In this Noir thriller, Sheila Bennet is the unwitting Patient Zero who came back from Cuba with a fortune in diamonds, and death in her veins. It turns out that her boyfriend, who persuaded her to smuggle the stones, has been two-timing Sheila with her own sister. He's able to fool Sheila for a while, and steal the diamonds, but when she finds out, nothing will stop her tracking him down. Meanwhile the authorities discover that Sheila's infecting everyone she meets with smallpox, and desperately want to bring her in, but Sheila refuses to submit.
It's not entirely clear why the authorities want Sheila. OK, she's infectious, but the end voiceover suggests they needed her for some other reason - as if she's the key to a vaccine, or has some vital evidence about where she contracted the disease. All that's a McGuffin, really; the point is, she's important, so they have to chase her.
Smallpox hasn't been a threat since its eradication in 1980, and it's becoming more and more difficult to understand, on an emotional level, the fear it once inspired. Intellectually we can look at its history, see its death count, and know how devastating it can be - but it's like trying to put yourself in the shoes of a soldier in the trenches of the Great War. Empathy only carries you so far; ultimately, you have to have been shot at to know what it truly is like to be shot at.
First comes the fever, and vomiting. Then sores in the mouth, and painful skin rash. Over a period of days this rash becomes fluid-filled bumps, which will eventually scab over and leave scars - assuming you survive. Fatality can be as high as 75%, depending on severity of the rash distribution. The overall rate is closer to 30% fatality. Death tends to occur in ten to sixteen days, accompanied by acute organ failure. If you survive, you're scarred for life, and might also go blind.
Image taken from Wikipedia: Content Providers(s): CDC/James Hicks
Let's talk gamification.
Given that Trail, Bookhounds and Dreamhounds are all set in the 1930s, it's reasonable to think that a character might have encountered, or contracted, the disease at some point in their careers. It could be an interesting twist, say, to an In The Blood drive - yes, it is in the blood, but because of a smallpox outbreak, not heredity.
However let's take this one step further, and say that a smallpox scare threatens the characters' lives or livelihoods in some way. Let's further say that the Patient Zero is someone the characters know, or work with, or are responsible for. George MacDonald Fraser makes good use of this last tactic in his short McAuslan story, Fly Man, where his narrator Dando has to go chasing over Cairo for his soldiers, while at the same time keeping the smallpox story very, very quiet for fear of starting a panic. Of course, two of the most dangerous have decided to go AWOL, and are armed, just to add to the fun.
'You must go through every club, canteen, dance-hall and gin mill in the in-bounds area,' says his superior, 'I want them all, you understand. No stragglers, nobody overlooked.'
Bookhounds is particularly useful for this, since the players are likely to have employees or co-workers, but in theory this could happen to any group. Someone you know & rely on has contracted smallpox, but either they don't know it yet, or they have other reasons for staying out of the authorities' reach. Your characters have to track down that person and somehow persuade them to come in from the cold - or the consequences could be dire.
All this, of course, without considering the Mythos. It's likely that anything with a biological makeup can contract diseases, so something like a Fire Vampire is probably immune to smallpox, but a ghoul, or Deep One Hybrid, isn't. Tracking outbreaks of smallpox could be an unusual way of tracking the movements of a ghoul colony, but a potentially more interesting question is, what happens at the fever stage? Suppose, in the case of an as-yet undiscovered Hybrid or ghoul changeling, the smallpox causes uncontrollable mutations, or spontaneous outbreaks of Idiosyncratic Mythos magic, as per Bookhounds. Or the afflicted taps into the Mythos and starts babbling secrets which, under normal circumstances, the poor soul doesn't know. Nurses, relatives, carers, would all be bombarded with secrets tapped straight from Cthulhu's psychic backlash, with consequences too terrible to think about.
This doesn't have to stay trapped in the 1930s. Even in the modern day there's the occasional scare, as with the retained stocks of the virus rediscovered in 2014, at an FDA storage facility in Bethesda. Imagine what the Esoterrorists might do with just the mystic threat of a smallpox bioweapon, or what the Conspiracy might want with strange vials filled with what might be smallpox - or might be something else again. Particularly in a campaign where the vampires have a Mutant background, there may be any number of reasons why the Conspiracy is keenly interested in dusty records of bioweapons research long past. Is this smallpox, or is this the Vampire Genome deliberately mislabeled as smallpox?
Finally, a Bookhounds scenario seed to speed you on your way:
A book scout of your acquaintance has fallen ill, shortly after telling you about a tremendously valuable find. What at first is thought to be ordinary fever is soon discovered to be smallpox, and the authorities are knocking on the characters' door with instructions to inoculate everyone the book scout has come into contact with. It transpires that several other people have fallen ill with the same symptoms, but these people had no contact with the book scout. However they might have had contact with the book. Just what tome is this, and what dreadful secret does it carry within those pox-ridden pages?
That's it for now. Enjoy!