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

2005年至2006年疟疾流行病学研究期间，在柬埔寨和印度尼西亚发现4例恶性疟原虫(PF)，配子体形态很薄。对18S核糖体RNA基因的分析表明，它们属于从越南发现的PF变异型，在分子诊断的靶区具有相同的序列变异。因此，在本研究中，我们通过对18S核糖体RNA基因的分析，对Pf变异体是否属于Pf变异体进行了类似的流行病学研究。此外，我们的研究还有另一个目标：在Pf变种或普通Pf(也包括间日浆原虫；PV)的体外培养中，从配子体到子孢子。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名感染Pf变种的患者，但这些血液中不含配子体。此外，我们检测到1例患者感染了PV配子体，但体外培养试验失败。2008年，我们发现2例患者感染了普通PF的配子体，并尝试了配子体的体外培养。此外，我们在柬埔寨检测到1名患者感染了PV配子体。然而，所有这些体外培养的试验也都失败了。2009年，在印度尼西亚和越南没有发现感染Pf变种的患者。因此，普通PF和变异PF的配子体形态是否不同，目前尚不清楚。

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.