Sweating sickness followed seed-boom years, as modern European hantavirus does

Modern Puumala hantavirus outbreaks in Europe follow a chain: a warm summer, a bumper beech and oak seed crop the next autumn, a vole boom, then human cases. We tested the first link with the summer temperature reconstruction: was the summer two years before an outbreak warmer than the summer three years before?

France, 171 outbreaks at their own grid squares: slightly the opposite (minus 0.14 of a typical swing), chance of this high or higher 87 percent. England, 5 outbreaks: no difference (plus 0.01), 48 percent. A plain 'warm summer two years before' gave a hint in England (7 percent) but nothing in France (54 percent).

Verdict: no support for the seed-boom version. If the sweats were hantaviruses, they did not follow the mast cycle that drives Puumala today, or the temperature grid is too coarse to see it.