Viruses of the genus Lyssavirus, the most prominent of which is rabies virus (RABV), are the causative agents of the deadly disease called rabies, which is transmittable exclusively to mammals. Rabies affects the central nervous system and has a variable incubation period. Reservoir hosts are bats and carnivores, among which the virus is transmitted enzootically, but there can also be epizootic transmission events, i.e. spillover infections, the transfer of the virus to a new species that becomes a new virus host. The transmission to a new host species is often the result of preadaptation of the virus and represents a great danger for humans and potentially endangered animals. Because of this feature of the virus, it is difficult to determine its origin, and only hypotheses can be put forward. In addition to biological barriers, virus transmission is also slowed down by geographical barriers, especially when it comes to terrestrial mammals as hosts. On the other hand, the spread of the virus among bats is most affected by seasonal changes, so that in the winter the virus spread stagnates due to bat hibernation. Efforts are being made to improve the diagnostics of lyssaviruses in order to determine their specific types, to obtain more reliable data on their distribution, and ultimately to develop the most effective strategies to control the disease.