Wild lagomorphs, including rabbits, hares, and pikas, in Western states are dying in large numbers from Rabbit Hepatitis virus II.  The causal agent is a calicivirus, which apparently originated in China in 1984 with variants of the infective agent since spreading worldwide.  Rabbit hepatitis virus has been used as a biological control agent to destroy wild rabbits in Australia.  The RHDV2 variant appeared in the U.S. in 2018 and is believed to have been introduced from Europe.There are two inactivated vaccines available in Europe, but efficacy against RHDV2 has yet to be determined.

An unfortunate choice of nomenclature will undoubtedly result in concern among the public.  A veterinarian based in Texas inappropriately referred to the infection as “Bunny Ebola”.  Using the term Ebola, which is a serious hemorrhagic and frequently fatal infection of humans, endemic to Central Africa creates a misleading association. The misappelation will require strong statements from USDA and health authorities that RHDV2 is a disease of lagomorphs and does not affect humans.

USDA regard the infection as a “foreign animal disease”, but based on mortality in wild rabbits and hares it should now be regarded as endemic as it is in Canada.