In the United States the first outbreak of poliomyelitis, 26 cases, was in Boston in 1893, at the same time as its citizens were desperately spraying the just-invented insecticide lead arsenate to combat the plague of imported gypsy moth grubs that was denuding their trees.

Then the formula for lead arsenate was published in 1894, so people could mix up their own to use against a variety of pests including the codling moth whose worms damaged their apple crops. Use of the insecticide became much more wide-spread, as did outbreaks of poliomyelitis, which now included deaths. Outbreaks were usually in summer and autumn when apples and other fruit and vegetables were sprayed. [Read more…]