The Picardy sweat struck the same places where hantavirus infects people in France today
Opened and checked 27 October 2026. Heyman et al. 2014 wrote that 'Puumala infection still occurs in and around the same region today' but did not compare place by place. Department counts agree only in the broad sense that both are northern and eastern; inside the north-east they do not agree at all (rank correlation +0.01). The sweat's heartland (Normandy, Ile-de-France, Oise, Bas-Rhin) is not today's hantavirus heartland (Ardennes, Avesnois in Nord, central Aisne, Jura and Doubs), apart from Aisne, Oise and the Jura. This does not rule out a hantavirus (rodents and forests have changed), but the map gives it no extra support.
Tests we ran on this
- Passed 0.001 Do departments with more Picardy sweat outbreaks have more hantavirus cases today? Yes across France, but both are simply northern (see the next test). (decided before looking, 2026-10-27) · scoreboard
- No sign 0.47 Same match, inside the north-east only (so north versus south cannot fake it) No match at all: the north-south divide explained the first result. (chosen after looking, 2026-10-27) · scoreboard
How it connects
This hunch is about
English sweating sickness: what was it?
This hunch is supported by
Where the Picardy sweat struck (1718-1874) and where hantavirus infects people in France today (2021-2025) match only as 'north and east, not south and west' broad match only, none within the north-east
This hunch came from this step
Checked the Picardy sweat against a real beech seed record and against today's hantavirus map