BRUCELLOSIS

1
BRUCELLOSIS

• Worldwide a a major source of disease in domestic
  animals and humans
• Major zoonotic disease worldwide
• Other names for human disease
• undulant fever, Malta fever, Mediterranean fever

2
BRUCELLOSIS

• 1861 British army physician (Marston) published
  description of Mediterranean gastric remittent
  fever
• 1886 Isolated by Sir David Bruce from soldier
  with Malta Fever named it Micrococcus
  mellitensus
• 1897 Bernard Bang, Danish veterinarian/physician
  , first isolated B. abortus from cattle
• Relationship of both isolates recognized by Alice
  Evans renamed Brucella in honor of Bruce

3
BRUCELLOSIS
4
BRUCELLOSIS

• Microbiology
• Gram negative coccobacilli
• Non-spore forming
• Lack capsules
• Non-motile (no flagella)
• Metabolism
• primarily oxidative
• aerobic to microaerophillic (5-10 CO2)
• slow growth _at_ 37C on enriched medium

5
BRUCELLOSIS

• Microbiology
• Classification
• Species level based on colony morphology (rough
  or smooth), serum requirement, phage lysis, and
  biochemical reactions (oxidase and urease)
• Antigenic (biovar) classification
• For smooth specits, O chains in the LPS
  (lipopolysaccharide) called A and M
• cross-react with other smooth species but not
  with rough

6
BRUCELLOSIS

• Microbiology

Impression smear of B. abortus from aborted fetus
7
BRUCELLOSIS

• Microbiology

Impression smear of B. suis from aborted tissue
8
BRUCELLOSIS

• Pathogenecity
• Infection of non-phagocytic cells
• Mechanism of invasion not clearly understood
• Localize in rough endoplasmic reticulum
• Infection of phagocytic cells
• Invasion of PMN or MN cellsby suppression of
  bactericidal responses
• S-LPS (smooth) plays major roll in intracellular
  survival survive more effectively than rough
• low toxicity for macrophages
• low pyrogenecity

9
BRUCELLOSIS

• Pathogenecity
• Virulence
• Elimination of virulent organisms depends on
  activated macrophages and development of Th1
  cell-mediated response to antigens
• Determinants
• S-LPS is main antigen responsible for protection
• Inhibition of phagolysosome fusion
• Activation of myelo-peroxidase-halide system
• Production of tumor necrosis factor

10
BRUCELLOSIS

• Epidemiology
• Occurrence worldwide, particularly
  Mediterranean, Africa, Middle East, Latin America
• Incidence
• True incidence unknown due to underreporting
• Endemic areas gt200/100,000
• U.S. lt1/100,000
• 200 cases per year
• majority of cases from Texas, California,
  Virginia, Florida

11
BRUCELLOSIS

• Epidemiology
• Transmission
• Direct contact
• With tissues (vaginal discharge, blood, urine,
  aborted fetus)
• Ingestion
• Raw milk, milk products
• Innoculation
• Strain-19 or Rev-1 vaccine

12
BRUCELLOSIS
Epidemiology transmission
13
BRUCELLOSIS

• Disease in animals
• Primary hosts generally highly susceptible
• Varying degrees of resistance in secondary and
  aberrant hosts

14
BRUCELLOSIS
15
BRUCELLOSIS
16
BRUCELLOSIS

• Disease in humans
• Incubation period 30-60 days ( or longer)
• Signs and symptoms
• Acute or insidious onset of intermittent fever
• Accompanied by one of more of the following
• Headache
• Weakness
• Profuse sweating
• Arthralgia
• Depression
• Weight loss

17
BRUCELLOSIS

• Disease in humans
• Duration
• days to months gt year if untreated
• Complications
• osteoarticular complications (up to 60 of cases)
• genitourinary up to 20 of cases) most commonly
  orchitis and epididymitis
• Case Fatality Ratio lt2
• usually due to cardiac complications
  (endocarditis)

18
BRUCELLOSIS

• Disease in humans
• Diagnosis
• Blood culture effective in acute phase lysis
  concentration method yields best results
• allowance for slow growth
• confirmation by phage typing, oxidative
  metabolism, or genotyping
• Enzyme immunoassay (EIA, ELISA)
• IgA and IgG antibodies indication of active
  infection
• PCR antigen detection methods useful but not
  validated particularly useful for chronic disease

19
BRUCELLOSIS

• Disease in humans
• Treatment
• WHO regimen rifampin (600-900mg) and
  doxycycline (200mg) daily for at least 6 weeks
• more advanced cases require addition of an
  aminoglycoside
• Rifampin treatment of choice for children,
  followed by cotrimoxazole

20
BRUCELLOSIS

• Prevention
• Ultimately rests upon elimination or control of
  disease among domestic animals
• Hygienic measures
• Pasteurization
• Avoid ingestion of unpasteurized or untreated
  milk products
• Avoid direct contact with tissues from suspect
  animals
• Proper protective clothing by workers in
  abattoirs and other livestock operations hunters
• Immunization - small role in human population

21
BRUCELLOSIS

• Eradication efforts U.S.
• Cattle
• Currently 44 states are certified Free
• No infected herds in 12 consecutive months
• 6 are class A
• Texas, Louisiana, South Dakota, Florida,
  Missouri, Oklahoma
• Must have 12 consecutive months with no infected
  herds to achieve Free certification
• Methodtest and slaughter
• Sexually intact heifers at 4 months, bulls at 18
  months

22
BRUCELLOSIS

• Eradication efforts U.S.
• Swine
• Currently 46 states are certified Free
• 4 are class A
• TX, LA, FL, AR
• Feral swine- problem with comingling
• Control program in Texas
• If trapped, must be tested prior to relocation or
  taken to slaughter
• Hunter safety education efforts
• Meat safe if thoroughly cooked