Sudden or unexpected death investigation – can you help?

Unexpected death occurs more frequently in rabbits than in other pet animals. In order to find out more about the reasons for this, Frances and Nigel Harcourt-Brown are funding a “Sudden or unexpected death investigation”, offering histopathological investigations and arranging free ‘PCR testing for RHDV2’ on rabbits that die suddenly or unexpectedly.

Posted: 26 June 2018

Sudden or unexpected death investigation – can you help?


What is the purpose of the study?

There are many reasons why the study is taking place, but the main objectives are to;

  • encourage post-mortem examinations of rabbits that die suddenly or unexpectedly
  • help bereaved owners come to terms with the loss of their pet
  • help veterinary staff know why a rabbit has died under anaesthetic or while it was in their care
  • help take steps to protect other rabbits in the form of vaccination and biosecurity measures if the PCR test is positive for RHDV2
  • reassure owners that in contact rabbits should be safe if the PCR test is negative for RHDV2


“Sudden or unexpected death investigation” – the key facts

1. The investigation includes rabbits that die suddenly;

  • At home
  • During anaesthesia
  • During veterinary treatment
  • From euthanasia as a result of an unaccountable collapse

2. Eligible rabbits include those that are;

  • Kept as a pet in the UK
  • In a rescue centre

Note: Rabbits are NOT eligible if they are a breeding rabbit

3. Veterinary fees are NOT included

It’s important to note that funding does not include veterinary fees for post-mortem examination. It only includes histopathology. Vets and owners must be made aware of this.

4. RCVS Approval

The investigation has received ethical approval from the panel at the Royal College of Veterinary Surgeons.

5. The investigation does not include forensic pathology

Some conditions may not be detected from histopathology, such as;

  • Hypoxia
  • Head trauma
  • Brain disease
  • Electrocution
  • Hypothermia
  • Hyperthermia
  • Acute renal failure
  • Cardiac dysrhythmias
  • Acute toxicity – e.g. cyanide gas, Yew poisoning
  • Predator attack- especially if the rabbit has been grabbed by the throat causing vagal stimulation or hypoxia
  • Septic shock- from bite wounds or some peracute bacterial infections
  • Intestinal obstruction- although this should be evident from gross post-mortem finding
  • Enterotoxaemia- this may be evident from gross post mortem examination but post-mortem change can make diagnosis difficult.

Submit all tissues requested - it’s hoped that the findings of this investigation will complement the post-mortem reports that the Harcourt-Browns have collected for the last 20 years, which is why it is important to collect and submit all the tissues that are requested on the form plus any other tissue that appears to be abnormal.

Be aware that Rabbit Haemorrhagic Disease is not the only cause of sudden or unexpected death and other conditions can occur. Many of the common causes of sudden or unexpected death should be found from the gross post mortem investigation.

6. Support from Filavae

Filavie (the manufacturers of Filavac vaccine against RHD and RHDV2) are kindly providing free PCR testing for RHDV2 on liver samples from all the rabbits that are included in the study, not just the ones that died from RHD.

Be aware though that there will be a delay in getting results as they are sent away in batches.

7. What will PCR testing tell us?

PCR tests can confirm a diagnosis of RHDV2 in cases where the disease was suspected from histopathology. It may tell us more about the carrier status of rabbits and the reasons why vaccination doesn't always protect against RHD.

8. What can histology tell us?

Although histopathology can be diagnostic for RHD it cannot determine the variant.  If identification of the variant or confirmation of RHD is required quickly, then the reserve sample of frozen liver can be sent to BattLab or PALS, but this will be the owner's expense.

9. How the investigation works

Below are the details of how the investigation works. These details have all been obtained from the Frances Harcourt Brown’s (FHB) website.

  • Collecting tissues - these are collected during post-mortem. A recommended protocol can be found as a PDF from the FHB website.
  • Submission form - an Abbey Veterinary Services submission form is filled in online via the FHB website. Once it is completed, it can be saved and printed. A copy is then automatically sent to Frances Harcourt-Brown for her records. The FHB reference number on this form identifies the case and is useful to record for the results as they come through; this is not the same as the Abbey reference number.
  • Postage - a postage-paid address label for Abbey Veterinary services is printed out. After the tissues have fixed for 48 hours, the printed submission form and the fixed samples are submitted to Abbey.
  • Liver tissue - two pieces of unfixed liver are placed in a separate 20ml universal containers and frozen at the practice before packing carefully and posting to the Harcourt-Browns (not Abbey Veterinary Services). Frances Harcourt-Brown will send postage instructions to the e-mail address that is on the Abbey submission form once she has downloaded her copy from the website. A Filavie submission form needs to be downloaded, printed and filled in to accompany the frozen liver samples. One piece of liver will be sent to Filavie. The second will be stored at Harcourt-Brown's in case it is needed e.g. for testing for other variants of RHD.
  • Histology reports - a histology report will be sent to the practice from Abbey Veterinary Services and to Frances Harcourt-Brown as soon as it is available (usually less than 10 days).
  • PCR report - the PCR report will take longer than 10 days as the samples are shipped in batches of 50 to Filavie laboratories in France. It can be months before the results are available. As soon as they are reported from Filavie to Frances Harcourt-Brown, she will inform the practice, using the rabbit’s name and FHB reference number, to the e-mail address on the Abbey submission form.
  • Invoicing - invoices from Abbey Veterinary services are sent to Frances Harcourt-Brown
  • Discussion - the vet (not the owner) is welcome to discuss the results with Frances if they wish.

10. Complications - what could go wrong?

  • Autolysis or inadequate fixation of the tissues can lead to undiagnostic samples. Reports may not be issued for these samples.
  • If an incomplete set of tissues is submitted, these will not be processed under the scheme

11. Confidentiality and consent

Please be reassured that Frances Harcourt-Brown will hold no details of the owner. An information sheet about the investigation should be downloaded and given to the owner so they are fully conversant with the scheme.

Informed consent - requests for post-mortem examination, histopathological examination and PCR testing is obtained from the owner. They are also asked to give their consent to the use of the results in an investigation. The only information that will be recorded are;

  • rabbit's name
  • breed
  • age
  • sex
  • date of death
  • clinical history
  • post-mortem findings
  • histopathology report
  • PCR result
  • A FHB reference number

Find out more > 

For more information, check Frances Harcourt Brown’s excellent website.

Note: The information provided in this page have all been obtained from the FHB website and with the full consent of Frances Harcourt Brown.