Annual report of the Department of Public Health / Union of South Africa.

  • South Africa. Department of Health
Date:
[1924]
Catalogue details

Licence: Public Domain Mark

Credit: Annual report of the Department of Public Health / Union of South Africa. Source: Wellcome Collection.

    55/60 (page 53)
    Fresh introduction of infection to Durban (1902)—probably by infected rats from the f orage ship “ Kassala ” from Argentine ports. Extension to Johannesburg (1904)—probably by introduction of plague-infected rodents from one or other of the infected coastal towns. Epizootics amongst “ domestic ” rodents in infected towns, with concurrent epidemics in man. Spread from rodent to rodent and from rodent to man mainly by agency of fleas. Infected wild rodents found on outskirts of Knysna, Port Elizabeth, East London, etc., mainly striped mice (Arvicanthus). 1912.—Fresh outbreak in Durban, following plague epizootic amongst rodents at the docks—probably a fresh importation of infection. 1914.—Epidemic in Midland districts, Cape Province, commencing on remote farm in Tarka district; continued into 1915 ; source of infection not discovered at the time. 1916. —Prevalence in north-western Orange Free State; also outbreak in Uitenhage District, Cape Province. 1917. —Outbreak at Welverdiend, Potchefstroom District, Transvaal. Continued prevalence in north-western Orange Free State and Cape Midlands. 1918-1920.—Continued slight prevalence in north-western Orange Free State. Strong suspicion that infection being perpetuated and spread by wild rodents ; special investigations and digging experiments instituted. (See Annual Health Report for 1920, pages 13-15.) February, 1921.—After lengthy investigation, existence of plague infection amongst wild rodents established on farm near Bothaville, where human cases had recently occurred. Further proof of similar nature found in other localities. (See Annual Health Report for eighteen months ended 30th June, 1922, pp. 15 and 16 ; also Paper by Mitchell, S.A. Medical Congress, Cape Town, 9th October, 1921, published in Journal of Hygiene of 17th January, 1922, Vol. XX, No. 4 ; and another Paper by Haydon, published in Tran¬ sactions of Royal Society of Medicine, 28th October, 1921, and reprinted in Lancet, 26th November, 1921.) 1923.—Wild rodent survey of the Orange Free State and Cape Midlands made ; evidence of present or recent plague infection found over wide area. (See Health Report for yea ended 30th June, 1923, pp. 18-20.) Foregoing and subsequent investigations have established the broad facts regarding the perpetuation and spread of plague by wild rgdents. The various wild rodents involved and the role played by each has been in large measures ascertained. Their fleas and other ectoparasites have been examined and many of them identified ; several new varieties of flea found. Information regarding these matters still incomplete. B.—Matters for Further Investigation and Research. 1. Zoological. Careful survey of veld rodents and associated animals, and their habits as regards burrowing, nesting, migration, etc. Variation of habits owing to droughts, etc ; effects of grain-growing, relationship with domestic rodents. Part played by different species in (a) perpetuating, (b) spreading, plague infection. Habits of different species of rodents in regard to travelling by rail or in crates, etc. 2. Entomological. Fleas and other ectoparasites of rodents, both domestic and veld, and associated animals. Identification of different species. The life-history and bionomics of different species under natural conditions. Conditions favouring flea multiplication and prevalence ; effects of climate, rainfall, and season ; time of year of maximum prevalence, and whether this varies in different localities. Breeding and feeding habits of fleas. Migration or transferability of fleas from one species to another and their biting habits on different animals and on man. Migratory habits in connection with dead carcasses, deserted rodent-burrows, etc. Distances to which fleas may migrate without hosts. Capacity of fleas for survival without hosts under different conditions. Conditions favouring survival of flea larvae. Hibernation of fleas and flea larvae—under what conditions and in what relation to their natural hosts ? Other ectoparasites of rodents and their life-history and bionomics.