A Patient in Minnesota Has Lassa Hemorrhagic Fever. (Don't Panic.)

Daliborlev (CC), FLickr

Daliborlev (CC), FLickr

News from the Minnesota Department of Public Health and the Centers for Disease Control and Prevention: A Minnesota traveler returning from Africa has been hospitalized with what the CDC confirms to be Lassa fever, a viral hemorrhagic fever that is often lumped together with Ebola hemorrhagic fever, though they are caused by different organisms.

Given the news from West Africa of the growing Ebola outbreak there — 127 cases including 83 deaths, according to the World Health Organization’s last posted update — I suspect there’s going to be some attention to this case, possibly even some alarm. So, switching from Scary Disease Girl to Scary Disease Killjoy (which is sort of like Phoenix becoming Dark Phoenix, only without any planets blowing up): The Minnesota department says there’s no sign the disease has spread. The CDC says it’s not even likely to have infected passengers on the same airplane.

And if you’re thinking, well, surely this has never happened before, a viral hemorrhagic fever coming to the US via airline: Actually, it’s happened seven times before. And no one caught Lassa from the infected travelers in any of those times — not from sitting next to them, not from living in the same house with them, not from having sex with them. It is a very bad disease. But it is not the threat we like to imagine.

(Sorry to spoil the fun.)

From the Minnesota department’s statement:

The general public is not at risk from this case. The Minnesota patient is recovering and is in stable condition… The ill man flew to Minneapolis-St. Paul on March 31. Promptly after his arrival, the patient was seen by a physician who, given the patient’s travel history and condition, suspected a possible hemorrhagic fever and immediately reported it to MDH.

Since Lassa virus is not spread by casual contact, CDC believes any risk to other airline passengers and crew is extremely low. However, in the interest of protecting passenger health, CDC is working with the airlines to identify passengers and crew who may have had close contact with the ill man during his travel. State and local health departments will reach out to notify these individuals of their possible exposure.

From the CDC’s statement:

Preliminary information indicates that the patient flew from West Africa to New York City and caught another flight to Minneapolis. “Given what we know about how Lassa virus is spread to people, the risk to other travelers and members of the public is extremely low,” said Martin Cetron, M.D., M.P.H., director of CDC’s Division of Global Migration and Quarantine.

“Casual contact is not a risk factor for getting Lassa fever,” said Barbara Knust, D.V.M., M.P.H., an epidemiologist in CDC’s Division of High-Consequence Pathogens and Pathology, which performed the laboratory testing.  “People will not get this infection just because they were on the same airplane or in the same airport.”

Here’s a quick recap of some other times this has happened:

In Philadelphia in 2010: a 47-year-old US resident, originally from Liberia, went home for a visit that included five days in his home village. On the day he left, he started to have fever and chills, and his joints hurt, and he made the natural assumption he was having a bout of malaria. He took malaria drugs, didn’t get better, went to a hospital once he returned to the US, and was diagnosed with Lassa. Out of 140 possible contacts in two countries, no one else caught the disease: not in the hospital, on the airplane, or in his village. He recovered too.

In New Jersey in 2004: A another man originally from Liberia who had gone to look after family farm properties came back to the US very sick, was hospitalized and died. He had changed planes in London, and health authorities from several countries started an international search. He had crossed paths with at least 188 people; none got sick.

In Chicago in 1989: A man from Nigeria went home for his mother’s funeral, came back to the US ill, went home to his wife and six kids, and then was hospitalized and died. More than 100 people were possibly exposed; none got sick.

Now, Lassa is not Ebola: It has a lower mortality rate (10-20 percent, versus 80-90 percent). But for precisely that reason, Ebola is less likely to travel by airplane than Lassa: People who develop symptoms are so sick so rapidly — and so noticeably — that they are unlikely to be allowed on an airplane, or to be able to board.

If I sound cranky  — it’s OK, you can tell me — it’s because earlier this week I ran a panel at a meeting in which researchers talked about the stunning amount of tuberculosis in the world: 1.3 million deaths per year, with an increasing proportion of it drug-resistant. Yet, no one outside the public-health world obsesses about TB, even though MDR-TB actually has occurred and spread in the US. It makes me impatient — and yeah, I acknowledge my culpability in this — how often we choose to focus on the deliciously scary but conveniently far-away, rather than the diseases we could do something about. So I’d like to head that off, for once, if I can.

(David Ropeik, journalist turned risk-perception expert, has written about this too, prompted by a Twitter convo on Ebola that we were both part of.)


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