From A Small Fever To Irreversible Paralysis: Understanding Polio

Exploring the neurology of Poliomyelitis and its impact on the nervous system

“Never underestimate the power of dreams and the influence of the human spirit” — Wilma Rudolph.

At the age of four, Wilma Rudolph was diagnosed with polio, and doctors told her that she could never walk again. She grew up to become the fastest woman on Earth at twenty years old and went ahead to win three gold medals during the 1960 Summer Olympics.

Communication plays a critical role in relationships, with 87% of Americans stating it is a factor fundamental to success.

When the main line for communication doesn’t function properly, much like a relationship, the body’s systems crumble.

That is exactly what happens in polio.

Polio is a neurotropic virus, meaning it attacks neural tissue and the nervous system. It can be transmitted from person to person primarily through contaminated food or water, and less commonly through sneezing or coughing. Polio is the common name for “poliomyelitis.”

There are three main classified types of the virus with different symptoms.

1. Abortive Polio has symptoms similar to the flu, lasting 2–3 days, with symptoms such as fever, nausea, muscle aches, and vomiting. In comparison to the other types, this type carries the least amount of risk, yet is much more common.
2. Nonparalytic Polio has symptoms similar to abortive polio, in addition to neck pain, stiffness, and muscle weakness. A second phase of symptoms may follow, characterized by slower reflexes and muscle weakness. It is more life-threatening than abortive polio and impacts a smaller portion of the population.
3. Paralytic polio progresses with much more severe symptoms, such as sensitivity, muscle spasms, and paralysis in one limb. It is the most severe of the three and is the least occurring, affecting less than 1% of cases.

Although these three are the types that have symptoms, around 70% to 90% of the population that contracts polio doesn’t experience most of the common symptoms. It may seem they are asymptomatic, but they can still pass it on to those around them, making them carriers.

Ultimately, understanding how polio works helps us understand how vaccines work, why there are such varied symptoms, and how the damage to the nervous system can completely transform the nature of the virus.

However, as evidenced by the life of Wilma Rudolph, having polio did not set the boundaries of what her human body could accomplish. It doesn’t matter if the body’s communication is disrupted; the desire to transcend beyond challenges and difficulty will always persist.

In her case, it proves that although polio can disrupt neural communication, it cannot stifle human perseverance.

How The Virus Enters

Unlike most infectious agents, like bacteria, viruses are not considered alive. This is mainly because they cannot replicate independently and require a host cell to replicate their DNA and further reproduce.

When a virus enters the body, it spreads through the bloodstream or nervous system and attaches itself to host cells.

By attaching to a host cell, a virus can insert proteins and DNA or RNA for replication and reproduction within the host cells. Polio inserts RNA.

Viruses completely hijack the host cell, influencing what processes are going on. Typically, the cell contributes to the body’s health by transcribing and translating DNA. These functions allow for DNA to be turned into RNA and then into proteins and carry out bodily functions or messages.

Polio, specifically, replicates itself in the intestines and throat before going into the nervous system.

After the replication process takes place in the intestinal wall and the pharynx, the virus will not necessarily move beyond these organs. In such circumstances, Poliomyelitis might result in very minor or even no symptoms at all. In some other instances, Poliomyelitis becomes more serious when the virus moves out of the intestine and throat to the blood vessels.

By entering the bloodstream, the virus can travel to any part of the body, including the central nervous system. In doing so, the virus starts attacking nerve cells rather than causing general illness.

Poliomyelitis has a distinct preference for the motor neurons. These neurons play a vital role in transmitting messages from the brain to the muscles. Once the virus reaches them, it will start destroying them, making it impossible for the body to send any commands. Therefore, signals sent by the brain to the muscles cease, and muscles lose their ability to function.

Communication and Motor Neurons

However, not all the neurons within the nervous system are impacted by the poliovirus.

As stated above, the virus targets motor neurons, which are unique nerve cells responsible for transmitting impulses from the brain to muscles. These nerve cells serve as couriers by transmitting impulses to facilitate voluntary movements.

In most cases, movements are started from the brain, where there is a unique section of cells referred to as the motor cortex, responsible for movements.

When this impulse is traveling within the spinal cord, it will reach the motor neurons, whose role is to serve as the connection between the nervous system and muscles. Normally, millions of these impulses are sent and can travel at hundreds of miles per hour. These neurons will transmit the impulse towards muscle fibers.

At the neuromuscular junction, where the motor neurons end and come into contact with muscle fibers, the electric impulses are changed into chemical impulses due to the formation of acetylcholine (ACh).

After the production of this chemical, it will react to receptors within the muscle fibers and trigger internal activities that cause muscle contraction due to protein interactions.

Apart from the above process of initiating movements, other parts of the brain may be involved in fine-tuning movement. Examples of these parts include the cerebellum, which helps in coordinating movements, and the basal ganglia, which help regulate movement intensity and initiation.

In the case of a polio infection, this mechanism stops functioning properly.

Polio affects motor neurons within the nervous system and damages them. What makes these neurons especially vulnerable to damage is their lack of regenerative capability. In most cases, after being damaged, neurons cannot be restored.

When there is further damage to motor neurons, the link between the brain and muscles becomes increasingly weaker.

There may be some communication, but it does not occur properly anymore. In the long run, this will continuously degrade communication till it does not occur at all. While the muscles will be anatomically healthy, without signals sent by the nervous system, they cannot perform any function.

It is this breakdown in communication that causes paralysis. Paralysis is not triggered due to muscle injury, but because of a malfunction of the signaling system within the body. An initial viral infection has caused serious issues in one of the core body functions, the possibility of movement.

Vaccination and Prevention

The best way to understand Poliomyelitis is by considering its prevention.

The word “vaccine” comes from the Latin word for cow, or “vacca”. This is because Edward Jenner, an English physician, used cowpox in the first vaccine. He observed that smallpox, a deadly virus, was not contracted by individuals who had cowpox, which was less deadly. He conducted an experiment by injecting the pus from a cow with cowpox into his servant. They contracted cowpox, and then later, he exposed them to smallpox. The servant did not contract the disease, showing that exposure to cowpox reduced the chance of contracting smallpox.

Vaccines enable the body to develop resistance to viruses, and Jenner’s experiment shows just this. In the case of polio, this implies that the virus is stopped from spreading within the body and prevents motor neurons from being hijacked. It enables the body to retain the ability to communicate signals, which is necessary for movement.

Vaccines are specifically important because of the serious impact of the disease on the nervous system, making it irreversible most of the time.

However, in some cases, not all neurons are completely affected. The body demonstrates this remarkable ability to adapt and partially recover through “neuroplasticity”. The remaining neurons sprout new fibers, initiating recovery. These fibers connect with muscles that have lost their original nerve supply. Usually, this process can take months or even years.

The benefits of immunization and prevention extend beyond just ensuring safety; they are also a way of protecting whole societies.

A high rate of vaccinations among people reduces the incidence of poliovirus in a community. The concept of herd immunity plays a role in ensuring that there are no cases of polio among individuals who cannot be immunized.

Vaccines have taken us far in terms of polio prevention, leaving little to no cases of polio today.

Various international organizations, including the WHO, have increased their attempts at global vaccinations, which have resulted in a significant drop in polio rates within the last few decades.

These instances illustrate how crucial prevention is in ensuring proper communication between different parts of the nervous system. The effectiveness of vaccines lies in the ability to prevent the poliovirus from infecting motor neurons. It becomes clear how important vaccines are in safeguarding the nervous system and preventing infections from destroying the communication network within the body.

In the end, poliomyelitis teaches the importance of communication in the body and the disastrous results when it stops working.

The case of Wilma Rudolph teaches an additional lesson. Her diagnosis didn’t limit her future, but instead, she showed determination and found support. Her hope and resilience took her closer to achieving her dreams, no matter how impossible they seemed. Just as the body relies on persistence, individuals can do the same and overcome adversity. Polio was the starting point, but look at where it led her.

Works Cited

Centers for Disease Control and Prevention. (2024, May 9). About polio in the United States. https://www.cdc.gov/polio/index.html

Discover Magazine. (n.d.). Numbers: The nervous system — from 268 mph signals to trillions of synapses. https://www.discovermagazine.com/numbers-the-nervous-system-from-268-mph-signals-to-trillions-of-synapses-2148

Langer, N. (2026, March 6). Wilma Rudolph, Olympic sprint champion, dies at 54. The New York Times. https://www.nytimes.com/2026/03/06/sports/wilma-rudolph-dead.html

Mayo Clinic. (2024, June 20). Polio — Symptoms and causes. https://www.mayoclinic.org/diseases-conditions/polio/symptoms-causes/syc-20376512

National Institute of Neurological Disorders and Stroke. (n.d.). Brain physiology in polio survivors. https://www.ninds.nih.gov/health-information/clinical-trials/brain-physiology-polio-survivors

Pitts, M. K., & Others. (2024). Poliomyelitis. In StatPearls. NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK558944/

World Health Organization. (2025, April 2). Poliomyelitis. https://www.who.int/health-topics/poliomyelitis#tab=tab_1

YouGov. (2025, February 7). What do Americans think are the keys to a successful relationship?https://www.yougov.com/en-us/articles/51546-what-do-americans-think-are-the-keys-to-a-successful-relationship

Written by Yashica Vidwani