In the past, RHD mutated to such an extent that the vaccines no longer worked against it and new vaccines were developed. This variant was called RHDv-2 and has been successfully vaccinated for several years.
In the north of France and other parts of Europe, a particularly contagious variant of RHDv-2 has appeared in recent months, against which the RHD2 vaccine (Eravac, Filavac, Nobivac Myxo-RHD PLUS) does not seem to be sufficiently effective. Unfortunately, epidemics do not respect national borders. The French Agence nationale du médicament vétérinaire (ANMV) has therefore approved the development of an adapted vaccine (ATU Filavac VHD Var K) that is effective against this variant. So far, this vaccine may only be vaccinated if it can be proven that the regular RHD2 vaccine is not effective.
Indications d’utilisation, en spécifiant les espèces cibles Immunisation active des lapins, dès l’âge de 4 semaines, afin de réduire la mortalité et les signes cliniques dus à la maladie hémorragique du lapin, provoquée par la souche du virus de type 2, et uniquement suite à un manque d’efficacité de la vaccination avec les vaccins contre la maladie hémorragique du lapin utilisés conformément aux RCP respectifs.Indication of use of ATU Filavac VHD Var K according to the package leaflet: The vaccine may only be used in the absence of efficacy of the regular RHD2 vaccines.
So far, the use is therefore limited to rabbit herds if there are deaths from RHD2 despite vaccination. If it becomes apparent that the variant of RHD2 also occurs among pet rabbits, the availability of the vaccine will be adjusted. Therefore, it is crucial to properly report any cases of ineffectiveness of regular RHD2 vaccines (rabbit dies despite correct vaccination and/or RHD2 was detected in pathology in vaccinated rabbits that died). Such cases of ineffectiveness should be reported to the manufacturer and the national animal disease authorities.
What should be done if the new RHD2 variant is suspected?
So far, there are mainly cases in France, but there may be a larger dark field, as cases of ineffectiveness of the RHD2 vaccines become known again and again. In such cases, it should be examined more closely whether it could be the new variant. For this purpose, the samples should be sent to institutes that can determine the variant more precisely.
If it is proven that animals have died from the new variant (through evidence at the FLI or ineffectiveness cases with correct RHD2 vaccination), it should be checked whether the vaccine can be imported.
How can I prevent this?
It is believed that animals that have been vaccinated widely and repeatedly have better protection against the new RHD2 variant. Rabbits that have been vaccinated once are particularly at risk. Protection can be improved by vaccinating a rabbit and then revaccinating it several times with different vaccines (e.g. Filavac every six months and Nobivac every year).
Fly protection (fly screens and spot-on such as Advantage II) and hygiene measures can also help!
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Thanks for the good article, I hope you continue to work as well.