Well poisoning

Nearly 500 years later during the Winter War, the Finns rendered wells unusable by putting animal carcasses or feces in them in order to passively combat invading Soviet forces.

[3] Israel poisoned the wells and water supplies of certain Palestinian towns and villages as part of their biological warfare program during the 1948 Palestine war, including a successful operation that caused a typhoid epidemic in Acre in early May 1948, and an unsuccessful attempt in Gaza that was foiled by the Egyptians in late May.

[11] An outbreak of plague thus became the trigger for Black Death persecutions, with hundreds of Jews burned at the stake, or rounded up in synagogues and private houses that were then set aflame.

Walter Laqueur writes in his book The Changing Face of Anti-Semitism: From Ancient Times to the Present Day: There were no mass attacks against "Jewish poisoners" after the period of the Black Death, but the accusation became part and parcel of antisemitic dogma and language.

It appeared again in early 1953 in the form of the "doctors' plot" in Stalin's last days, when hundreds of Jewish physicians in the Soviet Union were arrested and some of them killed on the charge of having caused the death of prominent Communist leaders...

Similar charges were made in the 1980s and 1990s in radical Arab nationalist and Muslim fundamentalist propaganda that accused the Jews of spreading AIDS and other infectious diseases.

"[20] Israeli Prime Minister Benjamin Netanyahu stated in reaction, that Abbas had spread a "blood libel" in his European Parliament address.