Wikipedia has this animated gif showing the spread of the plague in Europe. Apparently the plague never reached Iceland, the bulk of Poland, the area around Milan, Andorra, and the extreme north of Russia. No explanation is offered in the article. Did these places intentionally isolate themselves from their neighbors, or was it due to environmental reasons?
On the other hand, while googling I found a few pages stating that Iceland was “hit hard” by the plague, although none with solid citations. So is the map/article wrong?
A lot of it may be simply be an artifact of the data (or lack of it). I imagine whichever data set they used (which being from the 14th century can’t have been too exhaustive to begin with) didn’t include numbers for iceland.
The Andorra/Milan thing is more interesting, I could imagine the mountain communities of the Pyrenees could have been isolated enough to avoid it (thislink seems to suggest they go off lightly). No idea what the story is behind the grey patch around Milan.
In fact comparing the two, the map on Wikipedia looks like it was taken directly from the map in that book. Which was based on the data of Dr Elizabeth Carpentier.
I’ll throw out the obvious guess that it never reached the extreme north of Russia because hardly anyone lived there and it conducted very little trade (or it just wasn’t included in the data set). It’s possible that the grey areas in northern Italy and Andorra were just supposed to represent the Pyrenees and the Alps, where very few people lived, and the fact that it seems to include Milan was just a mistake.
Although having said that I googled it quickly and a number of websites seem to claim that Milan did avoid a major outbreak somehow.
The gap covering most of Poland is very strange. I’d guess that has to be something to do with the dataset - there can’t be a genuine reason why the plague skipped that specific area, can there?
If this piece is accurate (it cites “How a mysterious disease laid low Europe’s masses” by Charles L. Mee jr.; Smithsonian, February, 1990; pages 66-78.) it might explain the Milan mystery.
Also outbreaks got much worse in the summers and less in the winters, and people who lived in large, populated areas who could afford to often fled for the countryside every summer. Maybe Milan had a larger population of people who could afford to travel and available countryside locations with low populations nearby.
Just to mention that some time ago, I too was looking at a map of the great plague and noticed several small spots apparently unafected, and wondered about it. They were some in several countries, although I can only remember France and Spain at the moment.
A previous poster mentionned a lack of data as a possible explanation, but I assume we don’t have data about every single place in Europe, hence that the default stance would rather be to exclude a peculiar spot only if there’s a known reason to do so.
It’s possible that some areas weren’t good environments for rats, or that rats hadn’t colonised them, or that the rats in those areas were isolated from the general rat population.
Also an area may be remote enough that a carrier would die before they could travel there; like northern Russia. Or, the population travelled/mingled enough outside that there was a generally large immunity by the time it reached the location. If there are suficient number of immune nurses around, the infected person does not usually infect their attendants. This is why the plague would disappear and reappear every generation or so as the immune population died off.
IIRC the Black Death was notorious because not only was it spread by fleas and rats, but also it was originally the pneumonic strain and was spread by coughing.
I’m going by memory here, so any or all of this may be wrong:
Iceland was hit around 1400, after the period covered by the Wikipedia illustration. Evidence suggests that at that time, Iceland did not have rats, so plague transmission would have had to be pneumonic.
(There are alternate theories out there that say the Black Death partly involved a simultaneous epidemic of a different disease, such as anthrax or a hemorraghic fever similar to Ebola. If so, those could account for rat-free transmission. I’m not qualified to evaluate the credibility of those theories.)
Milan and some other cities were supposedly more effective at quarantining themselves against outside travelers.
I don’t think there’s a settled answer as to Poland. Some say that it had lower population density at that time, others cite supposed differences in the type of grain grown there. Other historians suggest that Poland was indeed hit by the plague and that it is simply a lack of historical sources that make it look like it escaped.
Only in the first stage: once a rat’s flea has “successfully” infested one human, that human can by touch or cough* infect dozens of other humans without any need for rats to be involved.
In many towns the typical scenario was of people fleeing an infected town to the next town, but already carrying the disease unknowingly. It took some time for people to catch onto strict isolation as the best way to deal with it, like closing the gates of the town no matter how people wailed in front of it. (Occasionally, bread and food might be thrown over the wall, but only if available).
If you’re including the part of Poland, such as the Poznan/Posen province, that lay in Prussia for some years later, indeed the records are very scanty. I’m going off some book I read a couple of years ago, but a lot of this land was undrained swamps and uninhabited forests. There just might not have been enough population to transmit.
But when the (church) records exist, they’re goldmines of information, such as about cholera outbreaks in the late 1830s. Cause of death tends to be meticulously recorded in the late 18th and 19th centuries.
Sorry I don’t have a cite, my information is from a PBS program…most likely either Nova, or Secrets of the Dead…maybe that program that Alan Alda hosts.
There was at least one case of a village hit by the plague where most of the population survived. Some descendants of that population are found to have a genetic mutation which confers immunity. The leading theory is that there was an earlier, undocumented, plague outbreak in the area and the village population was made up of the survivors.
Apparently if you have two copies of this mutation, then you never get sick, and if you have one copy you get sick, but probably survive. The offspring of two of the sick but survivors have a 75% chance of passing full or partial immunity to their children, and the offspring of a parent that is fully immune will have at least partial immunity. Because populations were less mobile in early times, even after several generations you could still have a lot of immunity left in a population.
Interestingly, this same mutation works against HIV, so people descended from plague survivors have some small fraction that is fully or partially immune to HIV. Because the black death never infested Africa, there is virtually no resistance to HIV on that continent among the indigenous population.
As for Iceland: Aboard a ship, plague would infect and kill or disable the entire crew pretty quickly, especially when stressed by North Atlantic seas and weather. It is entirely possible that a ship that carried the plague was ipso facto incapable of getting there.
Rats do well pretty much anyplace humans live. But remember, it wan’t the rats that spread the disease to humans, it was their fleas. I’m not an expert on the little monsters, but I know they thrive in warm, humid environments and don’t do so well in arid/semi arid places.
Secrets of the Dead: Mystery of the Black Death. Video for the full program is not available on PBS’s website. The program has been uploaded to a video hosting site, but since I’m not sure if it’s legal, I’m not comfortable linking to it here.
