Native American tribes in New Mexico are closing their borders and adopting strict self isolation measures in fear of a coronavirus outbreak within their reservations, according to the Associated Press. 

Small Native American pueblos across New Mexico are ramping up testing and self isolation efforts in fear that if they do get an outbreak, they won’t have the medical resources to combat it.

Tribal leaders fear that if their communities endure a bout of the coronavirus, it may decimate populations out of existence. 

“If the virus does reach us, that could be the end of Picuris,” said Wayne Yazza, the pueblo’s lieutenant governor, told the AP.

New Mexico’s 19 indigenous pueblos consist of constituencies of between 300 to several thousand people. Their populations have struggled with access to healthcare since long before the pandemic.

Public health officials have also warned that Native Americans, much like other minority communities, could be particularly vulnerable to the COVID-19 due high rates of conditions like diabetes and heart disease. 

“You hear about all these other big towns that are losing 10, 50, 100 — that’s already half of our whole tribe,” Picuris Gov. Craig Quanchello, told the AP. “We’ve got to do everything we can to protect our race here.”

In April, the U.S. Bureau of Indian Affairs warned that tribes could not put up checkpoints unless they consulted their state governments.

Some tribes, like the Oglala Sioux and Cheyenne River Sioux in South Dakota, have resisted calls from their states to reopen their borders.