Cornybacterial infections

CORYNEBACTERIM INFECTION (ACTINOMYCES PYOGENES)

Definiton

  • It is a common and important organism in pyogenic processes in cattle, pigs, sheep and goats

Cornybacterium

Disease

C. diphtheriae

Humans

C. renale

Pyelonephritis, ureterits, cystitis in cows; haemarrhagic cystitis and pyelonephritis in cows

C. pilosum

Cystitis and pyelonephritis in cows

C. pseudo tuberculosis
C. ovis

Caseous lymphadenitis in sheep and goats ulcerative lymphangitis and pectoral abscesses in horses

C. bovis

Pyelonephritis and cystitis in pigs

C. suis

C. pyogenes
(Actinomyces pyogenes)

Suppurative infection in cattle, sheep, ,goats and pigs;summer mastitis in cattle

C. ulcerans

Wound infections and abscess

C. equi
(Rhodoccous equi)

Pneumonia in horses

OVINE CASEOUS LYMPHADENITIS (Pseudotuberculosis of sheep & Goats)

Definition

  • Caseous lymphadenitis is a chronic disease of sheep and goats characterized by formation of abscess in lymphnodes. The disease is caused by C. pseudotuberculosis (C.ovis), a gram positive diphtheroid bacillus

Transmission

  • Way of abrasion
  • Inhalation

Pathogenesis

  • Infection through skin
  • Development of abscess in lymph nodes
  • Organisms is intracellular
  • Resistant to destruction
  • Produces exotoxin and high lipid content of bacterial cell wall which helps in survival
  • Haematogenous spread of organism
  • Abscess in many organs like lung, liver, kidney , brain , spinal cord

Clinical signs

  • Enlargement of superficial lymph nodes
  • Abscesses rupture – produces thick, green pus
  • Chronic pneumonia
  • Pyelonephritis
  • Paraplegia, ataxia

Gross lesions

  • Abscesses of lymph nodes
  • Enlargement of lymph nodes
  • A single spherical lesion
  • Upon cross section concentrically laminated
  • Layers of fibrous capsule alternate with caseous friable material which is greenish and gritty
  • In lungs, greenish to yellow pus

Microscopic lesions

  • Small focus of epithelioid cells ; Central caseous necrosis; surrounded by thin layer of fibrous connective tissue, epithelioid cells and lymphocytes
  • As lesion grow, the epithelioid and fibrous reactive layers undergo necrosis
  • New reactive layers form outside as necrosis occurs
  • A spherical, onion like concentric laminated mass is seen
  • Calcification without giant cells, seen

Diagnosis

  • Examination of pus taken for needle biopsy
  • Isolation of causative organism with diphtheroid morphology and cultural characteristics
  • Serological tests – indirect haemagglutination, hemolysis inhibition immuno diffusion, ELISA
Last modified: Wednesday, 21 March 2012, 10:47 AM