IB-5 Biological Agents Flashcards
how is wells disease transmitted
causative bacteria leptospira genus is carried is rats urine. this bacteria can survive longer in water.
it can enter the body through guts and grazes and the nose and mouth
What are the ill effects of wells disease
- flu like symptoms initially
- abdominal pain
- jaundice
- liver damage as the bacteria move out of the blood and invade internal organs
- can be fatal if untreated
define the term biological agent
a micro organism such as bacterium, fungus or virus that may cause disease or infections in humans.
diseases caused by biological agents - legionellosis / weils / aids / hepatitis B
What is the causation for legionella bacteria and what places could you find it
caused by legionella bacteria - cooling towers - aerosol formation
Spa baths / saunas / steam rooms / pools in leisure facilities / water features / fire and garden sprinkler systems
causation agent and people at risk from Weils disease
leptospiriosis is caused by leptospira bacteria. - urine of rats - sewer workers / people who take part in water sports
causation agent and people at risk from AIDS (Acquired immunodeficiency Virus)
caused by HIV (Human Immundeficiency Virus) found in body fluids of infected people and transmitted by direct body fluid transfer. people at risk - paramedics, doctors & nurses
causation agent and people at risk from hepatitis B
causes by hepatitis B virus. transmitted by body fluid contact. medical staff and waste disposal people
what are the optimum growth conditions for legionella bacteria
- water temp 20-40 degrees ( hot & cold water storage taps and showers)
- killed at 60
- stagnant water (pipe work where dead legs exist)
- presence of algae, sludge and scale
- aerosol production
identify ways in which school children visiting a farm might be exposed to E. coli
- hand to mouth after, petting, feeding, touching animals or surfaces contaminated or clothing
explain practical control measures to reduce the risk of exposure to E. coli to school children in a petting zoo
briefing for teachers and children before entering / hand washing facilities (soap, hot water, drying) anti bac gel / separate areas for eating away from animals / limit contact with animals / areas supervised maintained and faeces removed / signage
what are the 4 different bio safety levels
- work with agents with are not human pathogens and present minimum risk to humans
- work with agents which cause mild human disease (hospital pathology lab)
- work with agents that will cause serious illness or potentially fatal after inhalation - treatment available
- agents that can cause serious or fatal illness and there is no treatment available
what are the requirements for bio safety level 1 & 2
- control access
- PPE
- changing facilities
- good hygiene
- working areas clutter free & decontaminated at the end of the day
- spillage procedure
- procedures to minimise the formation of aerosols and pippetting
- person responsible for bio safety management
- training
- waste disposal
- immunisation / vaccination
- control of sharps
- health surveillance
- biological safety cabinet
- spacious with impervious wipeable surfaces
- self closing doors
- autoclave
- mechanical ventilation
- vision panels / CCTV to see what is going on
what controls are needed for Bio hazards level 3
the same as 1 & 2 plus..
- signs show bio safety level and supervisor
- solid front wrap around coveralls and shoe covers
- biological safety cabinets for open manipulations
- respiratory equipment needed
- separate from other areas to restrict traffic flow
- anteroom to maintain pressure in lab
- sealable room for decontamination
- hand washing stations - with hands free controls
- HEPA (high efficiency Particle air filter)
- mandatory medical examination
- medical contact card
what controls are needed for bio safety level 4
same as level 3 plus…
- no lone working
- complete change of clothing required before entering the lab
- personnel training on emergency extraction of casualties
- communication between inside and outside
- in a separate building with controlled access
- negative air pressure maintained outgoing air HEPA filtered
- ## containment drains
describe the 3 classes of microbiological safety cabinets
class 1 = open fronted where air is drawn in through a HEPA filter and discharged to the atmosphere - only protect the operator from agents which might pose infection from the airborne routes
class 2 = open fronted where air is drawn in, exhausted through slits in the front base of the cabinet then filtered through the HEPA filter. air circulation forms a current to prevent the escape of aerosols back into the lab - suitable for risk group 2 and possibly 3
class 3 - totally enclosed, leakproof cabinets where the operator works through glove ports. air is drawn in and extracted through the HEPA filter. suitable for risk groups 3 & 4
