Three people in Iowa tested presumptively positive for the novel coronavirus, Gov. Kim Reynolds announced Sunday night, marking the first time the virus has been detected in the state.

The three people who live in Johnson County tested positive for the virus after returning March 3 from a cruise that traveled through Egypt, Reynolds told reporters at an evening news conference.

"While this news is concerning, it's not cause for alarm," Reynolds said from the Capitol. "The most important thing that we can do right now is to remain calm, understand the situation and stay informed in the days and weeks ahead."

State officials, for now, said Iowans do not need to take additional or special precautions other than routine advice, recommending residents continue to wash their hands with soap and water, cover their coughs and sneezes and stay home when sick.

► More:Coronavirus is here in Iowa. What does that mean for you?

"We're still in the early stages of gathering all the information necessary to fully assess the situation and prepare for the next steps," Reynolds said while surrounded by officials from the Department of Public Health, the Iowa Department of Homeland Security and the Iowa National Guard. "As soon as we know more, you'll know more."

The cases in Iowa are considered presumptive until the Centers for Disease Control and Prevention confirms the test results.

The three were on a cruise

The cruise that the three Iowans were on ran from Feb. 17 to March 2, according to Gerd Clabaugh, director of the Iowa Department of Public Health. All three returned to their residences on March 3. They later sought health care services after feeling ill and were sent home.

"The three are currently isolated in their homes," Clabaugh said. "Public health and health care partners are doing what they're trained and equipped to do to protect patients, themselves and the community."

Officials described one of the individuals who tested positive as middle-aged, between 41 and 60 years old, and the two others as older, between 61 and 80 years old. They said two had underlying health conditions and one did not.

COVID-19, the respiratory disease caused by the virus, has been spreading around the world. Reported cases in the United States have accelerated in recent days as more testing becomes available.

The public health department in Iowa has tested multiple people for the virus as of Sunday, according to a tally it keeps on its website. Officials began testing for the virus here just over a month ago. On Feb. 5, the department announced two people who had traveled to China were in voluntary home confinement amid testing. They later tested negative for the virus.

► More:More people in Iowa test negative for coronavirus; Reynolds taps emergency center. Here's the latest on what you need to know

Testing continues for others

The State Hygienic Laboratory at the University of Iowa said Friday that it has materials to test about 500 people. As of Sunday, the lab had tested just 37, according to state officials. Three have tested positive, 26 have tested negative and there are now 8 pending tests.

More: Is your kid vying for 'perfect attendance?' Some schools suspend challenge as COVID-19 spreads

People in Iowa cannot request to be tested for the coronavirus at this point, according to Polly Carver-Kimm, a spokeswoman at the Iowa Department of Public Health. Instead, health care providers following guidelines around a person's symptoms must contact the department.

Officials in Iowa have said for weeks that the risk of contracting the virus in the state is low, in part because many of the early reported cases were linked to international travel in areas with large outbreaks.

But some of the cases now reported around the U.S. do not have clear links to that kind of travel, a potential sign that infection could spread through a community.

State officials in Iowa have been preparing for the virus in part by offering safety guidelines to health providers, educators, employers and the public. On Saturday, Reynolds announced she had ordered partial activation of a state emergency operations center that allows state agencies to work more closely. She said Sunday the center is now completely activated.

As Iowans learned of the first presumptive cases of COVID-19 in the state, the U.S. State Department on Sunday warned travelers with underlying health conditions to avoid travel by cruise ship.

"CDC notes that older adults and travelers with underlying health issues should avoid situations that put them at increased risk for more severe disease," the State Department said in a statement. "This entails avoiding crowded places, avoiding nonessential travel such as long plane trips, and especially avoiding embarking on cruise ships."

In addition to an increased risk of infection on cruise ships, passengers have undergone strict screening procedures, have been denied entry at ports, or have been subjected to local quarantines when docking was permitted.

Three Maryland residents tested positive Thursday for the coronavirus after traveling on an Egyptian cruise on the Nile River, Maryland Gov. Larry Hogan said Friday evening. It is unclear if that cruise was the same as the one the Iowans were on.

► More:Iowa biotech firm says it has produced enough coronavirus tests for 700,000 patients

Barbara Rodriguez covers health care and politics for the Register. She can be reached by email at bcrodriguez@registermedia.com or by phone at 515-284-8011. Follow her on Twitter @bcrodriguez.

This content is being provided for free as a public service to our readers during the coronavirus outbreak. Please support local journalism by subscribing to the Des Moines Register at DesMoinesRegister.com/Deal.