Intestines in the Time of Cholera

The world has experienced 7 cholera pandemics since 1817. The first six were caused by the classic biotype of the O1 serogroup of Vibrio cholerae. The 7th pandemic which began in 1961 and is still ongoing (with spread to Haiti and Mexico) is due to the less virulent El Tor biotype of O1 V.cholerae.  In a project, my colleagues and I estimated global cholera costs as exceeding $3 billion annually. 

It was in 1849 during the 2nd pandemic that Dr. John Snow made his pathbreaking epidemiological discovery regarding the role of water in the spread of the cholera microbe--yet to be identified (see The Ghost Map and The Strange Case of the Broad Street Pump). During that pandemic, Dr. John Neill of Philadelphia preserved an intestine from a patient for further study.

The New England Journal of Medicine just published the results of a successful attempt to extract the cholera microbe from that over-a-century old specimen. 

The bacterium recovered was of the classical biotype (as predicted) and had a striking similarity to the reference strain of the classic biotype suggesting that little evolution has occurred since 1849 because of some selective pressure that is constraining its genome. 

Cholera is a fascinating disease--see its biography--and this study fills in a few chapters in its life with humans.