Comparison of three methods for detection of gametocytes in Melanesian children treated for uncomplicated malaria

Stephan Karl; Moses Laman; Tamarah Koleala; Clemencia Ibam; Bernadine Kasian; Nola N'Drewei; Anna Rosanas-Urgell; Brioni R Moore; Andreea Waltmann; Cristian Koepfli; Peter M Siba; Inoni Betuela; Robert C Woodward; Timothy G St Pierre; Ivo Mueller; Timothy M E Davis

doi:10.1186/1475-2875-13-319

Comparison of three methods for detection of gametocytes in Melanesian children treated for uncomplicated malaria

Stephan Karl, Moses Laman, Tamarah Koleala, Clemencia Ibam, Bernadine Kasian, Nola N'Drewei, Anna Rosanas-Urgell, Brioni R Moore, Andreea Waltmann, Cristian Koepfli, Peter M Siba, Inoni Betuela, Robert C Woodward, Timothy G St Pierre, Ivo Mueller, Timothy M E Davis

Malariology

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Abstract

BACKGROUND: Gametocytes are the transmission stages of Plasmodium parasites, the causative agents of malaria. As their density in the human host is typically low, they are often undetected by conventional light microscopy. Furthermore, application of RNA-based molecular detection methods for gametocyte detection remains challenging in remote field settings. In the present study, a detailed comparison of three methods, namely light microscopy, magnetic fractionation and reverse transcriptase polymerase chain reaction for detection of Plasmodium falciparum and Plasmodium vivax gametocytes was conducted.

METHODS: Peripheral blood samples from 70 children aged 0.5 to five years with uncomplicated malaria who were treated with either artemether-lumefantrine or artemisinin-naphthoquine were collected from two health facilities on the north coast of Papua New Guinea. The samples were taken prior to treatment (day 0) and at pre-specified intervals during follow-up. Gametocytes were measured in each sample by three methods: i) light microscopy (LM), ii) quantitative magnetic fractionation (MF) and, iii) reverse transcriptase PCR (RTPCR). Data were analysed using censored linear regression and Bland and Altman techniques.

RESULTS: MF and RTPCR were similarly sensitive and specific, and both were superior to LM. Overall, there were approximately 20% gametocyte-positive samples by LM, whereas gametocyte positivity by MF and RTPCR were both more than two-fold this level. In the subset of samples collected prior to treatment, 29% of children were positive by LM, and 85% were gametocyte positive by MF and RTPCR, respectively.

CONCLUSIONS: The present study represents the first direct comparison of standard LM, MF and RTPCR for gametocyte detection in field isolates. It provides strong evidence that MF is superior to LM and can be used to detect gametocytaemic patients under field conditions with similar sensitivity and specificity as RTPCR.

Original language	English
Journal	Malaria Journal
Volume	13
Pages (from-to)	319
ISSN	1475-2875
DOIs	https://doi.org/10.1186/1475-2875-13-319
Publication status	Published - 2014

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10.1186/1475-2875-13-319Licence: CC BY

2014mjou0319Final published version, 493 KBLicence: CC BY

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Karl, S., Laman, M., Koleala, T., Ibam, C., Kasian, B., N'Drewei, N., Rosanas-Urgell, A., Moore, B. R., Waltmann, A., Koepfli, C., Siba, P. M., Betuela, I., Woodward, R. C., St Pierre, T. G., Mueller, I., & Davis, T. M. E. (2014). Comparison of three methods for detection of gametocytes in Melanesian children treated for uncomplicated malaria. Malaria Journal, 13, 319. https://doi.org/10.1186/1475-2875-13-319

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title = "Comparison of three methods for detection of gametocytes in Melanesian children treated for uncomplicated malaria",

abstract = "BACKGROUND: Gametocytes are the transmission stages of Plasmodium parasites, the causative agents of malaria. As their density in the human host is typically low, they are often undetected by conventional light microscopy. Furthermore, application of RNA-based molecular detection methods for gametocyte detection remains challenging in remote field settings. In the present study, a detailed comparison of three methods, namely light microscopy, magnetic fractionation and reverse transcriptase polymerase chain reaction for detection of Plasmodium falciparum and Plasmodium vivax gametocytes was conducted.METHODS: Peripheral blood samples from 70 children aged 0.5 to five years with uncomplicated malaria who were treated with either artemether-lumefantrine or artemisinin-naphthoquine were collected from two health facilities on the north coast of Papua New Guinea. The samples were taken prior to treatment (day 0) and at pre-specified intervals during follow-up. Gametocytes were measured in each sample by three methods: i) light microscopy (LM), ii) quantitative magnetic fractionation (MF) and, iii) reverse transcriptase PCR (RTPCR). Data were analysed using censored linear regression and Bland and Altman techniques.RESULTS: MF and RTPCR were similarly sensitive and specific, and both were superior to LM. Overall, there were approximately 20% gametocyte-positive samples by LM, whereas gametocyte positivity by MF and RTPCR were both more than two-fold this level. In the subset of samples collected prior to treatment, 29% of children were positive by LM, and 85% were gametocyte positive by MF and RTPCR, respectively.CONCLUSIONS: The present study represents the first direct comparison of standard LM, MF and RTPCR for gametocyte detection in field isolates. It provides strong evidence that MF is superior to LM and can be used to detect gametocytaemic patients under field conditions with similar sensitivity and specificity as RTPCR.",

keywords = "Antimalarials, Artemisinins, Child, Preschool, Clinical Laboratory Techniques, Drug Combinations, Ethanolamines, Female, Fluorenes, Humans, Immunomagnetic Separation, Infant, Malaria, Male, Microscopy, Naphthoquinones, Papua New Guinea, Parasitology, Plasmodium falciparum, Plasmodium vivax, Reverse Transcriptase Polymerase Chain Reaction, Sensitivity and Specificity",

author = "Stephan Karl and Moses Laman and Tamarah Koleala and Clemencia Ibam and Bernadine Kasian and Nola N'Drewei and Anna Rosanas-Urgell and Moore, {Brioni R} and Andreea Waltmann and Cristian Koepfli and Siba, {Peter M} and Inoni Betuela and Woodward, {Robert C} and {St Pierre}, {Timothy G} and Ivo Mueller and Davis, {Timothy M E}",

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year = "2014",

doi = "10.1186/1475-2875-13-319",

language = "English",

volume = "13",

pages = "319",

journal = "Malaria Journal",

issn = "1475-2875",

publisher = "BioMed Central",

}

Karl, S, Laman, M, Koleala, T, Ibam, C, Kasian, B, N'Drewei, N, Rosanas-Urgell, A, Moore, BR, Waltmann, A, Koepfli, C, Siba, PM, Betuela, I, Woodward, RC, St Pierre, TG, Mueller, I & Davis, TME 2014, 'Comparison of three methods for detection of gametocytes in Melanesian children treated for uncomplicated malaria', Malaria Journal, vol. 13, pp. 319. https://doi.org/10.1186/1475-2875-13-319

TY - JOUR

T1 - Comparison of three methods for detection of gametocytes in Melanesian children treated for uncomplicated malaria

AU - Karl, Stephan

AU - Laman, Moses

AU - Koleala, Tamarah

AU - Ibam, Clemencia

AU - Kasian, Bernadine

AU - N'Drewei, Nola

AU - Rosanas-Urgell, Anna

AU - Moore, Brioni R

AU - Waltmann, Andreea

AU - Koepfli, Cristian

AU - Siba, Peter M

AU - Betuela, Inoni

AU - Woodward, Robert C

AU - St Pierre, Timothy G

AU - Mueller, Ivo

AU - Davis, Timothy M E

N1 - FTX

PY - 2014

Y1 - 2014

N2 - BACKGROUND: Gametocytes are the transmission stages of Plasmodium parasites, the causative agents of malaria. As their density in the human host is typically low, they are often undetected by conventional light microscopy. Furthermore, application of RNA-based molecular detection methods for gametocyte detection remains challenging in remote field settings. In the present study, a detailed comparison of three methods, namely light microscopy, magnetic fractionation and reverse transcriptase polymerase chain reaction for detection of Plasmodium falciparum and Plasmodium vivax gametocytes was conducted.METHODS: Peripheral blood samples from 70 children aged 0.5 to five years with uncomplicated malaria who were treated with either artemether-lumefantrine or artemisinin-naphthoquine were collected from two health facilities on the north coast of Papua New Guinea. The samples were taken prior to treatment (day 0) and at pre-specified intervals during follow-up. Gametocytes were measured in each sample by three methods: i) light microscopy (LM), ii) quantitative magnetic fractionation (MF) and, iii) reverse transcriptase PCR (RTPCR). Data were analysed using censored linear regression and Bland and Altman techniques.RESULTS: MF and RTPCR were similarly sensitive and specific, and both were superior to LM. Overall, there were approximately 20% gametocyte-positive samples by LM, whereas gametocyte positivity by MF and RTPCR were both more than two-fold this level. In the subset of samples collected prior to treatment, 29% of children were positive by LM, and 85% were gametocyte positive by MF and RTPCR, respectively.CONCLUSIONS: The present study represents the first direct comparison of standard LM, MF and RTPCR for gametocyte detection in field isolates. It provides strong evidence that MF is superior to LM and can be used to detect gametocytaemic patients under field conditions with similar sensitivity and specificity as RTPCR.

AB - BACKGROUND: Gametocytes are the transmission stages of Plasmodium parasites, the causative agents of malaria. As their density in the human host is typically low, they are often undetected by conventional light microscopy. Furthermore, application of RNA-based molecular detection methods for gametocyte detection remains challenging in remote field settings. In the present study, a detailed comparison of three methods, namely light microscopy, magnetic fractionation and reverse transcriptase polymerase chain reaction for detection of Plasmodium falciparum and Plasmodium vivax gametocytes was conducted.METHODS: Peripheral blood samples from 70 children aged 0.5 to five years with uncomplicated malaria who were treated with either artemether-lumefantrine or artemisinin-naphthoquine were collected from two health facilities on the north coast of Papua New Guinea. The samples were taken prior to treatment (day 0) and at pre-specified intervals during follow-up. Gametocytes were measured in each sample by three methods: i) light microscopy (LM), ii) quantitative magnetic fractionation (MF) and, iii) reverse transcriptase PCR (RTPCR). Data were analysed using censored linear regression and Bland and Altman techniques.RESULTS: MF and RTPCR were similarly sensitive and specific, and both were superior to LM. Overall, there were approximately 20% gametocyte-positive samples by LM, whereas gametocyte positivity by MF and RTPCR were both more than two-fold this level. In the subset of samples collected prior to treatment, 29% of children were positive by LM, and 85% were gametocyte positive by MF and RTPCR, respectively.CONCLUSIONS: The present study represents the first direct comparison of standard LM, MF and RTPCR for gametocyte detection in field isolates. It provides strong evidence that MF is superior to LM and can be used to detect gametocytaemic patients under field conditions with similar sensitivity and specificity as RTPCR.

KW - Antimalarials

KW - Artemisinins

KW - Child, Preschool

KW - Clinical Laboratory Techniques

KW - Drug Combinations

KW - Ethanolamines

KW - Female

KW - Fluorenes

KW - Humans

KW - Immunomagnetic Separation

KW - Infant

KW - Malaria

KW - Male

KW - Microscopy

KW - Naphthoquinones

KW - Papua New Guinea

KW - Parasitology

KW - Plasmodium falciparum

KW - Plasmodium vivax

KW - Reverse Transcriptase Polymerase Chain Reaction

KW - Sensitivity and Specificity

U2 - 10.1186/1475-2875-13-319

DO - 10.1186/1475-2875-13-319

M3 - A1: Web of Science-article

C2 - 25123055

SN - 1475-2875

VL - 13

SP - 319

JO - Malaria Journal

JF - Malaria Journal

ER -

Comparison of three methods for detection of gametocytes in Melanesian children treated for uncomplicated malaria

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