Title:
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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
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Author:
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Almeida, Anne Cristine Gomes; Kuehn, Andrea; Castro, Arthur J. M.; Vitor Silva, Sheila; Figueiredo, Erick F. G.; Brasil, Larissa Wanderley; Brito, Marcelo A. M.; Sampaio, Vanderson Souza; Bassat Orellana, Quique; Felger, Ingrid; Tadei, Wanderli P.; Monteiro, Wuelton Marcelo; Mueller, Ivo; Lacerda, Marcus Vinícius Guimarães
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Abstract:
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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. |
Subject(s):
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-Plasmodium vivax -Malalties infeccioses -Plasmodium vivax -Communicable diseases |
Rights:
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cc by (c) Almeida et al., 2018
http://creativecommons.org/licenses/by/3.0/es/ |
Document type:
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Article Article - Published version |
Published by:
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BioMed Central
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