Dozens of employees at the Centers for Disease Control and Prevention — including “disease detectives,” high-ranking scientists and the entire Washington office — were notified late Friday that they were losing their jobs as part of the Trump administration’s latest round of federal layoffs.

It was unclear on Friday how many C.D.C. workers were affected. But it was the latest blow to an agency that has been wracked by mass resignations, a shooting at its Atlanta headquarters in August and the firing of its director under pressure from Health Secretary Robert F. Kennedy Jr.

Layoff notices landed in the email inboxes of C.D.C. employees shortly before 9 p.m. Eastern time on Friday, notifying employees that their duties had been deemed unnecessary or “virtually identical” to those being performed elsewhere in the agency. Scientists, including leaders, in offices addressing respiratory diseases, chronic diseases, injury prevention and global health were among those affected.

The staff of the Morbidity and Mortality Weekly Report, the journal that reports on health trends and emerging infectious threats, was also laid off. The publication’s storied history includes a June 1981 report that five previously healthy gay men were treated for an unusual pneumonia — the first hint of the AIDS epidemic.

Roughly 70 Epidemic Intelligence Service officers — the so-called “disease detectives” who respond to outbreaks around the globe — received layoff notices, according to a person familiar with them. The service was spared during an earlier round of layoffs in February.