Page 593 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

568 CHAPTER 2

VetBooks.ir penile and preputial skin, the urethral fossa and the EQUINE COITAL EXANTHEMA
diverticulum following sodium hypochlorite wash-
ing (5.25%). (Note: Gentamicin ointment is no Definition/overview
longer available for veterinary use in Europe.) In This is a self-limiting venereal disease affecting
persistent cases, a gentamicin-impregnated surgi- mares (p. 493) and stallions. It has a worldwide
cal sponge can be cut to size and inserted into the distribution.
urethral fossa and diverticulum and left in place for
up to 7 days. This can be successful in eliminat- Aetiology/pathophysiology
ing infection, but often causes local reaction and Equine coital exanthema is a highly contagious dis-
soreness. ease caused by EHV-3 and spread through coitus or
In Pseudomonas infections, after washing and contaminated veterinary equipment.
removal of smegma, some success has been reported
with the use of a 1% silver nitrate solution spray Clinical presentation
daily for up to 30 days. Periodic treatment with ster- Symptoms develop 4–8 days after infection, with
ile petroleum jelly will help to prevent the penile 2-mm diameter red nodules appearing on the penis
skin from cracking during treatment. and preputial skin. These develop into vesicles and
Thorough disinfection is required to prevent then pustules, which rupture, leaving shallow ero-
colonisation of equipment including buckets and sions (Fig. 2.164). Fertility is not usually impaired,
artificial vaginas. Infected stallions should have ded- but stallions are reluctant to copulate due to pain.
icated equipment to prevent pathogen transmission The course of uncomplicated infection is 3–4
to other stallions. Periodic repeat cultures should be weeks. Secondary bacterial infection of the lesions
conducted to monitor these infections. Stallions can may occur. Unpigmented scars remain visible after
be managed in some cases by minimum contamina- recovery.
tion breeding techniques and incubating semen in
an extender containing the appropriate antibiotic for Differential diagnosis
at least 1 hour prior to insemination. Trauma; contact sensitivity; bacterial infection.
After antiseptic washing or antibiotic treatment,
the penis and prepuce may be treated with a specifi- Diagnosis
cally cultured active broth containing a mixture of History and clinical signs are suggestive of EHV-3
microflora from normal equine external genitalia infection.
to try to encourage rapid recolonisation with nor-
mal flora and prevent overgrowth with pathogenic
bacteria. 2.164
Progress should be monitored by follow-up swab
samples collected every 2 days from the urethra, ure-
thral fossa and diverticulum, and preputial smegma
7 days after the end of treatment. Three sets of neg-
ative swabs can be assumed to indicate successful
treatment.

Prognosis
The prognosis is good for treating colonisation of the
external genitalia, but much worse when infection
involves the accessory sex glands, which frequently
requires long and repeated treatment programmes.
Some stallions are never successfully cleared of the
infection. Fig. 2.164 Acute coital exanthema ulcerative lesions
on the glands of the penis of a stallion.