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Human malaria parasites
186
LABORATORY DEMONSTRATIONS
1,500 m, Bulinus africanus being the species of the group found at the highest altitude. Recent extensive snail collections in Kitui district in the semi-arid part of Kenya have demonstrated: (i) Lymnaea columella as a species new to Kenya; (ii) the occurrence of B. truncatus, as identified by cytological and biochemical means in Kitui district; (iii) B. nasutus as a widespread species in these semi-arid parts. In the semi-arid parts of Kenya the potential of both B. nasutus and B. truncatus as intermediate hosts of S. haematobium and S. bovis is discussed and it is suggested that further studies in the area might clarify the situation regarding these two snail species.
in-vitro lymphosuppressed observed in heavily infected patients P.KERN, H. @ELDMEIER,G.NIEL* fiir Schi’su. TropenBernhard-Nocht-Institut
Schistosomiasis: cyte reactivity
krankheiten,
Bernhard-Nocht-Strasse 74, D-2000 Federal Republic de Parasitologic et de Medicine tropicale, Ho’strital Piti&Salaetridre, Paris
Hamburg 4, German *Service
Two
groups
with- schistosomiasis and S. mansoni) were examined: 10 male adults with a long history of schistosomiasis, and 13 male schoolboys with a presumed history of > two years. The egg concentration in the urine was assessed by a filtrationtechnique (FELDMEIER et al., 1979; Tropenmed. 30, 417), and in stool by the Kato techParasit., nique. High egg concentrations in urine and stool were observed in nearly all of the Sudanese schoolboys. Mononuclear cells (MNC) were obtained after density gradient centrifugation of peripheral blood. Lymphocyte transformation was achieved in cultures supplemented with foetal calf serum (FCS) or autologous serum (AS) using S. mansoni adult worm antigen or mitogens as source of stimulation. After five days the incorporation of 3H-TdR was measured. MNC of patients with low urinary egg output, or none, could reliably be stimulated by S. mansoni antigen (20 pglculture). The incorporated 3H-TdR reached a value equivalent to those of cultures stimulated by mitogens. However, lymphocyte reactivity of 10 patients with heavy infection (2 100 eggs/100 ml urine) was considerably suppressed in cultures stimulated by S. mansoni antigen as compared to the reactivity of 13 patients with egg counts of 0 to lOO/lOO ml urine (mean 1724 cpm and 22,428 cpm, respectively, mean of unstimulated controls 250 cpm). Cultures supplemented with the patient’s own sera revealed similar results. Mitogen stimulation was pronounced in all cultures, as expected. Despite the longevity of the presumed infection in both patient groups, the in vitro lymphocyte activation induced by parasite antigens was clearly related to worm infestation. A suppression of (Schistosoma
of patients
haematobium
AND POSTERS
cellular immunity generated by specific antigen was assumed in those patients with a massive egg excretion indicating a heavy worm load.
Human Federal
Malaria
malaria
parasites
A. 0. LAMBO & Vector Control Lagos, Nigeria
This exhibit comprised tions of three species
Unit,
Yaba,
microscopic of human
demonstraplasmodia, Plasmodium faiciparum. P. malariae and P. ovale. from Nigeria; the infections showed high parasitl aemia in all the cases. The most significant observation was an unusual case of an extraordinarily high gametocytaemia in a schoolchild aged seven years, in whom one microscope field revealed more than 120 gametocytes. This case is unique in our 14 years’ experience in malaria field work. Generally only four to six gametocytes can be found in one field. What are the factors responsible for this unusual case of extraordinarily high level of gametocytaemia? Is it a case of loss of immunity or a genetical factor which is gametocyte-induction orientated? In all the four slides demonstrated (three thick and one thin blood films) full dehaemoglobinization of the thick blood films and a deeply stained thin film were obtained; the staining was based on a Giemsa staining technique developed by the author (LAMBO, A. O., 1972; W. Afr. Med. J., 21, 93-96).
Observations on pyrexia induction by human plasmodial infections relative to other pathogens among volunteers A. 0. LAMBO Federal
Malaria
& Vector Control Lagos, Nigeria
Unit,
Yaba,
Local strains of human plasmodia were demonstrated to show the extent to which they contribute to the incidence of high body temperature in an African community and situation. The exhibits, in the form of diagrams and graphs, showed the results of investigations, carried out during the 12 years 1967 to 1978, among 2,787 patients with of incessant fever. Urine, faeces, complaints sputum and blood specimens of the patients, mostly Nigerians with only two Caucasians, were examined for the causative agents of pyrexia with special emphasis on plasmodia. Plasmodial parasite infection rate for the patients studied within the period ranged between 9.42”,, and 38.40”,,, indicating that infections or physiological disorders, in addition to plasmodia were responsible for the symptomatic fevers. Helminthic infections, amoebiasis bacterial infections and viruses were imolicated in some cases. The range of body temperafure for each vear (1967-78) was determined and its relationshcp with malarial parasitaemia was discussed. It was concluded that it is unjustified to regard all pyrexia manifestations as being due to malaria among Nigerians and other populations in malaria endemic areas of the world.
LABORATORY DEMONSTRATIONS
1,500 m, Bulinus africanus being the species of the group found at the highest altitude. Recent extensive snail collections in Kitui district in the semi-arid part of Kenya have demonstrated: (i) Lymnaea columella as a species new to Kenya; (ii) the occurrence of B. truncatus, as identified by cytological and biochemical means in Kitui district; (iii) B. nasutus as a widespread species in these semi-arid parts. In the semi-arid parts of Kenya the potential of both B. nasutus and B. truncatus as intermediate hosts of S. haematobium and S. bovis is discussed and it is suggested that further studies in the area might clarify the situation regarding these two snail species.
in-vitro lymphosuppressed observed in heavily infected patients P.KERN, H. @ELDMEIER,G.NIEL* fiir Schi’su. TropenBernhard-Nocht-Institut
Schistosomiasis: cyte reactivity
krankheiten,
Bernhard-Nocht-Strasse 74, D-2000 Federal Republic de Parasitologic et de Medicine tropicale, Ho’strital Piti&Salaetridre, Paris
Hamburg 4, German *Service
Two
groups
with- schistosomiasis and S. mansoni) were examined: 10 male adults with a long history of schistosomiasis, and 13 male schoolboys with a presumed history of > two years. The egg concentration in the urine was assessed by a filtrationtechnique (FELDMEIER et al., 1979; Tropenmed. 30, 417), and in stool by the Kato techParasit., nique. High egg concentrations in urine and stool were observed in nearly all of the Sudanese schoolboys. Mononuclear cells (MNC) were obtained after density gradient centrifugation of peripheral blood. Lymphocyte transformation was achieved in cultures supplemented with foetal calf serum (FCS) or autologous serum (AS) using S. mansoni adult worm antigen or mitogens as source of stimulation. After five days the incorporation of 3H-TdR was measured. MNC of patients with low urinary egg output, or none, could reliably be stimulated by S. mansoni antigen (20 pglculture). The incorporated 3H-TdR reached a value equivalent to those of cultures stimulated by mitogens. However, lymphocyte reactivity of 10 patients with heavy infection (2 100 eggs/100 ml urine) was considerably suppressed in cultures stimulated by S. mansoni antigen as compared to the reactivity of 13 patients with egg counts of 0 to lOO/lOO ml urine (mean 1724 cpm and 22,428 cpm, respectively, mean of unstimulated controls 250 cpm). Cultures supplemented with the patient’s own sera revealed similar results. Mitogen stimulation was pronounced in all cultures, as expected. Despite the longevity of the presumed infection in both patient groups, the in vitro lymphocyte activation induced by parasite antigens was clearly related to worm infestation. A suppression of (Schistosoma
of patients
haematobium
AND POSTERS
cellular immunity generated by specific antigen was assumed in those patients with a massive egg excretion indicating a heavy worm load.
Human Federal
Malaria
malaria
parasites
A. 0. LAMBO & Vector Control Lagos, Nigeria
This exhibit comprised tions of three species
Unit,
Yaba,
microscopic of human
demonstraplasmodia, Plasmodium faiciparum. P. malariae and P. ovale. from Nigeria; the infections showed high parasitl aemia in all the cases. The most significant observation was an unusual case of an extraordinarily high gametocytaemia in a schoolchild aged seven years, in whom one microscope field revealed more than 120 gametocytes. This case is unique in our 14 years’ experience in malaria field work. Generally only four to six gametocytes can be found in one field. What are the factors responsible for this unusual case of extraordinarily high level of gametocytaemia? Is it a case of loss of immunity or a genetical factor which is gametocyte-induction orientated? In all the four slides demonstrated (three thick and one thin blood films) full dehaemoglobinization of the thick blood films and a deeply stained thin film were obtained; the staining was based on a Giemsa staining technique developed by the author (LAMBO, A. O., 1972; W. Afr. Med. J., 21, 93-96).
Observations on pyrexia induction by human plasmodial infections relative to other pathogens among volunteers A. 0. LAMBO Federal
Malaria
& Vector Control Lagos, Nigeria
Unit,
Yaba,
Local strains of human plasmodia were demonstrated to show the extent to which they contribute to the incidence of high body temperature in an African community and situation. The exhibits, in the form of diagrams and graphs, showed the results of investigations, carried out during the 12 years 1967 to 1978, among 2,787 patients with of incessant fever. Urine, faeces, complaints sputum and blood specimens of the patients, mostly Nigerians with only two Caucasians, were examined for the causative agents of pyrexia with special emphasis on plasmodia. Plasmodial parasite infection rate for the patients studied within the period ranged between 9.42”,, and 38.40”,,, indicating that infections or physiological disorders, in addition to plasmodia were responsible for the symptomatic fevers. Helminthic infections, amoebiasis bacterial infections and viruses were imolicated in some cases. The range of body temperafure for each vear (1967-78) was determined and its relationshcp with malarial parasitaemia was discussed. It was concluded that it is unjustified to regard all pyrexia manifestations as being due to malaria among Nigerians and other populations in malaria endemic areas of the world.