Page 391 - The Veterinary Care of the Horse

other sites in the body, especially the joints. This can happen months or even years after the

acute phase of the disease. Many other organs may be affected.
VetBooks.ir Clinical signs

The clinical signs may include the following.

• Swollen joints.

• Stiffness or lameness in one or more limbs.
• Tender muscles.

• Poor performances.

• A temperature.

• Depression.

• Lethargy.
• Limb swelling.

• Enlarged lymph nodes.

• Inflammation of the eye; the spirochaete may cause recurrent uveitis.

• Neurological signs. Encephalitis (brain inflammation) may develop. Reported symptoms
include a head tilt, paralysis of the tail, difficulty eating, glazed eyes, profuse sweating

and aimless wandering.
• Young foals have been known to die of the disease, but this is rare.

Diagnosis

A presumptive diagnosis of Lyme disease is often made from the clinical signs and a positive

antibody titre.

However, the diagnosis is not always straightforward as the organism is difficult to
culture. Sometimes the spirochaetes can be seen in samples of blood, cerebrospinal fluid,

urine or joint fluid when they are examined under the microscope, using special techniques.
The presence of antibodies in a blood sample proves only that the animal has been

exposed to the infection at some stage of its life, not that it is the cause of the current illness.
Significant antibody levels may not be detectable in the blood early in the course of the

disease, so false negative results do occur. More than one blood sample may be required to
check the significance of any blood test results.

Treatment