Story highlights The 2 cases are the first transmission from patients to health care workers

One person is in critical condition and the other is stable

So far, 40 cases of the new virus have been reported; 20 people have died

Two health care workers in Saudi Arabia were sickened while treating patients with a dangerous new virus, the World Health Organization said Wednesday.

The health care workers were exposed to patients with the novel coronavirus, or nCoV, the WHO said in a statement Wednesday. One is a 45-year-old man who is currently in critical condition after becoming ill May 2, and the second is a 43-year-old woman who became ill on May 8 and is in stable condition. The woman has a co-existing health condition, the organization said.

"Although health care associated transmission has been observed before with nCoV (in Jordan in April 2012), this is the first time health care workers have been diagnosed with nCoV infection after exposure to patients," according to the WHO.

"Health care facilities that provide care for patients with suspected nCoV infection should take appropriate measures to decrease the risk of transmission of the virus to other patients and health care workers."

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NCoV was recently found for the first time in humans, and cases have occurred across parts of the Middle East, particularly Saudi Arabia.

As of Wednesday, the organization said it had been informed of 40 laboratory-confirmed cases of human infection with nCoV worldwide since last September. Twenty people in six countries -- France, Germany, Jordan, Qatar, Saudi Arabia and the United Kingdom -- have died.

Coronaviruses, which are common around the world, often cause colds. The novel coronavirus is also in the same family as SARS.

NCoV acts like a cold and attacks the respiratory system, the Centers for Disease Control and Prevention has said. But symptoms are severe, and can lead to pneumonia and kidney failure.