Polio

Cause: Polioviruses are members of the family Picornaviridae, genus Enterovirus, in the species enterovirus C, and include 3 serotypes all of which can cause paralysis. Acute paralytic disease may be caused by naturally occurring (wild) polioviruses, and rarely by oral poliovirus (OPV) vaccine viruses.

Illness and treatment: Over 90% of infections are asymptomatic and 4-8% are minor illnesses. Nonparalytic aseptic meningitis with full recovery occurs in 1-2% of infections. Fewer than 1% of infections result in flaccid paralysis. Treatment is supportive.

Sources: Humans are the reservoir. Transmission is mainly through the fecal-oral route. Virus may be present in the stool of an infected person for 3-6 weeks.

Additional risks: Travel by susceptible persons to the few countries where polio is still endemic or to countries still routinely using oral polio vaccine can increase the risk of becoming infected.

Prevention: Universal immunization prevents infection. Only inactivated polio vaccine, IPV, is now used in the United States. This vaccine can prevent paralysis, but does not provide intestinal immunity.

Recent Washington trends: The last endemic transmission of wild polio virus infection in the United States was in 1979; the last case of wild virus infection identified in Washington occurred in 1977. In 1993, a case of vaccine-associated paralytic polio occurred in a state resident after a family member received live oral polio vaccine, which is no longer used in the United States.

Purpose of Reporting and Surveillance

To detect importation of wild poliovirus into the United States
To detect the presence of vaccine-derived poliovirus
To prevent transmission of poliovirus and to distinguish between wild-type polio and vaccine-associated paralytic polio, if a case of poliomyelitis occurs

Legal Reporting Requirements

Health care providers and health care facilities: immediately notifiable to local health jurisdiction
Laboratories: Poliovirus, acute, by IgM positivity or PCR positivity immediately notifiable to local health jurisdiction; specimen submission is required – submission required – isolate or if no isolate available, specimen associated with positive result, within 2 business days
Local health jurisdictions: immediately notifiable to the Washington State Department of Health (DOH) Communicable Disease Epidemiology (CDE): 1-877-539-4344

Paralytic polio is designated “immediately notifiable, extremely urgent”, requiring state and local health authorities to notify CDC within 4 hours of their notification.

Non-paralytic polio is designated “immediately notifiable and urgent” requiring state and local health authorities to notify CDC within 24 hours of their notification.