Subpatent malaria in a low transmission African setting: a cross-sectional study using rapid diagnostic testing (RDT) and loop-mediated isothermal amplification (LAMP) from Zambezi region, Namibia
Abstract Background Subpatent malaria infections, or low-density infections below the detection threshold of microscopy or standard rapid diagnostic testing (RDT), can perpetuate persistent transmission and, therefore, may be a barrier for countries like Namibia that are pursuing malaria elimination...
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2018-12-01
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Online Access: | http://link.springer.com/article/10.1186/s12936-018-2626-5 |
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record_format |
Article |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Patrick McCreesh Davis Mumbengegwi Kathryn Roberts Munyaradzi Tambo Jennifer Smith Brooke Whittemore Gerard Kelly Caitlin Moe Max Murphy Mukosha Chisenga Bryan Greenhouse Henry Ntuku Immo Kleinschmidt Hugh Sturrock Petrina Uusiku Roland Gosling Adam Bennett Michelle S. Hsiang |
spellingShingle |
Patrick McCreesh Davis Mumbengegwi Kathryn Roberts Munyaradzi Tambo Jennifer Smith Brooke Whittemore Gerard Kelly Caitlin Moe Max Murphy Mukosha Chisenga Bryan Greenhouse Henry Ntuku Immo Kleinschmidt Hugh Sturrock Petrina Uusiku Roland Gosling Adam Bennett Michelle S. Hsiang Subpatent malaria in a low transmission African setting: a cross-sectional study using rapid diagnostic testing (RDT) and loop-mediated isothermal amplification (LAMP) from Zambezi region, Namibia Malaria Journal Malaria Malaria elimination Subpatent Submicroscopic Subclinical Asymptomatic |
author_facet |
Patrick McCreesh Davis Mumbengegwi Kathryn Roberts Munyaradzi Tambo Jennifer Smith Brooke Whittemore Gerard Kelly Caitlin Moe Max Murphy Mukosha Chisenga Bryan Greenhouse Henry Ntuku Immo Kleinschmidt Hugh Sturrock Petrina Uusiku Roland Gosling Adam Bennett Michelle S. Hsiang |
author_sort |
Patrick McCreesh |
title |
Subpatent malaria in a low transmission African setting: a cross-sectional study using rapid diagnostic testing (RDT) and loop-mediated isothermal amplification (LAMP) from Zambezi region, Namibia |
title_short |
Subpatent malaria in a low transmission African setting: a cross-sectional study using rapid diagnostic testing (RDT) and loop-mediated isothermal amplification (LAMP) from Zambezi region, Namibia |
title_full |
Subpatent malaria in a low transmission African setting: a cross-sectional study using rapid diagnostic testing (RDT) and loop-mediated isothermal amplification (LAMP) from Zambezi region, Namibia |
title_fullStr |
Subpatent malaria in a low transmission African setting: a cross-sectional study using rapid diagnostic testing (RDT) and loop-mediated isothermal amplification (LAMP) from Zambezi region, Namibia |
title_full_unstemmed |
Subpatent malaria in a low transmission African setting: a cross-sectional study using rapid diagnostic testing (RDT) and loop-mediated isothermal amplification (LAMP) from Zambezi region, Namibia |
title_sort |
subpatent malaria in a low transmission african setting: a cross-sectional study using rapid diagnostic testing (rdt) and loop-mediated isothermal amplification (lamp) from zambezi region, namibia |
publisher |
BMC |
series |
Malaria Journal |
issn |
1475-2875 |
publishDate |
2018-12-01 |
description |
Abstract Background Subpatent malaria infections, or low-density infections below the detection threshold of microscopy or standard rapid diagnostic testing (RDT), can perpetuate persistent transmission and, therefore, may be a barrier for countries like Namibia that are pursuing malaria elimination. This potential burden in Namibia has not been well characterized. Methods Using a two-stage cluster sampling, cross-sectional design, subjects of all age were enrolled during the end of the 2015 malaria transmission season in Zambezi region, located in northeast Namibia. Malaria RDTs were performed with subsequent gold standard testing by loop-mediated isothermal amplification (LAMP) using dried blood spots. Infection prevalence was measured and the diagnostic accuracy of RDT calculated. Relationships between recent fever, demographics, epidemiological factors, and infection were assessed. Results Prevalence of Plasmodium falciparum malaria infection was low: 0.8% (16/1919) by RDT and 2.2% (43/1919) by LAMP. All but one LAMP-positive infection was RDT-negative. Using LAMP as gold standard, the sensitivity and specificity of RDT were 2.3% and 99.2%, respectively. Compared to LAMP-negative infections, a higher portion LAMP-positive infections were associated with fever (45.2% vs. 30.4%, p = 0.04), though 55% of infections were not associated with fever. Agricultural occupations and cattle herding were significantly associated with LAMP-detectable infection (Adjusted ORs 5.02, 95% CI 1.77–14.23, and 11.82, 95% CI 1.06–131.81, respectively), while gender, travel, bed net use, and indoor residual spray coverage were not. Conclusions This study presents results from the first large-scale malaria cross-sectional survey from Namibia using molecular testing to characterize subpatent infections. Findings suggest that fever history and standard RDTs are not useful to address this burden. Achievement of malaria elimination may require active case detection using more sensitive point-of-care diagnostics or presumptive treatment and targeted to high-risk groups. |
topic |
Malaria Malaria elimination Subpatent Submicroscopic Subclinical Asymptomatic |
url |
http://link.springer.com/article/10.1186/s12936-018-2626-5 |
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doaj-d84ad1edf4b145dcbcea426396cdd36e2020-11-25T01:35:51ZengBMCMalaria Journal1475-28752018-12-0117111110.1186/s12936-018-2626-5Subpatent malaria in a low transmission African setting: a cross-sectional study using rapid diagnostic testing (RDT) and loop-mediated isothermal amplification (LAMP) from Zambezi region, NamibiaPatrick McCreesh0Davis Mumbengegwi1Kathryn Roberts2Munyaradzi Tambo3Jennifer Smith4Brooke Whittemore5Gerard Kelly6Caitlin Moe7Max Murphy8Mukosha Chisenga9Bryan Greenhouse10Henry Ntuku11Immo Kleinschmidt12Hugh Sturrock13Petrina Uusiku14Roland Gosling15Adam Bennett16Michelle S. Hsiang17Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF)Multidisciplinary Research Center, University of NamibiaMalaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF)Multidisciplinary Research Center, University of NamibiaMalaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF)Department of Pediatrics, University of Texas Southwestern Medical CenterBurnet Institute for Medical Research and Public HealthMalaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF)Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, UCSFMultidisciplinary Research Center, University of NamibiaDivision of HIV, Infectious Diseases and Global Medicine, Department of Medicine, UCSFMalaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF)Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical MedicineMalaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF)National Vectorborne Disease Control Programme, Namibia Ministry of Health and Social ServicesMalaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF)Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF)Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF)Abstract Background Subpatent malaria infections, or low-density infections below the detection threshold of microscopy or standard rapid diagnostic testing (RDT), can perpetuate persistent transmission and, therefore, may be a barrier for countries like Namibia that are pursuing malaria elimination. This potential burden in Namibia has not been well characterized. Methods Using a two-stage cluster sampling, cross-sectional design, subjects of all age were enrolled during the end of the 2015 malaria transmission season in Zambezi region, located in northeast Namibia. Malaria RDTs were performed with subsequent gold standard testing by loop-mediated isothermal amplification (LAMP) using dried blood spots. Infection prevalence was measured and the diagnostic accuracy of RDT calculated. Relationships between recent fever, demographics, epidemiological factors, and infection were assessed. Results Prevalence of Plasmodium falciparum malaria infection was low: 0.8% (16/1919) by RDT and 2.2% (43/1919) by LAMP. All but one LAMP-positive infection was RDT-negative. Using LAMP as gold standard, the sensitivity and specificity of RDT were 2.3% and 99.2%, respectively. Compared to LAMP-negative infections, a higher portion LAMP-positive infections were associated with fever (45.2% vs. 30.4%, p = 0.04), though 55% of infections were not associated with fever. Agricultural occupations and cattle herding were significantly associated with LAMP-detectable infection (Adjusted ORs 5.02, 95% CI 1.77–14.23, and 11.82, 95% CI 1.06–131.81, respectively), while gender, travel, bed net use, and indoor residual spray coverage were not. Conclusions This study presents results from the first large-scale malaria cross-sectional survey from Namibia using molecular testing to characterize subpatent infections. Findings suggest that fever history and standard RDTs are not useful to address this burden. Achievement of malaria elimination may require active case detection using more sensitive point-of-care diagnostics or presumptive treatment and targeted to high-risk groups.http://link.springer.com/article/10.1186/s12936-018-2626-5MalariaMalaria eliminationSubpatentSubmicroscopicSubclinicalAsymptomatic |