Chicken pox, also known as varicella, is an acute, highly infectious disease caused by the varicella-zoster virus. It is characterized by a vesicular rash that may be accompanied by fever and malaise. The virus is usually spread through respiratory droplets from infected individuals. While chicken pox infections usually cause a mild, self-limiting disease in children, it can lead to more severe complications in adults and pregnant women. Recovery results in lifelong immunity against future chicken pox infections.

1. VARICELLA
CHICKEN POX
Vd Rakesh Shukla
Lecturer,
Dept of Swasthavritta
GAAC, Ahmedabad Vd Rakesh Shukla, Lecturer, GAAC,
Ahmedabad

2. • Chicken pox or varicella is an acute, highly infectious
disease caused by varicella-zoster (V-Z) virus.
• It is characterized by vesicular rash that may be
accompanied by fever and malaise. Chicken pox and
herpes are now regarded as different host response to
the same aetiological agent.
Vd Rakesh Shukla, Lecturer, GAAC,
Ahmedabad

3. Epidemiological determinants
1.Agent factors: V-Z virus is also called as “human (alpha)
herpes virus.
2) Source of infection: usually a case of chicken pox. The
virus occurs in the oropharyngeal secretions and lesion of
the skin and mucosa. Rarely the source of infection may
be herpes zoster. The virus can be readily isolated from
the vesicular fluid during the 1st , 3 days of illness. The
scabs however are not infected
Vd Rakesh Shukla, Lecturer, GAAC,
Ahmedabad

4. 3) Infectivity: estimated to be 1-2 days before the
appearance of the rash, and 4-5 days there after. The
virus tends to die out before the pustular stage.
4) Secondary attack rate – highly communicable, 90%
secondary attack rate .
Vd Rakesh Shukla, Lecturer, GAAC,
Ahmedabad

5. Recovery from primary infection is commonly
followed by the establishment of latent
infection in the cranial nerves sensory
ganglia and spinal dorsal root ganglia, often
for decades, with out clinical manifestations.
It is a painful, vesicular, pustular eruptions in
the distribution of 1 or more sensory nerve
roots. This virus can be grown in tissue
culture.
Vd Rakesh Shukla, Lecturer, GAAC,
Ahmedabad

6. Host factors
1) Age: among children under age of 10 years.
2) Immunity: one attack gives durable immunity; second
attacks are rare. maternal antibody protects the infant
during the 1st few months of life. The IgG antibodies
persists for life and their presence is correlated with the
protection against varicella.
3) Pregnancy: infection during pregnancy presents a risk
for the foetus and neonate.
Vd Rakesh Shukla, Lecturer, GAAC,
Ahmedabad

7. 5) Environmental factors:
Chicken pox shows a seasonal trend in India, the
disease occurring mostly during the 1st 6 months of the
year. Over crowding favors its transmission
6) Transmission: person to person by droplet infection
and droplet nuclei. Most of them are infected by face to
face (personal contact).
7) The portal of entry of the virus is the respiratory tract.
The virus can cross the placental barrier and infect the
foetus, a condition known as congenital varicella.
Vd Rakesh Shukla, Lecturer, GAAC,
Ahmedabad

8. 8) Incubation period: 14-16 days, although extremes as
wide as 10-21 days.
9) Clinical features: may vary form mild illness with only a
few scattered lesions to a severe febrile illness with wide
spread rash. In majority of cases the disease tend to be
mild and typical
Vd Rakesh Shukla, Lecturer, GAAC,
Ahmedabad

9. 2 stages
I) Pre- eruptive stage:
onset is sudden with mild or moderate fever, pain in
back, shivering and malaise lasting for 24 hours. In adults,
the prodromal illness is usually more severe and may last
for 2-3 days.
Vd Rakesh Shukla, Lecturer, GAAC,
Ahmedabad

10. II) Eruptive stage:
In children rash is often the 1st sign. It comes on the day
the fever starts. The distinctive features are
a) Distribution: rash is symmetrical . 1st appears on the trunk
where it is abundant, then face, arms and legs where it is
less abundant. Mucosal surface are generally involved. The
density of the eruption diminishes centrifugally.
b) Rapid evolution: rash advances quickly through the stages
of macule, papule, vesicle, scab. dew drops on skin is the 1st
appearance. Scabbing begins 4-7 days after the rash
appears.
Vd Rakesh Shukla, Lecturer, GAAC,
Ahmedabad

11. c) Pleomorphism: that is all stages of the rash (papules,
vesicles and crusts may be seen simultaneously at 1 time
at the same area.
d) fever: the fever does not run high but shows exacerbations
with each fresh crop of eruption.
Complications
Hemorrhages, pneumonia, encephalitis, acute cerebellar
ataxia, reye’s syndrome, cutaneous scars, atrophies limbs,
microcephaly, LBW, micropthalmia, chorioretinitis,
deafness, cerebro- cortical atrophy
Vd Rakesh Shukla, Lecturer, GAAC,
Ahmedabad

12. Laboratory diagnosis:
• Not required where clinical signs are usually clear cut.
• Examination of the vesicle fluid under electron microscope – shows
round particles(brick shaped in small pox)
Control: –
• Notifications
• Isolations of cases for about 6 days after the onset of rash and
disinfection of articles soiled by nose and throat discharges.
• Prevention – Varicella Zoster Immunoglobin (VZIG) – given with in
72 hours of exposure. IM dose 12.5 units/kg body weight upto max
of 625 units with a repeat dose in 3 weeks.
• Vaccine – a live attenuated varicella virus vaccine is safe for
children between 12-18 months.
Vd Rakesh Shukla, Lecturer, GAAC,
Ahmedabad

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Vd Rakesh Shukla, Lecturer, GAAC,
Ahmedabad