Horses are exposed to ticks throughout their daily lives; tick checks are a must.
As the tick population increases in Canada, it stands to reason that ticks are becoming an increasingly significant parasite of horses. In many areas of the country where they have not occurred before, they are now commonplace. The reason for the increase is undecided. Some say it’s because our temperatures are warming up, others say it’s the increase in wildlife populations. It could be either, or, most likely both. However, a female tick will lay 1500-3000 eggs at a time. So it stands to reason that the tick population is bound to explode if the environment is right.
Ticks are known to carry and transmit up to 18 different pathogens. While Lyme disease seems to be the most known and talked about tick-borne disease in the general population, it isn’t the only one you need to look out for.
The two most common tick-transferred diseases found in horses are Anaplasmosis and Lyme.
WHERE TICKS ARE FOUND
Ticks are typically found in wooded areas, forests, tall grass, shrubs, and leaf litter. They prefer shady and moist areas usually around ground level. When looking for a blood meal, ticks will generally cling to tall grass and low shrubs with their front arms (legs) out, ready to latch on to their next victim.
HOW TICKS ATTACH
Ticks do not hunt with eyes or ears, they have strong smelling organs (Haller's organs found on their two front legs) that are used to find their hosts by detecting the ammonia given off by the host's breath and body during sweating, or by sensing heat, moisture, and vibrations. They wait for a host while resting on the tips of grasses and shrubs with their first pair of legs outstretched. When the horse brushes by, the tick will quickly climb aboard. Some ticks attach immediately while others move around the horse’s body, looking for areas where the skin is thinner. That’s why ticks are most often found on a horse’s chest, underbelly, mane, tail, or inside their flank. The result is often a local skin reaction that appears as a small, firm nodule.
Once filled with blood, ticks drop off to molt and progress to the next stage of their life cycle or in the case of adult females, lay eggs.
ANAPLASMOSIS
Anaplasmosis, while treatable if caught on time, can be a serious and sometimes fatal disease. It is caused by the bacterium Anaplasma phagocytophilum. The black-legged tick and Western Blacklegged tick are the primary transmitters of this bacterium. Also known as equine granulocytic anaplasmosis (EGA) or equine anaplasmosis, this disease is relatively new, first described in the United States in 1969 but now increasingly recognised both in the US and Europe.
Symptoms
Symptoms can vary depending on the age of the horse. They present as follows:
Horses < 1 year old: fever only
Horses 1-3:
fever
depression
mild limb swelling
lack of coordination.
Adult Horses:
fever,
poor appetite,
depression,
reluctance to move,
limb swelling, and
jaundice.
“Fever is highest during the first 1 to 3 days of infection, but may last for 6 to 12 days. Signs become more severe over several days. Any existing infection (such as a leg wound or respiratory infection) can be made worse. The infectious agent can be found in white blood cells 3-5 days after infection. DNA and antibody tests can also detect the disease.” - Merck Vet Manual
Treatment
Antibiotics (tetracycline or doxycycline) may be prescribed an anti-inflammatory (phenylbutazone or Banamine) medications. Horses usually feel better within 24 hours after the start of treatment. It is important to follow the veterinarian’s treatment plan, to ensure that the anaplasmosis has been eradicated from the horse’s bloodstream. In rare cases, horses recovering from anaplasmosis may suffer a relapse.
LYME DISEASE
Caused by the spirochete bacterium Borrelia burgdorferi, Lyme disease is transferred to horses via infected ticks, the most common one being the black-legged tick. Unfortunately due to the very mysterious and vague nature of the disease (not only in horses), it can be very difficult to diagnose and recognise. It is also possible that the horse can get bit and never develop clinical signs or exhibit them at a much later date after the tick has bitten and infected the horse.
Symptoms
Symptoms may present as some, all, or none of the following:
A swollen lump at the site of the tick bite
Low-grade fever
Swollen joints
Uveitis (eye inflammation)
Stiffness
Sporadic lameness
Shifting leg lameness
Lethargy
Muscle tenderness
Neuroborreliosis: A rare but very serious form of Lyme. This is when the bacteria invades the horse’s central nervous system, causing severe issues including
Hyperesthesia: increased sensitivity of any of your senses, such as sight, sound, touch, and smell.
Ataxia: abnormal foot placement or lack of coordination in foot placement
Dysphagia: difficulty swallowing
laryngeal dysfunction, Increased panting and/or harsh-sounding breathing, particularly when panting.
Cranial nerve deficits: mental activity, head posture and coordination, and reflexes on the head
Muscle atrophy: When a muscle of a horse decreases in size, seemingly melting away. and
Neck stiffness
Fever
Neuroborreliosis can be fatal.
Treatment
If caught in the early stages, the most common, non-neurologic forms of Lyme disease are very treatable using antibiotics such as intravenous oxytetracycline or oral doxycycline.
PREVENTION
There is no vaccine to prevent Anaplasmosis or Lyme disease, so the best defense is to be proactive in your protection regime.
Start with the horse’s environment to make it as uninviting to ticks as possible. This includes mowing pastures and removing brush, debris, and other places ticks like to lurk.
By removing the wooded areas and low-lying brush, weeds, and debris in your pastures, where ticks like to live and breed, you can reduce the tick populations that your horse is exposed to.
Regularly apply a proven tick repellent spray on the horse's coat.
Groom your horse often and do tick checks. Removing ticks as soon as or very shortly after they have attached will reduce their likelihood of contracting tick-borne diseases. Make sure you run your hands over all of your horse's body including the tail, tail-head, and ears
If you do find a tick make sure you remove it properly. Squeezing the tick can force it to regurgitate into your house increasing the potential risk of infection.
While it may seem cumbersome to apply these steps to your routine it is a lot less of a hassle and less expensive than having to treat one of these diseases.
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