By Matthew Phelan, Senior Science Reporter for Dailymail.Com
16:37 01 November 2023, updated 17:11 01 November 2023
- Vampire bat habitat is moving north at a rate of 6 miles per year due to climate change
- “Natural invasion” is already costing the Mexican livestock industry $46.7 million per year.
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Swarms of tiny, bloodthirsty vampire bats spread their wings farther north, toward the U.S.-Mexico border.
Scientists led by a team from Virginia Tech said they expect a “vampire bat invasion on U.S. soil in five to 20 years,” with sightings now just 30 miles from Texas.
Colonies of the two-inch-long creatures have long infested cattle ranches south of the border, extracting blood from livestock in a parasitic manner.
Bats are expensive for Mexican breeders $46.7 million annually due to the deaths of rabies-infected animals, according to a 2020 report from the United States Department of Agriculture (USDA).
Researchers believe warming temperatures are making North America more hospitable to these bloodthirsty creatures.
Previous USDA reports estimate that the entry of vampire bats into South Texas could drain between $7 million and $9 million from the local livestock industry in deaths from bats alone. rage.
But bats could also be costing lives, as rabies-infected specimens travel up the continent, spreading the deadly disease.
“This is a difficult situation that we would like to address as quickly as possible, so vigilance is crucial,” Texas Farm Bureau spokesperson Gary Joiner told Wired.
“There is a lot of concern about this bat species in agriculture because of its ability to transmit disease, injure livestock and cause infections,” Joiner said.
“Rabies is the most obvious problem due to livestock welfare and the potential for infection of humans.”
While human deaths from rabies are currently rare in the United States, killing only one to three people per year according to the US Centers for Disease Control and Prevention (CDC), these deaths are increasingly caused by infected bats.
Although vampire bats rarely bite people, the creatures will strike when threatened, and their expanding habitat means more chance of hostile interactions.
Efforts to vaccinate bats themselves against rabies could backfire, according to Luis Escobar, an assistant professor of wildlife conservation at Virginia Tech who has tracked the bats’ northward march.
“Rabies can reduce bat populations by 10 to 80 percent,” Escobar said. “Imagine if we had too many vampire bats because we didn’t have this virus.”
Some wildlife managers have experimented with a rabies vaccine gel that wild-caught bats then distribute to each other in their roosts, where the social species groom each other.
But Escobar fears that this technique could cause vampire bat populations to explode.
“We don’t know what the ecological effects of disrupting the circulation of this virus in bats will be,” he said.
Instead, the researchers, along with USDA officials, suggest that ranchers may want to follow the lead of their Mexican and Colombian counterparts and vaccinate their livestock and pets.
And local governments may want to vaccinate the wildlife that vampire bats prey on.
“Landowners will want to consider whether or not they should vaccinate their animals,” said Mike Bodenchuk, director of the USDA’s Wildlife Services division in Texas, while trying to allay exaggerated fears.
“They will not cross the border in their millions,” he stressed. “It’s going to be a slow trickle for a while.”
This species of vampire bat, Desmodus rotundustends to thrive in warm, humid regions where temperatures do not drop below 50 degrees Fahrenheit.
Late last month, Virginia Tech’s Escobar and a team of international conservation scientists published the results of their review of 120 years of climate records, seasonal vampire bat captures and other data, such as deaths due to livestock rabies recorded by the regional epidemiology information system. Rabies surveillance.
The researchers found that “the bat’s geographic range has significantly shifted its distribution northward,” as they wrote in the journal Ecography, “a natural invasion of northern Mexico at an average rate of 9.76 km per year (6.06 miles per year). »
Escobar and his co-authors added that their large database analysis matches previous work using DNA evidence to trace bat migrations.
“Genetic evaluations have demonstrated that D. rotunda of Mexico is rapidly expanding its range northward,” they noted. “(but) disagreements between previous modeling efforts have shown that further study is still warranted.”