Laboratory-associated infections: summary and analysis of 3921 cases.

Instances of overt laboratory-associated infection recorded in published reports and additional cases disclosed by questionnaires and personal communications have been tabulated. Of a total of 3921 cases, 2465 occurred in the United States and 164 were fatal. Only 64% of the cases were reported in the literature. Analysis of the available information revealed that only 18% of the infections were due to known accidents; 42% were caused by bacteria; 27% by viruses; 15% by rickettsiae; 9% by fungi; 3% by chlamydiae; and 3% by parasites. It may be significant that fewer infections have been recorded in the past decade than in any of the four preceding decades. Possible reasons for this apparent decrease are discussed.