pretty sure america has been doing this for sixty years

Biological warfare is as old as Antiquity. Lobbing diseased and decomposing bodies into a stronghold with a trevauchet or catapult was an effective way of demoralizing and contaminating the target, most often the rotted corpses landed in the water supply after which it's only a few weeks before the target succumbs to the siege. During the " Golden Age of Islam" when muslim moors, aided with intelligence by Spanish/Saphardim jews, were pouring into Europe by way of the Straight of Gibraltar, a common tactic implemented was in the form of espionage that involved muslim assassins breeching the perimeter of the stronghold, enclave or city and planting diseased body parts, excrement, blood or urine in strategic places such as the water and/or food supply, temples or wherever people were frequently concentrated. FYI...the main component of the Black Death of the 14th century was not the flea infested rat it was the decomposing, diseased human flesh that was so abundant because of the invading moors, a miasma thickened with the stench of rotted corpses is not healthy.