Brucella

Question 1

What is zoonosis?

Answer 1

Infections of animals that sometiems get transmitted to humans

Question 2

Where is brucellosis found?

Answer 2

Sheep, cattle, pigs, dogs => cause infertility and abortions

Question 3

Which species of brucella most commonly affects humans?

Answer 3

B.Melitensis

Question 4

What are the risks for getting brucellosis?

Answer 4

Unpasteurized dairy
Contact with infected animals
Lab workers
CATEGORY B INFECTIOUS AGENT - Agent of bioterrorism potential

Question 5

What are the bacterial category A bioterrrorism agents?

Answer 5

B.Anthracis
Yersinia Pestis
Clostridium Botulinum toxin
Tularemia (Franciesella Tularensis)

Question 6

What are the characteristics of a category B bioterrorism agent

Answer 6

Moderately easy to disseminate
Moderate morbidity and low mortality rates
Requires enhanced CDC diagnostic capacity and disease surveilance

Question 7

Which bacterial species are under Category B bioterrorism agents?

Answer 7

Brucella
Clostridium Perfringens Epsilon toxin
EO157
Salmonella
Shigella
Burkholderia Pseudomallei
Staph Enterotoxin B
Typhus Fever(Rickettsia Prowazekii)

Question 8

What is the pathogenesis of Brucella?

Answer 8

Penetrate skin/mucous membranes -> phagocytosed by macrophages/monocytes -> carried to spleen, liver, bone marrow, lymph nodes, kidneys -> host reaction of small granulomas

Question 9

How does humoral immunity affect brucella infection?

Answer 9

Does not affect outcome -> surivives intracellularly

Question 10

What determines recovery from brucellosis?

Answer 10

T cell immunity

Question 11

What are the clinical presentations of brucella infections?

Answer 11

Sx appear 2-8 weeks after infection
Initial: nonspecific sx : Malaise, chills fatigue, myalgia, weakness, etc

Fever: Intermittent/Cyclical; Undulating fever or fever of unknown origin

Splenomegaly
Lymphadenopathyy
Hepatomegaly

Question 12

What is seen with advanced brucellosis?

Answer 12

GI sx: N/V abd pain, diarrhea, constipation
Osteolytic lesions/Joint effusion
Resp Sx

Question 13

How is brucella diagnosed?

Answer 13

Blood cultures w/ extended incubation time (~10 days)
Bone marrow -> macrophages take organism here-> high concentration

SErology: antibody titer

Increased febrile agglutinin titer

Question 14

What are the characteristics of Brucella?

Answer 14

Gram Negative Coccobacilli 
Slow Growing
REquires enriched media- chocolate
Prolonged incubation required
Tiny/small-> difficult to see stain

Question 15

How is brucellosis treated?

Answer 15

Treat for long time due to chronicity
Tx: Oral tetracyclines + aminoglycosides

Cephalosporins and Fluoroquinolones show poor activity -> pt may relapse

Question 16

How can brucellosis be prevented?

Answer 16

Control via livestock immunization
Avoid unpasteurized milk/dairy
No vaccine available