Rabies virus particle, animation. This bullet-shaped particle consists of an RNA (ribonucleic acid) genome enclosed in protein capsid, which is itself surrounded by a lipoprotein envelope containing glycoprotein spikes (red). Rabies virus primarily infects animals but can be transmitted to humans through a break in the skin. It spreads slowly through the peripheral nervous system to the brain, where it causes inflammation resulting in fever and delirium. Infection in humans can be fatal, though modern vaccines are effective if taken within the incubation period of the virus.