The collapse of an animal population in the US has been linked to the deaths of thousands of children, a new study claims.
Bats have been dying by the millions in farming hotspots across the nation due to a deadly fungus that began to rise in 2006.
Farmers have long relied on the winged animals as natural pesticides because they eat at least 40 percent of their body weight in insects each night, but workers have been forced to spray more toxic chemicals to compensate for the loss.
Pesticides have been linked to increased risk of birth defects, low birth weight and fetal death.
The new analysis linked the increase in toxic chemicals since 2006 through 2017 to the deaths of of 1,334 infants across 1,185 counties in 27 states, with a majority on the East Coast.
The invasive fungus, called Pseudogymnoascus destructans, causes a disease called white-nose syndrome (WNS) that has killed 6.7 million bats in the last 18 years.
Bats are known to feast on at least 40 percent of their body weight in insects a day, many of which are crop pests.
But the deaths have forced farmers in affected counties to spray 31 percent more pesticides each year, the analysis found.
This has corresponded with an increase in infant mortality rate linked to pesticides by eight percent.
According to the study, for every one percent increase in pesticides, the infant mortality rate increased by .25 percent.
The counties worst affected are mainly in the eastern and southern regions of the US, with New York, Michigan, Louisiana and Main experiencing bat population collapses.
Eyal Frank, the study's author and assistant professor at the University of Chicago, analyzed county-level data on the detection of white-nose syndrome in bats, pesticide use by farmers and other health indicators, including infant mortality.
When farmers spray pesticides on their crops, wind and water can carry it away from the initial site, creating off-farm exposure for other residents in the area, according to the study published in the journal Science.
Higher levels of agrichemical pollution are detected during the height of farming season, which extends from April to September.
Pesticides have been linked to negative health impacts including an increased risk of chronic diseases like cancers, neurological disorders and development delays and can cause acute poisoning.
Frank said farmer's increased pesticide use correlated with the increase in internal infant mortality rate, excluding those who died in accidents or homicides.
'Bats have gained a bad reputation as being something to fear, especially after reports of a possible linkage with the origins Covid-19,' Frank said.
'But bats do add value to society in their role as natural pesticides, and this study shows that their decline can be harmful to humans.'
The fungus can spread through infected bats but it can also be carried from cave-to-cave on humans' clothing and gear.
It can grow on a bat's ears, nose and wings and can invade their deep skin tissue, causing WNS which results in dehydration, starvation and death.
Pseudogymnoascus destructans is native to Europe and Asia where bats seem to be unaffected, but is believed to have been first introduced in upstate New York by a tourist in 2006.
It was found in a cave that connected to a commercial cave which sees 200,000 visitors annually.
Since the fungus was discovered, it has rapidly spread at a rate of 200 miles per year impacting a total of 38 states thus far, according to the Centers for Biological Diversity.
It grows best in damp caves where bats typically hibernate and thrives in cool temperatures that hover at about 57 degrees Fahrenheit.
There are 13 confirmed bat species that have been infected with WNS including the long-eared, little brown and tri-colored bats.
The northern long-eared bat has been the hardest hit by the disease. It's population has declined by as much as 99 percent in several eastern US states.
