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Mediavilla A, Silgado A, Febrer-Sendra B, Crego-Vicente B, Martínez-Vallejo P, Maturana CR, Goterris L, Nindia A, Martínez-Campreciós J, Aixut S, Aznar-Ruiz-de-Alegría ML, Fernández-Soto P, Muro A, Salvador F, Molina I, Berzosa P, Oliveira-Souto I, Sulleiro E. Real-time PCR for malaria diagnosis and identification of Plasmodium species in febrile patients in Cubal, Angola. Parasit Vectors 2024; 17:384. [PMID: 39261971 PMCID: PMC11389249 DOI: 10.1186/s13071-024-06467-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 08/24/2024] [Indexed: 09/13/2024] Open
Abstract
BACKGROUND Malaria is the parasitic disease with the highest morbimortality worldwide. The World Health Organization (WHO) estimates that there were approximately 249 million cases in 2022, of which 3.4% were in Angola. Diagnosis is based on parasite identification by microscopy examination, antigen detection, and/or molecular tests, such as polymerase chain reaction (PCR). This study aimed to evaluate the usefulness of real-time PCR as a diagnostic method for malaria in an endemic area (Cubal, Angola). METHODS A cross-sectional study was carried out at the Hospital Nossa Senhora da Paz in Cubal, Angola, including 200 patients who consulted for febrile syndrome between May and July 2022. From each patient, a capillary blood sample was obtained by finger prick for malaria field diagnosis [microscopy and rapid diagnostic test (RDT)] and venous blood sample for real-time PCR performed at the Hospital Universitario Vall d'Hebron in Barcelona, Spain. Any participant with a positive result from at least one of these three methods was diagnosed with malaria. RESULTS Of the 200 participants included, 54% were female and the median age was 7 years. Malaria was diagnosed by at least one of the three techniques (microscopy, RDT, and/or real-time PCR) in 58% of the participants, with RDT having the highest percentage of positivity (49%), followed by real-time PCR (39.5%) and microscopy (33.5%). Of the 61 discordant samples, 4 were only positive by microscopy, 13 by real-time PCR, and 26 by RDT. Plasmodium falciparum was the most frequent species detected (90.63%), followed by P. malariae (17.19%) and P. ovale (9.38%). Coinfections were detected in ten participants (15.63%): six (60%) were caused by P. falciparum and P. malariae, three (30%) by P. falciparum and P. ovale, and one (10%) triple infection with these three species. In addition, it was observed that P. falciparum and P. malariae coinfection significantly increased the parasite density of the latter. CONCLUSIONS RDT was the technique with the highest positivity rate, followed by real-time PCR and microscopy. The results of the real-time PCR may have been underestimated due to suboptimal storage conditions during the transportation of the DNA eluates. However, real-time PCR techniques have an important role in the surveillance of circulating Plasmodium species, given the epidemiological importance of the increase in non-falciparum species in the country, and can provide an estimate of the intensity of infection.
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Affiliation(s)
- Alejandro Mediavilla
- Microbiology Department, Vall d'Hebron University Hospital, Autonomous University of Barcelona, PROSICS Barcelona, Barcelona, Spain
- Universitat Autònoma de Barcelona (UAB), Barcelona, Spain
| | - Aroa Silgado
- Microbiology Department, Vall d'Hebron University Hospital, Autonomous University of Barcelona, PROSICS Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Begoña Febrer-Sendra
- Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Center for Research in Tropical Diseases of the University of Salamanca (IBSAL-CIETUS), Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Beatriz Crego-Vicente
- Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Center for Research in Tropical Diseases of the University of Salamanca (IBSAL-CIETUS), Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Patricia Martínez-Vallejo
- Microbiology Department, Vall d'Hebron University Hospital, Autonomous University of Barcelona, PROSICS Barcelona, Barcelona, Spain
- Universitat Autònoma de Barcelona (UAB), Barcelona, Spain
| | - Carles Rubio Maturana
- Microbiology Department, Vall d'Hebron University Hospital, Autonomous University of Barcelona, PROSICS Barcelona, Barcelona, Spain
- Universitat Autònoma de Barcelona (UAB), Barcelona, Spain
| | - Lidia Goterris
- Microbiology Department, Vall d'Hebron University Hospital, Autonomous University of Barcelona, PROSICS Barcelona, Barcelona, Spain
| | | | - Joan Martínez-Campreciós
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
- International Health Unit Vall d'Hebron-Drassanes, Infectious Diseases Department, Vall d'Hebron University Hospital, PROSICS Barcelona, Barcelona, Spain
| | - Sandra Aixut
- International Health Unit Vall d'Hebron-Drassanes, Infectious Diseases Department, Vall d'Hebron University Hospital, PROSICS Barcelona, Barcelona, Spain
| | - María Luisa Aznar-Ruiz-de-Alegría
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
- International Health Unit Vall d'Hebron-Drassanes, Infectious Diseases Department, Vall d'Hebron University Hospital, PROSICS Barcelona, Barcelona, Spain
| | - Pedro Fernández-Soto
- Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Center for Research in Tropical Diseases of the University of Salamanca (IBSAL-CIETUS), Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Antonio Muro
- Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Center for Research in Tropical Diseases of the University of Salamanca (IBSAL-CIETUS), Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Fernando Salvador
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
- International Health Unit Vall d'Hebron-Drassanes, Infectious Diseases Department, Vall d'Hebron University Hospital, PROSICS Barcelona, Barcelona, Spain
| | - Israel Molina
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
- International Health Unit Vall d'Hebron-Drassanes, Infectious Diseases Department, Vall d'Hebron University Hospital, PROSICS Barcelona, Barcelona, Spain
| | - Pedro Berzosa
- Malaria and Neglected Tropical Diseases Laboratory, National Centre for Tropical Medicine, Carlos III Health Institute, CIBER de Enfermedades Infecciosas, Madrid, Spain
| | - Inés Oliveira-Souto
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain.
- International Health Unit Vall d'Hebron-Drassanes, Infectious Diseases Department, Vall d'Hebron University Hospital, PROSICS Barcelona, Barcelona, Spain.
| | - Elena Sulleiro
- Microbiology Department, Vall d'Hebron University Hospital, Autonomous University of Barcelona, PROSICS Barcelona, Barcelona, Spain.
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain.
- International Health Unit Vall d'Hebron-Drassanes, Infectious Diseases Department, Vall d'Hebron University Hospital, PROSICS Barcelona, Barcelona, Spain.
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Frickmann H, Weinreich F, Loderstädt U, Poppert S, Tannich E, Bull J, Kreikemeyer B, Barrantes I. Metagenomic Sequencing for the Diagnosis of Plasmodium spp. with Different Levels of Parasitemia in EDTA Blood of Malaria Patients-A Proof-of-Principle Assessment. Int J Mol Sci 2022; 23:11150. [PMID: 36232449 PMCID: PMC9569645 DOI: 10.3390/ijms231911150] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 09/17/2022] [Accepted: 09/20/2022] [Indexed: 11/17/2022] Open
Abstract
Molecular diagnostic approaches are increasingly included in the diagnostic workup and even in the primary diagnosis of malaria in non-endemic settings, where it is difficult to maintain skillful microscopic malaria detection due to the rarity of the disease. Pathogen-specific nucleic acid amplification, however, bears the risk of overlooking other pathogens associated with febrile illness in returnees from the tropics. Here, we assessed the discriminatory potential of metagenomic sequencing for the identification of different Plasmodium species with various parasitemia in EDTA blood of malaria patients. Overall, the proportion of Plasmodium spp.-specific sequence reads in the assessed samples showed a robust positive correlation with parasitemia (Spearman r = 0.7307, p = 0.0001) and a robust negative correlation with cycle threshold (Ct) values of genus-specific real-time PCR (Spearman r = -0.8626, p ≤ 0.0001). Depending on the applied bioinformatic algorithm, discrimination on species level was successful in 50% (11/22) to 63.6% (14/22) instances. Limiting factors for the discrimination on species level were very low parasitemia, species-depending lacking availability of reliable reference genomes, and mixed infections with high variance of the proportion of the infecting species. In summary, metagenomic sequencing as performed in this study is suitable for the detection of malaria in human blood samples, but the diagnostic detection limit for a reliable discrimination on species level remains higher than for competing diagnostic approaches like microscopy and PCR.
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Affiliation(s)
- Hagen Frickmann
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Hamburg, 20359 Hamburg, Germany
- Institute for Medical Microbiology, Virology and Hygiene, University Medicine Rostock, 18057 Rostock, Germany
| | - Felix Weinreich
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Hamburg, 20359 Hamburg, Germany
| | - Ulrike Loderstädt
- Department of Hospital Hygiene & Infectious Diseases, University Medicine Göttingen, 37075 Goettingen, Germany
| | - Sven Poppert
- Bernhard Nocht Institute for Tropical Medicine Hamburg, 20359 Hamburg, Germany
| | - Egbert Tannich
- Bernhard Nocht Institute for Tropical Medicine Hamburg, 20359 Hamburg, Germany
| | - Jana Bull
- Institute for Medical Microbiology, Virology and Hygiene, University Medicine Rostock, 18057 Rostock, Germany
| | - Bernd Kreikemeyer
- Institute for Medical Microbiology, Virology and Hygiene, University Medicine Rostock, 18057 Rostock, Germany
| | - Israel Barrantes
- Research Group Translational Bioinformatics, Institute for Biostatistics and Informatics in Medicine und Aging Research, University Medicine Rostock, 18057 Rostock, Germany
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Aschar M, Sanchez MCA, Costa-Nascimento MDJ, Farinas MDLRN, Hristov AD, Lima GFMC, Inoue J, Levi JE, Di Santi SM. Ultrasensitive molecular tests for Plasmodium detection: applicability in control and elimination programs and reference laboratories. Rev Panam Salud Publica 2022; 46:e11. [PMID: 35355692 PMCID: PMC8959250 DOI: 10.26633/rpsp.2022.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 12/07/2021] [Indexed: 11/24/2022] Open
Abstract
Objective. To evaluate molecular tools to detect low-level parasitemia and the five species of Plasmodium that infect humans for use in control and elimination programs, and in reference laboratories. Methods. We evaluated 145 blood samples from patients who tested positive by nested polymerase chain reaction (nPCR), from asymptomatic individuals and from the WHO Global Malaria Programme/United Kingdom National External Quality Assessment Service. Samples were assayed using the genus-specific RealStar® Malaria PCR Kit 1.0 (alt-Gen; altona Diagnostics) and the RealStar® Malaria Screen & Type PCR Kit (alt-S&T; altona Diagnostics). The results from the molecular tests were compared with those from quantitative PCR (qPCR), nPCR and thick blood smear. Results. The levels of parasitemia ranged from 1 to 518 000 parasites/µL, depending on the species. Compared with nPCR, alt-S&T had a sensitivity of 100%, except for identifying P. falciparum, for which the sensitivity was 93.94%. All samples positive by alt-Gen were also positive by nPCR. When comparing alt-Gen to qPCR, the sensitivity was 100% for P. vivax, P. malariae and P. falciparum. For all Plasmodium species, the correlation between cycle threshold values of alt-S&T and alt-Gen compared with qPCR was significant (P < 0.0001, Spearman’s test), with r = 0.8621 for alt-S&T and r = 0.9371 for alt-Gen. When all Plasmodium species were considered, there was a negative correlation between the level of parasitemia and real-time PCR cycle threshold values (P < 0.0001). In this study, only 2 of 28 samples from asymptomatic individuals were positive by thick blood smear; however, all 28 of these samples were positive by alt-S&T. Conclusions. The alt-Gen and alt-S&T assays are suitable for detecting submicroscopic infections for distinct epidemiological purposes, such as for use in surveys and reference laboratories, and screening in blood banks, which will contribute to global efforts to eliminate malaria.
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Affiliation(s)
- Mariana Aschar
- Faculdade de Medicina Universidade de São Paulo São Paulo Brazil Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
| | - Maria Carmen A Sanchez
- Instituto de Medicina Tropical da Faculdade de Medicina da Universidade de São Paulo São Paulo Brazil Instituto de Medicina Tropical da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Maria de Jesus Costa-Nascimento
- Secretaria de Estado da Saúde de São Paulo/Instituto de Medicina Tropical da Faculdade de Medicina da Universidade de São Paulo São Paulo Brazil Secretaria de Estado da Saúde de São Paulo/Instituto de Medicina Tropical da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Maria de Lourdes R N Farinas
- Faculdade de Medicina Universidade de São Paulo São Paulo Brazil Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
| | - Angélica D Hristov
- Faculdade de Medicina Universidade de São Paulo São Paulo Brazil Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
| | - Giselle F M C Lima
- Faculdade de Medicina Universidade de São Paulo São Paulo Brazil Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
| | - Juliana Inoue
- Faculdade de Medicina Universidade de São Paulo São Paulo Brazil Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
| | - José E Levi
- Instituto de Medicina Tropical da Faculdade de Medicina da Universidade de São Paulo São Paulo Brazil Instituto de Medicina Tropical da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Silvia M Di Santi
- Secretaria de Estado da Saúde de São Paulo/Instituto de Medicina Tropical da Faculdade de Medicina da Universidade de São Paulo São Paulo Brazil Secretaria de Estado da Saúde de São Paulo/Instituto de Medicina Tropical da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
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Limited Reliability of the Molecular Detection of Plasmodium spp. from Incubated Blood Culture Samples for Forensic Purposes. Microorganisms 2022; 10:microorganisms10020406. [PMID: 35208861 PMCID: PMC8879611 DOI: 10.3390/microorganisms10020406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/06/2022] [Accepted: 02/08/2022] [Indexed: 12/10/2022] Open
Abstract
The suitability of incubated blood culture material for forensic molecular malaria diagnosis was assessed for non-endemic settings for cases in which the differential diagnosis malaria was initially overlooked. For the proof-of-principle assessment, residual blood culture materials from febrile patients from tropical Ghana were investigated by real-time PCR and compared with available historic microscopic results. In 2114 samples, for which microscopical results and real-time PCR results were available, microscopical results comprised 711 P. falciparum detections, 7 P. malariae detections, 1 microscopically not-further-discriminable Plasmodium spp. detection as well as 13 detections of mixed infections comprising 12 cases of P. falciparum/P. malariae co-infections and 1 case of a P. falciparum/P. ovale complex co-infection, while real-PCR indicated 558 P. falciparum detections, 95 P. malariae detections, 10 P. ovale complex detections, 1 P. vivax detection and 4 detected P. falciparum/P. malariae co-infections. Concordance of routine microscopy and real-time PCR was imperfect. Using routine microscopy as reference was associated with a seemingly low agreement of positive real-time PCR results of 90.9%. However, if positive samples, either by routine microscopy or real-time PCR or both, were applied as a combined reference, the agreement of positive results obtained with real-time PCR was increased from 74.0% to 77.9%, while the agreement of positive results obtained with routine microscopy was decreased from 100% to 85.3%. The predictive value of routine microscopy for negative results in the reference was slightly better with 90.9% compared to real-time PCR with 86.9%; the concordance between routine microscopy and real-time PCR was imperfect. In conclusion, even suboptimal sample materials such as incubated blood culture materials can be applied for forensic malaria diagnosis, if more suitable sample materials are not available, but the molecular detection rate of positive results in routine microscopy is much lower than previously reported for non-incubated blood.
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Mischlinger J, Manego RZ, Mombo-Ngoma G, Ekoka Mbassi D, Hackbarth N, Ekoka Mbassi FA, Davi SD, Kreuzmair R, Veletzky L, Hergeth J, Ndoumba WN, Pitzinger P, Groger M, Matsiegui PB, Adegnika AA, Agnandji ST, Lell B, Ramharter M. Diagnostic performance of capillary and venous blood samples in the detection of Loa loa and Mansonella perstans microfilaraemia using light microscopy. PLoS Negl Trop Dis 2021; 15:e0009623. [PMID: 34398886 PMCID: PMC8389422 DOI: 10.1371/journal.pntd.0009623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 08/26/2021] [Accepted: 07/03/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Loa loa and Mansonella perstans-the causative agents of loiasis and mansonellosis-are vector-borne filarial parasites co-endemic in sub-Saharan Africa. Diagnosis of both infections is usually established by microscopic analysis of blood samples. It was recently established that the odds for detecting Plasmodium spp. is higher in capillary (CAP) blood than in venous (VEN) blood. In analogy to this finding this analysis evaluates potential differences in microfilaraemia of L. loa and M. perstans in samples of CAP and VEN blood. METHODS Recruitment took place between 2015 and 2019 at the CERMEL in Lambaréné, Gabon and its surrounding villages. Persons of all ages presenting to diagnostic services of the research center around noon were invited to participate in the study. A thick smear of each 10 microliters of CAP and VEN blood was prepared and analysed by a minimum of two independent microscopists. Differences of log2-transformed CAP and VEN microfilaraemia were computed and expressed as percentages. Furthermore, odds ratios for paired data were computed to quantify the odds to detect microfilariae in CAP blood versus in VEN blood. RESULTS A total of 713 participants were recruited among whom 52% were below 30 years of age, 27% between 30-59 years of age and 21% above 60 years of age. Male-female ratio was 0.84. Among 152 participants with microscopically-confirmed L. loa infection median (IQR) microfilaraemia was 3,650 (275-11,100) per milliliter blood in CAP blood and 2,775 (200-8,875) in VEN blood (p<0.0001), while among 102 participants with M. perstans this was 100 (0-200) and 100 (0-200), respectively (p = 0.44). Differences in linear models amount up to an average of +34.5% (95% CI: +11.0 to +63.0) higher L. loa microfilaria quantity in CAP blood versus VEN blood and for M. perstans it was on average higher by +24.8% (95% CI: +0.0 to +60.5). Concordantly, the odds for detection of microfilaraemia in CAP samples versus VEN samples was 1.24 (95% CI: 0.65-2.34) and 1.65 (95% CI: 1.0-2.68) for infections with L. loa and M. perstans, respectively. CONCLUSION This analysis indicates that average levels of microfilaraemia of L. loa are higher in CAP blood samples than in VEN blood samples. This might have implications for treatment algorithms of onchocerciasis and loiasis, in which exact quantification of L. loa microfilaraemia is of importance. Furthermore, the odds for detection of M. perstans microfilariae was higher in CAP than in VEN blood which may pre-dispose CAP blood for detection of M. perstans infection in large epidemiological studies when sampling of large blood quantities is not feasible. No solid evidence for a higher odds of L. loa microfilariae detection in CAP blood was revealed, which might be explained by generally high levels of L. loa microfilaraemia in CAP and VEN blood above the limit of detection of 100 microfilariae/ml. Yet, it cannot be excluded that the study was underpowered to detect a moderate difference.
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Affiliation(s)
- Johannes Mischlinger
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Centre for Infection Research (DZIF), partner site Hamburg-Luebeck-Borstel, Hamburg, Germany
| | - Rella Zoleko Manego
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Centre for Infection Research (DZIF), partner site Hamburg-Luebeck-Borstel, Hamburg, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Ghyslain Mombo-Ngoma
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Centre for Infection Research (DZIF), partner site Hamburg-Luebeck-Borstel, Hamburg, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Dorothea Ekoka Mbassi
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Centre for Infection Research (DZIF), partner site Hamburg-Luebeck-Borstel, Hamburg, Germany
| | - Nina Hackbarth
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Centre for Infection Research (DZIF), partner site Hamburg-Luebeck-Borstel, Hamburg, Germany
| | - Franck-Aurelien Ekoka Mbassi
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Saskia Dede Davi
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Centre for Infection Research (DZIF), partner site Hamburg-Luebeck-Borstel, Hamburg, Germany
| | - Ruth Kreuzmair
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Luzia Veletzky
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Centre for Infection Research (DZIF), partner site Hamburg-Luebeck-Borstel, Hamburg, Germany
| | | | | | | | - Mirjam Groger
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Centre for Infection Research (DZIF), partner site Hamburg-Luebeck-Borstel, Hamburg, Germany
| | | | - Ayôla Akim Adegnika
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Germany
| | - Selidji Todagbe Agnandji
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany
| | - Bertrand Lell
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Michael Ramharter
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Centre for Infection Research (DZIF), partner site Hamburg-Luebeck-Borstel, Hamburg, Germany
- * E-mail:
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Abeje G, Gelaye W, Alemu G. Comparison of capillary, venous and buffy coat blood samples in detecting Plasmodium species among malaria suspected patients attending at Hamusite health center. A cross-sectional study. BMC Infect Dis 2021; 21:576. [PMID: 34130649 PMCID: PMC8204542 DOI: 10.1186/s12879-021-06290-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 06/04/2021] [Indexed: 11/10/2022] Open
Abstract
Background Both capillary and venous blood samples have been interchangeably used for the diagnosis of malaria in Ethiopia. However, Plasmodium parasites are thought to be more concentrated in capillary than in venous blood. Hence, selecting a sample source where parasites are more concentrated is indispensable approach in order to maximize the accuracy of blood film microscopy. Therefore, the present study aimed to compare the detection rate and the parasitemia level of Plasmodium species from conventional capillary and venous blood films, and buffy coat preparations. Methods A facility based cross-sectional study was conducted from Feburary to March 2020 among 210 febrile patients attending Hamusite health center, northwest Ethiopia. Capillary and venous blood samples were collected and buffy coat was prepared from each sample. Thin and thick blood films were prepared, stained, and examined microscopically following standard protocol. Data were analysed using Statistical Package for Social Sciences Software version 20 and Med-Calc software version 19.3. Results Capillary blood buffy coat (61/210, 29.0%) had significantly higher detection rate as compared to capillary (48/210, 22.9%) and venous (42/210, 20.0%) blood films (p < 0.001). However, no significant difference was observed between capillary and venous blood films (p = 0.070) in detecting Plasmodium species. The highest and the lowest mean asexual stage parasite counts were found in capillary blood buffy coat (4692.88) and venous blood (631.43) films, respectively showing significant variations (p < 0.001). Mean gametocyte count was also highest in capillary blood buffy coat (3958.44). As compared to capillary blood buffy coat, the sensitivity of venous blood buffy coat, capillary blood film and venous blood film were 73.8, 78.7, 68.9%, respectively. Conclusion Capillary blood buffy coat samples showed the highest sensitivity in detecting and quantitating malaria parasites that its use should be promoted in clinical settings. However, conventional capillary and venous blood films could be used interchangeably.
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Affiliation(s)
- Getu Abeje
- Department of Biomedcal Science, Samara University, Samara, Ethiopia
| | - Woyneshet Gelaye
- Department of Medical Laboratory Science, Bahir Dar University, Bahir Dar, Ethiopia
| | - Getaneh Alemu
- Department of Medical Laboratory Science, Bahir Dar University, Bahir Dar, Ethiopia.
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Leski TA, Taitt CR, Bangura U, Lahai J, Lamin JM, Baio V, Koroma MS, Swaray AG, Jacobsen KH, Jackson O, Jones BW, Phillips CL, Ansumana R, Stenger DA. Comparison of capillary and venous blood for malaria detection using two PCR-based assays in febrile patients in Sierra Leone. Malar J 2021; 20:133. [PMID: 33676502 PMCID: PMC7936501 DOI: 10.1186/s12936-021-03644-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 02/08/2021] [Accepted: 02/10/2021] [Indexed: 11/17/2022] Open
Abstract
Background Rapid and sensitive diagnostics are critical tools for clinical case management and public health control efforts. Both capillary and venous blood are currently used for malaria detection and while diagnostic technologies may not be equally sensitive with both materials, the published data on this subject are scarce and not conclusive. Methods Paired clinical samples of venous and capillary blood from 141 febrile individuals in Bo, Sierra Leone, were obtained between January and May 2019 and tested for the presence of Plasmodium parasites using two multiplexed PCR assays: the FilmArray-based Global Fever Panel (GFP) and the TaqMan-based Malaria Multiplex Sample Ready (MMSR) assay. Results No significant differences in Plasmodium parasite detection between capillary and venous blood for both assays were observed. The GFP assay was more sensitive than MMSR for all markers that could be compared (Plasmodium spp. and Plasmodium falciparum) in both venous and capillary blood. Conclusions No difference was found in malaria detection between venous and capillary blood using two different PCR-based detection assays. This data gives support for use of capillary blood, a material which can be obtained easier by less invasive methods, for PCR-based malaria diagnostics, independent of the platform.
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Affiliation(s)
- Tomasz A Leski
- Center for Bio/Molecular Science & Engineering, U.S. Naval Research Laboratory, Washington, DC, USA.
| | - Chris Rowe Taitt
- Center for Bio/Molecular Science & Engineering, U.S. Naval Research Laboratory, Washington, DC, USA
| | - Umaru Bangura
- Mercy Hospital Research Laboratory, Bo, Sierra Leone
| | - Joseph Lahai
- Mercy Hospital Research Laboratory, Bo, Sierra Leone
| | | | - Victoria Baio
- Mercy Hospital Research Laboratory, Bo, Sierra Leone
| | | | - Abdulai G Swaray
- College of Science, George Mason University, Fairfax, Virginia, USA
| | - Kathryn H Jacobsen
- Department of Global & Community Health, George Mason University, Fairfax, Virginia, USA
| | | | | | | | - Rashid Ansumana
- Mercy Hospital Research Laboratory, Bo, Sierra Leone.,Njala University, Bo, Sierra Leone
| | - David A Stenger
- Center for Bio/Molecular Science & Engineering, U.S. Naval Research Laboratory, Washington, DC, USA
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8
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Gorret AM, Muhindo R, Baguma E, Ntaro M, Mulogo EM, Deutsch-Feldman M, Juliano JJ, Nyehangane D, Boyce RM. Comparison of Capillary Versus Venous Blood for the Diagnosis of Plasmodium falciparum Malaria Using Rapid Diagnostic Tests. J Infect Dis 2021; 224:109-113. [PMID: 33502531 DOI: 10.1093/infdis/jiab032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 01/19/2021] [Indexed: 11/13/2022] Open
Abstract
We enrolled 250 febrile children in western Uganda to compare the results of malaria rapid diagnostic tests (RDTs) when using capillary vs venous blood. Participants were tested with 4 different RDT types. Polymerase chain reaction testing was performed as the reference standard. Sensitivity and specificity were broadly similar across RDT types and sampling method. Agreement between sample type was high, ranging from 0.95 to 0.99. When following the manufacturer's recommended interpretation, only 5 tests would have resulted in a different clinical diagnosis. These results demonstrate that malaria RDTs perform similarly when using capillary or venous blood in febrile children with Plasmodium falciparum malaria.
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Affiliation(s)
- Abalinda M Gorret
- Department of Medical Laboratory Science, Faculty of Medicine, Mbarara University of Science and Technology, Mbarara, Uganda
| | - Rabbison Muhindo
- Department of Community Health, Faculty of Medicine, Mbarara University of Science and Technology, Mbarara, Uganda
| | - Emma Baguma
- Department of Community Health, Faculty of Medicine, Mbarara University of Science and Technology, Mbarara, Uganda
| | - Moses Ntaro
- Department of Community Health, Faculty of Medicine, Mbarara University of Science and Technology, Mbarara, Uganda
| | - Edgar M Mulogo
- Department of Community Health, Faculty of Medicine, Mbarara University of Science and Technology, Mbarara, Uganda
| | - Molly Deutsch-Feldman
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Jonathan J Juliano
- Division of Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.,Curriculum in Genetics and Microbiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Dan Nyehangane
- Department of Medical Laboratory Science, Faculty of Medicine, Mbarara University of Science and Technology, Mbarara, Uganda.,Epicentre Mbarara Research Centre, Mbarara, Uganda
| | - Ross M Boyce
- Department of Community Health, Faculty of Medicine, Mbarara University of Science and Technology, Mbarara, Uganda.,Division of Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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9
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Pigeault R, Isaïa J, Yerbanga RS, Dabiré KR, Ouédraogo JB, Cohuet A, Lefèvre T, Christe P. Different distribution of malaria parasite in left and right extremities of vertebrate hosts translates into differences in parasite transmission. Sci Rep 2020; 10:10183. [PMID: 32576924 PMCID: PMC7311528 DOI: 10.1038/s41598-020-67180-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 06/04/2020] [Indexed: 11/16/2022] Open
Abstract
Malaria, a vector-borne disease caused by Plasmodium spp., remains a major global cause of mortality. Optimization of disease control strategies requires a thorough understanding of the processes underlying parasite transmission. While the number of transmissible stages (gametocytes) of Plasmodium in blood is frequently used as an indicator of host-to-mosquito transmission potential, this relationship is not always clear. Significant effort has been made in developing molecular tools that improve gametocyte density estimation and therefore prediction of mosquito infection rates. However a significant level of uncertainty around estimates remains. The weakness in the relationship between gametocyte burden, measured from a blood sample, and the mosquito infection rate could be explained by a non-homogeneous distribution of gametocytes in the bloodstream. The estimated gametocyte density would then only be a single snapshot that does not reflect the host infectivity. This aspect of Plasmodium infection, however, remains largely neglected. In both humans and birds, we found here that the gametocyte densities differed depending on which side of the body the sample was taken, suggesting that gametocytes are not homogeneously distributed within the vertebrate host. We observed a fluctuating asymmetry, in other words, the extremity of the body with the highest density of parasites is not always the same from one individual to another. An estimation of gametocyte density from only one blood sample, as is commonly measured, could, therefore, over- or underestimated the infectivity of gametocyte carriers. This might have important consequences on the epidemiology of the disease since we show that this variation influences host-to-mosquito transmission. Vectors fed on the least infected body part had a lower parasite burden than those fed on the most infected part. The heterogeneous distribution of gametocytes in bloodstream should be considered to improve diagnosis and test new malaria control strategies.
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Affiliation(s)
- Romain Pigeault
- Department of Ecology and Evolution, CH-1015, Lausanne, Switzerland.
| | - Julie Isaïa
- Department of Ecology and Evolution, CH-1015, Lausanne, Switzerland
| | | | - Kounbobr R Dabiré
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | | | - Anna Cohuet
- Unité MIVEGEC, IRD 224-CNRS 5290-Université Montpellier, Montpellier, France
| | - Thierry Lefèvre
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
- Unité MIVEGEC, IRD 224-CNRS 5290-Université Montpellier, Montpellier, France
| | - Philippe Christe
- Department of Ecology and Evolution, CH-1015, Lausanne, Switzerland
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10
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DNA recovery from archived RDTs for genetic characterization of Plasmodium falciparum in a routine setting in Lambaréné, Gabon. Malar J 2019; 18:336. [PMID: 31578142 PMCID: PMC6775649 DOI: 10.1186/s12936-019-2972-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 09/24/2019] [Indexed: 11/15/2022] Open
Abstract
Background Rapid diagnostic tests (RDTs) have been described as a source of genetic material to analyse malaria parasites in proof-of-concept studies. The increasing use of RDTs (e.g., in focal or mass screening and treatment campaigns) makes this approach particularly attractive for large-scale investigations of parasite populations. In this study, the complexity of Plasmodium falciparum infections, parasite load and chloroquine resistance transporter gene mutations were investigated in DNA samples extracted from positive RDTs, obtained in a routine setting and archived at ambient temperature. Methods A total of 669 archived RDTs collected from malaria cases in urban, semi-urban and rural areas of central Gabon were used for P. falciparum DNA extraction. Performance of RDTs as a source of DNA for PCR was determined using: (i) amplification of a single copy merozoite surface protein 1 (msp1) gene followed by highly sensitive and automated capillary electrophoresis; (ii) genotyping of the pfcrt gene locus 72–76 using haplotype-specific-probe-based real-time PCR to characterize chloroquine resistance; and, (iii) real-time PCR targeting 18S genes to detect and quantify Plasmodium parasites. Results Out of the 669 archived RDTs, amplification of P. falciparum nucleic materials had a success rate of 97% for 18S real-time PCR, and 88% for the msp1 gene. The multiplicity of infections (MOI) of the whole population was 2.6 (95% CI 2.5–2.8). The highest number of alleles detected in one infection was 11. The MOI decreased with increasing age (β = − 0.0046, p = 0.02) and residence in Lambaréné was associated with smaller MOIs (p < 0.001). The overall prevalence of mutations associated with chloroquine resistance was 78.5% and was not associated with age. In Lambaréné, prevalence of chloroquine resistance was lower compared to rural Moyen-Ogooué (β = − 0.809, p-value = 0.011). Conclusion RDT is a reliable source of DNA for P. falciparum detection and genotyping assays. Furthermore, the increasing use of RDTs allows them to be an alternative source of DNA for large-scale genetic epidemiological studies. Parasite populations in the study area are highly diverse and prevalence of chloroquine-resistant P. falciparum remains high, especially in rural areas.
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11
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Frickmann H, Wegner C, Ruben S, Behrens C, Kollenda H, Hinz R, Rojak S, Schwarz NG, Hagen RM, Tannich E. Evaluation of the multiplex real-time PCR assays RealStar malaria S&T PCR kit 1.0 and FTD malaria differentiation for the differentiation of Plasmodium species in clinical samples. Travel Med Infect Dis 2019; 31:101442. [PMID: 31255712 DOI: 10.1016/j.tmaid.2019.06.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 06/20/2019] [Accepted: 06/26/2019] [Indexed: 12/28/2022]
Abstract
BACKGROUND Two commercial PCR assays were assessed in a retrospective study to determine their reliability as tools for the differentiation of Plasmodium species in human blood. METHODS A total of 1022 blood samples from 817 patients with suspected or confirmed malaria submitted to the German National Reference Centre for Tropical Pathogens were subjected to malaria microscopy using thick and thin blood films as well as to a genus-specific malaria real-time PCR. Parasite-positive samples were analysed by RealStar Malaria S&T PCR Kit 1.0 (altona Diagnostics) and FTD Malaria Differentiation (Fast Track Diagnostics) multiplex real-time PCR assays targeting species-specific Plasmodium DNA. RESULTS Out of the 1022 blood samples, 247 (24.2%) tested positive for Plasmodium spp. The two multiplex assays showed rather similar performance characteristics and provided concordant species information in 98.9% of samples positive by malaria microscopy and in 95.1% (RealStar) and 96.8% (FTD) of samples positive by genus-specific PCR. Compared to FTD, RealStar revealed slightly reduced sensitivity for submicroscopic, low-level P. falciparum infections, while FTD was unable to detect P. knowlesi. CONCLUSIONS The two commercial malaria PCR assays assessed are suitable for discriminating Plasmodium species in clinical samples, and can provide additional information in cases of microscopically uncertain findings.
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Affiliation(s)
- Hagen Frickmann
- Department of Microbiology and Hospital Hygiene, Tropical Microbiology and Entomology Unit, Bundeswehr Hospital Hamburg, Hamburg, Germany; Institute for Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany.
| | - Christine Wegner
- National Reference Centre for Tropical Pathogens, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Stefanie Ruben
- National Reference Centre for Tropical Pathogens, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Christoph Behrens
- National Reference Centre for Tropical Pathogens, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Hans Kollenda
- Department of Microbiology and Hospital Hygiene, Tropical Microbiology and Entomology Unit, Bundeswehr Hospital Hamburg, Hamburg, Germany
| | - Rebecca Hinz
- Department of Microbiology and Hospital Hygiene, Tropical Microbiology and Entomology Unit, Bundeswehr Hospital Hamburg, Hamburg, Germany
| | - Sandra Rojak
- Department of Microbiology and Hospital Hygiene, Tropical Microbiology and Entomology Unit, Bundeswehr Hospital Hamburg, Hamburg, Germany; Department of Infectious Diseases and Tropical Medicine, Bundeswehr Hospital Hamburg, Hamburg, Germany
| | - Norbert G Schwarz
- Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Ralf Matthias Hagen
- Department of Preventive Medicine, Bundeswehr Medical Academy, Munich, Germany
| | - Egbert Tannich
- National Reference Centre for Tropical Pathogens, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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12
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Lehane A, Were M, Wade M, Hamadu M, Cahill M, Kiconco S, Kajubi R, Aweeka F, Mwebaza N, Li F, Parikh S. Comparison on simultaneous caillary and venous parasite density and genotyping results from children and adults with uncomplicated malaria: a prospective observational study in Uganda. BMC Infect Dis 2019; 19:559. [PMID: 31242863 PMCID: PMC6595677 DOI: 10.1186/s12879-019-4174-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 06/09/2019] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Blood smear microscopy remains the gold-standard method to diagnose and quantify malaria parasite density. In addition, parasite genotyping of select loci is the most utilized method for distinguishing recrudescent and new infections and to determine the number of strains per sample. In research settings, blood may be obtained from capillary or venous compartments, and results from these matrices have been used interchangeably. Our aim was to compare quantitative results for parasite density and strain complexity from both compartments. METHODS In a prospective observational study, children and adults presenting with uncomplicated Plasmodium falciparum malaria, simultaneous capillary and venous blood smears and dried blood spots were collected over 42-days following treatment with artemether-lumefantrine. Blood smears were read by two microscopists, any discrepancies resolved by a third reader. Parasite DNA fingerprinting was conducted using six microsatellites. Bland Altman analysis and paired t-test/McNemar's test were used to assess the difference in density readings and measurements. RESULTS Two hundred twenty-three participants were included in the analysis (177 children (35 HIV-infected/142 HIV-uninfected), 21 HIV-uninfected pregnant women, and 25 HIV-uninfected non-pregnant adults). Parasite density measurements did not statistically differ between capillary and venous blood smears at the time of presentation, nor over the course of 42-day follow-up. Characterization of merozoite surface protein-2 (MSP-2) genetic polymorphism demonstrated a higher level of strain diversity at the time of presentation in venous samples, as compared with capillary specimens (p = 0.02). There was a high degree of variability in genotype-corrected outcomes when pairs of samples from each compartment were compared using MSP-2 alone, although the variability was reduced with the use of multiple markers. CONCLUSIONS Parasite density measurements do not statistically differ between capillary and venous compartments in all studied demographic groups at the time of presentation with malaria, or over the course of follow-up. More strains were detected by MSP-2 genotyping in venous samples than in capillary samples at the time of malaria diagnosis. The use of multiple polymorphic markers reduces the impact of variability in strain detection on genotype-corrected outcomes. This study confirms that both capillary and venous compartments can be used for sampling with confidence in the clinical research setting. TRIAL REGISTRATION The trial was registered at ClinicalTrials.gov under registration no. NCT01717885 .
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Affiliation(s)
- Aine Lehane
- Yale School of Public Health, New Haven, CT USA
| | - Moses Were
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | | | | | - Sylvia Kiconco
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Richard Kajubi
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Norah Mwebaza
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Fangyong Li
- Yale School of Public Health, New Haven, CT USA
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13
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Mischlinger J, Pitzinger P, Veletzky L, Groger M, Zoleko-Manego R, Adegnika AA, Agnandji ST, Lell B, Kremsner PG, Mombo-Ngoma G, Mordmüller B, Ramharter M. Validity and reliability of methods to microscopically detect and quantify malaria parasitaemia. Trop Med Int Health 2018; 23:980-991. [PMID: 29956431 DOI: 10.1111/tmi.13124] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES The recommended microscopy method by WHO to quantify malaria parasitaemia yields inaccurate results when individual leucocyte (WBC) counts deviate from 8000 leucocytes/μl. A method avoiding WBC count assumptions is the Lambaréné method (LAMBA). Thus, this study compared validity and reliability of the LAMBA and the WHO method. METHODS Three methods for counting parasitaemia were applied in parallel in a blinded assessment: the LAMBA, the WHO method using a standard factor of 8000 leucocytes/μl ['simple WHO method' (sWHO)] and the WHO method using measured WBC counts ['accurate WHO method' (aWHO)]. Validity was assessed by comparing LAMBA and sWHO to the gold standard measurement of aWHO. Reliability was ascertained by computation of intraclass correlation coefficients (ICCs). RESULTS 787 malaria-positive thick smears were analysed. Parasitaemia as determined by LAMBA and sWHO increasingly deviated from aWHO the more patients' WBCs diverged from 8000/μl. Equations of linear regression models assessing method deviation in percent from gold standard as function of WBC count were y = -0.00608x (95% CI -0.00693 to -0.00524) + 47.8 for LAMBA and y = -0.0125x (95% CI -0.01253 to -0.01247) + 100.1 for sWHO. Comparison of regression slopes showed that the deviation was twice as high for sWHO as for LAMBA (P < 0.001). ICCs were excellent (>90%) for both methods. CONCLUSIONS The LAMBA has higher validity than the sWHO and may therefore be preferable in resource-limited settings without access to routine WBC-evaluation.
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Affiliation(s)
- Johannes Mischlinger
- Division of Infectious Diseases and Tropical Medicine, Department of Medicine I, Medical University of Vienna, Vienna, Austria.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, German Centre for Infection Research, partner site Tübingen, Universität Tübingen, Tübingen, Germany.,Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Paul Pitzinger
- Division of Infectious Diseases and Tropical Medicine, Department of Medicine I, Medical University of Vienna, Vienna, Austria.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Luzia Veletzky
- Division of Infectious Diseases and Tropical Medicine, Department of Medicine I, Medical University of Vienna, Vienna, Austria.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Mirjam Groger
- Division of Infectious Diseases and Tropical Medicine, Department of Medicine I, Medical University of Vienna, Vienna, Austria.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Rella Zoleko-Manego
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, German Centre for Infection Research, partner site Tübingen, Universität Tübingen, Tübingen, Germany.,Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ayola A Adegnika
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, German Centre for Infection Research, partner site Tübingen, Universität Tübingen, Tübingen, Germany
| | - Selidji T Agnandji
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, German Centre for Infection Research, partner site Tübingen, Universität Tübingen, Tübingen, Germany
| | - Bertrand Lell
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, German Centre for Infection Research, partner site Tübingen, Universität Tübingen, Tübingen, Germany
| | - Peter G Kremsner
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, German Centre for Infection Research, partner site Tübingen, Universität Tübingen, Tübingen, Germany
| | - Ghyslain Mombo-Ngoma
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, German Centre for Infection Research, partner site Tübingen, Universität Tübingen, Tübingen, Germany.,Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Malaria Clinical and Operational Research Unit, Melen Hospital, Département de Parasitology, Université des Sciences de la Santé Gabon, Libreville, Gabon
| | - Benjamin Mordmüller
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, German Centre for Infection Research, partner site Tübingen, Universität Tübingen, Tübingen, Germany
| | - Michael Ramharter
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,German Centre for Infection Research (DZIF), partner site Hamburg-Luebeck-Borstel, Hamburg, Germany
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