Ornithosis (Psittacosis) in Pigeons and Its Relation to Human Pneumonitis

Abstract

In a previous paper, 1 it was reported that a psittacosis-like virus had been isolated from the lung of a patient who had been exposed to a flock of racing pigeons (Columba livia). Nineteen, or 63%, of the 30 suspected birds gave specific complement-fixation reactions in dilutions of from 1 :8 to 1 :256 (Table I). A virus, indistinguishable from that of the patient, was isolated from the spleens and livers of 4 pigeons which had given a positive, and from 1 pigeon which had given a negative serum reaction. This observation was the prelude to the recognition of the nation-wide existence of a psittacosis-like infection in pigeons—in the future to be described as “Ornithosis.” At least 10 human atypical pneumonias with 2 deaths [California 4 (2 deaths), New York 4, Minnesota 1 and Boston 1] have been traced to exposure to the different species of pigeons exclusively.

Survey of Pigeon Lofts and Isolation of Virus. In order to secure comparative data relative to the extent of ornithosis in lofts and to have available suitable birds for experimental tests, random samples of pigeons were secured from various places in California and other states of the Union. With the exception of 12 squabs from a loft whose old birds were virus-carriers, a universal existence of the infection was recognized with the aid of complement-fixation tests. The virus responsible for these reactions was isolated from the organs of non-reacting as well as of reacting pigeons. The pertinent data thus far obtained are summarized in Table I.

The extraordinarily high percentage of positive results will doubtless raise questions regarding the specificity of the serum-reactions. There is conclusive evidence that they are the result of a response to a psittacotic antigen.