Papers by margaret pinder
Seric high density lipoprotein levels in trypanosensitive and trypanoresistant cattle. Changes during Trypanosoma congolense infection
Acta Tropica, 1987
Seric high density lipoprotein levels in trypanosensitive and trypanoresistant cattle. Changes during Trypanosoma congolense infection
Acta Tropica, 1987
Research Square (Research Square), Feb 22, 2022
The housing stock of rural sub-Saharan Africa is changing rapidly. With millions of new homes req... more The housing stock of rural sub-Saharan Africa is changing rapidly. With millions of new homes required over the coming decades, there is an opportunity to protect residents by screening homes from malaria mosquitoes. This study, undertaken in the Upper River Region of The Gambia, explores local perceptions of what a good house should provide for its inhabitants and responses to living in a house that has been modified as part of a randomized control trial designed to assess whether improved housing provided additional protection against clinical malaria in children (the RooPfs trial). Methods: This descriptive, exploratory study was undertaken over 22 months using mixed-methods (informal conversations, observations, focus group discussions, photovoice, and a questionnaire survey) in a parallel convergent design. Analysis was conducted across the data sets using a framework approach. Following coding, the textual data were charted by a priori and emerging themes. These themes were compared with the quantitative survey results. The nature and range of views about housing and the RooPfs study modifications and the relationships among them were identified and described. The data were derived from a total of 35 sets of observations and informal conversations in 10 villages, 12 discussions with the photovoice photographers, 26 focus group discussions (across 13 villages) and 391 completed questionnaires. The study participants described a 'good house' as one with a corrugate-metal roof, cement walls (preferably cement block, but mud block covered with cement plaster was also an acceptable and cheaper substitute) and well-fitting doors. These features align with local perceptions of a modern house that provides social status and protection from physical harms. The RooPfs modifications were largely appreciated, although poor workmanship caused concerns that houses had become insecure. However, the long-term trusting relationship with the implementing institution and the actions taken to rectify problems provided reassurance and enhanced acceptability. In developing housing to address population needs in Africa, attention should be paid to local perceptions of what is required to make a house secure for its inhabitants, as well as providing a healthy environment.
PubMed, Sep 1, 1987
Nonpermissiveness to trypanosome infection has been correlated in some instances with the presenc... more Nonpermissiveness to trypanosome infection has been correlated in some instances with the presence of toxic serum factors, e.g. high density lipoproteins (HDL) of human serum can lyse T.b. brucei. The present study examines the possibility of a role for such factors in West African cattle that are resistant to trypanosomiasis. Cattle used in this study were previously selected as resistant or sensitive to trypanosomiasis under heavy natural Glossina challenge. - A comparison of the direct effect of serum from trypanoresistant and trypanosensitive Baoulé cattle on the development of pathogenic bloodstream or metacyclic forms of T. congolense, using modifications of the blood infectivity incubation test, failed to demonstrate a difference between these cattle. High density lipoproteins and cholesterol levels were compared in 115 cattle of known sensibility to trypanosomiasis. HDL-cholesterol formed 91% of the total plasma cholesterol. HDL-cholesterol levels in Zebu (mean of 111.8 mg/100 ml) were significantly higher than those in Baoulé cattle (86.2 mg/100 ml). There was no significant difference, however, in these levels between trypanoresistant (73.4 mg/100 ml) and trypanosensitive (84.5 mg/100 ml) Baoulé. Alterations in HDL-cholesterol levels were monitored during an experimental cyclic infection with T. congolense in 5 Zebu and 9 Baoulé. HDL-cholesterol levels decreased in all animals concomitantly with the appearance of trypanosomes in the blood and returned rapidly to their starting values after parasite elimination following drug treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
PubMed, Jun 1, 1983
Ten animals from a reputedly trypanosensitive bovine breed, the Zebu, and ten from a reputedly tr... more Ten animals from a reputedly trypanosensitive bovine breed, the Zebu, and ten from a reputedly trypanotolerant breed, the Baoulé, were exposed to natural trypanosome challenge in an area of high Glossina density. The ten Zebus and five of the Baoulés died within 6 to 11 weeks with heavy parasitaemia and severe anaemia. The five other Baoulés showed little or no parasitaemia, no anaemia and were all in good condition after weeks of exposure: Seven animals of a herd of Baoulé/Ndama crosses indigenous to the same area were followed concurrently and showed very rare or no patent parasitaemia. Clearly, only some individuals within a "trypanotolerant breed" are able to withstand natural fly challenge. Selection of trypanotolerant animals has to be done on an individual basis and not on the biometrical characteristics of the breed.
Loa loa: Immunological Responses During Experimental Infections in Mandrills (Mandrillus sphinx)
Experimental Parasitology, Sep 1, 1994
Six intact, adult mandrills (Mandrillus sphinx) were infected with human-derived, diurnal Loa loa... more Six intact, adult mandrills (Mandrillus sphinx) were infected with human-derived, diurnal Loa loa infective larvae. Microfilaremia, hematological, and immunological parameters were followed for 2-4 years. A major aim was to investigate the relationship between specific humoral immunity to microfilariae and microfilaremia and also to assess whether infection led to generalized immune dysfunction. Microfilaremia was similar to previous studies for 4 mandrills, with a prepatent period of 153.5 +/- 10.1 days, a peak of 34-1,798 mf/ml around Day 200, followed by a decline to low, persistent microfilaremia. One mandrill (No. 20) had a longer prepatent period and very low, but persistent, levels of microfilaremia, and one (No. 19) had gradually increasing levels which remained > 10,000 mf/ml for 3 years. To assess generalized immune perturbations several parameters were studied. There was neither generalized leukocytosis nor relative or absolute eosinophila. Serum Ig concentrations were measured from 0-600 days postinfection by radial immunodiffusion using a rabbit anti-mandrill Ig serum, and these were remarkably stable. Proliferative responses of peripheral blood mononuclear cells from these infected mandrills and noninfected controls showed no significant differences in the magnitude of proliferation after stimulation with a range of doses of PHA, PWM, or Concanavalin A. Thus, no evidence of generalized immune dysfunction was found in the peripheral blood. Serum IgG levels to soluble mf antigens were estimated by an indirect ELISA and all animals had maximal levels around Week 22 postinfection, at the time of maximum microfilaremia, and these decreased over the next 2-3 years in all mandrills except No. 19, in which levels remained fairly constant. Serum IgG levels to adult worm antigens showed a similar pattern but were not, or were only slightly, diminished late in infection. Antibody to mf sheath antigens were detected by indirect immunofluorescence and agglutination of live mf. Antibody to sheath antigens were never detected in mandrill 19 but were present from Week 8 postinfection to 2-4 weeks before patency in all the others. Anti-sheath antibodies were not detected in serum at later time points, i.e., postpatency, in any mandrill, even at time points when microfilaremia was < 1 mf/ml. The anti-sheath antibody was IgM and no anti-sheath IgG was detected. Ig was detected on the surface of circulating mf in 1 mandrill (No. 20). The appearance of these antibodies prior to maturation of the adults indicates that certain L4 or immature adult antigens cross-react with the surface of mf.(ABSTRACT TRUNCATED AT 400 WORDS)
The bovine lymphoid system. III. A monoclonal antibody specific for bovine cell surface and serum IgM
PubMed, Jul 1, 1980
Mouse spleen cells from animals immunized with bovine peripheral blood lymphocytes were fused to ... more Mouse spleen cells from animals immunized with bovine peripheral blood lymphocytes were fused to X63 . Ag8 myeloma cells and the activity of one of the resulting myeloma hybrids was characterized. The product of this clone (B5/4.1.4) binds to pentameric bovine IgM isolated from serum but not to serum IgG1 or IgG2. This reagent also binds to cell surface (monomeric) IgM and can be used in immunofluorescence assays to enumerate IgM-bearing cells in lymphoid cell suspensions and to examine B lymphocytes or B lymphocyte derived cells in tissue sections.
Proceedings of the Royal Society of Medicine, Dec 1, 1974
Proliferation and lymphocyte stimulatory capacity of Theileria-infected lymphoblastoid cells before and after the elimination of intracellular parasites
PubMed, Sep 1, 1981
A prominent pathogenic facet of Theileria infections is that the parasite infects lymphocytes and... more A prominent pathogenic facet of Theileria infections is that the parasite infects lymphocytes and 'transforms' them into parasitized lymphoblastoid cells which are highly proliferative and can be cultured indefinitely in vitro. To analyse the relationship between the intracellular parasite and lymphocyte transformation we have studied the effects of eliminating parasites from these lymphoblastoid cells using the naphthoquinone derivative 993.C. Treatment of Theileria-infected lymphoblastoid cells with 993.C gradually eliminates intracellular parasites but cell proliferation is not inhibited until several days after parasite elimination. The proliferating cells no longer contain schizont particles and are medium-sized lymphocytes and small blast cells. The surface phenotype of these cells, as defined by lectins and monoclonal antibodies, remains unchanged after parasite elimination. The division of non-parasitized cells, under the culture conditions examined, was not indefinite. The compound 993.C itself does not appear to be mitogenic and possible mechanisms for this continued division are discussed. It has been previously reported that co-cultivation of irradiated Theileria-infected lymphoblastoid cells with autologous lymphocytes induces marked DNA synthesis in the latter. We examined further the relevance of this observation for immunity to Theileria by using lymphoblastoid cells treated with 993.C. Elimination of intracellular parasites by this compound does not impair the ability of these cells to stimulate DNA synthesis in autologous lymphocytes. Furthermore, lymphocytes from Theileria-immune or non-immune cattle react similarly. The reaction differs from a classical mixed lymphocyte reaction induced by antigens encoded in the main histocompatibility complex since the stimulator cells are exclusively T lymphocyte-derived cells, the magnitude of response is greater and stimulated lymphocytes are able to act as 'stimulator cells' to fresh autologous lymphocytes. Thus we question the immunological relevance of the observed lymphocyte division. The possibility that Theileria-infected lymphoblastoid cells carry viral genomes or infectious virus particles is discussed. Preliminary electron microscopic studies have not revealed any virus particles.
Observations following the cyclical infection of previously uninfected Baoule and zebu cattle with Trypanosoma congolense
L'infection cyclique de cinq zebus et 12 taurins Baoule a ete realisee a l'aide d'une... more L'infection cyclique de cinq zebus et 12 taurins Baoule a ete realisee a l'aide d'une seule piqure de glossine infectee par Trypanosoma congolense . Cinq taurins, eleves a l'etable sous moustiquaire, a l'abri de toute piqure de vecteur depuis leur naissance ont ete suivis comme temoins, le but etant de comparer la reponse immune de ces animaux contre leur premier pic de parasitemie . Les indications preliminaires se resument ainsi : une seule piqure de glossine infectee, et meme une tentative de piqure sans absorption de sang, suffit a infecter un bovin; pas de difference statistique significative pour les reactions cutanees (chancres), les periodes prepatentes, l'evolution des poids et des temperatures rectales pendant la periode d'infection; chute d'hematocrite des zebus tres significativement superieure a celle des taurins Baoule, les taurins et les zebus ont commence a controler leur hematocrite des le 55eme jour post-infection. Les reponses immunes des zebus sont plus elevees en titre mais plus tardives que les taurins. Les animaux ont ete places ensuite dans la nature, dans des conditions de forte infestation glossinaire, afin de comparer leur reaction
Observations following the cyclical infection with Trypanosoma congolense of previously uninfected Baoulé and Zebu cattle
A specific immune mechanism for the resistance of C5781/6 mice to african trypanosomes
Genetic control of host resistance to infection and malignancies
Journal of Helminthology, Dec 1, 1995
The structure of the female reproductive tract, and the patterns of oogenesis, fertilization and ... more The structure of the female reproductive tract, and the patterns of oogenesis, fertilization and embryogenesis were examined from two adult female Loa loa (Nematoda: Filarioidea) from Gabon. They were found to be indistinguishable in the two specimens, and almost indistinguishable from the pattern previously described from Dirofilaria immitis, except in chromosome number. Loa loa has 2n=10+X0.
Effect of passive and active ventilation on malaria mosquito house entry and human comfort: an experimental study in rural Gambia
Journal of The Royal Society Interface
Rural houses in sub-Saharan Africa are typically hot and allow malaria mosquitoes inside. We asse... more Rural houses in sub-Saharan Africa are typically hot and allow malaria mosquitoes inside. We assessed whether passive or active ventilation can reduce house entry of malaria mosquitoes and cool a bedroom at night in rural Gambia. Two identical experimental houses were used: one ventilated and one unventilated (control). We evaluated the impact of (i) passive ventilation (solar chimney) and (ii) active ventilation (ceiling fan) on the number of mosquitoes collected indoors and environmental parameters (temperature, humidity, CO 2 , evaporation). Although the solar chimney did not reduce entry of Anopheles gambiae sensu lato , the ceiling fan reduced house entry by 91% compared with the control house. There were no differences in indoor nightly temperature, humidity or CO 2 between intervention and control houses in either experiment. The solar chimney did not improve human comfort assessed using psychrometric analysis. While the ceiling fan improved human comfort pre-midnight, in the...
Mechanisms of self-cure from Trypanosoma congolense infection in mice
The Journal of Immunology
The mechanism(s) of resistance to African trypanosomiasis caused by Trypanosoma congolense was in... more The mechanism(s) of resistance to African trypanosomiasis caused by Trypanosoma congolense was investigated by using the Dinderesso/80/CRTA/3 isolate to which C57B1/6 are resistant (low parasitemia and self-cure) and BALB/c sensitive (high parasitemia and death). The resistance of C57B1/6 is similar to that found in some natural hosts of African trypanosomes such as certain indigenous West African cattle and wild Bovidae. The antibody response to epitopes exposed on the variant surface glycoprotein of a clone obtained from the Dinderesso/80/CRTA/3 isolate was measured by a complement-mediated lysis assay in C57B1/6 and BALB/c. After infections with 10(4), 10(5), or 10(7) motile organisms, antibody appeared in C57B1/6 4 to 8 days earlier than in BALB/c. Peak antibody titers were similar in both strains but were reached about 4 days earlier in C57B1/6. In this strain, antibody appeared during and controlled the first wave of parasitemia, whereas in BALB/c, parasitemia reached a platea...
Theileria parva parasites transform a subpopulation of T lymphocytes
The Journal of Immunology
... 389 Page 2. 390 MARGARET PINDER, KATHLEEN S. WITHEY, ANDGEORGES E. ROELANTS [VOL. 127 ... 6. ... more ... 389 Page 2. 390 MARGARET PINDER, KATHLEEN S. WITHEY, ANDGEORGES E. ROELANTS [VOL. 127 ... 6. 7. 8. 9. 10. 11. 12. 13. 14. Brown, C. D. G.. DA Stagg. R. E. Purnell, GK Kanhai. and R. C. Payne. infective particles of Theileria parva. Nature 254:lOl. 1973. ...
The Lancet Planetary Health
Background In malaria-endemic areas, residents of modern houses have less malaria than those livi... more Background In malaria-endemic areas, residents of modern houses have less malaria than those living in traditional houses. We aimed to assess whether children in The Gambia received an incremental benefit from improved housing, where current best practice of insecticide-treated nets, indoor residual spraying, seasonal malaria chemoprevention in children younger than 5 years, and prompt treatment against clinical malaria was in place. In this randomised controlled study, 800 households with traditional thatched-roofed houses were randomly selected from 91 villages in the Upper River Region of The Gambia. Within each village, equal numbers of houses were randomly allocated to the control and intervention groups using a sampling frame. Houses in the intervention group were modified with metal roofs and screened doors and windows, whereas houses in the control group received no modifications. In each group, clinical malaria in children aged 6 months to 13 years was monitored by active case detection over 2 years (2016-17). We did monthly collections from indoor light traps to estimate vector densities. Primary endpoints were the incidence of clinical malaria in study children with more than 50% of observations each year and household vector density. The trial is registered at ISRCTN02622179. In June, 2016, 785 houses had one child each recruited into the study (398 in unmodified houses and 402 in modified houses). 26 children in unmodified houses and 28 children in modified houses did not have at least 50% of visits in a year and so were excluded from analysis. 38 children in unmodified houses were recruited after study commencement, as were 21 children in modified houses, meaning 410 children in unmodified houses and 395 in modified houses were included in the parasitological analyses. At the end of the study, 659 (94%) of 702 children were reported to have slept under an insecticide-treated net; 662 (88%) of 755 children lived in houses that received indoor residual spraying; and 151 (90%) of 168 children younger than 5 years had seasonal malaria chemoprevention. Incidence of clinical malaria was 0•12 episodes per child-year in children in the unmodified houses and 0•20 episodes per child-year in the modified houses (unadjusted incidence rate ratio [RR] 1•68 [95% CI 1•11-2•55], p=0•014). Household vector density was 3•30 Anopheles gambiae per house per night in the unmodified houses compared with 3•60 in modified houses (unadjusted RR 1•28 [0•87-1•89], p=0•21). Interpretation Improved housing did not provide protection against clinical malaria in this area of low seasonal transmission with high coverage of insecticide-treated nets, indoor residual spraying, and seasonal malaria chemoprevention.
Background: The housing stock of rural sub-Saharan Africa is changing rapidly. With millions of n... more Background: The housing stock of rural sub-Saharan Africa is changing rapidly. With millions of new homes required over the coming decades, there is an opportunity to protect residents by screening homes from malaria mosquitoes. This study, undertaken in the Upper River Region of The Gambia, explores local perceptions of what a good house should provide for its inhabitants and responses to living in a house that has been modified as part of a randomised control trial designed to assess whether improved housing provided additional protection against clinical malaria in children (the RooPfs trial).Methods: This descriptive, exploratory study was undertaken over 22 months using mixed-methods (informal conversations, observations, focus group discussions, photovoice, and a questionnaire survey) in a parallel convergent design. Analysis was conducted across the data sets using a framework approach. Following coding, the textual data were charted by a priori and emerging themes. These the...
Those carrying gametocytes at day 0 were excluded from the denominator at subsequent follow-up days (see data table)
Copyright information: Taken from "Chloroquine/Sulphadoxine-Pyrimethamine for Gambian Childr... more Copyright information: Taken from "Chloroquine/Sulphadoxine-Pyrimethamine for Gambian Children with Malaria: Transmission to Mosquitoes of Multidrug-Resistant "PLoS Clinical Trials 2006;1(3):-.Published online 21 Jul 2006PMCID:PMC1513405. © 2006 Hallett et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Bars represent prevalence of gametocyte carriage, with error bars showing 95% CIs. Lines represent arithmetic mean gametocyte density in carriers only.
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Papers by margaret pinder