Further preliminary reports on flies as carriers of infection.

Date:
1909
Catalogue details

Licence: In copyright

Credit: Further preliminary reports on flies as carriers of infection. Source: Wellcome Collection.

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    intestines of flies. As Joseph (1887) and Nuttall (1899) have sugfrested, it appears probable that non-biting flies may, when infected, spread anthrax by depositing the bacilli upon wounds or food. Actual experiments in this direction appear to be lacking. CHOLERA. Moore (1853) drew attention to the necessity of guarding food against flies, because, he supposed, they might disseminate cholera, adding: “ flies in the East have not far to pass from diseased evacuations or from articles stained with such excreta, to food, cooked and uncooked.” Nicholas (1873) writes that in 1849, when cholera prevailed at Malta : “ My first impression of the possibility of the transfer of the disease by flies was derived from the observation of the manner in which these voracious creatures, present in great numbers, and having equal access to the dejections and food of the patients, gorged themselves indiscriminately and then disgorged themselves on the food and drinking utensils. In 1850 the * Superb,’ in common with the rest of the Mediterranean squadron, was at sea for nearly six months; during the greater part of the time she had cholera on hoard. On putting to sea the flies were in great force ; hut after a time the flies gradually disappeared, and the epidemic slowly subsided. On going into Malta harbour, but without communicating with the shore, the flies returned in greater force, and the cholera also with increased violence. After more cruising at sea, the flies disappeared gradually with the subsidence of the disease.” Flugge (1886, pp. 359, 370) expresses his belief that insects (flies) may infect the food in cholera times. Their numbers vary extraordinarily at times and in certain places. They must play an important part, especially when they are numerous. “ A quantitative determination of this influence is, of course, impossible.” Fliigge also draws attention to the fact that the worst cholera months are those in which insects abound. Tsuzuki (1904, p. 77), of the Japanese Army Medical Service, reporting upon the cholera epidemic in North China in 1902, w 1 ites that flies in C'hina are a terrible infliction to the stranger,” and if flies are capable of carrying about the cholera germ they must play an important part in the spread of the disease {see his experiments on p. 17 ; they gave a positive result). Experiments. The first recorded experiments on flies in relation to cholera are those of Maddox (1885), in which Musca vomitoria and Eristalis tenax, &c,., were fed on impure and pure cultures of the cholera vibrio, which were added to sugar. Maddox was evidently not accustomed to bacteriological methods, for he gives a lengthy but unsatisfactory account of his experiments, which do not seem to have attracted any particular attention. He, however, does seem to have determined microscopically the presence of motile cholera vibrios in the dejections of the insects, and, from his observations, concludes that they serve as agents in the spread of cholera. The first to make accurate experimental observations on the part played by flies in the spread of cholera were Tizzoni and Cattani