Biological hazards (biohazards) present the Occupational Health and Safety (OHS) professional with complex challenges. Many and varied biohazards may result from workplace exposure to organisms, or substances produced by organisms, that threaten human health. Although workers in health and community care, and agricultural and fishing occupations are at particular risk of exposure to hazardous biological agents, all workplaces harbour the potential for various forms of biohazard exposure, including person-to-person transmission of infectious disease. While prevention and management of biohazards is often the responsibility of occupational or public health personnel, the generalist OHS professional should have an understanding of biohazards and their mechanisms of action, and the importance of vigilance and standard control measures. Armed with this knowledge, the generalist OHS professional can work with occupational health personnel to develop and implement bio hazard prevention and mitigation strategies.

1. Institute of Health
faculty of Public health
Schools of Environmental health
Seminar presentation on
Occupational Biohazards
By : Mohammedgezali I.
Jimma, Ethiopia
May,2019

2. OUT LINES
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 Introduction
 Determinants of infections
 Chain of disease occurrence
 Some occupational infection
 Blood born pathogens
 Air born pathogens
 Food born pathogens
 Water born pathogens
 Evaluation and risk assessments of
exposure
 Control measures

3. Biological Hazards
 biohazards encompass biological substances including
– microorganisms,
– Plants toxins , or invertebrate animals
– medical waste, or
– samples of body tissues or
– fluids from a biological source,
– depending on the nature of the occupation, workers also may be at risk of
harm from vertebrates
 biological agents capable of creating a hazard to human health

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Biological hazards
Biological agents are classified into risk groups, according to
their level of risk of infection:
 group 1 = unlikely to cause human disease;
 group 2 = can cause human disease and might be a hazard to
workers; it is unlikely to spread to the community; there is usually
effective prophylaxis or treatment available;
 group 3 = can cause severe human disease and present a serious
hazard to workers; it may present a risk of spreading to the
community, but there is usually effective prophylaxis or treatment
available;
 group 4 = causes severe human disease and is a serious hazard to
workers; it may present a high risk of spreading to the community;
there is usually no effective prophylaxis or treatment available.

5. Classification of Biohazards
 Microorganisms
– Examples: viruses,
bacteria, fungi, protozoa,
algae
– Reactions: infection,
exposure, allergic
reactions
 Arthropods
– Examples: crustaceans,
arachnids, insects
– Reactions: skin
inflammation, allergic
reactions, systemic
intoxication, transmission
of infectious agents
 Allergens
– Examples: from higher
plants
– Reactions: Dermatitis,
rhinitis, asthma
 Protein Allergens
– Examples: vertebrate
animals (urine, feces,
hair, saliva, dander)
– Reactions: allergic
reactions
 Parasites
– Examples: ticks,
hookworms, pinworms
– Reactions: skin reaction,
inflammatory response,
allergic reaction

6. Factors affecting infection and exposure
 Modes of transmission :is vital to breaking the infection cycle.
Contact (direct/indirect, zoonotic); vector-borne, airborne
 Routes of entry
 Infectious dose (infective dose)
Number of microorganism
 Viability and virulence of agent
Viability - Ability to replicate
Virulence – Ability to cause disease
 Host susceptibility
Skin disorders, immune system, vaccination allergy, work
practices

7. For illness to occur…..
 The agent must be pathogenic.
 There must be a reservoir of
sufficient number.
 The agent must escape the reservoir.
 The organism must be able to move
through the environment.
 There must be a portal of entry for
the host.
 The host must be susceptible to the
agent.

8. Who are at risk of biological hazards
 Employees could come into contact with infectious as a result of
the kind of work they do
 Employees who are most at risk from biological hazards include
 health care workers.
 animal breeding facilities and veterinarians
 Agriculture and food industry workers
 municipal sanitation participants
 sewage system operators .
 animal and plant products handlers
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9. Blood borne Pathogens
 Pathogenic organisms that are present in human blood,
and Can cause disease in humans
 Includes but not limited to:
– Hepatitis A virus (HAV)
– Hepatitis B virus (HBV)
– Hepatitis C virus (HCV)
– Human immunodeficiency virus (HIV)
Some occupational infections

10. Employees Potentially At Risk
 Physicians and surgeons
 Nurses
 Phlebotomists
 Medical examiners
 Dentists and dental workers
 Some laundry and
housekeeping employees
 Clinical/diagnostic
laboratory workers
 Medical technologists
 Nursing home personnel
 Dialysis personnel
 Food handlers
 Sewage workers

11. Airborne pathogen
 are pathogenic microbes small enough to be
discharged from an infected person via
coughing, sneezing, laughing and close
personal contact or aerosolization of the
microbe.
 The discharged microbes remain suspended in
the air on dust particles, respiratory and water
droplets.
 Illness is caused when the microbe is inhaled or
contacts mucus membranes or when secretions
remaining on a surface are touched.

12. Airborne Pathogens
Meningitis
Influenza
Pneumonia
Tuberculosis
Precautions for
tuberculosis also
lower the risk for
other airborne
pathogens
4-12
Spread by inhaling the germ
Coughing or sneezing tiny droplets of moisture into the air containing
pathogens
Pathogens can remain airborne for several hours
Pathologist
Postmortem room personnel
Agriculture workers
Veterinary staff
Health care workers

13. Food borne pathogens
 The food involved is usually contaminated with a disease
pathogen or toxicant
 Such food contains enough pathogens or toxicant necessary to
make a person sick.
 Food borne diseases (FBD) are acute illnesses associated with
the recent consumption of food
Food borne diseases are classified into:
1. Food borne infections and
2. Food borne intoxications

14. Food borne infections
 Food borne infections are caused by the entrance of pathogenic
microorganisms contaminating food into the body, and the
reaction of the body tissues to their presence.
 These can either be fungal, bacterial, viral or parasitic
 Food borne infections tend to have long incubation periods and
are usually characterized by fever

15. Food Borne Infections cont..
Bacterial food borne infections include Cholera, salmonellosis,
typhoid fever, shigellosis, Yersiniosis Escherichia coli
infection Campylobacteriosis, Vibrio parahemolyticus and
Listeriosis
Mycotic food borne infections include Candida spp., Sporothrix
spp., Wangiella spp. etc),
Viral food borne infections include hepatitis A , Norwak virus and
poliomyelitis virus

16. FOOD BORNE INTOXICATIONS
These are diseases caused by consumption of food containing:
1. Biotoxicants which are found in tissues of certain plants and
animals.
2. Metabolic products (toxins) formed and excreted by
microorganisms (such as bacteria, fungi and algae), while they
multiply in food, or in gastrointestinal tract of man.
3. Poisonous substances, which may be intentionally or
unintentionally added to food during production, processing,
transportation or storage.

17. waterborne pathogen
 pathogens in water Important causes of waterborne disease
 waterborne disease Diseases spread by contact with
contaminated water
– Bathing,
– wading
– Contact with floodwaters
– Pathogen lives naturally in the water
– Ingestion of contaminated water

18. waterborne pathogen

19. Biological Hazards Risk Assessment /Evaluation of
biological hazard exposure
Biological Hazards Risk Assessment is a process used to
 identify the hazardous characteristics of a known infectious or
 potentially infectious agent or material,
 the activities that can result in a person’s exposure to an agent,
 the likelihood that such exposure will cause harm and
 the probable consequences of such an infection.
The information identified by RA will provide a guide for the
selection of appropriate biosafety levels and microbiological
practices, safety equipment, and facility safeguards that can prevent
HAZARDS
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20. Evaluation of biological hazard exposure
 Step 1
– Identify the hazards
 Step 2
– Decide who might be harmed and
how
 Step 3
– Evaluate the risks and decide on
– precautions
 Step 4
– Record your findings and
implement them
 Step 5
– Review your assessment and
update if necessary
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21. Hierarchy of Controls
Requires a physical
change to the
workplace
Requires
worker to
wear
something
Elimination/Substitution
Requires worker or
employer to do
something
Most
Effective
Least
Effective

22. Engineering Controls
Engineering/Bioengineering controls
 Vaccines
 Prophylactic anti-viral medications
 Ventilation systems
 Engineered safe needle devices
 Automated equipment
 appropriate container and for the
disposal of liquid bio hazardous waste.

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Policies and procedures
Routine practices such
universal infection control
procedures and other safe
work procedures
Immunization programs
Training
 Sign , biohazard’s labels
 MSDS IN LAB
Administrative controls

24. Work Practice Controls
 Do not eat, drink, apply make-up, handle
contact lenses, or smoke in areas with
likely exposure to blood or OPIM
– specimen collection rooms
– testing areas
– areas where specimens located
 Do not store food or beverages in
refrigerators, freezers, coolers, shelves,
cupboards where specimens are located

25. PPE

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Prevention and Vigilance
is Your Only Cure