Infectious Disease

An infectious disease is an illness caused by a microbe – an organism too small to be seen with the naked eye. Bacteria, virus, fungi and protozoa are all disease-causing microbes.

A child sneezes at schoolA colleague coughs and doesn’t cover his mouth; a student gets creative when there are no tissues to wipe her runny nose; friends share a water bottle or lip balm – when you think about it, germs can pop up anywhere ­– and they are all looking for you!

While having contact with some germs is a good thing – it helps to build immunity and resistance to getting sick – it’s always best to take precautions against germs in a school setting to help prevent the spread of infectious diseases.

Germs can be found in every corner of the school environment, making it important not only to ensure proper personal hygiene, but also to consistently clean for health. NEA Healthy Futures offers a number of resources that address both specific infectious diseases and methods to prevent the spread of disease.

Types of Infectious Disease

woman-sneezing-sickMost infectious disease will be caused by one of four types of germs:

  • Bacteria – single-celled organisms that reproduce themselves, by themselves.
  • Virus – microorganisms that cannot reproduce themselves; they take over the cells they infect in order to reproduce and spread.
  • Fungi – look like plants, but live off of animals, people and plants (examples are mushrooms and yeast).
  • Protozoa – small parasites that live in the water and live off of other organisms, such as humans (examples include malaria and giardia).

There are various types of infectious disease. Some of the most common in the school environment include:

  • Influenza (the flu)
  • MRSA
  • Norovirus
  • Bloodborne pathogens


feverInfluenza (the flu) is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness, and at times can lead to death. Some people, such as older people, young children and people with certain health conditions, are at high risk for serious flu complications. The flu is usually more severe than a cold and includes symptoms of fever, body aches, extreme tiredness and dry cough. It is mostly spread in respiratory droplets of coughs and sneezes.

For further information on the flu, please visit Centers for Disease Control and Prevention’s Flu Information.


Methicillin-resistant Staphylococcus aureus, or MRSA, refers to a type of staph infection that is resistant to a type of antibiotic methicillin and other types of antibiotics.

Staph infections, including MRSA, occur most frequently among persons in hospitals and healthcare facilities (such as nursing homes and dialysis centers) who have weakened immune systems. These healthcare-associated staph infections include surgical wound infections, urinary tract infections, bloodstream infections and pneumonia.

Staph or MRSA infections in the community are usually manifested as skin infections that look like pimples or boils and occur in otherwise healthy people. Learn more from the CDC’s information on MRSA in the workplace.


stomach-bug-book-page-001Noroviruses are a group of viruses that cause acute gastroenteritis – or, the dreaded stomach bug. The most common symptoms are diarrhea, vomiting and stomach pain. Norovirus is very contagious, and can be serious, especially for young children or older adults. A person usually develops symptoms 12 to 48 hours after being exposed to the virus, and most people with get better within 1 to 3 days, according to the CDC.

For additional information, please read NEA Healthy Futures’ Stomach Bug Book or visit the CDC’s website. (The Stomach Bug Book is also available in Spanish).

Bloodborne Pathogens

Viruses carried by blood are known as bloodborne pathogens (disease producing microorganisms found in the blood). Many school personnel come in contact with blood and other bodily fluids when at work — whether in the classroom, on the playground, in the cafeteria, on the playing field or on the school bus. That is why it is important for all school employees to understand the danger of exposure to infections and ways to minimize their risk.

redbook_standard_full_1Bloodborne diseases include:

For more detailed information on bloodborne diseases and their prevention, including in schools, please review our Red Book. Exposure to Blood on the Job: What School Employees Need to Know.

For additional information on bloodborne pathogens, please visit NIH’s AIDS Information site and the U.S. Department of Labor Occupational Safety and Health Administration.

To learn about ways to prevent the contraction and spread of infectious diseases, please visit our infectious disease prevention page.