Lecture 14 (Biohazards) Flashcards
Biohazard
Biological substances that threaten the health of living organisms
Sources include bacteria, viruses, and other animals
Legistlation
Federal Human Pathogens and Toxins Act
Health of Animals Act and Regulations
Transportation of Dangerous Goods Act
Standards and Guidelines (CFIA)
Containment Standards for Facilities Handling Aquatic Animal Pathogens (CFIA)
Examples of Biohazards
Severe Acute Respiratory Syndrome Hepatitis C HIV/AIDS Swine Flu Avian Flu Salmonella
Classification: Category A
Infections affecting animals and humans
Standards and Guidelines (BMBL)
Biosafety in Microbiological and Biomedical Laboratories
Classification: Category B
Infections affecting animals only
Classification: Category C
Substances transported for diagnostics and investigative purposes
Agents and Sources
Bacteria Viruses Fungi Parasites Blood borne Pathogens
Bacteria
Simple one-celled organisms
Can be pathogenic, harmless or useful
Broken skin is vulnerable
Viruses
Living non-cellular entities
Cannot survive without living cells
Common occupational exposures to animal virus, poxvirus and arbovirus
Reckettsia
Similar to bacteria but smaller
Transmitted to humans via bloodsucking
Responsible for typhus and Rocky Mountain fever
Parasites
Parasitic to plants or animals
Diseases include malaria, and other blood infections
Dermatitis and other skin problems are due to mites and chiggers
Fungi
Either parasitic or saprophytic
Hypersensitivity due to fungal antigens
Fungal disease include athlete’s foot and ringworm
Toxins
Poisonous substance produced by a biological organism
eg. cholera toxin, botulinum toxin
Risk Assessment
A measure of the exposure probability, resulting in an adverse health effect
Risk = function (Severity x Probability)
Risk Assessment Considerations
- Pathogenicity/Virulence ability of organism to cause disease/degree
- Availability of effective prophylactic and therapeutic treatments
- Measure the mode of transmission and route of infection
- Host Range number of species it can infect
- Natural Distribution Region where pathogen is naturally found
- Impact of Release
RG 1
Low individual and community risk
Not capable or unlikely to cause disease in humans or animals
RG 2
Moderate individual and low community risk
Can cause serious disease but chances are low
Effective and permanent treatment available
RG 3
High individual and low community risk
Likely to cause serious disease
Effective and permanent treatment available
RG 4
High individual and community risk
Likely to cause serious diseases and death
Spread risk high and treatment may not be available
Containment Levels
Aerosol Generation Quantity Concentration Type of Proposed Work Shedding
Containment Level 1
Do not cause disease in healthy humans.
eg. E coli
Containment Level 2
Potential hazard to personnel and environment:
eg. Salmonella
Containment Level 3
Can cause serious/lethal disease via inhalation:
eg. SARS Virus
Containment Level 4
Can be easily aerosol transmitted and cause fatal diseases in humans with no possible treatments
eg. Ebola virus
Hierarchy of Controls
Engineering Controls
Administrative Controls
PPE
Engineering Controls
Air Handling
- Inward directional air flow to prevent the escape of biohazards
- Filtration
HEPA Filtration
High Efficiency Particulate Air Filtration Captures 99.97% of particles through: Impaction Diffusion Interception
Class 1 Biosafety Cabinets
Provide personnel and environmental protection
No product protection
Class 2 Biosafety Cabinets`
Provide personnel, environmental and product protection
Further divided into sections A1,A2,B1,B2
Class 3 Biosafety Cabinets
Product protection, and Maximum environmental and personnel protection
Designed for RG4 work
Complete enclosure
Administrative controls
Work with animals, children, people known to be infectious
Large quantities, high concentrations
Transport
PPE
Gloves Eye protection Lab Coats Face Mask Suit with respirators
Decontamination
Process by which materials rendered safe to handle and are reasonably free of micro-organisms/toxins
Steam Sterilization
Effectiveness dependent on:
Temperature
Length of Time
Ability of the steam to penetrate the load
Chemical Disinfection
Usually for equipment and work surfaces Effectiveness dependent on micro-organism and disinfectant as well as: Organic load Concentration Contact time (and more)
Gaseous Decontamination
Used in higher containment zones
eg. Formaldehyde, chlorine dioxide, etc.
Irradation
Gamma radiation
- good for heat sensitive materials
Ultraviolet
- only effective for airborne or surface contamination
Incineration
Effectiveness dependent on:
Equipment design
Time
Temperature
Effluent Treatment
Treatment of liquid wastes prior to release to sanitary sewer
Typically heat bases
Required for high containment zones (CL 3+)
