Don't know why. Nobody really knows why, because no one is completely sure what it was/is. Some say it may have been an enterovirus, which would make it a hyper-active cousine to Polio, others a hantavirus, which would make it a hyper-active deadlier version of the "Korean hemorrhagic fever" that knocked out thousands of our troops during the Korean War. Both of these disease are connected with our RNA (messenger DNA). Hantavirus are generally associated with rat droppings, but as we will not below: not always.
For our quick blurb:
The Pessimist's Guide to History (updated)
Doris Flexner and Stuart Berg Flexner, Harper Collins, NY NY, 2008
1485: Outbreak of English Sweating Sickness
Sweating sickness first appeared in England in 1485 and spread rapidly among the populace. Apparently healthy individuals were struck down and died of the disease overnight. Largely confined to England, seating sickness killed thousand in epidemics that occurred in 1485, 1506, 1517, 1528, and 1551. It seemed more severe among the rich than the poor.
After what turned out to be what was the last epidemic, a report was written by physician, John Caius. It is of interest mostly because it shows how heavily languages change over time and is close to unreadable. The best portion is where the learned writer has to make excuses for why he is writing it in the vernacular English, rather than Latin or Greek.
John Caius, 1552, from a Cambridge 1912 edition of Caius' Works.
I wolde geue none example or comforte to my countrie men, (whom I wolde to be now, as here tofore they haue bene, comparable in learnyng to men of other countries) to stonde onely in the Englishe tongue, but to leaue the simplicite of thesame, and to procede further in many and diuerse knoweleges bothe in tongues and sciences at home and in vniuersities, to the adournyng of the common welthe, better seruice of their kyng, & great pleasure and commodite of their owne selues, to what kinde of life so euer they shold applie them. Therfore whatsoeuer sence that tyme I minded to write, I wrate y^e same either in greke or latine.
I think this is is vernacular still common to parts of Canada, particularly after they have had a few at the local pub, so maybe some of our Northern friends can help us with it.
Note that hetravirus was argued to be an unlikely candidate, because it was not known to be transmitted directly from people. However, that has proven to be untrue:
Hantavirus pulmonary syndrome outbreak in Argentina: molecular evidence for person-to-person transmission of Andes virus, Padula et al, Instituto Nacional de Enfermedades Infecciosas, 15 February 1998
So just another fun little think to look forward to in a spic-n-span post-apocalyptic spic-n-span world . A rat turd disease with wings. If it were fiction, it would turn us to zombies.Although human infection principally occurs via inhalation of contaminated rodent excreta, our results with Andes virus show the first direct genetic evidence of person-to-person transmission of a hantavirus.