Explore the recorded discovery and history of Coxiella burnetii, with source links and stated limits.
PHAC describes C. burnetii as a pleomorphic, Gram-negative, spore-forming coccobacillus existing in two forms: a small-cell variant with condensed nucleoid filaments and a metabolically active large-cell variant. It is an obligate intracellular pathogen that completes its development cycle in the phagolysosome — the acidic compartment most bacteria avoid. CDC states that these bacteria naturally infect some animals such as goats, sheep and cows, and that people become infected by breathing in dust contaminated by infected animal feces, urine, milk and birth products. PHAC reports that approximately 1 to 10 organisms are required to cause infection, one of the lowest infectious doses recorded for any bacterium, and that Q fever is endemic worldwide except New Zealand.
LPSN records the basonym “Rickettsia burneti” Derrick 1939. The epithet honours Frank Macfarlane Burnet, who first studied the properties of this organism. The disease name “Q fever” came from query fever, reflecting that its cause was unknown when the outbreaks were first investigated.
LPSN records Coxiella burnetii corrig. (Derrick 1939) Philip 1948, effectively published in Public Health Reports in a note commenting on the name of the Q-fever organism, and retained on the 1980 Approved Lists of Bacterial Names. Type strain ATCC VR-615.
PHAC records 3,523 cases in the Netherlands between 2007 and 2009, the largest outbreak in its account. It is included because it shows the scale an airborne, low-dose organism can reach in a community near intensive livestock farming; it is not the origin of the species.
These references do not identify a first person ever infected. Q fever was investigated as an unexplained febrile illness before its cause was described, so the 1939 and 1948 records date scientific description and naming rather than a first human case or a geographic origin.
Source check: 2026-09-20. Educational content; independent scientific review remains pending.