Thursday, November 27, 2014

Bubonic Plague Is Back (but It Never Really Left)

A plague outbreak in Madagascar has killed 40 people so far, and due to antibiotic resistance, it could kill many more.

The plague is back. No, not Ebola, but rather infection with the dreaded bacterium, Yersinia pestis. An outbreak in Madagascar, where the disease is endemic, already has involved more than 100 people and killed almost half. The plague made a brief appearance in China earlier this year and continues in the U.S. with a few cases annually.

The current Madagascar outbreak is of particular concern for two reasons. First, cases have arrived in the capital, Antananarivo, a city of more than 2 million located in the center of the island. As was demonstrated with Ebola, once any infection enters a city, the opportunity for spread is greatly heightened, owing to the dense concentration of people, the paucity of clean air and water, and likelihood that vermin are nearby.

The second concern about the current Madagascar outbreak is that cases of pneumonic plague, a highly contagious and lethal form, have been seen. As I described in an article over the summer when the fatal case in China was diagnosed, plague has three distinct clinical forms. First, bubonic (rhymes with pneumonic but is altogether different) is a local infection sequestered in a lymph node. After an infectious flea bites a person and transmits the infection, the bacteria are carried to the closest upstream lymph node where (hopefully) the infection is contained, even without antibiotics. A patient with bubonic is ill with fever and headache, as well as the large lymph node (or bubo) in the appropriate spot, but not contagious.


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