Every disease was far more powerful in Henry's time.  The Sweat was one of many.  I recently read somewhere that Europe suffered from this disease also, but it was not as virile as it was in England.

Thousands still die yearly from the flu.  An estimate I saw here in America stated that 36,000 people die here a year from flu.  And we have vaccines for some flu types.  Henry's England had no such medical cures.

They lived on an island from which there was no escaping a disease once it hit their shores.

Impish_Impulse said:

It might have been several illnesses with similar symptoms and outcomes. References could be maddeningly vague to modern thinking. Take “consumption”: it often meant tuberculosis, but not always. It was simply a description of a disease that made one wither and waste away; it was ‘consuming’ them. That could describe other illnesses besides TB. “Ague” is usually assumed to refer to a bout of malarial fever, but in reality could describe any illness that causes alternating bouts of fever and chills.

http://discovermagazine.com/19…..gsickn1161

The above article from 1997 suggests that the “English sweat” might well have been a form of hantavirus. It’s intriguing.

Later article – 2001 – on the “sudor anglicus” (forum won’t let me blockquote):

Abstract: A rapidly fatal viral infectious disease appeared in England
in 1485, persisted for the summer months and disappeared as winter
approached. This pattern of infection re-appeared in 1508, 1517, 1528,
and finally 1551. The epidemic never returned. It had no respect for
wealth or rank, and predominantly attacked males between the ages of 15
and 45 years. The incubation period was frighteningly short and the
outcome normally fatal. The symptoms of acute respiratory disease and
copious sweating were characteristic, providing the name `the English
sweating disease’. It was never in the big league of killer epidemics,
such as plague and influenza, but its pockets of instant lethality in
communities gave it a special ranking of horror. The infective cause of
this disease remained a total mystery until it was compared with
Hantavirus pulmonary syndrome (HPS) in 1994. The strength of this theory
is examined in this paper, and it is concluded that, although there is a
close resemblance, HPS does not match the English sweating disease
completely and positive identification of a possible rodent carrier for
the latter was not established.

http://findarticles.com/p/arti….._n8939673/

The coolest part about the Sweat was how fast it killed people.  The first symptoms could appear in the morning and you could be dead by evening–I don't care who you are, that's just impressive.  I'm guessing that the virus probably had a lengthy incubation period before the victim ever started displaying even the earliest symptoms.  This would have made person-to-person transmission insanely easy as you'd be infecting people before you were even aware you were a carrier–sort of like the chicken pox.

I have no evidence supporting this, but I suspect that whatever virus caused the Sweat is probably an illness that is still out there today, but, due to evolutionary pressure, it has been changed at the molecular level since the 16th century.  Thus, the symptoms of the Sweat may be different than they were or the virus may be less virulent than it was then.