VIRAL INFECTION OF RABBITS

The three most important viruses of rabbits include: Myxoma virus (MV), the poxvirus that causes Myxomatosis, the calicivirus (genus Lagovirus) of Rabbit Haemorrhagic Disease (RHDV), and Lapine Rotavirus (LRV), which is an enteric agent. There are some other viral agents in rabbits (parvovirus, coronavirus, adenovirus, calicivirus (genus Vesivirus), enterovirus-like, reovirus, herpesvirus and coronavirus) but both their occurrence and their pathological value are negligible. Myxomatosis was firstly introduced in Europe more than 50 years ago and still represents a current and real problem. Recent studies have been focused to determine the role and function of the over 100 genes of MV encoding structural and essential proteins; in particular the immunomodulatory MV (im-MV) proteins (virokines and viroreceptors, immune modulators and anti-apoptotic factor), involved in contrasting the host immune system response towards the MV infection. One of the main tools to control myxomatosis in endemic areas is use of the live attenuated vaccines that are able to induce traceable humoral immunity for a variable time even if the protection of rabbits from the infection is not fully guarantee. Therefore, thanks also to the knowledge on the im-MV proteins, a new family of biotechnology deleted vaccines will soon be produced and made available in a few years. These should be more safe and able to induce a wider immunity and permit to apply the DIVA strategy i.e. to use serology to ascertain if the anti-MV antibodies detected in a rabbits originate by an infection or a vaccination. RHDV is a non-cultivable calicivirus that infects rabbits and causes an acute fatal hepatitis, firstly described in China in 1984. The first consistent antigenic variant called RHDVa, was identified in Italy and Germany in 1997. Nowadays it is present in most parts of Italy and its field prevalence ha