Matt

>> If you have some evidence on either side let me know. <<

Whether they knew the actual mechanics involved is irrelevent.... what is incontestable is the fact that they knew that certain diseases spread from human to human via casual (or even indirect) contact.... and that they knew that people did NOT immediately evidence symptoms (too many folks came down with things days or even weeks after they'd been exposed to known victims, for it to be otherwise).

(And "active epidemic" is a misnomer..... in virtually all cases, outbreaks didn't simply appear out of nowhere, but instead could be traced by any halfway discerning person to recent contact with people traveling from regions where the disease in question was known to be present)

>> The people on the ships in question were not from areas with active epidemics. They did not know they were carrying all those diseases. <<

False. Europe was a hotbed of disease throughout most of the last millennium. (Summer was often called the "fever season" in recognition of outbreaks of diseases like cholera and smallpox that swept though major cities back then. Even earlier, during the height of the Roman Empire, those who could afford to left the city of Rome during this time.... in documented efforts to avoid the near annual epidemics).

On my part, over the years I have read numerous accounts of ships which precipitously fled harbors after outbreaks were reported there (so that they certainly knew they were fleeing "plague regions"), or where disease broke out onboard while in transit (so that they certainly knew they were carrying it).... even some cases where ships were forced to make premature landfall in order to quell major shipboard outbreaks of disease (hard to run a makeshift hospital in cramped quarters, with little more than stale food and water).

(Face it, Whites knew their societies carried diseases, that other humans were susceptible, and that they'd carried said diseases with them to the New World.... but they didn't let this stop them from coming here, contacting the Natives, or trying to make money off the process.....)

>> I could be wrong, but I am pretty sure that they were not aware of the extent of the spread. If you have some evidence on either side let me know. I am going to do some research on this, this week I hope. <<

Are you looking for references/citations, or specific examples? (I can provide some of either). As an example of European knowledge of the extent and spread of Old World diseases in the New World, consider the following (culled by historians from early Spanish accounts.... and from official "reports" sent back to the Crown).

1494—La Isabella founded on Hispanola (first Spanish town in New World). While still under construction, reports indicate that 1/3 of the White population fell sick in a 4-5 day period. (To the best of my knowledge, this was the first stages of a specific epidemic that swept through the Caribbean, killing a great number of Indians and depopulating entire islands... Some modern scholars feel that it was most likely swine flu, based on recorded symptoms and the fact that Columbus brought a herd of pigs with him on his 2nd trip, when La Isabella was built). Spanish records fully chronicle the depopulation (as part of their records dealing with exploration and "labor search"...).

Smallpox came to the New World on a Spanish ship in 1516. In early January of 1519, officials on Hispanola reported that a "grandisima enfermedad" had killed 1/3 of that island's (surviving) natives... By May 20th of that year the colonial officials estimated that 1/2 were dead. The disease, identified as smallpox, had spread to Puerto Rico by the end of 1518, and was decimating Indians on Cuba by mid 1519. Panfilo de Narvaez brought it with him (historians even know the name of the infected crewman!) when he sailed from Cuba to Mexico (intending to relieve Cortez of command), with the result that half the Indian population of Tenochtitlan ("Mexico City") died of it in 1520... and with similar results among tribes allied to the Spanish, once it quickly spread among their ranks (allowing Cortez to consolidate his conquests). (As an aside.... Indian doctors, whom many Spaniards regarded more highly than they did Spanish physicians, testified that communicable diseases of this mortality were unheard of prior to the arrival of the Spanish)

Spreading up and down the length and breadth of the Americas, smallpox reached Taintinsuyu (Inca Empire) in 1524, killing the Inca emperor and his chosen heir, plus half that nation's generals and untold numbers of it's citizenry... the resulting weakness (plus a lengthy civil war between two royal sons who had been unexpectedly made candidates for the succession) allowed Pizarro a relatively easy conquest in 1532.

1528+ Cabeza de Vaca and a handful of companions (one was a carrier for some disease or another) who'd survived from the Narvaez (or was it the Ayllon?) expedition, traveled among the Gulf Coast tribes en route to Spanish settlements in Mexico. They later related that soon after contact, half the population of any tribe they visited died.... (in fact, these men "paid their way" by pretending to offer cures for the diseases that followed them).

1539—De Soto found major towns recently depopulated by epidemics in "La Florida" (Earlier, Ponce de Leon had found no such indications).

1566—Juan Pardo similarly found major towns recently depopulated by epidemics in "La Florida".

....later Spanish expeditions found no trace of the populous chiefdoms reported by De Soto and Pardo, reporting instead a region with a greatly diminished population, who shunned the remains of the old ceremonial centers.

As far as English knowledge went, there are numerous documents relating to epidemics wiping out whole villages, and decimating regions. (Pay special attention to ships' logs relating villages found abandoned on return voyages, often with the bones of their occupants found strewn among their untouched possessions, or the recorded text of certain public Puritan "prayers of thanksgiving" for epidemics that were speedily depopulating New England of it's Native inhabitants.....)

Note also that when Raleigh finally got around to looking for the missing Roanoke colonist in 1590, his search was stymied by the disease induced extirption of the nearby Croatan Indians, with whom the Colonists had planned to take refuge in event of emergency... and from whom Raleigh had hoped to find word of their fate). Recall also the famous story of Squanto (home village wiped out by disease after contact with a European trading vessel), and the fact that Puritan immigrants to New England preferentially settled on village sites left depopulated by epidemics (thus saving them the onerous job of clearing their own fields). For that matter, the elderly Powhatan related to the English that he had "seen the death of his people" three times by disease during his lifetime, so that none of his contemporaries still survived save him.

(If you plan to research any of this for yourself in more detail, a few books that I recommend to start with are J. Leitch Wright's "The Only Land They Knew: The Tragic Story of the American Indians in the Old South" (best single overview I've yet seen on the history and racial interactions of that region), and Henry F. Dobyns' "Their Number Become Thinned: Native American Population Dynamics in Eastern North America" (his emphasis is on Florida, but has useful tables dealing with recorded epidemics throughout the Americas). A (somewhat dated?) classic I've heard of but not had the luck to read is P.M. Asburn's "The Ranks of Death", which was one of the first analysis to bring the serious impact of disease interactions to the attention of modern scholars. William MacNeil's "Plagues and People" and Alfred W. Crosby's "The Columbian Exchange: Biological and Cultural Consequences of 1492" are also worth reading.)

By the way, I deliberately avoided any mention of later (18th and 19th century) events, assuming that you were interested only in the early interactions?