|
|
|
Health Care Agency
Public Health Services
Epidemiology & Assessment
(714) 834-8180
Fax: (714) 834-8196
Email: EPI@ochca.com
Health Referral Line
(800) 564-8448
(800) 801-7100 TDD
|
|
|
 |
|
|
|
Chickenpox (varicella), which infects millions of children each year in the United States, is the disease most frequently confused with smallpox. There are key differences between the two diseases:
|
SMALLPOX (Variola) |
CHICKENPOX (Varicella) |
| Smallpox
incubation |
7-17 days |
Chickenpox
incubation |
14-21 days |
| Smallpox
prodrome (illness prior to rash) |
2-4 days |
Chickenpox
prodrome (illness prior to rash) |
minimal/none |
| Smallpox
distribution |
1. Lesions initially tend to develop on the face and extremities, progressing to the trunk of the body.
2. Rash found on palms and soles. |
Chickenpox
distribution |
1. Lesions initially tend to develop on the trunk of the body, progressing to the face and extremities. Lesions also tend to be more abundant on trunk than on face and extremities. 2. Rash rarely found on palms and soles. |
|
Smallpox
depth of rash |
Deeply embedded |
Chickenpox
depth of rash |
Superficial |
| Smallpox
progression of rash |
Lesions develop and progress at the same rate. |
Chickenpox
progression of rash |
Lesions appear successively and progress at varying rates. |
| Smallpox
scab formation |
10-14 days after rash onset |
Chickenpox
scab formation |
4-7 days after rash onset |
| Smallpox
scab separation |
14-28 days after rash onset |
Chickenpox
scab separation |
<14 days after rash onset |
| Smallpox
communicable period |
From rash onset until all scabs have separated (3-4 weeks after onset of rash). Most infectious during the first week of rash, after prodrome. |
Chickenpox
communicable period |
As long as 5 days (but usually 1-2 days) before rash onset until all lesions are crusted (usually) about 5 days after rash onset). Most infectious 1-2 days before rash onset and for first few days of rash. |
For further information regarding smallpox:
contact Orange County Public Health/Epidemiology: (714) 834-8180
or go to:
JAMA consensus article: Smallpox as a Biological Weapon:
http://jama.ama-assn.org/cgi/reprint/281/22/2127.pdf
Information adapted from: Los Angeles County Department of Health Services, Acute Communicable Disease Control
|
|
|
|
|
