Rabies is a deadly viral disease that is mainly spread by infected animals. It attacks the central nervous system and causes inflammation of the brain that is fatal once symptoms appear. Here is a look at whether the human body can naturally fight rabies without treatment:
What is rabies?
Rabies is caused by a virus in the genus Lyssavirus. It is most commonly spread through a bite from an infected animal such as a dog, bat, raccoon or fox. The rabies virus infects the central nervous system, causing disease in the brain and eventually death once symptoms appear.
The rabies virus has a bullet shape and contains ribonucleic acid (RNA) as its genetic material. It binds to and enters nerve cells, quickly reproducing and spreading to the brain via the nervous system. Eventually, it causes severe inflammation in the brain, leading to symptoms like cerebral dysfunction, anxiety, confusion, aggression, excessive salivation, difficulty swallowing, and hydrophobic spasms.
Can the human body fight off rabies without treatment?
No, the human body cannot naturally fight off a rabies infection without medical treatment. Once a person begins showing signs and symptoms of rabies, the disease is essentially 100% fatal. Even with intensive care in hospitals, there are only about dozen documented cases of people surviving clinical rabies.
This is because by the time symptoms appear, the virus has already spread through the nervous system and invaded the brain. The body’s immune system is unable to eradicate the virus at this stage. That’s why post-exposure prophylaxis, given soon after a possible rabies exposure, is critical.
How does rabies evade the immune system?
The rabies virus has evolved clever ways to evade detection and destruction by the immune system:
- Avoids triggering innate immune response – The virus binds receptors that allow it to enter nerve cells without setting off antiviral alarms.
- Inhibits immune signaling – Rabies interferes with interferon signaling which is crucial for activating immune defenses.
- Evades adaptive immunity – It is poorly immunogenic and has mechanisms to suppress antibody production.
- Crosses protective barriers – The virus moves fast via nerve endings to enter the central nervous system which is an immunoprivileged site.
- Hides in nerve cells – Resides in neurons and nerve endings where it is protected from immune surveillance and attacks.
This allows the rabies virus to stealthily spread through the body virtually undetected. By the time the immune system detects it, the virus has already caused irreversible and fatal damage.
Can vaccines help fight rabies?
Yes, rabies vaccines can prevent the disease if given in time. Rabies vaccines work by training the immune system to recognize the rabies virus and mount a response to it before exposure. This primes the body’s adaptive immunity.
There are two types of rabies vaccines:
- Pre-exposure vaccines – Given as 3 doses over 21-28 days to people at high risk such as veterinarians. It prepares immune memory and antibodies.
- Post-exposure vaccines – Given to someone potentially exposed along with rabies immune globulin. It stimulates an immune response that can stop infection before it reaches the brain if given promptly.
Vaccines do not cure or treat rabies disease once symptoms have appeared. But they work very effectively to prevent rabies when given to a healthy individual before exposure or immediately after possible contact with rabid animal saliva.
What is post-exposure prophylaxis (PEP) for rabies?
Post-exposure prophylaxis (PEP) is the immediate treatment recommended for anyone potentially exposed to rabies from an animal bite or saliva into an open wound. It consists of:
- Thoroughly cleaning the wound with soap and water to flush out as much of the virus as possible
- Rabies immune globulin – Provides antibodies against rabies to neutralize any virus at the exposure site
- Rabies vaccine – Stimulates active immunity to rabies so the body can produce its own antibodies
PEP is very effective in preventing rabies if administered promptly within 24 hours. The rabies immune globulin stops the virus before it can enter nerve endings. The vaccine stimulates immunity which can then prevent the virus from spreading to the brain.
How long does it take to show symptoms of rabies after a bite?
The rabies virus incubation period is typically 20-60 days but can vary from under a week to several years. On average it’s 1-3 months between the bite of an infected animal and onset of symptoms, according to the following rabies virus incubation periods:
- In humans – Average 1-3 months, range 10 days to 1 year
- In domestic animals – Usually 2-12 weeks
- In bats – Average 2-4 weeks
This long and variable incubation period makes it difficult to know exactly when a person was exposed based on symptom onset. That’s why PEP is recommended whenever there is reasonable suspicion of contact with rabid animal saliva into eyes, nose, mouth or a break in the skin.
What are the first symptoms of rabies in humans?
The first symptoms of rabies in humans often involve general discomfort or uneasiness. Early flu-like signs can include:
- Fever
- Headache
- Nausea
- Vomiting
- Tingling at the site of exposure
Within days, neurological symptoms arise as the virus invades the nervous system:
- Increased anxiety
- Confusion
- Agitation
- Hallucinations
- Insomnia
- Difficulty swallowing
- Excess salivation
- Avoidance of bright lights, wind, noise or water (hydrophobia)
Once symptoms begin, rabies progresses rapidly. The disease is exceptionally rare in people who receive proper post-exposure prophylaxis before any symptoms start.
Conclusion
Rabies unleashes terror in the human body – invasion of the central nervous system by a deadly virus that incites brain inflammation, cerebral dysfunction, and inevitable death. Yet with modern vaccines and immunoglobulin injections, the disease is completely preventable, even after exposure from an animal bite, as long as treatment begins before symptoms arise. While the untreated rabies virus ruthlessly destroys the brain, an early immune counterstrike triggered by vaccines and rabies antibodies can neutralize the virus and defend the nervous system from a horrific demise.