Polio

Overview

Polio is a disease caused by a poliovirus that primary affects the nerves in the spinal cord or brain stem. Most people experience mild symptoms or none at all, but in some, when polio is at its most severe, a person may become paralyzed, or even death. This is called poliomyelitis.

The poliovirus is known as wild poliovirus type 1, 2, and 3 (WPV1, WPV2, and WPV3). Types 2 and 3 of wild polio have been eradicated and are extinct, whereas type 1 of wild polio remains limited to a few regions worldwide. Paralysis is most likely to result from type 1 polio.

The way polio affects your body can vary based on the location of the virus’s multiply and attack. Types of polio include:

• Abortive poliomyelitis: Flu-like and gastrointestinal symptoms are caused by abortive poliomyelitis. It doesn’t cause long-term problems and only lasts a few days.
• Non-paralytic poliomyelitis: Swelling around the brain called aseptic meningitis can result from non-paralytic poliomyelitis. It may need you to stay in the hospital and has more symptoms than abortive poliomyelitis.
• Paralytic poliomyelitis: When the poliovirus attacks your brain and spinal cord, it results in paralytic poliomyelitis. The muscles that control your breathing, speech, swallowing, and limb movement can become paralyzed. Spinal polio or bulbar polio are the terms used to describe the areas of your body affected. Bulbospinal polio is the combination of spinal and bulbar polio.
• Polioencephalitis: The rare kind of polio that primarily affects newborns is called polioencephalitis. This results to brain edema.
• Post-polio syndrome: Post-polio syndrome occurs when polio symptoms recur years after an initial infection.

In recent years, just a small percentage of cases have occurred globally due to widespread immunization campaigns. However, poliovirus still spreads in places where vaccination rates are poor.

An additional dose of the inactivated poliovirus vaccine (IPV) is advised for vaccinated adults who intend to travel to a region where polio is currently spreading. After a booster, immunity is permanent.

Symptoms

Most poliovirus-infected individuals—between 70% and 95%—don’t show any symptoms. The majority of patients exhibiting symptoms have abortive poliomyelitis, which is the mildest type and causes flu-like and gastrointestinal symptoms. The most severe symptoms of paralytic polio include paralysis.

• Abortive polio: Abortive poliomyelitis is a mild type of the disease that affects about 5% of poliovirus-positive individuals. This results in two to three days of flu-like symptoms. Among them are:
  • Fever
  • Headache
  • Loss of appetite
  • Muscle pain
  • Nausea and vomiting.
  • Sore throat
  • Stomachache
• Nonparalytic polio: About 1% of people who contract the disease develop nonparalytic polio, a more severe form of the disease. It is not a paralysis-causing condition, although it does persist longer than a few days. The following are examples of nonparalytic polio symptoms in addition to more intense flu-like symptoms:
  • Pain at the neck, arms, or legs.
  • Stiffness of the neck, arms, or legs.
  • Severe headache.
  • Photophobia or light sensitivity.

Before a second phase of symptoms begins, a person may appear to be improving for a few days. Alternatively, a second phase of symptoms may follow. Among these indications are:

• Decreased reflexes
• Muscle weakness
• Stiffness of the spine and neck

• Paralytic polio: It is uncommon for the disease to manifest in its most severe form. The disease starts similarly to nonparalytic polio. However, it develops into more serious symptoms and indicators, such as:
  • Extreme sensitive to touch
  • Muscles spasms or twitching
  • Muscles weakness that progress to a limp paralysis
  • Severe pain
  • Tingling or pricking sensations
  • Paralysis of the respiratory muscles
  • Difficulty swallowing
• Polioencephalitis: Polioencephalitis symptoms can occur alone or in conjunction with flu-like symptoms. Among the indications are:
  • Extreme fatigue.
  • Anxiety or difficulty in focusing.
  • Seizures.
• Post-polio syndrome: The appearance of new signs or symptoms or a worsening of current problems are indicative of post-polio syndrome. This typically occurs decades after contracting polio. A few typical indications and symptoms are:
  • Increasing discomfort and weakening in the muscles or joints
  • Muscle wasting
  • Breathing or swallowing problems
  • Sleep-related breathing disorders or sleep apnea
  • Lowered tolerance of cold temperatures

Polio shares many of the same signs and symptoms as other viral infections which affect the neurological system. Obtaining a prompt and correct diagnosis is crucial.

If you have ever had polio, visit your healthcare provider if you experience any new or worsening symptoms.

Causes

The poliovirus is the cause of polio. It primarily attacks the nerve cells that regulate muscular action in the brain stem and spinal cord. Sensation-controlling nerve cells are usually unaffected.

The wild-type poliovirus, though rare, has been largely eradicated in most countries. However, the predominant source of polio infections globally is now the vaccine-derived poliovirus (VDPV), which arises from the weakened strain of the virus used in oral vaccines. These vaccines do not typically cause polio in those who receive them, but areas with low vaccination rates can foster the emergence of VDPV.

The weakened virus in oral vaccines can still spread, especially in communities with insufficient vaccination coverage. When a significant portion of the population remains unvaccinated, the virus may persist and mutate, potentially acquiring characteristics similar to the wild-type virus.

Poliovirus transmission occurs through various means, including respiratory droplets from sneezing or coughing, as well as through fecal matter. The virus is highly contagious, easily spreading through oral contact and contaminated surfaces. Proper hygiene practices, such as handwashing, are crucial in preventing its transmission.

Water contaminated with poliovirus-carrying excrement may also contain the virus. swimming in water that has been contaminated. When someone with diarrhea swims in water, the water can get contaminated.

Risk factors

The following risk factors for polio may include:

• Children who are under 5 years old
• Stay or visit a place with inadequate sanitation.
• Stay or visit a region where polio hasn’t been eradicated.
• Unvaccinated.