Lassa Fever, not seen in US for 15 years re-emerges

The New Jersey Department of Health and Senior Services reported today that a 38-year-old Mercer County man died on August 28 from an acute viral disease called Lassa fever, a condition that is rare in the U.S., but endemic to West Africa.

The federal Centers for Disease Control and Prevention (CDC) confirmed the diagnosis of Lassa fever through laboratory tests today.

The man had traveled to Liberia, where he stayed for several months, before returning to the United States and New Jersey on August 24. After arriving in New Jersey and spending several hours at his home, the man presented at the emergency department of Capital Health System at Mercer with symptoms of nausea, vomiting, headache, fever and myalgia. He was admitted and died four days later.

“There is no reason to believe this disease is terrorism-related,” said DHSS Commissioner Clifton R. Lacy, M.D. “A man traveled from a part of the world where this disease is well-known to occur. He brought the illness to New Jersey and unfortunately succumbed to it.

“The disease is not transmitted through casual contact. Our department is working closely with the CDC, Capital Health System, and local health officials to identify any individuals who may be at increased risk due to close contact with the patient,” said Dr. Lacy.

Lassa fever is an acute viral disease that is endemic in portions of West Africa. The disease is animal borne and is transmitted to humans through contact with urine or droppings of infected rodents. It can also be transmitted from person-to-person through blood or bodily fluid that penetrates the skin, through mucous membrane or through sexual contact.

The incubation period for Lassa fever is one to three weeks.

Ribavirin, an antiviral drug, has been shown to be an effective treatment along with supportive care.

In West Africa, there are about 100, 000 to 300,000 cases of Lassa fever and with about 5,000 deaths annually. Overall, death is rare in patients who contract Lassa fever, with only 1 percent of all cases resulting in death. However, between 15 to 20 percent of patients hospitalized with Lassa fever die.

The last case of Lassa fever in New Jersey was approximately 20 years ago. The last case in the United States was in 1989. Both cases were travel-related.

No fever or other evidence of infection has been reported to date among individuals who may have had contact with the 38-year-old Trenton man who died on August 28 of Lassa fever, a virus that is rare in the U.S. but endemic to West Africa. The man returned from a five-month stay in Liberia on August 24, 2004. He flew on Continental Airlines into Newark Liberty International Airport and took a NJ Transit train to Trenton.

Officials from the Trenton Health Department and the state Department of Health and Senior Services (DHSS) have been monitoring family members and Capital Health System-Mercer Medical Center has been monitoring the more than 130 health care workers who may have come in contact with the patient while hospitalized from August 24-28, 2004.

Lassa fever is not easily spread through person-to-person contact. The health care workers who were exposed to the patient are considered at low risk.

The Trenton Health Department has also been in contact with the nursing director of the school system attended by children of the patient. As a precaution, the children will not attend school until after September 18, when the incubation period (the period between acquisition of infection and onset of illness) and the risk of disease will have passed.