Out of Africa to a New Jersey hospital

No secondary infections reported in 188 contacts

The first case of imported Lassa fever diagnosed in the United States since 1989 set off a flurry of public health and clinical investigations, but thus far no secondary transmission has been reported, according to the Centers for Disease Control and Prevention (CDC).

Lassa fever, a viral disease with a rodent host, is rarely imported to countries outside of those areas in Africa where the disease is endemic. Many cases may be asymptomatic, but approximately 15% to 20% of patients hospitalized for Lassa fever die from the illness.

On Aug. 28, 2004, a 38-year-old man living in New Jersey died from Lassa fever after returning from travel to West Africa. Within hours of his arrival in the United States, the patient sought treatment and was hospitalized in Trenton, NJ, for persistent fever, chills, sore throat, diarrhea, and back pain. The patient died on the fourth day of hospitalization, and diagnosis of Lassa fever was confirmed postmortem.

A total of 188 people had contact with that patient during the period when he likely was infectious. Five family members were classified as high risk. The remaining 183 low-risk contacts included 139 health care workers. Another 19 low-risk contacts were fellow passengers on the patient’s airline flight from London to Newark. Investigators have not been able to find three of the passengers, but all other contacts were not infected.