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WASHINGTON — More than 400 long-term care facilities nationwide now have residents who are infected with the coronavirus, an increase of 172 percent from 146 on March 23, according to the Centers for Disease Control and Prevention.

Signs from multiple states point to a rapid increase in cases in nursing homes and other long-term care facilities.

On Friday, a Washington state official told NBC News that 53 facilities had reported cases. New Jersey health officials announced Monday that 70 homes had cases. In New York, it's 155, according to the state Health Department. Los Angeles County's public health director announced Monday that the county had cases in 11 nursing homes.

In other words, just those four jurisdictions, which make up one-seventh of the national population, account for nearly reported 300 cases, even though the CDC's official total of 400-plus is for all 50 states.

And the number of cases in each home keeps rising. In Maryland, state officials say, one nursing home has more than 60 cases.

While some state and local facilities have provided the numbers of cases in nursing homes, federal and state officials are tight-lipped about naming the facilities.

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A CDC spokesperson declined to name the facilities, saying the agency does not collect the names. The CDC also did not provide a total number of infected residents in the 400-plus homes.

A spokesperson for the New York State Department of Health cited patient confidentiality in saying the agency would not name the 155 facilities statewide.

Reporters in Colorado and Rhode Island have had to submit open records requests to get lists of facilities with ongoing cases.

Said Toby Edelman, a senior policy attorney with the Center for Medicare Advocacy, a non-profit that promotes health-care access for the elderly, "Nursing home residents are at tremendous risk of getting COVID-19 because they are usually quite elderly and medically compromised."

"The public needs to know which facilities have active cases of coronavirus. Keeping this information secret adds to the tremendous anxiety that families already feel."

Nursing homes are required by the federal government to notify a sick resident's family of an illness. They are not required to provide notification to relatives of other residents, according to the New York Health Department.

The Centers for Medicare and Medicaid Services did not respond to a request for comment about notification guidance to facilities.

Some families with loved ones in nursing homes say they have not received timely updates from the facilities themselves.

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"I wish I could count on their communication, but now I'm going to the news for information rather than the facility," said Niki Smith, a resident of Nashville, Tennessee, whose father is in Gallatin Center for Rehabilitation and Healing, a nursing home where more than 100 cases have been reported.

Smith said she learned of the cases when her brother called to say he had read about them on Facebook, as first reported by NBC affiliate WSMV.

CareRite, the New Jersey-based company that owns Gallatin, did not respond to a request for comment.

"We've encouraged facilities and family members to make sure they have the most updated emergency contact information, and we encourage facilities to continue to keep loved ones updated about residents and the entire facility," said a spokesperson for the American Health Care Association, a long-term care industry trade group. "Each facility may have different ways they do that, so we have not given exact direction on how they implement that process."