1. …health hazards associated with exposure to biological agents
BIOLOGICAL HAZARDS
…health hazards associated with exposure to
biological agents

2. Definitions
Biohazard – organisms or products of organisms that present a risk to humans
Organism – a living thing, such as a germ, plant, animal, or human that may consist of several parts, with each part specializing in a particular function
Microorganism – a minute organism, such as microbes, bacteria, cocci, viruses, molds, etc.

3. Development of Biosafety
Army at Fort Detrick – Frederick, Maryland
Researching biological warfare agents
1941 – Chemical Warfare Services
American Society of Microbiology served as advisors to CWS
1970’s – Recombinant DNA technology
1980’s - Appearance of HIV
1991 – OSHA’s Bloodborne Pathogens Program (29 CFR )

4. RECENT INCREASED AWARENESS OF BIOHAZARDS
Newest subset of focus
Contributing to awareness
Legionnaires’ disease
AIDS epidemic
rDNA technology anthrax
Specialists exist but their numbers are small
S/H/E professionals have become involved

5. Occupational hazards…
Healthcare
Hepatitis, tuberculosis, infections
Infections categorized as:
Community acquired – transmitted to either patients or workers
Occupationally acquired – resulting from worker exposure
Nosocomial – hospital-acquired infections of patients
Research facilities
Q fever, hepatitis, typhoid fever, tuberculosis, dermatomycosis
Percutaneous inoculation (needles/syringes, cuts or abrasions from contaminated items, and animal bites/scratches); inhalation of aerosols, contact between mucous membranes and contaminated material (hands and surfaces), and ingestion
Agriculture
Workers may be exposed to infectious microorganisms that are associated with the plants or animals
Food and grain handlers, farmers, laborers – may be exposed to parasitic diseases
Processors who handle animal products – may acquire bacterial skin diseases from working with contaminated hides, infected with contaminated fish, meat or poultry, Bacterial infections from exposure to feces from infected turkeys, geese, ducks, etc.
Animal facilities/Veterinary practices
Bites, scratches, parasites, diseases, allergens
Biotechnology facilities
Genetically engineered bacteria, fungi, plant and animal cells for development of products
Miscellaneous occupations
Workers maintaining water systems (legionella); pet shops; zoos; wood-processing facilities (fungi); sewage workers (bacteria, virus, parasites); forestry workers (Rocky Mountain spotted fever, lyme disease, viruses and bacteria from ticks, fungi); child care workers (bacteria (shingles), viruses (measles, chickenpox); public safety workers (bloodborne pathogens, viral respiratory diseases (influenza).

6. Biohazards are…
Inherently different from chemicals, physical agents, carcinogens, etc.
BUT, recognition, evaluation and control still can be applied

7. Biological materials typically…..
Have no threshold level of exposure, i.e., dose and response relationship
Are ubiquitous in the environment so the idea of “permissible exposure limits” is inappropriate
Are affected by biological competition rather than behaving in an additive or synergistic way
Interact with the host and its environment to produce the adverse effects

8. 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.

9. Factors affecting infection and exposure
Modes of transmission
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, infection of fetus, work practices

10. 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

11. Some common biological agents
Bacteria
Viruses
Rickettsiae
Fungi
Parasites

12. BACTERIA Simple, one-celled organisms Cocci, bacilli, spirilla
Some are pathogenic, some are harmless, some are even useful
Broken skin is particularly vulnerable
“Food poisoning” in mass

13. VIRUSES Smallest known organisms Living (?) non-cellular entities
Are “obligate parasites” & cannot survive without living cells
Common occupational exposures to animal virus, poxvirus & arbovirus

14. RICKETTSIAE Bacteria-like but smaller Are obligate parasites
Transmitted to humans via bloodsucking arthropods (fleas, ticks & lice) or through the air
Responsible for typhus and Rocky Mountain spotted fever

15. FUNGI Broadest spectrum among biological agents
Are either parasitic or saprophytic
Hypersensitivity due to inhaled fungal antigens
Fungal disease is rare but includes ringworm & athlete’s foot

16. PARASITES Parasitic to plants or animals
Diseases include malaria and other blood and GI infections
Dermatitis and other skin-related ailments due to mites and chiggers, etc.

17. Legionnaires’ Disease
Caused by legionella pneumophila, a bacterium
Presence possible if moisture, elevated temperature, oxygen and nourishment available
Clearly can be transmitted through air and perhaps other ways
Symptoms resemble a form of pneumonia and can be treated accordingly
About 15% of known cases have been fatal

18. Tuberculosis (TB)
Bacterial disease caused by Mycobacterium tuberculosis
Some populations are at greater risk
Transmitted by inhalation of infectious droplet nuclei suspended in air
Symptoms
Early on: fatigue, fever, weight loss
Later: Hoarseness, cough, hemoptysis (blood-tinged sputum), lesions in respiratory tract

19. Acquired Immune Deficiency Syndrome (AIDS)
Caused by HIV, a virus
Transmitted via sexual contact, sharing of needles and transfused blood
Symptoms include tiredness, fever, night sweats, weight loss
No single test as diagnosis
Treatment (at present) cannot cure or restore the immune system

20. Anthrax Caused by spore-forming bacterium Bacillus anthracis
Found in imported animal products
Types of anthrax
Cutaneous anthrax
Inhalational anthrax
Gastrointestinal anthrax

21. Cutaneous Anthrax Most common naturally occurring infection
Incubation period of 1-12 days
Symptoms:
small, raised bump
ulcer with black center
fever, headache, malaise

22. Inhalational Anthrax Most lethal form
Incubation period of 1-7 and possible 60 days
Symptoms:
sore throat, fever, muscles aches
respiratory failure and shock
Fatality rate of approximately 75%

23. Gastrointestinal Anthrax
Follows consumption of raw or undercooked meat
Incubation period of 1-7days
Symptoms:
sore throat, fever
loss of appetite
nausea & vomiting
Fatality rate between 25%-60%

24. SUMMARY
A tremendous variety of biological materials exists as potential exposure agents.
Effects of bio-hazardous agents are subtle and slow in developing.
There is increasing concern about, and interest in, biological materials.
Bottom-line: biohazards are (and must be) treated with extraordinary caution.