Misidentification of Plasmodium ovale as Plasmodium vivax malaria by a microscopic method: a meta-analysis of confirmed P. ovale cases

Abstract Plasmodium ovale is a benign tertian malaria parasite that morphologically resembles Plasmodium vivax. P. ovale also shares similar tertian periodicity and can cause relapse in patients without a radical cure, making it easily misidentified as P. vivax in routine diagnosis. Therefore, its p...

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Main Authors: Manas Kotepui, Frederick Ramirez Masangkay, Kwuntida Uthaisar Kotepui, Giovanni De Jesus Milanez
Format: Article
Language:English
Published: Nature Portfolio 2020-12-01
Series:Scientific Reports
Online Access:https://doi.org/10.1038/s41598-020-78691-7
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author Manas Kotepui
Frederick Ramirez Masangkay
Kwuntida Uthaisar Kotepui
Giovanni De Jesus Milanez
author_facet Manas Kotepui
Frederick Ramirez Masangkay
Kwuntida Uthaisar Kotepui
Giovanni De Jesus Milanez
author_sort Manas Kotepui
collection DOAJ
description Abstract Plasmodium ovale is a benign tertian malaria parasite that morphologically resembles Plasmodium vivax. P. ovale also shares similar tertian periodicity and can cause relapse in patients without a radical cure, making it easily misidentified as P. vivax in routine diagnosis. Therefore, its prevalence might be underreported worldwide. The present study aimed to quantify the prevalence of P. ovale misidentified as P. vivax malaria using data from studies reporting confirmed P. ovale cases by molecular methods. Studies reporting the misidentification of P. ovale as P. vivax malaria were identified from three databases, MEDLINE, Web of Science, and Scopus, without language restrictions, but the publication date was restricted to 1993 and 2020. The quality of the included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS). The random-effects model was used to estimate the pooled prevalence of the misidentification of P. ovale as P. vivax malaria by the microscopic method when compared to those with the reference polymerase chain reaction method. Subgroup analysis of participants was also performed to demonstrate the difference between imported and indigenous P. ovale cases. The heterogeneity of the included studies was assessed using Cochran's Q and I2 statistics. Publication bias across the included studies was assessed using the funnel plot and Egger’s test, and if required, contour-enhanced funnel plots were used to identify the source(s) of funnel plot asymmetry. Of 641 articles retrieved from databases, 22 articles met the eligibility criteria and were included in the present study. Of the 8,297 malaria-positive cases identified by the PCR method, 453 P. ovale cases were confirmed. The pooled prevalence of misidentification of P. ovale as P. vivax malaria by the microscopic method was 11% (95% CI: 7–14%, I2: 25.46%). Subgroup analysis of the participants demonstrated a higher prevalence of misidentification in indigenous cases (13%, 95% CI: 6–21%, I2: 27.8%) than in imported cases (10%, 95% CI: 6–14%, I2: 24.1%). The pooled prevalence of misidentification of P. vivax as P. ovale malaria by the microscopic method was 1%, without heterogeneity (95% CI: 0–3%, I2: 16.8%). PCR was more sensitive in identifying P. ovale cases than the microscopic method (p < 0.00001, OR: 2.76, 95% CI: 1.83–4.15, I2: 65%). Subgroup analysis of participants demonstrated the better performance of PCR in detecting P. ovale malaria in indigenous cases (p: 0.0009, OR: 6.92, 95% CI: 2.21–21.7%, I2: 68%) than in imported cases (p: 0.0004, OR: 2.15, 95% CI: 1.41–3.29%, I2: 63%). P. ovale infections misidentified as P. vivax malaria by the microscopic method were frequent and led to underreported P. ovale cases. The molecular identification of P. ovale malaria in endemic areas is needed because a higher rate of P. ovale misidentification was found in endemic or indigenous cases than in imported cases. In addition, updated courses, enhanced training, and refreshers for microscopic examinations, particularly for P. ovale identification, are necessary to improve the microscopic identification of Plasmodium species in rural health centres where PCR is unavailable.
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spelling doaj.art-2ea7ab225e7247409428c0310c4211af2022-12-21T20:36:17ZengNature PortfolioScientific Reports2045-23222020-12-0110111310.1038/s41598-020-78691-7Misidentification of Plasmodium ovale as Plasmodium vivax malaria by a microscopic method: a meta-analysis of confirmed P. ovale casesManas Kotepui0Frederick Ramirez Masangkay1Kwuntida Uthaisar Kotepui2Giovanni De Jesus Milanez3Medical Technology, School of Allied Health Sciences, Walailak UniversityDepartment of Medical Technology, Institute of Arts and Sciences, Far Eastern University-ManilaMedical Technology, School of Allied Health Sciences, Walailak UniversityDepartment of Medical Technology, Institute of Arts and Sciences, Far Eastern University-ManilaAbstract Plasmodium ovale is a benign tertian malaria parasite that morphologically resembles Plasmodium vivax. P. ovale also shares similar tertian periodicity and can cause relapse in patients without a radical cure, making it easily misidentified as P. vivax in routine diagnosis. Therefore, its prevalence might be underreported worldwide. The present study aimed to quantify the prevalence of P. ovale misidentified as P. vivax malaria using data from studies reporting confirmed P. ovale cases by molecular methods. Studies reporting the misidentification of P. ovale as P. vivax malaria were identified from three databases, MEDLINE, Web of Science, and Scopus, without language restrictions, but the publication date was restricted to 1993 and 2020. The quality of the included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS). The random-effects model was used to estimate the pooled prevalence of the misidentification of P. ovale as P. vivax malaria by the microscopic method when compared to those with the reference polymerase chain reaction method. Subgroup analysis of participants was also performed to demonstrate the difference between imported and indigenous P. ovale cases. The heterogeneity of the included studies was assessed using Cochran's Q and I2 statistics. Publication bias across the included studies was assessed using the funnel plot and Egger’s test, and if required, contour-enhanced funnel plots were used to identify the source(s) of funnel plot asymmetry. Of 641 articles retrieved from databases, 22 articles met the eligibility criteria and were included in the present study. Of the 8,297 malaria-positive cases identified by the PCR method, 453 P. ovale cases were confirmed. The pooled prevalence of misidentification of P. ovale as P. vivax malaria by the microscopic method was 11% (95% CI: 7–14%, I2: 25.46%). Subgroup analysis of the participants demonstrated a higher prevalence of misidentification in indigenous cases (13%, 95% CI: 6–21%, I2: 27.8%) than in imported cases (10%, 95% CI: 6–14%, I2: 24.1%). The pooled prevalence of misidentification of P. vivax as P. ovale malaria by the microscopic method was 1%, without heterogeneity (95% CI: 0–3%, I2: 16.8%). PCR was more sensitive in identifying P. ovale cases than the microscopic method (p < 0.00001, OR: 2.76, 95% CI: 1.83–4.15, I2: 65%). Subgroup analysis of participants demonstrated the better performance of PCR in detecting P. ovale malaria in indigenous cases (p: 0.0009, OR: 6.92, 95% CI: 2.21–21.7%, I2: 68%) than in imported cases (p: 0.0004, OR: 2.15, 95% CI: 1.41–3.29%, I2: 63%). P. ovale infections misidentified as P. vivax malaria by the microscopic method were frequent and led to underreported P. ovale cases. The molecular identification of P. ovale malaria in endemic areas is needed because a higher rate of P. ovale misidentification was found in endemic or indigenous cases than in imported cases. In addition, updated courses, enhanced training, and refreshers for microscopic examinations, particularly for P. ovale identification, are necessary to improve the microscopic identification of Plasmodium species in rural health centres where PCR is unavailable.https://doi.org/10.1038/s41598-020-78691-7
spellingShingle Manas Kotepui
Frederick Ramirez Masangkay
Kwuntida Uthaisar Kotepui
Giovanni De Jesus Milanez
Misidentification of Plasmodium ovale as Plasmodium vivax malaria by a microscopic method: a meta-analysis of confirmed P. ovale cases
Scientific Reports
title Misidentification of Plasmodium ovale as Plasmodium vivax malaria by a microscopic method: a meta-analysis of confirmed P. ovale cases
title_full Misidentification of Plasmodium ovale as Plasmodium vivax malaria by a microscopic method: a meta-analysis of confirmed P. ovale cases
title_fullStr Misidentification of Plasmodium ovale as Plasmodium vivax malaria by a microscopic method: a meta-analysis of confirmed P. ovale cases
title_full_unstemmed Misidentification of Plasmodium ovale as Plasmodium vivax malaria by a microscopic method: a meta-analysis of confirmed P. ovale cases
title_short Misidentification of Plasmodium ovale as Plasmodium vivax malaria by a microscopic method: a meta-analysis of confirmed P. ovale cases
title_sort misidentification of plasmodium ovale as plasmodium vivax malaria by a microscopic method a meta analysis of confirmed p ovale cases
url https://doi.org/10.1038/s41598-020-78691-7
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