A Nurse Epidemiologist’s Notes on Issues Raised by a Recent Death from Lassa Fever

By Betsy Todd, MPH, RN, CIC, AJN clinical editor

Lassa fever is most often diagnosed by using enzyme-linked immunosorbent serologic assays (ELISA), which detect IgM and IgG antibodies as well as Lassa antigen. Reverse transcription-polymerase chain reaction (RT-PCR) can be used in the early stage of disease. The virus itself may be cultured in 7 to 10 days, but this procedure should only be done in a high containment laboratory with good laboratory practices. Immunohistochemistry, performed on formalin-fixed tissue specimens, can be used to make a post-mortem diagnosis.

Some aspects of last month’s case of Lassa fever in New Jersey seemed to parallel the story of Thomas Duncan, who died last October in Dallas after contracting Ebola virus disease in Liberia.

A man arrived in the U.S. from Western Africa. He was screened for Ebola at the airport and instructed to monitor his temperature for 21 days. The next day, he developed a fever. Instead of calling the county health department, he headed to a hospital. He reportedly didn’t mention his travel history to staff, and was sent home on antibiotics. His condition worsened, and three days later he returned to the ED. When clinicians learned that he had recently arrived from Liberia, he was isolated, admitted, and tested for Ebola and Lassa. Positive for Lassa fever, he died soon afterwards.

Like Ebola, Lassa is a zoonotic hemorrhagic fever endemic to Western Africa. As with Ebola, the early symptoms of Lassa fever are nonspecific: fever, headache, malaise, nausea, vomiting . . .

But here the similarities end. Unlike Ebola, 80% of Lassa fever cases are mild or asymptomatic, and the overall case fatality rate is just 1%. (The risk of dying rises to 15%–20% if the disease progresses and requires hospitalization.) The most common complication of Lassa fever is deafness—one-third of those infected experience some degree of hearing loss—which occurs in both mild as well as severe cases.

Missed opportunities? This recent and upsetting story once again highlights the limitations of communicable disease follow-up based on self-monitoring and accurate individual reporting. Airport temperature screening of passengers arriving from certain geographical areas (which appears to be of questionable value) is supposed to result in the isolation and testing of anyone with a fever. But the vast majority of disembarking passengers are afebrile. They are instructed to monitor their temperature for a prescribed period of time (depending upon the disease of concern), and to call their local health department if they develop symptoms.

There are, of course, many holes in this surveillance “safety net.” Passengers may not reveal their connection to an epidemic area because of fear of reprisal, denial of their own at-risk status, or language-related misunderstandings at the point of screening. They may or may not subsequently monitor their health. When fever develops and becomes undeniable, they may not know how to contact their local health department, or if they do call, may quickly become impatient if met with a busy signal or no answer. Panic about what symptoms might mean will cause some people to run to the nearest ED for medical care; health department notification is not a high priority when you think you’re fighting for your life.

After the Lassa case, some in the media asked why health departments don’t routinely notify area hospitals that a “rule-out” case of serious communicable disease is self-monitoring in their region. This may sound helpful, but the necessary public health resources are simply not available. Can we notify all hospitals near a person’s home, and workplace, and their mother’s house, and that music festival they’re attending next weekend? And if hospitals could be notified of every single rule-out that steps off a plane, would the information quickly reach every staff person who might be the first to encounter the patient?

Consideration of practical issues is unsatisfying to those who just want to “see something done” to stop the spread of frightening diseases. Increased public health funding (which is abysmally low compared with the money poured into acute care) would begin to address surveillance holes, as would global financial support for countries whose poor health infrastructures prevent them from containing endemic diseases when cases appear.

Meanwhile, we can best protect ourselves and our patients via continuing but unglamorous efforts to sharpen our infection prevention and control skills. Always do the following:

  • Question patients about travel history, including non-international travel. Movement within one country can transmit measles, avian flu, tickborne diseases, etc., from region to region.
  • For acute respiratory illness, ask about occupational or other intense exposures to birds, bats, or other wildlife.
  • Be quick to isolate when communicable disease is suspected. It’s always wiser to discontinue isolation that turns out to be unnecessary than to isolate after exposing dozens of people to infection.
  • When communicable disease is suspected, wear the recommended personal protective equipment (PPE), and pay attention when donning and doffing your gear.

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About the Author:

Clinical editor, American Journal of Nursing (AJN), and epidemiologist

Comments are moderated before approval, but always welcome.