There were troop ships retuning to Canada with wounded soldiers after the First World War. I once did research about Dr. Frank Porter Patterson, who was involved. I'll look it up.
However, the nursing uniform reminds me more of English Nursing Sisters.
Here's a bit of Canadian history that might be similar:
Nursing Sisters Kathleen G. Christie and Anna May Waters were sent out to Hong Kong in 1941. The British hospital they were working at was taken over by the Japanese and they were sent to Stanley Internment Camp. They continued to care for injured Canadian soldiers in spite of the lack of food and medical supplies, ill-treatment from their captors, and the threat of tropical diseases. Waters reportedly made soup in a steel helmet because she had nothing else to use. When a letter from Christie to her father finally arrived in 1943, it was almost two years old at this point. It was about their time at the hospital before Hong Kong fell. The two were repatriated during a prisoner of war exchange in December 1943. After recuperating in Winnipeg, Waters rejoined her unit. She worked abroad the TSS Letitia, one of two Canadian hospital ships that were staffed by all women, and served in both the Atlantic and Pacific war theatres. Source: Christie, Kathleen G. (2001) “Report by Miss Kathleen G. Christie, Nurse with the Canadian Forces at Hong Kong, as Given on Board the SS Gripsholm November 1943,” Canadian Military History, Vol. 10: 4, 4. Accessed from:
http://scholars.wlu.ca/cmh/vol10/iss4/4