A man who traveled from Liberia died in New Jersey over the weekend from Lassa fever, U.S. health officials said, adding that authorities are looking for people who had contact with him although the risk of infection is extremely low.
Lassa, a viral disease common in West Africa, is far less fatal and less contagious than the deadly Ebola virus that has raised global health concerns amid a large outbreak, according to the Centers for Disease Control.
The health agency said the man traveled on May 17 from Liberia to John F. Kennedy International Airport in New York with a stop in Morocco, and reported no symptoms and had no fever when he arrived in the United States.
The next day, however, the traveler went to a New Jersey hospital and reported a sore throat, fever and fatigue but did not report his travel from West Africa, the CDC said in a statement. It did not identify the hospital.
He was sent home but returned to the hospital three days later when his symptoms worsened, it said. The man, who has not been identified, died Monday night.
It was only the sixth known case of the virus in the United States since 1969, according to the CDC. "There has never been person-to-person transmission of Lassa fever documented in the United States," it said.
Still, the agency said it was working with public health officials to track down people who had contact with the man, and those who had close contact will be monitored for 21 days to see if they develop symptoms.
Unlike Ebola, which has a 70 percent fatality rate with no treatment, Lassa fever has a 1 percent fatality rate, the CDC said. "However, some Lassa patients develop severe disease, as the patient in New Jersey did," it said.
Travelers to the United States from West Africa have been screened for Ebola-like symptoms since a man with that virus who had traveled from Liberia died from the disease at a Texas hospital last year and two nurses were infected.
Liberia has since been declared Ebola-free, but cases continue to rise in nearby Guinea and Sierra Leone as global health officials and other countries remain concerned about the outbreak.