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A trog, result of a severe TDC infection.

The Troglodyte Degeneration Contagion or Troglitic Degeneration Contagion (TDC) is a transformative and degenerative disease that plagues the inhabitants of The Pitt in both the city's earlier and later history in 2104 and 2277, meaning the disease has existed for at least 173 years. It turns people into monsters known as trogs.

According to Dr. Sandra Kundanika who came up with the term, TDC is the result of intensively concentrated ambient radiation exposure combined with the unique industrial toxins and pollutants in the region that surrounds what was once Pittsburgh,[1][2] and cannot be contracted by contact with the infected.[3]


According to Dr. Kundanika, all people who live in TDC-active areas experience skin lesions after a few weeks of exposure. These are reversible, as they may clear after a month or more away from the area. For many sufferers this is the full extent of the effect. For a certain percentage of people exposed to the toxins of the Pitt region, TDC also alters the brain chemistry and thereby produces psychological effects, turning the affected into wildmen.[1]

Approximately 20% of the adults exposed to the TDC lose higher reasoning and motor skills over the course of several years, degenerating into the feral mutants called trogs. Nobody has ever recovered from full degeneration, although there are rumors that trogs retain some memories and recognize the faces of loved ones.[1] While adults have a slight chance of experiencing full degeneration, children born in TDC-infested areas have a nearly 100% degeneration rate, turning feral within weeks after birth, with one sole exception.[1]


Marie, daughter of Dr. Kundanika and Ishmael Ashur, was born with a natural adaptive immunity to TDC, offering hope that one day a cure for the Pitt's whole population can be developed. So far, the efforts at synthesizing this cure have been slow-going, mostly because Marie is still a baby and that (being the only test subject) she must be treated with care.[4][5]


Troglodyte Degeneration Contagion appears in the Fallout 3 add-on The Pitt and in the Fallout 76 update Expeditions: The Pitt.


  1. 1.0 1.1 1.2 1.3 Haven terminal entries; research terminal, Trog Studies
  2. The Lone Wanderer: "Wait, slow down. Cure for what?"
    Wernher: "The Pitt is a mess. Nearly everyone who lives there is either sick, dying, or... worse. It's the water. And the air. You can't escape it. You stay there a few years, and no matter what, it'll get you. But the bastards who have my people, they've found a way to a cure it. And once they have that cure perfected, we don't stand a chance. So, we need the cure to bargain for our freedom."
    (Wernher's dialogue)
  3. The Lone Wanderer: "A cure? You're sick? Agh! Get away!"
    Wernher: "It's not like that. You can't catch it from me. The Pitt... it gets to you. It's the water, and the air. You can't escape it. You stay there a few years, and no matter what, it'll get to you. But the bastards who have my people, they've found a way to fight it off. And once they have it perfected, we don't stand a chance. So, I need you to come with me and help me get the cure. With it, we can turn the tables on them. Once we control the cure, Ashur will have no choice but to free the slaves."
    (Wernher's dialogue)
  4. The Lone Wanderer: "Wait, you mean she has a natural and transferable immunity of some sort?"
    Sandra: "Well, this is a nice surprise. Apparently, you and Ashur are the only other people who know anything about science in this place. Yes, it seems that our daughter was born with a naturally acquired immunity to any form of mutation. It's nothing short of a miracle, honestly. I'm still trying to figure out why, but she may just hold the key to stopping The Pitt's trog problem. Hell, maybe other types of mutations, too!"
    The Lone Wanderer: "Aren't you worried about hurting Marie?"
    Sandra: "Oh, no, these tests are perfectly safe. In fact, between the crib and her uncanny health, she's probably the safest child in the world! Ashur and I would never risk her health, and if that means it takes longer to develop a full cure, then, well... everyone else can wait."
    (Sandra's dialogue)
  5. Cure research