Q Fever in the United States

The preceding articles in this series cover the clinical and epidemiologic aspects of the outbreak of Q fever at Amarillo, Texas, in March 1946. The present report describes the results of complement fixation tests for Q fever obtained with serums from patients infected in this outbreak. The first significant indication that the Amarillo outbreak of illnesses was caused by the strain of rickettsia responsible for Q fever came from complement fixation tests done on convalescent serums. Burnet and Freeman, 1 Cox 2 and Dyer, Topping and Bengtson 3 utilized direct rickettsial agglutination, while Bengtson 4 first applied the complement fixation technic using yolk sac antigen in serologic tests for Q fever. With serums obtained from patients infected in the Amarillo outbreak, a modified Kolmer, quantitative complement fixation procedure with overnight ice box fixation was employed. The Q fever antigen 5 was prepared from a strain isolated in 1935 from Dermacentor