California on Wednesday became the latest state to order a 21-day quarantine for travelers who have been in close contact with Ebola patients.

In an attempt to avoid the criticism lodged against New York, New Jersey and Maine that had blanket quarantine orders, however, California will allow county health agencies to impose the quarantine on a case-by-case basis.

By working with county health departments to assess the individual risks, the California Department of Public Health said it “respects the individual circumstances of each traveler while protecting and preserving the public health.”

Quarantine can range from observation and monitoring to the “limitation on his or her freedom of movement.”

In the Bay Area, a Stanford doctor who returned last week from Liberia where he was treating Ebola patients was already being monitored by the San Mateo County Department of Public Health. The department coordinated with the CDC and San Francisco International Airport when Dr. Colin Bucks arrived late last week. He had no symptoms of the disease and came to an agreement with health officials to avoid contact with others but can leave the house for limited activities, such as jogging alone.

“We are very proud of the work this physician has done,” said Dr. Scott Morrow, San Mateo County’s health officer. “Healthcare workers who take care of patients with Ebola are not only helping those affected in West Africa, but also protecting people around the world, including here in the United States, by fighting the outbreak at its source.”

In Maine, a nurse who treated Ebola patients in West Africa and was quarantined in a New Jersey hospital tent against her will for three days said Wednesday that she will defy an order by Maine officials to isolate herself in her home for 21 days.

“I don’t plan on sticking to the guidelines,” Kaci Hickox told Matt Lauer on NBC’s Today Show on Wednesday. “I remain appalled by these home quarantine policies that have been forced upon me.”

On Tuesday, President Barack Obama said that while he was anxious to contain the disease, “we don’t want to discourage our health care workers from going to the front lines. They are doing God’s work over there, and they are doing it to keep us safe.”

On Wednesday, Defense Secretary Chuck Hagel issued an order that all American troops returning from the Ebola zone in West Africa must spend 21 days in isolation.

No cases of Ebola have been reported in California, but State Health Officer Ron Chapman said in a statement Wednesday that he was taking action to prevent any potential spread of the disease in the state. The order applies to anyone traveling to California who has come from an Ebola-affected area, including Liberia, Guinea and Sierra Leone, and has had close contact with an Ebola patient.

The state agency also alluded to travelers whose exposure to Ebola might not be as intense and gives leeway to counties to determine whether or how they should be quarantined.

While many health care workers have “selflessly volunteered to help combat” the epidemic, the news release says, some may have been involved in education efforts only and have had less exposure than others. “Some of these activities result in high-risk exposure with confirmed Ebola patients, while other activities involve no such exposure,” the statement said.

And when it comes to average travelers who are not health care workers, “Many of these traveler have had no exposure to confirmed Ebola patients, while other may have some uncertain level of exposure.”

The deadly virus can spread by direct contact with the blood or body fluids and contact with objects, like needles and syringes, that have been contaminated by Ebola. Health care workers in West Africa wear hazardous materials suits while treating patients. Experts say newly infected people pose little risk, but the sicker you get, the more virus you spread.

“In order to protect or preserve the public health, this order requires quarantine for individuals at risk of contracting and spreading Ebola and establishes statewide protocol to assess the risk of these travelers arriving in California in order to develop tailored quarantine orders based on the level of risk presented by each case,” the state health department said in a statement.

Contact Julia Prodis Sulek at 408-278-3409. Follow her at twitter.com/juliasulek