A nursing home in Washington state is being closely monitored after five residents and a staff member tested positive for the coronavirus, one man died and more than 50 others showed respiratory symptoms, according to state health officials.

The first coronavirus death in the US was confirmed in Washington state on Saturday.

The second death was a man in his 70s with an underlying health condition who died at the nursing home.

The other cases include a woman in her 80s, a woman in her 90s and a man in his 70s. All three have underlying health conditions, and were reportedly in “critical condition.”

The US has confirmed approximately 60 cases of the severe respiratory illness. The World Health Organization has reported that 85,000 people have been sickened and more than 2,800 have died worldwide. The vast majority of cases have been in China but the virus is spreading, seriously affecting international travel, business and sporting and cultural events.

Most coronavirus infections result in mild symptoms but some can lead to pneumonia. Older people, especially those with chronic illnesses, are vulnerable. Officials think the virus spreads mainly through coughs or sneezes.

The Washington state nursing home, Life Care Center of Kirkland, has about 108 residents and 180 staff members. Officials reported that about 27 residents and 25 staff members had respiratory symptoms or had been hospitalized with respiratory conditions including pneumonia and were being tested for coronavirus. It was not immediately clear when those test results would be released.

We are very concerned about an outbreak in a setting where there are many older people Dr Jeff Duchin

The cases confirmed include a woman in her 40s who worked at the center and was in “satisfactory condition” as of Saturday. A woman in her 70s, a resident, was reported in serious condition.

The Life Care Center announced it would not allow visits from families, volunteers or vendors and was putting a hold on admissions.

Ellie Basham, the executive director, said in a statement on Sunday any residents with symptoms were in isolation and all associates must be screened before work. If they have symptoms they are sent home.

“We are following the infection control recommendations from the [federal Centers for Disease Control and Prevention], including proper hand-washing techniques and wearing masks, gowns and gloves when caring for any symptomatic patients,” Basham said.

Dr Jeff Duchin, health officer for Seattle and King county, said on Saturday officials were investigating the situation at the facility and “would not be surprised to find additional cases”.

A team of about 10 officials from the CDC traveled to Washington state to work with local health experts.

“We are very concerned about an outbreak in a setting where there are many older people, as we would be wherever people who are susceptible might be gathering,” said Duchin.

More than two dozen firefighters and police officers in Kirkland who have responded to calls at the Life Care Center over the last few weeks have been placed under quarantine, according to the city government. They are either at home or at a fire station.

“None of them are presenting any symptoms and we hope they will be tested and cleared soon,” city manager Kurt Triplett said.

A group of about 16 nursing students and one faculty member from the Lake Washington Institute of Technology visited the Life Care Center late last week, Dr Amy Morrison, president of the college, said in a statement. As of Saturday evening, school officials were awaiting instructions from public health officials.

“The safety of our students, faculty and staff is our priority, so as a precautionary measure, we are disinfecting the college campus tomorrow,” Morrison said.

Over the last few days, local officials reported four coronavirus cases in King county, which includes Seattle, including the man in his 50s who died. The patient, who was not immediately identified, was the first reported US death associated with the coronavirus. He was chronically ill and had no history of travel to affected areas or contact with a known Covid-19 case, officials said.

Health officials said on Saturday they did not see any connection between the man who died and the nursing facility, but they were still investigating how those patients contracted the virus.

On Sunday, state health officials reported two new cases in King county. A man in his 60s with underlying health conditions was reported to be in “critical but stable condition” while another man in his 60s, also with underlying health conditions, was in critical condition.

One unidentified Washington state patient reportedly works for the US Postal Service. According to Kiro 7, a local news station, the man worked at a Seattle Network Distribution Center and no mail was sent out from the facility.

Governor Jay Inslee declared a state of emergency in response to the new cases, saying state agencies should use “all resources necessary to prepare for and respond to the outbreak”.

In January, Washington state reported the first case of coronavirus in the US when a man in his 30s was admitted to a hospital in Everett after returning from central China. He has since recovered.

As of Sunday, 12 people in Washington state had tested positive, officials said.