Introduction

EXERCISE-9: BRUCELLOSIS

  • Brucellosis is one of the major bacterial zoonosis. In humans, the disease is known as ‘Undulant fever’, ‘Malta fever’ or ‘Mediterranean fever’.
  • It is transmitted directly or indirectly from animals by contact.
  • The disease is endemic where the cattle, pigs, goats and sheep are raised in large numbers.
  • It is caused by Brucella melitensis, B.abortus, B.suis and B.canis.
  • The bacteria is small, Gram negative, rod-shaped, non-motile, non-sporing and intracellular.
  • They are arranged in singles, pairs, in short chains and in groups.
  • The diagnostics available at Institute of Veterinary Preventive Medicine, Ranipet and Indian Veterinary Research Institute, Bareilly.

Host range and clinical significance in man

Brucella spp

Host and clinical significance

Species occasionally infected and clinical significance

B.melitensis

Goats and sheep: Abortion, orchitis, arthritis

  • Cattle: Sporadic abortion
  • Humans: Undulant fever, Malta fever or Mediterranean fever

B.abortus

Cattle: Abortion, orchitis

  • Sheep, goats and pigs: Sporadic abortion
  • Horse: Bursitis
  • Human: Intermittent fever, systemic disease

B.suis

Pigs: Abortion, orchitis, arthritis, spondylitis, infertility

Humans: Intermittent fever, systemic disease

B.canis

Dogs: Abortion, epididymitis, spondylitis, sterility in male dogs

Human: Mild systemic disease

Tests used in the diagnosis of brucellosis using milk or serum

Test

Comment

Brucella milk ring test

  • Conducted on bulk milk samples for monitoring infections in dairy herds.
  • Sensitive but may not be reliable in large erds.

Rose-Bengal plate test

  • Useful screening test.
  • Qualitative test only.
  • Positive results require confirmation by CFT or ELISA.

Compliment fixation test (CFT)

  • Widely accepted confirmatory test for individual animals.

Indirect ELISA

  • Reliable screening and confirmatory test.

Serum agglutination test (SAT)

  • Tube agglutination test which lack specificity and sensitivity.
  • IgG1 antibodies may not be detected, leading to false negative.

Antiglobulin test (Coomb’s test)

  • Sensitive test for detecting non-agglutinating antibodies not detected by the SAT.

Skin test (Brucellin test)

  • Similar to tuberculin test.

Last modified: Wednesday, 16 May 2012, 6:26 AM