Charles Nunn: The Big Picture on Human Health and Disease

It's pretty hard to pin down Charlie Nunn when you ask him to describe his science. He calls himself a behavioral ecologist, but get him wound up and he starts to sound like an epidemiologist or a primatologist. He joins Duke this term as a professor of both evolutionary anthropology and global health.

Nunn says his work fits in three big areas. Besides the evolution of sleep, he's interested in primate behavior and ecology, the work he started doing at Duke as a grad student with Carel Van Schaik. But most of his work lately has been focused on the distribution of infectious diseases across species -- including "spillover" from one species to another -- and how those distributions change with environmental conditions and human activities.

"I want to go into a community of hosts and understand the pathways of disease," he says in a sunny office in Biological Sciences that overlooks the statue of Knut Schmidt-Nielsen and his camel.

"Primates are kind of a paradise for parasites and pathogens," Nunn says. Our order of life is generally social, sexually active and long-lived. Primates also inhabit tropical and subtropical areas and are curious and interact with other species as predators, prey and co-foragers. Humans of course share many of these features with our primate relatives. 

The question is, do humans have more than their fair share of parasites? Nunn says there are about 1,415 parasites and pathogens that infect humans, but only 70 have been found in the gorilla.  This huge difference may be because we live in close association with other species, we store our food -- unwittingly inviting rodents into our homes -- we tend to live in crowded conditions, and that we're relatively sedentary because of all of the above.

The interactions of all of those factors with the infectious diseases and their hosts is where his ecology training comes into play. Lean and energetic, Nunn jumps from his chair to scribble a regression analysis on the white board, demonstrating what he means.


The details of how disease is distributed across species is only now coming into focus as faster genomic sequencing has arrived, Nunn says. The molecular view is finally giving a clear picture of how parasites and their pathogens move between species.

One particularly interesting community of hosts he wants to explore is the lemurs of Marojejy National Park in the highlands of northeastern Madagascar, where he will continue work he has done elsewhere in Madagascar while at Harvard. The Duke Lemur Center has recently established a new effort around Marojejy, called SAVA Conservation, and Nunn intends to partner with colleagues there to better understand disease vectors in the relatively unspoiled rainforest preserve. To get that picture, he's going to catch female mosquitoes shortly after they've enjoyed a meal and analyze the DNA found in their bellies to figure out what species they bit and what parasites the victim was carrying.

He'd like to know how the network of hosts and parasites was functioning in the first place, and then see how it adapts to environmental shifts like deforestation and climate change.

He hopes to do some of his sleep research in Madagascar as well, dovetailing with what biology emeritus researcher Peter Klopfer has been doing with lemur hibernation. "I really want to start having a bigger presence on that island," Nunn says.

Back in Durham, he'll be teaching "Human Health From an Evolutionary Perspective," in the global health major, which will include the "hygiene hypothesis" that argues autoimmune disorders and allergies might stem from having too few parasites and pathogens in our lives.

It actually does all fit together, he concludes. "We're linking non-human primates and infectious disease to human health. We'd like to be able to not just guess it, but show it."

Nunn lives in the historic district of Chapel Hill with his wife, biologist Sheila Patek, who is another new faculty member at Duke. They met in graduate school at Duke and have two children, aged 6 and 2.