Posted by The rabies virus is very sneaky. From the start, the virus travels along the neural pathway into the central nervous system. The virus will infect the muscle cells closest to the site of infection. This is where they can replicate without being “seen” by the infected immune system. They replicate, and once there is enough of the virus it begins to bind to the acetylcholine receptors at the neuromuscular junction. Then, they hide and work their way up to the brain. After the brain is infected, the virus moves into the peripheral and autonomic nervous systems, and eventually to the salivary glands, where the virus is signaled that it is ready to be transmitted to the next host. Rabies is sneaky, because once onset, it can be mistaken for other diseases in the early stages. However, almost always is the disease fatal once symptoms arise. The virus is transmitted by saliva, and Rabies virus belongs to the order Mononegaviruses, viruses with a nonsegmental, negative-stranded RNA genomes. Within this group, viruses with a distinct “bullet” shape are classified in the Rhabditida family. The time between the bite and the appearance of symptoms is called the incubation period and it may last for weeks to months. A bite by the animal during the incubation period does not carry a risk of rabies because the virus has not yet made it to the saliva. Late in the disease, after the virus has reached the brain and multiplied there to cause an inflammation of the brain, it moves from the brain to the salivary glands and saliva. The reason there is so much variation in the time between exposure and the onset of the disease is that many factors come into play, including the site of the exposure, the type of rabies virus, and any immunity in the animal or person exposed.
I chose to draw a diagram of the virus pathway to the brain. The virus is so unique in its incubation period, how it affects your cells and your brain, and then the symptoms, which include flu-like symptoms, discomfort or a prickling or itching sensation at the site of the bite, progressing within days to acute symptoms of cerebral dysfunction, anxiety, confusion, and agitation. As the disease progresses, the person may experience delirium, abnormal behavior, hallucinations, hydrophobia. I decided to show the structure of the virus as well, as it has that unique “bullet” shape.
Despite this disease being eradicated in dogs in the United States, Africa, China and India, a combines 60,000 people die every year from Rabies. WHO would like to see rabies eradicated by the year 2030.
There is a vaccine for this disease, and The Rabies human diploid cell vaccine is used to protect people who have been bitten by animals (post-exposure) or otherwise may be exposed to the rabies virus (pre-exposure). This vaccine works by exposing you to a small dose of the virus, which causes the body to develop immunity to the disease. This works because as I explained above, the virus hides in your cells and your immune system does not recognize it as the rabies virus.
In My drawing/diagram. I demonstrated in steps where the virus goes. The circular bubble is where the virus binds to the Nicotinic acetylcholine receptors at the neuromuscular junction. The virus travels up the Dorsal Root Ganglion (in my diagram) via retrograde fast axonal transport. Then the replication of the virus and rapid movement towards the brain.
Crowcroft, N., & Thampi, N. (2015). The prevention and management of rabies. BMJ: British Medical Journal, 350. Retrieved August 4, 2021, from https://www.jstor.org/stable/26517874
Botting, J. (2015). Rabies. In Botting R. (Ed.), Animals and Medicine: The Contribution of Animal Experiments to the Control of Disease (pp. 17-28). Cambridge, UK: Open Book. Retrieved August 4, 2021, from http://www.jstor.org/stable/j.ctt15m7ng5.7
Goldrick, B. (2005). Emerging Infections: Human Rabies. The American Journal of Nursing, 105(5), 31-34. Retrieved August 4, 2021, from http://www.jstor.org/stable/29745727
The rabies virus is typically transmitted by the saliva of an infected host, often in the form of a bite. At the point of the bite, the “incubation” period has begun. This is the period between contracting the virus and showing symptoms. Interestingly, this virus is not transmittable during the incubation period of the host. This is because the virus must travel through the dorsal root ganglion, up the spinal cord and into the brain before symptoms arise. Only after that does the virus travel through salivary glands and become transmittable. Because of this path, and the immune status of the host, the incubation period varies greatly.
The Rabies virus is largely controlled globally, but fatalities amount to around 60,000 humans per year. Use of vaccination is one means of resisting the spread of rabies. Someone can use a vaccine before anticipated exposure or after exposure to prevent acute disease. It is the goal of the World Health Organization to fully eradicate the rabies virus by 2030.