B5 Ollie Flashcards
Biological Agent - COSHH Definition
A micro-organism, cell culture, or human endoparasite, whether or not genetically modified, which may cause infection, allergy or toxicity or otherwise create a hazard to human health: Fungi Bacteria Viruses Protozoa
Fungi
Plant-like organis ms No chlorophyll Many produce mass of thread-like hyphae(moulds ) Reproduce through the production of spores Some produce mycotoxins (e.g. Aflatoxin) Include yeasts Examples: As pergillum flavus (Farmer’s Lung) Rhizomes stolonifer (breadmould)
Bacteria
Consist of microscopic cells – structure different from mammalian cells Typical diameter 1 micrometer Variety of shapes : Spirils Cocci Rods Multiply by binary fission Some produce resistant spores Most are susceptible to antibiotics Examples: Eschereciacoli Legionella Pnuemophila
Viruses
Smallest micro-organis ms 20 to 300 nanometers diameter
Not composed of cells , just DNA (or RNA), carbohydrate and protein Multiply by taking over the internal mechanism within cells
Do not produce spores
Not affected by antibiotics – but vaccines can us ually be produced Examples:
Common cold
Influenza
Hepatitis
HIV
Protozoa
Single celled animals Similar to human cells Typically 20 micrometers diameter Some produce cysts Examples: Cryptosporidium parvum Plasmodium vivax
Special Properties of Biological Agents (1)
Rapid multiplication:
Mean generation time in E.coli may be 10 minutes
1 cell can form billions in a few hours under optimum conditions
Rapid mutation: Mutations occur during multiplication Advantageous mutations selected Micro-organis m quickly adapt Bacterial resistance to antibiotics Viral resistance to vaccines
Special Properties of Biological Agents (2)
Incubation period :
Time between infection and development of symptoms : Legionella - 2 to 10 days
:Leptospirosis - 2 to 20 days
:Hepatitis B - 4 to 20 weeks
Special Properties of Biological Agents (3)
Infectious:
Infectious disease:
One caused by a biological agent that can be transmitted from one person to another (or from one animal to a different one) through the presence of a replicating agent
Infectious diseases known as communicable diseases or transmissible diseases
A person suffering from an infectious disease is s aid to be infectious
COSHH Regulation 6 - Risk Assessment (1)
Risk assessments to consider: Hazardous properties of the substance Information on health effects provided by the supplier The level and duration of exposure The circumstances of the work Activities s uch as maintenance Any relevant workplace exposure limit
COSHH Regulation 6 - Risk Assessment (2)
The effect of preventative and control measures
The results of relevant health surveillance
The results of monitoring
The risk presented by exposure to substances in combination The approved classification of any biological agent
Additional information
Hazard Groups -1 and 2
Group 1:
Unlikely to cause human disease
e.g. Saccharomyces cerevis iae (brewers yeast)
Group 2:
Can cause disease and may be a hazard
Unlikely to s pread to community
Us ually effective prophylaxis or treatment available e.g. Legionella, Clostridiumtetani
Hazard Group -3
Group 3:
Can cause severe human disease and is a serious hazard May s pread to the community
Usually effective prophylaxis or treatment available
e.g. HIV, Rabies virus , Anthrax, Hepatitis B
Hazard Group -4
Group 4:
Causes severe human disease and is a serious hazard Likely to spread to the community
Usually no effective prophylaxis or treatment available e.g. Ebola, Marburg, Smallpox
COSHH Regulation 7(10) - Prevention or control of hazardous substances (Schedule3)(1)
In addition for biological agents (where not reasonably practicable to prevent exposure):
Suitable signage (biohazard sign)
Specifying decontamination and disinfection procedures
Safe collection, storage and disposal of contaminated waste
COSHH Regulation 7(10) - Prevention or control of hazardous substances (Schedule3)(2)
Testing for presence outside primary confinement areas
Specifying procedures for use and transport
Vaccines where possible
Adequate hygiene measures – facilities , prohibition of eating, drinking and smoking
Containment for Group 3 and 4 agents
COSHH Regulation 7(10) - Prevention or control of hazardous substances (Schedule3)(3)
Applies to a and b below:
a) Exposure results from a deliberate intention to work with agent e.g. research laboratory
b) Exposure arises out of a work activity which is incidental and not from direct work
e. g. hospital (opportunistic infection)
Notto c below:
c) Infection does notarise out of work activity its elf e.g. one employee catches infection from another
RIDDOR 2013 - Reportable Diseases
Listed inSchedule 3 of RIDDOR:
The person at work is currently carrying out activities listed in Schedule 3 (COSHH)
The employer (or responsible person) has received written confirmation from a registered medical practitioner
Notify enforcing authority forthwith Form F2508A
RIDDOR 2013 - Dangerous Occurrence
Any accident or incident which resulted or could have resulted in the release or es cape of a biological agent likely to cause severe human infection or illness
Guidance:
Hazard Group 3 and 4 biological agents e.g. HIV and hepatitis B, C and D.
Factors in Risk Assessment
Hazard category, (Groups 1, 2, 3 and 4 of COSHH Schedule 3)
Activities and people at risk
Likelihood and nature of resultant disease
Modes of transmission
Activities and People at Ris k (1)
Individual susceptibility: Age Gender Immune s tatus (e.g. Availability of vaccines ) Sensitisation State of health Presence/absence of controls e.g. PPE Results of health surveillance
Activities and People at Risk (2)
Number of persons exposed
Duration of exposure
Activities carried out (e.g. Maintenance, cleaning) Training, competence, information
Likelihood and Nature of Resultant Disease
Virulence:
The ability of an infectious agent to cause disease
A function of the likelihood of the agent to cause infection and the seriousness of the effect that may
result Most virulent organisms are in Hazard Group 4
e.g. Smallpox - mortality rate 35%
Accidental exposure at University of Birmingham 1978
Modes of Transmission (1)
Droplet infection:
Coughing or sneezing on another person Inhalation of aerosols
e.g. Common cold, influenza, legionella Direct contact:
Touching an infected person,
sexual contact e.g.HIV, hepatitis B
Indirect contact:
Touching an infected s ubs tance/object (fomite) e.g. HIV, hepatitis B, dys entery
Modes of Transmission (2)
Faecal-oral transmission:
Usually from contaminated food or water
Contamination with faeces
e.g. Hepatitis A, salmonella, cryptosporidium, E.coli Vectors:
Transmission though another animal, usually an insect e.g. Lyme disease (ticks ), malaria (mosquito)
Biological Agents - Routes of Entry
Inhalation:
Droplets , whole agent, spores e.g. Influenza, legionella
Injection:
e.g.HIV,hepatitis B
Ingestion:
Swallowing contaminated material
e.g. Salmonella, cryptosporidium
Absorption:
Undamaged skin usually impermeable to biological agents Sexual transmission
e.g. HIV