By Laura Sumner Coon

A large white semitrailer sits under the searing Guatmalan sun  on a dried patch of earth in the  corner of “the Ranch.” After one of the first missions, at team drove the semi, stocked with dental chairs, exam tables, medicine cabinets and shelves the distance from Wisconsin toward the equator.

Eleven months out of the year, it sits unnoticed. But in January, the advance team lugs their water bottles and muscles over to the semi, where they are joined by a few local men who transfer the sun-baked stored items from the semi to a flatbed trailer.