VHD is caused by a virus. The virus is thought to be part of the Calci family of viruses, although the Journal of Applied Rabbit Research has found some evidence that the virus may be a parovirus. Yes, VHD is highly contagious. Other possible carriers include insects, rodents, birds, cats, and dogs. The virus can also be carried by human skin or clothing.
Warmer temperatures tend to reduce the viability of the virus.
Whether this is true, however, has been a matter of debate among scientists that have studied the disease. Scientists in Australia and New Zealand have found antibodies to the virus present in people who handled rabbits infected with VHD and in 11 species of animals in those countries. The presence of antibodies is generally a reaction to infection. However, no instances of illness or death due to VHD in humans or animals other than European breeds of rabbits have been reported. While vaccines for preventing the disease have been developed in Europe, the vaccines are not available in the United States.