New Study Coauthored by Bard Professor Felicia Keesing on Rodent-Borne Diseases Shows Connection to Loss of Biodiversity

ANNANDALE-ON-HUDSON, N.Y.—Felicia Keesing, David and Rosalie Rose Distinguished Professor of Science, Mathematics, and Computing at Bard, has published a study in Science with coauthor Richard S. Ostfeld examining diseases that are spread to people by rodents, and how our destruction of the environment makes those diseases more likely.

“Rodents as a group are infamous as disease-transmitters,” says Keesing. “But not all rodents are created equal. We were able to discern clear patterns in which ones are dangerous, which ones are not, and why.” Ostfeld adds, “Not only are the disease-bearing species predictable, so too are the environmental changes that help them proliferate.”

Many people think of all rodents as vermin, but only a small percentage (about 12%) of rodent species carry pathogens that can make us sick. These disease-causing rodents, including the city rats and house mice that infest human-occupied spaces around the world, tend to thrive when we destroy the natural environment. When biodiversity declines, the species that prosper are typically hosts for pathogens that can also infect people. In their review in Science, Keesing and coauthor Ostfeld explore what we know about this pattern, and how it plays out for three rodent-borne diseases that are all surging in the 21st century—Lassa fever, Lyme disease, and the plague. The results of their synthesis point to the importance of protecting and restoring biodiversity as a critical strategy for protecting our own health.

In their review, Keesing and Ostfeld focus on key traits of rodents that share pathogens with us, including “synanthropy” (living with and benefiting from human environments), while also considering the potential impact of drivers of global change such as climate change and biodiversity loss. Lassa fever, for example, mostly affects people living in West Africa who become sick each year through exposure to a virus shed in the feces and urine of a widespread rodent, the multimammate mouse. Keesing and Ostfeld show that environmental correlations between the virus and the rodent host’s ability to thrive may lead to increasing numbers of people at risk for Lassa fever as suitable habitat expands under global climate change.

Lyme disease, which was first described in the northeastern United States, is also strongly linked to rodents. The disease is caused by a bacterium that is shared with people through the bite of infected ticks. The animal that infects the greatest proportion of ticks is the white-footed mouse, with an infectivity of more than 90%. These mice thrive in human-impacted habitats from which other mammal species have disappeared, another example of how human impacts on the environment often have negative effects on our health.

Plague has caused notorious pandemics in past centuries, but cases of this rodent-borne disease are also surging in the 21st century, particularly in East Africa, northern Asia, and Madagascar. Hundreds of species of rodents can be infected with the bacterium that causes plague, but past pandemics are strongly linked to the spread of black and brown rats, which are also implicated in modern plague hotspots. These rats thrive in human habitats where other animals cannot.

The authors focus their review on rodent-borne diseases but the patterns they describe are true of other diseases as well, including diseases affecting wildlife, livestock, and plants. Species that thrive when we destroy natural habitats tend to be species that are also likely to spread pathogens. This gives renewed urgency to efforts to protect and restore natural environments around the world. Keesing states: “This review affirms that we need to act now on the knowledge that damaging the environment increases disease transmission and threatens our health.”

Read the study here.
About Bard College
Founded in 1860, Bard College is a four-year, residential college of the liberal arts and sciences located 90 miles north of New York City. With the addition of the Montgomery Place estate, Bard’s campus consists of nearly 1,200 parklike acres in the Hudson River Valley. It offers bachelor of arts, bachelor of science, and bachelor of music degrees, with majors in more than 40 academic programs; graduate degrees in 13 programs; eight early colleges; and numerous dual-degree programs nationally and internationally. Building on its 164-year history as a competitive and innovative undergraduate institution, Bard College has expanded its mission as a private institution acting in the public interest across the country and around the world to meet broader student needs and increase access to liberal arts education. The undergraduate program at our main campus in upstate New York has a reputation for scholarly excellence, a focus on the arts, and civic engagement. Bard is committed to enriching culture, public life, and democratic discourse by training tomorrow’s thought leaders. For more information about Bard College, visit bard.edu.

Website: https://www.science.org/doi/10.1126/science.adq7993

This event was last updated on 09-19-2024

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