1948 "Cast thy bread" biological warfare campaign by Israel

Operation "Cast Thy Bread" (Hebrew: Shallah Lahmekha) was a top-secret biological warfare campaign conducted by the Haganah and the Israel Defense Forces (IDF) during the 1948 Arab-Israeli War. Officially confirmed by historians Benny Morris and Benjamin Kedar in a 2022 landmark study, the operation utilized typhoid bacteria to contaminate drinking water wells in Palestinian villages. 

Strategic Objectives

The campaign, which began in April 1948, aimed to achieve three primary military goals: 

• Prevent Return: To discourage and prevent displaced Palestinian Arab villagers from returning to homes captured by Jewish forces.
• Hinder Arab Armies: To disrupt the logistical capabilities and advancement of invading armies from neighboring Arab states.
• Scorched Earth: To compromise water supplies in Jewish settlements that faced imminent capture or evacuation, ensuring no usable water remained for advancing Arab troops. 

Key Figures and Leadership

The operation was not a rogue initiative but was orchestrated by the highest echelons of Israel's pre-state and early military command: 

• David Ben-Gurion: Israel's first Prime Minister, who authorized the overall program.
• Yigael Yadin: The de facto Chief of General Staff, who oversaw the military implementation.
• Yohanan Ratner: The operational commander who coordinated the campaign.
• Moshe Dayan: Served as an early field operative, acting as a smuggler to transport the biological agents from laboratory facilities to active military units. 

Documented Missions and Incidents

• Acre (Akka): The water supply was contaminated with typhoid, triggering a local epidemic that sickened dozens of local citizens and caused several fatalities. 
• Gaza Infiltration: In May 1948, two Israeli soldiers disguised as Arabs attempted to contaminate a crucial water well in Gaza to block the Egyptian army. The operatives were captured, court-martialed, and executed by Egyptian authorities. 
• Target Expansion: While initial operations targeted local Palestinian communities and the Egyptian line, the high command drafted expansion blueprints for operations into Syria, Lebanon, and Egypt, though these were never executed. 

Historical Legacy

The tactical execution of the campaign was overall amateurish and faced strong opposition from several prominent Israeli scientists and politicians. Consequently, it did not significantly alter the strategic outcome of the war. For decades, the Israeli security establishment actively classified and suppressed archival documentation regarding the operation. The structural precedents and informal research frameworks established during "Cast Thy Bread" later laid the groundwork for the formal creation of the Israel Institute for Biological Research (IIBR) in 1952.