Annual report of the Medical Department / Uganda Protectorate.

  • Uganda Protectorate. Medical Department.
Date:
[1952]
Catalogue details

Licence: Public Domain Mark

Credit: Annual report of the Medical Department / Uganda Protectorate. Source: Wellcome Collection.

    25/94 (page 19)
    The immediate effects of the dosing were impressive. Within fifty minutes of the first application larvae were noted streaming away from their rock and grass attachments, and within four hours many were dead. The lethal effect was noted at the Owen Falls one hour later and at the distal end of the breeding stretch, 40 miles distant, about thirty-six hours later. The rocks were rapidly covered with algal growth, upon which fish browsed and snails increased. On the tenth day a drop in the number of adult flies caught was recorded, and on the thirteenth day no flies could be found, although previously catches of 100 flies per boy-round were being recorded. A small backwater to which the treated water did not penetrate needed special attention, and after the first month only one fly per week was caught. For two months after the cessation of treatment it seemed that the effect might be durable. A few flies were brought in by Africans, but their origin was not ascertainable. Ten weeks after the cessation of spray¬ ing an adult fly was caught on the routine fly-rounds, and a week later breeding was discovered in the Nile. It is of interest that the balance of nature has been disturbed, for no S. nili or S. hargreavesi have yet been reported, and the larvae now present (S. damnosum, S. griseicolle and S. adersi) include one species which did not breed in the Nile before the treat¬ ment. This is S. adersi, which is found on the islands in the Lake, and is suspected to occur at points along the Busoga coast line; the larvae are attached to rocks covered with the spray of breakers, and can tolerate slower running water than can S. damnosum. Various hypothetical reasons for the failure to secure eradication of S. damnosum are being investigated; among them are the possibilities that females aestivate during dry weather, or that reinfestation may have occurred from unsuspected breeding places on the lake shore where wave action may produce the requisite amount of aeration. Schistosomiasis The survey of vesical schistosomiasis in Lango District has delimited the areas of heavy infection, and work continued on methods to control the disease. The action of Nilodin was found to be disappointing, while previous experience writh tartar emetic had revealed that its effect is often transient. Infection takes place in scattered discrete pools, and the application of copper sulphate appears to be the most effective method of control. The work is being carried out by health staff, the African local authority supplying the material. (3) DIRECT INFECTIONS Anthrax 123 cases with 6 deaths are known to have occurred during 1952, but it is likely that cases of internal anthrax may pass undiagnosed. The largest focus reported is in Bugungu on the north-east shore of Lake Albert, the infection being conveyed by goats and cattle and maintained by failure to bury infected carcasses.