ARCHIVE: Dourine
If you suspect signs of any notifiable disease, you must immediately notify a Defra Divisional Veterinary Manager.
Dourine is a contagious disease of horses transmitted only by coitus and characterised by inflammation of the external genital areas, skin lesions and paralysis. The causal agent is a trypanosome - Trypanosoma equiperdum - which is incapable of living outside the horse and dies quickly in the carcase.
Dourine is enzootic in Africa, Asia, South eastern Europe, South America and in a small area of the Southern United States of America. The disease has never occurred in this country.
Mortality rate: In Europe this may be as high as 50 to 75% but in the enzootic areas a milder form of the disease exists with much lower mortality figures. Many chronically affected animals may have to be destroyed. Incubation period: This varies from between one to four weeks and infection occurs only by coitus and may be transmitted from stallion to mare or vice versa.
Clinical signs
These vary in severity depending on the strain of trypanosome and the general health of the horse. Malnutrition and intercurrent disease conditions may exacerbate the symptoms.
In stallions the initial signs are swelling and oedema of the penis, scrotum and prepuce and surrounding skin which may extend as far forward as the chest. There is a mucourulent urethral discharge. In mares there is oedema of the vulva with a profuse fluid discharge and sometimes ulceration of the vagina. The oedema extends to the perineum, udder and along the abdominal floor.
Nervous signs appear at a variable time following the genital involvement. These nervous signs are stiffness and weakness of the limbs with inco-ordination and general loss of condition. Atrophy of the hindquarters with extreme emaciation may necessitate destruction of the animal.
In Europe, symptoms are most severe with sexual excitement and the appearance of ulticaria-like plaques 2 to 5 centimetres in diameter along the boy and neck. These persist from a few hours up to a few days and succeeding crops of plaques may occur for several weeks.
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Page last modified: September 9, 2009