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Abstract：
BACKGROUND: Travel-related malaria in non-endemic areas returning from endemic areas presents important challenges to diagnosis and treatment. Imported malaria to newly malaria-free countries poses further threats of malaria re-introduction and potential resurgence. For those traveling to places with high Plasmodium falciparum prevalence, prophylaxis against this parasite is recommended, whereas causal prophylaxis against relapsing malaria is often overlooked.
METHODS: We analyzed a cluster of imported malaria among febrile patients in Shanglin County, Guangxi Province, China, who had recent travel histories to Western and Central Africa. Malaria was diagnosed by microscopy and subsequently confirmed by species- and subspecies-specific PCR. Plasmodium vivax was genotyped using a barcode consisting of 42 single nucleotide polymorphisms.
RESULTS: Investigations of 344 PCR-confirmed malaria cases revealed that in addition to Plasmodium falciparum being the major parasite species, the relapsing parasites Plasmodium ovale and P. vivax accounted for ~40% of these imported cases. Of the 114 P. ovale infections, 65.8% and 34.2% were P. ovale curtisi and P. ovale wallikeri, respectively, with the two subspecies having a ~2:1 ratio in both Western and Central Africa. Phylogenetic analysis of 14 P. vivax isolates using a genetic barcode demonstrated that 11 formed a distinct clade from P. vivax populations from Eastern Africa.
CONCLUSIONS: This study provides support for active P. vivax transmission in areas with the predominant Duffy-negative blood group. With relapsing malaria making a substantial proportion of the imported malaria, causal prophylaxis should be advocated to travelers with a travel destination to Western and Central Africa.
METHODS: We analyzed a cluster of imported malaria among febrile patients in Shanglin County, Guangxi Province, China, who had recent travel histories to Western and Central Africa. Malaria was diagnosed by microscopy and subsequently confirmed by species- and subspecies-specific PCR. Plasmodium vivax was genotyped using a barcode consisting of 42 single nucleotide polymorphisms.
RESULTS: Investigations of 344 PCR-confirmed malaria cases revealed that in addition to Plasmodium falciparum being the major parasite species, the relapsing parasites Plasmodium ovale and P. vivax accounted for ~40% of these imported cases. Of the 114 P. ovale infections, 65.8% and 34.2% were P. ovale curtisi and P. ovale wallikeri, respectively, with the two subspecies having a ~2:1 ratio in both Western and Central Africa. Phylogenetic analysis of 14 P. vivax isolates using a genetic barcode demonstrated that 11 formed a distinct clade from P. vivax populations from Eastern Africa.
CONCLUSIONS: This study provides support for active P. vivax transmission in areas with the predominant Duffy-negative blood group. With relapsing malaria making a substantial proportion of the imported malaria, causal prophylaxis should be advocated to travelers with a travel destination to Western and Central Africa.
摘要：
背景：从流行地区返回的非流行地区的旅行相关疟疾对诊断和治疗提出了重要挑战。向新无疟疾国家输入的疟疾构成了疟疾重新传入和潜在复苏的进一步威胁。对于那些前往恶性疟原虫患病率高的地方的人，建议预防这种寄生虫，而复发性疟疾的因果预防往往被忽视。
方法：我们分析了上林县高热患者中的一组输入性疟疾，广西,中国,他们最近有去过西非和中非的旅行史。通过显微镜诊断出疟疾，随后通过物种和亚种特异性PCR确认。使用由42个单核苷酸多态性组成的条形码对间日疟原虫进行基因分型。
结果：对344例PCR证实的疟疾病例的调查显示，除了恶性疟原虫是主要的寄生虫种类外，复发性寄生虫卵疟原虫和间日疟原虫约占这些输入病例的40％。在114例卵卵圆瓶感染中，65.8%和34.2%分别为卵卵卵圆虫和卵圆虫。分别,在西非和中非，这两个亚种的比例约为2：1。使用遗传条形码对14个间日疟原虫分离株进行的系统发育分析表明，11个与来自东非的间日疟原虫种群形成了不同的进化枝。
结论：本研究为Duffy阴性血型占优势的地区间日疟原虫的活跃传播提供了支持。由于复发性疟疾占进口疟疾的很大一部分，应该提倡对有前往西非和中非的旅行目的地的旅行者进行因果预防。
方法：我们分析了上林县高热患者中的一组输入性疟疾，广西,中国,他们最近有去过西非和中非的旅行史。通过显微镜诊断出疟疾，随后通过物种和亚种特异性PCR确认。使用由42个单核苷酸多态性组成的条形码对间日疟原虫进行基因分型。
结果：对344例PCR证实的疟疾病例的调查显示，除了恶性疟原虫是主要的寄生虫种类外，复发性寄生虫卵疟原虫和间日疟原虫约占这些输入病例的40％。在114例卵卵圆瓶感染中，65.8%和34.2%分别为卵卵卵圆虫和卵圆虫。分别,在西非和中非，这两个亚种的比例约为2：1。使用遗传条形码对14个间日疟原虫分离株进行的系统发育分析表明，11个与来自东非的间日疟原虫种群形成了不同的进化枝。
结论：本研究为Duffy阴性血型占优势的地区间日疟原虫的活跃传播提供了支持。由于复发性疟疾占进口疟疾的很大一部分，应该提倡对有前往西非和中非的旅行目的地的旅行者进行因果预防。
