The appearance of the new variant of viral hemorrhagic fever in rabbits in Europe has been very recent. First, in August 2010, atypical cases of Rabbit Hemorrhagic Disease (RHDV or Rabbit Hemorragic Disease Virus) were observed in northern France. It was characterized by affecting many rabbits that had already been vaccinated against RHDV and had a higher percentage of young rabbits. In 2012, the first cases of the new variant of viral hemorrhagic fever in rabbits began to appear in Spain and other European countries.

The virus causing this disease was closely related to the calicivirus that causes RHDV but was genetically and antigenically different. Therefore, it was concluded that it was a new variant.

What clinical signs does the new variant of viral hemorrhagic fever in rabbits present?
There are several forms of presentation of the disease:

Hyperacute Form: It results in the sudden death of rabbits without prior clinical signs of the disease.

Acute Form: Rabbits present fever, lethargy, apathy, and jaundice (yellowish mucous membranes) due to liver failure. They are usually animals in a state of shock and hypotension. Analytically, they show leukopenia, thrombocytopenia, and alterations in liver enzymes. Some may also exhibit signs of the classic disease, such as hematuria (bloody urine), bloody nasal or vaginal discharge. Generally, these rabbits die within the next 24-48 hours.

Subacute Form: The rabbit shows mild apathy and anorexia. After overcoming the clinical signs, it becomes immune but remains a carrier with the ability to transmit the disease for at least the following month.

How can the spread of the new variant of viral hemorrhagic fever in rabbits be prevented?
Vaccination is the only effective way to protect our rabbits against this new disease. The vaccines that have been used so far against the classic form of viral hemorrhagic fever do not protect against the new variant. Currently in Spain, NOVARVILAP by Laboratories Ovejero and ERAVAC by Hipra Laboratories are commercially available. They are administered every 6 or 12 months depending on the degree of exposure to the disease.

The virus is highly resistant in the environment and very virulent, so infection spreads easily. It can withstand freezing temperatures and temperatures of up to 50-60ºC. Therefore, to minimize contagion, the following guidelines are recommended:

Quarantine and isolate new rabbits that are to be introduced into a group.
Use mosquito nets in the summer to prevent access by mosquitoes and other vectors.
Avoid taking rabbits to the countryside or areas where wild rabbits or hares may be present.
Implement good disinfection protocols in affected areas, using virucidal products on the environment, cages, feeders, drinkers, and clothing. Do not reuse contaminated utensils; dispose of them if possible.
Do not collect wild plants to feed domestic rabbits.

How can the new variant of viral hemorrhagic fever in rabbits be diagnosed?
There are currently commercial laboratories that have developed a PCR for virus detection from blood, feces, urine, or conjunctival exudates. Detection can also be done post-mortem by performing a PCR on liver tissue or by recognizing the characteristic lesions observed in histopathological studies after necropsy.

How does it differ from classic viral hemorrhagic fever?

The incubation period is longer. Normally, it ranges from 4 to 9 days instead of the 1 to 4 days seen in the classic form.
It not only affects European rabbits (Oryctolagus cuniculus) but can also affect hares. It is not transmitted to any other lagomorph or rodent.
The virus can also be transmitted through feces because it has intestinal tropism. In addition to other forms of transmission, such as the rabbit’s bodily secretions (urine, nasal secretion, conjunctival secretion, or saliva), work utensils such as feeders, drinkers, food, or clothing, contaminated vegetables, as well as vectors (mosquitoes, fleas, ticks, etc.). It can also be transmitted through the feces of predators that may have consumed the bodies of deceased infected rabbits.
It affects rabbits under one month old, while RHDV1 affected rabbits older than two months at a minimum.
It has lower mortality (10% in adults and up to 50% in young rabbits) compared to the classic disease, which could reach 90%. This allows for a greater number of surviving carrier rabbits, which represent a new source of virus transmission.
Vaccines used against RHDV do not protect against RHDV2.

Frequently Asked Questions About Vaccination

How many diseases should I vaccinate my rabbit against? You should vaccinate against 3 viruses: myxomatosis, classic viral hemorrhagic disease (RHDV), and the new variant of viral hemorrhagic disease (RHDV2).
Do the vaccines that previously protected my rabbit also protect against the new variant of viral hemorrhagic fever in rabbits (RHDV2)? No, the vaccines from Nobivac (Lab. MSD), Cunipravac (Lab. Hipra), or Arvilap (Lab. Ovejero) do not protect against the new variant. This should be added to the established vaccination schedule.
What vaccination schedule do we recommend? Vaccinate every 12 months against RHDV (Viral Hemorrhagic Disease, classic variant). Vaccinate every 6 months against RHDV2 (Viral Hemorrhagic Disease, new variant). Vaccinate every 6 months against myxomatosis.

If you have any doubts, you can contact us or call us at 963227304.