This photo taken on January 24, 2020 and released by China's Xinhua News Agency shows chief nurse Ma Jing (R) holding a patient's hand to comfort her in the ICU (intensive care unit) of Zhongnan Hospital of Wuhan University in Wuhan

Forty health care workers were infected with the novel coronavirus by patients at a single Wuhan hospital in January, a new study has found, underscoring the risks to those at the frontlines of the growing epidemic.

One patient who was admitted to the surgical department was presumed to have infected 10 health care workers, according to the paper that was authored by doctors at the Zhongnan Hospital of Wuhan University and published in the Journal of the American Medical Association (JAMA) on Friday.

Seventeen patients who were hospitalized for other reasons also became infected by the coronavirus. A total of 138 patients got the virus in a period spanning January 1 to January 28, with hospital-associated transmission accounting for 41 percent of all cases.

The study comes just hours after a Chinese doctor who was punished for raising the alarm about the coronavirus died from the pathogen -- sparking an outpouring of grief and anger over a worsening crisis that has now killed more than 630 people.

Li Wenliang, 34, sent out a message about the new coronavirus to colleagues on December 30 in Wuhan but was later among a group of people summoned by police for "rumor-mongering."

He later contracted the disease while treating a patient.

Of the 40 infected health care workers in the JAMA study, 31 worked on general wards, seven in the emergency department, and two in the ICU.

The example of the patient presumed to have infected 10 health workers highlighted the high level of danger within hospitals during the first phase of the epidemic, even though overall it is currently estimated that each patient infects on average 2.2 others.

"If true, then this confirms that some patients are likely to be far more infectious than others, and this poses further difficulties in managing their cases," said Michael Head, a global health expert at the University of Southampton said in a comment to the UK's Science Media Centre.

Medical staff at the epicenter of the virus are overstretched and lack sufficient protective gear, the deputy governor of Hubei province admitted Thursday.