Skip Navigation LinksSkip Navigation Links
Centers for Disease Control and Prevention
Safer Healthier People
Blue White
Blue White
bottom curve
CDC Home Search Health Topics A-Z spacer spacer
Blue curve MMWR spacer

Imported Paralytic Poliomyelitis -- United States, 1986

In May 1986, a 29-year-old California woman contracted paralytic poliomyelitis while traveling in Asia. She had worked and traveled in Nepal from January through May 2, and she visited Burma between May 3 and May 9. On May 10, she traveled to Thailand, where she had onset of fever (a temperature of 102 F), malaise, and a feeling of weakness lasting 1 day. On May 16, she again had symptoms: fever (a temperature of 104.2 F), headache, and low back pain. On May 17, she experienced weakness in the lower extremities (right more than left), constipation, and urinary retention. On May 19, she was unable to walk and was hospitalized in Bangkok. A flaccid paralysis of the lower extremities without sensory or bulbar involvement was noted. Cerebrospinal fluid contained 90 leukocytes, of which 93% were lymphocytes.

The patient returned to the United States on June 6, confined to a wheelchair. On examination, she was noted to have flaccidity and no deep-tendon reflexes in the right lower extremity. Her sensory modalities were intact; constipation and urinary retention had resolved. Poliovirus type 1 was isolated from stool collected on June 22 and subsequently characterized as "wild-like" by genomic sequencing (1). Electromyography and nerve-conduction studies performed on June 26 were consistent with axonal neuropathy of poliomyelitis. The results of serologic tests for immunoglobulin IgG, IgA, and IgM were within normal ranges. At 60 days after the onset of weakness, she had residual paralysis of the right leg below the knee.

The patient had a vaccination history of three doses of inactivated poliovirus vaccine (IPV) in the late 1950s and one "sugar cube" (not known whether it contained a monovalent (MOPV) or a trivalent oral poliovirus vaccine (OPV)) at a mass clinic in the early 1960s. The patient had traveled previously in Asia and elsewhere, but had not received any doses of poliovirus vaccine before any departures. Reported by J Jones, Placer County Health Officer, J Chin, State Epidemiologist, California Dept of Health Svcs; Div of Immunization, Center for Prevention Services, CDC.

Editorial Note

Editorial Note: The last cases of paralytic poliomyelitis acquired in the United States and caused by wild poliovirus occurred in 1979. From 1980 through 1985, four reported cases of paralytic poliomyelitis caused by wild virus occurred among U.S. citizens--all persons returning from developing countries. These imported cases represent 7% of the 55 cases of paralytic poliomyelitis reported during the 6-year period 1980-1985. The other 51 cases were vaccine associated. During the preceding 6-year period (1974-1979), nine (12%) of 78 reported cases of paralytic poliomyelitis were imported. Of the 13 persons who had imported cases reported between 1974 and 1985, six (46%) were over 18 years of age. The vaccination status of the 13 patients was as follows:

  1. seven had no history of poliovirus vaccination;

  2. four had received one or two doses of poliovirus vaccine (one had had two doses of OPV; two, one dose of OPV; and one, one dose of IPV); and

  3. two had completed at least a primary series (one with three doses of OPV and the other with five doses of IPV, three doses of MOPV, and one dose of OPV).

In addition, some inappropriately immunized U.S. residents and others may become infected asymptomatically while in an area with endemic poliomyelitis and may excrete wild polio virus temporarily after entering the United States (2).

Worldwide, 24,275 cases of paralytic poliomyelitis were reported to the World Health Organization (WHO) in 1984 (3). WHO's Southeast Asia region accounted for 15,167 cases (63% of the world total); followed by 4,513 cases (19%) in the Western Pacific region; 1,959 cases (8%) in the Eastern Mediterranean region; 1,833 cases (8%) in the African region; 571 cases (2%) in the Americas; and 238 cases (1%) in Europe. The global surveillance data doubtless reflect substantial underreporting, but provide useful information on trends.

The widespread use of OPV through the WHO Expanded Program on Immunization (EPI) is probably responsible for the observed downward trend in the incidence of poliomyelitis throughout the world--and thus for the probable reduction in recent years of the risk that individual travelers would be exposed to wild virus in some countries. Conversely, the trend among U.S. citizens toward more frequent international travel may lead to a greater overall risk of exposure to wild poliovirus. In 1983, an estimated 5 million U.S. citizens visited developing countries.

Travelers to countries with endemic or epidemic poliomyelitis should be fully vaccinated (3,4,5). The only countries currently considered free of endemic wild poliovirus circulation are the United States, Canada, Japan, Australia, New Zealand, and most of Eastern and Western Europe. Before visiting other countries, every traveler should have received, at a minimum, a complete primary series of vaccinations (Table 1). In addition, the Immunization Practices Advisory Committee (ACIP) recommends that persons who have previously completed a primary series receive an additional dose of poliovirus vaccine, generally as OPV, before travel (4).

Persons who have not had a primary series and who have less than 4 weeks before beginning international travel should receive one dose of OPV regardless of age. Such travelers who are under 18 years of age should complete the primary series, at the recommended intervals, whether they remain in the foreign country or return to the United States. Persons 18 years and older should complete the primary series only if they remain in the foreign country or plan to travel again to a country with endemic poliomyelitis.

If at least 4 weeks remain before departure, inadequately vaccinated persons 18 years of age and older should receive, at intervals of no less than 4 weeks, additional doses of IPV up to the four recommended to complete a primary series. IPV is preferred to OPV for adults--especially those with no history of poliovirus vaccination, because the risk of vaccine-associated paralysis following OPV is slightly higher for adults than for children.

If time permits, infants and children under 2 years of age traveling to a country with endemic disease should receive at least three doses of OPV, since virtually all persons vaccinated with three doses seroconvert to all three poliovirus serotypes (6). Intervals between doses may be reduced to 4 weeks to maximize immunization status before departure. If the child is under 6 weeks of age, a dose of OPV should be given before travel, but should not be counted as part of the three-dose primary series (3). Thereafter, if the infant remains in a country with endemic disease, the primary schedule recommended by the EPI, three doses given at 4-week intervals, should be followed (7).

Poliomyelitis among travelers is preventable. Therefore, it is important that health-care providers, tour operators, and travel agents alert travelers to the potential risk of paralytic poliomyelitis in developing countries and that increased efforts be made to comply with published poliomyelitis vaccination recommendations (4,5,8,9).


  1. Rico-Hesse R, Pallansch MA, Nottay BK, Kew OM. Natural distribution of wild type 1 poliovirus genotypes. In: Brinton MA, Rueckert R, eds. Positive strand RNS viruses. UCLA Symposia on Molecular and Cellular Biology, new series, vol. 54. New York: Alan R. Liss, 1986.

  2. Paul JR. Epidemiology of poliomyelitis. In: Debre R, et al. Poliomyelitis. Geneva: WHO Monograph Series. 1955;26:9-29.

  3. WHO. Poliomyelitis in 1984. Part I. Weekly Epidemiological Record 1986;61:229-33.

  4. ACIP. Poliomyelitis prevention. MMWR 1982;31:22-6, 31-4.

  5. ACIP. Adult immunization. MMWR 1984;33:1S-68S.

  6. McBean AM, Thoms ML, Johnson RH, et al. A comparison of the serologic responses to oral and injectable trivalent oral poliovirus vaccines. Rev Inf Dis 1984;6(supp.2):S552-5.

  7. WHO. Expanded programme on immunization. Weekly Epidemiological Record 1985;60:13-6.

  8. Committee on Immunization, American College of Physicians. Guide for adult immunization. Philadelphia, Pennsylvania: American College of Physicians, 1985.

  9. CDC. Health information for international travel, 1986. Atlanta, Georgia: US Department of Health and Human Services, Public Health Service, 1986. HHS publication no. (CDC) 86-8280.* *Available from the U.S. Government Printing Office, Washington, D.C., 20402.

Disclaimer   All MMWR HTML documents published before January 1993 are electronic conversions from ASCII text into HTML. This conversion may have resulted in character translation or format errors in the HTML version. Users should not rely on this HTML document, but are referred to the original MMWR paper copy for the official text, figures, and tables. An original paper copy of this issue can be obtained from the Superintendent of Documents, U.S. Government Printing Office (GPO), Washington, DC 20402-9371; telephone: (202) 512-1800. Contact GPO for current prices.

**Questions or messages regarding errors in formatting should be addressed to

Page converted: 08/05/98


Safer, Healthier People

Morbidity and Mortality Weekly Report
Centers for Disease Control and Prevention
1600 Clifton Rd, MailStop E-90, Atlanta, GA 30333, U.S.A


Department of Health
and Human Services

This page last reviewed 5/2/01