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
Cryptosporidosis
Caused by a protozoan Cryptosporidium parvum
Between 3 and 5 micro-metres in diameter
Carried in the intestines of fish, reptiles , birds and mammals Transmitted via infected food or water
Over 5000 human cases per year in UK
Incubation period 2-14 days
Symptoms are usually short term mild diarrhoea.
Cryptosporidosis -Controls
Avoid drinking untreated water
Ensure high standards of water treatment (e.g. In
swimming pools ) High standards of hygiene at all times
Wash raw vegetables /fruit before eating
Treat animals promptly if they have diarrhoea
Ensure people do not prepare food for 48hours
Farmer’s Lung
Infection due to inhalation of fungal spores e.g. As pergillus flavus , Micropolys porafeani
Moulds grow on jute, flax, hemp, straw and hay
Spores may set off a hypersensitivity reaction in the inhaler, leading to external allergic alveolitis
Symptoms include fever, chills , headache ,chest pain,
shortness of breath
Can lead to meningitis , blindness and endocarditis (heart infection).
Farmer’s Lung - Controls
Design and maintenance of machinery to prevent dust Ventilation/LEV
Regular cleaning/house keeping-vacuum or wet clean
Personal hygiene – clean work-clothes at end of each day
Personal clothing and hair should be kept clean, e.g. by wearing a coverall and headgear
RPE and other PPE
Information and training
Health s urveillance
e.g. questionnaires and lung function tests
Psittacosis
Caused by Chlamydophila psittaci (bacterium)
Passed from birds (parrots , pigeons , ducks ) to humans Inhalation of faeces /feathers /dus t in aerosol
Lasts several months in bird dander
61 cases in humans (England and Wales)2008 Incubation period 5-14 days
Flu-like symptoms : fever,chills , cough, weakness
Psittacosis -Controls
Preventative husbandry: Clean cages daily, remove faeces Disinfection of cages for new animals Working methods to reduce dust e.g. vacuum, wet cleaning LEV to remove aerosols PPE e.g. gloves and body protection RPE if high risk (e.g. on-farm s laughter of poultry) Information and training
Hepatitis A
Virus transmitted by infected food and drink, and is
associated with poor sanitation
Sewage workers and healthcare workers are most at risk
Incubation period 15-40 days
Symptoms fever, nausea and sickness
Jaundice appears a week later and may persist for up to three weeks Serious complications are unusual
Hepatitis A - Controls
Similar to preventing food pois oning
Good standards of hygiene especially where faecal contamination is possible (e.g. in hospitals )
Ens ure adequate cooking of food/s erve hot
Immunisation – vaccine effective for up to 10 years
Hepatitis B,C,D(1)
Serum hepatitis
Transmitted via body fluids (Blood borne viruses):
Direct contact e.g. Cuts
Splashes to the eyes , nose or mouth
Contact with contaminated sharps
Sexual transmission
Passed to the infant from the mother at birth
Hepatitis B,C,D(2)
Incubation period 2 to 6 months Symptoms: Fever Malaise Jaundice Liver damage Liver cancer 5-20% mortality rate Groups atrisk: Healthcare workers Social workers Refuse handlers etc
Human Immunodefficiency Virus (HIV) (1)
Virus that leads to AIDS
(Acquired Immune Deficiency Syndrome)
Symptoms:
Opportunistic infection, wasting
Transmission by exchange of body fluids (Blood borne virus ) Those most at risk include healthcare workers , cleaners , refuse collectors
Human Immunodefficiency Virus (HIV) 21)
Most new cases due to sexual transmission between hetero sexuals /s hared needles
5 occupational cases in UK (HPA 2011)
HIV destroys helper T-cells
Time from infection to development of AIDS 8 years Test for presence of virus ; HIV positive
BloodBorneViruses (BBVs)-Controls
Protect cuts /abrasions with waterproof dressings
Good hygiene practice and facilities e.g. hand-was hing Decontamination and disposal, use of dispos ables
Ensure that all staff are given appropriate information and training PPE – gloves , eye shields , visors , aprons , face masks , rubber
boots /overs hoes
Emergency procedures
Control of sharps
BBVs -Immunisation
No effective vaccine available for HIV Vaccine available for hepatitis A : Two doses , 2nd after 6-12 months Vaccine available for hepatitis B ( NOT C ) : Also protects agains t hepatitis D Three doses , 2nd after 1 month, 3rd after 6 months Titre checked after third inoculation Boosters required every 3 to 5years Take about 6 months to become effective
Controlling Sharps
Eliminate use
Introduce methods to prevent contact
Dis posable sharps /no re-sheathing, tongs , pick-up s ticks , ban use of bare hands
Disposal procedures e.g. Sharps boxes PPE, training and information
Report near-misses and accidents
Legionellosis
Diseases caused by legionella bacteria
Most important legionnaires disease - caused by bacterium Legionella pneumophila
Form of pneumonia, symptoms headache ,fever,
respiratory discomfort
Elderly (especially men), immuno- suppressed
suppressed, diabetics most at risk
Legionnaires Disease-ACOP
Appoint responsible person Prepare inventory Risk assessments to consider: Controls in place Type of installation Frequency of use Water temperatures Nutrient sources Location of susceptible groups Breakdowns Record and review
Legionnaires Disease - Controls
Eliminate aerosol production. e.g. remove s pray taps /
showers not used
Temperature control:
hot water systems >60oC in calorifier/50oC hot taps Cold water systems <20oC
Monitor temperatures
Cleaning of water tanks
Flushing and disinfection of showers Disinfection e.g. chlorine dioxide Remove dead-legs
Training and information to staff
Leptospirosis (1)
Weil’s Disease
Susceptible groups include:
Farm workers
Slaughterhous e workers
Sewage workers
Caus ed by bacterium Leptos piraicterohaemorrhagiae
Released in urine of rats , survives in environment for more than 1 month
Leptospirosis (2)
Enters through open cuts , gut, conjunctiva of eye Incubation period 4-19 days Symptoms: Fever High temperature Headache Vomiting Muscle pain Jaundice Meningitis Liver and kidney failure
Leptospirosis -Controls
Pest control and litter removal Waterproof plasters over cuts Protective clothing and footwear Prompt treatment of cuts Good personal hygiene e.g. hand-washing Avoid eating/smoking in areas of potential contamination Warning cards
Eschericia coli
Found in human gut
E.coli 0157 potentially mos t harmful - infectious dose <100 cells
Main reservoir cattle
High risk - petting farms /contaminated food
Enters food chain through faecal contamination
Causes hemorrhagic colitis - abdominal pain, cramps , bloody diarrhoea 5% of cases - haemolyticuremic
syndrome, anaemia, kidney failure
Eschericiacoli -Control
Good hygiene standards throughout food chain
Strict procedures to prevent contamination of meat with faeces in abattoirs
Good hygiene standards in cooking/food preparation
Eschericia coli - Control (petting farms )
Hand-was hing facilities (better than gels or wipes )
Hand-was hingafter touching animals
Separate areas for eating
Cleaning of items in contact with floor (e.g. Footwear) Education/information e.g. do not lick fingers after touching animals
MRSA (Methicillin Resistant Staphylococcusaureus )
S.aureus commonly found in nose
May cause boils , wound infections , septicaemia MRSA antibiotic resistant strain
Mainly a problem in hospitals /nursing homes
MRSA - Controls
Screen patients for MRSA
Hand was hing (staff and visitors ) before and after handling patients High standards of hygiene in
hospitals
Isolation of infected persons
Clostridium difficile
Present in gut, especially children – spore former
Antibiotics kill other natural gut bacteria; gives C.difficile advantage
Multiplies and releases toxin
Symptoms ; diarrhoea and fever
Spread on hands of healthcare s taff
Controls:similar to MRSA
Noroviruses
Winter vomiting dis eas e
Naus ea, vomiting, diarrhoea, duration 12 to 60 hours
Especially common in hospitals , nursing homes ,
schools Spread mainly faecal-oral, but also in vomit
Control:
Disinfection of contaminated areas
Good hygiene procedures
High standards of personal hygiene
Zoonoses
Infections that normally affect animals but can be
transmitted to humans
Examples: Leptospirosis Psitacosis Brucellosis Anthrax Lymedisease
Zoonoses -General Controls
Caused by bacterium Brucella abortus and Brucella mellitens is Infection from unpas teuris ed milk, cuts , direct contact, maybe inhalation
Atrisk: vets,farm workers,lab workers,slaughter houseworkers
Symptoms: fever,malaise,weakness and fatigue
Symptoms intermittent and may become chronic In cattle causes spontaneous abortion
Brucellosis -Controls
Eradicate from cattle Testing of cattle
Pasteurisation of milk Control of imports
Disinfection of contaminated areas
General Hierarchy of Control (1)
Eradication Reduced virulence Change of work method to minimise or suppress generation of aerosol ls Isolation and segregation Containment approach (Schedule 3 COSHH) Control for specific examples Sharps control
General Hierarchy of Control (2)
Immunisation Decontamination and dis infection Effluent and was te collection Storage and disposal (controlled) Personal hygiene measures Personal protective equipment Biohazard signs Base line testing and health surveillance
Containment - COSHH 2002
If Group 2 agent must have minimum contain level 2
If Group 3 agent must have minimum level 3
If Group 4 agent must have minimum level 4
If exposed to Group 3 or 4 agent, employer must keep list of employees and details (40years)
If using Group 2, 3 or 4 agent for first time, employer must notify HSE 20 working days in advance (with details)
Consignment of Group 4 agents , employer to notify HSE 30 days in advance
General Laboratory Work - Containment Level 1
Food, drink and smoking should be prohibited
Laboratory coats worn/cleaned, other PPE removed if leaving laboratory
Doors closed
Easy clean surfaces and good hygiene standards
Decontamination procedures in place, contaminated materials labelled and appropriately s tored
No mouth pipetting
General Laboratory Work - Containment Level 2
Inadditionto CL1: Restricted access Specified dis infection procedure Mechanical ventilation should create - negative pressure
Procedures creating aerosols in safety cabinet (Class 1) Benches must be routinely decontaminated
Wash basins to be located at exit
General Laboratory Work - Containment Level 3
Inadditionto CL2:
List of employees
Separate laboratory
HEPA filtration
Laboratory must be sealed for disinfection
Biohazard sign on entry
Laboratory coats must be autoclaved before laundering Class II or III safety cabinet
General Laboratory Work - Containment Level 4
Employees over 18
Extraction requires double HEPA filtration
Airlock Class III safety cabinet
High performance RPE in event of an accident
Means of outside communication
Infectious material should be destroyed within the laboratory unit
Spillage Procedure - Blood and Body Fluids
Gloves ,eye protection and a disposable apron to be worn
Disposable plastic over shoes or rubber boots if s pill extensive Contamination should be wiped up with paper towels soaked in a
suitable disinfectant (e.g. hypochlorite solution)
If broken glass is present, treat with hypochlorite, then remove glass with forceps to sharp’s bin
Dispose of towels and gloves to yellow bags labeled with the biohazard label
Hands must be washed following clearing up
