PROVIDENCE, R.I. — Vilified, threatened with violence and in some cases suffering from burnout, dozens of state and local public health leaders around the U.S. have resigned or have been fired amid the coronavirus outbreak, a testament to how politically combustible masks, lockdowns and infection data have become.

One of the latest departures came Sunday, when California’s public health director, Dr. Sonia Angell, quit without explanation following a technical glitch that caused a delay in reporting virus test results — information used to make decisions about reopening businesses and schools.

Last week, New York City’s health commissioner was replaced after months of friction with the Police Department and City Hall.

A review by the Kaiser Health News service and The Associated Press finds at least 49 state and local public health leaders have resigned, retired or been fired since April across 23 states. The list has grown by more than 20 people since the AP and KHN started keeping track in June.