CASEOUS LYMPHADENITIS

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Causative Agent(s)

It is caused by Corynebacterium pseudotuberculosis, a small Gram-positive rod. It is a facultative intracellular parasite found on fomites, soil, and manure contaminated with pus.

Clinical Presentation and Epidemiology

Initial infection may cause no clinical signs or may be accompanied by high fever, anorexia, anaemia, and cellulitis at the infection site. Superficial abscesses enlarge and may rupture and discharge infectious materials. Superficial abscess develops at the prescapular and pre-femoral regions in sheep on range whereas in housed animals, abscesses occur more commonly at the head and neck region suggesting transmission by contaminated feed, feeders, or other fomites. Animal with superficial abscesses show no apparent signs of sickness except when the location of the abscess interferes with functions such as swallowing or breathing. In the visceral form of the disease, pulmonary, hepatic, and renal abscesses commonly cause “thin ewe syndrome”; other manifestations include caseous bronchopneumonia, arthritis, and abortion.

Diagnostic Considerations
  • Bacterial culture of purulent material from an intact abscess
  • Radiography and ultrasonography can be useful to detect internal
  • Serologic testing Management and Treatment External form:

Prior to abscess, isolate the affected animal, lance the abscess, flush the abscess cavity with an antiseptic solution (iodine solution), and pack the cavity with gauze.

Surgical removal of infected lymph nodes is another treatment option Internal form:

Long-term antibiotic treatment.

Long-term administration of procaine penicillin G, Penicillin G benzathine, Pen-Strep, Tulathromycin

  • Penicillin G benzathine 2 million IU/kg IM
  • Pen-Strep (Penicillin 2,000,000 IU - streptomycin 5g) 1mg/5kg IM
  • One dose of tulathromycin at 2.5 mg/kg, either SC directly into the abscess cavity, or two doses at 5 mg/kg, administered at the same time, one SC and one intra-lesionally, can resolve the lesions without lancing the abscess.
  • Strict biosecurity measures and elimination of diseased animals from the herd/flock is of great importance in the control of caseous lymphadenitis.

Control

  • Vaccination - Commercial CL vaccines are currently licensed for use in sheep and These vaccines should only be used in the species they are labelled for, because adverse reactions have been reported in goats given vaccine labelled for sheep
  • Disinfection of shearing equipment and other instruments used for production procedures (castration, ear tagging, etc) between animals is highly advised.
  • Removal of hazards in the environment that could potentially injure the skin
  • Pre-purchase examination for lesions, serologic screening, and a period of quarantine before introduction of new animals.