EPIDEMIOLOGY OF DIPTHERIA

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2. EPIDEMIOLOGY OF
DIPHTHERIA
DR. MAHESWARI JAIKUMAR.
maheswarijaikumar2103@gmail.com

3. DIPHTHERIA
• Is an acute infectious disease
caused by toxigenic strains of
Cornybacterium diphtheriae.

4. • The bacilli multiply locally,
usually in the throat, and
elaborate a powerful exotoxin
which is responsible for the
following pathology.

5. • The formation of grayish or
yellowish membrane (false
membrane) commonly over the
tonsils, pharynx, with well
defined edges and the
membrane cannot be wiped
away.

6. • Marked congestion, edema or
local tissue destruction.
• Enlargement of the regional
lymph nodes.
• Signs and symptoms of toxemia.

7. EPIDEMIOLOGICAL
DETERMINANTS

8. AGENT

11. • The causative agent, C diphtheriae
is a gram-positive, non motile
organism.
• It has no invasive power, but
produces a powerful exotoxin
which can affect the heart leading
to myocarditis.

12. • Four types of Diphtheria bacilli
are differentiated.
• gravis, mitis, belfanti and
intermedius, all pathogenic to
man.

13. SOURCE OF INFECTION
• The source of infection may be a
case or a carrier.

14. CASE
• Cases range from subclinical
infection to frank clinical cases.
• Mild or silent infections may
exhibit no more than a mere
running nose or sore throat.
These cases pose more threat in
the spread than the active cases.

15. CARRIER
• Carriers are common sources of
infection.
• Carriers may be temporary or
chronic nasal or throat carriers.

16. INFECTIVE MATERIAL
• Nasopharyngeal secretions,
discharges from skin lesions,
contaminated fomites and
possibly infected dust.

17. INFECTIVITY
• The period of infectivity may
vary from 14 to 28 days from the
onset of the disease.
• But carriers may remain infective
for much longer periods.

18. • A case or a carrier may be
considered non communicable,
when at least 2 cultures properly
obtained from nose and throat,
24 hours apart are negative for
diphtheria bacilli.

19. HOST FACTORS
• AGE : Diphtheria particularly
affects children (1-5 yrs).
• GENDER : Both genders are
affected.

20. IMMUNITY
• Infants born of immune mothers
are relatively immune during the
first few months of life.
• Children in developing countries
seem to acquire active immunity
through active infection.

21. ENVIRONMENTAL
FACTORS

22. • Case of diphtheria occur in all
seasons, although winter months
favour its spread.

23. MODE OF TRANSMISSION
• The disease is spread mainly by
droplet infection.
• It can also be transmitted
directly to susceptible persons
from infected cutaneous lesions.

24. • Transmission by objects (cups,
thermometers, toys, pencils)
contaminated by the
nasopharyngeal secretions of the
patients is possible, but only for
short periods.

25. PORTAL OF ENTRY
• RESPIRATORY ROUTE : Commonly
the portal of entry is the respiratory
tract.
• NON RESPIRATORY ROUTE : The
portal of entry sometimes may be
the skin where cuts, wounds and
ulcers not properly attended to,
may get infected with diphtheria
bacilli.(umbilical cord)

26. INCUBATION PERIOD
• 2 To 6 days.
• Occasionally longer.

27. CLINICAL FEATURE
• Respiratory tract forms of
diphtheria consists of
pharygotonsillar, larygotonsillar,
nasal and combinations thereof.

28. • Patients with pharyngotonsillar
diphtheria usually have a sore
throat, difficulty in swallowing
and low grade fever at
presentation.

29. • Examination of the throat may
show only mild erythema,
localized exudate or a
pseudomembrane.

30. PSEUDOMEMBRANE

31. • The membrane may be a
localized patch of the posterior
pharynx or tonsil, may cover the
entire tonsil, or less frequently,
may spread to cover the soft
palates and the posterior portion
of the pharynx.

34. • In the early stage the pseudo-
membrane may be whitish and
may wipe off easily.
• The membrane may extend to
become thick, blue-white to
grey-black and adherent.

35. • Attempts to remove the
membrane may result in
bleeding.
• A minimal area of mucosal
erythema surrounds the
membrane.

36. • Patients with severe disease may
have marked edema of the sub
mandibular area and the
antererior portion of the neck,
along with lymphadenopathy,
giving a characteristic “bull-
necked” appearance.

37. BULL NECK APPEARANCE

38. • Laryngeotracheal diphtheria is
most often preceded by
pharygotonsillar disease, usually
is associated with fever,
hoarseness and croupy cough at
presentation.

39. • If the infection extends into the
bronchial tree, it is the most
severe of disease.
• Initially it may be clinically
indistinguishable from viral
croup or epiglottitis.

40. • Prostration and dyspnoea soon
follow because of the
obstruction caused by the
membrane.
• This obstruction may even cause
suffocation if not promptly
relieved by intubation or
tracheostomy.

41. • The diphtheria bacilli within the
membrane continue to produce
toxin actively.

42. • This is absorbed and results in
distant toxic damage,
particularly paranchymatous
degeneration, fatty infiltration
and necrosis in heart muscle,
liver, kidneys and adrenals and
some time accompanied by gross
hemorrhage.

43. • Irregularities of the cardiac
rhythm indicate damage to the
heart.
• Later there may be difficulties
with vision, speech, swallowing,
or movement of the arms or
legs.

44. • The toxin also produces nerve
damage, resulting in paralysis of
the soft palate, eye muscles or
extremities.
• Patients who survive
complications recover
completely.

45. • Nasal diphtheria, the mildest
form of respiratory diphtheria,
usually is localized to the septum
or turbinates of one side of the
nose.
• Occasionally a membrane mat
extend into pharynx.

46. • Non respiratory mucosal surface
i.e., the conjunctivae and
genitals may also be sites of
infection.
• Cutaneous form of diphtheria is
common in tropical areas.

47. • Cutaneous diphtheria appears as
a secondary infection of a
previous skin abrasion or
infection.
• The presenting lesion, often an
ulcer, may be surrounded by
erythema and covered with a
membrane.

48. • Patients generally seek
treatment because of the
chronicity of the skin lesion.

49. CONTROL OF
DIPHTHERIA
(Cases & Controls)

50. EARLY DETECTION
• An active search for cases and
carriers should start immediately
amongst family and school
contacts.
• Carriers can be detected only by
culture method.

51. • Swabs should be taken from
both the nose and throat and
examined by culture methods for
diphtheria bacilli.
• Test should be made for the
virulence of the organism.

52. ISOLATION
• All cases, suspected cases and
carriers should be promptly
isolated, preferably in a hospital,
for at least 14 days or until
proved free of infection.

53. • At least 2 consecutive nose and
throat swabs , taken 24 hrs apart,
should be negative before
terminating isolation.

54. TREATMENT (CASES)
• When diphtheria is suspected,
diphtheria antitoxin should be given
without delay, IM or IV , in doses
ranging from 20,000 to 100,000 units or
more, depending on the severity of the
case following a test dose of 0.2ml
subcutaneously to detect sensitization
to horse serum.

55. • For mild early pharyngeal of
laryngeal disease the dose is
20,000-40,000 units.
• For moderate nasopharyngeal
disease, 40,000-60,000 units is
administered.

56. • For severe, extensive or late (3
days or more) disease, 80,000-
100,000 units.
• In addition to anti toxin every case
should be treated with penicillin or
erythromycin for 5 to 6 days to
clear the throat of C. diphtheriae
(this decreases toxin production)

57. CARRIERS
• The carriers should be treated
with 10 day course of oral
erythromycin, which is the most
effective drug for the treatment
of carriers.
• The immunity status should be
upgraded as follows.

58. CONTACTS
• Contacts merits special
attention. They should be throat
swabbed and their immunity
status determined.

59. • Non immunized close contact
should receive prophylactic
penicillin or erythromycin.
(1000-2000 units of diphtheria
antitoxin and actively immunized
against diphtheria).

60. • Contacts should be under
medical surveillance and
examined daily for evidence of
diphtheria for at least a week
after exposure.

61. COMMUNITY
• Effective control measure is by
active immunization with
diphtheria toxoid of all infants as
early in life as possible (national
immunization schedule).

62. • Subsequent booster doses every
10 years there after.
• Immunization does not prevent
the carrier state.

63. DIPHTHERIA IMMUNIZATION

64. DPT VACCINE
• It is a combined vaccine.
• The preparation of choice is DPT,
because it can be immunized
simultaneously against three
diseases, viz., Diphtheria,
pertussis, and tetanus.

66. • There are two types of vaccine :
plain and adsorbed.
• Adsorption is usually out on a
mineral carrier like aluminum
phosphate or hydroxide.

67. • Adsorption increases
immunological effectiveness
of the vaccine.
• WHO recommends the use of
adsorbed vaccines.

68. DPT STORAGE
• DPT/DT vaccine should not be
frozen.
• They should be stored in a
refrigerator between 2 to 8
degree Celsius.

69. • The vaccine should be used
before the date of expiry
indicated on the vial.
• The vaccine will lose it’s potency
if it is kept in room temperature
over a long period of time.

70. OPTIMUM AGE
• Young infants respond well to
immunization with potent
vaccines and toxoids, even in the
presence of low to moderate
levels of maternal antibodies.

71. • The Expanded programme of
Immunization has recommended
that DPT vaccine can be safely
and effectively administered as
early as 6 weeks after birth.

72. NUMBER OF DOSES
• Three doses of DPT each of
which is usually 0.5ml, should be
considered optimal for primary
immunization.

73. INTERVAL BETWEEN DOSES
• The current recommendation is
to allow an interval of 4 weeks
between 3 doses, with a booster
injection at one and a half years
or two years, followed by
another booster (DT only)at the
age of 5 to 6 years.

74. MODE OF ADMINISTRATION
• All vaccines containing mineral
carriers or adjuvants should be
injected deep intramuscular.
• This applies to DPT also.

75. • DPT is given in the upper and
outer quadrant of the gluteal
region.
• For children under one year of
age, DPT should be administered
in (lateral aspect) of the thigh.
(1984 Global Advisory Group).

76. • The most severe complications
that could follow DPT
immunization are encephalitis,
encephalopathy, prolonged
convulsions, infantile spasms
and Reye’s syndrome.

77. CONTRAINDICATIONS
• Minor conditions such as cough,
cold, mild fever are not
contraindications.
• Seriously ill children are not
vaccinated.

78. • DPT should not be repeated if a
severe reaction occurred after a
previous dose.

79. • Such reactions include collapse,
shock like state, persistent
screaming episodes,
temperature above 40 degree
Celsius, convulsions and other
neurological symptoms.

80. • DT only is recommended in such
case. (2 doses with 4 weeks
apart with a booster dose 6
months to one year).
• Children who have received DPT
earlier, should receive only DT as
booster at 5-6 years or at school
entry.

82. ANTISERA
Diphtheria
antitoxin prepared
in horse serum is
still the mainstay
of passive
prophylaxis and
also for treatment
of diphtheria.

84. THANK YOU