Human ornithosis is probably more prevalent than is commonly recognized and may be present in a fairly high percentage of the recently increasing number of cases diagnosed as virus pneumonia. The literature on the subject has been recently summarized by Heilman and Herrell.1 The chief difficulty in establishing the diagnosis is the lack of convenient laboratory facilities in America for making complement fixation tests on the patient's blood serum. As far as I could ascertain, the laboratory of Dr. K. F. Meyer at the University of California is the only one on this continent that does this work.
Ornithosis and psittacosis are strikingly similar in their clinical manifestations and probably differ only in the source and causative virus. The onset is rather gradual and in many features resembles the onset of typhoid except that diarrhea is not present and an atypical pneumonia with a dry, irritating, unproductive cough soon
Turgasen FE. HUMAN ORNITHOSIS TREATED WITH PENICILLIN. JAMA. 1944;126(18):1150-1151. doi:10.1001/jama.1944.82850530002007a