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.

    22/46 (page 20)
    he obtained a positive result. There is no evidence that under natural conditions flies have anything to do with the spread of diphtheria, but it is, of course, conceivable that they may convey the infection under suitable conditions. DYSENTEEY. We have no direct evidence bearing upon flies in relation to dysentery. Smith (1903) writes: “An old idea of some Anglo- Indian surgeons was that dysentery could be caught by using the same latrine as a dysentery patient. There may be something in this the ubiquitous fly may, therefore, be a dysentery inoculator in open camp latrines.” Bbrgey (1907) also considers that flies may disseminate dysentery as they do cholei'a and typhoid. FRAMBCESIA TEOPICA (YAWS). Wilson (1868, p. 466) says the belief prevails in the West Indies that the disease is conveyed from one individual to another by flies. Hirsch (1896) reports two cases in which he thinks the disease was conveyed by flies. Both patients were living among Fijian children who had the disease. One patient had an uncovered ulcer, the other sores on his feet ; “ thus each had raw surfaces which could be inoculated by the poison,” and would naturally be sought by flies. Cadet (1897) says that lesions of the skin (ulcers, insect or leech-bites, scratches, &c.) are necessary for infection to take place. This may occur through direct contact, through infected clothes or flies, the latter transporting the virus on their feet which are soiled with diseased secretions. Experiments. Castellani (1907, pp. 567-568) tested the matter of the fly- transmission of Yaws by experimental methods. He allowed M. domesticu to feed (1) upon yaws material (scraping from slightly ulcerated papules), and (2) upon semi-ulcerated papules on the skin of three yaws patients. In both cases he was able to discover the Spiro- chceta pertenuis in microscopic preparations made from the flies’ mouth-parts and legs. Furthermore, he allowed M. domestica to feed on yaws material (1 and 2 as above) and afterwards transferred them to scarified areas upon the eye-brows of monkeys. Of 15 monkeys thus experimented upon three developed yaws papules at the places which had been contaminated by the flies. Castellani concludes that “ Yaws is generally conveyed by actual contact, but under certain circumstances it may be conveyed by flies and possibly by other insects.” OPHTHALMIA. The part played by non-biting flies in the spread of Ophthalmia is well recognised to-day. Budd, as early as 1862, considered it was fully proven that flies serve as carriers of Egyptian ophthalmia ; Laveran (1880), writing of Biskra, says the same. Howe (1888, p. 323 ; cited by Abel, 1899), stated that (1) the number of cases increases rapidly from the moment when flies are present in large