Microsatellite genotyping of Plasmodium vivax infections and their relapses in pregnant and non-pregnant patients on the Thai-Myanmar border

Malaria Journal

Research

Supinya Thanapongpichat¹  Mallika Imwong²  Georges Snounou³  Nicholas PJ Day⁴  Nicholas J White⁴  Francois Nosten⁵  Rose McGready⁶  Christine Luxemburger⁷ 

[1] Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;INSERM UMR-S 945, F-75013, Paris, France;Université Paris 6, Pierre & Marie Curie, Faculté de Médecine Pitié-Salpêtrière, Paris, France;Mahidol Oxford Tropical Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;Centre for Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, UK;Shoklo Malaria Research Unit, Mae Sot, Tak Province, Thailand;Shoklo Malaria Research Unit, Mae Sot, Tak Province, Thailand;Centre for Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, UK;Shoklo Malaria Research Unit, Mae Sot, Tak Province, Thailand;Sanofi Pasteur, Lyon, France;

关键词: Genetic diversity;    Malaria;    Plasmodium vivax;    Pregnancy;    Relapse;   

DOI  :  10.1186/1475-2875-12-275

 received in 2013-04-03, accepted in 2013-07-30,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundPlasmodium vivax infections in pregnancy are associated with low birth weight and anaemia. This parasites species is also characterised by relapses, erythrocytic infections initiated by the activation of the dormant liver stages, the hypnozoites, to mature. Genotyping of P. vivax using microsatellite markers has opened the way to comparative investigations of parasite populations. The aim of the study was to assess whether there were any differences between the parasites found in pregnant and non-pregnant patients, and/or between the admission infections and recurrent episodes during follow-up.MethodsBlood samples were collected from 18 pregnant and 18 non-pregnant patients, who had at least two recurrent episodes during follow-up, that were recruited in two previous trials on the efficacy of chloroquine treatment of P. vivax infections on the Thai-Myanmar border. DNA was purified and the P. vivax populations genotyped with respect to eight polymorphic microsatellite markers. Analyses of the genetic diversity, multiplicity of infection (MOI), and a comparison of the genotypes in the samples from each patient were conducted.ResultsThe P. vivax parasites present in the samples exhibited high genetic diversity (6 to 15 distinct allelic variants found for the 8 loci). Similar expected heterozygosity (He) values were obtained for isolates from pregnant (0.837) and non-pregnant patients (0.852). There were modest differences between the MOI values calculated for both admission and recurrence samples from the pregnant patients (2.00 and 2.05, respectively) and the equivalent samples from the non-pregnant patients (1.67 and 1.64, respectively). Furthermore, the mean number of distinct alleles enumerated in the admission samples from the pregnant (6.88) and non-pregnant (7.63) patients were significantly lower than that found in the corresponding recurrent episodes samples (9.25 and 9.63, respectively).ConclusionsThe P. vivax populations circulating in inhabitants along the Thai-Myanmar border, an area of low malaria transmission, displayed high genetic diversity. A subtle increase in the multiplicity of P. vivax infections in pregnant patients suggests a higher susceptibility to infection. The higher allelic diversity in the relapse as compared to the admission samples in both patient groups is consistent with the hypothesis that a febrile episode promotes the activation of hypnozoites.

【 授权许可】

Unknown   
© Thanapongpichat et al.; licensee BioMed Central Ltd. 2013. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.