Why is there so much fear of polio? What is Polio?
Polio is a viral disease caused by poliovirus. It affects the nervous system and can cause paralysis, permanent disability, and even death. There are two types of polio virus: wild-type polio (WPV) and vaccine-derived poliovirus (VDPV). Wild-type polio is naturally occurring and occurs in three separate forms: 1) Type I—causes paralytic cases; 2) Type II—causes benign cases; and 3) Type III—is the rarest type of polio and causes no symptoms at all. Vaccine-derived polio was developed after vaccination programs began in 1955, but since then, it’s been discovered that certain strains of VDPV have mutated and become able to spread throughout the population. These mutations occur when viruses mutate over time and are not considered natural. A few examples of these mutations are Sabin strain (used for oral vaccines), Mahoney strain (used for injectable vaccines), and Saukett strain (used for both oral and injectable vaccines). The wild-type polio virus has never been detected outside of Africa, Asia, and South America.
The first case of polio was documented in 1595 in Italy. In 1854, Dr. James Carroll published his book “Practical Treatise on Poliomyelitis” where he described the different symptoms associated with polio. He stated that if a child did not receive treatment, they would experience pain and numbness along with weakness and stiffness in their legs. Most importantly, he said that about 10% of children who were infected by polio did not recover completely and may die. By the 1930s, polio had become a major epidemic that was killing hundreds of thousands of people each year. In 1952, Jonas Salk created the world’s first polio vaccine and successfully tested it on humans. After the success of the Salk vaccine, the United States started administering the vaccine to children and the number of polio cases dropped significantly. Since then, many countries, including Canada, Australia, Japan, the UK, India, Pakistan, Nigeria, and Ethiopia have been successful in eradicating polio. However, in 2014, the World Health Organization reported that there were still approximately 350,000 cases of polio around the globe.
In the 1950s, scientists noticed that polio was becoming less prevalent in those countries that were actively vaccinating their children. This led them to believe that if children were vaccinated early enough, they would not get sick. If this hypothesis was true, then polio could be contained until a cure was developed. Unfortunately, the opposite occurred. Children who were given the vaccine later in their lives experienced more severe side effects than those who received the vaccine earlier. This led to the idea that polio was being passed down genetically and was actually becoming more dangerous. It seemed that there was no way to stop polio, and some researchers thought that it might be impossible to eradicate.
In 1960, Dr. Albert Sabin developed a live attenuated virus vaccine which was safer and easier for children to handle than previous vaccines. His research showed that the live attenuated vaccine was 95% effective in protecting against polio. This meant that there was only 5% chance that
Poliovirus was discovered in 1953 by Dr. Jonas Salk and Dr. Albert Sabin
Polio virus was first isolated in 1955, and its cause was identified in 1957. In 1961, the vaccine was developed and distributed to over 400 million people.
There were only 2 cases of wild poliomyelitis reported in the United States between 1949 and 1964.
Poliovirus is a member of the Picornaviridae family, which includes Hepatitus A and B, Rhinovirus, Coronavirus, and Enterovirus. These viruses have been responsible for millions of deaths worldwide.
Poliovirus attacks the central nervous system by damaging nerve cells. Symptoms of the disease may include muscle weakness, paralysis, and death. Most patients recover completely after weeks or months. However, some never fully recover and suffer permanent paralysis.
There are three types of poliovirus: 1) type 1 (Sabin), 2) type 2 (Mahoney), and 3) type 3 (MEF-1). Type 1 and 2 are attenuated (less virulent) strains, while type 3 is highly virulent.
Poliovirus is transmitted via oral secretions, nasal discharges, feces, urine, semen, respiratory droplets, or contact with contaminated objects.
Vaccination is the best way to protect against poliovirus infection. All children should receive at least two doses of the vaccine before they start school. Booster shots should be administered throughout childhood.
Polio is still endemic in certain regions of the world including India, Pakistan, Nigeria, Afghanistan, Somalia, Chad, Cameroon, Indonesia, Yemen, and Ethiopia.
Wild poliovirus exists in many parts of Africa and Asia, and the virus has recently reemerged in southern Russia.
Polio is not a contagious disease; however, infected individuals can spread the virus by coughing and sneezing, and fecal matter can contaminate surfaces and objects.
To prevent the spread of the disease, hand washing and proper disposal of excreta are critical. Vaccinated individuals who become ill should not return to work until 24 hours after their fever subsides.
Polio is treatable and curable; however, complications can occur if treatment is delayed.
The CDC estimates that between 200,000 and 500,000 people die each year from polio.