Epidemiologic Notes and Reports
Transmission of Pertussis from Adult to Infant --
Michigan, 1993
During 1993, a total of 6586 pertussis cases was reported in
the United States, including 675 (10%) cases among persons aged
greater than 19 years. However, the total number of cases probably
was substantially higher because only an estimated 10% of all
pertussis cases are reported (1); underreporting is greater among
adults, who often have only a mild cough. This report summarizes
the investigation of two cases of pertussis in which transmission
occurred from an adult resident of Massachusetts who was visiting
the residence of an infant in Michigan.
Patient 1. On October 11, 1993, a 4-month-old boy in Ann
Arbor, Michigan, developed a mild cough. His symptoms gradually
worsened during the following 2 weeks with paroxysms of cough
associated with whooping, vomiting, and apnea. A culture of a
nasopharyngeal specimen obtained on October 25 yielded Bordetella
pertussis. On September 8, the infant had received one dose of
diphtheria and tetanus toxoids and pertussis vaccine (DTP).
Treatment for the infant and chemoprophylaxis of his household
contacts with erythromycin were initiated on October 27 and
continued for 2 weeks. Although hospitalization was not required,
the infant had a persistent cough for 3 months. The infant had not
attended group day care.
Patient 2. During September 17-20, 1993, the infant's
47-year-old aunt from Cambridge, Massachusetts, had visited his
home. During the visit, she developed a mild cough. On return to
Massachusetts, her cough worsened, and she developed paroxysms of
cough with inspiratory whoop and posttussive apnea. On September
23, bronchitis was diagnosed, and she was treated with codeine. On
September 29, therapy with a 7-day course of erythromycin and a
steroid inhalant was initiated. Because of the history of close
contact with her nephew -- in whom a culture-confirmed case of
pertussis had been diagnosed -- on November 17, a serum sample was
obtained for immunoglobulin G (IgG) antibody to pertussis toxin;
the serum IgG concentration was greater than 30 ug/mL * . Inhalant
therapy was discontinued, and a 14-day course of erythromycin was
prescribed for the patient and three household contacts.
Reported by: ED Mokotoff, MPH, Disease Surveillance Section, RA
Dunn, MD, Immunization Section, DR Johnson, MD, Disease Control
Div, KR Wilcox, Jr, MD, State Epidemiologist, Michigan Dept of
Public Health. L Burger, MPH, S Lett, MD, Immunization Program,
Massachusetts Dept of Public Health. Div of Epidemiology and
Surveillance, National Immunization Program, CDC.
Editorial Note
Editorial Note: The investigation of the two cases described in
this report indicates the continuing occurrence of pertussis in
adults and that adults can be a source of pertussis infection for
susceptible infants. Health-care providers should consider
pertussis in the differential diagnoses for acute cough of greater
than or equal to 7 days' duration in adults, particularly if the
cough is paroxysmal and associated with posttussive vomiting and/or
whooping. Although the cough associated with pertussis in adults
generally is mild (3), the case in this report indicates that
classic symptoms of pertussis (e.g., paroxysms of cough,
posttussive whoop, and apnea) can occur in adults.
Laboratory confirmation of pertussis can be difficult because
of the low sensitivity of microbiologic cultures and the occurrence
of false results from direct fluorescent antibody tests.
Serodiagnosis and recently developed polymerase chain reaction
tests may be useful for diagnosis, particularly in persons with a
mild cough. However, these tests have not been standardized and are
not widely available.
Transmission of pertussis can be reduced with prompt diagnosis
and treatment of cases and early administration of chemoprophylaxis
to close contacts (4). Administration of erythromycin for 14 days
is recommended for persons with pertussis and all their household
contacts (regardless of age or vaccination status) and is an
important method of protecting children aged less than 6 months who
are too young to have received the initial three-dose series of DTP
recommended during infancy (5,6). Chemoprophylaxis of household
contacts with erythromycin should be administered as soon as
possible after first contact with a primary case; chemoprophylaxis
administered greater than or equal to 21 days after first contact
is considered of limited value (7).
References
Sutter RW, Cochi SL. Pertussis hospitalization and mortality in
the United States, 1985-1988. JAMA 1992;267:386-91.
Marchant CD, Loughlin AM, Lett SM, et al. Pertussis in
Massachusetts, 1981-1991: incidence, serologic diagnosis, and
vaccine effectiveness. J Infect Dis 1994;169:1297-305.
Bass JW. Pertussis: current status of prevention and treatment.
Pediatr Infect Dis 1985;4:614-9.
Sprauer MA, Cochi SL, Zell ER, et al. Prevention of secondary
transmission of pertussis in households with early use of
erythromycin. Am J Dis Child 1992;146:177-81.
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).
American Academy of Pediatrics. Pertussis. In: Peter G, ed. 1994
Red book: report of the Committee on Infectious Diseases. 23rd ed.
Elk Grove Village, Illinois: American Academy of Pediatrics,
1994:355-67.
Health and Welfare Canada. Pertussis consensus conference. In:
Canada communicable disease report. Vol 19-16. Ottawa: Health and
Welfare Canada, 1993:124-35.
Since 1987, the Massachusetts Public Health Biologic Laboratory
has performed an indirect enzyme-linked immunosorbent assay for IgG
to pertussis toxin for diagnosis of pertussis among persons aged
greater than or equal to 11 years. A serum antipertussis toxin
concentration of greater than or equal to 20 ug/mL in one specimen
is considered by public health authorities in Massachusetts as
evidence of recent infection with B. pertussis (2).
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