This is in response to your fax of July 25. Firstly I would like to apologize for the slow response. At this time, I am on sabbattical in the Netherlands studying Swine Fever. Your fax was forwarded to me from Plum Island. Thus, my response has been delayed. It is difficult to respond to your questions in a letter because the answers are not straight forward. There has been a great deal of work done to identify the causative agent of rabbit hemorrhagic disease. Work has been done first in China, then in Europe, Korea, and Mexico. During the Mexican outbreak, samples were sent to Plum Island for diagnosis and considerable effort was given to this virus.

When a new virus occurs in the world, any claims as to the cause must meet many standards. The classical standards which are still valid today were described by Koch in the 1800’s and are referred to as koch’s postulate. That is, a disease agent must first be isolated in culture and then reintroduced into the host and the same disease should be reproduced. With RHD, this simply has not been accomplished except perhaps by the workers in the Peoples Republic of China. They claim to have isolated and passed the virus more than 10 times in cell culture and reproduce the same disease in rabbits from the cell cultured virus. No other laboratory has replicated their results. They claimed to have found a parvovirus and present considerable supportive evidence for this claim. I would refer you to several articles in the Technical review book published by the OIE on Viral Hemorrhagic Disease of Rabbits. OIE is the Office of International Epizootiology in Paris. It is an independent organization of member countries dedicated to the control of animal diseases. This book reviewed nearly all the work done on this disease at the time of publication. Each article was written by the primary investigator. All reviews were presented by the original investigators. Nearly all of our findings were published in this book. It is still available from OIE, and I strongly recommend anyone with a strong interest in this disease to study this reference book.

Now, perhaps this is the long answer. The short answer is that I agree with the Chinese workers that there is likely a parvovirus involved in the disease. This opinion is based on comparative pathology, electron microscopy, comparative immunology, immunohistochemistry, and in-situ hybridization. Many other workers in Europe, using less traditional methods of molecular biology claim that the agent is a calicivirus. Their results are interesting and cannot be ignored. The final answer awaits the fulfillment of Koch’s postulate in more than one laboratory. Until the agent can be isolated in vitro and the disease then reproduced, most scientists should be skeptical.

I am including in this fax the address of the OIE so that you may purchase a copy of the Technical Review. If you choose not to get a copy, you can request from my Plum Island office of the Foreign Animal Disease Diagnostic Laboratory a copy of my article on this disease outbreak in Mexico from the Technical Review of Viral Hemorrhagic Disease of Rabbits by the OIE.

You may fax the secretary at 516-323-2798. Please request a photocopy of the book article, since there were no reprints published for distribution. I am sorry I cannot send you a copy from here, but I do not have a copy of the book in the Netherlands.