Poliomyelitis, or Polio as it is more commonly known, is a debilitating disease that affects the central nervous system (CNS) of those it infects. The infection attacks motor neurons and gradually causes paralysis and an inability to survive without life support. The term Poliomyelitis comes from the Greek terms polios and myelos, which mean “grey” and “marrow,” while the suffix itis is commonly used to describe inflammation.
What is polio?
Polio is caused by infection with the poliovirus, part of the RNA virus family, that attacks the central nervous system of the body. Specifically, the virus attacks the spinal cord and brain, and can cause total paralysis in a matter of hours. The poliovirus enters the body through the mouth and colonizes the gastrointestinal tract. While 1 in 200 infections leads to irreversible paralysis (usually in the legs), 5% – 10% of those paralyzed die when their breathing muscles become immobilized. Although it is possible to prevent polio through vaccination, the disease itself is incurable. Treatment for those who have polio is focused on reducing symptoms and complications instead of actually eradicating the poliovirus. This means it is absolutely essential to be immunized from polio before getting infected.
Where does polio come from?
The precise beginnings of polio history are still unclear. However, there are recordings as far back as the Ancient Egyptians of men and women with withered limbs, which many historians believe is a reference to polio or a polio-like disease. While Michael Underwood provided the first clinical description of the disease, describing it as “a debility of the lower extremities” in 1789, the work of Jakob Heine and Karl Medin in the second half of the 19th century led to the name Heine-Medin disease. Poor sanitation before the 20th century resulted in constant exposure to the virus and enhanced children’s immunity, but improved sanitation in the late 19th and early 20th century dramatically increased the risk of polio infection for both children and adults. Small polio epidemics started to appear in Europe and the United States around 1900, whereas large pandemic outbreaks affected Europe, the United States, Australia and New Zealand throughout the first half of the 20th century. Jonas Salk wrote polio vaccine history in 1957, when he introduced the polio vaccine. The revered polio vaccine developer is credited with preventing many thousands of cases of crippling illness and saving thousands of lives. Today, polio is very rare in most parts of the world thanks to aggressive vaccination programs.
How is polio transmitted?
Polio is transmitted from human to human, that is, via the fecal-oral or the oral-oral route. The poliovirus is primarily found in human fecal matter. Hence, the disease is usually spread by ingesting contaminated food or water. In rare cases, such as in areas with good sanitation and hygiene, polio is spread from mouth to mouth. Individuals with weakened immune systems and those in generally poor health are at a particularly high risk of infection. The incubation period is usually 6 – 20 days, with a maximum range of 3 – 35 days. Polio is most infectious between 7 and 10 days after the appearance of symptoms, though transmission is possible as long as the virus remains in the saliva or feces.
What are polio symptoms?
The vast majority of people infected with the poliovirus does not get ill and never know they have been infected. Some people develop mild, flu-like symptoms which are signs of nonparalytic polio. These symptoms last 1 – 10 days and can include coughing, a sore throat, fever, vomiting, and general fatigue. In rare cases, poliovirus infection leads to paralytic polio which starts with symptoms similar to those of nonparalytic polio. However, within a week, more severe symptoms will appear, such as the loss of reflexes, severe muscle pain or weakness, as well as loose and floppy weakness. There are three types of paralytic polio, based on the body part that is affected: spinal polio (spinal cord), bulbar polio (brainstem) and bulbospinal (both). After having polio, some people suffer from post-polio syndrome which is accompanied by symptoms like muscle pain and weakness, general fatigue and exhaustion after little activity, breathing and swallowing problems, sleep disorders, cognitive problems and depression.
What is the polio vaccine?
Public sanitation and personal hygiene are two of the most effective ways to prevent the poliovirus from spreading. Most first-world countries, and an increasing number of third-world countries, are able to prevent the spread of polio through these methods alone. However, the polio vaccine, also known as the Inactivated Poliovirus Vaccine (IPV) is an intramuscular or subcutaneous injection given in the arm or leg. The polio vaccine is mandatory in almost all industrialized nations and is becoming increasingly available in developing nations thanks to charitable organizations. The vaccine itself is typically given to children at four separate times. The first two are usually received at two and four months after birth, with a third dose given at least two months after the second dose and before the child is 18 months old. A fourth and final shot is given around preschool or kindergarten age, which is usually around 4 – 6 years of age. For adults who have never received a polio shot, a similar timeframe of 2 months between the first three doses and a fourth dose 6 – 12 months later is common. The polio vaccine itself is more than 99% effective after three doses, and the fourth dose reduces the risk almost to zero.
What are the polio vaccine side effects?
Although most side effects are not dangerous, they should still be watched. Individuals with weak immune systems or in generally poor health are at particular risk for side effects. The most common side effects include dizziness, rapid heartbeat, throat swelling, and weakness or difficulty breathing. If there are any signs of side effects, be sure to visit the doctor or emergency room if these symptoms do not quickly subside.
Who should not get the polio vaccine?
Since polio is incurable if contracted, it is highly advisable for almost everyone to receive the polio vaccine. However, there are some small portions of the population that are at a higher risk of having severe side effects, and these risks must be weighed against the risk of contracting the polio virus itself. The polio vaccine contains the antibiotics streptomycin, neomycin, and polymyxin B; thus people allergic to any of these components should not get the polio vaccine. Anyone who had a severe allergic reaction to a previous polio shot should not get another one. People who are ill at the time of the scheduled vaccination should wait until they fully recover. Before making any decisions for yourself or your loved ones, be sure to speak with a physician.