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Main risks of infection

On this page, you will find more information on the main risks of infection in the work environment, when the existence of infectious agents is not intentional. However, not all microorganisms that exist in the work environment are harmful to your health. But those microorganisms who are infectious agents may cause diseases in humans, regardless of whether they exist in the work environment or in society as a whole.

Infectious diseases caused by infectious agents are likely the first thing people in general think of when discussing microorganisms and the risks they involve. Mostly, bacteria or viruses are the cause of infectious diseases. The harmfulness of an infectious agent depends, inter alia, on how it is transmitted, its capability to cause infection, and ability to survive inside and outside the human body. Becoming infected may have various serious consequences depending on the duration of the disease, treatment opportunities, and whether it may do permanent damage or lead to complications.

Definition of infectious agents

According to the regulations on risks of infection (AFS 2018:4), infectious agents are microorganisms, prions, and human internal parasites that may cause infections in humans.

Risks of infection (AFS 2018:4), provisions (SWE)

Infectious diseases in the work environment

Here you will find information on how you may become infected and some of the infectious agents that occur in the work environment.

If you wish to learn more about single infectious agents and the diseases they cause, this information is available from the Public Health Agency of Sweden.

The Public Health Agency of Sweden’s website, opens in a new window

Which infectious agents you risk being infected with depends on how they are transmitted and when and where they occur.

The transmission route describes how an infectious agent is transmitted. One and the same infectious agent may have different transmission routes. It is important to know which transmission routes an infectious agent may take to determine which protective measures are needed in a business. Therefore, we describe what we mean by different transmission routes below.

Direct and indirect contact infection means contact between humans or with objects

Contact infection means that the infection is directly transmitted through, for example, handshakes or close-contact care of sick patients. Infection may also spread indirectly through contact with objects that sick individuals or asymptomatic disease carriers have touched. Antibiotic-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) and cold viruses often spread via contact infection.

Droplet infection and indirect droplet infection may occur when coughing

If anyone with a respiratory infection coughs, this forms a cloud of droplets that contains infectious agents. The droplets may reach 1–2 metres. Individuals nearby may inhale the droplets or end up with the droplets in mucous membranes, such as the eye mucosa, and become infected. Droplet infection is a common transmission route for respiratory infections.

When the droplets from coughing or vomiting have fallen onto surfaces and objects in the surroundings, the infectious agents may be transmitted via contact infection. Indirect droplet infection is a common transmission route for both respiratory infections and winter vomiting disease.

Airborne infection and aerosols

The droplets that transport infectious agents in cases of airborne infection are smaller than those in droplet infection and may remain in the air longer. Such droplets may form when disease carriers exhale or when the droplets coming from someone coughing or sneezing have dried into a smaller size. If there are enough little droplets in the air, anyone who breathes them in may become infected. This is called an airborne infection. Risk of airborne infection primarily exists indoors where there is a low air change rate. Outside, droplets containing infectious agents are easily blown away or diluted. Example of infectious agents that may be transmitted via airborne infection include the measles virus, influenza virus, and tuberculosis bacteria.

Every day, humans shed massive amounts of tiny skin particles. Many of these carry bacteria. The particles easily become airborne, and you might inhale them. Skin particles from patients with wounds or skin infections may contain bacteria and cause infection or nasopharyngeal carriage of bacteria if the particles are inhaled. The particles may also end up on surfaces, and infectious agents may then be transmitted via contact infection. Examples of bacteria that may spread this way include group A streptococcus (GAS) and antibiotic-resistant bacteria such as MRSA.

Certain microorganisms survive well in dry environments and may be transmitted through inhaling dust. Examples include Puumala orthohantavirus, which leads to vole fever (nephropathia epidemica), and the bacterium Francisella tularensis, which causes rabbit fever (tularemia). Both these infectious agents may occur in dust contaminated with urine or faeces from rodents. Another infectious agent that spreads via airborne dust is Chlamydophila psittaci, which may occur in bird faeces and causes psittacosis (parrot fever or ornithosis) in humans.


Aerosols are small particles finely dispersed in a gas, e.g. air. The particles may be solid or liquid. The aerosol includes both the gas and the particles. Typical examples of aerosols include smoke, fog, and air pollution. Both the droplets containing infectious agents that may cause droplet infection and those that may carry infectious agents in cases of airborne infection may be included in the definition of an aerosol. Finely dispersed dust particles and skin flakes carrying infectious agents may also be included in an aerosol. The upper limit for particle sizes occurring in aerosols is approximately 0.1 mm. 

Waterborne infection may be caused by bacteria, viruses, and parasites

You can get sick from ingesting unclean water containing infectious agents. Infectious agents from the human intestine may occur in sewage water, sludge, and latrine. These may be bacteria, viruses, and parasites causing diarrhoea or other diseases such as tetanus and hepatitis.

In cases where employees become infected from waterborne infectious agents, this is usually due to inhaling aerosols of the contaminated water. Aerosols with infectious agents may occur when contaminated water is stirred quickly or air bubbles form in the water.

Legionella bacteria, which causes Pontiac fever and Legionnaires' disease, grows best between 18°C and 45°C. They may occur in common water pipes, climate control systems, showers, and whirlpool baths. The only way to get sick is by inhaling aerosols with Legionella bacteria. The bacterium is quite common, and it appears to be mainly immunocompromised individuals who contract Pontiac fever and Legionnaires' disease.

Blood-borne infection may occur in various types of bodily fluids

Blood-borne infectious agents do not only occur in blood, but may also exist in other bodily fluids, especially if they include traces of blood. In cases of blood-borne infection, infectious blood or other bodily fluids must reach the recipient’s bloodstream to cause infection. You may contract a blood-borne infection if you puncture yourself on hypodermic needles or other sharp instruments that have been used on infected individuals. Examples of blood-borne infectious agents include hepatitis B, hepatitis C, and human immunodeficiency virus (HIV).

There are many different sectors where employees may risk coming into contact with blood and other bodily fluids. Examples of such activities include healthcare, social care, childcare, police, care of deceased persons, as well as tattoo artists and beauty care.

Vector-borne infection causes Lyme disease and TBE

Infectious diseases transmitted by insects or arachnids are called vector-borne infection. The infectious agent often exists inside the vector (the insect or arachnid) and is transmitted through bites. In Sweden, Lyme disease (Borrelia) and Tick-Borne Encephalitis (TBE) spread this way. The bacterium Francisella tularensis, which causes rabbit fever, may be transmitted in various ways, such as through mosquito bites and other insect bites. Mosquitoes also spread the viral disease Ockelbo disease (Sweden) (also known as Pogosta disease (Finland), and Karelian fever (Russia)).

The various vector-borne infectious agents do not occur nation-wide. For example, it is more common for ticks to carry the TBE virus in certain areas than in other areas. You can contact the local centre for infectious disease control for information on whether there is any active vector-born infection.

Known examples of diseases transmitted by mosquitoes abroad include malaria, dengue fever, West Nile fever, and Yellow Fever.

Zoonoses mean infection between animals and humans

Zoonoses are infectious agents that may be transmitted between humans and animals and cause diseases. Zoonotic agents may be transferred between animals and humans either through direct contact or indirectly via foodstuffs, water, and the environment, or by vectors such as mosquitoes and ticks. For those who interact with animals in their line of work, it is important to know that animals may be carrying agents that may cause diseases in humans even if the animals themselves are not sick.

A few examples of zoonoses include EHEC (verotoxigenic Escherichia coli), salmonella, or brucellosis (also called Malta fever or undulant fever), which may be transmitted by farm animals; salmonella, Campylobacter enteritis, and parrot fever (psittacosis), which may be transmitted by birds; and vole fever (Puumala orthohantavirus) or rabbit fever (Francisella tularensis) transmitted by wild rodents; and other various vector-borne diseases.

Sharps injuries

If you are using a sharp object on a human or an animal and accidentally puncture or cut yourself, there is a risk of transmitting a blood-borne infection. Examples of sharp objects include hypodermic needles, lancets, and scalpels. The risk of sharps injuries increases if you do not have enough training on how to use the sharp objects or if you are using non-puncture-proof products.

These are some examples of situations where there is a risk of sharps injuries with the risk of transferring blood-borne infection:

  • When performing blood tests or treatment where you administer an injection (in the healthcare sector)
  • When performing blood tests or treatment where you administer an injection to animals (in the veterinary sector)
  • When cleaning, where the used sharp object is hidden among bedclothes, laundry, or similar
  • In cases of improper waste disposal of used sharp objects
  • In laboratories where patient samples are analysed for diagnostic purposes, such as in biological chemistry laboratories
  • When treating care users within the social care sector, for example helping a user with diabetes with insulin injection
  • When taking someone into police custody and performing searches of persons
  • When cleaning public spaces or outdoor parks where sharp objects may be hidden.

Antibiotic-resistant bacteria are difficult to combat

Antibiotics are pharmaceuticals that may be used to effectively treat various bacterial diseases. There are many different types of bacteria, and there are several types of antibiotics that prevent bacterial growth in various ways. Certain antibiotics only affect some of these bacteria, while others affect several. In some cases, the bacteria have become resistant to one or several types of antibiotics – in other words, they are antibiotic-resistant. An antibiotic-resistant bacterium is more difficult to combat, as it survives a treatment that otherwise would have been effective. The antibiotic-resistance may spread between bacteria. Today, we are seeing a clear increase of antibiotic-resistant bacteria, both nationally but mainly in the world around us. It is important to counteract the spread of antibiotic-resistant bacteria in order to keep antibiotics as an effective pharmaceutical for treatment of bacterial diseases, which may be serious or life-threatening.

More information on antibiotic-resistance is available from the Public Health Agency of Sweden.

The Public Health Agency of Sweden’s website, opens in a new window

MRSA – golden staph

So-called golden staph (Staphylococcus aureus) is a common bacterium in our surroundings and on our bodies. Staphylococci can, for example, cause infections in wounds. Such infections can usually be treated with antibiotics. But certain types of staphylococci may be resistant to antibiotics. This makes these infections difficult to treat and they may cause serious illnesses in vulnerable individuals. Methicillin-resistant Staphylococcus aureus are called MRSA and are easily spread within healthcare and social care.

MRSA is also an occupational risk. Personnel, primarily within the healthcare and social care sector, may become infected with MRSA and fall ill themselves, and become bacterial carriers. If you become a bacterial carrier, this may mean that you cannot continue performing certain services, for example caring for premature babies on neonatal wards. Certain individuals are at greater risk of becoming MRSA carriers, for example if you have wounds or eczema on the skin.

Variations of MRSA may be found in pets and farm animals. It is important for people who work with animals, e.g. veterinarians, paraveterinary workers, or farm workers, to be aware of this.

Resistant tuberculosis bacteria are highly resistant

Tuberculosis is caused by bacteria (Mycobacterium tuberculosis), which may be transmitted from human to human via expectoration. Tuberculosis is not entirely easy to cure. Effective antibiotics usually have severe side effects. In recent years, tuberculosis has become more common, and there are now several variations that are resistant to various types of antibiotics. The problem with antibiotic-resistant tuberculosis bacteria is that the antibiotics left to choose from are not always as effective as the ones primarily used. These antibiotics may also result in even more severe side effects in certain cases. There are also multidrug-resistant tuberculosis bacteria – meaning they are resistant to several types of antibiotics.

Examples of risks of infection in various work environments

There are many different infectious agents and many different ways in which infectious agents may be transferred to humans in the work environment. These are a few examples of work environments and infectious agents that may occur in the workplace.

More information on various infectious agents and the diseases they may lead to is available from the Public Health Agency of Sweden.

The Public Health Agency of Sweden’s website, opens in a new window

Epidemic diseases may affect various workplaces

When society faces epidemics, especially during the winter months, viral diseases such as the winter vomiting disease and influenza may hit several workplaces. This may affect the work environment in several ways. The activities themselves may suffer when many employees are absent at the same time during a short period of time, meaning an increased workload for the remaining staff. Ongoing epidemics in society means higher risks of infection, above all to staff within care activities such as pre-schools or emergency care centres.

Legionella likes water installations

Legionella bacteria thrives in stagnant water, for example in regular water pipes, climate control systems, showers, and whirlpool baths. The bacterium may cause Pontiac fever or the more serious Legionnaires' disease. It grows best between 18°C and 45°C. You may become infected by inhaling contaminated water in droplet form. This disease is not transmissible between humans.

There are cases where people have fallen ill from Legionella bacteria after working in paper mills and with plumbing. Outbreaks of legionella have also occurred via air humidifiers in various environments.

Infectious diseases exist in emergency wards, in ambulance services, and similar

Paramedics and workers in emergency wards, infection wards, and emergency clinics (Sw. lättakuter) risk exposure to many types of infectious agents. These are services where you may need to make quick decisions to help a severely ill patient. Some infectious agents vary over the year, for example winter vomiting disease and influenza. Other infectious agents may occur at any time, for example blood-borne infectious agents. In those situations, it is important to remember the safety of the staff, especially when they are at risk of coming into contact with blood, respiratory droplets, or expectoration.

In these services, there is also an increased risk of coming into contact with unforeseen infectious agents, where some may cause serious diseases such as tuberculosis.

Sharps injuries in medical care and dental care may result in onward transmission

When working with sharp objects, for example drawing blood or administering insulin to a patient, you may suffer a needle injury. If the patient is carrying a blood-borne infection, such as hepatitis C or HIV, there is a risk of onward transmission. The wound created by a sharps injury may also become infected by bacteria.

Zoonoses when working with animals

Working in animal healthcare or similar services may entail risks of transmission of infectious agents from the animals you encounter. Just as when caring for humans, it is important to remember that even asymptomatic animals may carry infectious agents, such as MRSA.

Handling of samples in laboratories may pose risk of infection

Handling samples from humans or animals may always pose a risk of infection. Regardless of whether you are performing chemical or microbiological examinations of such a sample, there may be a risk of infection.

MRSA within social care  

In workplaces providing social care, such as home help services, residential care, or pre-schools, where you work in close proximity to other people, there is a higher risk of infection. In recent years, cross-infection with antibiotic-resistant bacteria, mainly MRSA, has become more and more common. You do not always know whether a care user is carrying an infection.

Infection from dust within farming and agriculture

In farming, there is a risk of infections spreading from animals, so-called zoonoses. The infectious diseases may come from the farmers’ own animals, but also from vermin such as voles, mice, or birds. Infectious agents may exist in and spread via dust or bird droppings. If you work out of doors, for example in forestry, there is a risk of being infected with diseases via ticks or mosquitoes, so-called vector-borne infection.

Gastrointestinal infections may occur in sewage works

Sewage water, sludge, and latrine always contain infectious agents. There is a particular risk of gastrointestinal infections caused by bacteria, viruses, or parasites, but also other diseases such as hepatitis or tetanus. The greatest risk of infection comes from splashing in pools or direct contact with the content of, for example, sewer pipes. There are also other microbiological risks tied to sewage works.

Risk of infection when exercising official authority that entails close contact with people

There are many different services in society where you have close contact with people. The Swedish Prison and Probation Service and the Swedish Police Authority are examples of such services. An individual in custody may have an infectious disease or carry used sharp objects. This puts the employee at risk of becoming infected with diseases such as hepatitis C or tuberculosis.

Sharps injuries from cleaning and waste collection

In public spaces such as parks, toilets, and trains, there may be sharp objects. They are often concealed and pose a risk when cleaning these spaces. If you accidentally puncture or cut yourself on such an object, there may be a risk of onward transmission of blood-borne infections or bacteria.

Beauty care and foot care

When performing certain treatments, such as pedicures or manicures, in a beauty parlour, there may be a risk of coming into contact with infectious diseases. This may be bacteria on the skin or infectious agents in blood or other bodily fluids.

If you perform treatments that entail puncturing the skin, such as piercing, it is extra important to consider risks of infection. Many individuals may carry infectious agents without knowing it and risk spreading infectious diseases.

Last updated 2020-06-24