SynonymsPolio, infantile paralysis
Polio lores134.jpg
A man with a smaller right leg due to poliomyelitis
SpecialtyNeurology, Infectious disease
SymptomsMuscle weakness resulting in an inability to move[1]
ComplicationsPost-polio syndrome[2]
Usual onsetFew hours to days[1][3]
CausesPoliovirus spread by fecal-oral route[1]
Diagnostic methodFinding the virus in the feces or antibodies in the blood[1]
PreventionPolio vaccine[3]
TreatmentSupportive care[3]
Frequency113 people (2017)[4]

Poliomyelitis, often called polio or infantile paralysis, is an infectious disease caused by the poliovirus.[1] In about 0.5 percent of cases there is muscle weakness resulting in an inability to move.[1] This can occur over a few hours to a few days.[1][3] The weakness most often involves the legs but may less commonly involve the muscles of the head, neck and diaphragm.[1] Many people fully recover.[1] In those with muscle weakness about 2 to 5 percent of children and 15 to 30 percent of adults die.[1] Another 25 percent of people have minor symptoms such as fever and a sore throat and up to 5 percent have headache, neck stiffness and pains in the arms and legs.[1][3] These people are usually back to normal within one or two weeks.[1] In up to 70 percent of infections there are no symptoms.[1] Years after recovery post-polio syndrome may occur, with a slow development of muscle weakness similar to that which the person had during the initial infection.[2]

Poliovirus is usually spread from person to person through infected fecal matter entering the mouth.[1] It may also be spread by food or water containing human feces and less commonly from infected saliva.[1][3] Those who are infected may spread the disease for up to six weeks even if no symptoms are present.[1] The disease may be diagnosed by finding the virus in the feces or detecting antibodies against it in the blood.[1] The disease only occurs naturally in humans.[1]

The disease is preventable with the polio vaccine; however, multiple doses are required for it to be effective.[3] The US Centers for Disease Control and Prevention recommends polio vaccination boosters for travelers and those who live in countries where the disease is occurring.[5] Once infected there is no specific treatment.[3] In 2016, there were 37 cases of wild polio and 5 cases of vaccine-derived polio.[3][6] This is down from 350,000 wild cases in 1988.[3] In 2014 the disease was only spreading between people in Afghanistan, Nigeria, and Pakistan.[3] In 2015 Nigeria had stopped the spread of wild poliovirus but it reoccurred in 2016.[7][8]

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] and the virus that causes it was first identified in 1908 by the Austrian immunologist Karl Landsteiner.[9] Major outbreaks started to occur in the late 19th century in Europe and the United States.[1] In the 20th century it became one of the most worrying childhood diseases in these areas.[10] The first polio vaccine was developed in the 1950s by Jonas Salk.[11] In 2013 the World Health Organization hoped that vaccination efforts and early detection of cases would result in global eradication of the disease by 2018.[12]

Signs and symptoms

Outcomes of poliovirus infection
Outcome Proportion of cases[1]
No symptoms 72%
Minor illness 24%
Nonparalytic aseptic
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 which 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.[13] In most people with a normal immune system, a poliovirus infection is asymptomatic. Rarely, the infection produces minor symptoms; these may include upper respiratory tract infection (sore throat and fever), gastrointestinal disturbances (nausea, vomiting, abdominal pain, constipation or, rarely, diarrhea), and influenza-like illness.[1]

The virus enters the central nervous system in about 1 percent of infections. Most patients with CNS involvement develop nonparalytic aseptic meningitis, with symptoms of headache, neck, back, abdominal and extremity pain, fever, vomiting, lethargy, and irritability.[14][15] About one to five in 1000 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.[16] Depending on the site of paralysis, paralytic poliomyelitis is classified as spinal, bulbar, or bulbospinal. 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.[17]

Other Languages
Afrikaans: Poliomiëlitis
Alemannisch: Poliomyelitis
العربية: شلل الأطفال
aragonés: Poliomielitis
asturianu: Poliomielitis
azərbaycanca: Poliomielit
বাংলা: পোলিও
башҡортса: Полиомиелит
беларуская: Поліяміэліт
беларуская (тарашкевіца)‎: Поліяміэліт
български: Полиомиелит
català: Poliomielitis
Чӑвашла: Полиомиелит
čeština: Dětská obrna
Cymraeg: Poliomyelitis
dansk: Polio
Deitsch: Polio
Deutsch: Poliomyelitis
ދިވެހިބަސް: ވާބަލި
español: Poliomielitis
Esperanto: Poliomjelito
euskara: Poliomielitis
فارسی: فلج اطفال
français: Poliomyélite
galego: Poliomielite
ગુજરાતી: પોલિયો
한국어: 소아마비
Hausa: Polio
հայերեն: Պոլիոմիելիտ
Bahasa Indonesia: Poliomielitis
íslenska: Mænusótt
italiano: Poliomielite
қазақша: Полиомиелит
kurdî: Îflîcî
Кыргызча: Полиомиелит
latviešu: Poliomielīts
lietuvių: Poliomielitas
lingála: Ebúkabuka
Lingua Franca Nova: Polio
македонски: Детска парализа
മലയാളം: പോളിയോ
मराठी: पोलियो
Bahasa Melayu: Polio
Nederlands: Poliomyelitis
norsk nynorsk: Poliomyelitt
occitan: Poliomieliti
oʻzbekcha/ўзбекча: Poliomiyelit
ਪੰਜਾਬੀ: ਪੋਲੀਓ
پنجابی: پولیو
پښتو: گوزڼ
Piemontèis: Pòlio
português: Poliomielite
română: Poliomielită
русский: Полиомиелит
саха тыла: Полиомиелит
sicilianu: Poliomilìti
Simple English: Poliomyelitis
slovenčina: Detská obrna
slovenščina: Otroška paraliza
српски / srpski: Полиомијелитис
srpskohrvatski / српскохрватски: Dječja paraliza
Basa Sunda: Polio
suomi: Polio
svenska: Polio
Tagalog: Polio
татарча/tatarça: Полиомиелит
తెలుగు: పోలియో
Türkçe: Çocuk felci
Türkmençe: Poliomiýelit
українська: Поліомієліт
اردو: پولیو
Tiếng Việt: Bại liệt
Winaray: Poliomyelitis
žemaitėška: Puoliuomelėts