It seems as though Hell on Wheels intended some sort of underlying thematic connection between last week's Trial of Bohannon episode, 'One Less Mule,' and this week's 'Cholera.' It's a surprisingly sedate one, even though the series likely could have had a field day with the biblical/spiritual implications of the embattled southerner committing cold-blooded murder, only to see that act followed up by an outbreak of cholera sweeping through the railroad town. In fact, if the series did intend some sort of connection, it's the first time it has done so with such a degree subtlety as to make any correlation not a part of the actual text – which is, in and of itself, admirable for a show that likes such elements more on the obvious side of things.
Instead, the nasty infection is quite literally traced back to a rat (and who knows what else) that's managed to drown in the town's water supply and get a fair amount of Bohannon's workforce sick. While the unembellished interpretation of illness sweeping through Hell on Wheels is surprising, it soon becomes clear that cholera is really just a plot device intended to put Bohannon and the Swede just a little bit closer to the reunion that's been hinted at all season.
While the Swede is busy assuming the identity of the Mormon bishop he murdered so he can gain entry into Fort Smith (which will hopefully lead to all sorts of crazy Swede antics), Bohannon finds himself in desperate need of some Gatorade or Pedialyte to replace all those electrolytes he's rapidly loosing as a result of having drunk the cholera-rich water back in town. Sadly, he's about a century away from a deliciously salty fruit punch or lemon-lime flavored beverage, and has to settle for some spring water offered to him by a nearly feral child with a knife who's been hanging out around his family's furniture that the Swede left behind when he was finished with all the murdering.
Perhaps the nasty infection is intended to convey just how hopeless things appear to be in Hell on Wheels, and how the town itself seems to be tainted wherever it springs up. That's certainly the outlook Eva has, as she convinces herself that handing her child over to Declan Toole is the right thing to do, even though it'll really bum Elam out after he's had such a good day of building windmills and pumping fresh water back into the town he's sworn to protect. The infection's even spread to the increasingly strained relationship between the McGinnes brothers, as Mickey and Sean have completely switched roles, and now the whisky-swilling pimp Mickey has a better grasp on life than the suddenly sycophantic Sean, who practically takes responsibility for Durant's murder of a U.S. Senator.
In the end, despite a tenuous thread running through the episode and, perhaps, the season as a whole, the thread is getting weaker and weaker with every passing episode. What started as a search for redemption has turned into an exceedingly familiar routine of murder and betrayal; events that carry importance in the moment, but hold little meaning for the overall story.
Hell on Wheels continues next Saturday with 'It Happened in Boston' @9pm on AMC.