An American man who returned home from a tour of Liberia last week died on Monday from the viral hemorrhagic disease Lassa fever at a New Jersey hospital.
The Centers for Disease Control and Prevention (CDC) and the New Jersey Department of Health confirmed in a press statement the death of the man from the disease, which is rare in the U.S. but common in West Africa,
The man took a flight from Liberia to John F. Kennedy International Airport in New York on May 17 with a stopover in Morocco, according to the CDC.
"The patient did not have a fever on departure from Liberia, did not report symptoms such as diarrhea, vomiting, or bleeding during the flight, and his temperature was taken on arrival in the U.S. and he did not have a fever at that time," the CDC said in a press statement.
The patient went to the hospital on May 18 complaining of sore throat, fever and tiredness. Hospital staff asked him where he traveled, but he did not say he returned from a trip to West Africa. The patient was sent home on the same day, only to return two days later because his symptoms worsened. He was transferred to a treatment center equipped to treat viral hemorrhagic fevers.
Samples of the patient's blood and body fluids were tested and the result that became available on Monday indicated he was negative from Ebola but positive from Lassa fever.
The CDC is tracing people who had contact with the patient so they would be monitored for 21 days to see if symptoms occur.
The CDC described Lassa fever as a rat-borne disease with some symptoms similar to Ebola. Like Ebola, Lassa fever can cause internal bleeding. But generally Lassa fever is less likely to be fatal than Ebola, with an approximately 1 percent fatality rate, and less likely to be spread from person to person. Ebola has an approximately 70 percent case fatality rate for patients who are not treated, the CDC said.
The virus is transmitted to humans through contact with urine or droppings of infected rodents. The virus is not transmitted through casual contact, and patients are not believed to be infectious before the onset of symptoms, the CDC said.
There has never been person-to-person transmission of Lassa fever documented in the United States, but in rare cases it can be transmitted from person to person through direct contact with a sick person's blood or bodily fluids, through mucous membrane, or through sexual contact, according to the CDC.
About 100,000 to 300,000 cases of Lassa fever, and 5,000 deaths related to Lassa fever, occur in West Africa each year. The New Jersey case is the sixth known occurrence of Lassa fever in travelers returning to the United States since 1969. The last case was reported in Minnesota in 2014. The Minnesota patient was sick with fever and confusion when he arrived in Minneapolis-St. Paul on March 31, 2014, the Minnesota Department of Health said, according to a statement from the Center for Infectious Disease Research and Policy. Samples of the patient's blood were taken and submitted to CDC for testing. The result was Lassa fever.
