Infectious diseases in the workplace

Understanding the spread

In this time of the COVID-19 pandemic, everyone is being made aware of how that particular virus is spread and what its consequences are. However, infectious diseases in the workplace are nothing new, and ’s it is vitally important that employees are protected from all infectious diseases, and understand how infectious diseases are transmitted.

The world is getting smaller. People are traveling more to regions where disease and illnesses abound. At home, people go to work not realizing they are contagious, or they may feel sick and go to work anyway. Regrettably, one of the main reasons infectious diseases spread so quickly in the workplace is because some employees don’t believe they’re going to spread germs; instead they just seem to be thinking about all the work they have to do.

A scenario with COVID-19 illustrates how easy it is for diseases to travel. While traveling for work, an employee begins to feel sick and develops chest pain and a bad cough. Over the next few days, he boards a plane for home still feeling sick and coughing regularly. Upon returning home, the employee goes to work and continues life as usual until he decides to go to the doctor, only to find out he is infected with COCID-19. The implications of this scenario have become abundantly clear during the present crisis. Everyone who has come into contact with this individual is at risk for contracting the disease.
The same concerns exist in respect of other diseases such as TB, Rubella, the flu, etc.

How can we protect our employees from serious infectious diseases? First, we need to understand how infectious diseases are transmitted.

How are infectious diseases transmitted?

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1) Direct Contact Transmission

a) Person-to-person contact

Infectious diseases are commonly transmitted through direct person-to-person contact. Transmission occurs when an infected person touches or exchanges body fluids with someone else. This can happen before an infected person is aware of the illness. This is why physical distancing and avoidance of physical contact is critical in dealing with COVID-19, and indeed, many other diseases.

b) Droplet spread

The spray (respiratory secretions / splash / splatter) of droplets during coughing and sneezing can spread an infectious disease. You can even infect another person through droplets created when you speak. Large particles (droplets) can carry viruses and bacteria through the air which can then be deposited onto mucous membranes (eye, nose, mouth) of a susceptible person (e.g. via sneezing, coughing, talking). Examples of this are: COVID-19, Whooping cough, rubella, mumps, influenza, meningococcal disease.

2) Indirect Contact Transmission

Indirect contact involves touching an object or surface that has been contaminated by an infected person.


Airborne transmission occurs when infectious agents can remain suspended in air for extended periods of time. Small particles (aerosols) that are airborne, may also be deposited on mucous membranes or inhaled directly. The airborne agent may be inhaled by a susceptible person and enter the respiratory tract, where it creates the potential for infection. Examples of this are: Tuberculosis, Chickenpox, Measles.

Contaminated objects

Frequently touched surfaces (fomites) include: Door knobs, door handles, handrails, Tables, beds, chairs, Washroom surfaces, Cups, dishes, cutlery, trays, Medical instruments, Computer keyboards, mice, electronic devices with buttons, Pens, pencils, phones, office supplies, Children’s toys. An example of this is: Norovirus. You may hear norovirus illness be called “food poisoning”, “stomach flu”, or “stomach bug.” Noroviruses are the leading cause of foodborne illness. But other germs and chemicals can also cause foodborne illness. Norovirus illness is not related to the flu, which is caused by influenza virus.

Food and drinking water

Also known as Faecal-oral transmission, is usually associated with organisms that infect the digestive system. Microorganisms enter the body through ingestion of contaminated food and water. Inside the digestive system (usually within the intestines) these microorganisms multiply and are shed from the body in faeces. If proper hygienic and sanitation practices are not in place, the microorganisms in the faeces may contaminate the water supply through inadequate sewage treatment and water filtration. Fish and shellfish that swim in contaminated water may be used as food sources. If the infected individual is a waiter, cook, or food handler, then inadequate hand washing may result in food being contaminated with microorganisms. Examples of this are: Botulism, Cholera, Hepatitis A, Listeriosis, Paralytic Shellfish Poisoning, Paratyphoid Fever, Salmonellosis, Typhoid Fever

Fecal-oral transmission can be reduced by:

  • Proper storage of food at proper temperatures
  • Thorough cooking of food
  • Frequent and thorough handwashing, especially after washroom use
  • Adequate sewage treatment and water filtration/chlorination systems
  • Disinfection of frequent touch surfaces to prevent indirect contact transmission
  • Increased public awareness of proper hygiene and food handling

Vector-Borne and Zoonotic Diseases

Vector-borne and zoonotic diseases are caused by viruses, bacteria or parasites that are transmitted to humans from animals or insects. Some diseases that originate in animals must be transmitted through a “vector” in order to infect a human. Zoonotic diseases can come from a variety of sources like bacteria, viruses, parasites and fungi. Additionally, the World Health Organization states 75% of all new pathogens in the last decade are zoonotic. It is believed that the COVID-19 virus is a zoonotic disease.

Vectors are animals that are capable of transmitting diseases. Examples of vectors are flies, mites, fleas, ticks, rats, and dogs. The most common vector for disease is the mosquito. Mosquitoes transfer disease through the saliva which comes in contact with their hosts when they are withdrawing blood. Mosquitoes are vectors for Malaria, West Nile virus, Dengue fever, and Yellow fever. Other Examples of vector-borne and zoonotic diseases are: Anthrax, Avian flu, Brucellosis, Hantavirus, Histoplasmosis, Lyme disease, Plague, Psittacosis (Parrot Fever) ,Q Fever (Query fever), Rabies, Seoul Virus Infection, Tularaemia, Viral Haemorrhagic Fevers, Zika Virus. COVID-19 is not believed to be transmitted to humans by any vector other than other humans.

A large family of viruses, coronavirus is responsible for everything from the common cold to SARS (severe acute respiratory syndrome), including the newest strain #COVID-19
The coronavirus crossed species to start infecting humans causing a world pandemic in 2020. These infections affect the respiratory system with symptoms like fever and cough. Severe infections can lead to pneumonia, other complications, and even death.

There is a reason that you give your dog or cat a rabies vaccine! That’s because they can transfer rabies to you. A virus transmitted by a bite; rabies affects the nervous system. While it can be treated, once clinical symptoms appear, it’s typically fatal.

Lyme Disease
Tick bites are more than just annoying. They can end badly, especially if the tick is carrying the bacteria Borrelia burgdorferi. Transferred during the bite of a blacklegged tick, Lyme disease includes symptoms like fever, headache and fatigue. While it can be treated with antibiotics in the early stages, Lyme disease might have lasting effects.

Reptiles and baby chicks are fun to play with, but it’s important to wash your hands after. This is because they carry Salmonella bacteria. If that Salmonella gets into your system, it can cause severe gastrointestinal symptoms and fever. While this is a mild infection most of the time, it can cause severe symptoms.

Swine Flu
Pigs get the flu virus. And when they do, they can pass this flu on to humans. A common flu that passed to humans was H1N1. Passed through airborne respiratory droplets, this type of flu causes fever, cough and body aches. In certain individuals, it can lead to more serious infections. The 1918 flu pandemic was caused by the swine flu.

In addition to viruses and bacteria, parasites also transfer from animals to humans. One such parasite is giardiasis, which can be ingested through contaminated food and water. It’s excreted through faeces and can live for a long time in the soil. Dirt can then easily make it from your hands into your mouth causing giardiasis infections. Symptoms of giardiasis include diarrhoea, nausea and weight loss.

A common skin infection caused by a fungus; ringworm can be easily transferred from animals to humans. Ringworm infections can affect the feet, scalp, groin or anywhere on the body. The symptoms are a raised lesion that looks like a circular worm. Hence, that’s why the infection is named ringworm.

Vectors add an extra dimension to disease transmission. Since vectors are mobile, they increase the transmission range of a disease. Changes in vector behaviour will affect the transmission pattern of a disease. It is important to study the behaviour of the vector as well as the disease-causing microorganism in order to establish a proper method of disease prevention. In the case of malaria, insecticides were sprayed and breeding grounds for mosquitoes were eliminated in an attempt to control the spread of malaria.

Some zoonotic diseases can be transmitted directly to humans through contact with saliva, some are airborne, and others are transmitted through insect bites. Diseases can also be spread through the faeces of a vector. Microorganisms could also be located on the outside surface of a vector (such as a fly) and spread through physical contact with food, a common touch surface, or a susceptible individual.

When an employee/worker succumbs to a serious viral illness or disease, what can we do to prevent further spread?

It’s important to follow best practices, but prevention is always better than cure, so workers should be advised to take proper preventive measures. Infectious disease experts say it’s highly advisable to obtain recommended vaccinations and immunizations to help prevent illness and the spread of disease.

Other important steps to remember in reducing the spread of infectious agents:

  1. Practice proper hand hygiene! Wash hands thoroughly to prevent the spread of infection.
  2. Stay home when you are ill! Don’t put others at risk of exposure (Self isolation)
  3. Travel wisely! Don’t travel on public transportation, by rail or air when you’re ill.
  4. Don’t share items! Passing around items that have been touched by an infected person can transfer the illness.
  5. Practice respiratory hygiene! Wear a mask.
  6. Adhere to proper infection/exposure control precautions!

How to reduce the risks!

If workers are at risk for infectious disease at the workplace, employers must develop and implement an exposure control plan.
As a general rule, safe work practices everyone should follow include:

  1. Getting vaccinated! Many infectious diseases are preventable through vaccination.
  2. Wash hands frequently! Wash your hands: After touching tools or equipment used by more than yourself • After touching potentially contaminated materials or surfaces such as taps, door handles, etc. • Before eating, drinking, smoking, handling contact lenses, applying makeup, or using the toilet • Handling sharps properly • Follow manufacturer recommendations for using and disposing of sharps • Cleaning and disinfecting spills • Specific procedures are required to contain spills of bodily fluids!
  3. Use Personal Protection Equipment properly! Workers should know how to select appropriate PPE. Putting on, wearing and removal of PPE. This includes Gloves, Respirators, Face masks, Gowns, Foot covers, Eye protection etc.
  4. Practising cough etiquette! Always cough into your sleeve or a tissue instead of your hand, and wash hands after coughing.
  5. Stay home if you are sick! Workers should stay home if they are ill, especially if they are vomiting or have a fever or diarrhoea.


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