Imported Lassa Fever Case in New Jersey

 

On September 2, 2004, results of laboratory testing performed at the Centers for Disease Control and Prevention (CDC) support a diagnosis of Lassa fever in a 38-year-old man who died in a New Jersey hospital on August 28. The patient had returned to the United States on August 24 after reportedly spending 5 months in Liberia, where Lassa fever is endemic. This is the first report of a travel-related case of Lassa fever in the United States since 1989. 

 

Lassa fever is an acute viral disease caused by Lassa virus, an arenavirus that is found throughout much of western Africa.  The incubation period is usually about 10 days (range 6 to 21 days).  The illness is characterized by fever, muscle aches, sore throat, nausea, vomiting, and chest and abdominal pain.  Most (about 80%) human infections are mild or asymptomatic; in severe cases, hypotension or shock, hemorrhage, seizures, and death may occur.  In disease-endemic areas, Lassa fever causes 100,000 to 300,000 human infections and approximately 5,000 deaths each year. 

 

Lassa virus is spread to humans primarily through contact with the excreta of infected rodents.  Person-to-person transmission is uncommon and occurs through direct unprotected contact with blood and other body fluids of an infected person. The virus is not spread by casual contact.  Although several cases of imported Lassa fever have been reported previously, secondary transmission to other persons has been extremely rare among both travelers and healthcare workers in non-endemic areas.

 

Interim Guidance for Risk Assessment and Management

 

As part of the current investigation, CDC is working with the New Jersey Department of Health and Senior Services and other public health authorities to identify persons who might be at increased risk as a result of close contact with the patient or his body fluids. Public health authorities have established the following criteria for persons who might be at risk.  As a precaution, a low-risk category for contact tracing and follow-up is defined below.

 

            High risk

·      Exposure from a percutaneous injury (e.g., a needlestick or cut with a sharp object) to blood, tissue or other body fluids that are potentially infectious (e.g., urine, vomitus, stool)

·      Exposure from direct, unprotected contact with potentially infectious material (e.g., touching vomitus with an ungloved hand)

·      Exposure via mucosal exposure (e.g., to eyes, nose, mouth) to splashes or droplets of potentially infectious blood and body fluids or sexual contact with a symptomatic patient.

 

Low risk

·      Sharing a room or seated in a vehicle within 6 feet (i.e., coughing distance) of a potentially infectious patient, without direct contact with potentially infectious material

·      Providing routine medical care while using personal protective equipment appropriately

·      Routine cleaning and laundry of contaminated linens and surfaces while using personal protective equipment appropriately

·      Transport of a potentially infectious patient or specimen without direct contact with potentially infectious material

·      Handling of clinical specimens while using personal protective equipment appropriately

 

Available information regarding the patient’s travel itinerary from West Africa is as follows.  The patient left Freetown, Sierra Leone, on Astraeus Flight 72, which departed 11:15 pm on August 23, 2004 and arrived at Gatwick Airport in London, England.  He then traveled on Continental Flight 29, which departed London Gatwick Airport on August 24 and arrived in Newark, N.J., at 3:20 pm on August 24.  CDC is working to obtain the passenger manifests for these flights and will provide passenger seating and contact information for those at risk to state health departments as soon as it is available.  CDC also has contacted health officials in the United Kingdom and the World Health Organization about this case. 

 

People who traveled on these flights and who think they may be at risk are advised to monitor their health for 21 days after their travel (i.e., through September 18, 2004).  Other people, including health-care workers, who think they might be at risk should monitor their health for 21 days after the last potential exposure. If fever of 101ºF or greater develops, these persons should contact their state or local health departments for further instructions. 

 

This investigation is ongoing.  At this time public health authorities are attempting to identify persons at risk for exposure.  Persons in New Jersey who believe they may be at risk should contact the New Jersey health department hotline at 1-866-234-0964.  Persons residing in other states should contact their state or local health departments. Additional information about Lassa fever and patient management is provided in the flow charts at the end of this document.

 

Laboratory Diagnostics and Additional Information

 

Common causes of fever should be included in the differential diagnosis in addition to consideration of Lassa fever as an etiology. Specific diagnostic testing for Lassa fever is available at CDC (phone: 404-639-1115).  Additional information about Lassa fever testing is available on the CDC website at http://www.cdc.gov/ncidod/dvrd/spb/mnpages/dispages/lassaf.htm.  CDC information about infection control is available at  http://www.cdc.gov/ncidod/hip/.

 

For additional information about the case in New Jersey, please see the website of the New Jersey Department of Health and Senior Services http://www.state.nj.us/health/ or contact the health department’s hotline at 1-866-234-0964.  For more information about Lassa fever, please see the CDC website at http://www.cdc.gov.