Once the deadly virus started spreading all over the world, devastated communities struggled to confront a pandemic they did not fully understand. Soon the finger-pointing started as people looked for someone to blame: It was the Jews.

It was the mid-14th century, and the Black Death had begun to ravage Europe. In the end, it reduced the overall population by about a third. Rumors spread that it was a Jewish conspiracy, and as a result Jews suffered terrible persecution.

“When there are big epidemics, people get scared,” said Rutgers University’s Martin J. Blaser, a historian and professor of medicine and microbiology. “They often look to blame some kind of intruder or stranger. It has happened especially with the Jews.”

Throughout the European continent, it was said that Jews were poisoning wells with the plague. Blaser said there is evidence of European Jewish communities being massacred during this time, a period he described as the “worst persecution of Jews” before the Holocaust.

One source of the conspiracy theory may have been the lower death rates among Jewish communities. Blaser said that could have been related to the fact that once a year, Jews cleaned out their grain supply for Passover, lowering their chances of being exposed to rats, carriers of the plague.

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From the Black Death all the way up to the measles outbreak in 2019, Jews have been used as scapegoats for outbreaks of disease, Blaser said.

Jews in New York City were blamed for last year’s measles outbreak, which disproportionately affected Orthodox Jewish communities. Health officials believe it was more easily spread in the tight-knit community because of the large number of children in each family, extensive international travel and low rates of vaccination. The Anti-Defamation League reported a spike in anti-Semitic incidents related to the outbreak.

Interestingly, it seems that Jews were not blamed for the Spanish Flu of 1918, the influenza pandemic that killed an estimated 50 million people around the globe. Jews even played a pivotal role in fighting it. San Francisco’s health department was headed by a number of Jews, including Lawrence Arnstein, who helped organize the Red Cross response to the disease. Matilda Esberg, president of the Congregation Emanu-El Sisterhood, was also involved in overseeing the response.

During the current coronavirus pandemic, Chinese and Asians have been blamed and discriminated against because the disease originated in China. Asian Americans have faced racist attacks, and there have been reports of Chinese businesses seeing a downturn in customers.

Blaser sees parallels to how Jews were treated during past outbreaks of disease.

“It’s the same mob mentality,” Blaser said. “Finding a victim. Unfortunately for Chinese people, they’ve borne the brunt of this so far.”