Separately, the state’s health officer, Dr. Kathy Lofy, said in an interview that officials have started investigating a few other individuals in the state to determine whether they may have the coronavirus strain.

While assuring the public that there was little threat, officials have said the patient in Washington State would most likely not be the last Wuhan coronavirus case to reach the United States. Dr. Lofy encouraged people to take typical steps that could prevent the spread of illnesses, such as washing hands and avoiding touching their eyes, nose and mouth.

“Currently, we believe the risk to the general public is low,” Dr. Lofy said.

The strain of coronavirus surfaced in December and has spread through parts of Asia, sickening hundreds and killing at least 17 people. The authorities in China have since closed off Wuhan, a city of more than 11 million people, by canceling flights and trains leaving the city, and suspending bus, subway and ferry service within it. Travel restrictions have been extended to several cities nearby.

The United States has put travel limits of its own in place, funneling passengers who have traveled recently to Wuhan through a handful of airports, including Los Angeles International, that have special screening processes in place.

A passenger who arrived at Los Angeles International on an American Airlines flight from Mexico City on Wednesday night was taken to a hospital for a “precautionary medical evaluation,” officials said. Heath Montgomery, an airport spokesman, said he did not know whether the traveler had recently been to China or whether coronavirus was suspected.