During the Black Death which ravaged Europe during the 14th century the ethnic group which suffered the least was the Jews. The question is why did this group of people not lose as many of it's members as other groups?

The Black Death killed off proximately 75 million people in Europe, half the population, and yet the Plague affected substantially fewer Jews than gentiles. The Black Death was caused by the Bubonic Plague, at the time they did not know that bad hygiene which allowed bacteria to spread was one of the main elements responsible for the spread of the plague.

The Black Death spread when a human was bitten by an infected rat flea and so where ever there were rats there were fleas and the plague spread. It follows that those who kept themselves and their homes clean would suffer the least. The plague was also contagious and contact with an infected person transmitted the disease.

Washing of handsObservant Jews wash their hands at certain times of the day and under certain circumstances while saying a blessing. Jews have to wash their hands after using the toilet, before and after eating and after leaving a cemetery. In those days washing was not that popular and clean water not that accessible so people preferred to walk around with a "pocket full of posies" rather than washing. When gentiles in the 1400s did wash it was infrequent and not always with clean water. Clean water was often not readily available.

Family purityThe Jews have ritual baths which the Jewish women visit once a month, a week after they finish their periods. For this purpose the Jewish women are required to thoroughly clean their bodies before immersion in the baths. Thus during the plague the Jewish women got a good bath at least once a month which gentile women did not. Jewish men can also go to the mikvah before Shabbat or Jewish holidays to physically and spiritually cleanse themselves. The water used in a Jewish ritual bath is collected rain water, so that the Jews were not exposed to any disease carrying water during these baths.

The Jewish burial lawsJewish law says that the bodies of deceased Jews must be buried as soon as possible following death and if at all possible within 24 hours. This meant that unlike the gentiles, Jews would have the decaying dead bodies out of the house within three days at most. This reduced the chances of rats and flees (the carriers of the Black Plague) being attracted to the dead body lying in the front parlor. This Jewish custom also meant that the whole burial process left the infected and decaying body less exposed to the Jewish people.

Another point relating to this is that because the Jews were buried so quickly their deaths were often not recorded in the death records. The Black Death toll perhaps does not record the correct number of Jews who died. The Jews were also a closed community and may not have even deemed it necessary to report the deaths to the authorities.

The laws of Kashrut (Kosher)The laws of a kosher kitchen require meat to be salted and soaked this application of salt also served to kill off any bacteria left on the meat. If rats or fleas had come in contact with the raw meat, the salting and soaking would help to eliminate the bacteria left.

Passach CleaningPerhaps even the fact that every Pass over Jewish law requires the home to be completely cleaned and every corner swept, wiped and dusted could have contributed to the small number of Jews dying in the Black Plague. At least once a year, during Passover, any rats, fleas or food which could attract these creatures was cleaned out of the home.

The Jewish laws requiring washing of hands and the cleansing of the body, as well as the Jewish laws of Kashrut helped to protect the Jewish community from deadly bacteria during the Black Death. Although fewer Jews died of the plague itself many more died through persecution when the Jewish were blamed for causing the plague.