FORT KENT, Maine — A nurse who vowed to defy Maine’s voluntary quarantine for health care workers who treated Ebola patients followed through on her promise Thursday, leaving her home for a bike ride.

Kaci Hickox and her boyfriend stepped out of their home Thursday morning and rode away on bicycles, followed by state police who were monitoring her movements and public interactions. Police couldn’t detain her without a court order signed by a judge.

Hickox contends there’s no need for quarantine because she’s showing no symptoms. She’s also tested negative for the deadly disease.

State officials were going to court in an effort to detain Hickox for the remainder of the 21-day incubation period for Ebola that ends on Nov. 10

It was the second time Hickox broke quarantine. She left her home Wednesday evening briefly to speak to reporters, even shaking a hand that was offered to her.

“There’s a lot of misinformation about how Ebola is transmitted, and I can understand why people are frightened. But their fear is not based on medical facts,” Norman Siegel, one of her attorneys, said Wednesday.

Hickox, who volunteered in Sierra Leone with Doctors Without Borders, was the first person forced into New Jersey’s mandatory quarantine for people arriving at the Newark airport from three West African countries. Hickox spent the weekend in a tent in New Jersey before traveling to the home she shares with her boyfriend, a nursing student at the University of Maine at Fort Kent.

“I’m not willing to stand here and let my civil rights be violated when it’s not science-based,” she told reporters Wednesday evening.

Generally, states have broad authority when it comes to such matters. But Maine health officials could have a tough time convincing a judge that Hickox poses a threat, said attorney Jackie L. Caynon III, who specializes in health law in Worcester, Massachusetts.

“If somebody isn’t showing signs of the infection, then it’s kind of hard to say someone should be under mandatory quarantine,” he said.

Ebola, which is spread through direct contact with the bodily fluids of an infected person, has killed thousands of people in Africa, but only four people have been diagnosed with it in the United States. People can’t be infected just by being near someone who’s sick, and people aren’t contagious unless they’re sick, health officials say.

Guidelines from the federal Centers for Disease Control and Prevention recommend daily monitoring for health care workers like Hickox who have come into contact with Ebola patients. But some states like Maine are going above and beyond those guidelines.

The defense department is going even further. On Wednesday, Defense Secretary Chuck Hagel ordered military men and women helping fight Ebola to undergo 21-day quarantines that start upon their return — instead of their last exposure to an Ebola patient.

President Barack Obama warned that overly restrictive measures imposed upon returning health care workers could discourage them from volunteering in Africa.

But Maine Gov. Paul LePage, who canceled campaign events to keep tabs on the situation, maintained that the state must be “vigilant” to protect others.

State law allows a judge to grant temporary custody of someone if health officials demonstrate “a clear and immediate public health threat.”

The state’s court filing was expected Thursday, officials said.

If a judge grants the state request, then Hickox will appeal the decision on constitutional grounds, necessitating a hearing, Siegel said.

Siegel said the nurse hopes her fight against the quarantine will help bring an end to misinformation about how the Ebola virus is transmitted.

“She wants to have her voice in the debate about how America handles the Ebola crisis. She has an important voice and perspective,” he said.