RVHD1 & RVHD2 – An Overview
Updated Dec 2016.
RVHD1 and RVHD2
This article will provide a concise overview of Rabbit Hemorrhagic Viral Disease, its characteristics, locations, testing methods and some of the preventative steps that can be taken.
Rabbit Viral Haemorrhagic Disease 1 is a type of Calicivirus, has been in Europe for many decades or even centuries and affects both wild and domestic rabbits. There are a few different pathogenic strains of the virus but until recently, RVHD1 was thought to be the only type in the UK.
RVHD2 differs in a few key ways as it is unaffected by age and has a longer illness phase with different clinical symptoms. It is also thought to have a lower mortality rate. Little research has been done on RVHD2 and it is highly likely that cases are under reported.
Both viruses are potentially very easily spread and can live in the environment for a long time (RVHD2 up to 200 days in laboratory conditions) Insects, wildlife and scavengers can spread it as well as direct contact with an infected rabbit. Fomites such as bedding, wild plants, shoes and clothing can also carry the virus to new areas. It is currently unknown if biting insects can spread RVHD2.
Due to it being so easily transported, the spread of RVHD can be very quick and strict biosecurity is recommended as well as vaccination.
The current UK vaccine, Nobivac Myxo-RHD offers protection against RVHD1 but is unlikely to offer any for RVHD2 as this virus is antigenically and genetically different from RVHD1. It is recommended that a second vaccination be given to cover RVHD2 and there are a few options:
- Eravac has been licensed in the UK for use in ‘fattening’ rabbits. This is an oil based drug with no research showing the possible long term effects and there is currently no recommended vaccination schedule.
- Cunivak RHD is currently out of stock and Cunipravac can be ordered via a special import certificate however it is only available in large multi dose bottles.
- Filavac RHD K C+V is available to order from most UK wholesalers and is administered annually or 6 monthly (if considered to be a high risk patient or area). It is vital that the rabbits are still vaccinated with the Nobivac Myxo-RHD as the Filavac vaccine does not give any protection against myxomatosis, however standard immunology advice is to leave at least a 2 week gap between the different vaccinations.
It is important to research all options and discuss with your vet / client. The safety and efficacy of using any other vaccine alongside the Nobivac Myxo RHD has not been studied.
It is not recommended to carry out en-mass vaccination clinics as this could potentially increase the risk of disease spread due to the way RVHD is transmitted.
Testing and Reporting
Its important to consider RVHD2 as a differential diagnosis when dealing with a sick rabbit that doesnt seem to respond to treatment and no obvious reason for the illness is found. PCR testing is now available for live rabbits via the Batt Laboratories in Coventry. For sudden deaths, post mortem liver samples can also be sent here or to the Moredun Research Institute.
Wherever possible, please send samples to either laboratory via the methods outlined on their websites. Please also consider reporting all suspicious deaths to the Rabbit Welfare Association and Fund as their Veterinary Advisor is monitoring the spread of this disease.
Good husbandry is paramount and sick rabbits should be barrier nursed. Enhanced cleaning, disinfection and quarantine protocols can be implemented in practice and with owners. Anigene HLD4V is a veterinary grade product that is believed to be effective against RVHD when used at a concentration of 1:50 for soiled conditions.
It is vital to be aware of the risks associated with attending events such as rabbit shows, petting zoos and even rescues. Environmental insect controls should also be in place as it is still unknown if RVHD2 can be spread via insects. Care should also be taken when considering feeding handpicked wild plants.
Keeping Up To Date
You can also visit the Rabbit Welfare Association’s website as they will always have the most up to date and factually correct info.
Lastly, Rabbit Specialist Vet Francis Harcourt Brown (retired) has information about the disease on her website.
Be wary of other reports and anecdotal stories doing the rounds as they may not be factually accurate. Also, please contact your own vet asap so they are fully aware of the new RVHD2 strain and that they are stocking and advertising the new vaccine to help fight this. We need owners to insist all their vets order in the vaccine to get as many rabbits as possible protected against this fatal disease.
Please know how to keep your rabbits safe and spread the word!