From 2004: “Army Test in 1950 May Have Changed Microbial Ecology”
July 14th, 2014Via: San Francisco Chronicle:
Serratia is a bacterium that some doctors and residents of the Bay Area have been familiar with for many years.
In 1950, government officials believed that serratia did not cause disease. That belief was later used as a justification for a secret post-World War II Army experiment that became a notorious disaster tale about the microbe.
The Army used serratia to test whether enemy agents could launch a biological warfare attack on a port city such as San Francisco from a location miles offshore.
For six days in late September 1950, a small military vessel near San Francisco sprayed a huge cloud of serratia particles into the air while the weather favored dispersal.
Then the Army went looking to find out where it landed. Serratia is known for forming bright red colonies when a soil or water sample is streaked on a culture medium — a property that made it ideal for the bio-warfare experiment.
Army tests showed that the bacterial cloud had exposed hundreds of thousands of people in a broad swath of Bay Area communities including Sausalito, Albany, Berkeley, Oakland, San Leandro, San Francisco, Daly City and Colma, according to reports that later were declassified. Soon after the spraying, 11 people came down with hard-to-treat infections at the old Stanford University Hospital in San Francisco. By November, one man had died. Edward Nevin, 75, a retired Pacific Gas and Electric Co. worker recovering from a prostate operation, had succumbed to an infection with Serratia marcescens that attacked his heart valves.
The outbreak was so unusual that the Stanford doctors wrote it up for a medical journal. But the medics and Nevin’s relatives didn’t find out about the Army experiment for nearly 26 years, when a series of secret military experiments came to light.
The Chronicle’s David Perlman, who reported on the revelations in 1976, found no evidence that the Army had alerted health authorities before it blanketed the region with bacteria. As the news surfaced, doctors started wondering whether the Army experiment that seeded the Bay Area with serratia two decades earlier might be responsible for heart valve infections then cropping up as well as serious infections seen among intravenous drug users in the ’60s and ’70s, said Dr. Lee Riley, a professor of infectious disease at UC Berkeley.
Before the 1950 experiment, serratia was not a common environmental bacteria in the Bay Area nor did it frequently cause hospital infections, Riley said.
