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How is Johne's Disease transmitted? 4
- Fecal Oral
does Johne's Dz lead to secretory or malabsorptive diarrhea?
How does this occur?
Intracellular pathogen passed from M cells to Peyer's Patches
What is the result of type I immune reaction w/Johne's?
What C/S does this cause?
Degranulation of mast cells => diarrhea
what is result of type II immune reaction w/Johne's?
What C/S does this cause?
- Ag/Ab complex => Intestinal inflammation
- (also see type IV-delayed hypersensitivity)
Dehydration is not a prominent sign w/Johne's but why does the cow have "bottle jaw"?
How is Johne's Dx'd?
Problem with Gold Standard?
- C/S present:
- GoldFecal culture
Not practical- 12-16wks for results
Where is sample collected for diagnostics at necropsy?
What is seen under microscope?
Ileocecal junction/Lymph nodes
Acid fast organisms in macrophages
what is problem with diagnosing sheep with Johne's? 3
- No Diarrhea
- Fecal culture not reliable
- Histopath required
how is Johne's Tx'd?
- No approved tx
- Isoniazid: ⇩C/S => Shedder
what are possible outcomes if calf is infected with Johne's?
- spontaneous recovery
- dev'l clinical disease
Is there a vaccine to prevent Johne's?
- State vet can give killed vx to reduce clinical disease
- (given in brisket of calves <30d - granulomatous rxn)
what kind of bacteria is salmonella? (intra or extracellular, G-/+)
- G -
- intracellular, facultative
what are two most common types of salmonella?
Which is zoonotic?
Which has life long carrier status possible?
- S. dublin - carrier for life
- S. typhimurium - *zoonotic*
Salmonella spreads via fecal-oral transmission then causes what problems in cows? 6
where does salmonella attach?
- Tight junctions of microvilli
- MO for Intracellular replication
does salmonella cause secretory or malabsorptive diarrhea?
- Secretory & Malabsorptive
- (inflammation -protein loss, blood casts in feces)
Adults break with salmonellosis at calving/when stressed. what is main clinical sign? 5
- *fetid, watery diarrhea*
- Abrupt stop in milk
Johnes & Salmonella both cause ___
Primary differentiating factor?
- Johnes- look like crap
Host adapted form of salmonella?
What is different?
- Diarrhea + joints
how are neutriphils affects early vs. late in salmonella disease?
- early: neutropenia (lymphopenia)
- later: neutrophilia
how is salmonella Dx's?
Special considerations/uses of each?
- *fecal culture*: Intermittent shedding, Mult samples
- PCR: Bulk milk or individual poop
- ELISA: dublin
what are necropsy findings with salmonella? 5
- Mucosal necrosis
- Diphtheritic membranes
- Enlarged mesenteric LN
- GB thickened
- Hyperemic bowel in acute
When are Abx indicated for salmonella?
- Septic cases
- Won't clear carrier state
- Yes- only reduce c/s
What is an acute, contagious coronavirus that causes diarrhea but results in spontaneous recovery?
what part of the intestine is affected with winter dysentery?
colon mucosa - crypt cells
what are other signs of winter dysentery besides explosive diarrhea?
- Drop in milk
- +/- Blood/mucous in feces
- Norm TPR
Winter dysentery Tx?
Tx not needed +/- fluids
- hi morbidity but low mortality
- spontaneous recovery in 2 weeks, then have immunity