Occurrence of equine coital exanthema in pastured draft horses and isolation of equine herpesvirus 3 from progenital lesions.

The study investigates an outbreak of equine coital exanthema (ECE), a horse reproductive disease, in draft horses pastured in Iwate Prefecture, Japan, from 2001 to 2002. The research found that this disease seemed to be transmitted through coitus and could be linked to the detection of the Equine herpesvirus 3 (EHV3) within the affected horses.

Context of the Study

• The research was triggered by the occurrence of progenital diseases in draft stallions and mares pastured together in Iwate Prefecture, Japan, from 2001 to 2002.
• Several horses were affected each year, with various clinical symptoms including papules, pustules, ulcers, and scabs observed on the progenital skin and mucosa.

Key Findings

• In 2002, the Equine herpesvirus 3 (EHV3) was isolated from two mares and detected genetically in one stallion and four mares using Polymerase Chain Reaction (PCR), indicating a possible infectious agent behind the disease.
• Serum neutralizing tests revealed that out of 38 horses, 12 turned positive for EHV3 antibodies, indicating a recent or prior infection.
• The results suggested that the horses contracted equine coital exanthema (ECE), a disease caused by EHV3, through coitus or sexual mating.

Possible Origins and Prevention

• The researchers suggested that the original sources of the EHV3 infection in 2002 might have been the five mares that had the EHV3 antibodies before the pastured period. The exact origin of the disease in 2001, however, remained unknown.
• To prevent the further spread of ECE, artificial insemination was introduced to the pastured horses in 2003. This appeared to be effective as no disease outbreak was reported in this year.
• However, the researchers noted an increase in antibody titers in three mares previously tested positive for EHV3, suggesting that these mares still had the potential to spread the virus in future breeding seasons.

The study highlighted the need for further research and implementation of preventive measures, specifically artificial insemination, to control the spread of ECE in horse populations.