Pathogen test
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The PCR test detects the genome (DNA) of Trypanosoma equiperdum, the pathogen responsible for Dourine.
Sample
- 5 mL - blood - K3 EDTA tube
Turnaround time
- 2 to 5 working days
What is Dourine?
- Dourine is a chronic or acute contagious disease of breeding equids that is transmitted directly from animal to animal during coitus. The causal organism is Trypanosoma equiperdum.
- Dourine is the only trypanosomosis that is not transmitted by an invertebrate vector.
- Trypanosoma equiperdum differs from other trypanosomes in that it is primarily a tissue parasite that is rarely detected in the blood. There is no known natural reservoir of the parasite other than infected equids.
Clinical signs
- Dourine is characterised mainly by swelling of the genitalia, cutaneous plaques and neurological signsThe symptoms vary with the virulence of the strain, the nutritional status of the horse, and stress factors.
- The clinical signs often develop over weeks or months.
- They frequently wax and wane; relapses may be precipitated by stress. This can occur several times before the animal either dies or experiences an apparent recovery.Genital edema and a mucopurulent discharge are often the first signs.
- Mares develop a mucopurulent vaginal discharge, and the vulva becomes oedematous;
- The genital region, perineum and udder may become depigmented.
- Abortion can occur with more virulent strains.
- Stallions develop edema of the prepuce and glans penis, and can have a mucopurulent discharge from the urethra.
- In stallions, the swelling may spread to the scrotum, perineum, ventral abdomen and thorax.
- Neurological signs can develop soon after the genital edema, or weeks to months later.
- Restlessness and weight shifting from one leg to another is often followed by progressive weakness, incoordination and, eventually, paralysis.
- Facial paralysis, which is generally unilateral, may be seen in some animals.
- Conjunctivitis and keratitis are common, and in some infected herds, ocular disease may be the first sign of dourine.
- Anemia and intermittent fever may also be found.
- In addition, dourine results in a progressive loss of condition, predisposing animals to other diseases.
Transmission
- Unlike other trypanosomal infections, dourine is transmitted almost exclusively during breeding.
- Transmission from stallions to mares is more common, but mares can also transmit the disease to stallions.
- T. equiperdum can be found in the vaginal secretions of infected mares and the seminal fluid, mucous exudate of the penis, and sheath of stallions.
- Periodically, the parasites disappear from the genital tract and the animal becomes noninfectious for weeks to months.
- Non infectious periods are more common late in the disease. Male donkeys can be asymptomatic carriers.
- Rarely, infected mares pass the infection to their foals, possibly before birth or through the milk.
- Infections are also thought to occur through mucous membranes such as the conjunctiva.
- Other means of transmission may also be possible; however, there is currently no evidence that arthropod vectors play any role in transmission.
- Sexually immature animals that become infected can transmit the organism when they mature.
Prevention
- To prevent dourine from being introduced into a herd or region, new animals should be quarantined and tested by serology.
- When dourine is found in an area, quarantines and the cessation of breeding can prevent transmission while infected animals are identified.
- Dourine can be eradicated from a herd, using serology to identify infected equids.
- Infected animals are euthanised.
- In some cases, stallions have been castrated to prevent disease transmission; however, geldings can still transmit the disease if they display copulatory behavior.
- Successful treatment with trypanocidal drugs has been reported in some endemic areas.
- However, therapeutic regimes have not been thoroughly investigated, and treatment is usually discouraged due to fears that the organism will persist inapparently.
- Good hygiene should be used at assisted matings. No vaccine is available.