Annual report of the Medical Department / Nyasaland Protectorate.

  • Nyasaland. Medical Department.
Date:
[1952]
Catalogue details

Licence: Public Domain Mark

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

    29/46 (page 27)
    Dark ground examinations for T. 'pallidum, have been performed with increasing frequency during the year. Since the organization of a venereal disease clinic in the African hospital, Zomba, a laboratory assistant has been in attendance to perform these and to examine urethral smears. The Kahn test continues to be the standard serological test for syphilis used in this country. Parasitology Malaria. 10,523 slides, excluding those from the Chikwawa surveys, were examined, and in 27 per cent, of these malaria parasites were found. The great majority of these were from patients attending the African hospital, Zomba. There was some seasonal variation in incidence as shown bv the following table:— Month January February March April May June July August September October November December Total Slides Malarial Parasites Percentage 729 .. 274 37 1,160 .. 268 23 1,274 .. 335 25 957 .. 297 30 878 .. 184 22 656 .. 189 28 675 .. 182 27 665 213 32 821 .. 183 22 930 .. 183 20 670 .. 203 30 1,108 .. 360 32 The ages of the patients were not recorded, nor was species identification of the parasites practiced consistently throughout the year. It will be noted that the second highest parasite rate occurred in August—-a dry month and that at no time did the rate fall below 20 per cent. It is not suggested that these patients represent a random sample of the population or that these parasite rates can be taken as applying to that population as a whole, for such cases are of necessity selected. They are given in the hope that they may provide an instructive comparison with the results of parasite surveys where random sampling is practised. In fact, the results of two such surveys are known, viz., the Domasi survey made in the early months of 1951 when 18 per cent, of all slides examined were positive and the results of examination of admissions to the Central Prison, Zomba, who were afebrile; when 10 per cent, positives were found in 1952, as is reported separately by the Medical Officer in charge. While not strictly comparable one conclusion seems inescapable; in the adult African there is considerable doubt with regard to the value of the blood slide as sole evidence of the diagnosis of a fever as malaria. Further work on this is required. Amoebiasis. There was a considerable increase in the number of cases where E. histolytica tropho¬ zoites and cysts were found as compared with 1951. These are not, however, a fraction of the numbers reported in earlier years, and amoebiasis cannot be said to constitute a major problem at the present time. Intestinal Worms. The hookworm is the only helminth of major importance in the Zomba area, no other being found with greater frequency than 1.4 per cent, of stools examined. Urinary Bilharzia. 21 per cent, of all urines examined microscopically and 24 per cent, of urines from African patients were found to contain ova of S. haematobium. As in malaria there is a distinct seasonal incidence in this disease. Month January Total African Urines 490 S. Haematobium 96 Per cent. Positive 19.6 February 493 100 20.3 March .. 476 80 16.8 April 476 69 14.5 May 541 129 23.9 June 390 88 22.6 July 416 125 30.0 August .. 425 114 26.8 September 562 149 26.5 October 688 198 28.8 November 594 160 27.0 December 571 137 24.0 It will be noticed that in this disease the maximum number of cases harbouring the parasite were found in the dry months, July to November, and the minimum in March and April, at the end of the rains. Allowing for the usually accepted period of six weeks from cercarial invasion of the body to the appearance of eggs in the urine, the latter may be due to the flushing out of streams during the rainy season. The variation in incidence also suggests that freshly infected cases are more prone to attend hospital than those of longer standing. These figures serve to show the value ol parasite surveys before attempting any conti ol measures in order to assess the optimum time to conduct these.