effects of lyme disease in horses
1 The horse will occasionally show signsof eye pain. 2  Sporadically, the disease can affect the horseâs brain, causing behavioural changes, paralysis and other nervous disorders.  The disease is rarely fatal, except occasionally in foals, but it can cause long-term effects in horses with arthritis or brain problems. Finding antibodies. A diagnostic aid is to analyse a blood sample for specific antibodies (special blood markers) to the bacteria which cause Lyme disease.