Acute Flaccid Paralysis (AFP)

Reporting Obligations

Suspected cases must be reported immediately by phone to the Thunder Bay District Health Unit at 625-5930 or toll-free 1-888-294-6630, ext. 5930 (Monday-Friday, 8:30am to 4:30pm). After hours and on weekends/holidays call Thunder Bay Answering Service at (807) 624-1280.

Enterovirus D68 (EV-D68) testing in cases of Acute Flaccid Paralysis (October, 2022)



Aetiologic Agent:

AFP is a clinical syndrome, typically characterized by rapid onset weakness, which may include respiratory and bulbar weakness. AFP is a broad clinical syndrome with an array of diagnostic possibilities, and may be the result of infectious or non-infectious agents. Surveillance is conducted in an attempt to identify cases of AFP and to investigate all reported cases for evidence to rule out poliomyelitis (polio), which is essential for maintaining Canada’s polio-free status.

AFP may be caused by a number of agents. The immune mediated condition Guillain-Barré Syndrome (GBS) is the most common cause of AFP in Canada. The causes of AFP, some of which lead to GBS, include, but are not limited to, enteroviruses (including poliovirus), adenoviruses, acute West Nile virus infection, Campylobacter spp., transverse myelitis, peripheral neuropathy, acute non-bacterial meningitis, brain abscess, China syndrome, post-polio sequelae, tick paralysis, myasthenia gravis, porphyria and botulism. Poliomyelitis must be distinguished from other paralytic conditions by isolation of poliovirus from stool.

Clinical Presentation:

Acute onset of focal weakness or paralysis, characterized as flaccid without other obvious cases (e.g., trauma).

The most characteristic feature of AFP associated with paralytic polio is its asymmetric distribution (not affecting both sides equally), which affects some muscle groups while sparing others, with fever present at onset. The most typical pattern is involvement of one leg only, or on arm, although this occurs less often. It is less common for both legs or both arms to be affected.

AFP due to Guillain-Barré Syndrome (GBS) may present as symmetrical paralysis and may progress for up to 10 days.

Modes of Transmission:

Depends on causative agent.

Incubation Period:

Depends on the causative agent.

Period of Communicability:

Varies, depending on causative agent


Risk Factors/Susceptibility

Depends on causative agent.


Diagnosis & Laboratory Testing

Clinically confirmed case: Acute onset of focal weakness or paralysis characterized as flaccid (reduced tone) without other obvious cause (e.g. trauma) in children <15 years old. Cases of Guillain-Barré Syndrome (GBS) should be included as cases of Acute Flaccid Paralysis (AFP). Transient weakness (e.g. post-ictal weakness) should not be reported.

AFP is a syndrome which can be caused by a number of pathogens. The following laboratory testing (of stool, respiratory secretions, cerebrospinal fluid (CSF) and other appropriate clinical specimens) is used to rule out poliomyelitis and/or determine pathogens causing AFP:

• Stool samples - collection of two stool samples within two weeks (up to six weeks) after the onset of paralysis for viral studies and campylobacter

• Viral throat swab

  • Serology testing is not recommended for diagnosis of polio or non-polio enterovirus infection
  • Depending on the clinical presentation, a nasopharyngeal swab, and/or cerebrospinal fluid (CSF) may be collected to assist with the investigation
  • Neurologic investigations, as appropriate, should take place (electromyography, nerve conduction studies, MRI, CT)


Treatment & Case Management

Treatment is under the direction of the attending health care provider.

Routine Practices are recommended for hospitalized cases and additional precautions would depend on the causative organism.

Immediate case investigation and specimen collection is essential by Public Health staff to rule out polio as a source of infection, maintain Canada’s polio-free certification status, and determine the source of infection.



  1. Ministry of Health and Long Term Care, Infectious Diseases Protocol - Appendix 1 (2022) Acute Flaccid Paralysis


Additional Resources

Public Health Ontario. Enterovirus D68 (includes AFP Testing and Reporting) 

Heymann, D.L. Control of Communicable Disease Manual (19th Ed.). Washington, American Public Health Association, 2008

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