Hazard Group Pathogens Flashcards
Which viruses are Hazard Group 4?
Ebola
Marburg
Lassa
Junin
CCHF
Nipah
Hendra
Far East TBE
Macacine alphaherpesvirus 1 (formerly Herpesvirus simiae, Herpes B virus)
smallpox
Which viruses are Hazard Group 3?
BBVs
Lyssaviruses
SARS
LCMV
Hanta
LaCrosse
Rift valley fever
Dengue
TBE except Far East
Yellow Fever
Chikungunya
Zika
WNV, SLEV
Equine encephalitides
All prions except scrapie (HG2)
What legislation is in place with regards to dangerous pathogens?
COSHH - Control of Substances Harmful to Health
RIDDOR - Reporting of Injuries, Diseases, and Dangerous Occurrences Regulations
RIDDOR
equires the reporting of cases of
occupational exposure to a biological agent.
Biological agents include:
* Transmission of blood borne viruses, for example those contracted following a needlestick
incident.
* Legionnaire’s disease.
A report should be made whenever there is reasonable evidence suggesting that an occupational
exposure was the likely cause of the disease.
What are the main things that a COSHH risk assessment covers?
Warning signs
Appropriate decontamination procedures
Safe waste disposal on site and arrangements for its removal
Testing of environmental safety eg. cabinets
SOPs
Vaccines if applicable
Minimum build standards for laboratory
CL3 laboratory
What are important structural issues/ policies to be in place?
Negative pressure- supply should shut off if extract blocks to prevent positive pressure; alarm should be built in
Extract air HEPA filtered OR stack 3m high?
Filters must be checked at least 14 monthly
Separate from rest of lab
Ideally air-lock, not required
List of authorised, trained persons
Observation window/CCTV
Ideally intercom
System for lone worker to summon help
Own equipment as far as practicable
Sealable for disinfection
Bench and floor impervious for cleaning
Access to incinerator
Use safety cabinets if aerosols produced
CL4 laboratory
What are important structural issues/ policies to be in place?
Negative pressure
Supply air HEPA filters; extract air DOUBLE HEPA filtered
Requires airlock
Secure storage inside for biological material
All surfaces, including walls and ceiling, impervious for cleaning
All work in safety cabinets
On-site incinerator
Otherwise as CL3
Staff member exposed to hazard group 3 or 4 pathogen.
What policies are in place following this?
Legal requirement to keep a record of all staff exposed to HG3/4 organisms for 40 years since last exposure
Some samples such as blood/ stool may have CL3 organisms
Why is it ok to process samples in CL2 then?
If pre-test probability is low - i.e routine testing.
But if someone returns from abroad with possible Typhoid, this should be processed in CL3
BBVs are HG3, but this risk of lab transmission is very low. So can be used in CL2 safety cabinet
What is category A transport?
What regulation is it packaged under?
Category A
an infectious substance transported in a form that, if person is exposed to, could cause serious harm or death. Includes all HG4, many HG3 and C. tetani and botulinum from HG2. For HG3/HG2 only applies to PURE cultures, not clinical samples.
Also includes undiagnosed clinical samples with high pre-test probability for HG4.
Packed under regulation UN2814
What is category B transport?
Anything that is not category A
UN3373
What is a Class I safety cabinet, and what is it used for?
Protects the person and environment, not the organism. Unfiltered air pulled in through the work access point on the front, air extracted through HEPA filter. Minimum safe operator protector fraction (OPF)
is 105 –no more than 1 in 10,000 particles should escape
through front.
What is a Class II safety cabinet, and what is it used for?
Protects the person, the environment and the organism. Air drawn in through front work opening means the person is protected by directional flow. Supply air from top is HEPA filtered, works on laminar flow principles, similar to orthopaedic theatre. Can use these for HG4 work if the worker is in a full suit. There exist A and B types
– can’t use flammable/toxic materials in A
What is a Class III safety cabinet, and what is it used for?
Maximum protection–gas sealed. Shuttle things in/our either through airlock cabinet or dunk tank. Supply air is HEPA filtered, extract air is double HEPA filtered. Work through built in glove ports (same as Trexler). Flow inside is not laminar, more turbulent than that
What to do with spillage in CL3 or in a safety cabinet?
Immediately leave the vicinity, stripping off contaminated clothing
–leave this in the lab or lobby
Leave any safety cabinets running
Shower if necessary, using detergent if needs be
Make door to lab safe–lock it or big sign!
If significant spill, room should be purged of possible aerosols and then fumigated –formaldehyde or VHP
Time before safe to enter based on organism, size of spill, ACH of room (more is better)
Contain the spillage then put on appropriate disinfectant
If spill is in biosafety cabinet, generally fine to just clear it up with disinfectant then fumigate cabinet
In CL2 if no real aerosol risk can generally just clean it up with disinfectant
