CoChat
Sign Up
Cited by 25Malaria Research and ControlHemoglobinopathies and Related DisordersGlobal Maternal and Child Health

What is the burden of submicroscopic malaria in pregnancy in central India?

Open access
Singh, Neeru, Bharti, Praveen K., Singh, Mrigendra P., Singh, Rajshree, Yeboah-Antwi, Kojo, Desai, Meghna, Udhayakumar, Venkatachalam, Muniyandi, Malaisamy +2 more·2015·Pathogens and Global Health
DOI 10.1179/2047773215y.0000000002PMC PMC4445293
Open this paper in CoChat — free account

Abstract

BACKGROUND: Conventional microscopy underestimates the burden of malarial infection when compared with molecular diagnosis using polymerase chain reaction (PCR)-based methods. Lower density parasitemias serve as a reservoir for infection. We evaluated the prevalence of submicroscopic infections in an area of unstable malarial transmission in India and determined whether these infections negatively impacted maternal or fetal outcomes. METHODS: This cross-sectional study (2007-2008) was undertaken in two districts of Chhattisgarh, recruiting women from both antenatal clinics (ANCs) and delivery units (DUs). For ANC/DU subjects, peripheral/placental blood, respectively, was obtained for conventional microscopy and collected onto filter paper for PCR analysis. RESULTS: There were 3425 pregnant women, including 2477 ANC subjects and 948 DU subjects who had both microscopic and PCR samples available. Polymerase chain reaction detected significantly more Plasmodium infections than traditional light microscopy both from peripheral (3·4 vs 1·2%; OR 2·9, 95% confidence intervals (CIs) 1·9-4·5) and placental (4·2 vs 1·7%; OR 2·5, 95% CIs 1·4-4·8) blood samples. Submicroscopic infections were not associated with anemia or severe maternal anemia among ANC or DU participants and were not associated with low birth weight (LBW) among DU participants. In contrast, microscopically detected infections were associated with severe anemia and LBW. CONCLUSIONS: In this area of unstable malarial transmission from India, submicroscopic infections did not identify a set of pregnant women at increased risk for anemia or LBW. Until PCR techniques become much less expensive and available as a point of care test for the field setting, its use will be limited for malarial detection.

AI snapshot

Written from the paper’s full text.

TL;DR

In this cross-sectional study in Chhattisgarh, India, PCR detected more Plasmodium infections than microscopy in pregnant women, and about two-thirds of peripheral and placental infections were submicroscopic. Submicroscopic infections were not associated with anemia or low birth weight, whereas microscopically detected infections were.

Key findings

Among 3425 pregnant women with both microscopy and PCR results (2477 antenatal clinic [ANC] and 948 delivery unit [DU] subjects), PCR detected more infections than microscopy: peripheral blood 3.4% vs 1.2% (OR 2.9, 95% CI 1.9–4.5) and placental blood 4.2% vs 1.7% (OR 2.5, 95% CI 1.4–4.8).

  • Submicroscopic infections accounted for 59/89 peripheral infections (66.3%, 95% CI 55.9–75.3) and 29/45 placental infections (64.4%, 95% CI 49.8–76.8). Peripheral P. vivax infections were more often submicroscopic than P. falciparum infections (38/42, 90.5% vs 26/52, 50.0%; P<0.001); placental samples showed no significant species difference (64.7% vs 66.7%, P=0.90).
  • Submicroscopic infections were not associated with anemia or severe anemia among ANC or DU participants and were not associated with low birth weight (LBW) among DU participants. In contrast, microscopically detected infections were associated with severe anemia (peripheral: 30.0% vs 3.0%; OR 13.7, 95% CI 5.3–32.5) and LBW (placental: 75.0% vs 34.0%; OR 5.8, 95% CI 1.4–33.7).
  • All PCR-detected infections combined (microscopic plus submicroscopic) were associated with severe anemia (OR 3.7, 95% CI 1.6–7.8), but with a smaller effect size than microscopy alone; PCR-detected infections were not associated with LBW.

Methods

Cross-sectional study conducted June 2007–May 2008 in Rajnandgaon and Bastar districts, Chhattisgarh, central India; pregnant women aged ≥15 years were recruited from ANCs and DUs as two distinct cohorts and were not followed longitudinally.

  • Peripheral blood was collected from ANC subjects; peripheral and placental blood were collected from DU subjects. Samples underwent Giemsa microscopy and filter-paper PCR using species-specific nested PCR targeting the 18s rRNA gene; hemoglobin, birth weight, and Ballard gestational age were also assessed.
  • Analysis used Stata/IC 8.2 with percentages and 95% CIs, chi-square or Fisher’s exact tests, odds ratios, univariate logistic regression, and ANOVA; adjusted analyses were not performed.

Limitations

The paper states that this was a cross-sectional facility-based study rather than a prospective longitudinal study; there were no matched peripheral and placental samples; microscopy was limited to 100 fields per WHO standards; low parasitemia prevalence and rare outcomes limited power; almost one quarter of DU infections were P. vivax, which is less strongly linked with adverse pregnancy outcomes; and placental histology was not collected.

  • The paper also notes that PCR was performed only on peripheral blood from ANC subjects and placental blood from DU participants, so peripheral and placental PCR could not be compared within the same women. PCR missed 10 microscopy-positive infections (5 peripheral, 5 placental), possibly because filter-paper samples had little blood and failed to amplify.
  • Evident from the text: adjusted analyses were not performed, so the reported associations are unadjusted.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1179/2047773215y.0000000002

Cites

32 of 32 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 39 cited sources checked · 0 supported · 0 flagged

  • Findingown data
    § Prevalence of microscopic and submicroscopic parasitemia

    Women who did not sleep under a bednet on most nights had a higher likelihood of microscopically detected peripheral infection (P=0.014).

    “Peripheral and placental infections among women who did not sleep under a bednet on most nights were more likely to have a microscopic infection, although reaching significance only for the peripheral infections ( P 5 0.014).”
    Quote in the paperNot a substantial claim
  • Findingown data
    § Prevalence of microscopic and submicroscopic parasitemia

    PCR detected significantly more Plasmodium infections than traditional light microscopy from placental blood samples (4.2% vs 1.7%; OR 2.5, 95% CI 1.4-4.8).

    “Similarly, the odds of detecting parasitemia by PCR were over two-fold higher than microscopy for placental samples (4.2 vs 1.7%, OR 2.5; 95% CIs 1.4-4.8).”
    Quote in the paperSubstantial claim
  • Findingown data
    § Conclusion

    PCR does not appear to identify a group of women at risk for adverse maternal or infant outcome.

    “do not appear to identify a group of women at risk for adverse maternal or infant outcome”
    Quote in the paperSubstantial claim
  • Findingown data
    § Birth outcomes

    Having a malarial infection detected by either microscopy or PCR did not significantly increase the odds for stillbirth.

    “Having a malarial infection detected by either microscopy or PCR did not significantly increase the odds for stillbirth”
    Quote in the paperSubstantial claim
  • Findingown data
    § Birth outcomes

    Women with microscopically detected placental infections were more likely to deliver a low birth weight infant (OR 5.8, 95% CI 1.4-33.7) compared to women with negative smears.

    “Women with microscopically detected placental infections were more likely to deliver a LBW infant (OR 5.8, 95% CIs 1.4-33.7) compared to women with negative smears.”
    Quote in the paperSubstantial claim
  • May combine two claims. 19
  • The quote only partly states this claim. 1
  • Classified as probably not a substantial claim. 27

  • May combine two claims.

    Findingown data
    § Discussion

    The majority of malarial infections in pregnant women in this study were submicroscopic: 66.3% of peripheral infections and 64.4% of placental infections.

    “Indeed, the majority of infections was submicroscopic (66.3% of peripheral and 64.4% of placental infections)”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Prevalence of microscopic and submicroscopic parasitemia

    Women who did not sleep under a bednet on most nights had a higher likelihood of microscopically detected placental infection, but this was not statistically significant.

    “Peripheral and placental infections among women who did not sleep under a bednet on most nights were more likely to have a microscopic infection, although reaching significance only for the peripheral infections ( P 5 0.014).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data
    § Prevalence of microscopic and submicroscopic parasitemia

    In ANC samples, the proportion of submicroscopic infections was over 90% for P. vivax (38/42; 90.5%) compared to 50.0% for P. falciparum (26/52; P<0.001 comparing species).

    “In ANC samples, the proportion of submicroscopic infections was over 90% for P. vivax (38/42; 90.5%) compared to only half of the P. falciparum infections (26/52; 50.0%; P , 0.001 comparing species).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning
    § Discussion

    When evaluating all PCR-detected infections including both microscopic and submicroscopic infections, parasitemia was associated with severe maternal anemia and low birth weight, but the effect size was diminished compared with microscopic infections considered alone.

    “When evaluating all PCR-detected infections including both microscopic and submicroscopic infections, parasitemia was associated with severe maternal anemia and LBW but the effect size was diminished compared with microscopic infections considered alone.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Birth outcomes

    The prevalence of low birth weight among women with positive PCR samples (36.4%) was similar to those with negative PCR samples (34.9%) and with negative microscopy (34.0%) and much lower than women with positive microscopy (75.0%).

    “Notably, the prevalence of LBW among women with positive PCR samples (36.4%) was similar to those with negative PCR samples (34.9%) and with negative microscopy (34.0%) and much lower than women with positive microscopy (75.0%).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Anemia

    Neither positive microscopy nor positive PCR from placental samples was associated with a lesser degree of anemia (Hgb < 11 g/dl).

    “Neither positive microscopy nor positive PCR from placental samples was associated with a lesser degree of anemia (Hgb , 11 g/dl).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Discussion

    Microscopically detected infections were associated with both severe anemia and low birth weight.

    “This differs from the microscopically detected infections, which were associated with both severe anemia and LBW.”
    Quote in the paperSubstantial claim

  • The quote only partly states this claim.

    Findingown data
    § Anemia

    In pregnant women in central India, PCR detected a higher prevalence of peripheral malaria parasitemia than light microscopy (84/2477, 3.4% vs 30/2477, 1.2%; OR 2.9, 95% CI 1.9-4.5).

    “PCR | 45 (1.8) | 1.7 (1.0-2.8) | 40 (1.6) | 8.1 (3.2-26.3) | 84 b (3.4) | 2.9 (1.9-4.5)”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Discussion

    Submicroscopic malarial infections in pregnant women in this study were not associated with maternal anemia of any degree or with low birth weight.

    “we did not identify an association between submicroscopic infections and either maternal anemia of any degree or LBW.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation
    § Introduction

    Data are conflicting about the impact of submicroscopic infections on LBW; some studies suggest increased risk and others no association.

    “Similarly, the data are conflicting about the impact of submicroscopic infections on LBW; some studies suggest an increased risk 16,24 in the setting of submicroscopic infections and others no association. 20-23”
    Quote in the paperSubstantial claim0 of 6 sources checked
    • cites [16] Adegnika AA, 2006, Am J Trop Med Hyg. source

      Not checked in the free run.

    • cites [24] Mohammed AH, 2013, Malar J. source

      Not checked in the free run.

    • cites [20] Mayor A, 2012, Clin Infect Dis. source

      Not checked in the free run.

    • cites [21] Cohee LM, 2014, Malar J. source

      Not checked in the free run.

    • cites [22] Rantala AM, 2010, Malar J. source

      Not checked in the free run.

    • cites [23] Mockenhaupt FP, 2006, Malar J. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § Introduction

    Submicroscopic infections were linked with maternal anemia in some studies but not all.

    “Submicroscopic infections were linked with maternal anemia in some 17,18,20,23 but not all 12,13,15,21 studies.”
    Quote in the paperNot a substantial claim0 of 8 sources checked
    • cites [17] Mayor A, 2009, Malar J. source

      Not checked in the free run.

    • cites [18] Mockenhaupt FP, 2002, J Clinical Microbiol. source

      Not checked in the free run.

    • cites [20] Mayor A, 2012, Clin Infect Dis. source

      Not checked in the free run.

    • cites [23] Mockenhaupt FP, 2006, Malar J. source

      Not checked in the free run.

    • cites [12] Mockenhaupt FP, 2000, Trop Med Int Health. source

      Not checked in the free run.

    • cites [13] Saute F, 2002, Trop Med Int Health. source

      Not checked in the free run.

    • cites [15] Walker-Abbey A, 2005, Am J Trop Med Hyg. source

      Not checked in the free run.

    • cites [21] Cohee LM, 2014, Malar J. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Introduction

    In one study from Northwest Colombia, 79% of all infections at delivery were submicroscopic.

    “In one study from Northwest Colombia where both P. falciparum and Plasmodium vivax are present, 79% of all infections at the time of delivery were submicroscopic. 25”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [25] Arango EM, 2013, Am J Trop Med Hyg. source

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation
    § Introduction

    Low-density parasitemias serve as a reservoir for continued transmission of malaria and may contribute to negative health.

    “These low-density parasitemias serve as a reservoir for continued transmission of the disease and may contribute to negative health. 9-11”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [9] Giha HA, 2005, Microbes Infect. source

      Not checked in the free run.

    • cites [10] Mosha JF, 2013, Malar J. source

      Not checked in the free run.

    • cites [11] Mens P, 2007, Trop Med Int Health. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Introduction

    In that Northwest Colombia study, submicroscopic infections were associated with placental villitis and intervillitis.

    “Notably, these submicroscopic infections were associated with placental villitis and intervillitis, inflammatory lesions in the placenta that may contribute to poor birth outcomes.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [25] Arango EM, 2013, Am J Trop Med Hyg. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Introduction

    A seasoned microscopist can discern parasitemias only above approximately 100 parasites per microliter, whereas PCR can detect 1 parasite per microliter or less.

    “A seasoned microscopist is only able to discern parasitemias above a density of approximately 100 parasites per microliter 6,7 compared with PCR where detection can occur at 1 parasite per microliter or less. 8”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [6] World Health Organization, 1988, Bull World Health Organ.

      Not checked in the free run.

    • cites [7] Dowling MA, 1966, Bull World Health Organ.

      Not checked in the free run.

    • cites [8] Kamau E, 2013, PLoS One source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Introduction

    Between low and high transmission extremes, there is an inverse relationship between the proportion of submicroscopic infections and transmission intensity (by PCR prevalence).

    “Between these two extremes, there was an inverse relationship between the proportion of submicroscopic infections and the transmission intensity (by PCR prevalence).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [5] Okell LC, 2009, J Infect Dis. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Introduction

    The proportion of malarial infections that are submicroscopic is higher in areas of low transmission; a meta-analysis reported 88% undetected by microscopy in low-transmission areas compared to 25.5% in high-transmission areas.

    “A meta-analysis of surveys conducted in endemic areas reported that 88% of all infections went undetected by microscopy in areas of low transmission compared to only 25.5% in areas of high transmission. 5”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [5] Okell LC, 2009, J Infect Dis. source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductnone given
    § Discussion

    The study was cross-sectional facility based rather than prospective longitudinal.

    “First, this was a cross-sectional facility based study rather than a prospective longitudinal study.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given
    § Discussion

    Tissue sections were not collected for histology in the study.

    “However, tissue sections were not collected for histology in our study.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given
    § Data management and analysis

    Adjusted analyses were not performed.

    “Adjusted analyses were not performed.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation
    § Discussion

    Microscopic readings for initial detection of parasitemia were limited to 100 microscopic fields as per WHO standards.

    “Microscopic readings for initial detection of parasitemia were limited to 100 microscopic fields as per World Health Organization standards for microscopic diagnosis of malaria. 31”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [31] World Health Organization. Parasitological confirmation of malaria diagnosis; 2009. Available from: http://whqlibdoc.who.int/publications/2010/9789241599412_eng.pdf (accessed 2013 August 16).

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Discussion

    The DNA detected by PCR may be from a viable asexual parasite, a gametocyte, or represent nonviable DNA from past infections following treatment.

    “The DNA detected by PCR may be from a viable asexual parasite, a gametocyte, or represent nonviable DNA from past infections following treatment. 35”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [35] Kain KC, 1994, J Infect Dis. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § Discussion

    Microscopy visualizes viable whole parasites in erythrocytes, while PCR detects parasite DNA.

    “Microscopy visualizes viable whole parasites in erythrocytes, while PCR detects parasite DNA. 34”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [34] Singer LM, 2004, Am J Trop Med Hyg. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning
    § Discussion

    PCR techniques are unlikely to identify past infections that occurred remote from delivery given the clearance of nonviable DNA.

    “Furthermore, PCR techniques are unlikely to identify past infections that occurred remote from delivery given the clearance of nonviable DNA.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given
    § Laboratory procedures

    An experienced microscopist blinded to PCR results and clinical history examined the blood films.

    “An experienced microscopist who was blinded to the PCR results and clinical history of the subject examined the blood films.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning
    § Discussion

    The detection of recent past infections may account for why the submicroscopic infections are not associated with concurrent anemia or severe anemia in the subjects.

    “This detection of recent past infections may account for why the submicroscopic infections are not associated with concurrent anemia or severe anemia in our subjects”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning
    § Laboratory procedures

    Because of limited resources, PCR was performed only on peripheral blood samples from ANC subjects and placental blood samples from DU participants.

    “Because of limited resources, we performed only PCR on peripheral blood samples from ANC subjects and placental blood samples from DU participants.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning
    § Discussion

    More likely, submicroscopic infections reflect lower density parasitemias, which may not be as strongly linked with anemia in a population with a fairly high degree of anemia at baseline.

    “More likely, submicroscopic infections reflect lower density parasitemias, which may not be as strongly linked with anemia in a population with a fairly high degree of anemia at baseline.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given
    § Data management and analysis

    Results of PCR and microscopy were recorded on separate forms; after double data entry, the database was rechecked for inconsistent entries and errors corrected.

    “Results of the PCR and microscopy examination were recorded on separate forms. After double data entry, the database was rechecked for inconsistent entries and errors were corrected.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data
    § Results

    Peripheral dried blood spots for PCR were available for comparison with peripheral microscopy for 2477 of 2696 women recruited from ANC.

    “Peripheral dried blood spots for PCR were available for comparison with peripheral microscopy for 2477 of the 2696 women recruited from the ANC.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given
    § Laboratory procedures

    All smears were rechecked by a member of the parasitology laboratory at NIMR Field Station in Jabalpur.

    “All smears were rechecked by a member of the parasitology laboratory at the National Institute of Malaria Research (NIMR) Field Station in Jabalpur.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationown data
    § Prevalence of microscopic and submicroscopic parasitemia

    The DNA extracted from filter paper samples that PCR missed had little blood and failed to amplify, which may have contributed to the observed results.

    “The DNA extracted from these filter paper samples had little blood in them and failed to amplify; this may have contributed to the observed results.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductnone given
    § Species-specific nested PCR

    An independent research assistant unaware of participant's clinical status or microscopy results performed PCR on coded samples.

    “An independent research assistant unaware of the participant's clinical status or the microscopy results performed the PCR on coded samples.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data
    § Results

    Placental dried blood spots for PCR were available for comparison with placental blood microscopy/impression smears in 948 of 1030 women recruited from DUs.

    “Placental dried blood spots for PCR were available for comparison with placental blood microscopy/impression smears in 948 of the 1030 women recruited from DUs.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning
    § Discussion

    The sensitivity of microscopy for detecting parasitemia might have been slightly higher if 200 or more fields had been read in the thick blood films for initial identification of positive specimens.

    “The sensitivity of microscopy for detecting parasitemia might have been slightly higher if 200 or more fields had been read in the thick blood films for initial identification of positive specimens.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given
    § Laboratory procedures

    A portable Hemocue machine was used for hemoglobin estimation with the manufacturers' internal quality control before each assay.

    “A portable Hemocue machine (A ¨ ngelholm, Sweden) was used for hemoglobin estimation using the manufacturers' internal quality control before each assay.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given
    § Discussion

    The use of malaria prevention measures may have been less in more impoverished women.

    “The use of these measures may have been less in more impoverished women;”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data
    § Species-specific nested PCR

    All negative slides that tested PCR positive and all positive slides that were PCR negative were reexamined by another expert technician blinded to microscopy, PCR, and clinical status.

    “All negative slides that tested PCR positive and all positive slides that were PCR negative were reexamined by another expert technician blinded to the results of microscopy, PCR, and clinical status of the participants.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductnone given
    § Discussion

    Recruitment of an unselected population of pregnant women receiving antenatal care or at the time of delivery rather than women with symptoms of malaria was a strength of the study.

    “Recruitment of an unselected population of pregnant women receiving antenatal care or at the time of delivery rather than women with symptoms of malaria was a strength of this study.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data
    § Data management and analysis

    Peripheral blood smear results from DU participants were not considered in this analysis because no PCR results were available for comparison.

    “Peripheral blood smear results from DU participants were not considered in this analysis, as no PCR results were available for comparison.”
    Quote in the paperNot a substantial claim
40 of 40

  • The paper relies on this without support.

    Limited information on the epidemiology of submicroscopic malarial infections during pregnancy is available from areas outside Africa where levels of malarial transmission are much lower.

    “Limited information on the epidemiology of submicroscopic malarial infections during pregnancy is available from areas outside of Africa where levels of malarial transmission are much lower.”

  • The paper relies on this without support.

    The clinical relevance of submicroscopic malarial infections in pregnancy has not been evaluated from the Asia-Pacific region.

    “The clinical relevance of submicroscopic malarial infections in pregnancy has not been evaluated from the Asia-Pacific region where malaria prevalence is much lower than sub-Saharan Africa. 26”

  • The paper relies on this without support.

    PCR techniques are expensive and labor intensive, require sophisticated equipment and personnel.

    “since PCR techniques are expensive and labor intensive, require sophisticated equipment and personnel”

  • The paper relies on this without support.

    P. vivax infections are less strongly linked with adverse pregnancy outcomes than P. falciparum.

    “which are less strongly linked with adverse pregnancy outcomes”
4 of 4

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Cites

Flagged first, then by citations

Research works printed but not linked: 4

  1. Singh N, 1999, Bull World Health Organ., 77, 567
  2. World Health Organization, 1988, Bull World Health Organ., 66, 575
  3. Dowling MA, 1966, Bull World Health Organ., 34, 249
  4. Anon, 2008–10, State vector borne disease control programme: malaria control programme annual report: 2000–2010, state vector borne disease control programme in Raipur Chhattisgarh

Cited by

Sorted by citations

Related

Authors
Singh, N., Bharti, P. K., Singh, M. P., Singh, R., Yeboah-Antwi, K., Desai, M., Udhayakumar, V., Muniyandi, M., Hamer, D. H., & Wylie, B. J.
Affiliations
  • National Institute for Research in Tribal Health (IN)
  • National Institute of Malaria Research (IN)
  • Centers for Disease Control and Prevention (US)
  • Boston University (US)
  • Harvard University (US)
Corresponding author
Singh, Neeru
ORCID
Venue
Pathogens and Global Health
Publisher
Informa UK Limited
Published
2015-01-28
Volume
109
Issue
1
Pages
30-38
ISSN
  • 2047-7724 (ISSN-L)
  • 2047-7732
DOI
10.1179/2047773215y.0000000002
PMC
PMC4445293
OpenAlex
W1994840465
Semantic Scholar
18721770590924add8088eb3115821db403d5390
Cited by
25
References
32
Citations by year
2026: 1 · 2025: 2 · 2024: 2 · 2023: 5 · 2022: 4 · 2019: 3 · 2018: 3 · 2017: 3 · 2016: 1 · 2015: 1
FWCI
2.86
Type
journal article
Language
en
Open access
Locations
  • Pathogens and Global Health (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • Indian Council of Medical Research
  • National Institutes of Health
  • National Institute of Environmental Health Sciences (K23ES021471)
  • Eunice Kennedy Shriver National Institute of Child Health and Human Development (R03HD052167, 1 R03 HD52167-01)
Topics
  • Health Sciences › Medicine › Public Health, Environmental and Occupational Health › Malaria Research and Control
  • Health Sciences › Medicine › Genetics › Hemoglobinopathies and Related Disorders
  • Health Sciences › Medicine › Pediatrics, Perinatology and Child Health › Global Maternal and Child Health
Keywords
submicroscopic malaria infection, malaria in pregnancy, Plasmodium, PCR diagnosis, conventional microscopy, placental malaria, anemia in pregnancy, low birth weight, unstable malaria transmission, Chhattisgarh, prenatal care
MeSH terms
Adolescent, Adult, Blood, Cross-Sectional Studies, Female, Humans, India, Infant, Newborn, Malaria, Microscopy, Pregnancy, Pregnancy Complications, Infectious, Prevalence, Polymerase Chain Reaction, Parasitemia, Young Adult

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-10.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-10.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review