The man recently returned from Liberia, arriving at the New York City’s JFK International Airport on May 17.
Dr. Tom Frieden, director of the U.S. Centers for Disease Control and Prevention in Atlanta said, the man grew critically ill after his return, suffering from multiple organ failure.
Health officials said that there are worries regarding the spread of the disease. The Lassa fever does not spread through casual contact.
In the past, half of the dozen cases have been diagnosed in travelers from West Africa and none of them ever spread the illness person to person.
CDC and the New Jersey health officials as a precaution are trying to track down and monitor everyone the man was in contact with during the past week.
The illness is commonly seen in West Africa and some of the countries struck by the recent Ebola epidemic.
The last confirmed case of Lassa fever was seen in a traveler returning to the United Stated was in Minnesota last year.
Lassa fever is far less likely to be fatal than Ebola and less likely to be spread from person to person. About 80 percent of the cases are mild, but in severe cases, patients can suffer vomiting, organ failure, fever, shock and even bleeding from the eyes, nose and gums. It is fatal in about 1 percent of cases. Sometimes survivors are deaf for the rest of their lives.
It can spread through contact of blood, faces or vomit of an infected person.
In West Africa, Lassa virus is carried by rodents and transmitted to humans through contact of urine or droppings of infected rodents.
The man had no symptoms during the flight, but a say later went to a New Jersey hospital suffering from a sore throat and lethargy.
Hospital officials asked the man about his travel history but the man did not say that he had recently been to West Africa.
Three days later he returned to hospital with more severe symptoms, he was transferred to the second Hospital Saturday. On Monday, CDC lab tests of the patient’s blood test confirmed Lassa fever.
Health officials note than exotic illnesses are only plane ride away.
Frieden said, “We expect to see Lassa fever and other infections like this. Because of Ebola, we’re now better prepared to deal with it.”
Lassa fever was named after a Nigerian town where Western trained doctors first noted in 1969.