Rabbit Vaccination Against RHDV

Rabbit Haemorrhagic Disease Virus is a highly contagious calicivirus capable of killing an apparently healthy rabbit within a day or two of exposure, and vaccination remains the only reliable protection available, since there is no specific antiviral treatment once clinical disease develops. Both RHDV1 and the more recently emerged RHDV2 strain circulate in wild rabbit populations in many regions, making even indoor-only pet rabbits at some risk via insects or fomites.

How RHDV Kills So Quickly

RHDV replicates primarily in the liver, causing massive hepatocyte necrosis that triggers disseminated intravascular coagulation, a catastrophic clotting cascade that leads to widespread internal haemorrhage. This explains the disease's hallmark presentation: rabbits are frequently found dead with no preceding signs, or with only brief lethargy and blood-tinged nasal discharge in the hours before death.

RHDV2, first identified around 2010, differs enough antigenically from classic RHDV1 that immunity to one does not reliably protect against the other, and RHDV2 also affects young rabbits and species such as hares that RHDV1 spared, which is why current vaccination protocols in affected regions specifically require protection against both strains rather than assuming cross-immunity.

RHDV1 Versus RHDV2 and Why Both Matter

• Sudden death with no preceding illness observed by the owner
• Brief lethargy, inappetence or fever in the hours before death
• Blood-tinged discharge from the nose in the terminal stage
• Neurological signs such as paddling or vocalisation just before collapse
• Multiple rabbit deaths in the same household within a short period

Because most cases present as sudden death with little or no warning, the practical implication for owners is that surveillance and vaccination matter far more than watching for early signs, since by the time signs appear there is rarely time to intervene.

Recognising the Rare Survivable Case

Given the peracute course, diagnosis in a living rabbit is uncommon; post-mortem findings of hepatic necrosis and evidence of disseminated haemorrhage across multiple organs are suggestive, with confirmation requiring PCR testing of liver tissue at a specialist or reference laboratory.

In a household with a sudden unexplained death, especially where other unvaccinated rabbits are present, veterinary advice typically includes isolating remaining rabbits, arranging urgent vaccination of survivors if not already covered, and considering post-mortem testing to confirm the diagnosis and guide any public health reporting obligations.

Why There Is No Reliable In-Clinic Diagnostic Test

There is no specific treatment for RHDV infection itself; management of an affected rabbit is purely supportive and often unsuccessful given the speed and severity of the underlying liver failure and coagulopathy.

• Aggressive fluid therapy and supportive care in the rare rabbit that survives initial infection
• Vitamin K and other measures aimed at supporting clotting function
• Strict isolation of affected or exposed rabbits to prevent further spread
• Prompt vaccination of all in-contact rabbits not already protected

Vaccination Schedules and Practical Biosecurity

Vaccination schedules vary by region and product but generally require an initial course followed by regular boosters, commonly annual, with some combined RHDV1/RHDV2 vaccines and separate single-strain products both in use; owners should confirm with their vet which product and schedule applies locally given genuine differences in availability.

Because the virus is extremely stable in the environment and can be carried on insects, shoes, hay and other fomites, indoor rabbits are not fully protected by staying indoors alone; basic biosecurity such as washing hands after handling wild rabbits, controlling flies and quarantining new rabbits remains worthwhile alongside vaccination.

When to seek help urgently

• Any sudden death in an unvaccinated or partially vaccinated rabbit
• Blood-tinged nasal discharge in a lethargic rabbit
• Multiple rabbits in a household becoming unwell within days of each other
• A rabbit found collapsed or paddling with no clear preceding illness

Vaccine availability, strains covered and recommended schedules differ by country and even by region, so confirm the current protocol appropriate for your rabbit with your own vet.