The post-exposure management of cats depend on the national public health regulations, but is forbidden in many countries. Usually, it is not authorised in case of clinical suspicion. No supportive or specific treatment has proved to be effective in rabid cats, so treatment is not recommended [Greene & Rupprecht, 2006].
Rabies in cats is usually controlled by traditional inactivated vaccines [OIE 2007] and at present, several inactivated rabies vaccines are available commercially. These products have been shown to induce protective immune responses following a single vaccination [Fu 1997, Perez and Paolazzi 1997]. In cats and dogs, the peak of rabies neutralizing antibodies is generally reached between 4 to 6 weeks after the first immunization [Cliquet 2006]. Currently available inactivated vaccines are very efficient. Cats and dogs with a neutralization titre above 0.5 IU/ml, regardless of the period of time elapsed since vaccination have a very high probability of survival after a rabies infection [Cliquet, 2006]. Cats respond better to rabies vaccination than dogs and as much as 97.4% of them develop a titre of 0.5 IU/ml or higher after the first vaccination, many even above 5IU/ml [Cliquet, 2006]. A very small proportion of cats identified with rabies have had at least one rabies vaccination during their lifetime [Greene et al, 2006]. Since the new EU regulations in pet movement were put in place in 1993, no single case of vaccine failure has been documented [Cliquet 2006]. Rabies vaccines are generally considered to be safe, even in neonatal kittens.
Inactivated vaccines may carry a risk due to the remote possibility of incomplete inactivation of the virus and the inadvertent spread of residual pathogenic particles of rabies virus [Schneider, 1995]. Furthermore, inactivated rabies vaccines may be associated with the development of injection site sarcomas in cats [Dubielzig et al, 1993].
Such problems led to continued efforts to develop safer rabies vaccines. New vaccines include recombinant subunit proteins [Wunner et al, 1983], recombinant viral vectors [Paoletti 1996, Xiang et al, 1996] and deoxyribonucleic acid (DNA) based vaccines [Osorio et al, 1999, Cupillard et al, 2005]. Recombinant live vector vaccines have some advantages over traditional vaccines: they are innocuous, they induce suitable humoral immune responses and they do not require rabies virus to be handled [Paoletti 1996]. They also induce less inflammation at the site of injection [Day et al, 2007].
Fortunately, current vaccines are also cross-protective against a number of other Lyssavirus genotypes. All cat and dog sera with a titre above 5 IU/ml neutralize EBL-1 and EBL-2 regardless of vaccine/virus strain and among sera with a titre between 0, 5 and 5 IU/ml 87% neutralize EBL-1 and 53% EBL-2 [Fooks, personal communication]. However, against some novel lyssaviruses isolated from bats in Eurasia the protection may be reduced or negligible depending on the genetic distance between the new isolate and traditional rabies viruses [Hanlon et al, 2005].
Because of the public health risk associated with susceptible domestic cats becoming infected following exposure to rabid wild or domestic animals, rabies virus vaccines should be considered as core vaccines in countries where rabies is endemic and should be administered in accordance with local or state regulations.
In countries where rabies is not present, rabies vaccination may be considered optional, to be recommended by the veterinarian if the cat should move to an endemic rabies area.
In contrast to all other inactivated vaccines, a single rabies vaccination induces a longlasting immunity due to the immunogenic properties of the vaccinal antigen.
Kittens should be vaccinated at 12 to 16 weeks of age to avoid interference from maternal antibodies, with revaccination one year later (depending on data sheet recommendations for each brand of vaccine). With this schedule, a single vaccination is sufficient. However, national or regional legislation regarding vaccination type and interval should be adhered to.
Although some commercial vaccines provide protection against virulent rabies challenge for 3 years or longer [Lakshmanan et al, 2006], national or local legislation may require annual boosters.