Arizona's count of presumed positive and confirmed new coronavirus cases remains at six, but testing for the virus is increasing.

As of Tuesday morning, the state had tested 84 people for the virus, which means 28 additional tests were done in the past day.

Fifty-one of the Arizona tests have come back negative and the results of 27 tests are pending, up from seven on Monday.

Six cases have been either confirmed or presumed positive — one in Pima County, two in Maricopa County and three in Pinal County.

On Friday, Pinal County officials announced that a health care worker in her 40s who lives in Pinal County and works in Maricopa County had tested positive for new coronavirus, which is officially called COVID-19. She is hospitalized but is in stable condition and expected to be discharged this week.

The woman had not traveled to any area affected by COVID-19 and had no known contact with an infected person. Public health officials don't know how she contracted the virus, which is why her case is considered the first instance of "community spread" in Arizona — a troubling development for officials trying to contain the virus.

Gov. Doug Ducey and Arizona Department of Health Services Director Dr. Cara Christ on Monday cautioned those at high risk for COVID-19 to stay away from crowds, reconsider travel plans and stock up on medications, groceries and other supplies.

The novel virus causes coughing, fever, shortness of breath. Though most people who contract the virus will have mild symptoms, it can result in pneumonia and, in some cases, death. People who are elderly and have underlying health conditions are considered high risk.

Right now public health officials are focused on testing people who have traveled to areas affected by COVID-19; those who have had known contact with an infected person; and people who are hospitalized with respiratory infections of no known cause. The testing guidelines could change depending on how the spread of disease evolves.

Reach health care reporter Stephanie Innes at Stephanie.Innes@gannett.com or at 602-444-8369. Follow her on Twitter @stephanieinnes

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