Yes hard to believe that way back in 1754 but British troops fleeing from the battle with Indians are said to have left behind blankets which where deliberately infected with Smallpox yet some historians debate if this actually happened during this battle
How effective it was against the Indians is debated to this day. But the British are known to have used small pox against the Indians even into the revolutionary war and possibly against American troops.
Small Pox was so feared at Fort Pitt they set up a isolation hospital several miles away in Crafton
to care for troops who had it.
So it is not inconceivable that those blankets left on blanket hill where in fact infected with small pox. today it is not the once feared disease it once was because vaccines and better hygiene have eradicated it for the most part to 3rd world county's but it still pops up on occasion.