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Film, presented by Dr. K. C. Willett. Life history of the tsetse fly
LABORATORY MEETING
291
Dr. A. M. Jordan and Dr. W. B. Petana (W.A.I.T.R., Kaduna): Film, presented by Dr. K. C. Willett. Life history of the tsetse fly. The film, made in the Entomology Section of the West African Institute for Trypanosomiasis Research, showed the full life history of Glossina palpalis, as illustrating, except in its habitat, all species of Glossina. Beginning with the newly emerged fly, the processes of mating, larviposition, burrowing, pupation, eclosion and expansion of the wings were all shown and the film ended with sequences of the typical feeding behaviour of the tsetse-fly. Criticisms and suggestions for improvement of the film were invited as it is hoped to make copies of it, if required, available for teaching.
THE ROSS INSTITUTE
Dr. D . J. Bradley: A simple and rapid method for counting schistosome eggs in urine. In studies of the epidemiology of urinary schistosomiasis the need for quantitative measures of the urinary egg load has become increasingly recognized. The eggs have usually been counted by centrifugation of the urine sample, subsampling of the deposit, and counting the eggs on slides. This involves several accurate measurements and gives only a temporary preparation. The present technique avoids these disadvantages. It was developed at Mwanza, Tanganyika at the same time as that of Bell (1963, Bull World Hlth. Org., 29, 525) which is used for stool samples, and the following brief description concentrates on the differences between the two techniques. The urine sample is agitated and a known volume is drawn up into a mounted graduated pipette by suction from a syringe. This sample is then ejected into a small glass cylinder (15 m m diameter) on a strip of Whatman No. 1 filter paper. Beneath the cylinder, in the centre of a large fiat perspex stand, is a small sintered glass disc to which suction is applied by a filter pump. The urine is sucked through the paper whilst the eggs are left behind. The pipette and cylinder are washed through by saline from a reservoir, to which teepol has been added to lyse any red cells. When a series of samples have been filtered onto the strip it is removed. The eggs are stained using a saturated solution of ninhydrin in saline followed by gentle heating. The eggs then appear purple. The papers may be varnished and the eggs are mounted in a perspe~: grid, damped, and counted at a magnification of x25 under a binoc~alar microscope.
Dr. D. M. Forsyth and Dr. D. J. Bradley (Bilharzia R e s e a r c h Unit~ Ross Institute) Radiological manifestations of urinary schistosomiasis in apparently normal, healthy, primary schoolchildren. The incidence of infection with Schistosoma haematobium amongst the children attending the primary school at Usagara, near Mwanza, Tanganyika, is 95 per cent. The 100 boys and girls of standards IV and V (age range 10-16, mean 13) were submitted to radiological examination of the urinary tract and significant pathology change was found in 20. X-rays from 18 of these were demonstrated. The radiographs showed (a) bladder calcification alone (8 children); (b) persistent unilateral ureteral deformity (5); (e) bladder calcification combined with unilateral hydronephrosis (2); and one child each with (d) calcification of the bladder and unilateral hydronephrosis; (e) calcification of the bladder and persistent ureteral deformity; and (f) bilateral hydronephrosis. NATIONAL
INSTITUTE
FOR MEDICAL
RESEARCH
Dr. J. A. Armstrong, Dr. K. N. Brown and Dr. R. C. Valentine The ingestion of protein molecules by blood forms of Trypanosoma rhodesiense. From what is known of the fine structure of trypanosomes it might be supposed that the organized layer of tubular elements ("pellicular fibrils") beneath the cell membrane would tend to obstruct the occurrence of active phagocytosis over much of the cell surface. However, in 1960 Steinert and Novikoff were able to demonstrate protein ingestion in crithidial forms of the frog trypanosome, T. mega, by incubating the parasites in a ferritin-containing medium. Electron microscopy of the treated cells revealed ferritin molecules inside cytoplasmic vesicles, presumably as a consequence of phagocytosis. T o test the hypothesis further, we have carried out a similar experiment using blood forms of T. rhodesiense, with the aim of identifying points of entry at the cell surface.
291
Dr. A. M. Jordan and Dr. W. B. Petana (W.A.I.T.R., Kaduna): Film, presented by Dr. K. C. Willett. Life history of the tsetse fly. The film, made in the Entomology Section of the West African Institute for Trypanosomiasis Research, showed the full life history of Glossina palpalis, as illustrating, except in its habitat, all species of Glossina. Beginning with the newly emerged fly, the processes of mating, larviposition, burrowing, pupation, eclosion and expansion of the wings were all shown and the film ended with sequences of the typical feeding behaviour of the tsetse-fly. Criticisms and suggestions for improvement of the film were invited as it is hoped to make copies of it, if required, available for teaching.
THE ROSS INSTITUTE
Dr. D . J. Bradley: A simple and rapid method for counting schistosome eggs in urine. In studies of the epidemiology of urinary schistosomiasis the need for quantitative measures of the urinary egg load has become increasingly recognized. The eggs have usually been counted by centrifugation of the urine sample, subsampling of the deposit, and counting the eggs on slides. This involves several accurate measurements and gives only a temporary preparation. The present technique avoids these disadvantages. It was developed at Mwanza, Tanganyika at the same time as that of Bell (1963, Bull World Hlth. Org., 29, 525) which is used for stool samples, and the following brief description concentrates on the differences between the two techniques. The urine sample is agitated and a known volume is drawn up into a mounted graduated pipette by suction from a syringe. This sample is then ejected into a small glass cylinder (15 m m diameter) on a strip of Whatman No. 1 filter paper. Beneath the cylinder, in the centre of a large fiat perspex stand, is a small sintered glass disc to which suction is applied by a filter pump. The urine is sucked through the paper whilst the eggs are left behind. The pipette and cylinder are washed through by saline from a reservoir, to which teepol has been added to lyse any red cells. When a series of samples have been filtered onto the strip it is removed. The eggs are stained using a saturated solution of ninhydrin in saline followed by gentle heating. The eggs then appear purple. The papers may be varnished and the eggs are mounted in a perspe~: grid, damped, and counted at a magnification of x25 under a binoc~alar microscope.
Dr. D. M. Forsyth and Dr. D. J. Bradley (Bilharzia R e s e a r c h Unit~ Ross Institute) Radiological manifestations of urinary schistosomiasis in apparently normal, healthy, primary schoolchildren. The incidence of infection with Schistosoma haematobium amongst the children attending the primary school at Usagara, near Mwanza, Tanganyika, is 95 per cent. The 100 boys and girls of standards IV and V (age range 10-16, mean 13) were submitted to radiological examination of the urinary tract and significant pathology change was found in 20. X-rays from 18 of these were demonstrated. The radiographs showed (a) bladder calcification alone (8 children); (b) persistent unilateral ureteral deformity (5); (e) bladder calcification combined with unilateral hydronephrosis (2); and one child each with (d) calcification of the bladder and unilateral hydronephrosis; (e) calcification of the bladder and persistent ureteral deformity; and (f) bilateral hydronephrosis. NATIONAL
INSTITUTE
FOR MEDICAL
RESEARCH
Dr. J. A. Armstrong, Dr. K. N. Brown and Dr. R. C. Valentine The ingestion of protein molecules by blood forms of Trypanosoma rhodesiense. From what is known of the fine structure of trypanosomes it might be supposed that the organized layer of tubular elements ("pellicular fibrils") beneath the cell membrane would tend to obstruct the occurrence of active phagocytosis over much of the cell surface. However, in 1960 Steinert and Novikoff were able to demonstrate protein ingestion in crithidial forms of the frog trypanosome, T. mega, by incubating the parasites in a ferritin-containing medium. Electron microscopy of the treated cells revealed ferritin molecules inside cytoplasmic vesicles, presumably as a consequence of phagocytosis. T o test the hypothesis further, we have carried out a similar experiment using blood forms of T. rhodesiense, with the aim of identifying points of entry at the cell surface.