July 26, 2019
A case of rabbit hemorrhagic disease (RHD) was diagnosed in a pet
rabbit in San Juan County (Orcas Island) earlier this July. Since then, a
second owner of domestic rabbits on Orcas Island reported several
deaths; samples from this premise have been shipped to the Washington
Animal Disease Diagnostic Laboratory in Pullman and results are pending.
RHD in the U.S.
In the U.S., RHD is considered a foreign animal disease. Cases in the
U.S. are sporadic, rare, and very limited in geographic distribution.
There are three major subtypes of the RHD virus: the classical form
(RHDV), its variant (RHDVa), and a recent mutation (RHDV2). The latter
is the type was identified as the causal agent in the death of the first
Orcas Island domestic rabbit. RHDV2 is much less deadly than RHDV.
However, it affects all ages of rabbits while RHDV does not seem to
affect young rabbits. All RHD viruses are highly contagious.
Signs of RHD
Signs of illness can include rapid death without prior signs of
illness. Others may display depression, poor appetite, congested eye
tissues, limpness, and lethargy secondary to fever. They may show
respiratory and/or nervous system signs as well, such as difficulty
breathing, wobbliness, prostration, paddling, and bloody nasal
discharge. Animals surviving past this stage may demonstrate signs of
liver disease that include persistent lethargy, jaundice, progressive
weight loss, and death.
The virus is shed in the
feces, urine, and nasal and oral discharges of infected rabbits. This
means the virus can enter a new host by direct contact with an infected
rabbit or indirectly through surfaces or equipment contaminated by the
excretions of infected rabbits. The virus can move from one place to
another through contaminated hands, feet, feed, water, feeding and
watering equipment, bedding, grooming tools, nest boxes, etc. Flies,
birds, and rodents are believed to play a significant role in the spread
of the RHD virus, passively picking up the virus from feces, infected
rabbits, or contaminated surfaces and transferring it to new areas and
new hosts. Rabbits allowed to free range are at even more risk:
scavengers can eat the carcasses of rabbits that have died from RHD and
move the virus to new locations by shedding it in their feces.
Prevention through Biosecurity
RHD risk to domestic rabbits can be reduced by biosecurity practices.
Preventing contact with wild rabbits and their habitat is critical;
keeping pet or farmed rabbits indoors will reduce risk significantly.
Other recommended practices include:
*On a regular basis, clean
equipment, cages, feeders, and waterers thoroughly with soap and water
and apply an effective disinfectant for the recommended contact time.
*When possible, maintain a closed colony.
*Isolate or cull sick animals promptly.
*Care for healthy animals first, then sick animals.
*Wash hands, launder clothing, and disinfect footwear after handling sick animals.
*Wash hands before and after handling rabbits and between groups of rabbits.
*Clean and disinfect footwear before entering and after leaving rabbit
housing areas; have designated farm and non-farm footwear.
Hemorrhagic Disease is not a human health concern. Control insects,
birds (including poultry), and rodents in the rabbit area.
*Do not allow visitors or insist they wear protective footwear and do not contact your rabbits.
*Quarantine any new or returning rabbits well away from the main colony for at least 30 days.
*No vaccine is currently available for use in the U.S.
RHD and 2019 Animal Exhibitions in Washington State
Exhibitors should realize and appreciate risks are always involved when
one chooses to enter animals in an exhibition. Some exhibitors decide
to only show animals at terminal shows to prevent bringing disease
agents home. Other animal owners are not willing to expose their animals
to the risk of disease and stay home. Those who choose to take breeding
animals or pets to any gathering of animals must understand the
inherent disease exposure risk involved. The common saying of “Don’t
take anything to a fair you aren’t willing to lose” is one to consider
Currently, RHD has only been diagnosed on Orcas Island
and not the Washington mainland. It is impossible to predict if the
virus will spread beyond this limited location. People need to be
vigilant and observant and report any concerns about domestic or wild
rabbit deaths to a local or state veterinarian promptly. Having
thousands of pairs of eyes in each county is the best way to identify
any new disease of concern and speed response.
Should Washington fairs cancel their rabbit shows this year?
That decision should be made locally based on the amount of risk
decision makers think RHD poses in their location. Likewise, exhibitors
can choose to accept or avoid increased disease risk by leaving their
animals home. Justifiably, San Juan County has decided to cancel the
rabbit show at its county fair in 2019. So far, the virus has not
surfaced elsewhere, so the risk is the same as always for this sporadic,
unpredictable, and highly contagious disease. Rabbits are susceptible
to several, more common diseases that can be spread at fairs.