Daniel Kalla is an emergency room doctor based in Vancouver and the international bestselling author of 10 books.

His latest, We All Fall Down, is a thriller about the black death. Set both in the past and present, Kalla explores the plague caused in the medieval period, and how its effects would be felt if it were to break out today.

"I thought it was such a fascinating chapter of history. I heard about it from when I was very young. I was always fascinated by it, but I didn't know much about it. For me, the best way to learn about a subject is to write a novel about it. As soon as I started reading about it, I became consumed with it. I thought this was just so rife and the fact is we haven't seen the exact same pathogen that caused the black death probably in 200 years. I tried to speculate what might it be like if it came back today and how might it reflect on the historical occurrence of it.

"It's by far the biggest natural cataclysm to ever hit mankind. It wiped out up to 60 per cent of Europe in three years. In a time when there was no travel, it spread from Sicily to Iceland and Russia, in three years. It took Europe 500 years to reach the pre-plague level of population."

"The best modern day example I could come up with was ebola, which is such a devastating infection. I wanted to give [Alana] the absolute sense of panic because some things went wrong in West Africa at the time. I also wanted to give her a sense of the bureaucratic missteps if people were slow to respond.

"Panic brings out the worst in people. In medieval times, the Jews were scapegoated and that was one of the first examples of true genocides where they accused the Jews of poisoning the wells and mass murdered Jews across Europe. In my novel and the contemporary story, I imagine a scene where some Muslim extremists are initially suspected of spreading the plague and how they're scapegoated in modern times without much evidence. It gave me a chance to let people know that human nature is human nature and we sometimes risk returning to our basest instincts."

"There's this assumption we've defeated bacteria, but we've seen it with multi-resistant tuberculous coming back. There are so many examples of infections that we thought were things of the past that recur. Mother Nature is a clever adversary and it will always come up with something new. While we're always hyper-aware when an outbreak occurs, there's this sense of complacency between time. There's always going to be a next thread. You know there are lots of people out there, experts and specialists who are aware of that. The public and many of the medical community lose that sense, and it feels comfortable for a while."