Biological Warfare in the 1940s and 1950s

To the Editor: The review¹ of our book by Drs Wilde and Johnson misrepresents the science and history of biological warfare (BW) during the Korean War era. They fail to cite studies and original sources that might have changed their conclusions about "experiments that do not seem logical, based on the level of knowledge that existed in 1950 as well as today."

Wilde and Johnson dismiss as "anecdotal" our evidence from Chinese and North Korean medical sources by claiming that (1) Chinese medical science was backward, and no one with appropriate training evaluated the evidence; (2) the scientific information was vague or incorrect; (3) BW using insects as vectors is fanciful, as insects cannot survive air drops; (4) the outbreaks were of endemic diseases that probably occurred naturally.

The first claim is simply wrong. The Chinese medical scientists involved had affiliations with at least 30 major European and US educational institutions. Others graduated from Peking Union Medical College, affiliated with the Rockefeller Institute and praised by the most famous US epidemiologist of the day, Hans Zinsser.

Second, Wilde and Johnson say the medical reports are unconvincing. However, close reading reveals scientific rigor and restraint. For instance, from suspect air drops they identified the reservoir of scrub typhus, the vole Microtus, and its trombiculoid mite vector. Unable to culture its agent, Rickettsia tsutsugamuchi, nor identify cases of scrub typhus, they refrained from claiming a scrub typhus BW attack. They also reported suspect air drops containing Collembola (springtails) although these were not known disease vectors. A 1957 US Army report described unusually widespread R tsutsugamuchi infection in multiple mite and rodent species during the war in the battlefield area. This paper revealed that Collembola was used in Army laboratories for the mass culture of trombiculoid mites.

Third, Wilde and Johnson discount air-dropped munitions, citing their unpublished experiments with an automobile and a butterfly net. It is documented that Japanese BW scientists successfully experimented with air-dropped insects. We described a document in which G. B. Reed, head of the Canadian biological weapons research laboratory and an expert on insect vectors, informed his government that, "The dropping of insects from the air is entirely feasible," and the Chinese and North Korean evidence credible. It is on the record that the closely coordinated Canadian and US programs developed insect vectors and air-drop munitions during WWII, through the Korean War era and after. By the early 1950s the US Civil Defense Agency was producing training films warning of insect-vector BW.

Finally, every infectious-disease outbreak must be considered in terms of its specific epidemiology. Wilde and Johnson dispute our claims by citing a heterogeneous group of diseases that naturally occur in "Asia" over "decades." Contemporary records detail anomalous outbreaks of disease and specific circumstances.

Wilde and Johnson ignore a wealth of valid medical evidence, supporting nonmedical data, and other corroborating documentation indicating that there were ample means, motive, and opportunity for the United States to explore biological warfare in China and Korea.