CASE FOR MALARIA
Malaria has deeply influenced human history, impacting demographics, migration, warfare, and genetic evolution by conferring resistance through traits like sickle-cell anemia. The disease spread with human populations, contributing to societal changes and the fall of civilizations, such as ancient Rome. Its effects on population health have also driven cultural adaptations and even influenced economic phenomena like the transatlantic slave trade.
The disease, then called "Roman fever," was so prevalent in marshy regions around Rome that it contributed to declining agricultural productivity and may have even played a role in the fall of the Roman Empire.
The disease traveled with human populations and trade, spread by soldiers and merchants, influencing settlement patterns and the development of human communities. The relative resistance of Africans to malaria compared to Europeans and indigenous populations increased the profitability of the transatlantic slave trade, significantly shaping the racial landscape of the Americas.
Malaria has been a significant factor in many wars, often causing more casualties than actual combat, affecting military campaigns and contributing to broader conflicts and population movements.
Many historical games represent malaria, for example Victoria. We have jungle unhealthiness (partially due to malaria, I would imagine), but I feel like it's a little boring and not enough. DoC can come up with some cool effect also. Perhaps the easiest would be to simply deduct -10% health from any unit in Jungle tile adjacent to Marsh. Units cannot travel on Marsh tiles and we want to exclude cold region marshes.