Molecular epidemiological study on the variant type of Plasmodium falciparum and trial for in vitro culture of gametocytes

2005 - 2006年疟疾流行病学研究中，在柬埔寨和印度尼西亚4例患者中发现配子细胞形态极薄的恶性疟原虫（Pf）。18S核糖体RNA基因分析表明，它们属于越南产Pf的变异型，在分子诊断靶区具有相同的序列变异。因此，在本研究中，我们通过分析18S核糖体RNA基因，继续对Pf变型进行类似的流行病学研究，无论配子体形状奇怪是否属于Pf变型。此外，我们的研究还有另一个目的；在野外培养从配子体到变异或普通Pf（也称间日疟原虫的配子体；Pv）孢子子的试验。我们从2007年4月开始在印度尼西亚、柬埔寨、越南和泰国调查疟疾。2007年，我们在柬埔寨发现了2例感染变型Pf的患者，但这些血液不含配子体。另外，我们检测到1例患者感染Pv配子细胞，但体外培养试验失败。2008年，我们发现了2例感染普通Pf配子细胞的患者，并尝试了配子细胞的体外培养。此外，我们在柬埔寨检测到1例Pv配子体感染患者。但这些体外培养试验均以失败告终。2009年，在印度尼西亚和越南没有发现感染变异Pf的患者。因此，目前尚不清楚普通Pf与变异Pf配子体形态是否有差异。

During epidemiological study on malaria from 2005 to 2006, Plasmodium falciparum (Pf) with very thin morphology of gametocytes was found in 4 patients in Cambodia and Indonesia. Analysis of 18S ribosomal RNA gene indicated that they are belonging to the variant type of Pf detected from Vietnam, and they had the same sequence variation at the target region for molecular diagnosis. Therefore, in this study, we continued similar epidemiological study on the variant Pf whether the strange shape of gametocytes belongs to the variant Pf or not by analyzing the 18S ribosomal RNA gene. In addition, our study had another aim ; a trial to cultivate in vitro from gametocytes to sporozoites in the variant or ordinary Pf (also gametocytes of Plasmdium vivax ; Pv) at the field.We surveyed malaria in Indonesia, Cambodia, Vietnam and Thailand from April 2007. In 2007, we found 2 patients infected with the variant Pf in Cambodia, but these bloods did not contain gametocytes. In addition, we detected 1 patient infected with Pv gametocytes, but trial of in vitro culture was failed. In 2008, we found 2 patients infected with gametocytes of the ordinary Pf, and tried in vitro culture of gametocytes. Furthermore, we detected 1 patient infected with Pv gametocytes in Cambodia. However, all these trials of in vitro culture were also failed. In 2009, no patient infected with the variant Pf was found in Indonesia and Vietnam. Therefore, it is still not clear whether morphology of gametocytes is different or not between the ordinary Pf and the variant Pf.