How Worried Should We Be About Lassa Fever?

May 26, 2015
Originally published on May 26, 2015 6:31 pm

An unidentified New Jersey man died after returning home from West Africa, where he had contracted Lassa fever, a virus that has symptoms similar to those of Ebola. Federal health officials are treating the case with caution because the virus, which commonly is spread by rodents, can occasionally spread from person to person.

Lassa fever can cause internal bleeding. Other symptoms include respiratory distress, vomiting, facial swelling, and back and abdominal pain. Dr. Tom Frieden, who heads the Centers for Disease Control and Prevention, says the virus is not nearly as deadly as Ebola. Ninety-nine percent of people with Lassa fever survive.

"It's not that rare a disease in West Africa," says Frieden. "One in six hospitalized patients may have Lassa."

The virus hardly ever makes its way to the United States. But it did on May 17, when a man returning from Liberia by way of Morocco landed at John F. Kennedy International Airport in New York. He fell ill a few days later and went to a hospital in New Jersey.

Frieden says the patient was sent home. A few days later he returned to the hospital feeling worse. Initially, Frieden says, the patient was asked if he'd been to West Africa and he said no.

Doctors later learned the man had traveled to Liberia. According to Frieden, he was a frequent visitor because he worked in the mining industry. So they suspected he might have Lassa fever and sent him to an isolation facility that had been equipped to assess patients who might have Ebola.

By Monday morning, the CDC had run tests that confirmed that the man had Lassa fever, not Ebola. That night he died of the disease.

The CDC is now helping state and local health officials track people who may have come into contact with the man's blood or secretions and keep an eye on them for 21 days as a precaution. The likelihood that he spread Lassa fever is "low at this point," says Frieden, "but it's not zero."

Yet in this age of global travel, there are no sure things. "That's why it's so important to strengthen our infection control in this country," says Frieden, "and our efforts around the world to find, stop and prevent health threats from spreading."

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A New Jersey man has died after returning home from West Africa. He contracted a virus while he was traveling, but it was not Ebola. NPR's Richard Harris reports, the CDC is treating the case with caution.

RICHARD HARRIS, BYLINE: Health officials say the unidentified man had a case of Lassa fever, which can cause internal bleeding and other symptoms that are similar to those of Ebola. Tom Frieden, who heads the Centers for Disease Control and Prevention, says fortunately it's not nearly as deadly as Ebola. Ninety-nine percent of people with Lassa fever survive.

TOM FRIEDEN, BYLINE: It's not that rare a disease in West Africa, where it can be endemic. And in the most affected areas, 1 in 6 hospitalized patients with fever may have Lassa.

HARRIS: The disease occurs in remote areas so it rarely makes its way to the United States, but it did on May 17, when a man returning from Liberia by way of Morocco landed at JFK Airport. He fell ill a few days later and went to a local hospital in New Jersey.

FRIEDEN: According to the hospital, he was asked whether he had been in West Africa and said no.

HARRIS: So Dr. Frieden says he was sent home, but a few days later, he returned to the hospital feeling worse. At that point, doctors learned the man had traveled to Liberia, and they suspected he might have Lassa fever, so they sent him to an isolation facility.

FRIEDEN: That was a hospital equipped to assess patients who might have Ebola.

HARRIS: By Monday morning, the CDC had run tests to confirm that the man had Lassa fever, not Ebola. And Monday night, he died of the disease. The CDC is now helping state and local health officials track people who may have come into contact with the man's blood or secretions.

FRIEDEN: We think that the likelihood that anyone could have become infected is low at this point, but it's not zero.

HARRIS: So health officials will keep an eye on people who came in contact with the man for 21 days, as a precaution. Richard Harris, NPR News. Transcript provided by NPR, Copyright NPR.