Zwetyenga J, Rogier C, Spiegel A, Fontenille D, Trape J F, Mercereau-Puijalon O
Unité d'Immunologie Moléculaire des Parasites, Institut Pasteur, Paris, France.
Trans R Soc Trop Med Hyg. 1999 Jul-Aug;93(4):375-80. doi: 10.1016/s0035-9203(99)90122-0.
Prolonged carriage of Plasmodium falciparum in humans during the dry season is critical for parasite survival, as the infected subjects constitute a major reservoir in the absence of transmission. Yet, very little is known about the host/parasite interactions contributing to parasite persistence. In order to study the characteristics of P. falciparum infections during the dry season, we have genotyped parasites collected from untreated, asymptomatic individuals during 3 cross-sectional surveys conducted during the dry season in Ndiop, a Senegalese village with seasonal, mesoendemic malaria. Monthly entomological surveillance did not detect any transmission during that period. Parasite prevalence decreased markedly in the children aged < 7 years after 7 months of undetected transmission, but was stable in older children and adults throughout the dry season. In all chronically infected individuals, infection complexity remained stable, but there were substantial fluctuations of individual genotype(s), reflecting complex dynamics of multiple-clone infections during chronic asymptomatic parasite carriage. This fluctuation resulted in changes in the msp1 and msp2 allelic distribution within the cohort after 7 months of undetected transmission, contrasting with the stability observed during the preceding rainy season in that village.
在旱季，恶性疟原虫在人体中的长期携带对于寄生虫的存活至关重要，因为在没有传播的情况下，受感染的个体构成了主要的储存宿主。然而，对于导致寄生虫持续存在的宿主/寄生虫相互作用却知之甚少。为了研究旱季期间恶性疟原虫感染的特征，我们对在旱季期间于恩迪奥普（Ndiop）进行的3次横断面调查中从未经治疗的无症状个体采集的寄生虫进行了基因分型，恩迪奥普是塞内加尔一个季节性中度流行疟疾的村庄。在此期间，每月的昆虫学监测未发现任何传播。在7个月未检测到传播后，<7岁儿童中的寄生虫患病率显著下降，但在整个旱季，大龄儿童和成人中的患病率保持稳定。在所有慢性感染个体中，感染复杂性保持稳定，但个体基因型存在大幅波动，反映了慢性无症状寄生虫携带期间多克隆感染的复杂动态。这种波动导致在7个月未检测到传播后，队列中msp1和msp2等位基因分布发生变化，这与该村庄前一个雨季观察到的稳定性形成对比。
