Image 1: E. Coli Bacteria
(Photo by NIAID via Wikimedia Commons)


The word “germ” refers to many different microscopic organisms such as bacteria, viruses, fungi and protozoa that can cause diseases.

In some cases, either bacteria or a virus can cause ailments such as pneumonia, meningitis, diarrhea, and ear infections. Both bacteria and viruses are too small to be seen without a microscope, but there are many differences between these two microbes.

Image 2: Fungi
(Photo by Edward Step [Public domain] via Wikimedia Commons)

Bacteria are responsible for illnesses such as anthrax, Lyme disease, strep throat, tuberculosis, urinary tract infection and tetanus. They are single-celled with the majority of them having a rigid cell wall. They can reproduce on their own and can survive in extreme heat, cold and in radioactive waste. Most are harmless and some are even helpful such as bacteria in our gut that help us digest our food. Less than 1% of bacteria cause diseases in people.

Image 3: Rumen Protozoa
(Photo by CSIRO via Wikimedia Commons)

Viruses are responsible for the common cold, flu, measles, mumps, polio, chicken pox, smallpox, cold sores and rabies. Viruses are very tiny; they are even smaller than bacteria. They cannot multiply without a host since they reproduce by infecting other cells. Many viruses cause disease and some of them attack bacteria.

Fungi are organisms such as yeast, molds and mushrooms. The most common infection from fungi is athlete’s foot. Fungal infections are rarely serious as anti-fungal drugs are available for treatment.

Protozoa are single celled organisms that cause diseases such as malaria.

How are germs transmitted?

Contact Transmission

  • Germs can spread to the hands by sneezing, coughing or rubbing the eyes and then can be transferred to other family members or friends through contact.
  • Remedy: wash your hands well; do not cough or sneeze into your hands.

  • Germs from the unclean hands of a food preparer can be passed to those who eat the food.
  • Remedy: always wash hands especially after using the washroom.

  • Germs from raw foods such as chicken can be transferred to the hands while preparing a meal. The germs can then be passed to other foods such as salad.
  • Remedy: cook the raw food to kill the germs; wash hands after handling raw foods.

  • Germs can be picked up by petting animals or touching surfaces the animals contact.
  • Remedy: wash your hands after petting animals.

Airborne Transmission

  • The common cold is spread when a virus attaches itself to droplets of moisture or to dust particles, thus allowing them to travel long distances where they can be inhaled by other people.
  • Remedy: cough into your elbow or sleeve but not your hand.

How does our body protect us from germs?

Our bodies have an immune system which works to protect the body from germs that cause infections and fights sickness that has already started. The immune system is a network of cells, tissues and organs that work together to protect the body. White blood cells (called leukocytes) are part of this system.

Image 4: 3D rendering of various types of white blood cells
(Illustration by Source: Wikimedia Commons)

White blood cells are a vital part of our immune system. They carry out various functions such as:

  • releasing enzymes to deal with infectious and allergic reactions.
  • destroying foreign microorganisms and materials.
  • remembering and recognizing previous invaders.

Leukocytes are produced in the lymphatic system, mainly in the bone marrow, but also in organs such as the thymus, the spleen and the lymph nodes.

Although the immune system is essential to help keep us healthy, in some cases it may fight good cells which is what occurs in diseases such as lupus or juvenile rheumatoid arthritis. Often, immune disorders can be treated with medicine but you can help your immune system stay healthy by washing your hands regularly, eating nutritious foods, getting enough sleep and getting plenty of exercise.


All germs can be destroyed by antibiotics.

Correction: Only bacteria can be killed by antibiotics (except for highly resistant “superbugs”). Antibiotics don’t work against viruses. Vaccines are used for viruses.

Playing in the rain can cause a cold.

Correction:Getting chilled likely has no bearing on whether or not you get a cold. Some factors that can increase susceptibility to the common cold include being stressed, smoking and spending time with other people who have colds.

Did You Know?

  • When you sneeze, germs can travel up to 160 km per hour.
  • The most common illness spread from recreational water activities is diarrhea.
  • Fungi are neither plant nor animal. They are a category (or kingdom) of their own.
  • An example of a serious case of a bacterial disease is the bubonic plague (or Black Death). During the 14th century it killed approximately 50 million people. The bubonic plague still exists today, though it is much less serious. In 2013, it killed 126 individuals.
  • Examples of serious viral infections were the “Spanish flu” epidemic of 1918-1919 that killed 20-40 million people, and the HIV/AIDS epidemic.
  • Diaper rash can be caused by a fungal infection due to dampness under the diaper. The best remedy is to expose the rash air or to change the baby’s diaper often.


Bacteria (Accessed on November 14, 2016)
Encyclopedia Britannica

Infectious Disease (Accessed on November 14, 2016)
Encyclopedia Britannica

Coughs and Sneezes (Accessed on January 16, 2017)
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