Equine serum hepatitis (i.e., Theiler's disease or idiopathic acute hepatitis) is a serious and often life-threatening disease of horses that was first described in 1919 in South Africa by Sir Arnold Theiler.
After the horse died of Theiler's disease in January 2014, serum and liver samples were collected and frozen or kept on ice before being shipped from the clinic of origin to Cornell University (Ithaca, NY, USA) for viral diagnostic testing.
These sample lots were selected because they had been reported to us to have been associated with additional cases of Theiler's disease. We pooled both lots for inoculation so that each horse received the identical inoculum.
Identification of EqPV-H in Horse with Theiler's Disease
Complete recovery of both horses in the experimental study was not surprising because rapid (3-7 days) recovery occurs in some horses with Theiler's disease (5,8).
This finding would be compatible with epidemiologic data on Theiler's disease outbreaks in which clinical hepatitis develops in only 1.4%-2.2% of horses receiving equine blood products (1,2).