In honor of the triumphant return of Sanditon this spring, GBH Drama put together an email series to accompany each episode. For those who missed the emails, we now present them here (lightly edited for formatting).

Given what we knew about the returning cast for this season, I can’t say I’m totally surprised that Sidney has died off screen, but still, ouch: I know a lot of people (IRL and in Sanditon) are very upset. While we wait to unpack the mystery of why he took his fateful trip to Antigua in the first place, you may be wondering: what’s the deal with yellow fever anyway? Glad you asked! Here's the story:

The virus that causes yellow fever is transmitted by mosquitoes, and mostly causes fever, chills, and aches, and in some cases severe liver disease (that’s where the name comes from: liver disease often results in jaundice). Nowadays it’s very preventable (vaccines to the rescue!) but in the early 1800s, yellow fever epidemics were a huge problem. Unfortunately for Sidney, he’s exactly the kind of person who’d be more likely to get sick in this era: a traveler with no built up immunity.

Even worse, at the time, doctors and scientists had a very different idea of how diseases spread: some thought outbreaks were caused by astrological forces, some thought they were caused by bad air. With that in mind, Lady Denham’s mistrust of Dr. Fuchs doesn’t seem so weird: nobody really knew what they were doing! It wasn’t until the late 1800s that Cuban doctor Carlos Finlay proposed the idea that mosquitos were to blame for yellow fever. American history nerds may know the next part: Walter Reed (he of the Army Medical Center), concerned with the impact yellow fever had on troops during the Spanish American war, set out to prove Dr. Finlay’s hypothesis. While Dr. Reed often gets the credit, he made it clear that he got the idea from Finlay, so we have to give props to both. Having figured out the disease vector (how it spreads) it was then possible to eradicate yellow fever in Cuba and Panama. But unfortunately, that wouldn’t be for about another hundred years after Sanditon is set.

Looking for more of the history behind Sanditon season 2? Check out our other coverage on our Sanditon hub here.