Incline Village Epidemic
Not sure if anyone has gone down this track. If XMRV is propagated via immune system activation, possibly due to secondary virus or viral load, then could this be the major difference between sudden and gradual onset XMRV.
If the Lake Tahoe cohort was also infected with a rapid onset virus which ignited XMRV replication, then what will be significant is not just that they had XMRV but what that secondary trigger virus was. Genetics as a determinant does not explain why everyone in the Tahoe group came down with rapid onset (unless they were all cousins, of course). Far more likely that the group already had XMRV which is slow to replicate under most circumstances, but the circumstance changed to induce rapid replication. And if not a secondary virus, perhaps some other trigger.
Perhaps when the dust is settled on the XMRV issue someone will look closely at the triggers. Maybe categorise them according to how effectively they contribute to XMRV propagation. For example EBV may be a slow trigger or CMV a rapid trigger and so forth. Or a measles vaccination may be a rapid trigger.
I've spent a lot of time trying to understand what happened in Incline Village and discussing the topic with Erik Johnson, a member of the cohort who has mostly recovered through what he calls "extreme avoidance" of mold and other biotoxins.
This is my current understanding. Please note that it may not be exactly what he believes (he tends to share information rather than hypotheses).
In 1984/85, a microcystis (poison cyanobacteria) bloom was especially problematic on Lake Tahoe. A bright green algae was notable throughout the area, especially on the beach and in the woods.
Erik already was aware of his reactivity to toxic mold and other biotoxins. He thus noted that the "bright green not-grass" was having an effect on him. He also was reacting to various buildings in the area, including Truckee High School.
At about that same time, he noted a stronger version of this "stuff" coming up through the sewer vents in Incline Village and (I believe) Truckee. It made him feel somewhat sick as well. He went to Dr. Cheney and complained of what he described as "Chronic Fatigue," though this also had a neurological component to it.
Then the "Yuppie Flu" swept through the area. On August 5, 1985, Erik caught that "flu." After that, he became far more affected by the "whatever" that was coming up through the sewer vents. The "stuff" (apparently toxic mold) in his own house made him sick as well. His previously fairly mild reactions to these substances moved up to being "life threatening," constituting the symptoms he was experiencing.
His observation was that people who were living/working in particularly bad buildings, or who were living in homes that were adjacent to sewer vents, were more likely to get the "flu" and much more likely to get what later was called Chronic Fatigue Syndrome subsequent to it.
By scrupulously avoiding the "whatever" in buildings and outside, and by decontaminating (showering and changing clothes) after being hit with it, Erik managed to recover the majority of his health. He now works a full-time job, exercises vigorously and regularly, and lives a basically normal healthy life. He previously had all the Canadian Criteria symptoms except the bladder infection; now, he has only a few residual cognitive ones (including the disappearance of his formerly good math abilities). Having to be really careful about avoidance is annoying but better than living in agony, he has.
I find this story interesting because it suggests that there were two new things that happened in 1984/1985 in the Lake Tahoe area. One was the "flu" that swept through. The second was the microcystis bloom and the "whatever" that established itself in the sewers.
It's my tentative belief that the epidemic consisted of several components.
1. Substantial previous exposure to very bad buildings (e.g. Truckee High School) or to the "whatever" coming through the sewer vents.
2. Genetics predisposing people to being biotoxin responders. (However, as at Truckee High School, a particularly large exposure was capable of making anybody sick.)
3. Exposure to the virus that ramped up reactivity to these biotoxins from mild-ish to severe.
4. Possibly other factors (e.g. accumulated toxic burden of mercury, stress) were contributors increasing likelihood or severity.
A question is what the "Yuppie Flu" was. One possibility is that it was XMRV. However, I'm of the impression that this virus may have a longer incubation period than was noted in the fast spread in the Lake Tahoe epidemic.
If that's the case, then it could be that this was just an ordinary flu that triggered the XMRV to activate.
It's also possible that it was not a viral infection at all, but rather a big biotoxin exposure that appeared to be a flu, that caused the XMRV to activate. (Ritchie Shoemaker describes certain biotoxin exposures that appear to be "flus" in Desperation Medicine.)
Again though, much of this is speculative on my part. I am putting it here not because I am claiming to have the answer, but because it seems to me that more people should be considering the question.
Best, Lisa