- EHV-3 is
the causative agent of equine coital exanthema, a benign venereal
horses that affects both sexes.
- EHV-3 is probably present worldwide. In one
study, 27% of tested stallions showed evidence of previous infection
- EHV-3 is
transmitted primarily through venereal contact, although it also has
ability to spread by fomites such as shared rectal sleeves, and other
- The reservoir for EHV-3 is most likely mares in a
latent state of the infection. The virus is then transmitted to the
during breeding, and then the stallion will transmit the virus to all
females that he subsequently breeds before the clinical signs appear.
immunity is provided by the initial infection, although re-infection
breeding season is still possible.
- Equine coital exanthema causes disease
in both mares and stallions, and the lesions are mild, transient,
self-limiting, and may be recurrent. The lesions are small papules that
progress to pustules, then abscesses. These lesions are found on the
perineum of mares, and on the penis and prepuce of stallions.
- The disease is
not known to spread systemically in mares, but has rarely been shown to
in stallions, causing dullness, anorexia, and fever. Normally, the
confined to the genitals of affected individuals, with spontaneous
within 14 days. As the lesions heal, the affected areas will be left as
fertility of horses infected with equine coital exanthema is not
However, the libido of stallions with clinical disease may be reduced
of the painfulness of the lesions on the genitals
no specific treatment
for equine coital exanthema, and will usually heal on its own after
days. Secondary bacterial infections may be established, in which case
appropriate antibiotic therapy is indicated.
- There is no vaccine available
for the prevention of equine coital exanthema, so hygienic measures are
only way to control the spread of the disease.
- Any animals with lesions
associated with equine coital exanthema (male or female) should be
from natural breeding until the lesions have completely healed.
infected stallion and then breeding AI may reduce the risk of EHV-3
transmission, although it is still possible that transmission may
occur. It is
also important to prevent the iatrogenic (unintentional transmission by
humans) spread of the virus through
rectal sleeves or other contaminated water or veterinary/artificial