Poliomyelitis

FAQs for Health Care Providers

Poliomyelitis Risk, Diagnosis, and Treatment in Afghan Evacuees

Have there been confirmed cases in the Afghan evacuees? No

Polio is still endemic in Afghanistan, and there have been confirmed cases of AFP.

All eligible Afghan refugees who have transited through U.S. military bases prior to arrival in their new communities are receiving polio vaccines, including all adults who are receiving a single IPV. Afghan refugees who have bypassed the military bases have not been updated or received adult boosters.

Epidemiology

Polio is transmitted year-round in warm climates and is seasonal during the summer and fall in more temperate regions. Prior to the industrial revolution and improved sanitation, nearly all people were infected during infancy. As sanitation improved, fecal-oral spread decreased, and individuals were exposed later in childhood when they were more likely to develop AFP. This ultimately led to epidemics of paralytic disease and the pursuit of global polio eradication. Wild poliovirus serotype 2 was eradicated in 1999 and serotype 3 has been considered eradicated since 2019. Type 1 poliovirus now accounts for all wild poliovirus cases. Afghanistan is currently one of two countries where wildtype polio persists (the other is Pakistan; Nigeria was declared polio-free in 2020). In addition to wildtype polio, Afghanistan has circulating vaccine-derived poliovirus type 2 (cVDPVs).

The prolonged conflict in Afghanistan has made vaccination efforts difficult. The number of cases and infected districts has been rising since 2018. There were 21 cases in 2018, 29 cases in 2019 and 38 cases in 2020. In 2020, wild poliovirus transmission in Afghanistan spread from the Southern, Southeastern and Eastern regions to the North and Northwest parts of the country. In the past 12 months Afghanistan has reported 11 wild polio cases and 261 circulating VDPV-2 cases as of August 27, 2021. There have been known cases of AFP throughout the country.

When should I consider poliomyelitis induced acute flaccid myelitis?

Clinical Presentation

Most poliovirus infections are asymptomatic or manifest as a minor, nonspecific flu-like illness (~90%). The incubation period is 3-6 days for non-paralytic disease and 7-21 days for paralytic poliomyelitis. CNS infection can manifest as acute flaccid myelitis (~1% of infections) and aseptic meningitis (4-8% of infected children). In classic paralytic polio, children present with a history of several days of minor illness characterized by fever, sore throat, headache, nausea, constipation, and malaise. After the acute symptoms resolve there are generally 1 to 3 days without symptoms. The subsequent onset of paralysis is characterized by 1) decreased to absent reflexes of the affected limbs, typically in an asymmetric pattern, and 2) a rapid loss of motor function in one or more extremities over a period of several hours with proximal muscles more likely to be affected than distal muscles. Brainstem involvement impacting the 9^th-12^th cranial nerves can lead to respiratory compromise, known as “bulbar poliomyelitis.” The acute paralysis symptoms peak within 5 days. Over time, additional sequelae can occur including bladder and bowel dysfunction and, upper motor neuron signs such as hypertonia, rigidity, or spasticity. Sensory abnormalities are rare. CSF findings are typical of viral meningitis.

AFP is a manifestation of a wide spectrum of clinical diseases (differential diagnosis) and is not a national notifiable disease in the United States, but it is reportable to many states. Even in the absence of poliovirus infection, AFP occurs at an incidence of 1-6 cases per 100,000 children under the age of 15 years. Typical characteristics of AFP are asymmetrical, usually involving one leg or arm (rarely affecting both limbs), and may include muscle atrophy, fever onset, respiratory insufficiency, tingling of the palms/soles of the feet, cramps, sensory loss and loss of bladder control, weakness of the muscles of respiration and swallowing. The most common causes in children younger than 15 years of age in the United States are Guillain-Barre syndrome and botulism. Other causes of AFM include the sequelae of viral infections such as enteroviruses, adenoviruses, and West Nile virus. No etiology is identified in many cases (~20%). Polio should be considered in any patient with unexplained AFP.

Is the poliovirus contagious? Yes

Poliovirus enters the body through the mouth. It spreads through feces of an infected person or, less commonly, via droplets from a sneeze or cough. The wild virus persists in the throat for 1 to 2 weeks and in the feces for 3 to 6 weeks. Polio can contaminate food and water in unsanitary conditions. An infected person can spread the infection immediately before symptoms appear and up to 6 weeks after symptoms have appeared. Infected individuals who are asymptomatic can also spread the infection.

Are there special infectious disease precautions?

• Contact/enteric and droplet precautions are recommended for any suspect case

• Any patient for whom there is concern for acute flaccid myelitis requires notification to the State Health Department who will collaboration with the CDC (see “Case notification to CDC”)

• Persons who will be dwelling in host households with guest Afghan refugees should be up to date on their poliovirus vaccine series. Adults dwelling in these households should have at least 1 adult booster of IPV prior to arrival of the guest family.

How do I diagnose poliomyelitis?

A Probable Case of Poliomyelitis 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 and moves toward the distal end of the arm or leg —termed “descending paralysis.” Any evacuee from Afghanistan with this presentation should be treated as a probable case of polio and should be approached as follows:

• Promptly isolate the patient to avoid transmission

• Immediately report the suspect case to the Minnesota Department of Health. A confirmed paralytic poliomyelitis case needs to be reported to CDC within 4 hours of meeting notification criteria.

• Thorough evaluation for an alternative etiology for AFP.

• Obtain specimens for diagnostic testing for poliovirus detection (PCR), viral isolation and intratypic differentiation as early as possible, including two stool specimens and two throat swab specimens at least 24 hours apart, ideally within 14 days of symptom onset.

For more information see CDC poliomyelitis guidelines for epidemiologic, clinical, and laboratory investigations of AFP to rule out poliovirus infection.

Notes on the diagnosis of poliomyelitis:

• CSF can resemble aseptic meningitis (elevated WBC from 10-200 cells/mm3 with a lymphocytic predominance, and mild to moderate protein elevation (40-50 mg/dL). Detection of poliovirus in CSF from confirmed polio cases is uncommon, and a negative CSF test result cannot be used to rule out polio.

• A CBC is typically normal

What is the treatment for Poliomyelitis?

Treatment is supportive.

Resources and References

• CDC Afghan poliovirus resources including translated information sheets for patients

• CDC Global Immunization, what is polio?

• CDC Polio for Healthcare Providers

• AAP Red Book. Poliovirus infection

• Poliomyelitis StatPearls. NCBI.

• European Centre for Disease Prevention and Control. Poliomyelitis Fact Sheet

Contributors

Jacob Stauffer BA

Kristen Bastug MD

Cindy Howard MD

William Stauffer MD