RHD in pet rabbits. Is it possible for it to spread in indoor rabbits?

It is clear that, for most infectious diseases, animals that have direct contact with the outdoors are often the ones that are most exposed to pathogens. Therefore, they are the ones that have a higher risk of becoming infected and suffering from the disease. Pet rabbits are no exception. However, the rabbit haemorrhagic disease virus is highly resistant in the environment, especially when it is protected by organic material.

VIRUS SURVIVAL

• More than 3 months on fabrics in a dry state at room temperature.
• Up to 20 days at 22ºC in decomposing rabbit carcasses
• In refrigerated or frozen rabbit meat.

Furthermore, it survives a wide range of pH values (>3 and <12).

All this makes the risk of an indoor rabbit becoming infected higher than with other pathogens.

On the other hand, in many regions of the world, leporids, which include the genera Sylvilagus, Lepus and Oryctolagus, among others, are present in wildlife and can act as a reservoir for the virus. Considering that RHDV can survive 20 days at 22ºC in decomposing rabbit carcasses, transmission by indirect contact, either by stepping on the faeces of infected wild rabbits, collecting food in unpopulated areas or even dogs that can feed on these animals, can lead to contagion of an indoor rabbit.

At the WSAVA congress that took place in Peru in 2022, the following study was presented: “Rabbit Hemorrhagic Disease (RHD) in six indoor pet rabbits diagnosed in the same week in Portugal: a case series”. This study described the detection of 6 cases of RHD in indoor rabbits from 2 cities in Portugal in the same week (Image 1).

It is extremely difficult to be sure how an indoor pet rabbit has been infected with the rabbit haemorrhagic disease virus. As it is a highly resistant virus in the environment, it is usually a matter of suspicion, without confirmation of the transmission route. For these reasons it is important that we ensure correct immunization against RHD in indoor and outdoor rabbits.