Miscellaneous Flashcards
Which CFR is Animals and Animal Products (USDA)?
CFR 9
Which CFR is drugs and GLP (FDA, DEA)?
CFR 21
Which CFR is OSHA standards (Dep of Labor)?
CFR 29
Which CFR is NHP importation (CDC)?
CFR 42 Subpart 71
Which CFR is possession, use, transfer of select agents and toxins (HHS, CDC)?
CFR 42 Subpart 73
What are overlap select agents and toxins (HHS and USDA)?
Bacillus anthracis
Bacillus anthracis Pasteur strain
Burkholderia mallei
Burkholderia pseudomallei
Hendra virus (Paramyxoviridae)
Nipah virus (Paramyxoviridae)
Rift valley fever virus (Bunyaviridae)
Venezuelan equine encephalitis virus (Togaviridae)
What disinfectants are oxidizing agents?
- Halogens: chlorine (e.g. bleach), iodine (e.g. povidone iodine)
- Peroxygens: Virkon, Peroxygard, hydrogen peroxide
What do halogens (chlorine not iodine) and peroxygens (hydrogen peroxide) kill? What are cons?
Vegetative bacteria, mycoplasma, enveloped and nonenveloped viruses, fungi, acid fast bacteria, some spores
Cons: Corrosive; concentrations can cause respiratory irritation
What do quaternary ammonium compounds kill? What are cons?
Vegetative bacteria, enveloped viruses
Cons: doesn’t get pseudomonads, acid fast bacteria, non-enveloped viruses, spores
What does iodine kill?
Vegetative bacteria, pseudomonads, acid-fast bacteria, enveloped viruses, bacterial spores
Cons: Does not get non-enveloped viruses
What does alcohol kill?
Vegetative bacteria, mycoplasmas, pseudomonads, enveloped viruses
Cons: Does not get non-enveloped viruses or SPORES
Eligibility requirements for ALAT (Assistant Laboratory Animal Technician)
high school diploma or GED: 1 year experience
Associate’s degree or higher: six months experience
Eligibility requirements for Laboratory Animal Technician (LAT)
High School Diploma or GED: three years of experience
Associate’s Degree (AA/AS) or ALAT: two years of experience
Bachelor’s Degree (BA/BS): one year of experience
Eligibility requirements for LATG (Laboratory Animal Technologist)
Bachelor’s Degree (BA/BS): Three years of experience in laboratory animal care are required.
Associate’s Degree (AA/AS): Four years of experience in laboratory animal care are required.
High School Diploma/GED: Five years of experience in laboratory animal care are required.
In a recent journal article discussing plans for measuring vibration and noise in a vivarium, most vibration reaching animals was described as being in which axis?
Z
Nuisance variables (variability in data which masks the real treatment effects) can be managed by using which study design?
Randomized block design
Using previous standards of research animal management and the American Public Health Association, what level of colony forming units is considered poor sanitation for a RODAC plate?
50-75 CFU
ABOVE 50 is bad
Mechanism for how UV-C radiation can be used to sanitize?
Produces pyrimidine dimers which damages DNA in microorganisms
Which stain is least useful for detecting amyloid in tissues?
Gram
Hydrogen peroxide concentration for fumigant decontamination
2.4 mg/L
Organisms listed most to least resistant to disinfectants
Prions > spores > Mycobacteria > non-enveloped viruses > fungi > vegetative bacteria > enveloped viruses
What groups regulate transportation of infectious substances?
Department of Transportation (DOT)
International Civil Aviation Organization (ICAO), International Air Transport Association (IATA)
Category A packaging
Infectious substance
UN 2814: ID number for substances that cause DZ in humans or in both humans and animals
UN 2900: ID number for substances that only cause DZ in animals
Category B packaging
Biological specimen (UN 3373)
How often to validate ventilation for ABSL-3Ag and -4Ag
Annually
6-8 week ‘burnout’ method best for what type of viruses?
Enveloped
Which is easier to control, the source or reservoir of an infectious agent?
These are not necessarily the same
Usually the source
Which pathogens are not readily transmitted by dirty bedding sentinels?
Sendai Virus, Hantavirus (through aerosol)
Helicobacter (host-adapted, fecal-oral)
internal/external parasites
Enveloped viruses (less stable in bedding)
Most rodent pathogens are spread horizontally. Which rodent pathogen is an exception?
Lactate dehydrogenase-elevating virus (LDV)
Spread parenterally through cell lines
Appropriate length of quarantine for rodents from non-approved vendors
Usually 4-8 wk (allows for infection, seroconversion)
OR bypassed w/ PCR testing with noninvasive samples to reduce quarantine to 2 wk (this more sensitive than indirect sentinel testing)
____ help preserve the
nutritional value of food by promoting rapid and uniform steam penetration, which allows autoclave times
to be kept short.
Presterilization vacuum cycles (removes air before the cycle so steam will penetrate faster)
What is the most common gamma radiation source?
Cobalt 60
What wavelength has peak bactericidal activity
260 nm (near peak of DNA absorption)
UV-C which is germicidal is 180-280
What type of virus is resistant to UV and gamma irradiation
Small viruses (e.g. parvo)
As are bacterial spores, protozoan cysts, and vegetative bacteria w/ highly efficient DNA repair capabilities
Don’t rely on this as primary method for gnotobiotic!
3 types of filtration based on pore size
Microfiltration - does not get viruses
Ultrafiltration - gets viruses
Reverse osmosis - gets everything including salts
3 mechanisms of chemical disinfection. Which is most effective?
- Denaturants (of protein, lipid)
- Reactants (break covalent bonds)
- Oxidants
Oxidants generally used as they get spore-forming bacteria, nonenveloped
viruses, and free-living forms of parasites.
Examples of denaturants
Phenols
Quaternary ammonium compounds
Alcohols
Examples of reactants
Aldehydes (formaldehyde, glutaraldehyde)
Ethylene oxide
Examples of oxidizing agents
Peroxygens - Peroxigard
Halogens - chlorine (bleach, chlorine dioxide), povidone-iodine
What scheme is used to define viral sensitivity to chemical disinfectants?
Klein–DeForest Scheme
What are Categories A, B, and C of Klein–DeForest Scheme?
A: Lipophilic (enveloped viruses)
B: Hydrophilic (non-enveloped viruses)
C: Intermediate (e.g. Adeno
(MAV-1,2), Reo (Reo-3), and Rota (EDIM, IDIR))
What are Categories A-D for pathogen susceptibility to disinfectants?
A: enveloped viruses, non-spore forming bacteria
B: intermediate viruses
C: non-enveloped viruses
D: bacterial spores, parasite ova and spores
*In order from least to most resistant
**B and C are switched from the Klein-DeForest
Using chlorine as an example, how do environmental factors affect effectiveness?
Increasing the pH or temperature of water
reduces the concentration of hypochlorous acid in favor of the hypochlorite (OCl−) ion, which is less biocidal
Chlorine also reacts with organic/inorganic materials making less chlorine available for disinfection
How to remove biofilms (e.g. Pseudomonas) from water systems?
Hydrogen peroxide, alkaline peroxide (hydrogen peroxide in basic solution)
Are most Mycoplasmas in cell lines, cultures etc infectious to rodents and rabbits?
No; 99% are human/bovine/swine origin
Examples of selective culture media
Enrichment media can be used – selenite broth for salmonella
MacConkey’s agar has crystal violet and bile salts to inhibit growth of G(+)
–> Lactose fermenting bacteria in pink (E. coli), non-lactose fermenters (Salmonella, Shigella) colorless
SS agar: Salmonella black
Homogenous vs heterogenous serology tests
Homogenous - everything is liquid mixed together (hemagglutination, virus neutralization)
Heterogenous - antigen attached to surface; more sensitive e.g. ELISA, IFA, multiplexed immunoassay
ELISA more high-throughput (screening) vs IFA higher resolution (confirmatory)
Examples of inclusive vs exclusive test
Inclusive: can detect multiple viruses (e.g. nonstructural protein of parvo)
Exclusive: unique to a single virus; good for confirmatory testing
Alternative to serology
Dried blood spot (DBS) - only 1 drop of blood, can be collected minimally invasively
Can use multiplexing to test for many antigens
Limitations to serology
Bacteria and fungi stimulate relatively weak adaptive immune responses - Exceptions: M. pulmonis, CAR bacillus, E. cuniculi
Require immunocompetent host
Takes time to become positive: at least 7-10 days to seroconversion
Common molecular target for PCR assays
Ribosomal genes
Types of blot assays
Southern blot = DNA
Northern blot = RNA
Western blot = protein
How to adjust cutoff for test for rare and common pathogens?
Rare: Increase cutoff to increase DSp and avoid FP
Common: Decrease cutoff to increase DSe to reduce FNs
Sensitivity is measured as the _____, which is the lowest [ ] of target analyte in a specific matrix (eg serum) that can consistently yield (+) results
Limit of detection (LOD)
Analytical specificity is defined as the ability of an assay to distinguish target from nontarget analytes, including matrix (i.e., specimen) components. What are the three components?
selectivity, inclusivity, and exclusivity
How is the analytical specificity of serologic and PCR assays determined?
Serology: amount of antigen bound to the immunoassay
solid phase
PCR: the genomic sequences to
which the primers (and probe for qPCR) anneal
Low prevalence is associated with ____ positive predictive value.
Decreased (get more FPs)
Considerations for using principle animals and sentinels for testing
Principle animals:
***Age - older animals likely seropositive but cleared the infection so PCR negative. If enzootic choose weanlings (when they lose maternal antibody protection)
Sentinels:
mature immune system, outbred stocks (cheaper, stronger immune responses), female (less likely to fight if in direct contact with principal animals)
How often to perform sentinel testing
Quarterly
3x yearly for prevalent or more common agents
1x yearly for more comprehensive panel
Best confirmatory testing methods after serologic (+) for murine rotavirus, MPV, and MNV
Rotavirus: agent cleared (seropositive result –> PCR cagemate less helpful to confirm –> serology or pooled PCR feces or IVC exhaust)
MPV: persistent infection + waning shedding (viral DNA persists in mesenteric lymph node –> test that by PCR)
MNV: persistent infection + prolonged shedding (a negative PCR would help support it was a false positive)
___ consecutive negative screens ___ days apart of 100% of cages in room are required to lift quarantine
2 at 21-28 day intervals
Genetically engineered mice at academic institutions have high prevalence of infection with which 4 pathogens (or groups of pathogens)?
Helicobacter, MNV, Pasteurella pneumotropica, parasites
The use of soiled bedding sentinels as a part of a health monitoring system is effective for which pathogen?
MHV (Coronavirus)
Environmental monitoring is helpful for what pathogen that is otherwise hard to detect?
Myobia musculi (fur mite)
Which agents have been shown to be transmitted by vertical transmission in the mouse?
LCMV, LDV, P. pneumotropica, Mycoplasma
