COMMUNICABLE DISEASE MANUAL POLICIES / PROCEDURES
DIPHTHERIA
OBJECTIVE:
Control and management of a diphtheria outbreak. A diphtheria outbreak exists
in a community whenever there is another case besides the primary or index
case.
DESCRIPTION:
Corynebacterium diphtheria usually occurs as membranous nasopharyngitis
and/or obstructive laryngotracheitis. Less commonly the disease presents as
cutaneous, vaginal, conjunctival, or otic infections. Cutaneous diphtheria is more
common in tropical areas and among the homeless. Serious complications
include upper airway obstruction caused by extensive membrane formation, toxic
myocarditis and peripheral neuropathies. Humans are the only known reservoir
of C diphtheria, which is present in discharges from the nose, throat, eyes and
skin lesions for 2-6 weeks after infection. Patients treated with an appropriate
antimicrobial agent usually are communicable for fewer than four (4) days.
Transmission results from intimate contact with a patient or carrier; rarely fomites
and foodborne sources serve as vehicles of transmission. Although infection
can occur in people who are immunized, or partially immunized, disease is most
common and most severe in people who are not immunized or inadequately
immunized. The incidence of respiratory diphtheria is greatest during autumn
and winter, but summer epidemics occur in warm, moist climates in which skin
infections are prevalent. The incubation period is usually 2 to 7 days, with a
range of 1 to 10 days (see Diphtheria Time Line attached).
EQUIPMENT:
MDSS User Manual and disease specific form found in MDSS. Contact Sheet
and MDCH Notification of Serious Communicable Disease Fax sheet. MDCH
website
at
www.michigan.gov/cdinfo,
CDC
website
at
www.cdc.gov/diseasesconditions/az,
VPD
Guidelines
at
www.michigan.gov/immunize.
POLICY:
Legal Responsibility: Michigan's communicable disease rules of Act No. 368 of the
Public Acts of 1978, as amended, being 333.5111 of the Michigan Compiled Laws.
Follow-up time; 24 hours post referral and notify MDCH immediately via fax
of confirmed or probable case. IT ALSO NEEDS TO BE ENTERED INTO
MDSS WITHIN 24 HOURS OF RECEIPT OF REFERRAL.
PROCEDURE:
A.
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Case Investigation
1.
Referral received per phone call, laboratory results, or automatically
through MDSS.
2.
Document all case investigation proceedings.
3.
Contact MD and/or client to start process of completing disease
specific form in MDSS, and Diphtheria Close Contact Sheet.
4.
Immediately notify the CD Supervisor and Medical Director,
for confirmed or suspected cases. Call MDCH at 517-3358165 and Regional Epidemiologist. Nurse to Fax Notification
of Serious Communicable Disease Form to MDCH for
confirmed or suspected cases and notify MDCH
Immunization Division Vaccine-Preventable Disease (VPD)
Surveillance Coordinator at 517-335-8159.
5.
B.
If outbreak, or one (1) probable or confirmed case, notify CD
Supervisor who will then report to Medical Director and State
Health Department as necessary.
Case Classification
Clinical Case Definition: An upper-respiratory tract illness characterized
by sore throat, low-grade fever, and an adherent membrane of the
tonsil(s), pharynx, and/or nose.
Case Classification:

Probable: A clinically compatible case that is not laboratory
confirmed and is not epidemiologically-linked to a laboratoryconfirmed case.

Confirmed: A clinically compatible case that is either laboratory
confirmed or epidemiologically-linked to a laboratory-confirmed
case.
Comment: Respiratory disease caused by nontoxigenic Corynebacterium
diphtheriae should be reported as diphtheria. Cutaneous diphtheria
should not be reported. All diphtheria isolates, regardless of association
with disease, should be sent to the Diphtheria Laboratory National Center
for Infectious Diseases, CDC. Arrangements should be made through
the MDCH laboratory.
Note: On rare occasions, respiratory diphtheria may result from infection
with
other
Corynebacterium
species
(C.
ulcerans
or
C.
pseudotuberculosis). These isolates should also be forwarded to the
CDC.
C.
Lab Criteria for Diagnosis.
1.
MDCH accepts only isolation of Corynebacterium diphtheriae
from a clinical specimen from a culture and PCR, or
2.
Histopathologic diagnosis of diphtheria.
3.
Guidelines for Collection of Specimens for Isolation of C.
diphtheriae (source: World Health Organization [WHO]).
Throat Swabs
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
Pharynx should be clearly visible and well illuminated.

Depress tongue with an applicator and swab the throat without
touching the tongue or inside of the cheek.

Rub vigorously over any membrane, white spots, or inflamed
areas; slight pressure with a rotating movement must be applied
to the swab.

If any membrane is present, lift the edge and swab beneath it to
reach the deeply embedded organisms.
Nasopharyngeal Specimens

Insert the swab into the nose through one nostril beyond the
anterior nares.

Gently introduce the swab along the floor of the nasal cavity,
under the middle turbinate until the pharyngeal wall is reached.
Force must not be used to overcome any obstruction.
Skin Diphtheria and Other Lesions
D.
E.

Lesions should be cleansed with sterile normal saline and crusted
material removed.

Press the swab firmly into the lesion.
4.
Diphtheria testing may not be available in most clinical
laboratories. Contact MDCH Microbiology Laboratory (517-3358067) and MDCH VPD Surveillance Coordinator (517-335-8159)
for further direction.
Immunity/Susceptibility
1.
Lifelong immunity is usually, but not always acquired after disease
or inapparent infection.
2.
Immunization with toxoid produces prolonged, but not lifelong,
immunity.
3.
Serosurveys in the U.S. indicate that 40 percent of adults lack
protective levels of circulating antitoxin.
4.
Antitoxin immunity protects against systemic disease, but not
colonization in the nasopharynx.
Control Measures
1.
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Patient related measures:

Reports of suspect diphtheria should be investigated
immediately.

Suspect cases should be reported promptly by telephone
to MDCH VPD Surveillance Coordinator so that
arrangements can be made to obtain diphtheria antitoxin
for the patient from CDC and the MDCH Laboratory can be
notified to set up for cultures.
Contact information:
MDCH VPD Surveillance Coordinator
517-335-8159
MDCH Communicable Disease Epidemiology Office
517-335-8165
CDC Consultation (National Immunization Program)
404-639-8257
CDC after-hours: 770-488-7100 or 404-639-2888 or
404-639-2889
MDCH Laboratory: 517-335-8067
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
The patient should be placed in strict isolation, which
should be maintained until elimination of the organism is
demonstrated by negative cultures of two samples
obtained at least 24 hours apart after completion of
antimicrobial therapy.

Obtain both nasal and pharyngeal swabs for culture, if this
has not yet been done, to confirm the diagnosis. Ideally
these should be collected prior to initiation of antibiotic
treatment.

Obtain serum for serology studies of antibodies to
diphtheria toxin.

Obtain, if possible, a consultation from an Infectious
Disease physician on the patient; consider treatment with
diphtheria antitoxin in consultation with MDCH and CDC
authorities.

Begin/assure antimicrobial therapy (antimicrobial therapy
is not a substitute for antitoxin treatment). Antimicrobial
therapy is recommended until patient can swallow
comfortably.

Administer/assure active immunization with diphtheria
toxoid during convalescence, because clinical diphtheria
does not necessarily confer immunity.

Obtain repeat nasal and pharyngeal specimens for culture
a minimum of two (2) weeks after completion of
antimicrobial treatment to assure eradication of the
organism.

Persons who continue to harbor the organism after
treatment with either penicillin or erythromycin should
receive an additional 10-day course of oral erythromycin
and should submit samples for follow-up cultures.
2.
Contact Management:

Management is based on individual circumstances,
including immunization status and the likelihood of
surveillance and adherence to prophylaxis.

Identify close contacts:

Household members

Persons with a history of direct contact with a casepatient (e.g., caretakers, relatives, or friends who
regularly visit the home);

Medical staff exposed to case-patient’s oral or
respiratory secretions.

Assess and monitor contacts for signs and symptoms for
diphtheria for at least seven (7) days.

Obtain nasal and pharyngeal swab specimens from all
contacts for C. diphtheriae cultures irrespective of their
immunization status.

Administer/assure antimicrobial prophylaxis for contacts.
Use the Diphtheria Close Contact Sheet for recording
contacts and their antibiotic prophylaxis. Recommended
prophylaxis:



A single dose of intramuscular benzathine penicillin
G (600,000 units for persons < six (6) years of age
and 1.2 million units for persons > six (6) years of
age). OR

A 7- to 10-day course of oral erythromycin (40
mg/[kg/d]) for children and 1 g/d for adults.
Contacts who cannot be kept under surveillance should
receive:

Benzathine penicillin G, but not erythromycin for
reasons of compliance.

An initial dose of DTaP, Tdap, DT or Td, depending
on age and the person’s immunization history.

Cultures done before and after prophylaxis.
Assess diphtheria toxoid (DPT, DTaP, Tdap, DT, or Td)
vaccination history status of Asymptomatic contacts:

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If < three (3) doses: Administer immediate dose of
diphtheria toxoid and complete primary series
according to schedule.
F.
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
If > three (3) doses with last dose > five (5) years
ago:
Administer immediate booster dose of
diphtheria toxoid.

If > three (3) doses with last dose < five (5) years
ago: Children in need of their fourth primary dose.

Adult contacts whose occupations involve handling food,
especially raw milk, or close association with nonimmunized children, should be excluded from work until
bacteriologic exam proves them not to be carriers.

Active immunization against diphtheria should be
undertaken during convalescence from diphtheria in every
patient because this exotoxin - mediated disease does not
necessarily confer immunity.

Upon orders of Supervisor and/or Medical Director, the
following should be done:

Record search of preschool, day care center and
school to determine who has not had adequate
doses of DPT/DT/Td for age.

EXCLUDE FROM SCHOOL all students not
vaccinated adequately. May re-enter school if
proof provided of adequate vaccination. If they are
not vaccinated (per waiver or non-compliance), wait
until 14 days after date of onset of last reported
case.

Health Department to provide clinic for all students
who need vaccination.

Educate contacts regarding period of communicability,
incubation period, spread and treatment. An excellent
Question and Answer Diphtheria Information Sheet from
the Immunization Action Coalition is located with your Fact
Sheets in this policy.

In the event of death, obtain and send copies of
hospital discharge summary, death certificate, and
autopsy report to MDCH Immunization Division.
MDSS Case Reporting:
1.
Complete case investigation using disease specific form in MDSS.
2.
Notify CD Supervisor that the case report is ready for review.
PHN will be notified if corrections are needed prior to closing case
in MDSS.
3.
REFERENCES:
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CD Supervisor reviews case for completeness and closes MDSS
case report.
Current Epidemiology and Prevention of Vaccine-Preventable Diseases (pink
book)
Current Red Book
Current Control of Communicable Diseases Manual
Current disease specific “Fact Sheet”
Websites: www.cdc.gov/diseasesconditions/az/a.html
www.michigan.gov/cdinfo
www.michigan.gov/immunize (VPD Guidelines)