Stages of smallpox

Smallpox moved through predictable stages. Knowing them helped health workers recognise cases and decide when a patient was contagious.

1. Incubation (7 to 17 days) The virus multiplied inside the body. The person felt well and was not contagious.

2. Initial symptoms (2 to 4 days) High fever, severe headache, backache and vomiting. The person was unwell and might become mildly contagious near the end of this stage.

3. Early rash (about 4 days) Red spots appeared on the tongue and in the mouth, then on the face and across the body. This was when the person became most contagious as mouth sores shed virus.

4. Pustular rash (about 5 days) Spots became raised, then filled with clear fluid and then with pus. The skin was painful and the fever could return. Complications were most likely in this stage.

5. Pustules and scabs (about 5 days) Pustules dried and formed scabs. The person was still contagious.

6. Resolving scabs (about 6 days) Scabs fell off, leaving pitted scars. The person was contagious until all scabs were gone.

7. Recovery Once the final scab fell, the person was no longer contagious. Many survivors had permanent scars, and some lost sight or had joint damage.

Ayurvedic view (interpretive) Classical texts describe stages of eruption and maturation of Masurika, linked to doshas. This is a historical framework only.

Emergency note Any suspected smallpox-like illness is a public health emergency. Contact a doctor and health authorities immediately. For severe breathlessness or collapse, call 112.

Remember Smallpox was most contagious during the rash stages, until the last scab fell off.