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Q Fever

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1295603.  Mon Sep 17, 2018 7:53 am Reply with quote

-The "Q" stands for “query”.
Because researchers didn't know the cause.

-It seems to be everywhere except New Zealand.

Research Story:
-A key point in discovering that Q fever (in Brisbane, Australia) was same as the Nine Mile Agent (in Montana, US) came about from a scientist becoming infected with it from the lab, and then confirming the cause by using his blood in animal experiments.

-Q fever was described in abattoir workers in Brisbane in 1933 and was investigated there by Edward Derrick from 1935. By 1939, he and a collaborator, Frank Macfarlane Burnet in Melbourne, still hadn’t identified the cause, but concluded it was a type of rickettsiae bacteria, so might be transmitted through ticks.

-From 1936 in Montana, Cox and Davis investigated the Nine Mile Agent, and in 1937 concluded that it was transmitted through ticks.

-In 1938 Burnet had sent some Q fever samples to Rolla Eugene Dyer in Washington DC, and Dyer conducted experiments with it.

-Six weeks after these experiments, Rolla Eugene Dyer saw that Cox and Davis had reported rickettsial cultivation in embryonated eggs. Dyer was skeptical, since he was unable to achieve that himself. He visited Cox’s laboratory, was convinced of the results, but also assisted in the lab for a few days, and then when he returned home, he found himself ill.

-To investigate the hypothesis that Dyer was infected with the Nine Mile Agent from Cox’s lab, he performed cross-immunity experiments on guinea pigs with an isolate from his blood. Confirmed.

-Then, to exclude the possibility that he was infected with the Q fever samples in his own lab, he performed more cross-immunity experiments. Also confirmed, but he could only check them one-way. He concluded that the Nine Mile Agent and Q fever were closely related. Yay.

Marrie, T. (1990). Q Fever, Volume 1: The Disease. Boca Raton: CRC Press. [online] Available at:

Maurin, M & Raoult, D. (1999.) ‘Q Fever’, Clin Microbiol Rev, vol. 12, no. 4, pp. 518-544. [online] Available at:

Ministry of Health. (2012.) Rickettsial disease and Q fever. [online] Available at:


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