Laboratory Infection with Psittacosis Virus Treated with Penicillin and Sulfadiazine and Experimental Data Bearing on the Mode of Infection

In a case of acute pneumonitis in a laboratory worker, a tentative diagnosis of psittacosis was made on the basis of symptomatology and a history of exposure to the virus. Intensive penicillin therapy was begun on the fourth day of illness, and, because of a possibility of exposure to Whitmore's bacillus, sulfadiazine therapy was begun in addition on the following day. Remission of fever and symptoms occurred within 36 hours after initiation of penicillin therapy. Psittacosis virus, similar in properties to the strain implicated in the history of exposure, was subsequently isolated from sputum taken on the third day of illness; and a complement-fixing titer of 1:160 against the psittacosis group of viruses was obtained in a serum specimen taken on the 12th day, specimens taken earlier having had markedly lower titers. Tests for infection by other agents were negative. The diagnosis of psittacosis was thus amply confirmed. The dramatic recovery that followed institution of chemotherapy is in line with animal experiments which show that this strain of psittacosis virus is sensitive to both penicillin and sulfadiazine. The history of exposure involved an ampule of frozen concentrated virus which was found to have a minute perforation at its base. Twelve days before onset of symptoms the patient, having handled the ampule as its contents were beginning to thaw, noted a fine jet issuing from its base and impinging against the palm of his hand. Subsequent simulation of this incident, using the same ampule containing a suspension of Serratia marcescens, indicated the production of a viable aerosol with a concentration at the level of the patient's upper respiratory passages which seemed sufficient to account for the infection. The concentration of the aerosol thus experimentally produced was found to be considerably greater in still than in circulating air. The findings are believed to throw light on the general problem of airborne laboratory infections due to highly infectioe agents, and to suggest means for their prevention.