In this podcast, we discuss smallpox, the only disease successfully eradicated from mankind. Destruction of smallpox has eliminated much suffering in the world, but the disease lurks in the shadows threatening to re-emerge.

If I could be honest for a moment, today’s topic is one that

my nightmares are made of

What is smallpox?

Most of us probably have heard of it, but many of us may not

be sure exactly what it is

Smallpox is an orthopox virus with the official name of

Variola

CDC photograph

Smallpox is the only human disease that has been

successfully eradicated

As far as we know it currently only exists in the freezers

of the CDC and the Russian State Centre for Research on Virology and

Biotechnology, known as Vector

We have nothing to fear from smallpox…as long as it stays

there

Smallpox: How is it spread?

There are two strains, variola minor and variola major https://ourworldindata.org/smallpox

Variola minor has a case fatality of less than 1 percent,

while the case fatality rate of variola major can be 30%

Smallpox passes from person to person through coughing and

sneezing

Smallpox is incredibly infectious, one study showed that a

inhaled single smallpox particle was capable of causing disease

https://www.cdc.gov/niosh/nioshtic-2/20037359.html

There are few microorganisms that can successfully

accomplish this however, historical data indicates that transmission is

generally more difficult

Smallpox: What are the symptoms

Smallpox is named for its characteristic rash of pustules

that covered the body https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1069029/

Once infected, it takes about 10-14 days for symptoms to

develop

The first symptoms are very non-specific can easily be

mistaken for a cold

The patient is most infectious during this period, when they

are most likely to be able to spread it

Next the rash covers the body in ~24 hours

V0031460 Gloucester smallpox epidemic, 1896: Ethel Cromwell Credit: Wellcome Library, London. Wellcome Images [email protected] http://wellcomeimages.org Gloucester smallpox epidemic, 1896: Ethel Cromwell, aged about 14 years, as a smallpox patient.

For the next three weeks the pustules continue to grow, then

scab over and fall off

Areas were the pustules formed are likely to be evident for

life

If death occurs, it is generally from total exhaustion,

toxins and low blood-pressure

Death usually occurs 10-16 days after the onset of symptoms

It is difficult to piece together from the historical record

how many actual smallpox cases there were, but Swedish data indicate that in

peak years, smallpox would account for as many as 7 out of 1000 deaths

https://ourworldindata.org/smallpox

It has been estimated that from 1920-1978 there were over 11

million cases

The development of a heat stable,