Types of smallpox

Smallpox was described in several clinical types, depending on the severity of illness and how the rash looked. The type mostly depended on the host's immunity and the virus strain.

Variola major The more serious form, with about 30 percent mortality in unvaccinated people. It is divided into the following types.

• Ordinary type: the most common (about 90 percent of cases), with a classic rash of distinct or confluent pustules.
• Modified type: a milder illness with fewer and faster-healing lesions, seen mostly in people who had been vaccinated earlier.
• Flat (malignant) type: the rash stayed flat and soft and did not form raised pustules. It was very severe and usually deadly.
• Hemorrhagic type: bleeding into the skin and organs, almost always fatal, and more often seen in pregnant women.

Variola minor (alastrim) A milder disease caused by a less virulent strain, with fewer than 1 percent of patients dying.

Variola sine eruptione A fever without rash, mostly in people with partial immunity. It was recognised through laboratory testing.

Other pox diseases Mpox, cowpox, chickenpox and others are separate diseases, caused by different viruses. They should not be confused with smallpox.

Ayurvedic view (interpretive) Texts sometimes classify Masurika by dosha predominance and by the colour and spread of the eruptions. This is a traditional classification and cannot guide diagnosis or treatment.

When to see a doctor Any new fever with spreading blisters should be assessed. Call 112 if the person is breathless, bleeding or very drowsy.