Lecture - Chicken Pox

Chicken pox
(varicella)
Herpes zoster
Smallpox (Variola)
1
Session objectives
1 Signs and symptoms & complications
2 Diagnosis
Epidemiology(Infectious agent, occurrence, 3
Reservoir, Mode of transmission, incubation
period, Susceptibility & resistance)
4 Prevention & Control
5 Treatment
2
• Acute generalized viral disease
Sudden onset of slight fever, mild
constitutional symptoms &skin eruption
Maculo-papular few hours vesicles…. 3-4days
and leaves granular scabs. The vesicles are
uni-locular and collapse on puncture.
Lesions commonly occur in successive
crops with several stage of maturity present
at the same time
3
Chicken Pox - Typical Early Lesion
4 Chicken Pox - Evolving Lesions

Chicken Pox - Close-Up of Day 6
5
More abundant on covered than exposed parts of
the body
Lesions may appear high in the axilla &on the
scalp, mm of the mouth &R.T &on the
conjunctivae
They may be so few as to escape attention
Mild &atypical infection & inapparent can occur
Serious complications; pneumonia, secondary
bacterial infections, hemorrhagic complications
and encephalitis.
7
Sever form can occur in adults,
Children with acute leukemia are at high risk of severe

disseminated form with CFR of 5-10 %
Neonates (5-10days) liable to severe generalized form

and have a CFR of up to 30% but with antiviral drugs the
rate likely to be lower.
Infection early in pregnancy may be associated with

(CVS) in 0.7 % & if infection occurs at 13-20 weeks it
may be associated with CVS in 2%.
8
congenital varicella syndrome (CVS)
 Damage to brain: encephalitis, microcephaly,
hydrocephaly, aplasia of brain

 Damage to the eye: optic stalk, optic cup, and lens
vesicles, microphthalmia, cataracts, chorioretinitis,

optic atrophy
 Other neurological disorder: damage to cervical and
lumbosacral spinal cord, motor/sensory deficits,

absent deep tendon reflexes, anisocoria/
Horner's syndrome
 Damage to body: hypoplasia of upper/lower
extremities, anal and bladder sphincter dysfunction

 Skin disorders: (cicatricial) skin lesions,
hypopigmentation
9
Herpes zoster (shingles) is a local manifestation or
reactivation of varicella infection in dorsal root ganglia.
Characterized by vesicles with an erythematous base in
irregular crops along nerve pathways. Severe pain &
paraesthesia for at least several weeks in 15 % of
patients, and may result in permanent nerve damage, or
post herpetic neuralgia. The incidence of disease
increase with age (mainly in 15% of adults but may be
seen in debilitated children).
10
The diagnosis of varicella is primarily clinical.
• Vesicular fluid can be examined with a Tsanck
smear, or better with examination for
direct fluorescent antibody. The fluid can also be
"cultured
• Prenatal diagnosis of fetal varicella infection can
be performed using ultrasound, PCR (DNA) test
of the mother's amniotic fluid,
11
:Infectious agent
Human (alpha) herpes virus 3
.a member of Herpes virus group ,)V-Z virus(
:Occurrence
World wide, in temperate climates at least 90% of the
population has had chicken pox by the age of 15 years,
occurs most frequently in winter &spring.
In tropical countries higher proportion of cases
occurring among adults.
Zoster occurs more commonly in older groups
Reservoir : Humans
12
;Mode of transmission: person-to –person by
1. Direct contact
2. Droplet
3. airborne spread
4. articles soiled
of vesicle fl. or secretion of the RT of chicken pox case or vesicle
fluid of patient with HZ
 Scabs of varicella lesions are not infectious.
 Chickenpox is one of the most readily communicable diseases.
 HZ has a lower rate of transmission, but contacts of HZ may
develop chickenpox.
13
Incubation period: 2-3 weeks , commonly
14-16 days
Period of communicability
Rash
1-2 days 5 days
before after and 7 days
for HZ
14
:Susceptibility & resistance
chicken pox is universal among those not
previously infected
More sever form occur among adults
Infection usually confers life long immunity
Second attacks are rare
sub clinical re-infection is common
Viral infection remain latent &disease may
occur later as HZ in about 15% of older adults
&some times in children
15
:Prevention
1. Live attenuated Varicella vaccine (Varivax). A single
dose of 0.5 ml sc is recommended for children age
12m-12 yrs .who have not had chicken pox . This
vaccine had cumulative efficacy at 70-90 % followed
for up to 6 years in preventing varicella in children. It
is protective if it is given within 3 days of exposure.
?Who should get chickenpox vaccine and when
Some people should not get chickenpox vaccine or
.should wait
16
?Who should get chickenpox vaccine and when
Routine
Children who have never had chickenpox should get 2
:doses of chickenpox vaccine at these ages
1st Dose: 12-15 months of age
,2nd Dose: 4-6 years of age (may be given earlier
)if at least 3 months after the 1st dose
People 13 years of age and older (who have never had
chickenpox or received chickenpox vaccine) should get
.two doses at least 28 days apart
17
Some people should not get chickenpox vaccine or
should wait.
• People have ever had a life-threatening allergic reaction
to a previous dose of chickenpox vaccine or gelatin or
the antibiotic neomycin.
• People who are moderately or severely ill at the time the
shot is scheduled should usually wait until they recover
before getting chickenpox vaccine.
• Pregnant women should wait to get chickenpox vaccine
until after they have given birth. Women should not get
pregnant for 1 month after getting chickenpox vaccine
2. Protect high risk individuals from
exposure by
immunizing household and close
contacts. .
3. VZIG is effective in preventing or
modifying the disease .if given within 96
hours of exposure
19
: Control
1. Reporting is not necessary
2. Isolation :Exclude children from school for 5 days
after appearance of rash
3. Disinfection of articles soiled by discharge from
nose & throat
4. Protection of contact:
 VZIG given within 96 hrs of exposure
 Varivax vaccine given within 3 days of exp.
 Newborns of mothers exposed who develops
varicella 5 days before or 2 days after delivery
(VZIG).
20
 VZIG given to pregnant does not prevent
CVS
 Acyclovir (antiviral drugs) if given
within week of exposure
5. Treatment: symptomatic and antiviral
drugs like Vidarabine, Zovirax (Acyclovir),
if taken within 24 hours of rash onset, a
dose of 80 mg/kg/day in 4 divided doses for
5 days.
21
THANK YOU
22

Lecture - Chicken Pox

Uploaded by

Copyright:

Available Formats

Lecture - Chicken Pox

Uploaded by

Document Information

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

Lecture - Chicken Pox

Uploaded by

Copyright:

Available Formats

Chicken pox

4 Chicken Pox - Evolving Lesions

Children with acute leukemia are at high risk of severe

Neonates (5-10days) liable to severe generalized form

Infection early in pregnancy may be associated with

hydrocephaly, aplasia of brain

vesicles, microphthalmia, cataracts, chorioretinitis,

lumbosacral spinal cord, motor/sensory deficits,

extremities, anal and bladder sphincter dysfunction

You might also like