B202 - DOURINE

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B202 - DOURINE

Nature of the disease
Dourine is a venereal parasitic disease of equines due to a protozoan, Trypanosoma equiperdum. It has important economic consequences and it can be fatal.
Classification
OIE, List B disease
Susceptible species
Equines, mainly horses but donkeys and mules can also be affected.
Distribution
The disease is present in a limited number of countries in Europe, South America, Africa and Asia. It has never been recorded in the Pacific Region.
Clinical signs 
  • The incubation period varies between 1 week to a couple of months and the severity of symptoms varies according to virulence of agent and sensitivity of host.
  • First phase:
    • Fever
    • Discharge from vagina or urethra
    • Intensifying genital oedema 
    • Ulceration of oedema and secondary bacterial infection
    • Sometimes abortion
  • Second phase:
    • Urticarial plaques # 5cm in diameter and 1 cm thick, mainly on the flanks are pathognomonic
    • After a few days plaque erupt in weeping ulcers
  • Third phase :
    • Anaemia
    • Weakness
    • Laming from hind limbs
    • Ataxia
  • Death in 50% of cases in 
Post-mortem findings 
  • Emaciation, anaemia and subcutaneous oedema,
  • Oedema or depigmented scars of external genitalia
  • Enlarged lymph nodes,
  • Softening of spinal cord
Differential diagnosis 
Specimens required for diagnosis 
Parasitic identification can be attempted from genital discharges or washings and oedema fluids kept refrigerated in sterile physiological saline solutions, however parasites are difficult to observe.

Serological tests are commonly used and include Complement Fixation test (prescribed test for international trade), indirect fluorescent antibody test and ELISA. Animals present serological reaction even if they do not exhibit clinical signs of the disease.

Transmission   
Transmission is sexual but coital transmission is not systematic, lesions can be necessary. Indirect transmission by veterinary tools or biting insects is also possible.
Risk of introduction   
Dourine could be introduced through importation of live infected horses or infective semen.
Control / vaccines  
Treatment using diminazene (7mg/kg) or suramen (110mg/kg) is often successful. There is no vaccine. 

If introduced in the region systematic testing of breeding animals should be implemented.

References
  • GEERING WA, FORMAN AJ, NUNN MJ, Dourine In Exotic Diseases of Animals, Aust Gov Publishing Service, Canberra, 1995, p. 368-371
  • Dourine, In Veterinary Medicine, Saunders, Eight ed, 1997, London p. 1220-1221
  • Office International des Epizooties, 2002
  • Office Vétérinaire Fédéral Suisse