Getachew Sisay, To Sheren, Trimarsanto Hidayat, Thriemer Kamala, Clark Taane G, Petros Beyene, Aseffa Abraham, Price Ric N, Auburn Sarah
College of Natural Sciences, Addis Ababa University, P.O. Box 52, Addis Ababa, Ethiopia; Armauer Hansen Research Institute, P.O. Box 1005, Jimma Road, Addis Ababa, Ethiopia.
Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, NT 0810, Australia.
PLoS One. 2015 Oct 15;10(10):e0140780. doi: 10.1371/journal.pone.0140780. eCollection 2015.
P. vivax is an important public health burden in Ethiopia, accounting for almost half of all malaria cases. Owing to heterogeneous transmission across the country, a stronger evidence base on local transmission dynamics is needed to optimise allocation of resources and improve malaria interventions.
In a pilot evaluation of local level P. vivax molecular surveillance in southern Ethiopia, the diversity and population structure of isolates collected between May and November 2013 were investigated. Blood samples were collected from microscopy positive P. vivax patients recruited to clinical and cross-sectional surveys from four sites: Arbaminch, Halaba, Badawacho and Hawassa. Parasite genotyping was undertaken at nine tandem repeat markers. Eight loci were successfully genotyped in 197 samples (between 36 and 59 per site). Heterogeneity was observed in parasite diversity and structure amongst the sites. Badawacho displayed evidence of unstable transmission, with clusters of identical clonal infections. Linkage disequilibrium in Badawacho was higher (IAS = 0.32, P = 0.010) than in the other populations (IAS range = 0.01-0.02) and declined markedly after adjusting for identical infections (IAS = 0.06, P = 0.010). Other than Badawacho (HE = 0.70), population diversity was equivalently high across the sites (HE = 0.83). Polyclonal infections were more frequent in Hawassa (67%) than the other populations (range: 8-44%). Despite the variable diversity, differentiation between the sites was low (FST range: 5 x 10-3-0.03).
Marked variation in parasite population structure likely reflects differing local transmission dynamics. Parasite genotyping in these heterogeneous settings has potential to provide important complementary information with which to optimise malaria control interventions.
间日疟原虫是埃塞俄比亚一项重大的公共卫生负担，占所有疟疾病例的近一半。由于该国各地传播情况存在异质性，需要更有力的关于当地传播动态的证据基础，以优化资源分配并改善疟疾防治措施。
在埃塞俄比亚南部对当地间日疟原虫分子监测进行的试点评估中，调查了2013年5月至11月期间收集的分离株的多样性和种群结构。从参与临床和横断面调查的四个地点（阿巴明奇、哈拉巴、巴达瓦乔和霍瓦萨）招募的间日疟原虫镜检阳性患者中采集血样。在九个串联重复标记处进行寄生虫基因分型。在197份样本（每个地点36至59份）中成功对八个位点进行了基因分型。各地点间在寄生虫多样性和结构方面存在异质性。巴达瓦乔显示出传播不稳定的迹象，存在相同克隆感染的聚集情况。巴达瓦乔的连锁不平衡高于其他种群（IAS = 0.32，P = 0.010），在对相同感染进行校正后显著下降（IAS = 0.06，P = 0.010）。除巴达瓦乔（HE = 0.70）外，各地点的种群多样性同样较高（HE = 0.83）。霍瓦萨的多克隆感染比其他种群更频繁（67%）（范围：8% - 44%）。尽管多样性存在差异，但各地点之间的分化程度较低（FST范围：5×10⁻³ - 0.03）。
寄生虫种群结构的显著差异可能反映了不同的当地传播动态。在这些异质性环境中进行寄生虫基因分型有可能提供重要的补充信息，用于优化疟疾控制干预措施。
