BEIJING — China reported a surge in deaths and infections from a new virus Thursday after changing the way the count is tallied, further clouding an epidemic that has stirred fear as it spread to more than two dozen countries.

The spike came after two days in which the number of new cases dropped and brought little clarity for those desperate to understand the trajectory of the outbreak.

“What we need is some consistency over time to give us an idea of what’s actually happening,” said Dr. William Schaffner, an infectious disease expert at Vanderbilt University in the United States. “Is transmission happening or is it not?”

The answer has proved frustratingly elusive despite the official reports.

The death toll in China from the disease known as COVID-19 reached 1,367, up 254 from a day earlier, and the number of confirmed cases jumped to 59,804, up 15,152.

Dr. Michael Ryan, the World Health Organization’s emergencies chief, said the dramatic increase was due to a revised way of counting cases and cautioned it did not represent a sudden surge in new infections.

“This increase you’ve all seen in the last 24 hours is largely down to how cases are being diagnosed and reported,” he said, noting that the jump in infections refers to patients that go back days and weeks, including to the beginning of the outbreak.

China’s National Health Commission said officials in Hubei province, whose stricken capital of Wuhan is the virus’ epicenter, began tallying cases using a lower bar of “clinical diagnosis.” That appears to count cases based on doctors’ analyses and lung imaging rather than relying solely on laboratory test results. More than 13,000 of the newly-reported infections were a result of the new way of counting.

A spokesman for China’s health commission, Mi Feng, said the change was aimed at identifying suspected cases in which the patient has pneumonia so they can be treated quicker and reduce the likelihood of more serious illness or death. It was also seen as a reflection of a chaotic crush of people seeking treatment and the struggle to keep up with a backlog of untested samples.

“Clearly in Wuhan, the health system is under extreme pressure and so the first priority has to be the patient,” said Mark Woolhouse, a professor of infectious disease epidemiology at the University of Edinburgh.

In further clues to the desperate attempt to contain the virus and public criticism of the government’s efforts, China replaced two more high-level officials — the ruling Communist Party chief in Hubei and the party secretary in Wuhan. Those followed the sacking earlier in the week of two leaders of the provincial health commission and reports from state media of a slew of others expelled from the party for missteps related to the epidemic.

The public has widely criticized local officials for failing to respond quickly and decisively to the new virus.