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High proportions of asymptomatic and submicroscopic Plasmodium vivax infections in a peri-urban area of low transmission in the Brazilian Amazon

BACKGROUND: Population-based studies conducted in Latin America have shown a high proportion of asymptomatic and submicroscopic malarial infections. Considering efforts aiming at regional elimination, it is important to investigate the role of this asymptomatic reservoir in malaria transmission in p...

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Autores principales: Almeida, Anne C. G., Kuehn, Andrea, Castro, Arthur J. M., Vitor-Silva, Sheila, Figueiredo, Erick F. G., Brasil, Larissa W., Brito, Marcelo A. M., Sampaio, Vanderson S., Bassat, Quique, Felger, Ingrid, Tadei, Wanderli P., Monteiro, Wuelton M., Mueller, Ivo, Lacerda, Marcus V. G.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5859403/
https://www.ncbi.nlm.nih.gov/pubmed/29558985
http://dx.doi.org/10.1186/s13071-018-2787-7
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author Almeida, Anne C. G.
Kuehn, Andrea
Castro, Arthur J. M.
Vitor-Silva, Sheila
Figueiredo, Erick F. G.
Brasil, Larissa W.
Brito, Marcelo A. M.
Sampaio, Vanderson S.
Bassat, Quique
Felger, Ingrid
Tadei, Wanderli P.
Monteiro, Wuelton M.
Mueller, Ivo
Lacerda, Marcus V. G.
author_facet Almeida, Anne C. G.
Kuehn, Andrea
Castro, Arthur J. M.
Vitor-Silva, Sheila
Figueiredo, Erick F. G.
Brasil, Larissa W.
Brito, Marcelo A. M.
Sampaio, Vanderson S.
Bassat, Quique
Felger, Ingrid
Tadei, Wanderli P.
Monteiro, Wuelton M.
Mueller, Ivo
Lacerda, Marcus V. G.
author_sort Almeida, Anne C. G.
collection PubMed
description BACKGROUND: Population-based studies conducted in Latin America have shown a high proportion of asymptomatic and submicroscopic malarial infections. Considering efforts aiming at regional elimination, it is important to investigate the role of this asymptomatic reservoir in malaria transmission in peri-urban areas. This study aimed to estimate the prevalence of Plasmodium spp. and gametocyte burden on symptomatic and asymptomatic infections in the Brazilian Amazon. RESULTS: Two cross-sectional household surveys (CS) were conducted including all inhabitants in a peri-urban area of Manaus, western Amazonas State, Brazil. Malaria parasites were detected by light microscopy (LM) and qPCR. Sexual stages of Plasmodium spp. were detected by LM and RT-qPCR. A total of 4083 participants were enrolled during the two surveys. In CS1, the prevalence of Plasmodium vivax infections was 4.3% (86/2010) by qPCR and 1.6% (32/2010) by LM. Fifty percent (43/86) of P. vivax infected individuals (qPCR) carried P. vivax gametocytes. In CS2, 3.4% (70/2073) of participants had qPCR-detectable P. vivax infections, of which 42.9% (30/70) of infections were gametocyte positive. The P. vivax parasite density was associated with gametocyte carriage (P < 0.001). Sixty-seven percent of P. vivax infected individuals and 53.4% of P. vivax gametocyte carriers were asymptomatic. CONCLUSIONS: This study confirms a substantial proportion of asymptomatic and submicroscopic P. vivax infections in the study area. Most asymptomatic individuals carried gametocytes and presented low asexual parasitemia. This reservoir actively contributes to malaria transmission in the Brazilian Amazon, underscoring a need to implement more efficient control and elimination strategies. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13071-018-2787-7) contains supplementary material, which is available to authorized users.
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spelling pubmed-58594032018-03-20 High proportions of asymptomatic and submicroscopic Plasmodium vivax infections in a peri-urban area of low transmission in the Brazilian Amazon Almeida, Anne C. G. Kuehn, Andrea Castro, Arthur J. M. Vitor-Silva, Sheila Figueiredo, Erick F. G. Brasil, Larissa W. Brito, Marcelo A. M. Sampaio, Vanderson S. Bassat, Quique Felger, Ingrid Tadei, Wanderli P. Monteiro, Wuelton M. Mueller, Ivo Lacerda, Marcus V. G. Parasit Vectors Research BACKGROUND: Population-based studies conducted in Latin America have shown a high proportion of asymptomatic and submicroscopic malarial infections. Considering efforts aiming at regional elimination, it is important to investigate the role of this asymptomatic reservoir in malaria transmission in peri-urban areas. This study aimed to estimate the prevalence of Plasmodium spp. and gametocyte burden on symptomatic and asymptomatic infections in the Brazilian Amazon. RESULTS: Two cross-sectional household surveys (CS) were conducted including all inhabitants in a peri-urban area of Manaus, western Amazonas State, Brazil. Malaria parasites were detected by light microscopy (LM) and qPCR. Sexual stages of Plasmodium spp. were detected by LM and RT-qPCR. A total of 4083 participants were enrolled during the two surveys. In CS1, the prevalence of Plasmodium vivax infections was 4.3% (86/2010) by qPCR and 1.6% (32/2010) by LM. Fifty percent (43/86) of P. vivax infected individuals (qPCR) carried P. vivax gametocytes. In CS2, 3.4% (70/2073) of participants had qPCR-detectable P. vivax infections, of which 42.9% (30/70) of infections were gametocyte positive. The P. vivax parasite density was associated with gametocyte carriage (P < 0.001). Sixty-seven percent of P. vivax infected individuals and 53.4% of P. vivax gametocyte carriers were asymptomatic. CONCLUSIONS: This study confirms a substantial proportion of asymptomatic and submicroscopic P. vivax infections in the study area. Most asymptomatic individuals carried gametocytes and presented low asexual parasitemia. This reservoir actively contributes to malaria transmission in the Brazilian Amazon, underscoring a need to implement more efficient control and elimination strategies. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13071-018-2787-7) contains supplementary material, which is available to authorized users. BioMed Central 2018-03-20 /pmc/articles/PMC5859403/ /pubmed/29558985 http://dx.doi.org/10.1186/s13071-018-2787-7 Text en © The Author(s). 2018 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research
Almeida, Anne C. G.
Kuehn, Andrea
Castro, Arthur J. M.
Vitor-Silva, Sheila
Figueiredo, Erick F. G.
Brasil, Larissa W.
Brito, Marcelo A. M.
Sampaio, Vanderson S.
Bassat, Quique
Felger, Ingrid
Tadei, Wanderli P.
Monteiro, Wuelton M.
Mueller, Ivo
Lacerda, Marcus V. G.
High proportions of asymptomatic and submicroscopic Plasmodium vivax infections in a peri-urban area of low transmission in the Brazilian Amazon
title High proportions of asymptomatic and submicroscopic Plasmodium vivax infections in a peri-urban area of low transmission in the Brazilian Amazon
title_full High proportions of asymptomatic and submicroscopic Plasmodium vivax infections in a peri-urban area of low transmission in the Brazilian Amazon
title_fullStr High proportions of asymptomatic and submicroscopic Plasmodium vivax infections in a peri-urban area of low transmission in the Brazilian Amazon
title_full_unstemmed High proportions of asymptomatic and submicroscopic Plasmodium vivax infections in a peri-urban area of low transmission in the Brazilian Amazon
title_short High proportions of asymptomatic and submicroscopic Plasmodium vivax infections in a peri-urban area of low transmission in the Brazilian Amazon
title_sort high proportions of asymptomatic and submicroscopic plasmodium vivax infections in a peri-urban area of low transmission in the brazilian amazon
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5859403/
https://www.ncbi.nlm.nih.gov/pubmed/29558985
http://dx.doi.org/10.1186/s13071-018-2787-7
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