Leptospirosis is a zoonotic disease affecting humans as well as farm animals including cattle, horses, sheep and dogs. The disease is caused by infection with Leptospira
bacteria. L. interrogans
is the species predominately isolated from infected horses. Leptospirosis has been linked to equine recurrent uveitis
in the Southern United States. Investigations in the U.S. implicated leptospirosis in 3% of abortions in mares. Sporadic cases of leptospirosis have occurred in horses in Australia. The disease is not nationally notifiable.
How Leptospirosis is Spread
Leptospirosis is spread predominately through ingestion of or contaminated of cuts and abrasions with the urine from infected animals. Many different species of wildlife, including rats, can become infected and serve as a common source of the disease. Horses are more likely to get infected through ingestion or contact with slow-moving or stagnant water sources that are contaminated with urine from infected animals. Horses with access to swampy areas, flooded areas of pasture, or ponds are more at risk.
The incubation period is 2–20 days. Abortion or stillbirth usually occurs in pregnant mares from 6 months of gestation to term.