Arizona's count of reported coronavirus cases went up to 21 on Tuesday after Navajo County announced its first two positive cases and Maricopa County announced two more positive cases.

Navajo officials say a 46-year-old member of the Navajo Nation from the community of Chilchinbeto, with recent travel history, tested positive for the COVID-19 coronavirus. It was the first confirmed case involving a member of the Navajo Nation.

Later Tuesday, Navajo President Jonathan Nez went on KTNN radio and announced the a second positive case from the Navajo Nation, a 40-year-old man who also had been traveling.

The Navajo County Public Health Department says it is working with the Navajo Nation to investigate the first case, as well as any close contacts who may have been exposed. As of late Tuesday, the county had not confirmed the second Navajo County case.

The two new Maricopa County cases:

A man in his 50s who is recovering in isolation at home.

A woman in her 60s who is hospitalized.

The Maricopa County Department of Public Health on Tuesday also announced that a man in his 90s who had previously been identified as a COVID-19 case has since been determined to be negative, and that his case will no longer be part of the positive case total.

The tally of cases in Arizona likely is much lower than the actual number of cases in the state.

So far, the state has reported nine presumptive positive or confirmed cases in Maricopa County; five in Pinal County; four in Pima County; and one in both Graham and Navajo counties. The state as of Tuesday had not reported the second Navajo County case.

Arizona has "community spread" of the new coronavirus, also known as COVID-19, meaning patients who have not traveled to an area affected by the new coronavirus and have not had known contact with an infected person are contracting the virus.

The Arizona Department of Health Services as of Tuesday began advising canceling or postponing gatherings of 10 or more people. The state issued the new guidance to reflect recent recommendations from the U.S. Centers for Disease Control and Prevention.

The state health department also announcedit was recommending dining establishments in areas of known community spread — Maricopa, Pima and Pinal counties — discourage dine-in traffic and instead provide outside pick up and drive-through services.

"Restaurants should establish protocols that allow food delivered to cars," the department said in a tweet. "If dine-in options are provided, social distancing measures should be implemented, providing space for customers to be placed at least six feet apart, and limiting space for customers to congregate in areas of the restaurant.

Governors in some states have ordered all bars and restaurants to close to stop the spread of COVID-19 infection, but Arizona Gov. Doug Ducey has not taken that step.

State data shows 221 people statewide have been tested so far, but that number does not include tests done in private labs. Two private, commercial labs began testing in Arizona last week. State data shows the results of 66 tests are pending.

Testing, which has been limited so far, is expected to further ramp up this week as more commercial labs enter the market. The state on Monday announced that test collection sites for any Arizonans with COVID-19 will be opening in Arizona soon and more details are expected this week.

Navajo Nation president: 'Just stay home'

"The best thing that we can do is just stay home," Navajo Nation President Jonathan Nez said Tuesday.

"It seems like the bug came from off the nation onto the nation," he said, because both cases on the Navajo Nation were the result of traveling.

"We tried to do our very best to keep the bug out of Navajo," Nez said, and he appreciates all the hard work his departments have done in the past three months.

Navajo Nation Vice President Myron Lizer said the Navajo Nation has been operating as business as usual while adopting some rigorous methods to help fight off the virus.

The Navajo Nation closed all schools, tribal parks and casinos in an effort to combat the virus. Navajo Nation government workers are working remotely or offices have reduced to essential staff.

He said he is hoping that the Navajo people take this time to spend with their families and children, and maybe even provide traditional or cultural teachings for the children who are home from school.

"Keep our young people's minds off this incident so it doesn't overwhelm them," Nez said. "We're encouraging people to look at it that way."

Cases will 'skyrocket,' Maricopa County health official predicts

In a letter to health providers dated Monday, Dr. Rebecca Sunenshine, who is medical director of the disease control division for Maricopa County Health Department, predicted new coronavirus cases in Arizona are about to "skyrocket."

"Not because there are more cases but because commercial test results are just starting to come back, and testing for people with mild to moderate symptoms is finally available," she wrote.

"These cases have been in the community for a while. Public Health is relying on a combination of surveillance methods to understand disease spread in the community — case counts are only one aspect of that surveillance."

The Arizona Poison and Drug Information Center is available to take COVID-19 calls from Arizona providers and the general public: 1-844-542-8201.

The Johns Hopkins University School of Medicine's COVID-19 Resource Center as of Tuesday listed the worldwide case count at 189,160, including 7,504 deaths. The site listed 5,145 cases in the U.S., including 84 deaths.

Republic reporter Shondiin Silversmith contributed to this article.

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

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