U.S. man returning from Liberia dies of Ebola-like Lassa fever

A man returning to the United States from Liberia has died of Lassa fever, a viral disease common in West Africa but rarely seen in the United States.

The patient, who has not been named, traveled from Liberia to JFK International Airport in New York with a stop in Morocco on May 17. He reported no symptoms such as fever when he arrived in the United States, the U.S. Centers for Disease Control and Prevention (CDC) said in a late Monday night statement.

The next day, the patient went to a hospital in New Jersey with symptoms of a sore throat, fever and tiredness, but when asked about his travel history he did not report his travel to West Africa, the CDC said.

The patient was sent home the same day and returned to the hospital three days later when symptoms worsened. He was then transferred to a treatment center prepared to treat viral hemorrhagic fevers. Samples submitted to the CDC tested positive for Lassa fever early Monday and the patient died Monday evening in isolation, the CDC said.

The New Jersey case is the sixth known occurrence of Lassa fever in travelers returning to the United States since 1969, not including convalescent patients.

Although Lassa fever can produce hemorrhagic symptoms in infected people, the U.S. health agency noted that the disease is different from Ebola, which is responsible for the current outbreak in West Africa.

According to the CDC, Lassa fever has similar symptoms to Ebola but is less infectious and less likely to be fatal.

"In general, Lassa fever is less likely to be fatal than Ebola (approximately 1 percent case fatality rate for Lassa vs. approximately 70 percent case fatality rate for Ebola without treatment) and less likely to be spread from person to person," the CDC statement said.

Casual contact is not risky and patients are not believed to be infectious before the onset of symptoms.

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, said the CDC said.

Currently, the U.S. CDC is working with public health officials to generate a list of people who had contact with the patient. Those identified as close contacts of the patient will be monitored for 21 days to see if symptoms occur.

Lassa fever kills about 5,000 people each year in West Africa where it is carried by rodents and transmitted to humans through contact with urine or droppings of infected rodents. Endite