This undated electron microscope image made available by the U.S. National Institutes of Health in February 2020 shows the Novel Coronavirus SARS-CoV-2, orange, emerging from the surface of cells, green, cultured in the lab. Also known as 2019-nCoV, the virus causes COVID-19. The sample was isolated from a patient in the U.S. Courtesy photo ▲

An Omaha woman has the first confirmed case of the coronavirus in Nebraska.

The 36-year-old woman is believed to have contracted COVID-19 while traveling with her father in the United Kingdom from Feb. 18-27, according to Dr. Robert Penn, an epidemiologist at Methodist Hospital in Omaha.

Penn said the woman started developing symptoms Feb. 24, and that her illness remained mild until Thursday, when she was brought to Methodist Hospital and diagnosed with a pneumonia-like infection and low blood-oxygen levels.

Doctors put the woman into a negative-airflow room — similar to those available at the University of Nebraska Medical Center's biocontainment and quarantine units — and screened her for common community viruses.

Tests showed she was positive for COVID-19, Penn said, and chest scans showed she has pneumonia-like symptoms seen in other patients with the disease.

Friday afternoon, Penn said the woman is "very, seriously ill."

Meanwhile, the U.S. death toll from the coronavirus climbed to 14, with all but one victim in Washington state, while the number of infections swelled to more than 200, scattered across about half the states. Pennsylvania, Indiana and Minnesota also reported their first cases, according to The Associated Press.

Worldwide, the virus has infected more than 100,000 people and killed more than 3,400, the vast majority of them in China. Most cases have been mild, and more than half of those infected have recovered.

Working in conjunction with UNMC, the woman in Omaha who tested positive was moved from Methodist to the Nebraska Biocontainment Unit, where she will join an existing patient exposed to the novel coronavirus on the Diamond Princess cruise ship and brought to Omaha for treatment.

The transport plan included use of an isolation pod, according to Shelly Schwedhelm, a nurse and director of emergency management at UNMC, to protect health care workers and the public.

Late Friday, Nebraska Medicine said in a news release the woman had arrived at the biocontainment unit.

"We want to emphasize to the community that very few positive cases of the coronavirus will be treated in the Nebraska Biocontainment Unit," Nebraska Medicine said. "That unit has a 10-patient capacity and is reserved for only the most severe cases of the virus, or for use during incidents like the one involving the Diamond Princess cruise ship."

There are other areas within the hospital where coronavirus patients can be safely treated, the statement added.

The state epidemiologist was expected to arrive at Methodist on Friday and begin tracing any contacts the woman may have had since returning to Omaha on Feb. 27.

Nebraska's Chief Medical Director Gary Anthone said it was too early to tell the extent of those contacts.

"We don't know those answers right now, I'm afraid," Anthone said. "I think it would be better if it were only a few days rather than a number of days, but that is something we'll have to see."

Gov. Pete Ricketts, who led the Friday afternoon conference call when the news was announced, added: "We don't want to speculate on that until we have the facts."

People who have been in close contact with the woman will be asked to "self-isolate," the governor's office said in a news release. They will be monitored twice daily by public health officials for fever and respiratory systems, and if they start experiencing symptoms, they will immediately undergo further testing.

The governor said Nebraska has the capability to screen the people who may have come into contact with the infected woman, and is working with the White House and UNMC to expand its capacity.

The Nebraska Department of Health and Human Services said Friday that five cases of possible coronavirus are undergoing further testing at the state's Public Health Lab. But state officials stressed that there is no evidence of COVID-19 spreading in Nebraska communities at this time.

There have been no confirmed cases of coronavirus in Lincoln, where Mayor Leirion Gaylor Baird said the Lincoln-Lancaster County Health Department is leading efforts to ensure there’s a coordinated response when needed.

Local physicians have begun changing their protocols to identify and prepare for patients who may have symptoms seen in patients with the disease, said Joan Anderson, the Lancaster County Medical Society executive director.

The health department conducted a training exercise with local health care providers earlier this week focused on preparedness and on sharing information, Interim Lincoln-Lancaster County Health Department Director Pat Lopez said.

Ricketts reminded Nebraskans to wash their hands frequently, resist touching their face, forgo shaking hands with others, avoid those who are sick and to routinely disinfect surfaces that come into regular contact with people as the best ways to prevent spread of the virus.

He also said individuals who are sick should remain home and encouraged businesses to work with their employees who may be ill.

Ricketts said to make sure you have two weeks' worth of food and medications and think through what you would do if schools and child care centers close or you have to work from home.