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

Parasites & Vectors

Anne C. G. Almeida¹  Wuelton M. Monteiro¹  Larissa W. Brasil¹  Sheila Vitor-Silva¹  Marcus V. G. Lacerda¹  Erick F. G. Figueiredo¹  Marcelo A. M. Brito¹  Vanderson S. Sampaio²  Ivo Mueller³  Andrea Kuehn³  Quique Bassat³  Wanderli P. Tadei⁴  Ingrid Felger⁵  Arthur J. M. Castro⁶ 

[1] Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD);Fundação de Vigilância em Saúde do Amazonas, Sala de Análise de Situação em Saúde;ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona;Instituto Nacional de Pesquisas da Amazônia (INPA);Swiss Tropical and Public Health Institute;Universidade do Estado do Amazonas (UEA);

关键词: Malaria;    Plasmodium vivax;    Asymptomatic infection;    Submicroscopic infection;    Gametocyte carriage;   

DOI  :  10.1186/s13071-018-2787-7

来源: DOAJ

【 摘 要 】

Abstract 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.

【 授权许可】

Unknown