1 & 2 Flashcards
mycoplasmas are generally extracellular except for ______ mycoplasmas
hemotrophic
what DNA virus includes Foreign Animal Disease agents ? is it E or NE?
- Poxviridae
- E
what (2) RNA virus includes Foreign Animal Disease agents? are they E or NE?
- Bunyaviridae and Paramyxoviridae
- E
Rhabdoviridae should make you think ____
RABIES
transmission routes (7)
- aerosol
- oral
- direct contact
- reproductive (mating or fetus)
- fomite (inanimate object) or traffic fomite (human/vehicle/trailer is spreading it)
- vector born
- zoonotic
aerosol transmission foreign animal diseases for both the cat and dog
- dog: Glanders (Burkholderia mallei) and Nipah Virus
- cat: Glanders (Burkholderia mallei), Nipah Virus, and Hendra virus
aerosol transmission: zoonotic diseases for both the cat and dog
- both: Anthrax (Bacillus anthracis); Bordetella bronchiseptica; Glanders (Burkholderia mallei); Nipah Virus; Plague (Yersinia pestis); Melioidosis (Burkholderia pseudomallei); pneumocytic carinii; Q fever (Coxiella burnetii); Tuberculosis (Mycobacterium spp.)
- dog: Blastomyces dermatitids; Tularemia (Francisella tularensis)
- cat: Chlamydophila felia; Hendra virus
3 reasons for obtaining laboratory dz
- disease dx
- screen for infection
- certification that animal is infection free
diagnosis of microbial infections can be done by _____, _____ and ______
- detection of pathogens (culture, PCR, Ag detection assay)
- detection of immune response (ELISA, fluorescent Ab test, complement fixation, hemagglutination direct/indirect)
- detection of lesion (histology/immunohistology, molecular probes, EM)
how dx viral infection (6ways)
- isolate cell lines
- characteristic cellular pathology
- detect viral Ag
- detect viral specific RNA/DNA
- Ab response
- EM
problems with bacterial/ fungal culture
- slow
- fastidious or non-cultivable microbes
- may ned different medias
PCR vs reverse PCR vs real time PCR
- PCR: DNA amplification
- reverse PCR: RNA amplification
- real time PCR: amplification and quantification of DNA
true / false
PCR can detect infectious agents AND discriminate pathogenic and non-pathogenic strains
true
3 reasons why PCR is great for detecting viruses
- can target sequences or sequence the viral genome
- detect soon after infection and even before clinical signs
- estimates viral load
what is one thing we 100% need to make a PCR work and have good sensitivity
clinical isolate
detection of immune response
- > acute response would show more ___ while chronic would show more____
- > it is a good screening tool to test for ____ and _____
- acute response would show more IgM while chronic would show more IgG
- Vx efficacy and negative status of group animals
equations for sensitivity and specificity
- sensitivity= (TP) / (TP+FN)
- specificity= (TN)/ (TN+FP)
equation for prevalence
( TP + FN ) / # tested
equation for accuracy
( TP + TN) / # tested
equation for positive and negative predictive value
- positive predicted value= (TP)/(TP+FP)
- negative predicted value- (TN)/(TN+FN)
2 sample sites with their own microflora
- skin
- mucosal sites
5 sample sites without their own microflora
- blood
- CSF
- joint fluid
- bladder urine
- SQ
how to prep viral samples for the lab
- use viral transport medium kept at 4C (has buffers, proteins and Abx to inhibit bacteria)
- swabs might inhibit PCR due to contamination
how to collect sample for PCR Ag detection
-collection should be aseptic and stored COLD not frozen or fixed
how to collect sample for serology
- aseptic collection with gentle handling; remove needle before dispensing into new tube
- allow to clot at room temperature -> centrifuge -> remove serum
- refrigerate or freeze
how to collect sample for histology/immunohistology
- aseptic collection
- at least 5mm thick
- fixed with 10% formalin
how to collect sample for FA (fluorescent Ab test)
- make impression on clean slide and air dry
- fix in alcohol for cytology or acetone for direct FA
- slides can be shipped unrefrigerated
how to collect sample for electron microscopy (usually for viral)
- aseptic collection
- 1 x2mm thick fixed with 2-4% glutaraldehyde
how to collect sample for feces or body fluids
- aseptic collection and FRESH sample
- do NOT freeze
what samples do we NOT want to freeze
- for PCR Ag
- feces or body fluid
what should we do for ALL samples when shipping?
- double bag it !
- biological substance label
- all must comply with the International Air Transport Association (IATA)
what special consideration do we need to think about when preparing joint fluid specimens
may need to collect in syringe with small amount of sterile heparin to prevent clotting
true / false
aspirates and biopsies are never preferable to swabs
false ! aspirates and biopsies are almost always preferable to swabs
true/ false
when collecting swabs you may use general purpose cotton swabs
false! they contain substances that are inhibitory for some bacteria and PCR
common places to collect swabs from
eyes, nose, ears, throat, skin
commercial culture swab systems work well for ______, ______ and ______
mycoplasma, fastidious respiratory pathogens and anaerobes
true / false
trans-tracheal washes/brush and broncho-alveolar lavages have a lower recovery rate for fastidious organisms then swabs
false, the recovery rate is higher -> better
urine should be refrigerated within one hrs and processed within ____hrs from collection
72hrs
blood samples from animal taking abx vs not taking abx
- no abx: can mix blood from separate collections and hold it up to 8hrs
- abx: transport immediately, note the abx given/how much/when, only one collection allowed
how much feces do you need to send? why?
5-10grams
swab does not always have enough # of organism and does not protect anaerobic/ microaerobic organisms
what are the 2 best samples for anaerobes
biopsy and aspirates
how to send intestinal loop samples (necropsy)
8-10cm long ligated intestine, some pathogens live in mucosa so only GI contents is not enough
necropsy samples: spleen, heart blood or bone marrow are preferred over liver to detect septicemic infections. Why?
liver is contaminated by retrograde spread of intestinal flora
when you’re sending lung culture, from where do we want to collect sample? Airways are best to ID what organism ?
sample just ahead of the advancing lesion is most rewarding
–mycoplasma spp.
