[go: up one dir, main page]
Wikipedia

Polio

"Poliomyelitis" redirects here. For the virus, see Poliovirus. For other uses, see Polio (disambiguation).

Poliomyelitis (/ˌpoʊlioʊˌmaɪəˈlaɪtɪs/ POH-lee-oh-MY-ə-LY-tiss), commonly shortened to polio, is an infectious disease caused by the poliovirus.[1] Approximately 75% of cases are asymptomatic;[5] mild symptoms which can occur include sore throat and fever; in a proportion of cases more severe symptoms develop such as headache, neck stiffness, and paresthesia.[1][3] These symptoms usually pass within one or two weeks. A less common symptom is permanent paralysis, and possible death in extreme cases.[1] 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.[2]

Polio
Other namesPoliomyelitis, infantile paralysis, Heine–Medin disease
Polio survivor
A man with a wasted right leg due to poliomyelitis
Pronunciation
SpecialtyNeurology, infectious disease
SymptomsFever, sore throat[1]
ComplicationsMuscle weakness resulting in paralysis;[1] Post-polio syndrome[2]
TypesWild PV types 1,2 & 3; vaccine-derived PV[1]
CausesPoliovirus spread by fecal–oral route[1]
Risk factorsPoor hygiene
Diagnostic methodFinding the virus in the feces or antibodies in the blood[1]
PreventionPolio vaccine[3]
TreatmentNo treatment other than supportive care[3]
Frequency30 (wild) + 856 (vaccine-derived) in 2022[4]

Polio occurs naturally only in humans.[1] It is highly infectious, and is spread from person to person either through fecal–oral transmission[1][6] (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 the blood.[1]

Poliomyelitis has existed for thousands of years, with depictions of the disease in ancient art.[1] The disease was first recognized as a distinct condition by the English physician Michael Underwood in 1789,[1][7] and the virus that causes it was first identified in 1909 by the Austrian immunologist Karl Landsteiner.[8][9] Major outbreaks started to occur in the late 19th century in Europe and the United States,[1] and in the 20th century, it became one of the most worrying childhood diseases.[10] Following the introduction of polio vaccines in the 1950s, polio incidence declined rapidly.[1] As of October 2023, only Pakistan and Afghanistan remain endemic for wild poliovirus (WPV).[11]

Once infected, there is no specific treatment.[3] The disease can be prevented by the polio vaccine, with multiple doses required for lifelong protection.[3] 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.[1] Through the use of both types of vaccine, incidence of wild polio has decreased from an estimated 350,000 cases in 1988[3] to 30 confirmed cases in 2022, confined to just three countries.[12] 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.[13][14]

Signs and symptoms

Outcomes of poliovirus infection in children
Outcome Proportion of cases[1]
No symptoms 72%
Minor illness 24%
Nonparalytic aseptic
meningitis 		1–5%
Paralytic poliomyelitis 0.1–0.5%
— Spinal polio 79% of paralytic cases
— Bulbospinal polio 19% of paralytic cases
— Bulbar polio 2% of paralytic cases

The term "poliomyelitis" 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.[15] Adults are more likely to develop symptoms, including severe symptoms, than children.[1]

In most people with 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.[3][5] These symptoms are temporary and full recovery occurs within one or two weeks.[1][3]

In about 1 percent of infections the virus can migrate from the gastrointestinal tract into the central nervous system (CNS).[1] 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.[16][17][18] About one to five in 1,000 cases progress to paralytic disease, in which the muscles become weak, floppy and poorly controlled, and, finally, completely paralyzed; this condition is known as acute flaccid paralysis.[19] The weakness most often involves the legs, but may less commonly involve the muscles of the head, neck, and diaphragm.[1] 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 the paralysis affects the breathing muscles.[3]

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.[20]

Etymology

The term poliomyelitis derives from the Ancient Greek poliós (πολιός), meaning "grey", myelós (µυελός "marrow"), referring to the grey matter of the spinal cord, and the suffix -itis, which denotes inflammation,[16] 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.[21] The first recorded use of the abbreviated version polio was in the Indianapolis Star in 1911.[22]

Cause

Main article: Poliovirus
 
A transmission electron microscope micrograph of poliovirus

Poliomyelitis does not affect any species other than humans.[23] The disease is caused by infection with a member of the genus Enterovirus known as poliovirus (PV). This group of RNA viruses colonize the gastrointestinal tract[24] – 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.[23] In addition to protecting the virus' genetic material, 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.[25] All three are extremely virulent and produce the same disease symptoms.[23] WPV1 is the most commonly encountered form, and the one most closely associated with paralysis.[26] WPV2 was certified as eradicated in 2015 and WPV3 certified as eradicated in 2019.[27]

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.[1]

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 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.[28] Infection or vaccination with one serotype of poliovirus does not provide immunity against the other serotypes, and full immunity requires exposure to each serotype.[28]

A rare condition with a similar presentation, nonpoliovirus poliomyelitis, may result from infections with enteroviruses other than poliovirus.[29]

The oral polio vaccine, which has been in use since 1961,[30] contains weakened viruses that can replicate. On rare occasions, these may be transmitted from 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.[31] Polio arising from this cause is referred to as circulating vaccine-derived poliovirus (cVDPV) or variant poliovirus in order to distinguish it from the natural or "wild" poliovirus (WPV).[32]

Transmission

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.[1] It is seasonal in temperate climates, with peak transmission occurring in summer and autumn. These seasonal differences are far less pronounced in tropical areas.[28] Polio 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.[5]

Factors that increase the risk of polio infection include pregnancy,[33] the very old and the very young, immune deficiency,[34] and malnutrition.[35] Although the virus can cross the maternal-fetal barrier during pregnancy, the fetus does not appear to be affected by either maternal infection or polio vaccination.[36] Maternal antibodies also cross the placenta, providing passive immunity that protects the infant from polio infection during the first few months of life.[37]

Pathophysiology

 
A photomicrograph of the lumbar spinal cord depicting an infarct due to Polio Type III surrounding the anterior spinal artery

Poliovirus enters the body through the mouth, infecting the first cells with which it comes in contact – 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.[38] 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 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.[39]

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 the blood and lymphatics for long periods of time, sometimes as long as 17 weeks.[40] In a small percentage of cases, it can spread and replicate in other sites, such as brown fat, the reticuloendothelial tissues, and muscle.[41] 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 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.[16] Penetration of the CNS provides no known benefit to the virus, and is quite possibly an incidental deviation of a normal gastrointestinal infection.[42] The mechanisms by which poliovirus spreads to 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.[42]

Paralytic polio

 
Denervation of skeletal muscle tissue secondary to poliovirus infection can lead to paralysis.

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 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.[43]

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.[42] Inflammation associated with nerve cell destruction often alters the color and appearance of the gray matter in the spinal column, causing it to appear reddish and swollen.[16] Other destructive changes associated with paralytic disease occur in the forebrain region, specifically the hypothalamus and thalamus.[42]

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 is usually complete by the time the fever breaks.[44]

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.[45] In children under five years of age, paralysis of one leg is most common; in adults, extensive paralysis of the chest and abdomen also affecting all four limbs – quadriplegia – is more likely.[46] 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.[47]

Spinal polio

 
The location of motor neurons in the anterior horn cells of the spinal column

Spinal polio, the most common form of paralytic poliomyelitis, results from viral invasion of 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.[19] 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 the now-dead neurons.[48] 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.[19] 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 the paralyzed limbs, however, is not affected.[49]

The extent of spinal paralysis depends on the region of the cord affected, which may be cervical, thoracic, or lumbar.[50] The virus may affect muscles on both sides of the body, but more often the paralysis is asymmetrical.[39] 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 the limb joins the body) than distally (the fingertips and toes).[39]

Bulbar polio

 
The location and anatomy of the bulbar region (in orange)

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.[1] 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 the cranial nerves, producing symptoms of encephalitis, and causes difficulty breathing, speaking and swallowing.[18] 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 the effect on swallowing, secretions of mucus may build up in the airway, causing suffocation.[44] 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.[50]

Bulbospinal polio

Approximately 19 percent of all paralytic polio cases have both bulbar and spinal symptoms; this subtype is called respiratory or bulbospinal polio.[1] 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 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.[51]

Diagnosis

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.[52]

A laboratory diagnosis 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.[1]

Prevention

Passive immunization

In 1950, William Hammon at the University of Pittsburgh purified the gamma globulin component of the blood plasma of polio survivors.[53] 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 was shown to be about 80 percent effective in preventing the development of paralytic poliomyelitis.[54] It was also shown to reduce the severity of the disease in patients who developed polio.[53] 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.[55]

Vaccine

Main article: Polio vaccine
 
A child receiving an oral polio vaccine

Two types of vaccine are used throughout 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.[56]

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.[57] The Salk vaccine is based on poliovirus grown in a type of monkey kidney tissue culture (vero cell line), which is chemically inactivated with formalin.[28] 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.[1]

Subsequently, Albert Sabin developed a polio vaccine that can be administered orally (oral polio vaccine - OPV), comprising a live, attenuated virus. It was produced by the repeated passage of the virus through nonhuman cells at subphysiological temperatures.[58] 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.[59] 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.[1] Human trials of Sabin's vaccine began in 1957,[60] and in 1958, it was selected, in competition with the live attenuated vaccines of Koprowski and other researchers, by the US National Institutes of Health.[61] Licensed in 1962,[60] it rapidly became the only oral polio vaccine used worldwide.[61]

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.[62] IPV confers good immunity but is less effective at preventing spread of wild poliovirus by the fecal–oral route.[63]

 
Wild polio vs cVDPV cases (2000–2019)

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.[64] On very rare occasions, the attenuated virus in the Sabin OPV can revert into a form that can paralyze.[65] 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.[66] 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.[67]

An improved oral vaccine (Novel oral polio vaccine type 2 - nOPV2) began development in 2011 and was granted emergency licencing in 2021, and subsequently full licensure in December 2023.[14] This has greater genetic stability than the traditional oral vaccine and is less likely to revert to a virulent form.[14]

Treatment

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 a nutritious diet.[68] Treatment of polio often requires long-term rehabilitation, including occupational therapy, physical therapy, braces, corrective shoes and, in some cases, orthopedic surgery.[50]

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 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[69] and due to the eradication of polio in most of the world.[70]

Other historical treatments for polio include hydrotherapy, electrotherapy, massage and passive motion exercises, and surgical treatments, such as tendon lengthening and nerve grafting.[19]

Prognosis

 
A girl with genu recurvatum of her right leg due to polio

Patients with abortive polio infections recover completely. In those who develop only aseptic meningitis, the symptoms can be expected to persist for two to ten days, followed by complete recovery.[71] 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.[71] Half the patients with spinal polio recover fully; one-quarter recover with mild disability, and the remaining quarter are left with severe disability.[72] 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.[42] Spinal polio is rarely fatal.[44]

Without respiratory support, consequences of poliomyelitis with respiratory involvement include suffocation or pneumonia from aspiration of secretions.[73] Overall, 5 to 10 percent of patients with paralytic polio die due to 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.[1] Bulbar polio often causes death if respiratory support is not provided;[51] with support, its CFR ranges from 25 to 75 percent, depending on the age of the patient.[1][74] When intermittent positive pressure ventilation is available, the fatalities can be reduced to 15 percent.[75]

Recovery

Many cases of poliomyelitis result in only temporary paralysis.[19] Generally in these cases, nerve impulses return to the paralyzed muscle within a month, and recovery is complete in six to eight months.[71] 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.[76] Paralysis remaining after one year is likely to be permanent, although some recovery of muscle strength is possible up to 18 months after infection.[71]

One mechanism involved in recovery is nerve terminal sprouting, in which remaining brainstem and spinal cord motor neurons develop new branches, or axonal sprouts.[77] These sprouts can reinnervate orphaned muscle fibers that have been denervated by acute polio infection,[78] restoring the fibers' capacity to contract and improving strength.[79] Terminal sprouting may generate a few significantly enlarged motor neurons doing work previously performed by as many as four or five units:[45] 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.[78][80]

In addition to these physiological processes, 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.[80]

Complications

Residual complications of paralytic polio often occur following the initial recovery process.[18] Muscle paresis and paralysis can sometimes result in skeletal deformities, tightening of 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 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.[81]

In some cases the growth of an affected leg is slowed by polio, while the other leg continues to grow normally. The result 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).[81] 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 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 the legs, due to pooling of blood in paralyzed lower limbs.[51][82] 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.[51][82]

Post-polio syndrome

Main article: Post-polio syndrome

Between 25 percent and 50 percent of individuals who have recovered from paralytic polio in childhood can develop additional symptoms decades after recovering from the acute infection,[83] notably new muscle weakness and extreme fatigue. This condition is known as post-polio syndrome (PPS) or post-polio sequelae.[79] The symptoms of PPS are thought to involve a failure of the oversized motor units created during the recovery phase of the paralytic disease.[84][85] Contributing factors that increase the risk of PPS include aging with loss of neuron units, the presence of 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.[79] Post-polio syndrome is not an infectious process, and persons experiencing the syndrome do not shed poliovirus.[1]

Orthotics

 
Orthosis with stance phase control knee joint

Paralysis, length differences and deformations of the lower extremities can lead to a hindrance when walking with compensation mechanisms that lead to 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 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 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).[86][87][88]

Epidemiology

Major polio epidemics were unknown before the 20th century; up until that time, polio was an endemic disease worldwide.[89] Mothers who had survived polio infection passed on temporary immunity to their babies in the womb and through breast milk.[90] As a result, an infant who encountered a polio infection generally suffered only mild symptoms and acquired a long-term immunity to the disease.[91] With improvements in sanitation and hygiene during the 19th century, the general level of herd immunity in the population declined providing circumstances where epidemics of polio became frequent.[91] It is estimated that epidemic polio killed or paralysed over half a million people every year.[92]

Following the widespread use of poliovirus vaccine in the mid-1950s, new cases of poliomyelitis declined dramatically in many industrialized countries.[93] Efforts to completely eradicate the disease started in 1988 and are ongoing.[94]

Circulating vaccine-derived polioviruses

The oral polio vaccine, while highly effective, has the disadvantage that it contains a live virus which has been attenuated so that it cannot cause severe illness. The vaccine virus is excreted in the stool, and in under-immunized communities it can spread from person to person. This is known as circulating vaccine-derived poliovirus (cVDPV) or more simply as variant poliovirus.[13][95]

With prolonged transmission of this kind, the weakened virus can mutate and revert to a form that causes illness and paralysis. Cases of cVDPV now exceed wild-type cases, making it desirable to discontinue the use of the oral polio vaccine as soon as safely possible and instead use other types of polio vaccines.[13][96]

Eradication

See also: Poliomyelitis eradication
 
The decade of the last recorded case of paralytic polio. Since the creation of this image, Nigeria has been certified free of wild polio as of August 2020 and one case was recorded in the US state of New York in July 2022.[97]

A global effort to eradicate polio – the Global Polio Eradication Initiative – began in 1988, led by the World Health Organization, UNICEF, and The Rotary Foundation.[94] Polio is one of only two diseases currently the subject of a global eradication program, the other being Guinea worm disease.[98] So far, the only diseases completely eradicated by humankind are smallpox, declared eradicated in 1980,[99][100] and rinderpest, declared eradicated in 2011.[101] In April 2012, the World Health Assembly declared that the failure to completely eradicate polio would be a programmatic emergency for global public health, and that it "must not happen."[102]

These efforts have hugely reduced the number of cases; from an estimated 350,000 cases in 1988 to a low of 483 cases in 2001, after which it remained at a level of about 1,000–2000 cases per year for a number of years.[103][104]

By 2015, polio was believed to remain naturally spreading in only two countries, Pakistan and Afghanistan,[105][106] although it continued to cause outbreaks in other nearby countries due to hidden or re-established transmission.[107]

Global surveillance for polio takes two forms. Cases of acute flaccid paralysis (AFP) are tested for the presence and type of poliovirus. In addition, environmental and wastewater samples are tested for the presence of poliovirus - this is an effective method of detecting circulating virus which has not given rise to severe symptoms.[108] Here is a summary of both wild polio (WPV) and variant polio (cVDPV) prevalence over the last 5 years:[109]

  • 2019 - 147 cases of WPV1 in Pakistan, and 29 cases in Afghanistan. None were reported elsewhere in the world. cVDPV was detected in 19 countries with 378 confirmed cases.[110]
  • 2020 - 84 WPV1 cases in Pakistan, 56 in Afghanistan. 32 countries reported cVDPV detection, and there were 1,103 cVDPV cases.[110]
  • In 2021, there were just six confirmed cases of wild poliovirus — one in Pakistan, four in Afghanistan, and one in Malawi. The case in Malawi, the country's first in almost three decades and the first in Africa in five years, was seen as a significant setback to the eradication effort.[111] 23 countries detected cVDPV, with 698 cases.[112]
  • In 2022, there were 30 confirmed cases of WPV1 reported to WHO, with two cases in Pakistan and 20 Afghanistan respectively, while eight non-endemic cases were recorded in Mozambique, the first cases in the country since 1992. The Mozambique cases derived from the strain of Pakistani origin that caused two confirmed cases in Malawi in 2021.[113] 24 countries detected cVDPV, with 881 cases.[112]
  • In 2023, twelve cases of WPV1 were reported, six each in Afghanistan and Pakistan. 32 countries reported cVDPV, with 524 cases.[114]

Afghanistan and Pakistan

See also: Polio in Pakistan

The last remaining region with wild polio cases are the South Asian countries Afghanistan and Pakistan.[115]

During 2011, the CIA ran a fake hepatitis vaccination clinic in Abbottabad, Pakistan, in an attempt to locate Osama bin Laden. This destroyed trust in vaccination programs in the region.[116][117] There were attacks and deaths among vaccination workers; 66 vaccinators were killed in 2013 and 2014.[118][119] In Afghanistan, the Taliban banned house-to-house polio vaccination between 2018 and 2021.[120] These factors have set back efforts to eliminate polio by means of vaccination in these countries.[121]

In Afghanistan, 80 cases of polio were reported from 35 districts during 2011. Incidence over the subsequent 10 years has declined to just 4 cases in 2 districts during 2021.[122][123]

In Pakistan, cases dropped by 97 percent from 2014 to 2018;[124] reasons include 440 million dirham support from the United Arab Emirates to vaccinate more than ten million children,[119][125] changes in the military situation, and arrests of some of those who attacked polio workers.[126][127]

Americas

The Americas were declared polio-free in 1994.[128] The last known case was a boy in Peru in 1991.[129] The US Centers for Disease Control and Prevention recommends polio vaccination boosters for travelers and those who live in countries where the disease is endemic.[130]

In July 2022, the US state of New York reported a polio case for the first time in almost a decade in the country; this was attributed to a vaccine-derived strain of the virus.[131]

Western Pacific

In 2000, polio was declared to have been officially eliminated in 37 Western Pacific countries, including China and Australia.[132][133]

Despite eradication ten years earlier, an outbreak was confirmed in China in September 2011, involving a strain common in Pakistan.[134]

In September 2019, the Department of Health of the Philippines declared a polio outbreak in the country after a single case in a 3-year-old girl.[135] In December 2019, acute poliomyelitis was confirmed in an infant in Sabah state, Borneo, Malaysia.[136] Subsequently, a further three polio cases were reported, with the last case reported in January 2020. Both outbreaks were found to be linked instances of vaccine-derived poliomyelitis.[137]

Europe

Europe was declared polio-free in 2002.[138]

Southeast Asia

On 27 March 2014, the WHO announced the eradication of poliomyelitis in the South-East Asia Region, which includes eleven countries: Bangladesh, Bhutan, North Korea, India, Indonesia, Maldives, Myanmar, Nepal, Sri Lanka, Thailand and Timor-Leste.[105] With the addition of this region, 80 per cent of the world population was considered to be living in polio-free regions.[105]

Middle East

In Syria difficulties in executing immunization programs in the ongoing civil war led to a return of polio, probably in 2012,[139] acknowledged by the WHO in 2013.[140][141] 15 cases were confirmed among children in Syria between October and November 2013 in Deir Ezzor. Later, two more cases, one each in rural Damascus and Aleppo, were identified. It was the first outbreak in Syria since 1999. Doctors and international public health agencies report more than 90 cases of polio in Syria, with fears of contagion in rebel areas from lack of sanitation and safe-water services.[142] A vaccination campaign in Syria operated literally under fire and led to the deaths of several vaccinators,[143] but returned vaccination coverage to pre-war levels.[144] Syria is currently free of polio, but is considered "at risk".[145]

In 2024, the Gaza Health Ministry reported that several children have shown symptoms consistent with polio, with laboratory tests confirming that a 10-month-old child is infected with the virus.[146] Prior to the Israel-Hamas conflict, 99% of Gaza's 2.2 million residents were vaccinated against polio, but that rate has since fallen to 86%, according to the WHO.[147] United Nations Secretary-General António Guterres urged for a weeklong cease-fire in Gaza to facilitate vaccinations and prevent a potential polio outbreak, emphasizing the risk faced by many children.[148]

Africa

 
Polio vaccination in Egypt

In 2003, in northern Nigeria – a country that at that time was considered provisionally polio free – a fatwa was issued declaring that the polio vaccine was designed to render children sterile.[149] Subsequently, polio reappeared in Nigeria and spread from there to several other countries. In 2013, nine health workers administering polio vaccine were targeted and killed by gunmen on motorcycles in Kano, but this was the only attack.[150][151] Local traditional and religious leaders and polio survivors worked to revive the campaign,[152] and Nigeria was removed from the polio-endemic list in September 2015 after more than a year without any cases,[153] only to be restored to the list in 2016 when two cases were detected.[154]

Africa was declared free of wild polio in August 2020, although cases of circulating vaccine-derived poliovirus type 2 continue to appear in several countries.[155]

A single case of wild polio that was detected in Malawi in February 2022, and another in Mozambique in May 2022 were both of a strain imported from Pakistan and do not affect the African region's wild poliovirus-free certification status.[156][157]

History

See also: History of poliomyelitis and List of poliomyelitis survivors
 
An Egyptian stele thought to represent a person with polio, 18th Dynasty (1403–1365 BC)

The effects of polio have been known since prehistory; Egyptian paintings and carvings depict otherwise healthy people with withered limbs, and young children walking with canes.[158] The earliest known case of polio is indicated by the remains of a teenage girl discovered in a 4000-year-old burial site in the United Arab Emirates, exhibiting characteristic symptoms of the condition.[159]

The first clinical description was provided by the English physician Michael Underwood in 1789, where he refers to polio as "a debility of the lower extremities".[160] The work of physicians Jakob Heine in 1840 and Karl Oskar Medin in 1890 led to it being known as Heine–Medin disease.[161] The disease was later called infantile paralysis, based on its propensity to affect children.[162]

Before the 20th century, polio infections were rarely seen in infants before six months of age, most cases occurring in children six months to four years of age. Poorer sanitation of the time resulted in constant exposure to the virus, which enhanced a natural immunity within the population. In developed countries during the late 19th and early 20th centuries, improvements were made in community sanitation, including better sewage disposal and clean water supplies. These changes drastically increased the proportion of children and adults at risk of paralytic polio infection, by reducing childhood exposure and immunity to the disease.[163]

Small localized paralytic polio epidemics began to appear in Europe and the United States around 1900.[164] Outbreaks reached pandemic proportions in Europe, North America, Australia, and New Zealand during the first half of the 20th century. By 1950, the peak age incidence of paralytic poliomyelitis in the United States had shifted from infants to children aged five to nine years, when the risk of paralysis is greater; about one-third of the cases were reported in persons over 15 years of age.[165] Accordingly, the rate of paralysis and death due to polio infection also increased during this time.[164] In the United States, the 1952 polio epidemic became the worst outbreak in the nation's history. Of the nearly 58,000 cases reported that year, 3,145 died and 21,269 were left with mild to disabling paralysis.[166] Intensive care medicine has its origin in the fight against polio.[167] Most hospitals in the 1950s had limited access to iron lungs for patients unable to breathe without mechanical assistance. Respiratory centers designed to assist the most severe polio patients, first established in 1952 at the Blegdam Hospital of Copenhagen by Danish anesthesiologist Bjørn Ibsen, were the precursors of modern intensive care units (ICU). (A year later, Ibsen would establish the world's first dedicated ICU.)[168]

The polio epidemics not only altered the lives of those who survived them, but also brought profound cultural changes, spurring grassroots fund-raising campaigns that would revolutionize medical philanthropy, and giving rise to the modern field of rehabilitation therapy. As one of the largest disabled groups in the world, polio survivors also helped to advance the modern disability rights movement through campaigns for the social and civil rights of the disabled. The World Health Organization estimates that there are 10 to 20 million polio survivors worldwide.[169] In 1977, there were 254,000 persons living in the United States who had been paralyzed by polio.[170] According to doctors and local polio support groups, some 40,000 polio survivors with varying degrees of paralysis were living in Germany, 30,000 in Japan, 24,000 in France, 16,000 in Australia, 12,000 in Canada and 12,000 in the United Kingdom in 2001.[169] Many notable individuals have survived polio and often credit the prolonged immobility and residual paralysis associated with polio as a driving force in their lives and careers.[171]

The disease was very well publicized during the polio epidemics of the 1950s, with extensive media coverage of any scientific advancements that might lead to a cure. Thus, the scientists working on polio became some of the most famous of the century. Fifteen scientists and two laymen who made important contributions to the knowledge and treatment of poliomyelitis are honored by the Polio Hall of Fame, which was dedicated in 1957 at the Roosevelt Warm Springs Institute for Rehabilitation in Warm Springs, Georgia, US. In 2008 four organizations (Rotary International, the World Health Organization, the U.S. Centers for Disease Control and UNICEF) were added to the Hall of Fame.[172][173]

World Polio Day (24 October) as an annual day of awareness was established by Rotary International to commemorate the birth of Jonas Salk, who led the first team to develop a vaccine against poliomyelitis.[174]

A global effort to eradicate polio – the Global Polio Eradication Initiative (GPEI) – began in 1988, led by the World Health Organization, UNICEF, and The Rotary Foundation.[94] Since then, international cooperation led by GPEI has reduced polio worldwide by 99 percent, and the campaign is ongoing.[174]

In 2010, wild poliovirus was discovered through importation in 13 different countries. They were Chad, the Democratic Republic of Congo, the Republic of Congo, Kazakhstan, Liberia, Mali, Nepal, Niger, the Russian Federation, Senegal, Tajikistan, Turkmenistan, and Uganda.[175]

In 2021, Types 2 and 3 were fully eradicated from every country, however type 1 cases still remain in Pakistan and Afghanistan.[176] A majority of countries have successfully eradicated polio, with Pakistan and Afghanistan being the last countries with endemic cases of poliovirus.[177] The following countries have been considered polio-free, but not confirmed as of April 2024: Somalia, Djibouti, Sudan, Egypt, Libya, Tunisia, Morocco, Palestine, Lebanon, Syria, Jordan, Saudi Arabia, Bahrain, Qatar, Oman, Yemen, the UAE, Iraq, Kuwait, and Iran.[177]

Research

Since 2018, Global Polio Eradication Initiative (GPEI) has coordinated efforts both to eliminate polio and to research means of improving surveillance and prevention. The At the peak of its work, the programme directly employed 4000 people across 75 countries and managed a budget of nearly U.S. $1 billion.[178]

As of 2021, the GPEI had raised 18 billion dollars in funding,[179] with annual contributions around 800 million to 1 billion dollars. Around 30% of the funding came from the Gates Foundation 30% from developed governments, 27% from countries at risk of polio, and the rest was made up of donations from nonprofits, private funders, and other foundations.[180]

The GPEI has identified six directions for continuing research:[181]

  • Optimizing oral polio vaccine efficacy
  • Developing affordable inactivated polio vaccine
  • Managing risks associated with vaccine-derived polioviruses and vaccine-associated paralytic polio (including OPV cessation)
  • Antivirals
  • Polio diagnostics
  • Surveillance research

Even if polio can be eliminated completely from the world population, vaccination programs should continue for at least ten years.[182] The retention of live poliovirus samples in laboratories and vaccine manufacturing facilities (which carry a risk of escape of the virus) should progressively be reduced. To support these two objectives, vaccines are under development which either utilise a virus-like particle, or which derive from a modified virus which cannot reproduce in a human host.[182]

References

  1. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae Estivariz, Concepcion F.; Link-Gelles, Ruth; Shimabukuro, Tom (2021). "Chapter 18: Poliomyelitis". In Hall, Elisha; Wodi, A. Patricia; Hamborsky, Jennifer; Morelli, Valerie; Schillie, Sarah (eds.). Epidemiology and Prevention of Vaccine-Preventable Diseases (The Pink Book) (14th ed.). Centers for Disease Control and Prevention (CDC, US). Archived from the original on 17 March 2022..
  2. ^ a b "Post-Polio Syndrome Fact Sheet". NIH. 16 April 2014. Archived from the original on 29 July 2011. Retrieved 4 November 2014.
  3. ^ a b c d e f g h i "Poliomyelitis: Key facts". World Health Organisation. 22 July 2019. Archived from the original on 18 April 2017.
  4. ^ "This page allows you to request a table with AFP/polio data". WHO. Archived from the original on 2 April 2015. Retrieved 3 May 2023.
  5. ^ a b c "Disease factsheet about poliomyelitis". European Centre for Disease Prevention and Control. 26 March 2013. Archived from the original on 12 April 2023. Retrieved 12 April 2023.
  6. ^ CDC (29 March 2022). "What is Polio?". Centers for Disease Control and Prevention. Archived from the original on 14 November 2020. Retrieved 24 April 2022.
  7. ^ Underwood, Michael (1789). A Treatise on the Diseases of Children. Vol. 2. London, England: J. Mathews. pp. 53–57.
  8. ^ Daniel TM, Robbins FC, eds. (1999). Polio (1st ed.). Rochester, NY: University of Rochester Press. p. 11. ISBN 978-1-58046-066-8. Archived from the original on 17 June 2016.
  9. ^ Landsteiner, Karl; Popper, Erwin (1909). "Übertragung der Poliomyelitis acuta auf Affen" [Transmission of Poliomyelitis acuta to monkeys]. Zeitschrift für Immunitätsforschung und experimentelle Therapie [Journal for Research on Immunity and Experimental Therapy] (in German). 2 (4): 377–390. Archived from the original on 9 September 2021. Retrieved 9 September 2021.
  10. ^ Wheeler DS, Wong HR, Shanley TP, eds. (2009). Science and practice of pediatric critical care medicine. London: Springer. pp. 10–11. ISBN 978-1-84800-921-9. Archived from the original on 17 June 2016.
  11. ^ "Poliomyelitis". www.who.int. Retrieved 9 August 2024.
  12. ^ World Health Organization (3 January 2023). "Global Wild Poliovirus 2016 - 2022" (PDF). Global Polio Eradication Initiative – World Health Organization. Archived from the original (PDF) on 8 January 2023. Retrieved 3 May 2023.
  13. ^ a b c "Polio Vaccine: Vaccine-Derived Poliovirus | CDC". www.cdc.gov. 6 May 2022. Archived from the original on 27 October 2021. Retrieved 27 June 2022.
  14. ^ a b c "GPEI-OPV Oral polio vaccine". Global Polio Eradication Initiative - World Health Organization. 12 April 2024. Retrieved 12 April 2024.
  15. ^ Falconer M, Bollenbach E (2000). "Late functional loss in nonparalytic polio". American Journal of Physical Medicine & Rehabilitation. 79 (1): 19–23. doi:10.1097/00002060-200001000-00006. PMID 10678598.
  16. ^ a b c d Chamberlin SL, Narins B, eds. (2005). The Gale Encyclopedia of Neurological Disorders. Detroit: Thomson Gale. pp. 1859–70. ISBN 978-0-7876-9150-9.
  17. ^ CDC (29 March 2022). "What is Polio?". Centers for Disease Control and Prevention. Archived from the original on 14 November 2020. Retrieved 24 April 2022.
  18. ^ a b c Leboeuf C (1992). The late effects of Polio: Information For Health Care Providers (PDF). Commonwealth Department of Community Services and Health. ISBN 978-1-875412-05-1. Archived from the original (PDF) on 25 June 2008. Retrieved 23 August 2008.
  19. ^ a b c d e Frauenthal HW, Manning JV (1914). Manual of infantile paralysis, with modern methods of treatment. Philadelphia Davis. pp. 79–101. OCLC 2078290.
  20. ^ Wood LD, Hall JB, Schmidt GD (2005). Principles of Critical Care (3rd ed.). McGraw-Hill Professional. p. 870. ISBN 978-0-07-141640-5.
  21. ^ "Definition of POLIOMYELITIS". www.merriam-webster.com. Retrieved 9 April 2024.
  22. ^ "Polio, n. meanings, etymology". Oxford English Dictionary. 9 April 2024. Retrieved 9 April 2024.
  23. ^ a b c Ryan KJ, Ray CG, eds. (2004). "Enteroviruses". Sherris Medical Microbiology (4th ed.). McGraw Hill. pp. 535–37. ISBN 978-0-8385-8529-0.
  24. ^ Cohen JI (2004). "Chapter 175: Enteroviruses and Reoviruses". In Kasper DL, Braunwald E, Fauci AS, et al. (eds.). Harrison's Principles of Internal Medicine (16th ed.). McGraw-Hill Professional. p. 1144. ISBN 978-0-07-140235-4.
  25. ^ Katz SL, Gershon AA, Krugman S, Hotez PJ (2004). Krugman's infectious diseases of children. St. Louis: Mosby. pp. 81–97. ISBN 978-0-323-01756-5.
  26. ^ Ohri LK, Marquess JG (1999). "Polio: Will We Soon Vanquish an Old Enemy?". Drug Benefit Trends. 11 (6): 41–54. Archived from the original on 4 February 2004. Retrieved 23 August 2008. (Available free on Medscape; registration required.)
  27. ^ "Two out of three wild poliovirus strains eradicated". www.who.int. Archived from the original on 30 October 2019. Retrieved 28 August 2022.
  28. ^ a b c d Kew OM, Sutter RW, de Gourville EM, Dowdle WR, Pallansch MA (2005). "Vaccine-derived polioviruses and the endgame strategy for global polio eradication". Annual Review of Microbiology. 59: 587–635. doi:10.1146/annurev.micro.58.030603.123625. PMID 16153180. Archived from the original on 9 July 2020. Retrieved 30 June 2019.
  29. ^ Gorson KC, Ropper AH (September 2001). "Nonpoliovirus poliomyelitis simulating Guillain-Barré syndrome". Archives of Neurology. 58 (9): 1460–64. doi:10.1001/archneur.58.9.1460. PMID 11559319.
  30. ^ World Health Organization (2016). "Polio vaccines: WHO position paper – March, 2016". Weekly Epidemiological Record. 91 (12): 145–68. hdl:10665/254399. PMID 27039410.
  31. ^ "What is vaccine-derived polio?". www.gavi.org. Archived from the original on 28 August 2022. Retrieved 28 August 2022.
  32. ^ "GPEI-Vaccine-Derived Polioviruses". Archived from the original on 28 August 2022. Retrieved 28 August 2022.
  33. ^ Evans CA (December 1960). "Factors influencing the occurrence of illness during naturally acquired poliomyelitis virus infections". Bacteriological Reviews. 24 (4): 341–52. doi:10.1128/MMBR.24.4.341-352.1960. PMC 441061. PMID 13697553.
  34. ^ Polio and the late effects of polio, Department of Health, State Government of Victoria, Australia, archived from the original on 12 April 2023, retrieved 12 April 2023
  35. ^ Chandra RK (June 1975). "Reduced secretory antibody response to live attenuated measles and poliovirus vaccines in malnourished children". British Medical Journal. 2 (5971): 583–5. doi:10.1136/bmj.2.5971.583. PMC 1673535. PMID 1131622.
  36. ^ Joint Committee on Vaccination and Immunisation, Salisbury A, Ramsay M, Noakes K, eds. (2006). Chapter 26:Poliomyelitis. in: Immunisation Against Infectious Disease, 2006 (PDF). Edinburgh: Stationery Office. pp. 313–29. ISBN 978-0-11-322528-6. Archived from the original (PDF) on 26 March 2009. Retrieved 9 March 2007.
  37. ^ Sauerbrei A, Groh A, Bischoff A, Prager J, Wutzler P (March 2002). "Antibodies against vaccine-preventable diseases in pregnant women and their offspring in the eastern part of Germany". Medical Microbiology and Immunology. 190 (4): 167–72. doi:10.1007/s00430-001-0100-3. PMID 12005329. S2CID 12369344.
  38. ^ He Y, Mueller S, Chipman PR, et al. (April 2003). "Complexes of poliovirus serotypes with their common cellular receptor, CD155". Journal of Virology. 77 (8): 4827–35. doi:10.1128/JVI.77.8.4827-4835.2003. PMC 152153. PMID 12663789.
  39. ^ a b c Yin-Murphy M, Almond JW (1996). "Picornaviruses: The Enteroviruses: Polioviruses". In Baron S, et al. (eds.). Baron's Medical Microbiology (4th ed.). Univ of Texas Medical Branch. ISBN 978-0-9631172-1-2. PMID 21413259. Archived from the original on 7 December 2008.
  40. ^ Todar K (2006). "Polio". Ken Todar's Microbial World. University of Wisconsin – Madison. Archived from the original on 27 April 2010. Retrieved 23 April 2007.
  41. ^ Sabin AB (June 1956). "Pathogenesis of poliomyelitis; reappraisal in the light of new data". Science. 123 (3209): 1151–57. Bibcode:1956Sci...123.1151S. doi:10.1126/science.123.3209.1151. PMID 13337331.
  42. ^ a b c d e Mueller S, Wimmer E, Cello J (August 2005). "Poliovirus and poliomyelitis: a tale of guts, brains, and an accidental event". Virus Research. 111 (2): 175–93. doi:10.1016/j.virusres.2005.04.008. PMID 15885840.
  43. ^ Punsoni, Michael; Lakis, Nelli S.; Mellion, Michelle; de la Monte, Suzanne M. (June 2023). "Post-Polio Syndrome Revisited". Neurology International. 15 (2): 569–579. doi:10.3390/neurolint15020035. ISSN 2035-8377. PMC 10123742. PMID 37092507.
  44. ^ a b c Silverstein A, Silverstein V, Nunn LS (2001). Polio. Diseases and People. Berkeley Heights, NJ: Enslow Publishers. p. 12. ISBN 978-0-7660-1592-0.
  45. ^ a b Gawne AC, Halstead LS (1995). "Post-polio syndrome: pathophysiology and clinical management". Critical Review in Physical Medicine and Rehabilitation. 7 (2): 147–88. doi:10.1615/CritRevPhysRehabilMed.v7.i2.40. Archived from the original on 30 June 2016. Retrieved 30 June 2016. Reproduced online with permission by Lincolnshire Post-Polio Library; retrieved on 10 November 2007.
  46. ^ Young GR (February 1989). "Occupational therapy and the postpolio syndrome". The American Journal of Occupational Therapy. 43 (2): 97–103. doi:10.5014/ajot.43.2.97. PMID 2522741.
  47. ^ Nathanson N, Martin JR (December 1979). "The epidemiology of poliomyelitis: enigmas surrounding its appearance, epidemicity, and disappearance". American Journal of Epidemiology. 110 (6): 672–92. doi:10.1093/oxfordjournals.aje.a112848. PMID 400274.
  48. ^ Karp H (18 March 2005). "A photomicrograph of the thoracic spinal cord depicting degenerative changes due to Polio Type III". Public Health Image Library (PHIL). Centers for Disease Control and Prevention. Archived from the original on 2 February 2014. Retrieved 24 January 2014.
  49. ^ Wallace GS, Oberste SM (13 April 2013). "Chapter 12: Poliomyelitis". Manual for the Surveillance of Vaccine-Preventable Diseases (5th Edition, 2012). Centers for Disease Control and Prevention. Archived from the original on 28 January 2014. Retrieved 24 January 2014.
  50. ^ a b c Professional Guide to Diseases (Professional Guide Series). Hagerstown, MD: Lippincott Williams & Wilkins. 2005. pp. 243–45. ISBN 978-1-58255-370-2.
  51. ^ a b c d Hoyt WG, Miller N, Walsh F (2005). Walsh and Hoyt's clinical neuro-ophthalmology. Hagerstown, MD: Lippincott Williams & Wilkins. pp. 3264–65. ISBN 978-0-7817-4814-8.
  52. ^ "Case definitions for infectious conditions under public health surveillance. Centers for Disease Control and Prevention" (PDF). MMWR. Recommendations and Reports. 46 (RR-10): 1–55. May 1997. PMID 9148133. Archived from the original (PDF) on 5 July 2017. Retrieved 11 November 2007.
  53. ^ a b Hammon WM (1955). "Passive immunization against poliomyelitis". Monograph Series. World Health Organization. 26: 357–70. PMID 14374581.
  54. ^ Hammon WM, Coriell LL, Ludwig EH, McAllister RM, Greene AE, Sather GE, Wehrle PF (September 1954). "Evaluation of Red Cross gamma globulin as a prophylactic agent for poliomyelitis. 5. Reanalysis of results based on laboratory-confirmed cases". Journal of the American Medical Association. 156 (1): 21–27. doi:10.1001/jama.1954.02950010023009. PMID 13183798.
  55. ^ Rinaldo CR (May 2005). "Passive immunization against poliomyelitis: the Hammon gamma globulin field trials, 1951–1953". American Journal of Public Health. 95 (5): 790–99. doi:10.2105/AJPH.2004.040790. PMC 1449257. PMID 15855454.
  56. ^ World Health Organization (2016). "Polio vaccines: WHO position paper – March, 2016". Weekly Epidemiological Record. 91 (12): 145–68. hdl:10665/254399. PMID 27039410.
  57. ^ Spice B (4 April 2005). "Tireless polio research effort bears fruit and indignation". The Salk vaccine: 50 years later/ second of two parts. Pittsburgh Post-Gazette. Archived from the original on 5 September 2008. Retrieved 23 August 2008.
  58. ^ Sabin AB, Boulger LR (1973). "History of Sabin attenuated poliovirus oral live vaccine strains". Journal of Biological Standardization. 1 (2): 115–18. doi:10.1016/0092-1157(73)90048-6.
  59. ^ Sabin AB, Ramos-Alvarez M, Alvarez-Amezquita J, et al. (August 1960). "Live, orally given poliovirus vaccine. Effects of rapid mass immunization on population under conditions of massive enteric infection with other viruses". JAMA. 173 (14): 1521–26. doi:10.1001/jama.1960.03020320001001. PMID 14440553.
  60. ^ a b "A Science Odyssey: People and Discoveries". PBS. 1998. Archived from the original on 26 July 2008. Retrieved 23 August 2008.
  61. ^ a b "Polio Vaccine | IPV Vaccine". Archived from the original on 7 October 2007. Retrieved 1 November 2011. Accessed 16 December 2009.
  62. ^ Fine PE, Carneiro IA (November 1999). "Transmissibility and persistence of oral polio vaccine viruses: implications for the global poliomyelitis eradication initiative". American Journal of Epidemiology. 150 (10): 1001–21. doi:10.1093/oxfordjournals.aje.a009924. PMID 10568615.
  63. ^ Alfaro-Murillo, Jorge A.; Ávila-Agüero, María L.; Fitzpatrick, Meagan C.; Crystal, Caroline J.; Falleiros-Arlant, Luiza-Helena; Galvani, Alison P. (4 April 2020). "The case for replacing the live oral polio vaccine with the inactivated vaccine throughout the Americas". Lancet. 395 (10230): 1163–1166. doi:10.1016/S0140-6736(20)30213-0. ISSN 0140-6736. PMC 8572547. PMID 32247397.
  64. ^ "Poliomyelitis prevention: recommendations for use of inactivated poliovirus vaccine and live oral poliovirus vaccine. American Academy of Pediatrics Committee on Infectious Diseases". Pediatrics. 99 (2): 300–05. February 1997. doi:10.1542/peds.99.2.300. PMID 9024465. Archived from the original on 30 September 2007.
  65. ^ "GPEI-Variant Polio (cVDPV) Cases". Global Polio Eradication Initiative - World Health Organization. 9 April 2024. Retrieved 15 April 2024.
  66. ^ "Eradication of polio – Is Syria being left behind?". sphcm.med.unsw.edu.au. School of Public Health and Community Medicine. Archived from the original on 6 October 2018. Retrieved 27 September 2022.
  67. ^ "WHO: Vaccines for routine use". International travel and health. p. 12. Archived from the original on 6 June 2008. Retrieved 23 August 2008.
  68. ^ Daniel TM, Robbins FC (1997). Polio. Rochester, NY: University of Rochester Press. pp. 8–10. ISBN 978-1-58046-066-8.
  69. ^ Corrado, A.; Ginanni, R.; Villella, G.; Gorini, M.; Augustynen, A.; Tozzi, D.; Peris, A.; Grifoni, S.; Messori, A.; Nozzoli, C.; Berni, G. (March 2004). "Iron lung versus conventional mechanical ventilation in acute exacerbation of COPD". The European Respiratory Journal. 23 (3): 419–24. doi:10.1183/09031936.04.00029304. ISSN 0903-1936. PMID 15065832.
  70. ^ Buncombe, Andrew (22 November 2017). "America's last iron lung users on their lives spent inside obsolete ventilators". The Independent. Archived from the original on 25 May 2022. Retrieved 16 April 2019.
  71. ^ a b c d Neumann DA (August 2004). "Polio: its impact on the people of the United States and the emerging profession of physical therapy" (PDF). The Journal of Orthopaedic and Sports Physical Therapy. 34 (8): 479–92. doi:10.2519/jospt.2004.0301. PMID 15373011. Archived (PDF) from the original on 10 September 2008. Reproduced online with permission by Post-Polio Health International; retrieved on 10 November 2007.
  72. ^ Cuccurullo SJ (2004). Physical Medicine and Rehabilitation Board Review. Demos Medical Publishing. ISBN 978-1-888799-45-3. Archived from the original on 12 October 2007.
  73. ^ Goldberg AI (February 2002). "Noninvasive mechanical ventilation at home: building upon the tradition". Chest. 121 (2): 321–24. doi:10.1378/chest.121.2.321. PMID 11834636.
  74. ^ Miller AH, Buck LS (January 1950). "Tracheotomy in bulbar poliomyelitis". California Medicine. 72 (1): 34–36. PMC 1520308. PMID 15398892.
  75. ^ Wackers, G. (1994). Constructivist Medicine (PhD thesis). Maastricht: Universitaire Pers Maastricht. Archived from the original on 23 December 2007. Retrieved 4 January 2008.
  76. ^ Sandberg A, Hansson B, Stålberg E (November 1999). "Comparison between concentric needle EMG and macro EMG in patients with a history of polio". Clinical Neurophysiology. 110 (11): 1900–08. doi:10.1016/S1388-2457(99)00150-9. PMID 10576485. S2CID 14534071.
  77. ^ Cashman NR, Covault J, Wollman RL, Sanes JR (May 1987). "Neural cell adhesion molecule in normal, denervated, and myopathic human muscle". Annals of Neurology. 21 (5): 481–89. doi:10.1002/ana.410210512. PMID 3296947. S2CID 13102779.
  78. ^ a b Agre JC, Rodríquez AA, Tafel JA (October 1991). "Late effects of polio: critical review of the literature on neuromuscular function". Archives of Physical Medicine and Rehabilitation. 72 (11): 923–31. doi:10.1016/0003-9993(91)90013-9. PMID 1929813.
  79. ^ a b c Trojan DA, Cashman NR (January 2005). "Post-poliomyelitis syndrome". Muscle & Nerve. 31 (1): 6–19. doi:10.1002/mus.20259. PMID 15599928. S2CID 25442322.
  80. ^ a b Grimby G, Einarsson G, Hedberg M, Aniansson A (1989). "Muscle adaptive changes in post-polio subjects". Scandinavian Journal of Rehabilitation Medicine. 21 (1): 19–26. doi:10.2340/165019779891926 (inactive 1 November 2024). PMID 2711135. S2CID 9440972.{{cite journal}}: CS1 maint: DOI inactive as of November 2024 (link)
  81. ^ a b "Poliomyelitis virus (picornavirus, enterovirus), after-effects of the polio, paralysis, deformations". Polio Eradication. Sanofi Pasteur. Archived from the original on 7 October 2007. Retrieved 23 August 2008.
  82. ^ a b Mayo Clinic Staff (19 May 2005). "Polio: Complications". Mayo Foundation for Medical Education and Research (MFMER). Archived from the original on 23 June 2008. Retrieved 26 February 2007.
  83. ^ "Post-Polio Syndrome Fact Sheet: National Institute of Neurological Disorders and Stroke (NINDS)". Archived from the original on 29 July 2011. Retrieved 2 August 2011.
  84. ^ Ramlow J, Alexander M, LaPorte R, Kaufmann C, Kuller L (October 1992). "Epidemiology of the post-polio syndrome". American Journal of Epidemiology. 136 (7): 769–86. doi:10.1093/aje/136.7.769. PMID 1442743.
  85. ^ Lin KH, Lim YW (August 2005). "Post-poliomyelitis syndrome: case report and review of the literature" (PDF). Annals of the Academy of Medicine, Singapore. 34 (7): 447–49. doi:10.47102/annals-acadmedsg.V34N7p447. PMID 16123820. Archived (PDF) from the original on 7 March 2007.
  86. ^ Hsu JD, Michael J, Fisk J, eds. (2008). Orthoses for persons with postpolio syndrome. AAOS Atlas of Orthoses and Assistive Devices. Philadelphia: Mosby/Elsevier. pp. 411–17. ISBN 978-0-323-03931-4. OCLC 152793635. Archived from the original on 13 June 2021. Retrieved 20 July 2021.
  87. ^ Irby SE, Bernhardt KA, Kaufman KR (December 2005). "Gait of stance control orthosis users: the dynamic knee brace system". Prosthetics and Orthotics International. 29 (3): 269–82. doi:10.1080/03093640500238915. PMID 16466156. S2CID 7166949.
  88. ^ Brehm MA, Beelen A, Doorenbosch CA, Harlaar J, Nollet F (October 2007). "Effect of carbon-composite knee-ankle-foot orthoses on walking efficiency and gait in former polio patients". Journal of Rehabilitation Medicine. 39 (8): 651–7. doi:10.2340/16501977-0110. PMID 17896058.
  89. ^ Trevelyan B, Smallman-Raynor M, Cliff A (2005). "The Spatial Dynamics of Poliomyelitis in the United States: From Epidemic Emergence to Vaccine-Induced Retreat, 1910–1971". Ann Assoc Am Geogr. 95 (2): 269–293. doi:10.1111/j.1467-8306.2005.00460.x. PMC 1473032. PMID 16741562.
  90. ^ Yin-Murphy M, Almond JW (1996). "Picornaviruses". In Baron S, et al. (eds.). Picornaviruses: The Enteroviruses: Polioviruses in: Baron's Medical Microbiology (4th ed.). Univ of Texas Medical Branch. ISBN 0-9631172-1-1. PMID 21413259. Archived from the original on 7 December 2008.
  91. ^ a b "Polio: a 20th century epidemic | Science Museum". www.sciencemuseum.org.uk. Retrieved 12 April 2024.
  92. ^ "History of polio vaccination". World health Organization. Retrieved 10 April 2024.
  93. ^ Hinman A (1984). "Landmark perspective: Mass vaccination against polio". JAMA. 251 (22): 2994–6. doi:10.1001/jama.1984.03340460072029. PMID 6371280.
  94. ^ a b c Vaught M (10 April 2015). "Polio Vaccine Celebrates 60th Anniversary". Rotary International. Archived from the original on 17 November 2015. Retrieved 11 November 2015.
  95. ^ "GPEI-Variant Poliovirus (cVDPV)". Global Polio Eradication Initiative. Retrieved 7 August 2024.
  96. ^ "GPEI-Vaccine-Derived Polioviruses". Archived from the original on 28 August 2022. Retrieved 3 September 2022.
  97. ^ "The decade of the last recorded case of paralytic polio by country". Our World in Data. Archived from the original on 13 May 2020. Retrieved 4 March 2020.
  98. ^ Akst J (1 July 2015). "Driven to Extinction". The Scientist. Archived from the original on 18 November 2015. Retrieved 11 November 2015.
  99. ^ "Smallpox". WHO Factsheet. Archived from the original on 21 September 2007. Retrieved 23 August 2008.
  100. ^ "The Smallpox Eradication Programme – SEP (1966–1980)". WHO. Archived from the original on 9 November 2015. Retrieved 11 November 2015.
  101. ^ "No more deaths from rinderpest" (Press release). World Organisation for Animal Health. 25 May 2011. Archived from the original on 24 September 2015. Retrieved 11 November 2015.
  102. ^ World Health Assembly (2012). Poliomyelitis: intensification of the global eradication initiative. Agenda item A65/20 (PDF). Geneva, Switzerland: World Health Organization. Archived (PDF) from the original on 9 November 2013. Retrieved 7 December 2013.
  103. ^ Centers for Disease Control Prevention (CDC) (October 2006). "Update on vaccine-derived polioviruses". MMWR. Morbidity and Mortality Weekly Report. 55 (40): 1093–7. PMID 17035927.
  104. ^ Centers for Disease Control and Prevention (CDC) (May 2008). "Progress toward interruption of wild poliovirus transmission—worldwide, January 2007 – April 2008". MMWR. Morbidity and Mortality Weekly Report. 57 (18): 489–94. PMID 18463607. Archived from the original on 19 June 2017.
  105. ^ a b c "WHO South-East Asia Region certified polio-free". WHO. 27 March 2014. Archived from the original on 27 March 2014. Retrieved 27 March 2014.
  106. ^ "Wild poliovirus type 1 and Circulating vaccine-derived poliovirus cases". Global Polio Eradication Initiative. 23 December 2015. Archived from the original on 24 December 2015. Retrieved 26 December 2015.
  107. ^ Wild Poliovirus case list 2000–2010; data in WHO/HQ as of 9 November 2010 "Emergency appeal for Congo polio outbreak". Archived from the original on 22 December 2010. Retrieved 17 November 2010.
  108. ^ "Surveillance Indicators". Global Polio Eradication Initiative. 14 August 2024. Retrieved 14 August 2024.
  109. ^ "Global Wild Poliovirus 2018–2024" (PDF). Global Polio Eradication Initiative - World Health Organization. 9 April 2024.
  110. ^ a b Bigouette, John Paul; Wilkinson, Amanda L.; Tallis, Graham; Burns, Cara C.; Wassilak, Steven G. F.; Vertefeuille, John F. (27 August 2021). "Progress Toward Polio Eradication — Worldwide, January 2019–June 2021". Morbidity and Mortality Weekly Report. 70 (34): 1129–1135. doi:10.15585/mmwr.mm7034a1. ISSN 0149-2195. PMC 8389387. PMID 34437527.
  111. ^ "GPEI Statement on WPV1 in Malawi: Wild poliovirus type 1 detected in Lilongwe, Malawi" (Press release). Global Polio Eradication Initiative - World Health Organization. 17 February 2022.
  112. ^ a b Lee, Scarlett E. (2023). "Progress Toward Poliomyelitis Eradication — Worldwide, January 2021–March 2023". MMWR. Morbidity and Mortality Weekly Report. 72 (19): 517–522. doi:10.15585/mmwr.mm7219a3. ISSN 0149-2195. PMC 10208367. PMID 37167156.
  113. ^ "GPEI statement on Mozambique WPV1 detection" (Press release). Global Polio Eradication Initiative - World Health Organization. 18 May 2022.
  114. ^ Geiger, Keri (2024). "Progress Toward Poliomyelitis Eradication — Worldwide, January 2022–December 2023". MMWR. Morbidity and Mortality Weekly Report. 73 (19): 441–446. doi:10.15585/mmwr.mm7319a4. ISSN 0149-2195. PMC 11115430. PMID 38753550.
  115. ^ "Global Wild Poliovirus 2018–2024" (PDF). Global Polio Eradication Initiative - World Health Organization. 9 April 2024.
  116. ^ Kennedy J (October 2017). "How Drone Strikes and a Fake Vaccination Program Have Inhibited Polio Eradication in Pakistan: An Analysis of National Level Data". International Journal of Health Services: Planning, Administration, Evaluation. 47 (4): 807–25. doi:10.1177/0020731417722888. ISSN 1541-4469. PMID 28764582. S2CID 25844860. Archived from the original on 20 October 2021. Retrieved 4 May 2021.
  117. ^ McNeil Jr DG (9 July 2012). "C.I.A. Vaccine Ruse May Have Harmed the War on Polio". The New York Times. ISSN 0362-4331. Archived from the original on 10 July 2012. Retrieved 3 July 2020.
  118. ^ Khan T (20 January 2015). "Pakistan's fight against polio clashes with battle against Taliban – The National". Archived from the original on 28 September 2015.
  119. ^ a b The National staff (18 April 2015). "UAE polio campaign vaccinates millions of Pakistani children". Archived from the original on 10 September 2015.
  120. ^ "House-to-house polio vaccination set to recommence across Afghanistan in November". www.unicef.org. Archived from the original on 30 June 2022. Retrieved 30 June 2022.
  121. ^ "Seven shot dead in Pakistan polio attack". BBC News. 20 April 2016. Archived from the original on 4 October 2019. Retrieved 25 January 2021.
  122. ^ World Health Organization, Global Polio Eradication Initiative (30 June 2022). "Afghanistan Polio Eradication Initiative Annual Report 2021" (PDF). Archived (PDF) from the original on 5 June 2022. Retrieved 30 June 2022.
  123. ^ "GPEI-Afghanistan". Archived from the original on 30 June 2022. Retrieved 30 June 2022.
  124. ^ "Nationwide polio campaign starts today". Dawn. 10 December 2018. Archived from the original on 6 July 2020. Retrieved 11 January 2019. It shows that the number of annual polio cases has decreased by 97 per cent from 306 reported in 2014.
  125. ^ The National staff (24 January 2015). "17 million children to be vaccinated against polio in Pakistan". Archived from the original on 10 September 2015.
  126. ^ "Pakistan could beat polio in months, says WHO". BBC News. 16 May 2016. Archived from the original on 16 May 2016. Retrieved 16 May 2016.
  127. ^ "Polio in Pakistan: Drop of 70% recorded this year". BBC News. 3 June 2015. Archived from the original on 4 June 2015.
  128. ^ Centers for Disease Control Prevention (CDC) (October 1994). "Certification of poliomyelitis eradication—the Americas, 1994". MMWR. Morbidity and Mortality Weekly Report. 43 (39): 720–2. PMID 7522302. Archived from the original on 21 May 2017.
  129. ^ "Polio Declared Eliminated from the Americas | History of Vaccines". Archived from the original on 9 July 2020. Retrieved 23 May 2020.
  130. ^ "Guidance to US Clinicians Regarding New WHO Polio Vaccination Requirements for Travel by Residents of and Long-term Visitors to Countries with Active Polio Transmission". CDC. 2 June 2014. Archived from the original on 4 June 2014. Retrieved 4 June 2014.
  131. ^ Kimball, Spencer (4 October 2022). "How polio came back to New York for the first time in decades, silently spread and left a patient paralyzed". CNBC. Archived from the original on 15 November 2022. Retrieved 15 November 2022.
  132. ^ Yamazaki, S.; Toraya, H. (2001). "General News. Major Milestone reached in Global Polio Eradication: Western Pacific Region is certified Polio-Free". Health Education Research. 16 (1): 109–114. Bibcode:2001PDiff..16..110Y. doi:10.1093/her/16.1.109.
  133. ^ D' Souza RM, Kennett M, Watson C (2002). "Australia declared polio free". Communicable Diseases Intelligence Quarterly Report. 26 (2): 253–60. PMID 12206379.
  134. ^ "New polio outbreak hits China - CNN.com". CNN. 21 September 2011. Archived from the original on 1 January 2012.
  135. ^ Paris J (19 September 2019). "PH declares polio outbreak as disease returns after 19 years". Rappler. Manila, Philippines. Archived from the original on 22 September 2019. Retrieved 22 September 2019.
  136. ^ "Malaysia Reports First Case of Polio in 27 Years". VOA News. Associated Press. 9 December 2019. Archived from the original on 8 January 2020. Retrieved 10 December 2019.
  137. ^ Snider, Cynthia J.; Boualam, Liliane; Tallis, Graham; Takashima, Yoshihiro; Abeyasinghe, Rabindra; Lo, Ying-Ru; Grabovac, Varja; Avagyan, Tigran; Aslam, Syeda Kanwal; Eltayeb, Abu Obeida; Aung, Khin Devi; Wang, Xiaojun; Shrestha, Achyut; Ante-Orozco, Carla; Silva, Maria Wilda T. (23 March 2022). "Concurrent outbreaks of circulating vaccine-derived poliovirus types 1 and 2 affecting the Republic of the Philippines and Malaysia, 2019–2021". Vaccine. 41 (Suppl 1): A58–A69. doi:10.1016/j.vaccine.2022.02.022. ISSN 0264-410X. PMC 10546869. PMID 35337673. S2CID 247652342.
  138. ^ "Europe achieves historic milestone as Region is declared polio-free" (Press release). European Region of the World Health Organization. 21 June 2002. Archived from the original on 16 September 2008. Retrieved 23 August 2008.
  139. ^ Whewell T (26 March 2014). "Polio in Syria: An outbreak that threatens the Middle East". BBC News. Archived from the original on 3 July 2015.
  140. ^ "Syria polio cases spread to Damascus and Aleppo – WHO". DNA. 26 November 2013. Archived from the original on 28 November 2013. Retrieved 26 November 2013.
  141. ^ Watkins T (29 October 2013). "WHO: Polio cases confirmed in Syria". CNN.com. Archived from the original on 3 February 2014. Retrieved 24 January 2014.
  142. ^ Sparrow A (20 February 2014). "Syria's Polio Epidemic: The Suppressed Truth". New York Review. Archived from the original on 25 January 2014. Retrieved 23 January 2014. Ninety or so afflicted children may sound like a small number, but they are only a tiny manifestation of an enormous problem, since for each crippled child up to one thousand more are silently infected. Polio is so contagious that a single case is considered a public health emergency. Ninety cases could mean some 90,000 people infected, each a carrier invisibly spreading the disease to others for weeks on end.
  143. ^ Motlagh, Jason (5 March 2015). "Fighting Polio Amid the Chaos of Syria's Civil War". National Geographic. Archived from the original on 5 January 2016.
  144. ^ Westall S (28 January 2015). "Polio immunisation rate in Syria close to pre-war level -WHO". Reuters. Archived from the original on 24 September 2015.
  145. ^ "GPEI-Syrian Arab Republic". Archived from the original on 1 July 2022. Retrieved 1 July 2022.
  146. ^ Pietsch, Bryan (17 August 2024). "Gaza faces public health crisis with first confirmed case of polio". Washington Post. ISSN 0190-8286. Retrieved 18 August 2024.
  147. ^ "WHO, UNICEF call for cease fire in Gaza to allow polio vaccination | CIDRAP". www.cidrap.umn.edu. 16 August 2024. Retrieved 18 August 2024.
  148. ^ Fassihi, Farnaz; Livni, Ephrat (16 August 2024). "The U.N. Calls for a Temporary Truce to Fight Polio in Gaza". The New York Times. ISSN 0362-4331. Retrieved 18 August 2024.
  149. ^ "Polio Eradication Efforts in Nigeria and India". UNICEF. Archived from the original on 25 December 2013. Retrieved 25 December 2013.
  150. ^ "Nigeria polio vaccinators shot dead in Kano". BBC News. 8 February 2013. Archived from the original on 28 December 2014.
  151. ^ "Nigeria marks one year without recorded polio case". BBC News. 24 July 2015. Archived from the original on 24 July 2015.
  152. ^ "Nigeria marks polio-free year, raising global eradication hopes". Reuters. 23 July 2015. Archived from the original on 19 November 2015.
  153. ^ "WHO Removes Nigeria from Polio-Endemic List". WHO. 26 September 2015. Archived from the original on 19 January 2016. Retrieved 8 January 2016.
  154. ^ "Government of Nigeria reports 2 wild polio cases, first since July 2014". WHO. 11 August 2016. Archived from the original on 15 August 2016. Retrieved 15 August 2016.
  155. ^ Guglielmi, Giorgia (28 August 2020). "Africa declared free from wild polio — but vaccine-derived strains remain". Nature. doi:10.1038/d41586-020-02501-3. PMID 32860027. S2CID 221365928. Archived from the original on 1 July 2022. Retrieved 1 July 2022.
  156. ^ "Malawi declares polio outbreak". WHO | Regional Office for Africa. Archived from the original on 16 June 2022. Retrieved 29 June 2022.
  157. ^ "First polio outbreak in 30 years declared in Mozambique". UN News. 18 May 2022. Archived from the original on 1 July 2022. Retrieved 1 July 2022.
  158. ^ Paul JR (1971). A History of Poliomyelitis. Yale studies in the history of science and medicine. New Haven, Conn: Yale University Press. pp. 16–18. ISBN 978-0-300-01324-5.
  159. ^ Renfrew, Colin; Bahn, Paul (2012). Archaeology: Theories, Methods, and Practice (6th ed.). Thames & Hudson. p. 447. ISBN 978-0-500-28976-1.
  160. ^ Underwood M (1789). "Debility of the lower extremities". A treatise on the diseases of children, with general directions for the management of infants from the birth (1789). Vol. 2. London: J. Mathews. pp. 88–91.
  161. ^ Pearce JM (January 2005). "Poliomyelitis (Heine–Medin disease)". Journal of Neurology, Neurosurgery, and Psychiatry. 76 (1): 128. doi:10.1136/jnnp.2003.028548. PMC 1739337. PMID 15608013.
  162. ^ Gould T (1995). "Chapter One". A Summer Plague: Polio and its Survivors. Yale University Press. ISBN 0-300-06292-3.
  163. ^ Robertson S (1993). "Module 6: Poliomyelitis" (PDF). The Immunological Basis for Immunization Series. World Health Organization. Geneva, Switzerland. Archived from the original (PDF) on 2 February 2014. Retrieved 23 August 2008.
  164. ^ a b Trevelyan B, Smallman-Raynor M, Cliff AD (June 2005). "The Spatial Dynamics of Poliomyelitis in the United States: From Epidemic Emergence to Vaccine-Induced Retreat, 1910–1971". Annals of the Association of American Geographers. 95 (2): 269–93. doi:10.1111/j.1467-8306.2005.00460.x. PMC 1473032. PMID 16741562.
  165. ^ Melnick JL (1990). Poliomyelitis. In: Tropical and Geographical Medicine (2nd ed.). McGraw-Hill. pp. 558–76. ISBN 978-0-07-068328-0.
  166. ^ Zamula E (1991). "A New Challenge for Former Polio Patients". FDA Consumer. 25 (5): 21–25. Archived from the original on 20 February 2014.
  167. ^ "Louise Reisner-Sénélar (2009) The Danish anaesthesiologist Björn Ibsen a pioneer of long-term ventilation on the upper airways".
  168. ^ Pincock S (2007). Elsevier (ed.). "Bjørn Aage Ibsen". The Lancet. 370 (9598): 1538. doi:10.1016/S0140-6736(07)61650-X. S2CID 54311450.
  169. ^ a b "After Effects of Polio Can Harm Survivors 40 Years Later". March of Dimes. 1 June 2001. Archived from the original on 25 December 2014. Retrieved 14 November 2014.
  170. ^ Frick NM, Bruno RL (1986). "Post-polio sequelae: physiological and psychological overview". Rehabilitation Literature. 47 (5–6): 106–11. PMID 3749588.
  171. ^ Bruno RL (2002). The Polio Paradox: Understanding and Treating "Post-Polio Syndrome" and Chronic Fatigue. New York: Warner Books. pp. 105–06. ISBN 978-0-446-69069-0.
  172. ^ Skinner W (15 November 2008). "Four added to Polio Hall of Fame at Warm Springs". The Times-Herald (Newnan, GA). Archived from the original on 28 March 2010. Retrieved 29 May 2009.
  173. ^ "CDC Inducted into Polio Hall of Fame". CDC in the News. 23 January 2009. Archived from the original on 24 September 2015.
  174. ^ a b "Announcement: World Polio Day – 24 October 2012". CDC. Centers for Disease Control and Prevention. 19 October 2012. Archived from the original on 12 December 2013. Retrieved 7 December 2013.
  175. ^ "Every Last Child, Annual Report 2010" (PDF). polioeradication.org. 2010. p. 13. Retrieved 3 June 2024.
  176. ^ "Poliomyelitis (polio)". www.who.int. Retrieved 4 June 2024.
  177. ^ a b "Progress towards polio eradication". Our World in Data. Retrieved 4 June 2024.
  178. ^ Aylward, Bruce (2011). "2. Lessons from the late stages of the global polio eradication initiative". In Cochi, Stephen L.; Dowdle, Walter R. (eds.). Disease Eradication in the 21st Century: Implications for Global Health. Cambridge: The MIT Press. pp. 13–24. ISBN 978-0-262-01673-5.
  179. ^ "GPEI-Historical Contributions, 1988-2020".
  180. ^ "Vaccination funding landscape". Givewell.org. Retrieved 20 June 2016.
  181. ^ "GPEI-Research + Innovation". Global Polio Eradication Initiative - World Health Organization. Retrieved 17 April 2024.
  182. ^ a b Lopez Cavestany, Rocio; Eisenhawer, Martin; Diop, Ousmane M.; Verma, Harish; Quddus, Arshad; Mach, Ondrej (April 2024). "The Last Mile in Polio Eradication: Program Challenges and Perseverance". Pathogens. 13 (4): 323. doi:10.3390/pathogens13040323. ISSN 2076-0817. PMC 11053864. PMID 38668278.

Further reading

External videos
  Presentation by David Oshinsky on Polio, June 21, 2006, C-SPAN
  Presentation by Oshinsky on Polio, October 8, 2006, C-SPAN
  •   Media related to Polio at Wikimedia Commons
  •   Quotations related to Polio at Wikiquote
  •   The dictionary definition of polio at Wiktionary
Retrieved from "https://en.wikipedia.org/w/index.php?title=Polio&oldid=1254954741"