Where Predators Are Scarce, Mongooses May Transmit More Disease

In the wilds of Botswana, a pathogen called Mycobacterium mungi has a very clever strategy for infecting the banded mongoose. A relative of the pathogen that causes the lung disease tuberculosis in humans, this pesky germ spreads from animal to animal through scent marks, which mongooses deposit in their habitats as a form of scent-based communication.

This strategy capitalizes on a behavior that’s crucial to mongoose survival, ensuring the microbe’s success, says Kathleen Alexander, a wildlife biologist at Virginia Tech, in a statement. However, when a mongoose senses a nearby predator, it becomes less likely to leave its scent behind, disrupting the spread of bacteria, according to a new study published in the journal Frontiers in Ecology and Evolution.

In environments with fewer predators, however, a mongoose will continue marking its scent and in doing so, create so-called “superspreading” landscapes rife with infection, Alexander explains in a statement.

To conduct their experiment, Alexander and her former graduate student, Carole Anne Nichols, used radio collars and camera traps to monitor the movements and interactions of roughly 500 banded mongooses in Botswana. Their results confirmed that animal behavior and disease transmission go hand in hand, shaking out into distinct “districts” across the mongoose’s natural habitat.

In high-traffic, predator-rich environments, such as urban centers or national parks, the mongooses maintained constant vigilance, devoting their energy toward scanning the horizon and readying themselves to flee. This hyperawareness likely kept them safe from large threats—but it also minimized their contact with kin, reducing the likelihood that M. mungi would spread, reports Natalie Parletta for Cosmos.

“If you're running from a predator, you’re not stopping to leave a message for other animals,” Nichols says in the statement. “You’re running for your life.”

But the opposite was true at tourism lodges, where predators are scarce and food—often left by human hands—is abundant. Here, the mongooses spent a good amount of time scent marking, creating ample opportunities for the pathogen to be deposited on, and picked up from, a bevy of surfaces.

Previous studies by Alexander and her colleagues have pulled back the veil on how animal behavior shapes the spread of disease. These new findings, however, add another layer of nuance to transmission, highlighting the role of environments—something that could someday help researchers physically map pathogen-heavy “hotspots” within a creature’s known range.

And as humans continue to encroach on once-wild habitats, these disease dynamics could easily affect our own health as well, according to Cosmos.

“Our results suggest an urgency in understanding how landscape types influence animal behavior and how these interactions might increase or decrease the potential for disease,” Alexander says in the statement. “It matters where an animal lives and how it behaves in that environment.”

Katherine J. Wu | | READ MORE

Katherine J. Wu is a Boston-based science journalist and Story Collider senior producer whose work has appeared in National Geographic, Undark magazine, Popular Science and more. She holds a Ph.D. in Microbiology and Immunobiology from Harvard University, and was Smithsonian magazine's 2018 AAAS Mass Media Fellow.