English soldiers in Ireland suffered very much from the quartan ague, which is associated with malaria.Ireland has a moist climate, and in those days much of the land was undrained and quite marshy. The assumption is that mosquitoes, which are carriers of malaria, thrived in that environment.As far as I know, there were various places in England in the 16thC that carried the same health warning - I think Essex was notorious, but I'm working from memory.The use of scientific methods to figure out historical fact is dodgy because of the lack of essential data. Plus I'm not sure of the latest thinking on this topic. I don't think the ague is related to the sweating sickness of the mid tudor period.Link here for a definition of the term (scroll down about 35%):"Ague: Intermittent fever. This term appears to be derived from a Gothic word denoting trembling or shuddering. [Hoblyn1855]Intermittent fever; often used in the same sense as chill or rigor. [Dunglison1874]An intermittent fever, attended by alternate cold and hot fits. The interval of the paroxysms has given rise to the following varieties of ague: an interval of 24 hours constitutes a quotidian ague; of 48 hours, a tertian; of 72 hours, a quartan; of 96 hours, a quintan. [Hoblyn1900]Malarial or intermittent fever; characterized by paroxysms consisting of chill, fever, and sweating, at regularly recurring times, and followed by an interval or intermission the length of which determines the epithets quotidian, tertian, etc. Synonyms: fever and ague; intermittent fever; periodic fever; malarial fever; marsh fever; paludal fever; miasmatic fever. [Gould1910].Febris intermittans. A febrile condition in which there are alternating periods of chills, fever, and sweating. Used chiefly in reference to the fevers associated with malaria. Archaic term for Malarial Fever. [Dorland]"Aigue" entered English usage in the 14th century, having crossed the channel from the Middle French "aguë". The word share the same origin as "acute." It descends from the Latin "acutus" meaning "sharp or pointed". A "fievre aigue" in French was a sharp or pointed (or acute) fever. [Medicinenet]http://www.antiquusmorbus.com/English/EnglishA.htm
Romney Marsh in Kent has had a history of malaria, though now not present. I believe that it was definitely an issue in the 1560s. There's a few reaserch papers out on malaria and Romney Marsh, particularly concentrating on the 17th & 18th century but with a reference or two to the 16th century.
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