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Malaria elimination challenges in Mesoamerica: evidence of submicroscopic malaria reservoirs in Guatemala

BACKGROUND: Even though malaria incidence has decreased substantially in Guatemala since 2000, Guatemala remains one of the countries with the highest malaria transmission in Mesoamerica. Guatemala is committed to eliminating malaria as part of the initiative ‘Elimination of Malaria in Mesoamerica a...

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Autores principales: Lennon, Shirley Evelyn, Miranda, Adolfo, Henao, Juliana, Vallejo, Andres F., Perez, Julianh, Alvarez, Alvaro, Arévalo-Herrera, Myriam, Herrera, Sócrates
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5006524/
https://www.ncbi.nlm.nih.gov/pubmed/27577992
http://dx.doi.org/10.1186/s12936-016-1500-6
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author Lennon, Shirley Evelyn
Miranda, Adolfo
Henao, Juliana
Vallejo, Andres F.
Perez, Julianh
Alvarez, Alvaro
Arévalo-Herrera, Myriam
Herrera, Sócrates
author_facet Lennon, Shirley Evelyn
Miranda, Adolfo
Henao, Juliana
Vallejo, Andres F.
Perez, Julianh
Alvarez, Alvaro
Arévalo-Herrera, Myriam
Herrera, Sócrates
author_sort Lennon, Shirley Evelyn
collection PubMed
description BACKGROUND: Even though malaria incidence has decreased substantially in Guatemala since 2000, Guatemala remains one of the countries with the highest malaria transmission in Mesoamerica. Guatemala is committed to eliminating malaria as part of the initiative ‘Elimination of Malaria in Mesoamerica and the Island of Hispaniola’ (EMMIE); however, it is still in the control phase. During the past decade, the government strengthened malaria control activities including mass distribution of long-lasting insecticide-impregnated bed nets, early diagnosis and prompt treatment. This study aimed to determine the prevalence of malaria, including gametocytes, in three areas of Guatemala using active case detection (ACD) and quantitative polymerase chain reaction (qPCR). METHODS: Cross-sectional surveys were conducted in three departments with varying transmission intensities: Escuintla, Alta Verapaz and Zacapa. Blood samples from 706 volunteers were screened for malaria using microscopy and qPCR which was also used to determine the prevalence of gametocytes among infected individuals. Results were collected and analysed using REDCap and R Project, respectively. RESULTS: Malaria was diagnosed by microscopy in only 2.8 % (4/141) of the volunteers from Escuintla. By contrast, qPCR detected a prevalence of 7.1 % (10/141) in the same volunteers, 8.4 % (36/429) in Alta Verapaz, and 5.9 % (8/136) in Zacapa. Overall, 7.6 % (54/706) of the screened individuals were positive, with an average parasitaemia level of 40.2 parasites/μL (range 1–1133 parasites/μL) and 27.8 % carried mature gametocytes. Fifty-seven percent (31/54) of qPCR positive volunteers were asymptomatic and out of the 42.6 % of symptomatic individuals, only one had a positive microscopy result. CONCLUSIONS: This study found a considerable number of asymptomatic P. vivax infections that were mostly submicroscopic, of which, approximately one-quarter harboured mature gametocytes. This pattern is likely to contribute to maintaining transmission across the region. Robust surveillance systems, molecular diagnostic tests and tailored malaria detection activities for each endemic site may prove to be imperative in accelerating malaria elimination in Guatemala and possibly across all of Mesoamerica. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12936-016-1500-6) contains supplementary material, which is available to authorized users.
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spelling pubmed-50065242016-09-01 Malaria elimination challenges in Mesoamerica: evidence of submicroscopic malaria reservoirs in Guatemala Lennon, Shirley Evelyn Miranda, Adolfo Henao, Juliana Vallejo, Andres F. Perez, Julianh Alvarez, Alvaro Arévalo-Herrera, Myriam Herrera, Sócrates Malar J Research BACKGROUND: Even though malaria incidence has decreased substantially in Guatemala since 2000, Guatemala remains one of the countries with the highest malaria transmission in Mesoamerica. Guatemala is committed to eliminating malaria as part of the initiative ‘Elimination of Malaria in Mesoamerica and the Island of Hispaniola’ (EMMIE); however, it is still in the control phase. During the past decade, the government strengthened malaria control activities including mass distribution of long-lasting insecticide-impregnated bed nets, early diagnosis and prompt treatment. This study aimed to determine the prevalence of malaria, including gametocytes, in three areas of Guatemala using active case detection (ACD) and quantitative polymerase chain reaction (qPCR). METHODS: Cross-sectional surveys were conducted in three departments with varying transmission intensities: Escuintla, Alta Verapaz and Zacapa. Blood samples from 706 volunteers were screened for malaria using microscopy and qPCR which was also used to determine the prevalence of gametocytes among infected individuals. Results were collected and analysed using REDCap and R Project, respectively. RESULTS: Malaria was diagnosed by microscopy in only 2.8 % (4/141) of the volunteers from Escuintla. By contrast, qPCR detected a prevalence of 7.1 % (10/141) in the same volunteers, 8.4 % (36/429) in Alta Verapaz, and 5.9 % (8/136) in Zacapa. Overall, 7.6 % (54/706) of the screened individuals were positive, with an average parasitaemia level of 40.2 parasites/μL (range 1–1133 parasites/μL) and 27.8 % carried mature gametocytes. Fifty-seven percent (31/54) of qPCR positive volunteers were asymptomatic and out of the 42.6 % of symptomatic individuals, only one had a positive microscopy result. CONCLUSIONS: This study found a considerable number of asymptomatic P. vivax infections that were mostly submicroscopic, of which, approximately one-quarter harboured mature gametocytes. This pattern is likely to contribute to maintaining transmission across the region. Robust surveillance systems, molecular diagnostic tests and tailored malaria detection activities for each endemic site may prove to be imperative in accelerating malaria elimination in Guatemala and possibly across all of Mesoamerica. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12936-016-1500-6) contains supplementary material, which is available to authorized users. BioMed Central 2016-08-30 /pmc/articles/PMC5006524/ /pubmed/27577992 http://dx.doi.org/10.1186/s12936-016-1500-6 Text en © The Author(s) 2016 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
Lennon, Shirley Evelyn
Miranda, Adolfo
Henao, Juliana
Vallejo, Andres F.
Perez, Julianh
Alvarez, Alvaro
Arévalo-Herrera, Myriam
Herrera, Sócrates
Malaria elimination challenges in Mesoamerica: evidence of submicroscopic malaria reservoirs in Guatemala
title Malaria elimination challenges in Mesoamerica: evidence of submicroscopic malaria reservoirs in Guatemala
title_full Malaria elimination challenges in Mesoamerica: evidence of submicroscopic malaria reservoirs in Guatemala
title_fullStr Malaria elimination challenges in Mesoamerica: evidence of submicroscopic malaria reservoirs in Guatemala
title_full_unstemmed Malaria elimination challenges in Mesoamerica: evidence of submicroscopic malaria reservoirs in Guatemala
title_short Malaria elimination challenges in Mesoamerica: evidence of submicroscopic malaria reservoirs in Guatemala
title_sort malaria elimination challenges in mesoamerica: evidence of submicroscopic malaria reservoirs in guatemala
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5006524/
https://www.ncbi.nlm.nih.gov/pubmed/27577992
http://dx.doi.org/10.1186/s12936-016-1500-6
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