[A Danish malaria epidemic?]

The article questions the accepted truth that "cold fever" (or ague) in the 19th century was malaria. It discusses especially in detail the characterization of the widespread epidemic in Zealand and Lolland-Falster in 1831 as a "Malaria epidemic", and alternative possibilities of definition are taken into consideration. The conclusion is in a certain sense rather deplorable as it is hardly possible to tell with any confidence which disease it was that killed so many, mainly older and poor people from the rural population.