Iowa’s first three presumptive cases of COVID-19, the disease caused by the new coronavirus, have been detected in Johnson County, Gov. Kim Reynolds announced Sunday.

All three individuals were on a cruise in Egypt. Two of them are older adults between the ages of 61 and 80, and one is middle-aged, between the ages of 41 and 60. Reynolds said none of them required hospitalization, and they are “self-quarantined at home.”

Reynolds said the news is concerning, but it’s not cause for alarm.

“I want Iowans to know that I am confident we are prepared, that we take this situation seriously, and we will manage it responsibly,” Reynolds said. “I ask the same of every Iowan: the most important thing you can do is to stay informed, know the facts about the virus, how to prevent it, and what to do if you are sick.”

Reynold said the State Emergency Operations Center in Johnston is fully activated to coordinate a statewide response.

"If you don't feel well, stay home and away from others." - Iowa Department of Public Health Medical Director Dr. Caitlin Pedati

She also said Iowans with questions about COVID-19 can call a public hotline at 211.

The first cases are considered “presumptive” until the U.S. Centers for Disease Control and Prevention confirms Iowa’s tests.

Public health officials say they are still gathering information about who the three individuals came into contact with and what additional actions may need to be taken.

COVID-19 symptoms can include fever, cough and breathing trouble. Most people will only develop mild symptoms. But more vulnerable patients with other medical complications can develop pneumonia, which can be fatal.

Iowa Department of Public Health Medical Director Dr. Caitlin Pedati said Iowans should help prevent spreading illness by frequently washing their hands with soap and water for 20 seconds, staying home when sick, and covering coughs and sneezes.

“If you don’t feel well, stay home and away from others,” Dr. Pedati said. “Because we know this virus moves from one person to the next when we’re in close proximity to each other, and if we take away its ability to do that, then we limit the spread.”

She also said clinical staff who see patients with these symptoms and recent travel to places flagged by the IDPH should contact public health officials.

According to the Iowa Department of Public Health, 37 people have been tested for COVID-19 in Iowa. Twenty-six of those tests have come back negative, and eight are still pending.

The state had the materials to test about 500 people for COVID-19, and as of Sunday evening, 37 people had been tested.

State health officials have previously said the risk of the virus, which originated in Wuhan, China, is low for Iowans, but have asked those who have traveled abroad to affected areas to take extra precautions.

Last week officials requested that Iowans who have returned from China, Hong Kong, Iran, Italy, Japan and South Korea voluntarily "self-isolate" for 14 days by staying home from work and school and avoiding crowded public areas.

Some Iowa universities, including Iowa State University and Morningside College, have recalled students from study abroad programs in countries that have reported large outbreaks.

Since the end of February, the State Hygienic Laboratory in Iowa City has been able to test for the virus.

On Friday, health officials in Nebraska reported that state's first case in Omaha, a 36-year-old woman who became ill while travelling in the United Kingdom.

There have been 164 cases of COVID-19 in 19 states, according to the Centers for Disease Control and Prevention. Eleven people, mostly in the Seattle area, have died from the illness.

There have been more than 100,000 cases of the virus reported worldwide and more than 3,000 deaths.