In 1888, Almanzo, and his wife Laura, both came down with diphtheria. While Laura had a milder case, Almanzo’s was more severe and with neuropathy complications that affected the muscles in his legs. He had temporary partial paralysis which impacted his ability to walk and permanently disabled him so that he needed a cane to walk.
It was largely due to his health that they left De Smet in 1890, as the physical labor required on a prairie farm was too difficult for Almanzo to do even after he recovered, although they did return to De Smet after staying in both Minnesota and Florida. They eventually moved to what would become the home for the rest of their lives, in Mansfield, Missouri.
For fans of the television show Little House on the Prairie, the show depicted Almanzo as having suffered a stroke rather than diphtheria which the real Almanzo suffered from, largely because many are unfamiliar with diphtheria today due to vaccinations.