Polio is a notorious illness most prevalent in the first half of the 1900s. Also known as poliomyelitis, it is caused by a highly infectious virus that can lead to a host of severe and potentially fatal symptoms.
In around 95% of cases, however, polio produces no symptoms, according to Kids Health. In the 4% to 8% where it is symptomatic, the disease appears in 3 different forms: the milder abortive polio, more serious nonparalytic polio and the severe paralytic form.
Due to the discovery of a vaccine against the illness in 1955, the number of cases has fallen dramatically since the mid-20th century. In most parts of the western world, polio is thought to have been virtually eradicated. In Nigeria, Afghanistan, Pakistan and India, however, it continues to pose a serious threat, the NHS reports.
What are the symptoms?
Most people who become infected with the virus, suffer from its mildest form (abortive polio). The symptoms for this type of polio usually appear between 3 and 21 days after infection and are flu-like. The sufferer may experience:
- A sore throat
- High temperature or fever
- Nausea and vomiting
- Diarrhoea or constipation
Nonparalytic polio patients may have neurological symptoms too, such as sensitivity to light or neck stiffness.
People suffering from these two types of polio usually make a full recovery. The rarest and most serious ‘paralytic’ form, however, can cause permanent muscle paralysis and even death.
The condition damages the nerve cells in the body. Chances of survival depend on which muscles in the body have been damaged and to what extent. If, for instance, the sufferer’s breathing muscles become paralysed, he or she will no longer to able to draw air normally.
The NHS also points out that people who have suffered from polio in the past can develop a newly discovered condition called post-polio syndrome (PPS). Around 20 to 66% of former patients are thought to contract the illness between 10 and 40 years after the initial bout.
PPS can cause muscle weakness, fatigue, pain, swallowing problems and heightened sensitivity to the cold.
What causes it?
Polio is caused by the enterovirus, which thrives in the gastrointestinal tract before moving on to attack the nervous system through the bloodstream. It is spread through ingestion of matter contaminated by a sufferer’s faeces. This is why the disease is more likely to spread in countries with poor sanitation. Not washing your hands after using the bathroom or drinking contaminated water, for instance, can lead to infection.
The exact cause of PPS is still unknown, although one theory suggests that the polio virus can lay dormant in the nervous system for years and years until it is somehow reactivated.
How is it treated?
There is no known cure for polio. The vaccine introduced in 1955 has seen a drastic decline in the number of cases and making sure all children are vaccinated remains a top priority in most countries.
In the U.S. it is recommended that children receive 4 doses of the vaccine between the ages of 2 months and 6 years.
Those who suffer from polio will find that their treatment focuses on easing symptoms, preventing complications and speeding up recovery.
Images: Wikimedia CommonsTags: causes symptoms