A look at tick diseases in horses
KINGSTON, Jamaica - With 2019 Triple Crown winner Supreme Soul spending the last three months in quarantine receiving treatment for tick fever.
Below is a closer look at tick diseases in horses.
QUICK FACTS
Ticks can transfer many disease-causing organisms to horses. Horse owners should be aware of two of the most common tick diseases:
- Piroplasmosis
- Lyme disease
PIROPLASMOSIS
Piroplasmosis is caused by two protozoan parasites and is the most common tick-transferred disease to cause illness in horses. While tick fever can be life-threatening, if untreated, many horses are asymptomatic carriers. Horses that suffer chronic disease may show reduced tolerance for exercise. Humans and other animal species, including dogs and livestock, can get a similar illness from ticks.
SIGNS OF ILLNESS
In horses, signs of illness usually appear 5 to 45 days after infection. Limb swelling, weakness, lack of appetite, yellowing of the mucous membranes, and small bleeds (nose, vulva) sometimes accompany fever.
Less common signs include incoordination, muscle swelling, or gut pain (colic).
Clinical signs set the base for diagnosis in horses with possible tick exposure during warm weather. Your veterinarian may confirm the diagnosis by blood analysis.
TREATMENT
Antibiotic/Antiprotozoal treatment is usually useful if you treat the horse shortly after the signs of illness begin. Treatment is generally over a 5-12-day period depending on the severity of disease and type of protozoan parasite involved.
Treatment is not without side effects, notably colic-type signs, diarrhoea, sweating, and restlessness. Relapses may occur if treatment is too short. Other supportive care often used include nonsteroidal anti-inflammatory drugs and leg support wraps.
LYME DISEASE
Borrelia burgdorferi is the organism that causes Lyme disease and is a much less frequent source of illness in horses.
Lyme disease has not yet been diagnosed in horses in Jamaica. Tick bites expose horses to this organism. Few horses develop the clinical illness, usually months after the bite.
DIAGNOSING
Possible diagnosis of Lyme disease often occurs after ruling out the more common causes of:
- Lameness
- Joint swelling
- Incoordination
Your veterinarian will likely take two blood samples two to three weeks apart to check for any changes that show a sign of active infection. Your veterinarian can also diagnose the disease after taking a tissue sample from an affected joint or lymph node.
TREATMENT
If your veterinarian finds evidence of Lyme disease, they may try the similar treatment as used for piroplasmosis to see if this improves your horse’s signs of illness.
PREVENTING TICK DISEASE
There are no vaccines available for piroplasmosis or Lyme disease, but there are prevention steps you can take.
- Remove and destroy ticks as soon as possible.
- Check horses for early signs of illness.
- Reduce tick habitat near horses.
- Clear the brush out of pastures and along both sides of the fence line.
- Keep pastures mowed.
- Use a topical insecticide that includes a label claim for ticks. Apply it to your horse before riding through long grass or brush.
Importantly, tick fever organisms can be transmitted inadvertently through contaminated blood via reuse of needles and syringes; improperly sanitised surgical, dental or tattooing instruments; and blood transfusions. It is therefore important to ensure that proper precautions are taken in preventing inadvertent transmission.
