A Different Sort of Family History: Telling the Life Story of Pathogens
You get a cold, and it’s annoying, but not the end of the world. But if you contract something more serious—HIV for instance, or flesh-eating disease—it’s another matter entirely. Why is it that some infectious diseases run such a deadly course, while others remain relatively benign?
As Canada Research Chair in Mathematical Biology, Dr. Troy Day is working to understand this crucial question. He uses techniques from applied mathematics to understand the enormous variation in the harm different pathogens cause.
A major part of Day’s work is understanding something called “disease life histories.” These are the patterns of transmission, mortality and recovery that occur during an infection.
HIV, for instance, has a disease life history characterized by essentially no recovery, but with a long asymptomatic period of transmission. Measles, on the other hand, causes a much shorter infection, with transmission and mortality largely overlapping.
With such a range of disease life histories, simply cataloguing all of them is challenge enough. However, Day goes beyond that, using mathematical models to try to understand, even predict, the development of pathogens in individuals, and to seek to know how these different patterns evolved.
In a world where people live in ever-closer quarters, and can travel from one corner of the globe to the other faster than ever before, understanding the life cycle of pathogens is vital for 21st-century public health. By helping us understand the life histories of diseases, Day is giving policy-makers and emergency planners the tools they need to keep the public safe from this potentially disastrous threat, while at the same time helping the wider medical community better understand the wide range of pathogens that result in so many trips to the doctor’s office each year.