Rabies is caused by a virus known as the rabies virus. According to the Centers for Disease Control and Prevention (CDC), this virus belongs to a family of viruses known as the Rhabdoviridae family.
Rhabdoviruses, including the rabies virus, are classified as being part of the Mononegavirales order of viruses, according to the CDC. The CDC states that Rhabdoviruses have a bullet-like shape and are approximately 180 nm long and 75 nm wide. According to the Cleveland clinic, the rabies virus usually infects animals, but it can be passed to humans if infected animal saliva gets into a wound or into a person's mouth or eyes.