Exam 3 - Diarrheal Disorders Flashcards
what 4 diseases are common causes of acute diarrhea of adolescent-to-adult cattle?
BVD, mucosal disease, salmonellosis, & winter dysentery
what are 4 diseases that cause chronic diarrhea & weight loss?
paratuberculosis, eosinophilic enteritis, mucosal disease, & salmonellosis
what disease causes acute diarrhea with oral erosions in cows?
mucosal disease/BVD
what is the etiology of BVD?
pestivirus - RNA virus
cytopathic & non-cytopathic strains - antigenic diversity & high rate of mutation
what is the pathophysiology of BVD?
contact with infected excretions/secretions - virus is taken up by reticuloendothelial cells & replication occurs in lymphocytes & macrophages
virema occurs in the gi tract, respiratory tract, & reproductive tract & the virus is shed
what are the clinical signs of BVD?
subclinical infection, diarrhea +/- blood, fever, decreased feed intake, decreased milk production, & oral erosions
what signs of hemorrhage are seen with BVD?
petechiae/ecchymoses, bleeding from injection sites, bloody diarrhea, epistaxis, & destruction/sequestration of platelets
what signs of immunosuppression are seen with BVD?
transient leukopenia/lymphopenia, altered T/B lymphocyte/neutrophil/monocyte/macrophage function, & decreased resistance to infection
how do you end up with a PI calf from BVD?
dam gets infected with the virus 80-100 days into gestation with the non-cytopathic strain of the virus, so the fetus is immunotolerant - affected calves may be normal or stunted
how does a PI calf develop mucosal disease?
the non-cytopathic virus either mutates to the cytopathic type (most common) or the animal comes into contact with the cytopathic virus & develops an overwhelming viremia with severe clinical signs causing death
what happens if a dam gets infected with BVD 50-100 days into gestation?
abortion/stillbirth
what happens if a dam gets infected with BVD 80-100 days into gestation?
has a PI calf with persistent viremia, can be normal or stunted
what happens if a dam gets infected with BVD 100-180 days into gestation?
birth defects
what happens if a dam gets infected with BVD <125 days into gestation?
immunotolerant calf
what happens if a dam gets infected with BVD >125 days into gestation?
immunocompetent calf
what happens if a dam gets infected with BVD >180 days into gestation?
no ill effects
when would you use IHC of skin biopsies for BVD?
testing for PI calves
when would you use PCR testing for BVD?
PI calf or an acutely affected calf
T/F: calves that nurse seropositive cows for BVD will have positive titers for BVD regardless of infection status
true
what are the control measures used for BVD?
removal of PI calves - test suspected calves & whole herd when they are open instead of when they are pregnant, not wasting money
vaccination of breeding herd - MLV vaccine type I & II, not when they are stressed/pregnant because they can cause immunosuppression/viremia/abortion
how is salmonellosis transmitted?
fecal oral transmission
T/F: salmonella is a ubiquitous organism & most infections are subclinical
true
what salmonella is host-adapted to cattle?
s. dublin
what is important about salmonella typhimurium?
**
cattle & sheep are the most common host for what salmonella?
serovar c - s. newport
what is eosinophilic enterocolitis?
IBD with eosinophilic infiltrates causing a malabsorptive diarrhea that isn’t well understood
eosinophilic enterocolitis presents similarly to what other disease?
johne’s disease - causes diarrhea, weight loss, & similar age of onset
what is the treatment for eosinophilic enterocolitis?
steroids
what is the agent that causes johne’s disease?
mycobacterium avium sub species paratuberculosis - acid fast organism
what is in this picture?
mycobacterium avium sub species paratuberculosis
why is mycobacterium avium sub species paratuberculosis persistent in the environment?
persists in soil up to 1 year - alkaline soils decrease survival
resists pasteurization at 63 C for 30 minutes
several strains persist
what is the host range of johne’s?
cattle, sheep, goats, other feral & domestic ruminants with occasional reports in camelids
how is johne’s disease transmitted?
fecal oral is the biggest!!!
colostral, milk, transplacental, & coital
what are the risk factors associated with age & infectious dose in regards to johne’s disease?
neonates are at risk
increased dose = increased likelihood of infection & decreased time to patency
what breeds are predisposed to johne’s?
dairy > beef
channel island breeds & shorthorn
what concurrent disease/stressors add a risk factor to developing johne’s disease?
dietary imbalance, immunosuppressive disease, parturition, & transportation
what is the silent stage of infection of johne’s disease?
no clinical signs/ill effects - generally seronegative but may be culture positive
what is the subclinical stage of infection of johne’s disease?
potential mildly decreased productivity, often seronegative, 20% culture positive
what is the clinical stage of infection of johne’s disease?
decreased production & BCS, diarrhea, normal appetite, excessive thirst
what is the advanced clinical disease stage of infection of johne’s disease?
emaciation, fluid diarrhea, +/- edema, & weakness
for each stage 3 johne’s cows, what can you expect? what about stage 2? stage 1?
stage 3 - 1-2 animals not yet known to be infected
stage 2 - inapparent carrier adults, 6-8 animals affected
stage 1 - infected calves/livestock, 10-15 animals
what are the common clinical signs of johne’s disease in cows?
‘old cow’ disease, clinical signs are rare before 2 years of age, chronic progressive weight loss, good appetite, singular animals ill at any time, calving precipitates clinical signs because of stress
diarrhea - intermittent progressing to persistent watery without blood or casts
increased external parasite burden, dependent edema, bottle jaw
what clinical signs are seen in sheep/goats with johne’s?
chronic weight loss, watery feces are rare, younger at presentation, goats are sicker at presentation
what are some differentials for johne’s in sheep & goats?
endoparasitism, CL internal abscesses, starvation, CAE/OPP, organ failure
what tests are commonly used to diagnose johne’s disease? less commonly used tests?
serology - ELISA
fecal culture - herrold’s egg yolk & TREK liquid media, fecal PCR
less common - rectal biopsy/acid fast stain & intestinal/ileocecal lymph node biopsy culture/histopathology
what is the clinical course of winter dysentery? how long until the herd outbreak resolves?
clinical course - 3 days
2 weeks for herd
T/F: there is high morbidity & mortality associated with winter dysentery
false - only high morbidity, no mortality
what are the clinical signs of winter dysentery?
fever, fulminate diarrhea that is dark/bloody & rapid spreads, decreased milk production, inconsistent respiratory signs, & most severe in young
what is the etiology of winter dysentery?
undetermined - suspected to be similar to coronavirus because corona-like virus particles are found in feces, rising titers are seen following clinical disease, corona virus antigen in the crypt cells, & corona virus is isolated from feces
what clinical signs are associated with acute enteritis of salmonellosis?
fever, anorexia, diarrhea that is bloody/has mucus/casts, & dehydration
what clinical signs are associated with chronic enteritis of salmonellosis?
chronic or intermittent diarrhea - ill thrift in some cases
T/F: salmonellosis can cause septicemia
true
how is salmonellosis diagnosed?
characteristic clinical signs, microbiological isolation from tissues, isolation from feces (clinical vs. carriers & hematologic changes), & isolation from milk in DUBLIN ONLY
what is the treatment for salmonellosis?
do not treat the carriers!!!!!
clinical disease - appropriate antibiotics (ceftiofur), NSAIDS (flunixin), fluid therapy, acid base correction, & cull
how is salmonellosis prevented?
environmental hygiene, prevent transmission, minimize predisposing stressors, removal of carriers/reservoir, & improve passive transfer in calves
