this ppt contains all information about epidemiology of chickenpox. It is useful for students of medical field learning preventive and social medicine, Swasthavritta (Ayurved) and everyone who is interested in it

1. Chickenpox ( Varicella)
Dr. Shubhangi Kshirsagar
Assistant professor
Department of Swasthavritta & Yoga

2. Chickenpox
Chickenpox 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

3. Agent factors
a. Agent - V-Z virus (Human (alpha) herpes virus 3
b. Source of infection – case of Chickenpox
c. Infectivity –
1 to 2 days before the appearance of rash
4 to 5 days after rash
a. Secondary attack rate - in household contacts
approaches 90 per cent

4. Host factors
a. Age – under 10 years
b. Immunity - one attack gives durable immunity,
second attacks are rare.
c. Pregnancy –
Infection during pregnancy presents a risk for
the foetus leading to congenital varicella
syndrome.
Infants, whose mothers had chickenpox
during pregnancy, have a higher risk of
developing herpes zoster in the first years of life.

5. Environmental factors
Winter and spring

6. Mode of transmission
Person to person by droplet infection and by
droplet nuclei.
Most patients are infected by "face-to-face"
(personal) contact.
The portal of entry - the upper respiratory
tract or the conjunctiva.
Incubation period – 14-16 days

7. Clinical features
1. Pre-eruptive stage
Onset is sudden with mild or moderate
fever, pain in the back, shivering and
malaise.
This stage is very brief, lasting about 24
hours.
In adults, the prodromal illness is usually
more severe and may last for 2-3 days
before the rash comes out.

8. 2. Eruptive stage
In children the rash is often the first sign. It
comes on the day the fever starts.
The distinctive features of the rash are :
1. Distribution
2. Rapid evolution
3. Pleomorphism
4. Fever

9. Chickenpox rash

10. A. Distribution -
The rash is symmetrical.
It first appears on the trunk then comes on
the face, arms and legs.
Mucosal surfaces (e.g., buccal, pharyngeal)
are generally involved.
Axilla may be affected, but palms and soles
are not usually affected.
The density of the eruption diminishes
centrifugally

11. b. Rapid evolution
The rash advances quickly through the stages
of macule, papule, vesicle and scab.
The vesicles filled with clear fluid and looking
like "dew-drops" on the skin.
They are superficial, with easily ruptured walls
and surrounded by an area of inflammation.
The vesicles may form crusts without going
through the pustular stage.
Scabbing begins 4 to 7 days after the rash
appears.

12. c. Pleomorphism
It is characteristic feature of the rash, in
chickenpox.
All stages of the rash (papules, vesicles and
crusts) may be seen simultaneously at one
time, in the same area. This is due to the
rash appearing in successive crops for 4 to 5
days in the same area.
d. Fever
The fever does not run high but shows
exacerbations with each fresh crop of
eruption.

13. Laboratory diagnosis
1. Polymerase chain reaction (PCR)
2. Isolation of virus in cell culture from
vesicular fluid, crusts, saliva,
cerebrospinal fluid or other specimens.
3. Direct immunofluorescence assay

14. Control
1. Notification
2. Isolation of cases for about 6 days after
onset of rash
3. Disinfection of articles soiled by nose and
throat discharges
4. Antiviral compounds - acyclovir,
valaciclovir, famiciclovir and foscarnet

15. Prevention
1. Varicella-Zoster Immunoglobulin (VZIG)
Within 72 hours of exposure
For exposed susceptible individuals
particularly in immunosuppressed persons
2. Live attenuated varicella virus vaccine
between 12-18 months
Ex. Monovalent vaccine
Combination vaccines (MMRV) - 9 months
to 12 years.

16. Thank You