This group has its origins in the aftereffects of the death of Prince Makatiel in 1348 AD, and has grimly held on ever since. Its members were Servitors of Disease who traded most of their freedom and dignity to Saminga in exchange for their continued existence; each one of them bitterly resents the trade. Even their Word-Bound are distinctly considered second-class servants in the hierarchy of Death. It was, perhaps, inevitable that they would form a society dedicated around recovering their former glory.
It is not entirely clear that Saminga is unaware of this group, or that he would particularly care about them even if he did.
Purposes and Goals
To advance the fortunes of former Servitors of Disease. It's also considered a good idea to kill as many humans as can be possibly managed.
Organization and Membership
Theoretically, every former Servitor of Disease belongs to Contagion, and indeed, all of them have at least heard rumors that there is some sort of organization out there looking out after Makatiel's Orphans. Generally speaking, for most that's as far as it goes; in fact, for most the rumors are all that are really necessary. Orphans of Disease will look out after their fellow Orphans for 'the sake of the cause', while regular Servitors of Death might do the odd favor in order to score some points. This is not to say that there is no formal organization - only that it is actually very small, and decidedly fractured. In the end, anybody with the desire to further Contagion's aims and the ability to accomplish them can legitimately claim to be a member.
It should be noted that Word-bound Orphans of Disease have no inherent rank in the group. Many of Makatiel's former Servitors are unimpressed by the way that his most trusted servants failed to be around for the Prince's demise (this is especially true of the demons who themselves were hiding).
Abilities and Resources
The primary tools that Contagion has at its disposal are Disease's old Band and Servitor Attunements (obviously, their Rites no longer work). Generally speaking, the Attunements are useful mostly in the corporeal plane - but, given the general backwater that is Abaddon, this is no great hardship.
Members of Contagion generally try to be thought of by other demons as being the sensible and clever Servitors of Death. This was at first through habit - their former Prince had somewhat rigorous standards of decorum - but has been kept up as part of their long-term goals. Contagion values useful connections with the various power centers of Hell, and so will actively seek out opportunities to make mutually beneficial arrangements with potential allies. Both sides being inherently selfish creatures, this rarely works out as well as can be hoped, but it is now known that if you want something from Death, speak to someone from Contagion.
Unfortunately, the list of those who know this includes Asmodeus.
The internal machinations of the genocidal monsters who serve Saminga is no real interest to the Host, except of course for determining who needs to be excised from the Symphony most. Contagion, for its part, avoids the forces of Heaven whenever it can reasonably manage it.
The Demon Prince of Disease was always one of the more hostile members of the Horde when it came to ethereals - he always considered them potential allies of Heaven, even after the Purity Crusade - and Makatiel's vindictiveness is still remembered by the various pantheons, centuries after his destruction. If more members of Contagion worked on the ethereal plane, this might be more of an issue/
There were never really all that many Servitors of Disease - Makatiel had high standards, and preferred quality to quantity - and most of them disappeared into InfSec's clutches in the aftermath of their Prince's elimination. The relative few that survived did so because Saminga was possibly the only entity in Hell that actually liked Makatiel, or at least avoided a certain instinctual revulsion towards the Habbalite. In exchange for protection, the Prince of Death made it clear that his new Servitors would be expected to follow the aesthetics that he set out, not the ones of his late colleague; given the situation, the Orphans of Disease reluctantly agreed - and were thus spared. Of course, the Demon Prince of Death did not do very much to protect those Servitors of Disease that sought out his service, but absent orders from Asmodeus himself the Game was unwilling to push the issue against an actual Prince.
And not much else has happened since then... which infuriates the members of Contagion. It came to a considerable shock to the well-trained, subtle, and proactive former Servitors of Disease that not only was their new master uninterested in properly maintaining Makatiel's highly effective suppression of human medicine; he was actively interested in shutting down the program entirely. This had apparently been a matter of some debate between the two Princes. Saminga knew that increasing the population meant also directly increasing the eventual number of dead people; besides, mass death scenarios require large populations to draw from.
Unfortunately, the Prince of Disease was always a bit paranoid when it came to humanity, so the Prince of Death could never convince his colleague that keeping medicine corrupted was counter-productive. But once Makatiel died, Saminga no longer had to; he could merely command Makatiel's Orphans to step back and watch their life's-work crumble away from non-use... and they did. Fuming (and in a few cases, distraught), but they did. Since then it's been widely assumed that Contagion merely exists as a mutual-assistance sub-group within Abaddon. If this is not true - if inside that group there remains a hard core of demons prepared to restart up the old ways (or even Makatiel's scheme to destroy humanity), it's very, very well hidden.
Then again, it would have to be.