Tuberculosis in cattle Flashcards
caused by what
m bovis
why difficult to eradicate
wildlife reservoirs
what other species can infect bovines
m avium
other saprophytes
pathogenesis
-bacteria in respiratory tract
-survive and multiply in host macrophages in lung
-infected macrophages accumulate in lung
-inflammatory cytokines
-cellular immune response
-granuloma formation
why can they survive in macrophages
thick cell wall
clincal signs
-only evident in advacned disease
-loss of condition
-cough
-intermittent pyrexia
-supramammary lymph node enlargement
-mastitis
diangosis
-tuberculin
-IFN-y assay – important
-ELISA
-histopathology of samples, ZN staining
-isolation of m bovis
-PCR
what is not a good stain to do
gram stain
what is best stain for mycobacteria
ZN stain
what is important diagnostic test
IFN-y assay
treatment
no treatment
control
-tuberculin positive – slaughter or isolation of animal
-disinfection of farm and buildings
-BCG human vaccine (heterologous vaccine)
-DNA vaccine
tuberculin test false positives
mycobacterium phlei
tuberculin test false negatives
animals with advanced tuberculosis (IgG)
early stages of infection
tuberculin cross reactions
m avium
m paratuberculosis
nocardia species
tuberculin – single intradermal test
routine testing
simple
prone to false positives, poor sensitivity
tuberculin – comparative test
use in avian TB or Johne’s disease
more specific but more complex than SID
tuberculin – short thermal test
use in postpartum animals and in infected animals
high efficiency
time consuming, risk for anaphylaxis
tuberculin – stormont test
use in postpartum animals and in advanced cases
very sensitive and accurate
requires 3 visits, may sensitize the animal
what type of hypersensitivity is the tuberculin test
type IV delayed hypersensitivity
