Early Treatment of Chest Wounds in Middle East
Authors: R. B. Scott
Journal: BMJ (1944)

to stand on the bench until the whey had separated.Twofold dilutions of whey were prepared with 0.85% sodium chloride solution in a volume of 0.5 ml., the dilutions ranging from I in 2 to 1 in 256.Saline controls and normal milk controls were also set up at the time of the experiment.To all the tubes 0.5 ml. of a suspension of S. dublin was added.The opacity of this suspension was adjusted with normal saline solution until it was approximately the same as that of a standard suspension.The suspension was preserved by the addition of 0.4% of chloroform.All the tubes were incubated at 50°C. for two hours and allowed to stand on the bench overnight.The milk of Cow No. 10 was found to contain agglutinins for S. dublin, the titre being I in 32.The test was repeated with another specimen of milk of Cow No. 10, and a titre of 1 in 64 was obtained.The agglutination was of the flaky H type.The whey obtained from the milk of all the other cows did not agglutinate S. dublin in a dilution of 1 in 4. Subsequent examination of the dung of Cow No. 10 showed the presence of S. dublin.Two samples of dung were examined; in both an almost pure culture of S. dublin was obtained on direct plating on Leifson's medium, and many colonies were also detected on MacConkey medium.The identity of the organism was confirmed by Dr. Joan Taylor. DiscussionThree extensive outbreaks of milk-borne gastro-enteritis due to S. dublin have been reported in this country.In the first two outbreaks, which occurred in Dundee in 1926 and 1927 and were reported by Tulloch (1939), the infection was traced to a cow that was ill.In the Wilton outbreak (Conybeare and Thornton, 1938) and in the present one, however, the absence of evidence of illness among the cows presented the problem of finding the animal carrier.Conybeare and Thornton discovered the carrier by examining the antibody content of blood samples of individual cows.They found that about 50% of sera gave an agglutinin titre of 1 in 25.The sera of three cows gave a titre of 1 in 400 or higher, and the dung obtained from one of these cows yielded S. dublin on cultivation.In the present outbreak the search for the carrier was made by determining the agglutinin content of the milk.It was found that milk from healthy cows did not contain any agglutinins for S. dublin and that even a low titre of agglutinins in milk was indicative of infection.It appears, therefore, that milk is a suitable material for serological tracing of carriers of S. dublin not only because it is more easily obtained than blood but also because non-specific agglutinins for S. dublin are not usually present.How the milk became the vehiSle of infection is a, matter of conjecture.As the dung of the carrier cow contained the organism in large numbers it seems probable that the milk became contaminated as a result of faulty methods of produc- tion at the farm.On the other hand, although the milk of this cow was repeatedly examined with negative results, the possibility of intermittent excretion of S. dublin in the milk cannot be excluded.SummaryAn outbreak of milk-borne gastro-enteritis due to Salmonella dublin is described.At least 162 people were affected.There were no deaths.The source of infection was an apparently healthy cow which was excreting large numbers of the organism in the dung.The carrier cow was identified by the agglutinin content of its milk.The milk of normal cows did not possess any agglutinins for S. dublin.