A new study published in Science reveals that the deaths of over 1,300 children in the U.S. are linked to the mass die-off of bats due to a lethal fungus, white-nose syndrome. Bats play a crucial role in pest control, consuming massive quantities of insects, including crop pests. With their decline, farmers increased pesticide use by 31%, leading to a nearly 8% rise in infant mortality in areas where bats disappeared.
The fungus, Pseudogymnoascus destructans, which arrived in the U.S. in 2006, has devastated bat populations across the country. This loss triggered a surge in pesticide use, which, despite being within regulatory limits, has been linked to the rise in infant deaths. According to Eyal Frank, an assistant professor at the University of Chicago who led the study, the bat population decline provided a natural experiment to examine the environmental and health impacts of losing these insect-eating creatures.
Frank’s research found that counties affected by white-nose syndrome saw infant mortality rates 7.9% higher than unaffected counties. Pesticides, commonly used to replace bats’ natural pest control, were determined to be the main factor behind the increased infant deaths, highlighting the far-reaching effects of wildlife loss.
“Farmers did respond to the decline in insect-eating bats, and that response had an adverse health impact on human infants,” Frank said.
The Hidden Cost of Losing Bats
Bats, often overlooked in environmental conservation, provide immense value by naturally reducing the need for chemical pest control. They eat up to 40% of their body weight in insects each night, helping to maintain balanced ecosystems. As white-nose syndrome wipes out bat populations, human health is taking a hit as toxic pesticides fill the gap.
Researchers tested various factors, such as unemployment rates, opioid use, and weather patterns, but none explained the increased pesticide use and corresponding rise in infant deaths except for the loss of bats. The decline of bats created what researchers described as a “randomized controlled trial” across counties, making it clear that the absence of bats led directly to more pesticide usage and infant mortality.
Long-Term Impact of White-Nose Syndrome
White-nose syndrome has ravaged bat colonies since it arrived from Europe in 2006. The fungus grows on hibernating bats, producing white fuzz on their noses and killing colonies within five years. As the disease spreads across the U.S., it creates ripple effects throughout ecosystems and human health.
This study adds to growing research about how declines in wildlife populations can unexpectedly affect human life. For example, in a related study, the collapse of India’s vulture population has been linked to 500,000 human deaths due to rabies and other infections spread by unscavenged carcasses.
Columbia history professor David Rosner, who specializes in environmental toxins, emphasized the study’s findings. “We’re dumping synthetic materials into our environment, not knowing what their impacts are going to be. It’s shocking, but not surprising, that we discover these hidden costs every year.”
As the bat population continues to decline, the health consequences could grow. This research serves as a stark reminder of the interconnectedness of species and the dangers of ignoring the environmental toll of human activity.