The death toll from China's virus epidemic neared 1,400 on Friday with six medical workers among the victims, underscoring the country's struggle to contain a deepening health crisis.

Nearly 64,000 people are now recorded as having fallen ill from the virus in China, with officials revealing that 1,716 health workers had been infected as of Tuesday.

The grim figure comes a week after an outpouring of grief and public anger over the death of a whistleblowing doctor who had been reprimanded and silenced by police after raising the alarm about the virus in December.

The scale of the epidemic swelled this week after authorities in central Hubei province, the epicenter of the contagion, changed their criteria to count the number of cases, adding thousands of new patients to their tally.

The health emergency in China has caused fears of more global contagion, with more than two-dozen countries reporting hundreds of cases among them.

Three people have died outside mainland China.

The majority of cases of infections among health workers was in Hubei's capital, Wuhan, where many have lacked proper masks and gear to protect themselves in hospitals dealing with a deluge of patients.

Some 80,000 medical workers were involved in combatting the epidemic in Wuhan, the city government said earlier this month.

Under criticism over the handling of the crisis, China's Communist Party sacked two top-ranking officials in Hubei, and replaced them with senior cadres with security backgrounds.