Brucella Flashcards
Brucella is a gram _______ bacteria.
Negative
[coccobacilli, non-motile]
True/False. Brucellosis is a reportable disease.
TRUE!
True/False. Brucella is an obligate symbiotic and obligate pathogen.
True.
True/False. Brucella is a facultative extracellular bacteria.
False. It is a facultative intracellular bacteria.
Which species of Brucella affects mainly goats and sheep?
B. melitensis
Which species of Brucella affects cattle?
B. abortus
Which species of Brucella affects swine?
B. suis
[also hair, reindeer, and carbiou]
Why is it difficult to differientiate between Brucella species?
All species have high genetic homology
Need diagnosis and identification
Which species of Brucella is the principle cause of human brucellosis?
B. melitensis
Which type of animals typically spread Brucella?
Female animals
[can cause abortion, fetus and especially placenta contains a huge amount of bacteria]
What is the general pathogenesis for B. abortus? What is important to note about this pathogensis?
Infection takes place on mucosa (oral) and wounds
Then spreads to regional lympnodes and other lymphnodes for 1-6 week incubation period
Then spreads to target organs
IMPORTANT: when Brucella is spreading to lympnodes it is intracellular and “hiding”. This means there are NO SYMPTOMS! So your cows can be infected for up to 6 weeks and you have no idea.
Do you need a high concentration of Brucella present to become infected?
No, very low concentrations of bacteria are sufficient for infection.
Can cows infected with B. abortus have normal partus?
Yes, in the result of normal partus from an infected cow, the calf will be a carrier - this is dangerous
Which species of Brucella produce smooth colonies? Why is this important?
B. melitensis, B. abortus and B. suis
These are the zoonotic species of Brucella and they have high virulence
[not a stable phenotype, can dissociate to rough colonies which is unfavorable for growth conditions]
Which species of Brucella produces rough colonies? Why is this important? Which virulence factor do these species lack?
B. ovis and B. canis
These species have a lower virulence than species that produce smooth colonies
They lack O-polysaccharide
What component of the B. abortus cell wall is responsible for its preferential location (reproductive organs and mammary glands)?
Erythritol
When will you typically see carriers infected with B. abortus exhibiting symptoms (abortion or transfer to fetus)?
When immunity goes does down the bacteria can begin to multiply
[CFR introduction during pregnancy - forget what this is but its like a hormone or something that lowers immunity]
What kind of immunity do you need for a vx for B. abortus to be affective? Which mutants are typically in these vaccines?
Both humoral and cellular immunity needed for vx
AroC mutants and DnaK mutants
The _____ of a test is the chance that the test is postive when the investigated animal is effectively affected by the disease.
Sensitivity
TP/TP+FN = Positive predicitive value
The ____ of a test is the chance that the test is negative in the absense of a disease.
Specificity
TN/FN+FP = Negative predictive value
What is the optimal test for B. abortus?
No optimal test available.
Need testing protocol that consists of different tests with differences in sensitivity and sepcificity.
Usually: Intradermal test and IFN-gamma test
Which bacteria will interfere with B. suis infection and give false positives?
Yersina enterocolitica O9
Is B. suis reportable?
Yes! It is more pathogenic than B. abortus and zoonotic to hunters.
Which species does B. suis affect?
Wild boars
[eradicated in domesticated swine]
