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Original site: www.cdc.gov/polio/hcp/clinical-overview/index.html | RestoredCDC.org is an independent project, not affiliated with CDC or any federal entity. Visit CDC.gov for free official information. Due to archival on January 6, 2025, recent outbreak data is unavailable. Videos are not restored. Access data.restoredcdc.org for restored data. Use of this site implies acceptance of this disclaimer.[More]About Us Report Bug Compare ContentSkip directly to site content Skip directly to search Skip directly to On This PageAn official website of the United States governmentHere's how you knowOfficial websites use .govA .gov website belongs to an official government organization in the United States.Secure .gov websites use HTTPSA lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.PolioExplore TopicsSearchSearchClear InputFor Everyone* About* Vaccination* Fact Sheet* View allHealth Care Providers* Clinical Overview* Investigating a Suspected Case of Polio* Vaccine Recommendations* View allPublic Health* Health Departments: Reporting Cases* Lab Testing* View allView Allsearch close searchsearchPolio Menu ClosePolio MenusearchFor Everyone* About* Vaccination* Fact Sheet* View All HomeHealth Care Providers* Clinical Overview* Investigating a Suspected Case of Polio* Vaccine Recommendations* View AllPublic Health* Health Departments: Reporting Cases* Lab Testing* View AllView All PolioClinical Overview Investigating a Suspected Case of Polio Vaccine Recommendations View AllMay 9, 2024Clinical Overview of PoliomyelitisKey points* Poliovirus is highly contagious and causes polio, also called poliomyelitis, a serious and debilitating disease.* Infection is more common in infants and young children.* If you suspect polio, you should work with your state and local health department to order diagnostic testing.IntroductionPoliovirus is a member of the Enterovirus genus, family Picornaviridae. Enteroviruses are transient inhabitants of the gastrointestinal tract and are stable at acidic pH. Picornaviruses are small, ether-insensitive viruses with an RNA genome.Poliovirus is highly contagious and causes polio, or poliomyelitis, a serious and debilitating disease.Poliovirus serotypes and immunityThere are three poliovirus serotypes (PV1, PV2, and PV3) with minimal heterotypic immunity between them. Immunity to one serotype does not produce significant immunity to the other serotypes.How it spreadsThe virus enters through the mouth and multiplies in the oropharynx and gastrointestinal tract. The virus is usually present in nasopharyngeal secretions for 1 to 2 weeks. It can also be shed in stools for several weeks after infection, even in individuals with minor symptoms or no illness.Polio in children is more commonInfection is more common in infants and young children. Polio occurs at an earlier age among children living in poor hygienic conditions.In temperate climates, poliovirus infections are most common during summer and autumn. In tropical areas, the seasonal pattern is less pronounced.Polio transmission in the United StatesThere has not been a case of wild polio acquired in the United States since 1979. The last imported case of wild polio was in 1993.Clinical featuresExpand AllMost people infected with poliovirus will not have any visible symptoms. About 1 in 4 people will have flu-like symptoms. These symptoms usually last 2 to 5 days, then go away on their own.Fewer than 1% of people will have weakness or paralysis in their arms and/or legs. The paralysis can lead to permanent disability and death.The poliovirus incubation period for nonparalytic symptoms is 3 to 6 days. The onset of paralysis usually occurs 7 to 21 days after infection.Expand AllAcute flaccid paralysisAcute flaccid paralysis (AFP) is a manifestation of a wide spectrum of clinical diseases. Worldwide, children younger than 15 years are at highest risk of developing polio and some other forms of AFP.Even without laboratory-documented poliovirus infection, AFP is expected to occur at a rate of at least 1 per 100,000 children annually. It can result from a variety of infectious and noninfectious causes.Known viral causes of AFP include enterovirus, adenovirus, and West Nile virus. However, AFP caused by these agents is very uncommon in the United States. A study examining AFP in children in California from 1992-1998 found the most common diagnoses were Guillain-Barré Syndrome, unspecified AFP, and botulism.Post-polio syndromeAdults who had paralytic polio during childhood may develop noninfectious post-polio syndrome (PPS) 15 to 40 years later.PPS is characterized by slow, irreversible worsening of muscle weakness, often in the muscle groups involved during the original infection. Muscle and joint pain are also common symptoms.The prevalence and incidence of PPS is unclear. Studies estimate that 25–40% of polio survivors suffer from PPS.PreventionPolio vaccine provides the best protection against polio. CDC recommends that children and adults who are unvaccinated or incompletely vaccinated get polio vaccine to protect against polio.Keep Reading: Polio Vaccine Information for Healthcare ProvidersTesting and diagnosisRapidly investigating suspected polio cases is critical to identifying possible poliovirus transmission and implementing proper control measures.The Manual for the Surveillance of Vaccine-Preventable Diseases provides current guidelines for those involved in VPD surveillance and response. Learn more about epidemiologic, clinical, and laboratory investigations of AFP to rule out poliovirus infection.Keep Reading: Clinical Guidance for Investigating a Suspected Case of PolioCase of polioIn July 2022, CDC was notified of a case of polio in an unvaccinated individual from Rockland County, New York. The case was caused by vaccine-derived poliovirus type 2. CDC consulted with the New York State Department of Health on their investigation.This has not changed CDC's recommendations for polio vaccination. CDC still urges everyone who is not fully vaccinated to complete the polio vaccination series as soon as possible.Reporting suspected casesPolio is a reportable condition. Know what to do if you suspect your patient may have a case of polio.Keep Reading: Clinical Guidance for Investigating a Suspected Case of PolioCase definitionsA probable case of polio is defined as an acute onset of flaccid paralysis of one or more limbs with decreased or absent tendon reflexes in the affected limbs, without other apparent cause, and without sensory or cognitive loss.Paralysis usually begins in the arm or leg on one side of the body (asymmetric) and then moves towards the end of the arm or leg (progresses to involve distal muscle groups). This is described as descending paralysis.Rule out polioAlthough poliovirus is no longer endemic in the United States, healthcare professionals should rule out poliovirus infection in cases of unexplained AFP that are clinically compatible with polio (particularly those with anterior myelitis). This ensures that any importation of poliovirus is quickly identified and investigated.Read MMWR case study on AFPMany patients with AFP will have a lumbar puncture and analysis of cerebrospinal fluid (CSF) performed as part of their evaluation. Detection of poliovirus in CSF from confirmed polio cases is uncommon. A negative CSF test result cannot be used to rule out polio.Consider polio in patients with polio-like symptoms, especially if the person:* Is unvaccinated.* Is incompletely vaccinated.* Recently traveled abroad to a place where polio still occurs.* Was exposed to a person who recently traveled to one of these areas.Only healthcare workers with evidence of complete polio vaccination should attend to the patient.On This Page* Introduction* How it spreads* Clinical features* Prevention* Testing and diagnosis* Case of polio* Reporting suspected cases* Case definitionsRelated PagesInvestigating a Suspected Case of PolioRelated Pages** View AllBack to Top* Investigating a Suspected Case of Polio* Vaccine RecommendationsView All PolioInvestigating a Suspected Case of PolioMay 9, 2024Sources Print ShareFacebook LinkedIn Twitter SyndicateContent Source:National Center for Immunization and Respiratory Diseases; Division of Viral DiseasesRelated PagesInvestigating a Suspected Case of PolioRelated Pages** View All* Investigating a Suspected Case of Polio* Vaccine RecommendationsView All PolioBack to TopPolioPolio was once one of the most feared diseases in the United States. Thanks to the polio vaccine, wild poliovirus has been eliminated in this country.View AllFor Everyone* About* Vaccination* Fact SheetHealth Care Providers* Clinical Overview* Investigating a Suspected Case of Polio* Vaccine RecommendationsPublic Health* Health Departments: Reporting Cases* Lab TestingSign up for Email UpdatesContact UsContact Us* Call 800-232-4636* Contact CDCAbout CDCAbout CDC* Pressroom* Organization* Budget & Funding* Careers & JobsPolicies* Accessibility* External Links* Privacy* Web Policies* FOIA* OIG* No Fear Act* Nondiscrimination* Vulnerability Disclosure PolicyLanguagesLanguages* EspañolLanguage Assistance* Español* 繁體中文* Tiếng Việt* 한국어* Tagalog* Русский* العربية* Kreyòl Ayisyen* Français* Polski* Português* Italiano* Deutsch* 日本語* فارسی* EnglishArchive* CDC Archive* Public Health PublicationsContact UsContact Us* Call 800-232-4636* Contact CDCAbout CDC* Pressroom* Organization* Budget & Funding* Careers & Jobs* About CDCPolicies* Accessibility* External Links* Privacy* Web Policies* FOIA* OIG* No Fear Act* Nondiscrimination* Vulnerability Disclosure PolicyLanguagesLanguages* EspañolLanguage Assistance* Español* 繁體中文* Tiếng Việt* 한국어* Tagalog* Русский* العربية* Kreyòl Ayisyen* Français* Polski* Português* Italiano* Deutsch* 日本語* فارسی* EnglishArchive* CDC Archive* Public Health PublicationsHHS.gov USA.gov
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