Unexpected high circulation of Plasmodium vivax in asymptomatic children from Kédougou, southeastern Senegal

Malaria Journal

Research

Amadou A. Sall¹  Bacary D. Sadio¹  Ousmane Faye¹  Abdourahmane Sow²  Ronald Perraut³  Oulimata Niang³  Makhtar Niang³  Fode Diop³  Aissatou Toure-Balde³  Mawlouth Diallo⁴ 

[1] Arbovirus and Viral Hemorrhagic Fevers Unit, Institut Pasteur de Dakar, Dakar, Senegal;Arbovirus and Viral Hemorrhagic Fevers Unit, Institut Pasteur de Dakar, Dakar, Senegal;West African Health Organization, Ouagadougou, Burkina Faso;Immunology Unit, Institut Pasteur de Dakar, Dakar, Senegal;Medical Entomology Unit, Institut Pasteur de Dakar, Dakar, Senegal;

关键词: Malaria;    Plasmodium falciparum;    Plasmodium vivax;    ELISA;    IgG;    MSP1;    Asymptomatic carriage;    Parasite circulation;   

DOI  :  10.1186/s12936-017-2146-8

 received in 2017-08-14, accepted in 2017-12-18,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundMalaria in Senegal is due essentially to infections by Plasmodium falciparum and, to a lesser extent to Plasmodium malariae and Plasmodium ovale. By the use of molecular methods, detection of Plasmodium vivax has been recently reported in the region of Kedougou, raising the question of appraisal of its potential prevalence in this setting.MethodsA retrospective serological study was carried out using 188 samples taken from 2010 to 2011 in a longitudinal school survey during which 48 asymptomatic children (9–11 years) were recruited. Four collections of samples collected during two successive dry and rainy seasons were analysed for antibody responses to P. vivax and P. falciparum. Recombinant P. falciparum and P. vivax MSP1 antigens and total P. falciparum schizont lysate from African 07/03 strain (adapted to culture) were used for ELISA. Nested PCR amplification was used for molecular detection of P. vivax.ResultsA surprising high prevalence of IgG responses against P. vivax MSP1 was evidenced with 53% of positive samples and 58% of the individuals that were found positive to this antigen. There was 77% of responders to P. falciparum outlined by 63% of positive samples. Prevalence of responders did not differ as function of seasons. Levels of antibodies to P. falciparum fluctuated with significant increasing between dry and rainy season (P < 0.05), contrary to responses to P. vivax. There was a significant reciprocal relationship (P < 10−3) between antibody responses to the different antigens, but with weak coefficient of correlation (Rho around 0.3) underlining a variable profile at the individual level. Clear molecular signature was found in positive IgG to P. vivax msp1 samples by PCR.ConclusionThis cross-sectional longitudinal study highlights the unexpected high circulation of P. vivax in this endemic area. Sero-immunology and molecular methods are powerful additive tools to identify endemic sites where relevant control measures have to be settled and monitored.

【 授权许可】

CC BY   
© The Author(s) 2017