You are looking at a biological weapon which was used in war about 3300 years ago. The story starts when the Hittites,people who lived in north-central Anatolia from the 18th century BCE, were weakened by plague around 1335 BCE. The Hittites were then attacked by the Arzawans from Western Anatolia triggering then Anatolian war which lasted between 1320 and 1318 BCE. Even though the Hittites were weak, they managed to defeat their enemy in two years and one theory is that their secret weapon was disease ridden rams and donkeys.
To support the bioweapon theory, tablets dating to the 14-13th century B.C., describe how a ram and a woman attending the animal were sent on the road, spreading the disease along the way. "The country that finds them shall take over this evil pestilence," the tablet said. The practice was soon understood by the Arzawans who also reacted by sending their own infected rams on the road in the direction of the enemy troops.
"Even older evidence for ancient understanding of contagion comes from Sumer (modern Syria). Archaeologists have found several royal letters on cuneiform tablets from the archives of Mari, a town on the Euphrates River. The letters, dating to 1770 B.C., forbid people from plague-ridden towns to travel to healthy towns, and warn people not to touch or use the personal belongings of infected victims," Mayor said.[Sick Rams Used as Ancient Bioweapons]