A person returning to the United States after visiting West Africa has been confirmed as having Lassa fever and is recovering after being treated at a Minnesota hospital, the U.S. Centers for Disease Control and Prevention announced Friday.
The CDC was quick to stress that Lassa fever, a severe viral illness, is not related to Ebola fever, the deadly viral illness that is currently making headlines due to a widespread outbreak in a handful of West African countries.
However, the imported case of Lassa fever "is a reminder that we are all connected by international travel. A disease anywhere can appear anywhere else in the world within hours," CDC Director Dr. Tom Frieden said in an agency news release.
According to the CDC, Lassa fever is relatively common in West Africa, but very rare in the United States, with only seven other cases -- all travel-related -- ever reported in the United States. The last case was reported in Pennsylvania in 2010.
In West Africa, rodents carry the Lassa virus and transmit it to people through contact with rodent urine or droppings. In rare cases, Lassa virus can be transmitted person-to-person through blood, body fluids or sexual contact. Up to 300,000 cases of Lassa fever, and 5,000 deaths, occur in West Africa each year, the CDC said.
"Although Lassa fever can produce hemorrhagic symptoms in infected persons, the disease is not related to Ebola hemorrhagic fever, which is responsible for the current outbreak in West Africa," the CDC stressed in its news release.
The Ebola outbreak, centered in Guinea, has so far killed 92 people and may have spread to the nearby countries of Liberia, Sierra Leone and Mali, the BBC reported Friday.
Regarding the Lassa fever case, "the risk to other travelers and members of the public is extremely low," Dr. Martin Cetron, director of the CDC's Division of Global Migration and Quarantine, said in the agency news release.
As part of its investigation, the CDC is working with airlines to obtain contact information on passengers and crew who were seated near the patient.
However, Barbara Knust, an epidemiologist in the CDC's Division of High-Consequence Pathogens and Pathology, said in the news release that "casual contact is not a risk factor for getting Lassa fever. People will not get this infection just because they were on the same airplane or in the same airport."