Following the fall of the Austro-Hungarian Empire, Kirschner followed Professor Robert Doerr, an experimental pathologist,[11] to Amsterdam for further studies at the Koninklijk Instituut voor de Tropen (KIT), the Dutch Royal Tropical Institute.
While there, Kirschner undertook important work on the survival in the environment of the bacteria that causes leptospirosis,[2] and he and a colleague developed an effective vaccine against plague, testing early versions on themselves.
He and wife Alice, a gifted violinist from Vienna, survived and provided considerable covert assistance to other prisoners using his scientific knowledge.
[17] At the time of his arrival, New Zealand was considered to be free of leptospirosis, an assumption based in part on the absence of native terrestrial mammalian hosts.
[18] However, Kirschner noted that many mammalian species that could serve as hosts of Leptospira spp had been introduced to New Zealand, and that measures at ports to prevent rats being imported on ships were weak.