Smallpox (Variola virus) and Chickenpox (Varicella zoster virus)

Smallpox (Variola)

Feature

Chickenpox (Varicella)

Variola virus

(Orthopoxvirus)

Causative

agent

Varicella-zoster virus; VZV

(Herpesvirus family)

12 days (7-17 days)

Incubation

period

15 days (10-21 days)

• Deep seated

• Appear in single stage

• Evolution is slow

Rash

• Superficial

• Appear in crops (Pleomorphic)

• Evolution is rapid

• Dew drop rashes

• Centrifugal

• More concentrated on peripheral
areas (Palm, Sole)

• Extensor surface

Rash

distribution

• Centripetal

• More concentrated on central
areas (Face, trunk)

• Flexor surface

Subsidies with appearance of rash

Fever

Rise with each crop of rash