Stewart Lindsay B, Escolar Elena Lantero, Philpott James, Claessens Antoine, Amambua-Ngwa Alfred, Conway David J
Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel St, London, WC1E 7HT, UK.
LPHI, MIVEGEC, INSERM, CNRS, IRD, University of Montpellier, Montpellier, France.
Sci Rep. 2025 Jan 3;15(1):666. doi: 10.1038/s41598-024-82916-4.
The significance of multiplication rate variation in malaria parasites needs to be determined, particularly for Plasmodium falciparum, the species that causes most virulent infections. To investigate this, parasites from cases presenting to hospital in The Gambia and from local community infections were culture-established and then tested under exponential growth conditions in a standardised six-day multiplication rate assay. The multiplication rate distribution was lower than seen previously in clinical isolates from another area in West Africa where infection is more highly endemic. Multiplication rates were higher in cultured isolates derived from hospital cases (N = 23, mean = 2.9-fold per 48 h) than in those from community infections (N = 11, mean = 1.8-fold)(Mann-Whitney P < 0.001). There was a positive correlation between levels of parasitaemia in peripheral blood of sampled individuals and multiplication rates of the isolates in culture (Spearman's rho = 0.45, P = 0.017). There was no significant difference between isolates containing single parasite genotypes or multiple genotypes at the time of assay, suggesting that parasites do not modify their multiplication rates in response to the presence of different genotypes. It will be important to uncover the mechanisms of this intrinsic multiplication rate variation, and to also investigate the epidemiological distribution and potential associations with infection phenotypes in other populations.
疟原虫增殖率变化的意义有待确定，尤其是对于恶性疟原虫，这种疟原虫会引发最具毒性的感染。为了对此进行研究，从冈比亚住院病例以及当地社区感染中获取的疟原虫进行了培养建立，然后在标准化的六天增殖率测定中，于指数生长条件下进行测试。增殖率分布低于此前在西非另一个感染更为高发地区的临床分离株中所观察到的情况。来自医院病例的培养分离株（N = 23，平均每48小时为2.9倍）的增殖率高于来自社区感染的分离株（N = 11，平均为1.8倍）（曼-惠特尼检验P < 0.001）。采样个体外周血中的寄生虫血症水平与培养物中分离株的增殖率之间存在正相关（斯皮尔曼相关系数rho = 0.45，P = 0.017）。在测定时，含有单一寄生虫基因型或多种基因型的分离株之间没有显著差异，这表明疟原虫不会因不同基因型的存在而改变其增殖率。揭示这种内在增殖率变化的机制，以及研究其在其他人群中的流行病学分布和与感染表型的潜在关联将具有重要意义。
