Recognising Lyme disease in horses

Lyme disease, also known as borreliosis, is an infectious disease that affects both humans and animals, particularly horses. Although non-contagious, this tick-borne vector-borne infection can cause a range of symptoms in equines, from fever to neurological damage. In this article, we will explore the causes, symptoms, diagnosis and treatment of Lyme disease in horses, as well as prevention methods to protect your horse from this infection.

What causes this disease?

Borreliosis, or Lyme disease, is an infection caused by the bacterium Borrelia burgdorferi, transmitted by tick bites. This bacterium belongs to a family of spirochetes and has been identified in 11 subspecies, several of which can infect horses. The main vector of the disease is the tick of the genus Ixodes, and in Europe the tick most often implicated isIxodes ricinus. This tick lives in damp, forested areas, where it waits to find a host to parasitise, such as a horse.

Lyme disease was first described in the United States, but is now widespread in Europe. Horses can contract Lyme disease by being bitten by an infected tick, but transmission is not immediate. It is essential to note that this disease is not contagious between horses. Animals carrying the bacterium cannot transmit it directly to other animals through contact.

In addition to ticks, other insects such as fleas, mosquitoes and horseflies can also be vectors of this disease, although ticks remain the main transmitters. Borreliosis is a zoonosis that affects not only animals but also humans, making it a major public and veterinary health concern.

What are the symptoms of Lyme disease in horses?

The symptoms of Lyme disease in horses vary widely and are often not very specific, making diagnosis difficult. The interval betweeninfection and the first clinical signs remains uncertain, but horses sometimes display vague symptoms, easily confused with other diseases.

Affected horses may present with fever, lethargy, anorexia and chronic wasting. Some horses may develop more serious signs such as joint pain (arthritis), stiffness or sporadic lameness. Swollen joints and eye problems such as uveitis are not uncommon . These eye inflammations can sometimes lead to loss of vision if they are not treated quickly.

Neurological symptoms, although rare, can also occur. Horses may show signs of neck stiffness, muscle atrophy or even reduced motor coordination (ataxia). In the most serious cases, peripheral nervous disorders such as a loss of anal tone may be observed.

It is also possible for the disease to manifest itself asymptomatically. In some experimental infections, horses have shown signs of contact with the bacteria without developing any visible symptoms. This makes early detection of Lyme disease all the more complicated.

How is it diagnosed?

Diagnosis of Lyme disease in horses is complex and relies mainly on laboratory tests. Given the limited number of studies available, it is often difficult to obtain a definitive diagnosis. Diagnostic methods include serological tests and molecular biology analyses.

Serology is used to detect the horse’s immune response to infection. Common tests includeIFI (indirect immunofluorescence),ELISA (enzyme-linked immunosorbent assay) and Western blot, which detect the presence ofspecific antibodies to Borrelia. However, these tests may not be entirely reliable, as a horse can be a carrier of the bacteria without developing clinical symptoms.

Molecular biology tests, such as PCR (polymerase chain reaction), aim to detect the DNA of the bacteria directly in the horse’s blood or tissues. Although PCR can provide more accurate results, it is not always effective, as the bacteria are not always present in large quantities in the blood.

The ELISA and Western Blot tests are the most widely used in veterinary practice. The ELISA test is used to quantify the antibodies present against Borrelia, while the Western Blot provides a more specific confirmation of the results. The PCR test, although sometimes less conclusive in equine species, can be useful for detecting the bacteria in specific tissues such as synovial fluid or cerebrospinal fluid.

What treatments are available?

Treatment of Lyme disease in horses is mainly based on the use ofantibiotics. The bacterium that causes the disease requires prolonged antibiotic treatment in order to eliminate theinfection. However, the choice of treatment and its duration vary according to the severity of the symptoms and the horse’s general state of health.

Tetracyclines and beta-lactams are the most commonly prescribed antibiotics for horses with Lyme disease. Doxycycline, administered orally, andoxytetracycline, administered intravenously, are frequently used. These drugs help to inhibit the multiplication of the bacteria and reduce the inflammation associated with the infection.

Strictly adhere to the doses prescribed by your vet to avoid incomplete or incorrect treatment. The latter could lead to severe side-effects, including digestive problems. In serious cases, where neurological or joint damage is present, a longer course of treatment may be necessary.

Veterinarians prescribe non-steroidal anti-inflammatory drugs to relieve pain andinflammation. In cases ofuveitis, they use mydriatic eye drops and corticosteroids to protect the eyes and reduceinflammation.

What are the natural alternatives?

Conventional treatments are enhanced by theuse of medicinal plants, which speed up the recovery from Lyme disease in horses. Among these, Cardera stands out for its powerful antibacterial properties against spirochetes such as Borrelia burgdorferi.

Chard also has anti-inflammatory properties and helps to detoxify the body by supporting organs such as the liver and kidneys. This plant effectively relieves joint pain and strengthens the immune system, essential support for horses suffering from Lyme disease.

Other plants, such as Milk Thistle, rich in silybin, offer a powerful hepatoprotective effect. They help protect the liver from the toxins released by the bacteria. Rosemary and Desmodium are also plants renowned for their detoxifying and liver-stimulating properties.

Savory, for its part, is a powerful natural antibacterial, useful in combating the secondary infections that can occur in cases of chronic Lyme disease.

What can be done to prevent Lyme disease?

Unfortunately, there is currently no vaccine available against borreliosis in horses. Prevention is therefore based on measures to reduce exposure to ticks. This includes treating pastures to eliminate tick-friendly habitats and checking horses daily for ticks.

It is advisable to avoid walking horses through tick-infested woodland during the summer months. Anti-tick products can also be applied to horses before outings to reduce the risk of biting.

Finally, regular and careful grooming means that ticks can be detected early and removed before they transmit the disease. Prevention focuses above all on reducing tick-friendly habitats and encourages theuse of suitable products to protect horses.