Interesting bit from the Wiki article on
Ylaven/Lanth (SM1916): "Around 20 years ago* there was a totally unprecedented earthquake that leveled most of the poorer areas of Chicago. Hundreds lost their lives in the debris. Several ore mines collapsed killing dozens more. . . . In the immediate aftermath of the quake
there was an outbreak of severe cold like symptoms. Nearly a hundred people were killed before it was brought under control. There have been no reports of the disease before or since."
Sound like anything that affected
ANNIC NOVA's previous (and current) crew?
Notably, Ylaven is 2 parsecs from Victoria. One week in Jump would be long enough for symptoms of the lethal disease to manifest, which would have the crew in a desperate panic on arrival at Victoria. This panic could have led to a misjump that terminated in the coreward/trailing corner of Regina subsector -- right where it is found at the beginning of DA1.
But it's not mentioned in DA1, so who knows?
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* The wiki article is not clear as to what date "...around 20 years ago" is relative to. It follows the "During the Fifth Frontier War" section that describes Ylaven's history up to 1120ie, so "... around 20 years ago" could actually be referring to a date between 1100-1103ie. rather than 1086ie. This would align with the first sightings of the ship as mentioned in DA1.