Glanders

Description

Glanders is a contagious disease caused by Burkholderia (Pseudomonas) mallei. It exists in acute and chronic forms.

Signalment

Equidae are most commonly affected, horses tend to get the chronic form and mules and donkeys the acute form. The disease was once widespread in the UK but was eradicated in 1928 and is now a Notifiable disease. Distribution is limited to parts of SE Asia, The Middle East, India, North Africa, China and Mongolia.

Diagnosis

Clinical signs may be sufficient to diagnose the condition, however they do not develop until the diease is advanced therefore specific tests are indicated in suspected cases to aid prompt diagnosis.

Clinical Signs

The Mallein test is used most frquently to diagnose the condition, a fraction of the causative organism is injected intradermally into the eyelid or applied as eyedrops, a positive result is seen as local swelling and discharge 1-2 days post testing.

Laboratory Tests

Other diagnostic tests include an Elisa, complement fixation and culture of the orgamism from exudative lesions.

Treatment

There is no vaccine available. Prevention and control focuses on prompt detection and slaughter of infected animals and complete quarantine and disinfection of the affected premises.

Prognosis

prognosis is poor, the diease is usually fatal. Animalss which survive should be slaughtered to prevent spread of the disease.

References

• Characterised by multiple small submucosal nasal nodules which liquefy and ulcerate
  • Cores of neutrophils surrounded by a rim of macrophages and granulation tissue
• In addition may have similar nodules in lungs, lymph nodes and cutaneous lymphatics
• Clinical signs: fever and head/ neck lymphadenitis, rhinitis

• Pathogenesis:
  • Transmited by ingestion of food/water contaminated by nasal discharge of infected Equidae; occasionally via inhalation or skin wounds
  • Organism invades nasopharyngeal mucosa and spreads to other tissues via lymphatics
  • Presence of B. mallei in host causes hypersensitivity reaction
• Clinical infections:
  • Acute septicaemic form with fever, mucopurulent nasal discharge and respiratory signs; death within weeks
  • Chronic disease more common:
    • Nasal form: rhinitis; ulcerative nodules develop on mucosa of nasal septum and lower part of turbinates; purulent blood-stained nasal discharge; regional lymphadenitis
    • Respiratory form: respiratory distress; granulomatous lesions throughout lungs
    • Cutaneous form (farcy): lymphangitis; nodules along lymphatic vesselsof limbs; ulcers develop and discharge pus
    • May die after several months or recover and shed organisms from respiratory tract or skin
  • Carnivores may contract disease by eating infected carcasses
• Diagnosis:
  • Grows on media containing 1% glycerol; most strains are non-lactose fermenters on MacConkey agar
  • Complement fixation and agglutination
  • Serology