For the Month of December 1964

During December, 1,719 human isolations of salmonellae were reported. The average number of isolations per week was 344, a decrease of 55 from the figure for November (Figure 1).

For the past four months the percentage of j>. derby recoveries has remained relatively constant at slightly more than 4 per cent. Prior to a large interstate hospital-associated outbreak in 1963 attributed to this serotype, the reported recoveries of S. derby accounted for approximately 2 per cent of all salmonellae reported from human specimens. The course of the epidemic due to JS. derby is roughly portrayed in Table VII by the number and per cent of isolations reported to the Salmonella Surveillance Unit between November 1962 and December 1964.

Stephen B. Thacker CDC Library collection

United States