During the past two foaling seasons (through February 20, 2001), 39 cases of leptospira-induced abortion or neonatal death have been diagnosed at the Livestock Disease Diagnostic Center. Five cases occurred during the 2000 season and 34 during the 2001 foaling season.

Equine Recurrent Uveitis (ERU), the most common cause of blindness in horses and mules, is an immune-mediated disease. ERU is also called moon blindness because historically its recurrence was thought to be related with the phases of the moon. It is believed to have many different causes, such as bacterial, parasitic, trauma, viral, or immune disorders.

From time-to-time, horse owners and veterinarians see equine recurrent uveitis, also known as periodic ophthalmia or moon blindness, in horses. Horse owners will see this as a painful eye. Painful eyes result from either damage or disease to the cornea or to the uvea (iris, ciliary body and choroid).

Techniques were developed to use immunohistochemistry to demonstrate the expression of individual leptospiral antigens in the tissues of experimentally infected hamsters. It was demonstrated that certain antigens which are expressed in abundance in vitro are not expressed on organisms in vivo.