Poliovirus

Polio, also called poliomyelitis, is a highly contagious, vaccine-preventable disease caused by the poliovirus. Due to widespread polio vaccination, there have been no cases of polio caused by wild-type poliovirus originating from the United States since 1979. However, in July 2022, the CDC was notified of a case of vaccine-derived poliovirus infection in an unvaccinated individual from New York.  Public health experts are working to understand how and where the individual was infected and are evaluating protective measures, such as vaccination services.

Polio has a broad spectrum of clinical manifestations, including asymptomatic infection, flu-like presentation, aseptic meningitis, paralytic disease, and death.  Investigation of a potential case of polio requires immediate notification of state or local health departments. Paralytic poliomyelitis can be diagnosed using clinical criteria alone; however, laboratory confirmation is useful for epidemiologic purposes. Diagnosis of nonparalytic polio is considered definitive when the presence of poliovirus is confirmed using nucleic acid amplification (NAA) or viral culture testing.  Viral culture and NAA testing are useful for diagnosis and subtyping of active polio infection. Serology can be used to detect the presence of neutralizing antibodies to poliovirus. 

Quick Answers for Clinicians

Which laboratory tests are available to determine poliovirus vaccination status?

Serology testing can be used to detect the presence of neutralizing antibodies to poliovirus. The appropriate ARUP test to detect poliovirus antibodies is Poliovirus (Types 1, 3) Antibodies (2014107). Detailed information about the CDC’s recommendations for poliovirus vaccination can be found on the CDC’s website.  In most cases, revaccination is recommended when a patient has an unknown vaccination status. 

How is poliovirus transmitted?

Poliovirus is highly transmissible and spreads through contact with fecally contaminated water sources, improperly washed food, or contaminated objects. The virus replicates in an infected person’s throat and intestines, so transmission can occur through the ingestion of contaminated foods, water, or respiratory droplets (less common). An infected person is contagious immediately before the onset of symptoms and may shed virus in the stool for 4 weeks. Asymptomatic persons may still pass the virus to others. 

Is laboratory testing for poliovirus type 2 available?

Poliovirus type 2 can be identified in culture using ARUP’s Enterovirus Typing assay (0065058). However, this assay cannot discern between wild-type and vaccine-derived strains. For other poliovirus type 2 testing options, contact your local health department. ARUP’s Enterovirus Typing assay (0065058) cannot be performed directly on patient samples. It must be performed on isolated virus from viral culture (refer to test 2006498). Please see ARUP Laboratory Tests for ordering information.

Indications for Testing

Diagnostic testing for poliovirus infection may be appropriate in patients with characteristic signs and symptoms of polio or with a known or suspected exposure to someone with polio. Characteristic symptoms include an acute onset of flaccid paralysis of one or more limbs without sensory or cognitive loss. 

For individuals with an unknown vaccination history, serology may be appropriate to determine the presence of neutralizing antibodies to poliovirus.

Laboratory Testing

The preferred diagnostic testing methods for polio are viral culture or polymerase chain reaction (PCR). The preferred specimen type is stool because pharyngeal and cerebrospinal fluid (CSF) samples often contain less virus. As poliovirus may be intermittently shed, at least two stool specimens collected 24 hours apart and within 14 days of symptom onset are recommended.  If an enterovirus is isolated from culture, serotyping may also be performed to determine the species (eg, poliovirus) and strain (type 1, 2, or 3).

NAA testing is available at ARUP to detect enteroviruses from nonstool sources, but this assay does not distinguish poliovirus from other enteroviruses. In an individual with a clinical presentation compatible with polio and a positive enterovirus by PCR result, polio-specific follow-up testing is recommended. At this time, poliovirus-specific molecular assays are only offered by local public health laboratories and the CDC.

Serology may be used to detect the presence of neutralizing antibodies against poliovirus. A positive titer indicates the presence of neutralizing antibodies to poliovirus, either as a result of vaccination or natural infection. The presence of neutralizing antibodies does not guarantee complete protection against future poliovirus infections, and protection against one type does not imply protection against other types. Observation of a fourfold increase in titer between paired acute and convalescent specimens confirms a diagnosis of poliovirus. 

ARUP Laboratory Tests

Diagnosis

When poliovirus is suspected, please include a request to reflex to Enterovirus Typing (0065058) if culture is positive for enterovirus

When poliovirus is suspected, refer directly to Viral Culture, Non-Respiratory (2006498), and include a request to reflex to this test, Enterovirus Typing (0065058), if culture is positive for enterovirus

Enterovirus typing cannot be performed directly on patient samples; virus isolated from culture is required

Serology

References

Medical Experts

Contributor

Bradley

Benjamin T. Bradley, MD, PhD
Assistant Professor (Clinical), University of Utah
Medical Director, Virology and Molecular Infectious Diseases, ARUP Laboratories
Contributor

Couturier

Marc Roger Couturier, PhD, D(ABMM)
Professor of Pathology (Clinical), University of Utah
Medical Director, Emerging Public Health Crises, Parasitology/Fecal Testing, and Infectious Disease Antigen Testing, ARUP Laboratories
Contributor

Slev

Patricia R. Slev, PhD, D(ABCC)
Associate Professor of Pathology (Clinical), University of Utah
Section Chief, Immunology; Medical Director, Immunology Core Laboratory, ARUP Laboratories