rabbit syphilis (Treponema) in Singapore, what owners should know

updated 13 May 2026 by xavier fok

rabbit syphilis (also called vent disease or treponematosis) is a bacterial infection caused by Treponema paraluiscuniculi. it’s not the same as human syphilis and can’t infect people. but it spreads between rabbits and causes characteristic crusty lesions.

it’s treatable. catching it early is the goal.

the symptoms

look for:

crusty, scabby lesions around the genitals
similar lesions on nose, lips, eyelids
lesions may bleed when disturbed
discomfort but not severe pain
otherwise healthy rabbit
may persist or progress slowly

it doesn’t typically cause systemic illness but is visually disturbing.

the cause

bacterial:

Treponema paraluiscuniculi
spread via direct contact (often during mating)
can also spread mother to kit
contagious to other rabbits
NOT contagious to humans, dogs, cats

the diagnosis

vet approach:

visual examination
darkfield microscopy of lesion scraping (gold standard)
PCR testing available in some SG labs
response to treatment (sometimes diagnostic)

the treatment

standard:

antibiotic

penicillin (specific formulations safe for rabbits)
typically penicillin G procaine + benzathine
injectable course
3 injections, one weekly
improvement visible by week 2-3

topical (sometimes)

antimicrobial wash
as adjunct, not primary

the SG vet protocol

what to expect:

diagnosis confirmation
penicillin injection course
recheck visits
treat all rabbits in household (even asymptomatic)
4-6 weeks to clearance

the contagion management

since contagious:

isolate sick rabbit during treatment
treat all in-contact rabbits
clean enclosure thoroughly
discard chewable items (toys, hay racks)
wait 2-3 weeks after clearance to confirm

the cost reality

treatment:

diagnosis: SGD 100-200
3-injection course: SGD 150-300
recheck visits: SGD 60-100 each
total typical: SGD 400-700

the prognosis

excellent with treatment:

full recovery in 4-6 weeks
no long-term effects typically
can reinfect if exposed again

the SG-specific notes

three things relevant:

1. cluster outbreaks

bonded pairs often both affected
shelter rabbits sometimes carriers
new-adoption rabbits should be checked

2. exotic vet experience

some SG vets less familiar
ask if they’ve treated treponema before
our vet directory

3. asymptomatic carriers

some rabbits have it without visible symptoms
bonded partners often test positive even if asymptomatic
treat all in contact

the differential diagnoses

other things that look similar:

skin yeast (Malassezia) — our yeast guide
mange mites
ear mites (when on face)
bacterial dermatitis
vet examination distinguishes

the bonded pair consideration

pairs:

both treated even if one asymptomatic
bond can be maintained during treatment if both isolated together
one can recover before the other
monitor both

the breeder/multi-rabbit household consideration

if breeding:

avoid breeding affected rabbits until clear
screen new acquisitions
isolate new rabbits 4-6 weeks

the rabbit-to-human safety

clear: NOT contagious to humans

handle rabbit normally (with hygiene)
wash hands after handling lesions
normal household precautions

the home care

between vet visits:

gentle cleaning of lesions
monitor for spread or new lesions
maintain rabbit’s overall health
normal diet
minimise stress

the prevention

since often sexually transmitted:

spay/neuter reduces spread
isolate breeding pairs from general population
screen new rabbits
avoid unknown rabbit contact

what owners often get wrong

three patterns:

assuming it’s just dry skin. treponema-specific treatment needed
not treating asymptomatic partners. reinfection
trying topical-only. systemic antibiotic needed

skin yeast Malassezia — looks similar
bald patches causes — other skin issues
introducing new rabbit — quarantine protocol
our vet directory — diagnosis

community-sourced information here is not veterinary advice. for any skin lesions, consult a licensed SG exotic vet for diagnosis.