The individual—whose name, age, and sex were not released by local authorities—is the second person to die from the virus amid a growing outbreak along the New Mexico-Texas border, sparking widespread concern among doctors that the federal government’s response is simply not enough to halt the spread of measles.

A measles outbreak in the American southwest has killed a second person, an unvaccinated adult, New Mexico health officials have said. The fatality comes roughly a week after measles took the life of an unvaccinated child in nearby Texas,

An unvaccinated New Mexico man tested positive for measles after death, becoming what health officials say could be the second death reported in the ongoing outbreak that has infected over 160 people in at least nine states.

An unvaccinated New Mexico resident tested positive for measles upon undergoing a medical examination after dying, but measles so far has not been declared the cause of death.