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Watson JA, Uyoga S, Wanjiku P, Makale J, Nyutu GM, Mturi N, George EC, Woodrow CJ, Day NPJ, Bejon P, Opoka RO, Dondorp AM, John CC, Maitland K, Williams TN, White NJ. Improving the diagnosis of severe malaria in African children using platelet counts and plasma PfHRP2 concentrations. Sci Transl Med 2022; 14:eabn5040. [PMID: 35857826 PMCID: PMC7613613 DOI: 10.1126/scitranslmed.abn5040] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Severe malaria caused by Plasmodium falciparum is difficult to diagnose accurately in children in high-transmission settings. Using data from 2649 pediatric and adult patients enrolled in four studies of severe illness in three countries (Bangladesh, Kenya, and Uganda), we fitted Bayesian latent class models using two diagnostic markers: the platelet count and the plasma concentration of P. falciparum histidine-rich protein 2 (PfHRP2). In severely ill patients with clinical features consistent with severe malaria, the combination of a platelet count of ≤150,000/μl and a plasma PfHRP2 concentration of ≥1000 ng/ml had an estimated sensitivity of 74% and specificity of 93% in identifying severe falciparum malaria. Compared with misdiagnosed children, pediatric patients with true severe malaria had higher parasite densities, lower hematocrits, lower rates of invasive bacterial disease, and a lower prevalence of both sickle cell trait and sickle cell anemia. We estimate that one-third of the children enrolled into clinical studies of severe malaria in high-transmission settings in Africa had another cause of their severe illness.
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Affiliation(s)
- James A. Watson
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK,Corresponding author.
| | - Sophie Uyoga
- KEMRI Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Coast, Kilifi 80108, Kenya
| | - Perpetual Wanjiku
- KEMRI Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Coast, Kilifi 80108, Kenya
| | - Johnstone Makale
- KEMRI Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Coast, Kilifi 80108, Kenya
| | - Gideon M. Nyutu
- KEMRI Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Coast, Kilifi 80108, Kenya
| | - Neema Mturi
- KEMRI Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Coast, Kilifi 80108, Kenya
| | - Elizabeth C. George
- Medical Research Council Clinical Trials Unit, University College London, London, UK
| | - Charles J. Woodrow
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Nicholas P. J. Day
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Philip Bejon
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK,KEMRI Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Coast, Kilifi 80108, Kenya
| | - Robert O. Opoka
- Makerere University, Department of Paediatrics and Child Health, Kampala, Uganda
| | - Arjen M. Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Chandy C. John
- Department of Pediatrics, Indiana University, Indiana, IN, USA
| | - Kathryn Maitland
- KEMRI Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Coast, Kilifi 80108, Kenya,Institute of Global Health Innovation, Department of Surgery and Cancer, Imperial College, London, UK
| | - Thomas N. Williams
- KEMRI Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Coast, Kilifi 80108, Kenya,Institute of Global Health Innovation, Department of Surgery and Cancer, Imperial College, London, UK
| | - Nicholas J. White
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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Uyoga S, Wanjiku P, Rop JC, Makale J, Macharia AW, Nyutu GM, Shebe M, Awuondo KA, Mturi N, Woodrow CJ, Dondorp AM, Maitland K, Williams TN. Plasma Plasmodium falciparum Histidine-Rich Protein-2 concentrations in children with malaria infections of differing severity in Kilifi, Kenya. Clin Infect Dis 2020; 73:e2415-e2423. [PMID: 32772115 PMCID: PMC8492128 DOI: 10.1093/cid/ciaa1141] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Indexed: 11/13/2022] Open
Abstract
Background Most previous studies support a direct link between total parasite load and the clinical severity of Plasmodium falciparum malaria infections. Methods We estimated P. falciparum parasite loads in 3 groups of children with malaria infections of differing severity: (1) children with World Health Organization–defined severe malaria (n = 1544), (2) children admitted with malaria but without features of severity (n = 200), and (3) children in the community with asymptomatic parasitemia (n = 33). Results Peripheral parasitemias were highest in those with uncomplicated malaria (geometric mean [GM] parasite count, 111 064/μL; 95% confidence interval, CI, 86 798–141 819/μL), almost 3 times higher than in those with severe malaria (39 588/μL; 34 990–44 791/μL) and >100 times higher than in those with asymptomatic malaria (1092/μL; 523–2280/μL). However, the GM P. falciparum histidine-rich protein 2 (PfHRP2) values (95% CI) increased with severity, being 7 (4–12) ng/mL in asymptomatic malaria, 843 (655–1084) ng/mL in uncomplicated malaria, and 1369 (1244–1506) ng/mL in severe malaria. PfHRP2 concentrations were markedly lower in the subgroup of patients with severe malaria and concomitant invasive bacterial infections of blood or cerebrospinal fluid (GM concentration, 312 ng/mL; 95% CI, 175–557 ng/mL; P < .001) than in those without such infections (1439 ng/mL; 1307–1584; P < .001). Conclusions The clinical severity of malaria infections related strongly to the total burden of P. falciparum parasites. A quantitative test for plasma concentrations of PfHRP2 could be useful in identifying children at the greatest clinical risk and identifying critically ill children in whom malaria is not the primary cause.
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Affiliation(s)
- Sophie Uyoga
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Jesse C Rop
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | | | | | | | - Neema Mturi
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Charles J Woodrow
- Mahidol-Oxford Research Unit,Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health,Nuffield Department of Medicine,University of Oxford, UK
| | - Arjen M Dondorp
- Mahidol-Oxford Research Unit,Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health,Nuffield Department of Medicine,University of Oxford, UK
| | - Kathryn Maitland
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Department of Infectious Diseases, Imperial College, London, UK
| | - Thomas N Williams
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Department of Infectious Diseases, Imperial College, London, UK
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