Microbiological Risk In Industrial Hygiene

Microbiological hazards are often encountered in the workplace and can represent a genuine occupational exposure risk. Microorganisms are ubiquitous in the environment and in certain situation their concentration can be greatly amplified in human created environments.

Industrial workers can be potentially exposed to microorganisms which can cause diseases in otherwise healthy individuals. Parasitic or infectious diseases are caused by organisms such as bacteria, viruses, fungi or protozoic parasites. In addition to directly caused diseases many microbes can stimulate allergic reactions in sensitive individuals. These immunological responses are defined as conditions caused by hypersensitivity of the immune system to typically harmless substances (Enzymes, Pollen, Endotoxins, Fungal Glucans, Mycotoxins etc.)

Microbiological exposures are modelled differently to chemical exposures and the dose/response relationships are much more complex and highly dependent on the personal health of the exposed individuals. The situation is further complicated by the fact that a relatively small concentration of pathogen can lead to infection, although the higher the exposure the higher is the likelihood of infection. The concentration of microbiological agents in the environment can be highly localized, highly concentrated and can increase in time if the microenvironmental conditions are conducive to microbial growth.

Exposure limit do exist for some substances of biological origin such as some of the microbial VOC (Carbon dioxide, methanol, acetaldehyde) but limits for airborne microorganisms in industrial environment do not exist. However, there are some limits in place for specialised situations such as hospital operating theaters or limits set up by the environmental agency for assessment of bioaerosols around composting sites. Limits are also sets for some infections agents such as legionella, microorganisms in water, foodstuff and such but these are outside of the realm of industrial hygiene.

Below we have provided and overview of the most common infections biological agents which can be encountered in the industrial environment.

There are many viral agents in the natural environment that can be a causative agent of a disease. Most at risk are usually workers which can come across the reservoir of viruses. From the rerspective of occupational hygiene the most notable agent is Hepatitis:

Disease	Organism	Workers at greatest risk	Route of exposure
Hepatitis	Hepatitis A, B, C , E G virus	Sewage workers	Inoculation, fecal-oral

Bacterial agents are ubiquitous in the environment, but certain work environments can provide very favorable conditions for bacterial growth.

Disease	Organism	Workers at greatest risk	Route of exposure
Actinobacter neumonia	Actinobacter calcoaceticus	Foundry workers, machinists	Inhalation
Anthrax	Bacillus anthracis	Abattoir workers, restoration and construction workers	Dermal/ Inhalation
Ascariacis	Ascaris lumbricoides	Sewage workers	Feacal, ingestions, foodborne
Helicobacter	Helicobacter piroly	Sewage workers	Ingestion
Legionnaire’s disease	Legionella pneumophillia, Legionella sp.	Manufacturing, power plant, water vessels, water cooling	Inhalation
Leptospirosis	Leptospira interoggans	Abattoir workers, sewage workers	Inoculation, bite
Silicotuberculosis	Mycobacterium tuberculosis	Mine workers, sand blasters, construction workers, foundry workers	Inhalation
Streptococcal pneumonia	Streptococcus zooepidemicus	Dairy farmers	Ingestion of contaminated milk
Tetanus	Clostridium tetani	Farmers, Construction workers, composting workers, waste recycling	Inoculation

Fungal pathogens can pose a risk to human health in a number of ways. Some fungi produce toxins that can cause illness or disease when ingested or inhaled. For example, the fungus Aspergillus produces a toxin called aflatoxin, which can cause a range of health effects including cancer, liver damage, and immune system suppression. Other fungi can cause infections in the body, either externally on the skin or internally in organs such as the lungs or sinuses. These infections can range from mild and easily treatable to severe and potentially life-threatening.

 

Disease	Organism	Workers at greatest risk	Route of exposure
Adiaspiromycosis	Chrysosporium parvum	Grain handlers, warehouse workers	Inhalation
Aspergillosis	Aspergillus flavus	Compost workers, grain handlers, construction workers	Inhalation
Coccidioidomycosis	Coccidioides immitis	Construction workers, dry sandy soils	Inhalation
Cryptococcosis	Cryptococcus neoformans	Poultry breeders	Inhalation of bat and bird droppings
Histoplasma	Histoplasma capsulatum	Wet soils enriched with bird droppings, disturbance required, (endemic to misssisipy valley), ploughing fields, digging, construction work and gardening can release fungal spores into the air from the soil.	Inhalation
Blastomyces	Blastomyces dermatitidis	Wet soils , decomposing matter, leaves	Inhalation, very rare in UK

Protozoic pathogens are tiny single-celled organisms that can cause illness or disease in humans. Some protozoa are transmitted through contaminated food or water, while others are transmitted through insect vectors such as mosquitoes or ticks.

Protozoal infections can cause a range of health problems, including diarrhea, abdominal pain, and malnutrition. Some protozoa, such as Plasmodium, which is the cause of malaria, can be life-threatening if left untreated. Other protozoa, such as Giardia and Cryptosporidium, can cause gastrointestinal illness, which can lead to dehydration and malnutrition.

 

Disease	Organism	Workers at greatest risk	Route of exposure
Cryptosporidiosis	Cryptosporium parvum	Sewage workers – causes diarrhea	Feacal-oral