Leiper discovered diurnal periodicity in Filaria Loa, as the worm embryos are found in the blood only during day, as an adaptation to the day-biting habits of their insect vector, a biting fly of the genus Chrysopa. This discovery was published in a single paragraph written by the editor of JAMA.  Digital facsimile from Google Books at this link.

(Thanks to Juan Weiss for this reference and its interpretation.)

Leiper identified the snail responsible for the transmission of Schistosoma mansoni and S. haematobium.

First paper in English giving a detailed account of the development of S. japonicum in the snail and its subsequent development in man. Atkinson, a surgeon in the Royal Navy, was a member of Scott’s Antarctic expedition. He was in command of the expedition's base at Cape Evans for much of 1912, and led the party which found the tent containing the bodies of Scott, "Birdie" Bowers and Edward Wilson. Atkinson was subsequently associated with two controversies: that relating to Scott's orders concerning the use of dogs, and that relating to the possible incidence of scurvy in the polar party.