BOX 2-5 Imported Lassa Fever

In early 1989, a man who had visited Nigeria for a funeral became sick after returning to the United States. The patient was a 43-year-old mechanical engineer living in a Chicago suburb. Shortly after his return from Nigeria, he walked into a health clinic complaining of fever and sore throat. The area was in the midst of a winter influenza epidemic, and he was advised to take acetaminophen for the fever but was not otherwise treated. The symptoms worsened, and when he returned three days later, swollen lymph nodes and a phlegm-covered throat were noted, for which he was given penicillin. Five days later, his condition had deteriorated; his symptoms now included bloody diarrhea and facial swelling, and he had elevated liver enzymes.

An attentive specialist who saw the patient at a local hospital suspected a viral hemorrhagic fever after reviewing the patient's history. That history revealed that the patient had been in Nigeria for his parents' funerals until a few days before his illness began. His mother's death, of a febrile illness, had occurred two weeks before the patient's symptoms appeared, and was followed by his father's death from a similar illness 10 days later. The travel and disease history made the clinician suspect Lassa fever, a disease known to be endemic to Nigeria, and he called the CDC in Atlanta. The CDC was later able to confirm the diagnosis of Lassa fever by virologic methods. Ribavirin, the only drug presently available for this infection, was ordered for the patient, but he died of cardiac arrest before the drug arrived.

A total of 102 people had come into contact with the patient when he was likely to have been infectious. High-risk contacts (in this instance, immediate family who had had intimate contact, washed soiled linens, and shared utensils) were also placed on prophylactic ribavirin. Medium-risk contacts included a laboratory technician, the patient's nurse, and a physician who was not wearing gloves when he inserted an intravenous line into the patient.

None of the contacts became infected, a somewhat unusual circumstance in the case of this disease. The patient was undiagnosed for almost two weeks, during which time the virus could have been passed to the patient's care givers, to other patients of these care givers, and to family members. Transmitted primarily through direct contact with the blood or other bodily fluids of an infected person, Lassa has been suspected in some cases to be spread by airborne transmission. Had this been true in the Chicago case, the number of direct and indirect contacts in danger of contracting the disease could have been much greater.

The ease with which people can travel around the world today means that "exotic" diseases can move just as quickly. Physicians must be consistently aware of infectious diseases that originate in other parts of the world, and vigilant about obtaining a travel history for patients with undiagnosed illness, especially if it is accompanied by fever.

SOURCE: Holmes et al., 1990.



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