Public health officials are contacting airline passengers who may have been exposed to a Minnesota man with an unusual viral illness during a flight on Monday.
The man, who was returning to Minnesota from West Africa, was admitted to a hospital after arriving at Minneapolis-St. Paul International Airport with fever and confusion soon after his flight's arrival.
On Thursday, he tested positive for Lassa fever — a sometimes fatal disease that is transmitted to humans through contact with infected rodent urine or droppings. It can sometimes lead to severe bleeding syndrome. The patient did not develop bleeding.
Health officials are not identifying the airline or the hospital to protect the patient's identity. He is currently in stable condition and is recovering.
"Casual contact is not a risk factor for getting Lassa fever," said Barbara Knust, an epidemiologist with the Centers for Disease Control. "People will not get this infection just because they were on the same airplane or in the same airport." The last case of Lassa fever in the United States, reported in 2010, was travel-related.
"This imported case is a reminder that we are all connected by international travel," CDC Director Tom Frieden said. "A disease anywhere can appear anywhere else in the world within hours."
The Minnesota Department of Health is working with the hospital to notify health care providers or other staff members who may have had contact with the patient.
Lassa fever is common in West Africa, where 100,000 to 300,000 cases are reported each year, with about 5,000 deaths. The incubation period for the virus is one to three weeks.
The risk to the general public also is low because the hospital acted quickly, said Dr. Aaron DeVries, medical director of the Infectious Disease Division of the Minnesota Department of Health.
"It was a very astute clinician who was thinking about this kind of possible infection and contacted us and did all of the appropriate measures to minimize the risk that others might be exposed to the blood and body fluids of this patient," he said.