The Windsor-Essex County Health Unit is alerting local clinicians regarding an increase in the number of reports of children presenting with severe respiratory illness under investigation for AFP. There are confirmed cases of AFP in London, Ontario and in Michigan. The London Health Science Center as well as the Michigan Health Alert Network have also issued advisories to notify of this trend. Cases have been linked to circulating enteroviruses/rhinoviruses, in particular EVD68 and EV-A71. Windsor has not received any reports of AFP at this time.
AFP is a clinical syndrome, typically characterized by rapid onset weakness, which may include respiratory and bulbar weakness. AFP does not include transient weakness (e.g. post ictal). AFP is a broad clinical syndrome with an array of diagnostic possibilities.
Causes of AFP 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.
AFP is under-reported in Ontario with very few cases of AFP reported per year, likely due to lack of awareness of this reporting requirement.
AFP is a disease of public health significance in Ontario and is a mandatory reportable disease among children under 15 years, according to Health Protection and Promotion Act, R.S.O., 1990. All clinically diagnosed, suspected/probable and confirmed cases must be reported to the Health Unit by the next working day. Please contact the Infectious Disease Helpline at 519-258-2146 x 1420.
- Characteristic feature of this disorder are a febrile or respiratory illness before the onset of neurologic symptoms, and a presentation similar to poliomyelitis with limb weakness, variable cranial involvement (e.g., facial weakness, opthalmoplegia, dysarthria or dysphagia), and MRI evidence of gray matter involvement in the spinal cord.
- Other clinical presentation include acute onset of focal weakness or paralysis, characterized as flaccid without other obvious causes (e.g. trauma) and not transient in nature.
- AFP due to Guillane-Barre syndrome is the most common cause of AFP is Canada.
- AFP associated with paralytic polio is characteristic due to its asymmetric distribution (not affecting both sides equally) which affects some muscle groups while sparing others with fever present at onset.
Diagnosis and Testing:
- AFP is a syndrome, which can be caused by a number of pathogens. Laboratory testing of stool, respiratory secretions, cerebrospinal fluid (CSF) and other appropriate clinical specimens is used to rule out poliomyelitis and/or to determine pathogens causing AFP.
- Stool samples- collection of two stool samples within two weeks (up to 6 weeks) after the onset of paralysis for viral studies and campylobacter
- Viral throat swab
- Depending on clinical presentation, a nasopharyngeal swab and/or cerebrospinal fluid may be collected to assist with investigation
- Neurological investigations, as appropriate, such as electromyography, nerve conduction studies, spinal imaging, MRI, CT
- Enterovirus testing can be requested from PHO labs for those with severe respiratory illness or acute neurological conditions
- Serology testing is not recommended for diagnosis of polio or non-polio enterovirus infection
Dr. Wajid Ahmed, MBBS, MAS, MSc, FRCPC
Medical Officer of Health