Diagnosis of RHD

The diagnosis of RHD is usually made after death. A presumptive diagnosis of RHD can be made when more than one rabbit in the household has died suddenly, especially if they were unvaccinated adults. The ‘classic’ appearance of a rabbit that has died from RHD is in opisthotonos with a haemorrhagic nasal discharge, but this is not seen in every case (Rosell et al. 2019). Post-mortem examination is essential to make a definitive diagnosis of RHD and to rule out other causes of death. Histopathology can confirm or refute a diagnosis RHD and gives valuable information about other causes of sudden death. PCR testing confirms the presence of RHD viral antigen and determines the serotype.

Post-mortem examination at a pathology laboratory or in-house by a veterinary practitioner?

Ideally, a comprehensive post-mortem examination, including assessment of the central nervous system, performed by a veterinary pathologist should be performed on every rabbit that dies suddenly. Facilities for further testing, such as microbiology are close, and the procedure is carried out by a trained pathologist. However, in-house post-mortem by the veterinarian in charge of a case has many benefits:

• The post-mortem examination can be carried out soon after death, which is particularly important in rabbits. Ideally the examination should be carried out within 6 hours of death because autolysis occurs rapidly. Autolysis interferes with the macroscopic and microscopic appearance of the organs even if the carcase was chilled in a refrigerator.
• Causes of sudden death with obvious gross post-mortem findings can be seen. Examples include neoplasia, gastric or intestinal rupture, peritonitis, gastric dilation and intestinal obstruction, liver lobe torsion or ureteral obstruction and hydronephropathy.
• Fresh tissue can be collected and fixed for histopathological examination or frozen for PCR testing.
• There may be cost benefits for the owner.
• The body can be returned to the owner for burial or cremation.