DURING the course of investigations on the psittacosis-lympho-granuloma venereum group of diseases, an opportunity was afforded to test the fixation of complement in a number of samples of serum in the presence of psittacosis antigen. These samples were submitted by practicing physicians from patients suspected of having psittacosis. For persons whose serum reacted positively, clinical and epidemiologic data were requested and additional serum specimens tested when possible. The results of the complement fixation studies supplemented by the clinical and epidemiologic data form the basis of this report on 21 cases, the disease in none of which was fatal.
Psittacosis is a severe acute infectious disease manifesting itself principally as pneumonitis and characterized by headache, malaise, dry nonproductive cough, chills and usually physical signs of pneumonia. It is contracted by association with birds of various species, chiefly those of the parrot group and pigeons, which are infected with the specific virus.