Poliomyelitis (polio)

Poliomyeliltis

Poliomyelitis is a highly contagious infection caused by poliovirus, which is transmitted from person to person through exposure to fecal material or respiratory secretions containing the virus. The incubation period ranges from nine to twelve days. Most poliovirus infections are asymptomatic.

Symptoms

Initial symptoms, when they occur, are similar to those of other viral infections and may include fever, headache, muscle aches, malaise, nausea, vomiting, and sore throat. In roughly one in a thousand cases, poliovirus attacks the spinal cord or brainstem, leading to paralysis in various parts of the body, most often the legs.

Persons at risk of polio

Polio mainly affects children under three years of age.

Vaccination

All children should receive four doses of inactivated polio vaccine at ages 2 months, 4 months, 6-18 months, and 4-6 years. An accelerated immunization schedule is recommended for children who have not completed their polio immunizations and who may be traveling to places where polio still occurs.

Adults who will be traveling to an area where polio is reported and who have never been immunized or whose immunization status is unknown should be given a total of three doses of inactivated polio vaccine separated by at least 4 weeks from each other. Adults who completed the full childhood series of polio immunizations but never had a booster as an adult may be given a single dose of inactivated polio vaccine before entering a polio-endemic area.

Inactivated polio vaccine has essentially replaced oral polio vaccine in the United States because the latter may cause paralytic poliomyelitis, though this is rare. Oral polio vaccine is recommended only for unvaccinated children who will be traveling in less than four weeks to an area where polio is endemic and for mass vaccination campaigns to control polio outbreaks.

Incidence

In 2000, there were fewer than 3500 reported polio cases worldwide. Tens of thousands more children are infected with the virus; while they do not suffer paralysis, they can infect other children.

Polio has been eradicated in the Americas, except for a small outbreak in the Dominican Republic and Haiti in late 2000 which appears to have been controlled. In October 2000, the World Health Organization certified that the Western Pacific region, which includes large parts of Southeast Asia as well as the Pacific Islands, was polio-free. In Europe, only Turkey continues to report a small number of cases. Poliovirus transmission continues to occur in the Indian subcontinent and sub-Saharan Africa, as well as certain countries in the Middle East.

Travelers

Travelers to countries where poliomyelitis is epidemic or endemic are considered to be at increased risk of poliomyelitis and should be fully immunized.

In general, travelers to developing countries (excluding countries in Latin America) should be considered to be at increased risk of exposure to wild poliovirus.

Unvaccinated, or partially vaccinated travelers should complete a primary series with the vaccine that is appropriate to their age and previous immunization status.

Persons who have previously received a primary series may need additional doses of a polio vaccine before traveling to areas with an increased risk of exposure to wild poliovirus.

Poliomyelitis (polio)

Travelers to countries where poliomyelitis is epidemic or endemic are considered to be at increased risk of poliomyelitis and should be fully immunized.

In general, travelers to developing countries (excluding countries in Latin America) should be considered to be at increased risk of exposure to wild poliovirus.

Unvaccinated, or partially vaccinated travelers should complete a primary series with the vaccine that is appropriate to their age and previous immunization status.

Persons who have previously received a primary series may need additional doses of a polio vaccine before traveling to areas with an increased risk of exposure to wild poliovirus.

Diseases