topic 2: Occupational Hazards/Biosafety Levels

Question 1

physical hazards

Answer 1

• animal bites/scratches
• flammable materials
• low lighting in animal rooms
• inadequate housekeeping
• sharps
• radioactive materials
• ergonomic demands
• noise

Question 2

animal bites/scratches: how can it be avoided? what to do?

Answer 2

• proper training in animal handling techniques
• be aware of environmental factors intrinsic to the animal
• have knowledge of animal behaviour
• if bitten, cleanse thoroughly with running water and soap
• identify the animal and report to the veterinarian who may choose to quarantine the animal
• report to the supervisor and seek further medical attention if needed
• record details of the accident in the Accident Reporting Form

Question 3

flammable materials: classes of fires

Answer 3

• class A fire: generable combustible material such as wood, paper, cloth e.g. bedding, paper gowns, plastic cages, etc.
• class B fire: flammable gases and liquids such as oil & paint, e.g. flammable solvents used for cleaning floors & sterilising equipment
• class C fire: flammable gases, liquids, & electric equipment, e.g. lightning, wet vacuums, automatic cage-washers, etc.
• class D fire: combustible metals such as magnesium, sodium and potassium

Question 4

low lighting in animal rooms: why is the lighting low? what hazards does it pose?

Answer 4

• in animal care rooms, light cycles may vary and most animals receive only artificial light
• animals may be kept in rooms with single-colour lights (typically red) or very low light
• poor lighting = visual fatigue or safety hazards e.g. trips, slips & falls
• humans need adjustment periods for the eyes to become accustomed to the colour or light level in the rooms

Question 5

sharps: how to mitigate the hazard?

Answer 5

• install puncture-resistant and leak proof containers for sharps (sharps bin)
• appropriate restraint or sedation of the animal during procedures entailing the use of sharps
• properly dispose of sharps in official sharps bins
• never recap a needle unless necessary (if necessary, use the one handed method or recapping device)

Question 6

radioactive materials: what are the hazards? how to mitigate?

Answer 6

• radiation (radionuclides) can present hazards through inhalation, ingestion, skin contact & proximity
• outside the body = external hazard
• ingested, inhaled or absorbed = internal hazard
• label animal cages with coloured tape containing the appropriate logo
• caution signs on animal room doors listing the radioisotope being used & name of the principal investigator (PI)
• personnel must not handle irradiated animals or bedding unless they have proper radiation safety training
• proper disposal plan for irradiated animals/bedding

Question 7

ergonomic demands: what are they? how to mitigate?

Answer 7

• injuries that result from repetitive small stresses (cumulative injuries, e.g. carpal-tunnel, tennis elbow, back injuries)
• vary tasks to lessen repetitions (take short breaks to stretch, or do another activity involving another set of muscles)
• re-engineer tasks or re-design equipment to require fewer repetitions with less strain
• anyone lifting heavy loads should be physically fit, avoid any sudden movements and use a 2-handed lifting technique
• use of lifting equipment, automation or splitting the load can reduce the risk of injury

Question 8

noise: what are the hazards? how to control the hazard?

Answer 8

• chronic noise-induced hearing loss, speech difficulties, loss of concentration, increased fatigue and distraction
• OSHA limits employee exposure to noise to 90 decibels measured on the A scale of a standard sound-level metre at slow response (dBA) averaged over an 8 hour shift
• if levels exceed 85 dBA, exposed employees must participate in a hearing-conservation programme
• the programme includes monitoring, audiometric testing, hearing protection, training & record-keeping
• can occur in cage washing areas or dog/pig holding units
• apply engineering controls, administrative controls or PPE (e.g. earplugs, earmuffs) to control the hazard

Question 9

chemical hazards

Answer 9

• flammability, corrosiveness, reactivity, explosivity and toxicity are the hazardous properties of chemicals
• e.g. carcinogens, allergens, irritants, mutagens & teratogens
• sources of exposure include disinfectants, pesticides, volatile anaesthetic gases & chemicals for preserving tissues (e.g. chlorox, acids, aldehydes, formalin)
• controlled drugs & items of potential abuse (e.g. ketamine)
• monitor the exposure to waste anaesthetic gases in operating rooms
• burns & irritations of the skin are the most common chemical injury associated with animal care and use
• adopt good practices, use PPE & safety equipment
• label all chemicals & store them in safe places
• install safety devices such as eye-wash stations & fume cupboards
• be familiar with the chemicals being used by consulting the Material Safety Data Sheet (MSDS)
• MSDS available in cage wash areas that describe each chemical used, the hazard it poses & procedures to follow in case of exposure

Question 10

biological hazards

Answer 10

• allergies & zoonotic diseases (e.g. blood borne pathogens, body fluids, animal skin, etc.)
• must be clearly indicated by standard biological warning signs giving the type & degree of risk and the person responsible (e.g. danger - infectious materials)
• infection may be acquired via ingestion, inhalation, eye contact, skin lesions or bites (animals can be a source)
• cages & racks should be demountable, autoclaveable & labelled to indicate their infectiousness
• all refuse & carcasses must be disposed of carefully, preferably by autoclaving & incineration
• sterilisation facilities should be available in an animal house

Question 11

zoonotic diseases…

Answer 11

• potential hazard to researchers/technicians when they work with animals
• rare when working with animals bred for research as opposed to wild caught animals, but still possible especially if the experiment involves diseases & infected animals
• personal hygiene is a critical barrier to the transmission of zoonoses, must be reinforced regularly!
• keep lab animals SECURED against wild rodents (to prevent breeding)

Question 12

haemorrhagic fever with renal syndrome (HFRS)

Answer 12

• Hanta RNA virus (Bunyaviridae)
• typically transmitted by striped field mice but there are also similar viruses found in other rodents
• transmitted by aerosol
• rodent respiratory secretions, saliva, urine, faeces, animal bites, when dried materials contaminated with rodent excreta is disturbed
• contaminated wounds, conjunctival exposure or ingestion
• initial symptoms begin suddenly: intense headaches, back & abdominal pain, fever, chills, nausea, blurred vision
• later symptoms can include: low blood pressure, acute shock, vascular leakage, acute kidney failure (causing severe fluid overload)
• mortality rate of HFRS is around 5-15%
• must be handled in BSL 3 or 4 labs

Question 13

lymphocytic choriomeningitis (LCM)

Answer 13

• caused by Arena ssRNA virus
• associated with Lassa fever & Argentine and Bolivian haemorrhagic fevers
• infected naturally: mice, hamsters, guinea pigs, nonhuman primates, swine, dogs
• transmission is by inhalation or contamination of mucous membranes/broken skin with tissue/fluid of an infected animal (e.g. contaminated bedding materials/fomite, can be in utero or early in neonatal period)
• symptoms similar to influenza-like disease, progressing to meningitis & coma
• can be treated
• mortality rate is less than 1%

Question 14

murine typhus (a.k.a endemic typhus)

Answer 14

• caused by rickettsia typhi bacteria in rats
• often confused with viral illnesses
• transmission by aerosols/accidental parenteral inoculation/bites from natural ectoparasitic vectors
• symptoms: fever, headache with encephalitis (inflammation of active brain tissue), myalgia and a rash
• death may occur in the elderly, severely disabled, or patients with a depressed immune system
• highly treatable with antibiotics e.g. tetracyline and chloramphenicol

Question 15

rat bite fever

Answer 15

• caused by gram negative bacteria streptobacillus moniliformis or spirillum minor present in oral and respiratory passages of rats
• transmission by bites/scratches/ingestion of contaminated products/urine/bodily secretions of an infected animal
• asymptomatic in rats
• symptoms: diarrhoea, hepatitis, septicemia (sepsis), arthritis, haemorrhage in mice
• in Strep. moniliformis infection, patients develop chills, fever, malaise, headache, muscle pain and then a maculopapular or petechial rash
• arthritis occurs in 50% of Strep. moniliformis cases

Question 16

salmonellosis

Answer 16

• salmonella bacteria (worldwide)
• transmission by faecal oral route from infected animal to humans, contaminated water or direct contact with infected animals
• non-specific clinical signs in infected animals
• infected humans: acute & sudden gastritis, abdominal pain, diarrhoea & fever
• personnel should use PPE and maintain personal hygiene & sanitation measures as prevention methods

Question 17

plague

Answer 17

• bacterium called yersinia pestis
• transmitted from animal to animal & animal to human via bites of infective fleas, inhalation of contaminated droplets expelled from coughing of infected persons/animals
• most common symptoms: swollen/tender lymph gland, fever, chills, headache, extreme exhaustion
• may progress to septicemic plague with dissemination of the organism to diverse parts of the body e.g. lungs
• mortality rate is 15%

Question 18

leptospirosis

Answer 18

• caused by bacteria of the genus: leptospira
• humans get infected via skin abrasions/mucous membranes
• direct contact with water, food or soil containing urine or tissues from these infected animals
• symptoms: high fever, severe headache, chills, muscle pain, vomiting, red eyes, abdominal pain, diarrhoea, a rash & possible jaundice
• kidney damage, meningitis, liver failure & respiratory distress may also occur
• in rare cases, death
• treated with antibiotics e.g. doxycycline or penicillin

Question 19

laboratory animal allergy (LAA)

Answer 19

• may develop when repeatedly exposed to animal allergens (e.g. urine, dander, saliva, serum)
• allergens are unique in each animal species
• route of exposure to allergens include: inhalation, direct contact with skin/mucous membranes/eyes, percutaneous e.g. animal bites & needle punctures

Question 20

people at risk of developing LAA

Answer 20

• those who have past history of allergies to pets
• smokers
• those who suffer from other allergies (e.g. hay fever/nasal allergy, eczema, asthma, etc.) may develop LAA earlier, faster, or more severely than others

Question 21

main symptoms of LAA

Answer 21

• results from the release of biochemical mediators and the generation of inflammation in the tissues induced by the IgE response
• dependent on the individual’s level of exposure to the laboratory animal allergen
• rhinitis: blocked/runny nose, sneezing
• conjunctivitis: irritation, watering eyes
• skin rashes: eczema/rash
• asthma: cough, wheezing, chest tightness

Question 22

animal biosafety levels

Answer 22

• the institutional management must provide facilities, educate staff & establish practices that ensure appropriate levels of environmental quality, safety & care.
• facilities for laboratory animals used in studies of infectious/non-infectious diseases in risk groups 1-4 should be physically separate from other activities such as animal production, quarantine and clinical labs.
• consider the nature of animals, their natural ecto- and endoparasites, zoonotic diseases which they are susceptible, and the possible dissemination of their allergens

Question 23

biosafety level 1 (ABSL-1)

Answer 23

• basic teaching and research
• microorganisms that are unlikely to cause disease
• no special safety equipment needed, can be open bench work (lab coats/gowns/uniforms)
• lab coats worn in the animal room cannot be worn in other areas
• only authorised persons can enter the facility
• read & follow safety manual instructions before entering
• any eating, drinking, storing, handling of contact lenses, applying cosmetics & storing food for human use only in designated areas. not allowed in procedure rooms!
• perform the procedures carefully to minimise the creation of aerosols
• decontaminate work surface after use or after any spill of viable materials
• make sure insect & rodent control programmes are in effect
• wash hands after handling animals and before leaving the facility
• animal room doors should open inwards & self-close!
• cages should be washed manually or in cage washers in 82 degree celsius water

Question 24

biosafety level 1 (ABSL-1) facility

Answer 24

• separated from areas that are open to unrestricted personnel traffic within the building
• designed for easy housekeeping & cleaning
• windows not recommended
• if there are floor drains, make sure the traps are always filled with an appropriate disinfectant
• no recirculation of exhaust air should occur.
• animal rooms are maintained with negative pressure (compared to adjoining hallways)

Question 25

biosafety level 2 (ABSL-2)

Answer 25

- primary health services, diagnostic services & research - pathogens that can cause disease but there are effective treatment and preventative measures are available - open bench + BSC for potential aerosols - includes almost all practices mentioned in ABSL-1 except for some differences - access to the animal room should be limited. Fewest number of individuals possible - all infectious samples must be collected, labelled, transported & processed in a manner that contains/prevents transmission of the agents - all wastes from the animal room must be transported in leak-proof, covered containers for appropriate decontamination (autoclave prior to incineration) - biohazard sign on the animal room entrance (hazard ID, contact info, entry requirements) - autoclave + clean + wash to decontaminate cages - needle locking syringe or disposable needle syringe units should be used for injection or aspiration of any infectious fluids (then disposed in puncture resistant sharps bin

Question 26

biosafety level 2 (ABSL-2) facility

Answer 26

- same as ABSL-1 facility except: - autoclave (to decontaminate infectious waste) - hand washing sink where infected animals are housed as well as other places in the facility - exhaust air is discharged to the outside without being recirculated to other rooms

Question 27

biosafety level 3 (ABSL-3)

Answer 27

- special diagnostic services, research - pathogens that usually cause serious disease but does not spread from one individual to another, with treatment and preventative measures are available - BSC and/or other primary devices for all activities - standard practices from ABSL-1 and 2 are applied - autoclave cages BEFOREEE removing bedding/cleaning/washing - decontaminate equipment according to local regulations BEFOREEE packing/transport for repair & maintenance - spill procedure: only personnel who are trained professionally are to clean up spills - provide medical evaluation, treatment & surveillance are provided as appropriate, maintain written records - materials not related to the experiment are not permitted in the animal room - used gloves must be autoclaved with other animal wastes before disposal - wrap-around gowns (contain appropriately until decontamination or disposal) - NOOOO FRONT-BUTTON LABORATORY COATS - face/eye & respiratory protection must be worn by all personnel entering animal rooms housing NHPs - boots, shoe covers, protective footwear & disinfectant foot baths are available & to be used when indicated

Question 28

biosafety level 3 (ABSL-3) facility

Answer 28

- 2 sets of doors for entry from corridors or other contiguous areas - the doors should be at least 2 meters/7 feet apart so that it is IMPOSSIBLE To hold both open at once - animal room doors: self-closing, opening inward - interior surface of walls, floors & ceiling must be water resistant - a foot or elbow automatically operated hand-washing sink will be fixed in each animal room near the exit door

Question 29

biosafety level 4 (ABSL-4)

Answer 29

- for dangerous pathogen units! serous disease that can be transmitted, NO treatment & preventative measures. - class III BSC or positive pressure suits in conjunction with class II BSC's filtered air - standard and special practices of ABSL 1-3 are applied - personnels work in PAIRS - based on risk assessment, may use squeeze cages - disposable cages (no cleaning or washing. autoclave before disposal) - enter and leave the facility only through clothing change and shower rooms - remove personal clothing in the OUTER clothing change room! keep them there!!! - complete laboratory clothing INCLUDING undergarments, pants/shirts, shoes, gloves - one-piece positive-pressure suit that is ventilated by a life support system (alarms, emergency backup breathing air tanks) - when exiting, remove laboratory clothing in the INNER clothing changing room - shower each time they leave the facility - sterilise soiled clothing in an autoclave - supplies & materials to be taken into the facility will enter by way of the double door autoclave, fumigation chamber (which is decontaminated between use) - infected lab animals infected with BSL-4 agents must be housed in class III BSC - disposable material, no cleaning, autoclave before incineration!!!

Question 30

biosafety level 4 (ABSL-4) facility

Answer 30

- all requirements for ABSL-1 to 3 + additional reinforcement - specially designed suit area for fitting a one-piece positive pressure suit: entry is through an airlock fitted with airtight doors, air pressure in the suit area is lower than that of any adjacent area - chemical shower is provided to decontaminate the surface of the suit before the personnel leaves the area - emergency communication systems in the facility - individual supply and exhaust air ventilation system (suit) - directional air flow is required to assure inflow from areas outside the facility towards the areas of highest potential risk within the facility (NOT the other way around!!! HIGH RISK AIR CANNOT GO TO THE LOW RISK AREAS) - manometer (pressure measurement) with alarm are fixed to monitor pressure levels in different areas in the facility