making them more like plant and animal cells. Protozoa love moisture. So intestinal infections and other diseases they cause, like amebiasis and giardiasis, often spread through contaminated water. Some protozoa are parasites. This means they need to live on or in another organism (like an animal or plant) to survive. For example, the protozoa that causes malaria grows inside red blood cells, eventually destroying them. Some protozoa are encapsulated in cysts, which help them live outside the human body and in harsh environments for long periods of time. Back to Articles Related Articles Hand Washing: Why It's So Important Washing your hands well and often is the best way to keep from getting sick. Here's how to teach this all-important habit to your kids. Read More Fighting Germs Bacteria, viruses, fungi, and protozoa can cause disease. Here's how to help protect your family from germs. Read More What Is an Ear Infection? A middle ear infection happens when germs like bacteria and viruses get in your middle ear and cause trouble. Read this article to find out more. Read More Coronavirus (COVID-19) The coronavirus (COVID-19) is making people sick with flu-like symptoms. Read this article to learn how to protect your family, and to know when to call your doctor. Read More Food Poisoning Sometimes, germs can get into food and cause food poisoning. Find out what to do if your child gets food poisoning - and how to prevent it. Read More E. Coli Undercooked burgers and unwashed produce are among the foods that can harbor E. coli bacteria and lead to infection marked by severe diarrhea. Here's how to protect your family. Read More Why Do I Need to Wash My Hands? Washing your hands is the best way to stop germs from spreading. Learn all about the best way to wash your hands in this article for kids. Read More Hand Washing: Why It's So Important Did you know that the most important thing you can do to keep from getting sick is to wash your hands? If you don't wash your hands frequently, you can pick up germs from other sources and then infect yourself. Read More Campylobacter Infections These bacterial infections can cause diarrhea, cramping, abdominal pain, and fever. Good hand-washing and food safety habits can help prevent them. Read More Shigella Infections (Shigellosis) Shigella are bacteria that can infect the digestive tract and cause a wide range of symptoms, from diarrhea, cramping, vomiting, and nausea, to more serious complications and illnesses. Read More E. Coli Undercooked burgers and unwashed produce are among the foods that can harbor E. coli bacteria and lead to infection and severe diarrhea. Here's how to protect yourself. Read More Coxsackievirus Infections Coxsackievirus infections can spread from person to person. In most cases, the viruses cause mild flu-like symptoms, but can lead to more serious infections. Read More MRSA MRSA is a type of bacteria that the usual antibiotics can't tackle anymore. The good news is that there are some simple ways to protect yourself from being infected. Find out how. Read More MRSA MRSA is a type of bacteria that the usual antibiotics can't tackle anymore. Simple precautions can help protect your kids from becoming infected. Read More Staph Infections When skin is punctured or broken for any reason, staph bacteria can enter the wound and cause an infection. But good hygiene can prevent many staph infections. Learn more. Read More Germs: Bacteria, Viruses, Fungi, and Protozoa Germs are tiny organisms that can cause disease - and they're so small that they can creep into your system without you noticing. Find out how to protect yourself. Read More Food Poisoning The germs that get into food and cause food poisoning are tiny, but can have a powerful effect on the body. Find out what to do if you get food poisoning - and how to prevent it. Read More Food Poisoning Did you ever eat something that made you feel ooky? It might have been food poisoning. Read More Diarrhea Most kids battle diarrhea from time to time, so it's important to know what to do to relieve and even prevent it. Read More The Danger of Antibiotic Overuse Taking antibiotics too often or for the wrong reason has led to a dangerous rise in bacteria that no longer respond to medicine. Find out what you can do to prevent antibiotic overuse. Read More Diarrhea Nearly everybody gets diarrhea every once in a while, and it's usually caused by gastrointestinal infections. It's nothing to be embarrassed about. Read this article to learn more. Read More Listeria Infections Listeriosis is a serious infection caused by eating contaminated food. It mostly affects pregnant women, newborns, and adults with weakened immune systems. Here's how to protect your family. Read More What Are Germs? You know they can hurt you, but what are these invisible creatures? Find out in this article for kids. Read More Abscess An abscess is a sign of an infection, usually on the skin. Find out what to do if your child develops one. Read More Food Safety for Your Family Why is food safety important? And how can you be sure your kitchen and the foods you prepare in it are safe? Read More Fighting Germs Germs are tiny organisms that can cause disease - and they're so small that they can creep into your system without you noticing. Find out how to protect yourself. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.