As part of the vaccination quandary fueled by inaccurate information, Polio has made a worldwide comeback affecting millions of individuals around the world.  Officially called poliomyelitis, or infantile paralysis, polio is an acute, viral, infectious disease spread from person to person, primarily via the fecal-oral route.

The Disease

The disease is an inflammation of the spinal cord’s gray matter, but a severe infection can extend into the brainstem and even higher structures, resulting in polioencephalitis, producing apnea that requires mechanical assistance to breathe. Although approximately 90% of polio infections cause no symptoms at all, affected individuals can exhibit a range of symptoms if the virus enters the blood stream. In about 1% of cases, the virus enters the central nervous system, preferentially infecting and destroying motor neurons, leading to muscle weakness and acute flaccid paralysis.

Various types of paralysis may occur, depending on the specific nerves involved. Spinal polio is the most common form, characterized by asymmetric paralysis that most often involves the legs.  Bulbar polio leads to weakness of muscles innervated by cranial nerves. Bulbospinal polio is a combination of bulbar and spinal paralysis.

Poliomyelitis was first recognized as a distinct condition by Jakob Heine, a German Orthopedist, in 1840.  His findings were the first medical account of polio and, because of his work in explaining the disease it was acknowledged as a clinical entity. In 1890, Karl Oskar Medin distinguished and diagnosed  polio as an acute infection. The disorder was originally called Heine-Medin Disease for the two scientists.

A Swedish physician, Otto Ivar Wickman made a finding concerning the infectious and contagious nature of polio and published his hypothesis on the disease in Germany.  The Austrian physician Karl Landsteiner, along with Erwin Popper, discovered the poliovirus in 1909.

Polio Epidemics

 Although major polio epidemics were unknown before the late 19th century, polio became one of the most dreaded childhood diseases of the 20th century. Polio epidemics have crippled thousands of people, mostly young children. However, the disease has caused paralysis and death for much of human history. It had existed quietly for thousands of years as an endemic pathogen until the 1880s when the major epidemics began to occur in Europe. Soon after that, widespread epidemics also appeared in the United States.

Polio was probably  feared most in the first half of the 20th century, when mass urbanization led to sporadic, localized epidemics in the US.  The first official epidemic was announced in New York in 1916, and in 1952 over 58,000 cases were reported, causing the deaths of 3,145 people and leaving another 21,269 with paralysis that ranged from mild to disabling.

Thanks to the invention of vaccines, by 1988, the USA, Canada, the UK, and much of mainland Europe was polio free. But the story was very different in other regions. There were still 125 countries - including all of Africa and Asia - where polio was endemic and continued to be a threat. At its annual meeting, the World Health Assembly - the decision-making body of the WHO – voted to launch a global polio eradication initiative (GPEI) with a target date of 2000. That date  has now passed and polio is still found in some parts of the world, despite continuing efforts to end it.

Treatment

Polio probably started B.C., as there are Egyptian hieroglyphs that show withered legs.  We can only guess at how they may have treated polio back then.  In the early 1900s people were being put in casts and on bed rest, which immobilized their limbs and caused them to wither.  In the 1920s Sister Kenny started treating polio victims, using warm, wet woolen blankets as hot packs and then slowly moving an affected limb so it would learn how to work after being paralyzed.  There was much controversy over her treatment, but it was very successful in helping children walk again.

Generally, there was no real treatment for the disease until 1928 when the iron lung was invented to assist patients in their breathing. Before that, polio patients with breathing problem would usually die because their breathing muscles did not function. While the intimidating metal contraption was certainly a life saver, for those left with permanent paralysis, it was also a life sentence. The patient was permanently encased in the air-tight metal tank in order to force their weakened lung muscles to function.

In the 1950s, Dr. Jonas Salk, an American virologist, invented a vaccine that was successful.  Salk’s approach, first attempted unsuccessfully by Maurice Brodie, also an American, in the 1930s, was to kill several strains of the virus and then inject the benign viruses into a healthy person’s bloodstream. The person’s immune system would then create antibodies designed to protect the person in case of future exposure to poliomyelitis. Salk conducted the first human trials on former polio patients and on himself and his family, and by 1953 was ready to announce his findings. This occurred on the CBS national radio network on March 25 and two days later in an article in the Journal of the American Medical Association. Dr. Salk became an immediate celebrity.  In 1954, clinical trials using the Salk vaccine and a placebo began on nearly two million American schoolchildren. In April 1955, it was announced that the vaccine was effective and safe, and a nationwide inoculation campaign began. New polio cases dropped to under 6,000 in 1957, the first year after the vaccine was widely available.

In 1962, an oral vaccine developed by the Polish-American researcher Albert Sabin became available, greatly facilitating distribution of the polio vaccine. What followed was a mass vaccination program that marked the beginning of the end for polio in the developed world.  But just when polio was on the verge of extinction, it has come back in many parts of the world. Some are places where there was no vaccination available.  In the West, lack of immunization is a factor in its resurrence.  One organization that has made a major impact on the eradication of poliomyelitis is Rotary International. Check out the video on Rotary’s efforts to eradicate Poliomyelitis.

The Hearing Loss Connection

While some sources indicate that polio has not much to do with hearing loss, others report that over the last three to four decades the incidence of acquired sensorineural hearing loss (SNHL) in children living in developed countries has fallen as a result of improved neonatal care and the widespread implementation of immunization programs.  There are indications that even non-paralytic Polio sometimes leads to hearing loss or learning abnormalities. Bachor and Karmody (2001) found that in the temporal bones of a 26-month-old white female with a paralytic syndrome clinically and pathologically identical to poliomyelitis there was a complete absence of the cochlear neurons and substantially reduced peripheral and central axons with loss of some inner hair cells but preservation of outer hair cells. They also found that Scarpa’s ganglion and the geniculate ganglion were partially atrophied and that the saccule and utricle were mildly dilated and Reissner’s membrane at  the apical turn was bulging.

In two previous audiological studies a 10-20 dB bilateral sensorineural hearing loss was found in poliomyelitis patients and a neuronal lesion was suggested.  While the jury is still out as to how prevalent hearing impairment is among polio victims, Audiologists need to be vigilant and look for hearing impairment in patients that have contracted poliomyelitis, especially in children.