Diphtheria Acquired by U.S. Citizens in the Russian Federation and Ukraine -- 1994
Epidemic diphtheria has reemerged in 14 of the 15 New
Independent States (NIS) of the former Soviet Union (1); during
1994, a provisional total of 47,802 cases and 1746 deaths from
diphtheria were reported throughout the NIS. This report describes
one confirmed and one probable case of diphtheria acquired in
countries where the disease is epidemic (Russian Federation and
Ukraine) by U.S. citizens during November and December 1994.
Patient 1. A 42-year-old woman, born in Russia but living in
the United States for several years, arrived in Moscow on November
22. She had onset of fever and sore throat on December 6 and was
hospitalized on December 7 with a provisional diagnosis of
diphtheria. Her vaccination history was unknown, and she was not
aware of contact with diphtheria patients or carriers. She was
treated with 9000 international units (IU) of equine diphtheria
antitoxin, antibiotics, and prednisone. On December 8, she was
transferred to a referral hospital in Helsinki; findings on
examination included a pharyngeal membrane. Treatment included
administration of 40,000 IU of antitoxin, penicillin G (for 6
days), and several days of roxithromycin. Toxigenic C. diphtheriae,
biotype gravis, was isolated from a pharyngeal culture obtained
December 9. Follow-up cultures on December 12 and 15 were negative.
Her antitoxin level was measured in Helsinki by Vero cell
neutralization assay and was greater than 5 IU/mL; however, the
level measured by an enzyme immunoassay that is specific for human
antibodies was less than 0.03 IU/mL, indicating that the Vero cell
assay was detecting recently administered equine antitoxin. She
recovered fully without complications.
Patient 2. On November 28, a 22-year-old woman from New Jersey
working in Kherson in southern Ukraine since June 1994 had onset of
a sore throat; she was hospitalized on November 29 with a
provisional diagnosis of diphtheria. She had received five doses of
diphtheria and tetanus toxoids and pertussis vaccine (DTP) during
childhood and an adult formulation tetanus and diphtheria toxoids
(Td) booster in August 1991. She had no recognized contact with a
known diphtheria patient or carrier. Findings on examination
included a tonsillar and posterior pharyngeal membrane. The patient
had treated herself with ciprofloxacin for 1 day and had had at
least one dose of oral penicillin before a throat culture was
obtained (the culture was negative). Treatment comprised 80,000 IU
of diphtheria antitoxin and a course of parenteral penicillin. A
diphtheria antitoxin level of 0.2 IU/mL by Vero cell neutralization
assay was detected in both a blood specimen obtained at the time of
her arrival in Ukraine in June 1994 and a convalescent sample. She
recovered fully without complications.
Reported by: J Vuopio-Varkila, MD, R-M Olander, MSc, National
Public Health Institute; V Valtonen, MD, Helsinki Univ Central
Hospital, Helsinki, Finland. R Crooks, MD, C Stewart, Office of
Medical Svcs, Peace Corps, Washington, DC. Childhood and
Respiratory Diseases Br, Div of Bacterial and Mycotic Diseases,
National Center for Infectious Diseases; Child Vaccine Preventable
Diseases Br, Div of Epidemiology and Surveillance, National
Immunization Program, CDC.
Editorial Note
Editorial Note: Diphtheria is a potentially severe illness; among
persons who are unvaccinated, the case-fatality rate ranges from 5%
to 10%. The disease is rare in the United States: since 1980, five
or fewer cases have been reported each year, and since 1988, all
reported culture-confirmed cases have been imported. However, based
on serologic studies, 20%-60% of U.S. adults aged greater than 20
years are susceptible to diphtheria (2,3). The two cases described
in this report are the first known to have occurred among U.S.
citizens from exposure during the current epidemic in the NIS and
emphasize the risk for persons who travel to countries with
epidemic diphtheria. In addition, these cases suggest the potential
for importation of toxigenic strains of C. diphtheriae to the
United States by persons who arrive from affected areas. Although
importation of diphtheria from the NIS to the United States has not
been reported, at least 20 imported cases related to this epidemic
have been reported in European countries (4-6).
The diagnosis of diphtheria was confirmed by culture in the
first case in this report. Although diphtheria was not
laboratory-confirmed in the second patient, the clinical diagnosis
was made by physicians experienced in diagnosing and treating
diphtheria, and the CDC case definition for a probable case was met
(7). Her negative throat culture does not exclude the diagnosis
because she had begun antibiotic therapy before the culture
specimen was taken. In addition, levels of antitoxin greater than
or equal to 0.1 IU, as those present in this patient, are
considered to confer a relative degree of protection against
disease (8); although no level of antitoxin provides absolute
protection (8), this patient appeared to have relatively mild
disease and did not develop toxic complications. Because clinical
diphtheria may not induce protective immunity, the lack of an
increase in postdisease antitoxin level would not exclude the
diagnosis; booster vaccination with an age-appropriate diphtheria
toxoid-containing vaccine is recommended during convalescence (8).
To minimize the risk for diphtheria, all U.S. residents should
be up-to-date for diphtheria vaccination, regardless of whether
they plan international travel. The Advisory Committee on
Immunization Practices recommends that all children receive a
routine series of five doses of DTP (or diphtheria and tetanus
toxoids for pediatric use {DT} if pertussis vaccine is
contraindicated) with doses at ages 2, 4, 6, and 12-15 months, and
4-6 years; Td boosters should be given at age 11-16 years, and
every 10 years thereafter (9,10). For persons aged greater than or
equal to 7 years who have not been previously vaccinated against
diphtheria, the primary series consists of three doses of Td, with
intervals of 1-2 months between the first two doses and 6-12 months
between the second and third doses; Td boosters should be given
every 10 years thereafter. To improve diphtheria-specific levels of
immunity within the population, active vaccination against tetanus
given as part of wound management should involve use of a vaccine
containing both diphtheria and tetanus toxoids rather than single
antigen tetanus toxoid (i.e., DTP {or DT if pertussis vaccine is
contraindicated} for children aged less than 7 years and Td for
persons aged greater than or equal to 7 years). Travelers to areas
with endemic diphtheria or outbreaks should consult their medical
providers to ensure they are adequately vaccinated. Travelers
should have completed a primary series of at least three doses of
diphtheria toxoid and should have received the most recent dose of
vaccine (either primary series or booster) within the previous 10
years. In addition, travelers to affected countries should be
advised to contact a health-care provider promptly if they develop
a sore throat during either travel or the 2-week period after
return from travel.
References
CDC. Diphtheria epidemic -- New Independent States of the
former
Soviet Union, 1990-1994. MMWR 1995;44:177-81.
Crossley K, Irvine P, Warren JB, Lee BK, Mead K. Tetanus and
diphtheria immunity in urban Minnesota adults. JAMA 1979;242:2298-
3000.
Koblin BA, Townsend TR. Immunity to diphtheria and tetanus in
inner-city women of child-bearing age. Am J Public Health
1989;79:1297-8.
Lumio J, Jahkola M, Vuento R, Haikala O, Eskola J. Diphtheria
after a visit to Russia. Lancet 1993;342:53-4.
Expanded Program on Immunization, World Health Organization.
Recrudescence of diphtheria -- Poland. Wkly Epidemiol Rec
1993;68:261-4.
De Zoysa A, Efstratiou A, George RC, Vuopio-Varkila J, Jahkola
M, Rikushin Y. Diphtheria and travel {Letter}. Lancet 1993;342:446.
CDC. Case definitions for public health surveillance. MMWR
1990;39(no. RR-13):11.
Dixon JMS. Diphtheria. In: Topley WWC, Parker MT, Collier L,
Wilson G, eds. Topley and Wilson's principles of bacteriology,
virology, and immunity. Philadelphia: BC Decker, 1990:56-75.
ACIP. Diphtheria, tetanus, and pertussis: recommendations for
vaccine use and other preventive measures -- recommendations of the
Immunization Practices Advisory Committee (ACIP). MMWR 1991;40(no.
RR-10).
CDC. Recommended childhood immunization schedule -- United
States, January 1995. MMWR 1995;43:959-60.
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