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84-413: In 1937, Australia faced a poliomyelitis (polio) epidemic. At the time, iron lungs provided one of the main methods of treating the "paralytic breathing failures" that were a complication of the illness. Although tank respirators had been developed earlier, the iron lung itself was still fairly new, having been designed by Philip Drinker and Louis Agassiz Shaw in 1928. Their design, which became known as

168-673: A normal immune system , a poliovirus infection is asymptomatic . In about 25% of cases, the infection produces minor symptoms which may include sore throat and low fever. These symptoms are temporary and full recovery occurs within one or two weeks. In about 1 percent of infections the virus can migrate from the gastrointestinal tract into the central nervous system (CNS). Most patients with CNS involvement develop nonparalytic aseptic meningitis , with symptoms of headache, neck, back, abdominal and extremity pain, fever, vomiting, stomach pain, lethargy , and irritability. About one to five in 1,000 cases progress to paralytic disease, in which

252-518: A "Drinker's" or, due to its construction, an "iron lung", proved to be an effective means of prolonging the life of patients with poliomyelitis – although the first person to be treated in the ventilator died after two days from cardiac failure possibly related to pneumonia , the second patient recovered after spending two weeks in the machine. However in Australia, the widespread use of the Drinkers

336-537: A few significantly enlarged motor neurons doing work previously performed by as many as four or five units: a single motor neuron that once controlled 200 muscle cells might control 800 to 1000 cells. Other mechanisms that occur during the rehabilitation phase, and contribute to muscle strength restoration, include myofiber hypertrophy  – enlargement of muscle fibers through exercise and activity – and transformation of type II muscle fibers to type I muscle fibers . In addition to these physiological processes,

420-516: A few weeks for the pair to create their own iron lung, which they named the "Both portable cabinet respirator". Unlike the Drinker's machine, the Both respirator was made from plywood (even though it continued to be referred to as an "iron" lung), and this both kept the price down and made it more portable. The Both device cost only £100, was portable due to its light weight and the addition of wheels, and

504-742: A live, attenuated virus. It was produced by the repeated passage of the virus through nonhuman cells at sub physiological temperatures. The attenuated poliovirus in the Sabin vaccine replicates very efficiently in the gut, the primary site of wild poliovirus infection and replication, but the vaccine strain is unable to replicate efficiently within nervous system tissue. A single dose of Sabin's trivalent OPV produces immunity to all three poliovirus serotypes in about 50 percent of recipients. Three doses of OPV produce protective antibody to all three poliovirus types in more than 95 percent of recipients. Human trials of Sabin's vaccine began in 1957, and in 1958, it

588-450: A local inflammatory response . In most cases, this causes a self-limiting inflammation of the meninges , the layers of tissue surrounding the brain , which is known as nonparalytic aseptic meningitis. Penetration of the CNS provides no known benefit to the virus, and is quite possibly an incidental deviation of a normal gastrointestinal infection. The mechanisms by which poliovirus spreads to

672-477: A neuromuscular blocking agent that induces flaccid paralysis. This poison binds to the acetylcholine (ACh) receptors on the muscle, blocking them from binding to ACh. As a result, ACh accumulates within the neuromuscular junction, but since ACh cannot bind to the receptors on the muscle, the muscle cannot be stimulated. This poison must enter the bloodstream for it to work. If curare affects the respiratory muscles, then its effects can become life-threatening, placing

756-444: A nutritious diet. Treatment of polio often requires long-term rehabilitation, including occupational therapy , physical therapy , braces, corrective shoes and, in some cases, orthopedic surgery . Portable ventilators may be required to support breathing. Historically, a noninvasive, negative-pressure ventilator, more commonly called an iron lung , was used to artificially maintain respiration during an acute polio infection until

840-456: A permanent residual impairment after recovery from the acute illness, and both overuse and disuse of neurons. PPS is a slow, progressive disease, and there is no specific treatment for it. Post-polio syndrome is not an infectious process, and persons experiencing the syndrome do not shed poliovirus. Paralysis, length differences and deformations of the lower extremities can lead to a hindrance when walking with compensation mechanisms that lead to

924-553: A person could breathe independently (generally about one to two weeks). The use of iron lungs is largely obsolete in modern medicine as more modern breathing therapies have been developed and due to the eradication of polio in most of the world. Other historical treatments for polio include hydrotherapy , electrotherapy , massage and passive motion exercises, and surgical treatments, such as tendon lengthening and nerve grafting. Patients with abortive polio infections recover completely. In those who develop only aseptic meningitis,

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1008-451: A proportion of cases more severe symptoms develop such as headache , neck stiffness, and paresthesia . These symptoms usually pass within one or two weeks. A less common symptom is permanent paralysis , and possible death in extreme cases. Years after recovery, post-polio syndrome may occur, with a slow development of muscle weakness similar to what the person had during the initial infection. Polio occurs naturally only in humans. It

1092-547: A request for an iron lung to help treat a young patient residing in a country hospital. Responding to the call, Both hired a workshop and assembled one of his designs within 24 hours, and the Both respirator was able to quickly gain the approval of the London County Council. Subsequently, he built more of the respirators during his stay, and one was sent to the Nuffield Department of Anaesthetics at

1176-457: A severe impairment of the gait pattern. In order to be able to stand and walk safely and to improve the gait pattern, orthotics can be included in the therapy concept. Today, modern materials and functional elements enable the orthosis to be specifically adapted to the requirements resulting from the patient's gait. Mechanical stance phase control knee joints may secure the knee joint in the early stance phases and release again for knee flexion when

1260-445: A toxin that blocks the release of acetylcholine . Botulism toxin blocks the exocytosis of presynaptic vesicles containing acetylcholine (ACh). When this occurs, the muscles are unable to contract. Other symptoms associated with infection from this neurotoxin include double vision, blurred vision, drooping eyelids, slurred speech, difficulty swallowing, dry mouth, and muscle weakness. Botulism prevents muscle contraction by blocking

1344-462: A type of monkey kidney tissue culture ( vero cell line ), which is chemically inactivated with formalin . After two doses of IPV (given by injection ), 90 percent or more of individuals develop protective antibody to all three serotypes of poliovirus, and at least 99 percent are immune to poliovirus following three doses. Subsequently, Albert Sabin developed a polio vaccine that can be administered orally (oral polio vaccine - OPV), comprising

1428-507: Is a neurological condition characterized by weakness or paralysis and reduced muscle tone without other obvious cause (e.g., trauma ). This abnormal condition may be caused by disease or by trauma affecting the nerves associated with the involved muscles. For example, if the somatic nerves to a skeletal muscle are severed, then the muscle will exhibit flaccid paralysis. When muscles enter this state, they become limp and cannot contract . This condition can become fatal if it affects

1512-481: Is also associated with a number of other pathogenic agents including enteroviruses other than polio, echoviruses , West Nile virus , and adenoviruses , among others. The Clostridium botulinum bacteria are the cause of botulism . Vegetative cells of C. botulinum may be ingested. Introduction of the bacteria may also occur via endospores in a wound. When the bacteria are in vivo , they induce flaccid paralysis. This happens because C. botulinum produces

1596-455: Is called respiratory or bulbospinal polio. Here, the virus affects the upper part of the cervical spinal cord ( cervical vertebrae C3 through C5), and paralysis of the diaphragm occurs. The critical nerves affected are the phrenic nerve (which drives the diaphragm to inflate the lungs ) and those that drive the muscles needed for swallowing. By destroying these nerves, this form of polio affects breathing, making it difficult or impossible for

1680-404: Is caused by infection with a member of the genus Enterovirus known as poliovirus (PV). This group of RNA viruses colonize the gastrointestinal tract  – specifically the oropharynx and the intestine . Its structure is quite simple, composed of a single (+) sense RNA genome enclosed in a protein shell called a capsid . In addition to protecting the virus' genetic material,

1764-807: Is conducted to increase case yield of poliomyelitis. This includes collection of two stool samples within fourteen days of onset of paralysis and identification of virus, and control of the outbreak and strengthening immunization in that area. Historical records from the 1950s, modern CDC reports, and recent analysis of patterns in India suggest that flaccid paralysis may be caused in some cases by oral polio vaccinations. Venomous snakes that contain neurotoxic venom such as kraits , mambas , and cobras can also cause complete flaccid paralysis. Some chemical warfare nerve agents such as VX can also cause complete flaccid paralysis. In some situations, prominently in those of oriental descent hyperthyroidism can affect

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1848-415: Is highly infectious, and is spread from person to person either through fecal–oral transmission (e.g. poor hygiene, or by ingestion of food or water contaminated by human feces), or via the oral–oral route. Those who are infected may spread the disease for up to six weeks even if no symptoms are present. The disease may be diagnosed by finding the virus in the feces or detecting antibodies against it in

1932-413: Is less effective at preventing spread of wild poliovirus by the fecal–oral route. Because the oral polio vaccine is inexpensive, easy to administer, and produces excellent immunity in the intestine (which helps prevent infection with wild virus in areas where it is endemic ), it has been the vaccine of choice for controlling poliomyelitis in many countries. On very rare occasions, the attenuated virus in

2016-416: Is most infectious between 7 and 10 days before and after the appearance of symptoms, but transmission is possible as long as the virus remains in the saliva or feces. Virus particles can be excreted in the feces for up to six weeks. Factors that increase the risk of polio infection include pregnancy , the very old and the very young, immune deficiency , and malnutrition . Although the virus can cross

2100-420: Is possible up to 18 months after infection. One mechanism involved in recovery is nerve terminal sprouting, in which remaining brainstem and spinal cord motor neurons develop new branches, or axonal sprouts. These sprouts can reinnervate orphaned muscle fibers that have been denervated by acute polio infection, restoring the fibers' capacity to contract and improving strength. Terminal sprouting may generate

2184-430: Is that one leg is shorter than the other and the person limps and leans to one side, in turn leading to deformities of the spine (such as scoliosis ). Osteoporosis and increased likelihood of bone fractures may occur. An intervention to prevent or lessen length disparity can be to perform an epiphysiodesis on the distal femoral and proximal tibial/fibular condyles, so that limb's growth is artificially stunted, and by

2268-442: Is used to identify the disease caused by any of the three serotypes of poliovirus. Two basic patterns of polio infection are described: a minor illness that does not involve the central nervous system (CNS), sometimes called abortive poliomyelitis, and a major illness involving the CNS, which may be paralytic or nonparalytic. Adults are more likely to develop symptoms, including severe symptoms, than children. In most people with

2352-443: Is usually complete by the time the fever breaks. The likelihood of developing paralytic polio increases with age, as does the extent of paralysis. In children, nonparalytic meningitis is the most likely consequence of CNS involvement, and paralysis occurs in only one in 1000 cases. In adults, paralysis occurs in one in 75 cases. In children under five years of age, paralysis of one leg is most common; in adults, extensive paralysis of

2436-463: Is usually made based on the recovery of poliovirus from a stool sample or a swab of the pharynx . Rarely, it may be possible to identify poliovirus in the blood or in the cerebrospinal fluid . Poliovirus samples are further analysed using reverse transcription polymerase chain reaction (RT-PCR) or genomic sequencing to determine the serotype (i.e., 1, 2, or 3), and whether the virus is a wild or vaccine-derived strain. In 1950, William Hammon at

2520-587: The Radcliffe Infirmary where a short film was made of the device. This film was subsequently shown to William Morris (Lord Nuffield) by Robert Macintosh , the department's Professor. Nuffield was the manufacturer of the Morris motor car as well as a philanthropist. Nuffield was taken by the design, and in November of that year he offered to turn over part of his car factory for the manufacture of

2604-716: The United States , and in the 20th century, it became one of the most worrying childhood diseases . Following the introduction of polio vaccines in the 1950s, polio incidence declined rapidly. As of October 2023 , only Pakistan and Afghanistan remain endemic for wild poliovirus (WPV). Once infected, there is no specific treatment. The disease can be prevented by the polio vaccine , with multiple doses required for lifelong protection. There are two broad types of polio vaccine; an injected polio vaccine (IPV) using inactivated poliovirus and an oral polio vaccine (OPV) containing attenuated (weakened) live virus. Through

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2688-464: The University of Pittsburgh purified the gamma globulin component of the blood plasma of polio survivors. Hammon proposed the gamma globulin, which contained antibodies to poliovirus, could be used to halt poliovirus infection, prevent disease, and reduce the severity of disease in other patients who had contracted polio. The results of a large clinical trial were promising; the gamma globulin

2772-422: The chest and abdomen also affecting all four limbs – quadriplegia  – is more likely. Paralysis rates also vary depending on the serotype of the infecting poliovirus; the highest rates of paralysis (one in 200) are associated with poliovirus type 1, the lowest rates (one in 2,000) are associated with type 2. Spinal polio, the most common form of paralytic poliomyelitis, results from viral invasion of

2856-421: The cranial nerves , producing symptoms of encephalitis , and causes difficulty breathing , speaking and swallowing. Critical nerves affected are the glossopharyngeal nerve (which partially controls swallowing and functions in the throat, tongue movement, and taste), the vagus nerve (which sends signals to the heart, intestines, and lungs), and the accessory nerve (which controls upper neck movement). Due to

2940-411: The maternal-fetal barrier during pregnancy, the fetus does not appear to be affected by either maternal infection or polio vaccination. Maternal antibodies also cross the placenta , providing passive immunity that protects the infant from polio infection during the first few months of life. Poliovirus enters the body through the mouth, infecting the first cells with which it comes in contact –

3024-422: The pharynx and intestinal mucosa . It gains entry by binding to an immunoglobulin-like receptor, known as the poliovirus receptor or CD155 , on the cell membrane. The virus then hijacks the host cell's own machinery, and begins to replicate . Poliovirus divides within gastrointestinal cells for about a week, from where it spreads to the tonsils (specifically the follicular dendritic cells residing within

3108-432: The respiratory muscles , posing the threat of suffocation . It also occurs in the spinal shock stage in complete transection of the spinal cord occurring in injuries such as gunshot wounds. The term acute flaccid paralysis (AFP) is often used to describe an instance with a sudden onset, as might be found with polio. AFP is the most common sign of acute polio , and used for surveillance during polio outbreaks. AFP

3192-680: The tonsils and gastrointestinal tract and able to block virus replication ; IgG and IgM antibodies against PV can prevent the spread of the virus to motor neurons of the central nervous system . Infection or vaccination with one serotype of poliovirus does not provide immunity against the other serotypes, and full immunity requires exposure to each serotype. A rare condition with a similar presentation, nonpoliovirus poliomyelitis, may result from infections with enteroviruses other than poliovirus. The oral polio vaccine, which has been in use since 1961, contains weakened viruses that can replicate. On rare occasions, these may be transmitted from

3276-594: The Both respirators and to provide the respirators free of charge to any hospital in the Commonwealth that requested one. In spite of some initial opposition – Nuffield was criticized in the British Medical Journal by Frederick Menzies for using a design before the iron lung had been perfected, and for supplying it to hospitals which may lack the knowledge as to how to employ it – over 1,700 Both–Nuffield respirators were distributed to hospitals. By

3360-399: The CNS are poorly understood, but it appears to be primarily a chance event – largely independent of the age, gender, or socioeconomic position of the individual. In around one percent of infections, poliovirus spreads along certain nerve fiber pathways, preferentially replicating in and destroying motor neurons within the spinal cord , brain stem , or motor cortex . This leads to

3444-562: The Sabin OPV can revert into a form that can paralyze. In 2017, cases caused by vaccine-derived poliovirus (cVDPV) outnumbered wild poliovirus cases for the first time, due to wild polio cases hitting record lows. Most industrialized countries have switched to inactivated polio vaccine, which cannot revert, either as the sole vaccine against poliomyelitis or in combination with oral polio vaccine. An improved oral vaccine (Novel oral polio vaccine type 2 - nOPV2) began development in 2011 and

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3528-404: The acute infection, notably new muscle weakness and extreme fatigue. This condition is known as post-polio syndrome (PPS) or post-polio sequelae. The symptoms of PPS are thought to involve a failure of the oversized motor units created during the recovery phase of the paralytic disease. Contributing factors that increase the risk of PPS include aging with loss of neuron units, the presence of

3612-430: The blood and lymphatics for long periods of time, sometimes as long as 17 weeks. In a small percentage of cases, it can spread and replicate in other sites, such as brown fat , the reticuloendothelial tissues, and muscle. This sustained replication causes a major viremia, and leads to the development of minor influenza-like symptoms. Rarely, this may progress and the virus may invade the central nervous system, provoking

3696-575: The blood. Poliomyelitis has existed for thousands of years, with depictions of the disease in ancient art. The disease was first recognized as a distinct condition by the English physician Michael Underwood in 1789, and the virus that causes it was first identified in 1909 by the Austrian immunologist Karl Landsteiner . Major outbreaks started to occur in the late 19th century in Europe and

3780-446: The body can compensate for residual paralysis in other ways. Weaker muscles can be used at a higher than usual intensity relative to the muscle's maximal capacity , little-used muscles can be developed, and ligaments can enable stability and mobility. Residual complications of paralytic polio often occur following the initial recovery process. Muscle paresis and paralysis can sometimes result in skeletal deformities, tightening of

3864-427: The capsid proteins enable poliovirus to infect certain types of cells. Three serotypes of poliovirus have been identified – wild poliovirus type 1 (WPV1), type 2 (WPV2), and type 3 (WPV3) – each with a slightly different capsid protein. All three are extremely virulent and produce the same disease symptoms. WPV1 is the most commonly encountered form, and the one most closely associated with paralysis. WPV2

3948-693: The color and appearance of the gray matter in the spinal column , causing it to appear reddish and swollen. Other destructive changes associated with paralytic disease occur in the forebrain region, specifically the hypothalamus and thalamus . Early symptoms of paralytic polio include high fever, headache, stiffness in the back and neck, asymmetrical weakness of various muscles, sensitivity to touch, difficulty swallowing , muscle pain , loss of superficial and deep reflexes , paresthesia (pins and needles), irritability, constipation, or difficulty urinating. Paralysis generally develops one to ten days after early symptoms begin, progresses for two to three days, and

4032-491: The development of paralytic poliomyelitis, the various forms of which (spinal, bulbar, and bulbospinal) vary only with the amount of neuronal damage and inflammation that occurs, and the region of the CNS affected. The destruction of neuronal cells produces lesions within the spinal ganglia ; these may also occur in the reticular formation , vestibular nuclei , cerebellar vermis , and deep cerebellar nuclei . Inflammation associated with nerve cell destruction often alters

4116-528: The early 1950s there were over 700 Both–Nuffield iron lungs in the United Kingdom, compared with only 50 Drinker's models. Poliomyelitis Poliomyelitis ( / ˌ p oʊ l i oʊ ˌ m aɪ ə ˈ l aɪ t ɪ s / POH -lee-oh- MY -ə- LY -tiss ), commonly shortened to polio , is an infectious disease caused by the poliovirus . Approximately 75% of cases are asymptomatic; mild symptoms which can occur include sore throat and fever; in

4200-622: The effect on swallowing, secretions of mucus may build up in the airway, causing suffocation. Other signs and symptoms include facial weakness (caused by destruction of the trigeminal nerve and facial nerve , which innervate the cheeks, tear ducts , gums, and muscles of the face, among other structures), double vision , difficulty in chewing, and abnormal respiratory rate , depth, and rhythm (which may lead to respiratory arrest ). Pulmonary edema and shock are also possible and may be fatal. Approximately 19 percent of all paralytic polio cases have both bulbar and spinal symptoms; this subtype

4284-536: The grey matter of the spinal cord , and the suffix -itis , which denotes inflammation , i.e., inflammation of the spinal cord's grey matter. The word was first used in 1874 and is attributed to the German physician Adolf Kussmaul . The first recorded use of the abbreviated version polio was in the Indianapolis Star in 1911. Poliomyelitis does not affect any species other than humans. The disease

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4368-400: The joints, and movement disability. Once the muscles in the limb become flaccid, they may interfere with the function of other muscles. A typical manifestation of this problem is equinus foot (similar to club foot ). This deformity develops when the muscles that pull the toes downward are working, but those that pull it upward are not, and the foot naturally tends to drop toward the ground. If

4452-464: The legs, due to pooling of blood in paralyzed lower limbs. Complications from prolonged immobility involving the lungs , kidneys and heart include pulmonary edema , aspiration pneumonia , urinary tract infections , kidney stones , paralytic ileus , myocarditis and cor pulmonale . Between 25 percent and 50 percent of individuals who have recovered from paralytic polio in childhood can develop additional symptoms decades after recovering from

4536-409: The limb joins the body) than distally (the fingertips and toes ). Making up about two percent of cases of paralytic polio, bulbar polio occurs when poliovirus invades and destroys nerves within the bulbar region of the brain stem . The bulbar region is a white matter pathway that connects the cerebral cortex to the brain stem. The destruction of these nerves weakens the muscles supplied by

4620-482: The motor neurons of the anterior horn cells , or the ventral (front) grey matter section in the spinal column , which are responsible for movement of the muscles, including those of the trunk , limbs , and the intercostal muscles . Virus invasion causes inflammation of the nerve cells, leading to damage or destruction of motor neuron ganglia . When spinal neurons die, Wallerian degeneration takes place, leading to weakness of those muscles formerly innervated by

4704-442: The muscles become weak, floppy and poorly controlled, and, finally, completely paralyzed; this condition is known as acute flaccid paralysis . The weakness most often involves the legs, but may less commonly involve the muscles of the head, neck, and diaphragm . Depending on the site of paralysis, paralytic poliomyelitis is classified as spinal, bulbar , or bulbospinal. In those who develop paralysis, between 2 and 10 percent die as

4788-417: The natural or "wild" poliovirus (WPV). Poliomyelitis is highly contagious. The disease is transmitted primarily via the fecal–oral route , by ingesting contaminated food or water. It is occasionally transmitted via the oral–oral route. It is seasonal in temperate climates , with peak transmission occurring in summer and autumn. These seasonal differences are far less pronounced in tropical areas. Polio

4872-478: The now-dead neurons. With the destruction of nerve cells, the muscles no longer receive signals from the brain or spinal cord; without nerve stimulation, the muscles atrophy , becoming weak, floppy and poorly controlled, and finally completely paralyzed. Maximum paralysis progresses rapidly (two to four days), and usually involves fever and muscle pain. Deep tendon reflexes are also affected, and are typically absent or diminished; sensation (the ability to feel) in

4956-512: The paralysis affects the breathing muscles. Encephalitis , an infection of the brain tissue itself, can occur in rare cases, and is usually restricted to infants. It is characterized by confusion, changes in mental status, headaches, fever, and, less commonly, seizures and spastic paralysis . The term poliomyelitis derives from the Ancient Greek poliós ( πολιός ), meaning "grey", myelós ( µυελός "marrow"), referring to

5040-550: The paralysis of muscles used for breathing. The case fatality rate (CFR) varies by age: 2 to 5 percent of children and up to 15 to 30 percent of adults die. Bulbar polio often causes death if respiratory support is not provided; with support, its CFR ranges from 25 to 75 percent, depending on the age of the patient. When intermittent positive pressure ventilation is available, the fatalities can be reduced to 15 percent. Many cases of poliomyelitis result in only temporary paralysis. Generally in these cases, nerve impulses return to

5124-436: The paralyzed limbs, however, is not affected. The extent of spinal paralysis depends on the region of the cord affected, which may be cervical , thoracic , or lumbar . The virus may affect muscles on both sides of the body, but more often the paralysis is asymmetrical . Any limb or combination of limbs may be affected – one leg, one arm, or both legs and both arms. Paralysis is often more severe proximally (where

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5208-407: The paralyzed muscle within a month, and recovery is complete in six to eight months. The neurophysiological processes involved in recovery following acute paralytic poliomyelitis are quite effective; muscles are able to retain normal strength even if half the original motor neurons have been lost. Paralysis remaining after one year is likely to be permanent, although some recovery of muscle strength

5292-479: The patient to breathe without the support of a ventilator . It can lead to paralysis of the arms and legs and may also affect swallowing and heart functions. Paralytic poliomyelitis may be clinically suspected in individuals experiencing acute onset of flaccid paralysis in one or more limbs with decreased or absent tendon reflexes in the affected limbs that cannot be attributed to another apparent cause, and without sensory or cognitive loss. A laboratory diagnosis

5376-469: The population declined providing circumstances where epidemics of polio became frequent. It is estimated that epidemic polio killed or paralysed over half a million people every year. Following the widespread use of poliovirus vaccine in the mid-1950s, new cases of poliomyelitis declined dramatically in many industrialized countries. Efforts to completely eradicate the disease started in 1988 and are ongoing. Flaccid paralysis Flaccid paralysis

5460-491: The problem is left untreated, the Achilles tendons at the back of the foot retract and the foot cannot take on a normal position. People with polio that develop equinus foot cannot walk properly because they cannot put their heels on the ground. A similar situation can develop if the arms become paralyzed. In some cases the growth of an affected leg is slowed by polio, while the other leg continues to grow normally. The result

5544-487: The region – notably the Macushi – crush and cook the roots and stems of these and certain other plants and then mix the resulting decoction with various other plant poisons and animal venoms to create a syrupy liquid in which to dip their arrow heads and the tips of their blowgun darts. Curare has also been used medicinally by South Americans to treat madness, dropsy, edema, fever, kidney stones, and bruises. Curare acts as

5628-443: The release of acetylcholine, thereby halting postsynaptic activity of the neuromuscular junction. If its effects reach the respiratory muscles, then it can lead to respiratory failure, leading to death. Curare is a plant poison derived from – among other species – Chondrodendron tomentosum and various species belonging to the genus Strychnos , which are native to the rainforests of South America. Certain peoples indigenous to

5712-490: The remaining quarter are left with severe disability. The degree of both acute paralysis and residual paralysis is likely to be proportional to the degree of viremia , and inversely proportional to the degree of immunity . Spinal polio is rarely fatal. Without respiratory support, consequences of poliomyelitis with respiratory involvement include suffocation or pneumonia from aspiration of secretions . Overall, 5 to 10 percent of patients with paralytic polio die due to

5796-426: The swing phase is initiated. With the help of an orthotic treatment with a stance phase control knee joint, a natural gait pattern can be achieved despite mechanical protection against unwanted knee flexion. In these cases, locked knee joints are often used, which have a good safety function, but do not allow knee flexion when walking during swing phase. With such joints, the knee joint remains mechanically blocked during

5880-430: The swing phase. Patients with locked knee joints must swing the leg forward with the knee extended even during the swing phase. This only works if the patient develops compensatory mechanisms, e.g. by raising the body's center of gravity in the swing phase (Duchenne limping) or by swinging the orthotic leg to the side (circumduction). Major polio epidemics were unknown before the 20th century; up until that time, polio

5964-410: The symptoms can be expected to persist for two to ten days, followed by complete recovery. In cases of spinal polio, if the affected nerve cells are completely destroyed, paralysis will be permanent; cells that are not destroyed, but lose function temporarily, may recover within four to six weeks after onset. Half the patients with spinal polio recover fully; one-quarter recover with mild disability, and

6048-411: The time of epiphyseal (growth) plate closure, the legs are more equal in length. Alternatively, a person can be fitted with custom-made footwear which corrects the difference in leg lengths. Other surgery to re-balance muscular agonist/antagonist imbalances may also be helpful. Extended use of braces or wheelchairs may cause compression neuropathy , as well as a loss of proper function of the veins in

6132-421: The tonsilar germinal centers ), the intestinal lymphoid tissue including the M cells of Peyer's patches , and the deep cervical and mesenteric lymph nodes , where it multiplies abundantly. The virus is subsequently absorbed into the bloodstream. Known as viremia , the presence of a virus in the bloodstream enables it to be widely distributed throughout the body. Poliovirus can survive and multiply within

6216-461: The use of both types of vaccine, incidence of wild polio has decreased from an estimated 350,000 cases in 1988 to 30 confirmed cases in 2022, confined to just three countries. In rare cases, the traditional OPV was able to revert to a virulent form. An improved oral vaccine with greater genetic stability (nOPV2) was developed and granted full licensure in December 2023. The term "poliomyelitis"

6300-431: The vaccinated person to other people; in communities with good vaccine coverage , transmission is limited, and the virus dies out. In communities with low vaccine coverage, this weakened virus may continue to circulate and, over time may mutate and revert to a virulent form. Polio arising from this cause is referred to as circulating vaccine-derived poliovirus (cVDPV) or variant poliovirus in order to distinguish it from

6384-519: The victim at risk for suffocation. Flaccid paralysis can be associated with a lower motor neuron lesion . This is in contrast to an upper motor neuron lesion , which often presents with spasticity , although early on this may present with flaccid paralysis. Included in AFP's list are poliomyelitis (polio), transverse myelitis, Guillain–Barré syndrome , enteroviral encephalopathy, traumatic neuritis, Reye's syndrome , etc. An AFP surveillance programme

6468-476: The world to combat polio: an inactivated poliovirus given by injection, and a weakened poliovirus given by mouth. Both types induce immunity to polio and are effective in protecting individuals from disease. The inactivated polio vaccine (IPV) was developed in 1952 by Jonas Salk at the University of Pittsburgh, and announced to the world on 12 April 1955. The Salk vaccine is based on poliovirus grown in

6552-413: Was an endemic disease worldwide. Mothers who had survived polio infection passed on temporary immunity to their babies in the womb and through breast milk. As a result, an infant who encountered a polio infection generally suffered only mild symptoms and acquired a long-term immunity to the disease. With improvements in sanitation and hygiene during the 19th century, the general level of herd immunity in

6636-493: Was certified as eradicated in 2015 and WPV3 certified as eradicated in 2019. The incubation period (from exposure to the first signs and symptoms) ranges from three to six days for nonparalytic polio. If the disease progresses to cause paralysis, this occurs within 7 to 21 days. Individuals who are exposed to the virus, either through infection or by immunization via polio vaccine , develop immunity . In immune individuals, IgA antibodies against poliovirus are present in

6720-518: Was granted emergency licencing in 2021, and subsequently full licensure in December 2023. This has greater genetic stability than the traditional oral vaccine and is less likely to revert to a virulent form. There is no cure for polio, but there are treatments. The focus of modern treatment has been on providing relief of symptoms, speeding recovery and preventing complications. Supportive measures include antibiotics to prevent infections in weakened muscles, analgesics for pain, moderate exercise and

6804-529: Was hampered by a number of factors, most notably cost, the heavy weight of the device, and the need to ship the device to the United States for servicing, and thus there were few of the devices in the country. Adelaide inventor Edward Both was approached in the hope that he could provide an alternative to meet the demand brought on by the epidemic. Both ran Both Equipment Limited with his brother Donald, and had previously developed medical apparatus. It took

6888-650: Was selected, in competition with the live attenuated vaccines of Koprowski and other researchers, by the US National Institutes of Health. Licensed in 1962, it rapidly became the only oral polio vaccine used worldwide. OPV efficiently blocks person-to-person transmission of wild poliovirus by oral–oral and fecal–oral routes, thereby protecting both individual vaccine recipients and the wider community. The live attenuated virus may be transmitted from vaccinees to their unvaccinated contacts, resulting in wider community immunity. IPV confers good immunity but

6972-413: Was shown to be about 80 percent effective in preventing the development of paralytic poliomyelitis. It was also shown to reduce the severity of the disease in patients who developed polio. Due to the limited supply of blood plasma gamma globulin was later deemed impractical for widespread use and the medical community focused on the development of a polio vaccine. Two types of vaccine are used throughout

7056-587: Was simple enough that hospitals could build their own in their workshops, and it soon proved to be a success. The portability also opened up other possibilities, and as a result people who needed extended assistance from the device were able to use one in their private residences: indeed, in 2003 there were still five privately owned Both respirators being used in residences within Victoria. In 1938, Edward Both traveled to England to sell an electrocardiograph which he had invented. While there, he heard over BBC Radio

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