Story highlights The man didn't have a fever when he came back to the U.S. from Liberia last week

He died Monday evening after testing positive for Lassa fever, the CDC says

Officials say the risk to other people is considered "extremely low"

(CNN) A man who returned to New Jersey from West Africa has died of Lassa fever, a disease that's only known to have entered the United States a handful of times in the past few decades, authorities said.

The man didn't have a fever when he left Liberia on May 17, or upon arrival at JFK International Airport in New York, the Centers for Disease Control and Prevention said Monday.

The next day, he went to a New Jersey hospital complaining of a sore throat, fever and tiredness. But he didn't tell the staff there about his travel to West Africa and was sent home the same day, the CDC said.

He went back to the hospital Thursday with worsening symptoms and was moved to a treatment center for viral hemorrhagic fevers. A test for Lassa fever came back positive early Monday, according to the CDC. The patient died that evening in isolation.

"Lassa fever is a viral disease common in West Africa but rarely seen in the United States," the CDC said. "There has never been person-to-person transmission of Lassa fever documented in the United States."

Read More