Occupational health: Biological Risks
DefinitionsDifferent kinds of biological factors are encountered in a wide range of work places. The biological agents may cause a variety of health effects in humans, such as infectious diseases, acute toxic effects, allergies and even cancer. We will tell you about different kinds of biological factors, different health effects and describe occupations where exposures to biological exposures are abundant. We will also tell you about some preventive measures, such as vaccination. Biological factor is a broad term. It includes many agents, such as:
- Bacterial endotoxins
- Allergens (high molecular weight)
- Plant fibres
- Patients suffering from a contagious disease
- Stool, blood, saliva and other body fluids from infected humans or animals
- Healthy carriers of an infectious disease, who themselves are not ill
- Work processes producing dust, droplets and aerosols containing a range of microorganisms
- Work processes where microorganisms may contaminate instruments, tools or facilities
Spreading of infectious diseases
- Person-to person contact. Spread of infectious agents by skin or mucous membrane contact, including blood or other body fluids, and transmission of infectious diseases via placenta in pregnant workers.
Examples: Skin infections due to Staphylococcus aureus, Ebola.
- Droplets spread containing infectious agents. Due to their size, these droplets travel only a short vertical distances (less than a metre) from the infected person before falling down.
Example: Rubella, COVID-19.
Biological factors can cause other negative health effects than infections. They can for instance produce toxins. Tetanus is a disease of the nervous system caused by a toxin produced by the bacterium Clostridium tetani. This bacterium is found in soil and animal faeces produces and it produces spores, which are resistant cells, able to survive in the soil for many years. The bacteria may contaminate wounds that penetrate the skin, and farmers and others who work with soil and/or animals are especially at risk. The initial wound is often quite trivial and may not even have received medical attention, but it can lead to a lethal disease such as tetanus, if treatment is not given in time. Toxins may also give rise to infection-like diseases such as gastroenteritis due to toxin-producing Escherichia coli resulting from eating raw or undercooked meat or from being in contact with farm animals. Some toxins can seriously affect the liver and cause cancer.Indirect contact
- Airborne transmission. Droplets evaporate quickly, but the microorganisms can stay airborne for a long time. Due to their tiny size, small particle aerosols can travel long distances on air currents and remain suspended in the air for minutes to hours and can infect anyone who breaths the contaminated air.
- Contaminated objects including needles, syringes and contaminated blood products, surfaces and materials.
Examples: HIV infection, hepatitis B and C due to needle stick injuries, Ebola.
- Food and drinking water.
- Animal-to-person contact. Infectious disease due to bites or scratches by an infected animal, or handling of animal waste.
Examples: Tetanus. Toxoplasmosis due to contact with cat feces.
Example: Anthrax (from sheep) in farmers and veterinarians.
- Soil, water and vegetation containing infectious organisms.
Examples: Toxoplasmosis in cat feces. Tetanus in soil. Legionella spread due to aeration of water by cooling towers.
BioaerosolsThe term bioaerosol is often used about aerosols or particulate matter of microbial, plant or animal origin. The term “organic dust” is often used synonymously. Bioaerosols may consist of different kinds of pathogenic or non-pathogenic live or dead bacteria as well as fungi, viruses, high molecular weight allergens, bacterial endotoxins, mycotoxins, peptidoglycans, β-glucans, pollen, and plant fibres. A wide range of health effects may develop due to bioaerosol exposure, including the infectious diseases described above. A number of diseases may arise from inhalating fungal spores in the course of handling decaying matter, faeces, compost or soil. Farmers, veterinarians, health care workers and biomedical workers studying infectious agents are at the highest risk for occupational infectious diseases due to bioaerosol exposure. Putting “husk material” -waste from coffee production- into bags may cause high levels of exposure to organic dust and endotoxins. This may cause asthma problems among the workers. © B.E. Moen
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Occupational Health in Developing Countries
Occupational Health in Developing Countries
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