If Brian Blais, Ph.D., had to pick a favorite zombie movie, Shaun of the Dead would bury the rest. Besides it being a comedic film about a 30-year-old man who’s charged with protecting his girlfriend and mother from a zombie apocalypse, Blais says the movie is the best example of zombie disease progression.
Serving as a Biological and Biomedical Sciences professor in Bryant’s School of Health and Behavioral Sciences, Blais uses entertaining examples to explain how disease and disease models work; this is how he and Caitlyn Witkowski ’14 conducted research that compares the zombie virus to influenza.
“The zombie virus is a bit more infectious than COVID-19, but less than the measles,” explains Blais.
The term zombie either originated from the African term “nzumbe” or Haitian Creole term “zonbi,” referring to a corpse that’s been reanimated via witchcraft. While the word today still refers to the reanimated dead, their on-screen depictions have evolved from the voodoo zombie to resemble disease dynamics. Blais says the fictious creatures come from the imagination and mixing up several diseases; situations have occurred where people appeared dead but wake up later.
“There have also been times in history where people have been mistakenly buried alive, so you'd hear screams from graveyards,” Blais says.
For their research, Blais and Witkowski used the Susceptible-Infected-Recovered disease model, which describes disease dynamics and provides insight on prediction and control. Blais notes that the infectiousness of a disease can be determined by looking at the rate at which people get infected and recover. Since real zombie data is nonexistent, the two watched zombie movies and estimated the imaginary creatures’ growth rates at specific points throughout the films.
“We used the model in the same way someone would track the number of people infected with the flu or COVID-19,” Blais says. “If people are getting infected more rapidly than recovering, then the spread of the disease is much higher. If they're recovering faster than they're getting infected, then the disease will peter out.”
Blais and Witkowski’s research received attention from Hollywood. Jeremy Kleiner, World War Z producer, spoke with the two about a potential movie sequel and asked for feedback on ideas.
In addition to zombie-related research, Blais collaborated with Marijn Jaarsma ’22 on a similar project that compared vampires to diseases that infect small populations — such as towns, schools, and households.
Since there are fewer vampires than zombies, Blais and Jaarsma used stochastic dynamical modeling when collecting data from vampire literature, TV shows, movies, and fan pages; they looked at how the population grew over time and found the mockumentary series, “What We Do in the Shadows,” provided the best dataset. Blais notes that the timescale for vampires is longer than other diseases because they live for an extended period with their stories taking place over decades or centuries.
The vampire myth dates to medieval times and links to several diseases whose characteristics are associated with vampires. These diseases include porphyria (patients experience light sensitivity), rabies (biting and repulsion to garlic or light), and catalepsy (patients were often buried alive, so their corpses had fresh blood).
“There was a New England vampire craze in the late-1800s that was essentially a response to tuberculosis,” Blais says. People surmised that patients with the wasting disease were losing energy because a recently deceased relative was a vampire and decided to suck the energy out of them, Blais notes.
With research on zombies and vampires in his back pocket, Blais remains on the hunt for more imaginary comparisons. His latest idea is to study werewolves and disease seasonality.
“Some diseases have ups and downs, and a lot of it has to do with the environment. While most of that is due to human behavior, there can be other diseases that biologically go up and down based on human physiology,” he says.