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2. Rotating-crystal Malaria Diagnosis: Pre-clinical validation

Author

Orban, Agnes, Butykai, Adam, Prohle, Zsofia, Fulop, Gergely, Zelles, Tivadar, Forsyth, Wasan, Hill, Danika, Schofield, Louis, Mueller, Ivo, Karl, Stephan, and Kezsmarki, Istvan

Subjects
Physics - Medical Physics, Physics - Biological Physics
Abstract

Improving the efficiency of malaria diagnosis is one of the main goals of current malaria research. We have recently developed a magneto-optical (MO) method which allows high-sensitivity detection of malaria pigment (hemozoin) crystals via their magnetically induced rotation in blood. Here, we validate this technique on laboratory derived blood samples infected with \textit{Plasmodium falciparum}. Using two parasite cultures, the first containing mostly ring stages and the second corresponding to the end of the parasite life cycle, we demonstrate that our novel method can detect parasite densities as low as $\sim$40 and $\sim$10\,parasites per microliter of blood for ring and schizont stage parasites, respectively. This detection limit exceeds the performance of rapid diagnostic tests and competes with the threshold achievable by light microscopic observation of blood smears. Our method can be performed with as little as 50\,microliter of capillary blood and is sensitive to the presence of hemozoin micro-crystals down to ppm concentrations. The device, designed to a portable format for clinical and in-field tests, requires no special training of the operator or specific reagents, except for an inexpensive lysis solution to release intracellular hemozoin. Beyond diagnostics, this technique may offer an efficient tool to study hemozoin formation, trace hemozoin kinetics in the body and test susceptibility/resistance of parasites to new antimalarial drugs inhibiting hemozoin formation.

Published
2013

4. Safety, infectivity and immunogenicity of a genetically attenuated blood-stage malaria vaccine

Author

Webster, Rebecca, Sekuloski, Silvana, Odedra, Anand, Woolley, Stephen, Jennings, Helen, Amante, Fiona, Trenholme, Katharine R., Healer, Julie, Cowman, Alan F., Eriksson, Emily M., Sathe, Priyanka, Penington, Jocelyn, Blanch, Adam J., Dixon, Matthew W. A., Tilley, Leann, Duffy, Michael F., Craig, Alister, Storm, Janet, Chan, Jo-Anne, Evans, Krystal, Papenfuss, Anthony T., Schofield, Louis, Griffin, Paul, Barber, Bridget E., Andrew, Dean, Boyle, Michelle J., de Labastida Rivera, Fabian, Engwerda, Christian, and McCarthy, James S.

Published
2021
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22. Infectivity of Symptomatic Malaria Patients to Anopheles farauti Colony Mosquitoes in Papua New Guinea

Author

Timinao, Lincoln, primary, Vinit, Rebecca, additional, Katusele, Michelle, additional, Koleala, Tamarah, additional, Nate, Elma, additional, Czeher, Cyrille, additional, Burkot, Thomas R., additional, Schofield, Louis, additional, Felger, Ingrid, additional, Mueller, Ivo, additional, Laman, Moses, additional, Robinson, Leanne J., additional, and Karl, Stephan, additional

Published
2021
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24. Pathophysiology of Anemia in HIV-Infected Children Exposed to Malaria

Author

Moraleda, Cinta, Aguilar, Ruth, Quintó, Llorenç, Nhampossa, Tacilta, Renom, Montserrat, Nhabomba, Augusto, Ruperez, María, Aponte, John J, Achtman, Ariel H, Mañú Pereira, María Del Mar, Schofield, Louis, Alonso, Pedro L, Macete, Eusebio, and Menéndez, Clara

Abstract

Anemia is a common condition in HIV-infected children; however, its pathophysiology and the contribution of frequent causes of anemia such as iron deficiency (ID) and malaria are poorly understood. We carried out an ancillary study on the effect of HIV on anemia as part of a case-control study on risk factors of anemia among Mozambican children aged 1-59 months with documented HIV status. Of them, 390 children were admitted to the hospital with anemia (hemoglobin [Hb] < 11 g/dL), whereas 272 children without anemia (Hb ≥ 11 g/dL) were recruited in the community. We assessed differences by HIV status in the presentation of anemia etiological factors and the effect of HIV infection on the association of each factor with anemia. Among the 99 HIV-infected and 563 uninfected children included, HIV-infected anemic children had an increased risk of undernutrition (P < 0.0001), Epstein-Barr virus infection (P < 0.0001), bacteremia (P = 0.0060), a decreased risk of malaria (P < 0.0001), and a similar risk of ID (P = 0.7371) compared with anemic-uninfected children. HIV-infected children were significantly less likely to have anemia associated with Plasmodium falciparum hyperparasitemia (P = 0.0444) and had a lower prevalence of parasitemia in the bone marrow (BM) (P < 0.0001) than anemic-uninfected children. Levels of BM erythropoiesis and dyserythropoiesis were comparable between groups. These findings suggest that the pathophysiology of anemia among HIV-infected malaria-exposed children is not related to HIV-specific effects. For unclear reasons, HIV-infected children had reduced risk of malaria infection, whereas ID prevalence was comparable in HIV-infected and uninfected children, suggesting that iron supplementation recommendations should not be different in HIV-infected children.

Published
2021

25. Additional file 2 of Safety, infectivity and immunogenicity of a genetically attenuated blood-stage malaria vaccine

Author

Webster, Rebecca, Sekuloski, Silvana, Odedra, Anand, Woolley, Stephen, Jennings, Helen, Amante, Fiona, Trenholme, Katharine R., Healer, Julie, Cowman, Alan F., Eriksson, Emily M., Sathe, Priyanka, Penington, Jocelyn, Blanch, Adam J., Dixon, Matthew W. A., Tilley, Leann, Duffy, Michael F., Craig, Alister, Storm, Janet, Chan, Jo-Anne, Evans, Krystal, Papenfuss, Anthony T., Schofield, Louis, Griffin, Paul, Barber, Bridget E., Andrew, Dean, Boyle, Michelle J., de Labastida Rivera, Fabian, Engwerda, Christian, and McCarthy, James S.

Abstract

Additional File 2. Supplementary methods and results for immunogenicity assessments of GAP vaccine. Text S1. Methodology for determining antibody mediated immune response to GAP vaccine. Text S2. Methodology for determining cell mediated immune response to GAP vaccine. Table S1. Antibodies used for flow cytometry. Figure S1. The gating strategy used to identify CD4+ T cells and subsets, as well as the expression of T cell activation markers. Figure S2. The anti-MSP2 IgM response over the course of the study in each subject. Figure S3. The IgG and IgM response to whole parasite lysate over the course of the study in each subject. Figure S4. The frequency of CD4+ T cells, Treg cells, Th1 cells and Tfh cells in peripheral blood mononuclear cells over the course of the study in each subject.

Published
2021
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27. Additional file 3 of Safety, infectivity and immunogenicity of a genetically attenuated blood-stage malaria vaccine

Author

Webster, Rebecca, Sekuloski, Silvana, Odedra, Anand, Woolley, Stephen, Jennings, Helen, Amante, Fiona, Trenholme, Katharine R., Healer, Julie, Cowman, Alan F., Eriksson, Emily M., Sathe, Priyanka, Penington, Jocelyn, Blanch, Adam J., Dixon, Matthew W. A., Tilley, Leann, Duffy, Michael F., Craig, Alister, Storm, Janet, Chan, Jo-Anne, Evans, Krystal, Papenfuss, Anthony T., Schofield, Louis, Griffin, Paul, Barber, Bridget E., Andrew, Dean, Boyle, Michelle J., de Labastida Rivera, Fabian, Engwerda, Christian, and McCarthy, James S.

Abstract

Additional File 3. Supplementary methods and results for in vitro assessments of GAP vaccine. Text S1. Methodology for parasite genotyping. Text S2. Methodology for cytoadherence assays. Text S3. Methodology for scanning electron microscopy. Text S4. Methodology for var gene expression analysis. Table S1. Duration of in vitro culture of P. falciparum prior to harvest for RNA extraction for var gene transcription analysis. Text S5. Results of parasite genotyping. Text S6. Results of scanning electron microscopy analysis of parasite-infected erythrocytes. Text S7. Results of cytoadherence assays. Text S8. Results of var gene expression analysis. Table S2. Most abundantly expressed var genes.

Published
2021
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28. Additional file 1 of Safety, infectivity and immunogenicity of a genetically attenuated blood-stage malaria vaccine

Author

Webster, Rebecca, Sekuloski, Silvana, Odedra, Anand, Woolley, Stephen, Jennings, Helen, Amante, Fiona, Trenholme, Katharine R., Healer, Julie, Cowman, Alan F., Eriksson, Emily M., Sathe, Priyanka, Penington, Jocelyn, Blanch, Adam J., Dixon, Matthew W. A., Tilley, Leann, Duffy, Michael F., Craig, Alister, Storm, Janet, Chan, Jo-Anne, Evans, Krystal, Papenfuss, Anthony T., Schofield, Louis, Griffin, Paul, Barber, Bridget E., Andrew, Dean, Boyle, Michelle J., de Labastida Rivera, Fabian, Engwerda, Christian, and McCarthy, James S.

Abstract

Additional File 1. Supplementary methods and results for subject eligibility and safety assessments. Text S1: Subject eligibility criteria. Table S1: Incidence of adverse events by subject. Table S2: Red blood cell alloantibody test results for Cohort 4 and phenotype of donor red blood cells used for GAP master cell bank manufacture.

Published
2021
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30. Association of early interferon-[gamma] production with immunity to clinical malaria: a longitudinal study among Papua New Guinean children

Author

D'Ombrain, Marthe C., Robinson, Leanne J., Stanisic, Danielle I., Taraika, Jack, Bernard, Nicholas, Michon, Pascal, Mueller, Ivo, and Schofield, Louis

Subjects
Interferon gamma -- Physiological aspects, Interferon gamma -- Research, Natural immunity -- Research, Malaria -- Development and progression, Malaria -- Demographic aspects, Malaria -- Research, Health, Health care industry
Published
2008

39. Synthetic GPI as a candidate anti-toxic vaccine in a model of malaria

Author

Schofield, Louis, Hewitt, Michael C., Evans, Krystal, Siomos, Mary-Anne, and Seeberger, Peter H.

Subjects
Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Author(s): Louis Schofield (corresponding author) [1]; Michael C. Hewitt [2]; Krystal Evans [1]; Mary-Anne Siomos [1]; Peter H. Seeberger [2] The malaria parasite Plasmodium falciparum infects 5-10% of the world's [...]

Published
2002

40. Transcriptional Memory-Like Imprints and Enhanced Functional Activity in γδ T Cells Following Resolution of Malaria Infection

Author

Kumarasingha, Rasika, primary, Ioannidis, Lisa J., additional, Abeysekera, Waruni, additional, Studniberg, Stephanie, additional, Wijesurendra, Dinidu, additional, Mazhari, Ramin, additional, Poole, Daniel P., additional, Mueller, Ivo, additional, Schofield, Louis, additional, Hansen, Diana S., additional, and Eriksson, Emily M., additional

Published
2020
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41. Infectivity of symptomatic malaria patients to Anopheles farauti colony mosquitoes in Papua New Guinea

Author

Timinao, Lincoln, primary, Vinit, Rebecca, additional, Katusele, Michelle, additional, Koleala, Tamarah, additional, Nate, Elma, additional, Czeher, Cyrille, additional, Schofield, Louis, additional, Felger, Ingrid, additional, Mueller, Ivo, additional, Laman, Moses, additional, Robinson, Leanne J., additional, and Karl, Stephan, additional

Published
2020
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42. Decreased bioefficacy of long-lasting insecticidal nets and the resurgence of malaria in Papua New Guinea

Author

Vinit, Rebecca, primary, Timinao, Lincoln, additional, Bubun, Nakei, additional, Katusele, Michelle, additional, Robinson, Leanne, additional, Kaman, Peter, additional, Sakur, Muker, additional, Makita, Leo, additional, Reimer, Lisa, additional, Schofield, Louis, additional, Pomat, Willie, additional, Mueller, Ivo, additional, Laman, Moses, additional, Freeman, Tim, additional, and Karl, Stephan, additional

Published
2020
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50. Strategies for understanding and reducing the Plasmodium vivax and Plasmodium ovale hypnozoite reservoir in Papua New Guinean children: a randomised placebo-controlled trial and mathematical model

Author

Robinson, Leanne J., Wampfler, Rahel, Betuela, Inoni, Karl, Stephan, White, Michael T., Suen, Connie S.N. Li Wai, Hofmann, Natalie E., Kinboro, Benson, Waltmann, Andreea, Brewster, Jessica, Lorry, Lina, Tarongka, Nandao, Samol, Lornah, Silkey, Mariabeth, Bassat, Quique, Siba, Peter M., Schofield, Louis, Felger, Ingrid, and Mueller, Ivo

Subjects
Primaquine -- Research -- Dosage and administration, Malaria -- Research -- Models -- Health aspects -- Drug therapy -- Patient outcomes -- Complications and side effects -- Development and progression, Biological sciences
Abstract

Background The undetectable hypnozoite reservoir for relapsing Plasmodium vivax and P. ovale malarias presents a major challenge for malaria control and elimination in endemic countries. This study aims to directly determine the contribution of relapses to the burden of P. vivax and P. ovale infection, illness, and transmission in Papua New Guinean children. Methods and Findings From 17 August 2009 to 20 May 2010,524 children aged 5-10 y from East Sepik Province in Papua New Guinea (PNG) participated in a randomised double-blind placebo-controlled trial of blood- plus liver-stage drugs (chloroquine [CQ], 3 d; artemether-lumefantrine [AL], 3 d; and primaquine [PQ], 20 d, 10 mg/kg total dose) (261 children) or blood-stage drugs only (CQ, 3 d; AL, 3 d; and placebo [PL], 20 d) (263 children). Participants, study staff, and investigators were blinded to the treatment allocation. Twenty children were excluded during the treatment phase (PQ arm: 14, PL arm: 6), and 504 were followed actively for 9 mo. During the follow-up time, 18 children (PQ arm: 7, PL arm: 11) were lost to follow-up. Main primary and secondary outcome measures were time to first P. vivax infection (by qPCR), time to first clinical episode, force of infection, gametocyte positivity, and time to first P. ovale infection (by PCR). A basic stochastic transmission model was developed to estimate the potential effect of mass drug administration (MDA) for the prevention of recurrent P. vivax infections. Targeting hypnozoites through PQ treatment reduced the risk of having at least one qPCR-detectable P. vivax or P. ovale infection during 8 mo of follow-up (P. vivax: PQ arm 0.63/y versus PL arm 2.62/y, HR = 0.18 [95% CI 0.14, 0.25], p < 0.001; P. ovale: 0.06 versus 0.14, HR = 0.31 [95% CI 0.13, 0.77], p = 0.011) and the risk of having at least one clinical P. vivax episode (HR = 0.25 [95% CI 0.11,0.61], p = 0.002). PQ also reduced the molecular force of P. vivax blood-stage infection in the first 3 mo of follow-up (PQ arm 1.90/y versus PL arm 7.75/y, incidence rate ratio [IRR] = 0.21 [95% CI 0.15,0.28], p < 0.001). Children who received PQ were less likely to carry P. vivax gametocytes (IRR = 0.27 [95% CI 0.19,0.38], p < 0.001). PQ had a comparable effect irrespective of the presence of P. vivax blood-stage infection at the time of treatment (p = 0.14). Modelling revealed that mass screening and treatment with highly sensitive quantitative real-time PCR, or MDA with blood-stage treatment alone, would have only a transient effect on P. vivax transmission levels, while MDA that includes liver-stage treatment is predicted to be a highly effective strategy for P. vivax elimination. The inclusion of a directly observed 20-d treatment regime maximises the efficiency of hypnozoite clearance but limits the generalisability of results to real-world MDA programmes. Conclusions These results suggest that relapses cause approximately four of every five P. vivax infections and at least three of every five P. ovale infections in PNG children and are important in sustaining transmission. MDA campaigns combining blood- and liver-stage treatment are predicted to be a highly efficacious intervention for reducing P. vivax and P. ovale transmission. Trial registration ClinicalTrials.gov NCT02143934, Introduction Renewed intensification of global malaria control efforts over the last 15 years have been successful in significantly reducing the global burden of malaria, with many countries in the Asia-Pacific [...]

Published
2015
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