When a St. Louis area woman called her county’s coronavirus hotline Thursday to report that she was experiencing symptoms, health officials told her family that they should all self-quarantine at home, they say. Her father took his other daughter to a school gala two days later.

The pair arrived Saturday at Villa Duchesne’s father-daughter dinner-dance, a formal affair at a Ritz-Carlton open to roughly 274 middle and high school girls and their guests. The man learned while he was there that the test results of the daughter with the symptoms indicated that she had a presumptive case of the novel coronavirus, and he and his other daughter left the event, school officials said in an email circulating on social media.

The upscale Catholic school in St. Louis and its sibling school, Oak Hill, canceled classes and activities Monday “out of an abundance of caution” because of dance attendees’ potential exposure to the contagious virus. Administrators then announced that the schools would remain closed through the week and would conduct a hospital-grade cleaning.

“We will use the day to gather information and guidance from health officials,” school administrators wrote to parents Sunday. “Our priority is our students and we want to mitigate any risk within our community.”

An attorney for the family, Neil Bruntrager, rebutted the county’s version of events. In phone calls and text messages before the symptomatic daughter received a diagnosis, county officials did not instruct the family to self-quarantine, Bruntrager said in an interview.

After officials informed the family Friday that they were arranging for a coronavirus test, the family’s doctor told the family that “my gut says you don’t have the virus,” Bruntrager said. He said the ill daughter, an Indiana University student who was studying in Milan, has mild symptoms and is recovering at home.

While some community members claimed that the family disregarded a quarantine request out of a lack of concern for others, Bruntrager said their assumptions were false and highlighted their serious concern about the virus.

“When people heard that they ‘broke the quarantine,’ people went berserk,” he said. “The panic just became abundantly clear.”

St. Louis County Executive Sam Page reiterated at a news conference Monday that he believed county health officials had told the family to self-quarantine and said this was the first time someone had indicated they did not understand those instructions.

Disparaging remarks made against the family on social media prompted police to patrol the family’s home, Page said. (Bruntrager said he was unaware of a police patrol.) Page repeatedly urged the community to move forward and use the opportunity to learn the seriousness of self-quarantine requests.

“There was certainly a lapse in judgment here, but it’s done,” Page said.

Community members expressed outrage on Facebook at the possibility that the patient’s father ignored officials’ direction to self-quarantine, and some suggested that the man should face legal consequences.

Jenny Koziatek Benz, whose nieces attended the dance with their father, said in an interview that she was “furious” and concerned for her 81-year-old mother, who lives across the street from her nieces.

“This is absolutely unacceptable,” said Benz, of Denver. “What kind of person would do something like that?”

The intense reaction underscores the resulting anger when someone reportedly disregards instructions to voluntarily stay home, as well as broader global anxiety about the virus that has infected more than 100,000 people around the world. The Missouri incident parallels a situation in which New Hampshire’s first coronavirus patient ignored direction to self-isolate and is believed to have infected another person.

In addition to attending the father-daughter dance, the Missouri man visited Deer Creek Coffee in Ladue on Saturday morning, the St. Louis Post-Dispatch reported. The coffee shop’s employees alerted the health department and then scrubbed the cafe.

“Disinfectant and bleach, a thorough cleaning,” owner Kent McCarty told the Post-Dispatch. “There is no cleaner surface right now than at Deer Creek Coffee. I can promise you that.”

Page, the county executive, told reporters Sunday that health officials had assumed “common sense and goodwill toward the community” would keep at home the family of the state’s first coronavirus patient, a woman in her 20s who recently traveled to Italy. The family expressed agreement with repeated requests to self-quarantine, Page said.

By all accounts, the patient complied with the direction. Her father and sister, however, violated the main point of a quarantine — staying away from other people.

“The county health directors informed him today that he must remain in his home, or they will issue a formal quarantine that will require him and the rest of his family to stay in their home by the force of law,” Page said Sunday.

Thousands of people across the country have been asked to self-quarantine since the coronavirus was first reported in the United States in January. Whether it comes from a person’s doctor or from health officials, a request to self-quarantine is voluntary and lacks legal force, said Wendy Parmet, a health policy and law professor at Northeastern University.

A person theoretically could be held civilly or criminally liable for transmitting the virus after disregarding a self-quarantine request, but Parmet said those consequences are unlikely. A lawsuit would have to show the infected person caused someone else’s illness and failed to take reasonable care. She also said criminal prosecution would be a bad way to make public health policy.

State officials, local officials or both in each state also have the power to issue quarantine orders, which are legally compulsory and carry a variety of consequences if violated. Some agencies need a judge to sign off on a quarantine order for it to last beyond a short period of time, Parmet said. Other agencies require the subject of the order to challenge it if they think it’s unwarranted.

The U.S. Department of Health and Human Services, the parent agency of the Centers for Disease Control and Prevention, has broad authority to quarantine people “reasonably believed” to have been exposed to communicable diseases. A person who wants to challenge a CDC quarantine has to request an internal review or take the case to court.

In the strictest scenario, Parmet said, police can enforce legally binding quarantine orders. An in-between scenario exists in which government officials threaten to file a legally binding quarantine order but have not done so.

To get people to comply with self-quarantine requests before legal orders come into play, officials should streamline their messaging about the virus and the purpose of staying away from other people, Parmet said.

“People are hearing that it’s just a cold, or it’s a hoax, or you can’t get tested anyway,” she said. “And then people are being sort of scapegoated for being the one who’s out.”