Germs are tiny living organisms that are too small to see with the naked eye. They are everywhere — on surfaces, in the air, in water, and even inside your own body. Most germs are harmless, but some can cause illness ranging from a mild cold to a serious infection. This article explains what germs are, how they spread, and what you can do to protect your health and your family’s.

What Are Germs?

The word germs is a general term for microscopic organisms, also called microorganisms. Scientists group germs into four main types: bacteria, viruses, fungi, and protozoa. Each type behaves differently in the body and responds to different treatments.

Not all germs are harmful. In fact, your body contains trillions of beneficial microorganisms that help you digest food, fight off disease, and stay healthy. However, when harmful germs enter your body, your immune system works hard to destroy them.

Understanding germs is an important part of everyday health. Health Canada provides guidance on infection prevention for Canadians of all ages.

The Four Main Types of Germs

Bacteria

Bacteria are single-celled organisms that can survive on their own. They reproduce quickly and can be found almost everywhere on Earth. Most bacteria are harmless or even helpful — for example, the bacteria in your gut help break down food.

However, some bacteria cause infections. Common bacterial infections include strep throat, urinary tract infections, and some types of pneumonia. These infections are usually treated with antibiotics. It is important to take the full course of antibiotics your doctor prescribes, even if you feel better early.

Viruses

Viruses are even smaller than bacteria. Unlike bacteria, viruses cannot survive on their own — they need a living host, like a human cell, to reproduce. Once inside your body, a virus takes over your cells and makes copies of itself.

Common viral infections include the flu, the common cold, COVID-19, and chickenpox. Antibiotics do not work against viruses. Instead, your immune system usually fights them off, sometimes with the help of antiviral medications or vaccines.

Fungi

Fungi are organisms like mould, mildew, and yeast. Most fungi are not harmful to healthy people. However, they can cause infections in people with weakened immune systems or in warm, moist areas of the body.

Common fungal infections include athlete’s foot, ringworm, and yeast infections. These are usually treated with antifungal creams or medications available at your local pharmacy.

Protozoa

Protozoa are single-celled organisms that are slightly more complex than bacteria. They are often spread through contaminated water or food. In Canada, the most common protozoal infection is giardia, which causes digestive problems.

Travellers visiting countries with poor water sanitation are at higher risk. Therefore, it is wise to drink bottled or boiled water when travelling abroad.

How Germs Spread

Germs travel from person to person and from surfaces to people in several ways. Knowing how they spread helps you take steps to protect yourself and your loved ones.

Here are the most common ways germs spread:

Direct contact: Touching an infected person, such as shaking hands or hugging.
Droplets: Breathing in tiny droplets released when someone coughs, sneezes, or talks.
Contaminated surfaces: Touching a surface that has germs on it, then touching your face.
Contaminated food or water: Eating or drinking something that contains harmful organisms.
Animal contact: Being bitten or scratched by an infected animal or insect.

In Canada, respiratory illnesses spread most easily during the fall and winter months. This is partly because people spend more time indoors in close contact with others. As a result, cold and flu season peaks between November and March each year.

How Your Body Fights Germs

Your body has a remarkable built-in defence system called the immune system. It works around the clock to identify and destroy harmful germs before they can cause serious illness.

Your first line of defence includes your skin, which acts as a physical barrier. Your saliva, mucus, and tears also contain substances that kill many types of germs. Furthermore, the tiny hairs in your nose and airways trap particles before they reach your lungs.

When germs do get inside your body, your immune system sends white blood cells to attack them. This is what causes symptoms like fever, swelling, and fatigue — your body is actively fighting back. In most cases, a healthy immune system clears the infection within days.

Vaccines are one of the most powerful tools we have to help the immune system. They train your body to recognize specific germs so it can respond faster if you are ever exposed. The World Health Organization explains how vaccines work and why they matter for global health.

How to Protect Yourself from Harmful Germs

The good news is that you can take simple, everyday steps to reduce your risk of getting sick. These habits are especially important during cold and flu season, and in crowded public spaces like schools, transit, and shopping centres.

Wash Your Hands Regularly

Handwashing is one of the most effective ways to stop germs from spreading. Use soap and warm water, and scrub for at least 20 seconds. Do this before eating, after using the washroom, after coughing or sneezing, and after touching shared surfaces.

When soap and water are not available, use an alcohol-based hand sanitiser with at least 60% alcohol. However, handwashing is always the preferred method when possible.

Keep Your Vaccinations Up to Date

Canada’s publicly funded immunisation programmes protect Canadians from many serious diseases caused by germs. Most provinces and territories offer free flu shots, routine childhood vaccines, and COVID-19 boosters through public health programmes.

Talk to your family doctor or visit a walk-in clinic to find out which vaccines are recommended for your age group. Staying up to date is one of the simplest things you can do for your long-term health.

Avoid Touching Your Face

Germs on your hands can enter your body through your eyes, nose, and mouth. Try to avoid touching your face, especially in public places. This is easier said than done, but even small improvements make a real difference.

Clean and Disinfect Shared Surfaces

High-touch surfaces like doorknobs, light switches, phones, and countertops can harbour germs for hours or even days. Clean these surfaces regularly, especially when someone in your household is sick.

Practise Proper Food Safety

Many harmful germs spread through food. Always wash fruits and vegetables, cook meat to the proper internal temperature, and refrigerate leftovers promptly. In addition, keep raw meat separate from ready-to-eat foods to avoid cross-contamination.

Support Your Immune System

A healthy lifestyle helps your body fight off germs more effectively. Aim for regular physical activity, a balanced diet rich in fibre and nutrients, enough sleep, and stress management. These habits strengthen your immune response over time.

Mayo Clinic’s guide to infectious diseases offers further reading on how infections develop and how to prevent them.

When to See a Doctor

Most germ-related illnesses are mild and clear up on their own within a week. However, some symptoms signal that you need medical attention right away.

See your family doctor or visit a walk-in clinic if you experience any of the following:

A fever above 39°C (102°F) that does not come down with medication
Symptoms that get worse after a few days instead of improving
Difficulty breathing or chest pain
Signs of a skin infection, such as redness, warmth, swelling, or pus
Severe vomiting or diarrhoea lasting more than 24 hours
A stiff neck combined with a severe headache and fever
Confusion, difficulty staying awake, or unusual behaviour

If you are unsure whether your symptoms need medical care, you can call your provincial health line. For example, Ontario residents can call Telehealth Ontario at 1-866-797-0000, and most other provinces offer similar nurse-staffed phone lines available 24 hours a day.

Always consult a qualified healthcare provider before starting any treatment. This article is for general information only and does not replace professional medical advice.

Frequently Asked Questions About Germs

What is the difference between germs and bacteria?

Germs is a broad, everyday term that refers to any microscopic organism that can cause illness. Bacteria are just one specific type of germ. Other types of germs include viruses, fungi, and protozoa, each of which affects the body differently.

Can germs live on surfaces for a long time?

Yes, some germs can survive on hard surfaces for hours or even several days, depending on the type and the conditions. For example, the flu virus can live on surfaces for up to 24 hours. Regular cleaning and disinfecting of high-touch surfaces helps reduce this risk significantly.

Are all germs harmful to humans?

No, the vast majority of germs are not harmful and many are actually beneficial. Your digestive system depends on trillions of helpful bacteria to function properly. Only a small fraction of all known germs cause disease in humans.

How do germs make you feel sick?

When harmful germs enter your body, they multiply and damage your cells or produce toxins that disrupt normal body functions. Your immune system then kicks in to fight the infection, and symptoms like fever, fatigue, and soreness are often signs of this immune response at work. In most cases, your body clears the germs and you recover fully.

What is the best way to stop germs from spreading?

The single most effective habit is regular, thorough handwashing with soap and water for at least 20 seconds. Staying up to date on vaccines also plays a major role in preventing the spread of many dangerous germs. Avoiding close contact with sick individuals and cleaning shared surfaces regularly also help.

You should visit a walk-in clinic or your family doctor if your symptoms are severe, worsening after a few days, or include a high fever, difficulty breathing, or signs of infection. When in doubt, it is always better to seek medical advice than to wait. Most provincial health lines also offer free nurse advice by phone around the clock.

Key Takeaways

Germs are microscopic organisms that include bacteria, viruses, fungi, and protozoa.
Most germs are harmless or beneficial. Only a small number cause illness in humans.
Germs spread through direct contact, droplets, contaminated surfaces, and food or water.
Your immune system is your body’s natural defence. Vaccines, handwashing, and a healthy lifestyle all support it.
Simple habits — like washing your hands regularly and keeping vaccinations current — are your best protection against harmful germs.
See your family doctor or visit a walk-in clinic if your symptoms are severe or do not improve after a few days.
Always speak with a healthcare professional for personalised medical advice.