A Killer Whisky — Nancy M. Bell

The 1918 influenza pandemic strikes Calgary, Alberta, Canada. The Great War rages overseas. While her husband fights in Europe, Katharine works in a doctor's office to support her children and her brother, a wounded veteran. One night their neighbour suddenly takes sick and dies. The attending doctor concludes the man died from influenza, but Katharine suspects someone laced his whisky with a drug that mimics the deadly flu's symptoms.