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'

scripts/sweat_map.py. 85 departments in their 1880s borders. Across all of France the counts go together (rank correlation +0.35, shuffle p 0.001; 24 departments had both, 31 sweat only, 5 hantavirus only, 25 neither, p 0.01). But both simply rise toward the north (with latitude: sweat +0.33, hantavirus +0.57). Within the north-east (north of 47.5 N and east of 2 E, 21 departments) the match is zero (+0.01, p 0.47); north of 48.5 N it is slightly negative (-0.13). Normandy (Calvados, Manche, Orne, Eure, Seine-Inferieure: 31 sweat outbreaks) and the Paris basin had many outbreaks and have almost no hantavirus today (3 cases); the Ardennes, one of today's main foci (42 cases), had no outbreak, Doubs 2, Meuse 1. The Jura and Haute-Saone match (6 outbreaks each). Caveats: forests, farming and rodents have changed in 150 years, and 18th-19th century reports cluster where doctors were (Paris region).