 In October 1939, Zuelzer immigrated to the Netherlands, where she procured a position at the Institute for Tropical Hygiene, which was led by Wilhelm Schüffner.Her sister Gertrud Zuelzer, a noted painter, was arrested in September 1942 and sent to Theresienstadt after a failed attempt to flee Germany to Switzerland.Margarete sent Gertrud packages of clothing and colored pencils with which Gertrud drew portraits of other prisoners in exchange for food.