Further reports (no. 4) on flies as carriers of infection.

Date:
1911
Catalogue details

Licence: In copyright

Credit: Further reports (no. 4) on flies as carriers of infection. Source: Wellcome Collection.

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    Table IV.—Showing the results of cultures from samples of milk on which flies, infected with B. prodigiosus, B. pyocyaneus and B. anthracis, had been allowed to feed. Time after flies were infected. B. prodigiosus. B pyocyaneus. B. anthracis. 2i hiurs + + + + + + + + + 1 day ... ... ... + + + + + + + + + O n o i7Q J I dry milk ... + + + + + + + + + S Udjb i [ fluid „ ... + + + + + + + + + 9 J 1 dry milk ... + + + + (3 colonies) + + + 1 fluid „ ... + + + + (3 „ ) + + + 4 „ + + 0 + + + 5 „ — + (1 colony) + + 6 » + 0 + (1 colony) 7 „ + 0 + (3 colonies) 8 „ + 0 + 9 „ + 0 0 10 „ + 0 0 11 „ + (3 colonies) 0 + (1 colony) All these experiments show that artificially infected flies, kept in captivity, may contaminate milk on which they feed for several days. As in the last series of experiments (3) many more flies were employed for the experiment with B. prodigiosus than were used in the experiments with other organisms, the relative infecting capacity of the organisms cannot be inferred from the results obtained. The results of the observations recorded in the following table (V) show that though the limbs of the flies infected with B. prodigiosus and B. pyocyaneus were heavily contaminated on the second day, neither of the organisms could be cultivated from them on the eleventh day. B. anthracis was, however, cultivated from the legs and wings even on the eleventh day, a result which is in accordance with previously published experiments (3rd report, p. 32, Table 19). Table V.—Showing the results of cultures made from the limbs and intestinal contents of the flies which had infected the milk samples recorded in Table IV, Time after flies were infected. No. of fly. 5 Cultures from Legs. Wings. Head. Intes- tines. 1. 2. 3. 4. 5. 6. 1. 2. 1 1 day ... | 1 + + 1 + + + + + + + + + + 1 1 2 + + 0 0 0 0 + 0 — + + + ( 1 + + + 0 0 0 + 0 — + + + 1 2 days ... < 2 + + 0 0 0 0 + 0 — + + + 1 B. prodigiosus. i 3 + + + 0 0 0 0 0 + + + + 11 1 1 0 0 0 0 0 0 0 0 + + + + 1 \ ii „ ... -j 2 0 0 0 0 0 0 0 0 + + + + J