Rabies affects humans by infecting the central nervous system, leading to severe brain inflammation (encephalitis) and almost always resulting in death once symptoms appear
How Rabies Affects Humans
- Transmission: Rabies virus (RABV) enters the body usually through the bite of an infected animal, with the virus present in the animal's saliva. It can also enter through scratches or contact with mucous membranes
- Incubation Period: After infection, the virus travels slowly along peripheral nerves toward the central nervous system (brain and spinal cord). This incubation period can last from days to weeks, sometimes months or even years, during which no symptoms are present
- Prodromal Phase: When the virus reaches the nervous system, early symptoms appear, including flu-like signs such as fever, headache, malaise, and tingling or numbness at the bite site. The immune system begins to respond, but no effective treatment exists once symptoms start
- Neurological Phase: Rabies causes two main forms of neurological symptoms:
- Furious Rabies: Characterized by hyperactivity, agitation, hallucinations, seizures, aggression, confusion, hydrophobia (fear of water due to painful throat spasms), aerophobia (fear of drafts), and excessive saliva production ("foaming at the mouth"). This form usually lasts a few days to a week before death occurs
* **Paralytic Rabies:** Accounts for about 20% of cases, with gradual muscle weakness and paralysis starting at the bite site and spreading. This form progresses more slowly and may be misdiagnosed. Death results after coma develops
- Final Stage: The disease progresses to coma and death, typically due to respiratory failure, seizures, or paralysis. Rabies is almost always fatal once clinical symptoms develop
Summary of Symptoms
- Initial: Fever, headache, malaise, tingling or numbness at bite site
- Neurological: Restlessness, confusion, hallucinations, muscle spasms, seizures, hydrophobia, paralysis
- Terminal: Coma and death
Rabies causes about 59,000 deaths worldwide annually, mostly in rural Asia and Africa. In the U.S., human cases are rare due to effective post-exposure vaccination
Prevention and Treatment
Rabies is preventable if treatment (wound cleaning, rabies vaccine, and immune globulin) is given promptly after exposure, before symptoms start
. In summary, rabies affects humans by causing progressive neurological damage leading to severe brain dysfunction, paralysis, and death if untreated after symptoms appear
