High prevalence of sub-microscopic infections in Colombia

Malaria Journal

Research

Yoldy Benavides¹  Álvaro Álvarez¹  Sócrates Herrera²  Myriam Arévalo-Herrera³  Andres F Vallejo⁴  Juan Pablo Quintero⁴  Julio Padilla⁵  Pablo E Chaparro⁶ 

[1] Caucaseco Scientific Research Center, Cali, Colombia;Caucaseco Scientific Research Center, Cali, Colombia;Latin American Center for Malaria Research, Cali, Colombia;Caucaseco Scientific Research Center, Cali, Colombia;Latin American Center for Malaria Research, Cali, Colombia;School of Health, Universidad del Valle, Cali, Colombia;Malaria Vaccine and Drug Development Centre, Cali, Colombia;Ministry of Health and Social Protection of Colombia, Bogotá, Colombia;National Institute of Health of Colombia, Bogotá, Colombia;

关键词: Malaria;    Malaria Transmission;    Malaria Prevalence;    Mass Drug Administration;    Malaria Elimination;   

DOI  :  10.1186/s12936-015-0711-6

 received in 2015-03-03, accepted in 2015-04-23,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundMalaria transmission in Latin America is typically characterized as hypo-endemic and unstable with ~170 million inhabitants at risk of malaria infection. Although Colombia has witnessed an important decrease in malaria transmission, the disease remains a public health problem with an estimated ~10 million people currently living in areas with malaria risk and ~61,000 cases reported in 2012. This study aimed to establish the malaria prevalence in three endemic regions of Colombia to aid in designing new interventions for malaria elimination.MethodsA cross-sectional survey was conducted in three regions of Colombia with different malaria epidemiological profiles: Tierralta (Ta), Tumaco (Tu) and Buenaventura (Bv). The Annual Parasite Index (API) was 10.7, 6.9 and 3.1, respectively. Participants were asked to respond to a sociodemographic questionnaire and then were bled to determine the Duffy genotype and the prevalence of malaria infection by microscopy and quantitative real-time PCR (qPCR).ResultsThe study was conducted between October 2011 and January 2012. Eight sentinel sites with 1,169 subjects from 267 households were included. The overall prevalence of sub-microscopic infections measured by thick blood smear (TBS) was 0.3% (n = 4) whereas by qPCR it was 9.7% (n = 113), with a greater proportion (13%) in 40-50 years old individuals. Furthermore, different regions displayed different prevalence of sub-microscopic infections: Bv 12%, Ta 15%, and Tu 4%. From these 113 samples (qPCR), 74% were positive for P. vivax and 22% for P. falciparum, and 4% were mixed infections, which correlates to the overall parasite prevalence in Colombia. This study showed that in the southern Pacific coast of Colombia (Bv and Tu), around 56% of the population have a Duffy-negative genotype, compared to the northern region (Ta) where the percentage of Duffy-negative genotype is around 3%.ConclusionsSub-microscopic infections are prevalent across different regions in Colombia, particularly in areas with relatively low transmission intensity. The poor microscopy results suggest the need for more sensitive diagnostic tools for detection of sub-microscopic infections. This study underscores the importance of conducting active case surveillance to more accurately determine malaria incidence, and highlights the need for updating the malaria guidelines to track and treat sub-microscopic malaria infections.

【 授权许可】

Unknown   
© Vallejo et al.; licensee BioMed Central. 2015. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. 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.