The causative agent of rabies is the rabies virus, or RV, a negative-stranded ribonucleic virus of the rhabdovirus family, according to the National Institutes of Health. The virus causes rabies by invading and attaching itself to the central nervous system.
Rabies is a disease that normally exists in animals but can infect humans. The mode of infection to humans is usually through the bite of an infected animal. NIH reports that 70,000 people die from rabies worldwide every year. According to NIH, the symptoms of rabies in animals are either aggression and viciousness or tiredness and weakness. In humans, the symptoms include fever, headache, fatigue, confusion, hallucinations and paralysis.