Update On The Rabbit Calicivirus Outbreak

This entry is part 5 of 5 in the edition Bunny Business

Updated June 19, 2024

Update 2018:

To those who love rabbits it’s been a tough few years.

On the 24th of February, 2016 we were notified that the new strain of Rabbit Hemorrhagic Disease Virus called RHDV2 had reached South Australia and was causing deaths around Adelaide.

We posted an alert on our Facebook page, and only then did the true horror of what was happening become clear.

Pet rabbits were dying in yards far from other rabbits, and losses by commercial breeders were high. Most owners had no idea their rabbit was one of many casualties and that there was a silent mass epidemic underway. The Facebook comments make for tragic reading if you delve into our page for February 25, 2016.

Could these just have been random deaths? Here’s why that’s unlikely:

  • So many deaths all at once are not a normal pattern.
  • Local researchers had proven that RHDV2 was now causing deaths (that’s their map above) around the edges of Adelaide.
  • Thanks to one of our clients we now had the proof that the virus is killing rabbits in the very heart of the

Roger died suddenly in the Adelaide CBD at the same time and his owners kindly donated their beloved rabbit for testing.

roger calici rabbit
Roger a few days earlier

The tests confirmed that he died of RHDV2 infection. That’s in a courtyard in the middle of a city. If he could get it, every rabbit is at risk.

In the same batch of testing were three other rabbits from Adelaide and the hills also positive for RHDV2.

Bearing in mind how few rabbit deaths are being thoroughly investigated, we think the majority of these unexplained deaths were due to the new calicivirus. Most experts agree.

How To Prevent Calicivirus Infection

There are no guarantees, but here is what we recommend to reduce the risk:

No access to gardens or garden clippings

The virus is probably being spread by flies leaving droppings and spots on foodstuff and housing. Keep your bunny inside and only feed commercially grown hay, pellets and veggies. Commercial foods can still be contaminated but the risk will be lower. For example, current hay for sale may have been made before this outbreak began.

Insect control

Don’t allow flies to come into contact with your rabbit. Being inside should be protective, but if they have an outside hutch, invest in some flymesh and attach it.

Hanging insecticidal pest strips nearby is another good idea but read directions carefully as these can be toxic if too close.

Choose a product from our list of registered parasite treatments for your rabbit.


Although less effective, we think the vaccine is still very helpful.

It has been recommended to vaccinate kits at 4 weeks, then at 8 weeks, and again at 12 weeks or later, followed by six-monthly vaccination. However, protection has been disappointing and deaths have occurred in vaccinated rabbits. Therefore, we have reverted to the vaccine manufacturer’s guidelines of annual vaccination. 

Vaccination should still give protection against classic RHDV and RHDVa strains like K5.

Where Did RHDV2 Come From?

The virus appeared overseas around five years ago, but was first reported in Australia in 2015. It was not deliberately released by Australian authorities. The fact that it probably came here by itself says a lot about how easily RHDV2 can spread.

What Are The Symptoms Of Rabbit Calicivirus?

The virus acts extremely quickly, and so in most cases no signs of illness are seen before death.

When seen, signs include lethargy, not eating or a soft mucous dropping. Sometimes at the time of death blood is seen around the nostrils (hence the disease name) but this is not a reliable indicator.

The presence of more than one sudden death is very suspicious but only laboratory testing can confirm the diagnosis.

What Else Causes Sudden Death In Rabbits?

The most common non-viral cause is Gastrointestinal Stasis, a nasty bacterial enterocolitis usually seen in rabbits on low fibre diets.

Fox attack in city rabbits is a lot more common than people realise.

Myxomatosis causes a prolonged disease with conjunctivitis and swelling of the eyelids, and survivors having swellings on the body called myxomas. Read all about myxomatosis here.

If your rabbit seems quiet, unwell or off food, get them checked by a vet ASAP. All is not lost.

Does Rabbit Calicivirus Affect Other Animals?

Dogs, Cats, Guinea Pigs, Horses, Chickens and other animals are all safe. The original Czech strain of RHDV and mutated varieties only affected rabbits. It is suspected that RHDV2 can also affect the European Hare.

Other species have their own calicivirus (for example, one of the cat flu viruses!) but like most viruses they don’t easily cross species barriers.

Why Is This Calicivirus Outbreak So Bad?

Speed Of Spread.

This virus behaves very differently in Australia to how it behaved in other countries. Instead of normal slow geographical spread it has leapt and jumped hundreds of kilometres a day.

Researchers here in South Australia have discovered that it is being spread by flies.

Less Vaccination

In 1996, botched though it was, the original RHDV was scheduled for a planned release before it escaped. That gave manufacturers the time to develop a vaccine. The subsequent media interest made rabbit owners rush to get their bunnies protected, and it worked. I don’t recall a single fatality in a pet rabbit during the initial outbreak.

This is the same vaccine we’ve used since and it’s done a good job. However, we think only a low percentage of rabbits are up to date with their vaccinations today. That allows the virus to jump from rabbit to rabbit even in urban areas.

Lack Of Awareness

The lack of publicity about this outbreak has also meant that we have been caught by surprise. If there had been more of a hue and cry we could have got the rabbits protected before the virus hit.

Possibly the successful prevention of serious problems in 1996 tricked us into underestimating the virus this time.

Reduced Vaccine Efficacy

This virus has only 85% similarity to the 1996 Czech strain. Researchers agree that the vaccine should still offer some protection, but it will neither be as effective or as long-lasting as before. Vaccinated rabbits are also dying.

Are Other States Affected?

Yes, it is certainly being seen in Victoria and New South Wales, although it does not appear to have hit Sydney and Melbourne yet like it has in Adelaide.  Here is the most recent RHDV2 map we know of for New South Wales.

We are lucky to have a specialised team of RHD researchers here which has sped up identification of the problem.

To those who see rabbits only as an agricultural and environmental problem we ask for your compassion for the large numbers of pet rabbit owners. These rabbits and their owners aren’t part of the problem.

So, are we beating this up? Nothing would make me happier than to be proved wrong but all my instincts tell me we’re in the middle of something big, unprecedented and tragic.

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

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39 Replies to “Update On The Rabbit Calicivirus Outbreak”

  1. Hello I have a female pet rabbit who had 4 kittens she died of calisi we think and the kittens seem alright only about 6 days old I am going to try to bottle feed them with they be effected by the virus because of the mother ?

    1. Hi Macy. I can’t be sure but what I do know is that when they released calici in Australia, it didn’t achieve eradication of rabbits due to survival of the very young kittens. Therefore there’s a good chance they might be okay.

  2. Thankyou for your expert advice, I cam across it while dong Calici research. I have lost many show rabbits over the last 7 years to calici (all our rabbits were vaccinated) most recently from 6 days ago. strain unconfirmed as yet as I still have them passing away but we vaccinate with Cyclap. I have watched over 80 of my presious rare fur babies vanish painfully from existance in the last 6 days. We need a viable v2 vaccine to save Australian rabbits and heart broken rabbit lovers.

  3. A month ago, we lost our whole family of rabbits – a buck and doe, 1yr 6months old, and their 7 eight week old kits. They were living in an outside insulated enclosure, with aviary mesh panels each side for ventilation. First the doe died suddenly, when she was perfectly fine just hours before. I moved the kits and the buck inside immediately, still separated, then 2 days later 3 kits died within hours. Vet said it was very likely calicivirus, and as they weren’t all vaccinated we made the heartbreaking decision to euthanize the remaining bunnies 🙁
    Can we use steam to deactivate the virus from our home, and safely adopt vaccinated kits?

    1. Hi Jo. I’m sorry to hear this – now that the virus is endemic it will cause periodic outbreaks like this and I suspect that your vets are right. I’m afraid steam will not sterilise adequately in the presence of household items and furnishings. It is in fact very difficult to remove it from a household environment; I would carefully clean and then wipe down all smooth surfaces with 10% bleach and wait six months, relying on regular household cleaning and time to do the job. If you are in Australia, it’s also worth knowing that we don’t have an effective vaccine. That’s thanks to the agricultural lobby.

  4. Hi we have just brought 2 Flemish rabbits, that we have outside and inside, we are already extremely attached to them, is there any cases in Wimmera Victoria? We have them going in for immunisations next week, they’re only babies and we haven’t started toilet training, I’m extremely stressed about letting them outside now even though they enjoy it immensely ☹️ any advice or ideas would be greatly appreciated, we are thinking of building them an outdoor room in our veranda?? Thanks so much in advance x

    1. Hi Louise. We aren’t seeing many cases of calicivirus in mainland Australia at present (2020) but it’s now endemic in the wild population so the risk will be consistent even if low. Therefore, although having an outdoor rabbit should be okay, things could change quickly based on the local rabbit population and we generally advise that rabbits live inside. This is especially because the current vaccination, although certainly recommended, offers insufficient protection against RHDV–2.

  5. Hi i lost 3 of my mini lops to the R2 virus 3 weeks ago. Sweet Pea, Zack & Zorro showed no signs until an hour before death. All died at 1 year 6 months. i have 2 other bunnies Ace & Riley are 3 months old in a different yard and are doing well. I don’t know what to do with my old hutch, its an expensive metal one but i don’t feel comfortable using it for other bunnies.

    1. Hi Gabby. I’m very sorry to hear that. The hutch should be reusable if you pressure clean it and then scrub it down with bleach. Though of course, it’s impossible to guarantee so you may feel better just throwing it away.

  6. We had 2x 7 month old minni lop adults who bred 5 kits born april 1st dad was very loving towards kits (but still seperated from mum) when kits where 3 weeks old mum seized and died after having penned outside time when local hazard reduction burns were taking place In our rural area on Friday night. Next 24 hours we lost 2 kits even though they were eating healthy being hand fed by Saturday night we swapped cages with Dad on Sunday and in 3 hours we lost dad took to vet on Monday with kits autopsy completed and calaci confirmed by 10am Tuesday we lost 2 more kits after keeping them in storage box instead of regular cage we currently have 1x kit left Snowball who has made it to 8 weeks and just received first vaccination due again in 4 weeks . We had no idea that calaci was even in a existance or how fast the spread takes effect Snowball is still an inside rabbit vet has instructed we could cage her safely back into plastic/wire cage I went overboard googling calici and soaked cage for 2 weeks in diluted bleach then disinfectant and then rinsed in water plus gurnied we put her back into cage and in 6 hours she became very irregular in behaviour and was lying on her side panting she was removed asap and is still in storage container as home the vet also advised she would be safe/immune after 3 weeks to return to be introduced to outside time and grass the area we intend also has the grave of her 4 siblings plus mum and dad I maybe a stress head but after such a significant loss and how special she is to our family and after reading site information and comments I don’t feel I have been instructed as well as I could have been by family vet. We intend for her to be an inside pet as she is also a pure albino so outside time would be limited but would outside ever be an option.
    She will also receive her very own mansion cage brought brand new.

    1. Hi Melinda. I’m sorry to say that your experiences with calici are very common. I suspect the hazard reduction burns brought wild rabbits close by looking for fresh feed or to escape and contaminated the ground. It’s now going to be a long time before the outside is safe for a rabbit again, probably around 12 months, and I wouldn’t rely entirely on the vaccine. Good luck.

  7. Hi all,
    I have just lost my two rabbits this past week… Our council has just released the latest calici strain in my suburb three months ago without prior warning, I am devastated.

  8. I’ve had a rabbit die of calicivirus, I’m wondering if the large (expensive) rabbit run/hutch she was in can be used again, and if so what I need to do to prepare it so it is safe again. It is wood/wire materials and a plastic base on two removable ‘littler’ trays. I don’t have the heart to reuse it myself after the loss, but obviously I couldn’t pass it on to anyone unless it was safe – yet it would be an incredible waste to smash it up and bin it if there’s a chance a bit of effort would make it useable again, can anyone advise?

    1. Hi Alex. Sadly, calicivirus is extremely hard to disinfect. I would scrub it to remove ALL organic matter including in crevices and then spray it thoroughly with 10% bleach solution (buy good quality bleach too) three days in a row. Even then there’s no guarantee.
      My other thought is the diagnosis. It’s impossible to prove without virus isolation and a much less common cause of death than gastrointestinal stasis. I suggest you click on the link and have a read.

      1. Hi, we live in Green Point, Central Coast, NSW and last night we found our pet rabbit deceased. Blood from his mouth and nose and genitals. No earlier symptoms of anything wrong with him. It appears the Calicivirus has reached the Central Coast. Our poor bunny was 4 years old, was born on Easter Sunday and we actually watched his mother give birth to him. He was the only survivor or the 4 babies. So yes, he was very special. My 17yr old daughter is devastated.

  9. We lost our bunny family 8 months ago from what I believe was RHDV2. I hope it is now safe to consider having another rabbit in our home but am worried about ensuring our home environment is safe now. Wondering if we should have disposed of plastic carry cages. We washed at the time but, it has been suggested we dispose of them. Is that necessary or is bleach, f10 and time adequate? Should outside play time be banned for domestic rabbits all together and is commercial hay safe to use at the moment?

    1. Hi Debbie. The plastic cages should be okay if they can be completely cleaned and disinfected with bleach, as long as there are no nooks and crannies that residual virus could hide in. As for whether it safe to go outside, it depends on whether the area has been contaminated in the past. If so, I would wait 12 months. The outbreak has effectively died down but we are going to see sporadic deaths like yours into the future. Hay seems to be safe in that we do not see increased deaths in the rabbits that ate it, in fact they are generally healthier. Good luck

  10. Is it safe to bring a 12 week old rabbit into an inviroment we’re three rabbits have died of the RHDV2

    1. Hi Laura. Sadly it is very unsafe to do so. You will see other comments below about disinfection. All the best.

  11. Hi there,

    I was the owner of a house rabbit who lived in an apartment. We met a bunny to adopt and he died and a few days later my beloved rabbit died too. The vets suspect calici. My bun was allowed all over the apartment never ever caged – how long should I wait before getting another rabbit?

    1. Hi Natascha- sorry to hear and yes, it does sound like calici. I’m afraid the virus is very stable in the environment.
      The following research gives some hope that a process such as steam cleaning of carpets and bleach mopping of smooth floor surfaces might be effective.
      A study was conducted to investigate the persistence of rabbit haemorrhagic disease virus (RHDV) in the environment. Virus was impregnated onto two carrier materials (cotton tape and bovine liver) and exposed to environmental conditions on pasture during autumn in New Zealand. Samples were collected after 1, 10, 44 and 91 days and the viability of the virus was determined by oral inoculation of susceptible 11- to 14-week-old New Zealand White rabbits.
      Evidence of RHDV infection was based on clinical and pathological signs and/or seroconversion to RHDV. Virus impregnated on cotton tape was viable at 10 days of exposure but not at 44 days, while in bovine liver it was still viable at 91 days. The results of this study suggest that RHDV in animal tissues such as rabbit carcasses can survive for at least 3 months in the field, while virus exposed directly to environmental conditions, such as dried excreted virus, is viable for a period of less than 1 month. This study must be interpreted with caution for rabbit owners as NZ pasture conditions were likely to have been wet, unlike indoor environments.

      Henning, J., et al. (2005). Survival of rabbit haemorrhagic disease virus (RHDV) in the environment. Epidemiology and Infection 133: 719–730.

      1. He died at the end of March – I was planning to wait until the end of October. I have been trying to F10 as much as possible. Do you think this sounds acceptable? Thank you so much for your quick reply and the information.

      2. Yes, that sounds sensible. However, bleach at appropriate dilutions is probably superior to other disinfectants where fabrics are not involved.

  12. Hi
    Just wondering if the vaccination for calci is available in any other country ? And why is it not avaialavke in Australia yet?

    1. Hi Meeraj. That’s a very good question! It’s fundamentally a political problem, where the authorities are heavily influenced by the agricultural sector. They are concerned by potentially protecting wild rabbits if the RHDV2 vaccine strain escapes. As much as I think this is ridiculous, I’ve spoken directly with Canberra and I don’t think there’s much hope of changing their minds until there is an inactivated calici vaccine we can import.

  13. My bunny has been very unsettled because he has so much energy, and running around inside feels pointless so I’ve been wanting to let him outside in a play pen to run around and enjoy the serenity, but I’m worried that he’ll catch the virus. He’s been vaccinated but that doesn’t feel like it’s worth the money to get done again, and again and again. Feeling a bit hopeless for the little fella at this point.

  14. Hi! Just a bit worried about purchasing vegetables from the woolies or coles etc because I’ve heard that the virus may contaminate the produce? What do we do? 🙁

    1. Hi Jo – we are not aware of any known deaths occurring using supermarket vegetables. As a precaution, rinsing vegetables should help. I don’t not think that market gardeners would allow rabbits in their fields though!

      1. Thanks so much for that! 🙂 we were so worried we won’t be able to feed our bun veggies anymore… thanks!! ????????????

  15. We live in Melbourne metro. Just lost 5 beloved Flemish giant free range bunnies in one week (Nov). All bunnies were thought to be protected and all measures to save them i.e. critical care failed. Rabbit vet refused to see them. Definitely calicivirus. Is the soil now contaminated and if so, for how long?

    1. Hi Brooke. It’s a good question and sorry about your losses. Caliciviruses are very resistant to environmental breakdown so a reasonable estimate would be one year before the soil is safe.

  16. In country NSW 3,000 plus rabbits died from RHD2 vaccinated if you are growing meat rabbits you cannot vaccinate young kits ! and at $9 a dose if you do it bulk and most vets here charge over $90 per visit !! primary producers can only do their breeding stock what hurts is they have a vaccine France UK Hungary as they produce a lot of meat a few buuny pet owners will not get this here !! the government regards all domestic rabbits as a pest … akubra now source overseas .. b4 the pet folk go glad meat rabbits are gone ..or breeders your pet bunnies all came from meat rabbits …and we all need to fight this Together

    1. We’ve been in touch with the APVMA and federal department of agriculture and the news hasn’t been encouraging. Unless an international vaccine manufacturer sponsors the application to import, it’s doomed to failure.

  17. I am extremely concerned for my rabbit Stewey. I have had him for close on 7 years now, and we love him. Stewey has the full run of our backyard and is put back each night into a closed off section to keep him safe from ‘night predators’ – cats, foxes. I have had him vaccinated against a particular strain of calicivirus every year, but now fear of this new virus in Adelaide. I hope that people power and Vets can demand (quickly) for the vaccine to be made available in Australia – as I will be the first one in the line up at my local Vet !

  18. Hi just letting you know our rabbit died suddenly tonight. He was only a year old. I think he may have gotten this virus. We had noticed he was a little less responsive to us but he was still eating as normal up until yesterday

    1. Heather, I am so sorry to read of your loss. Please consider having a necropsy done to determine RHD and what strain. It’s important towards getting a vaccine specific to the deadly RHDV2. I apologize for bringing up this matter at such a distressing time.

      1. Thanks Jane. What you say is correct, but it’s worth checking with the local vets first that they have access to testing and how much it will cost. It’s actually very hard to access. In our case we were very lucky to have contact with a team of researchers.

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