Human Rabies Encephalitis Prevention and Treatment: Progress Since Pasteur's Discovery

Rabies remains one of the most ancient and deadly of human infectious diseases. This viral zoonosis is transmitted principally by the saliva of infected dogs, inducing a form of encephalomyelitis that is almost invariably fatal. Since the first implementation, by Louis Pasteur in 1885, of an efficient preventive post-exposure treatment, more effective protocols and safer products have been developed, providing almost 100% protection if administered early enough. However, this disease still represents a major, but neglected public health problem, with an estimated 55,000 human deaths due to rabies reported each year, mostly in Africa and Asia. Once the first clinical signs appear, there is no effective treatment. A ray of hope emerged in 2004, with the report of a patient recovering from rabies after aggressive, innovative treatment. However, this case was not clearly reproduced and the identification of targets for antiviral treatment in cases of rabies infection remains a major challenge. In this context, this review presents the state-of-the art in the prevention and curative treatment of human rabies. We begin by describing the viral etiological agent and the disease it causes, to provide an essential background to rabies. An overview of the post-exposure prophylaxis of rabies in humans is then given, from its initial implementation to possible future developments. Finally, an analysis of the various antiviral compounds tested in rabies in vitro, in animal models or in humans is presented, focusing in particular on potential new strategies.