Molecular typing reveals substantial Plasmodium vivax infection in asymptomatic adults in a rural area of Cameroon
Molecular typing reveals substantial Plasmodium vivax infection in asymptomatic adults in a rural area of Cameroon
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DOI：
10.1186/1475-2875-13-170
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发表时间：
2014-05-03
期刊：
影响因子：
3
通讯作者：
Haldar, Kasturi
中科院分区：
文献类型：
--
作者：
Fru-Cho, Jerome;Bumah, Violet V.;Haldar, Kasturi
工作背景：喀麦隆的疟疾是由恶性疟原虫感染引起的，其次是三日疟原虫和卵形疟原虫感染，但间日疟原虫很少。最近的一份报告表明，研究区域周围存在“间日疟原虫样”感染，但尚未得到证实。因此，分子和抗原分型，以调查无症状的成年居民在Bolifamba.Methods：横断面研究，从2008年7月至2009年10月间日疟原虫和达菲的患病率。所有的寄生虫物种的状态，确定了巢式PCR在269血液样本收集。还通过快速卡片测定定性确定每名受试者的恶性疟原虫和间日疟原虫抗MSP/CSP抗体状态。从感染三种寄生虫的样品中提取寄生虫DNA，纯化并测序。还通过测序确定了感染间日疟原虫的12名受试者的Duffy抗原状态。在硅网络为基础的工具被用来分析序列数据的相似性和匹配的参考序列在公共DNAdatabases.Results：在269个人的疟疾寄生虫的总体患病率为32.3%（87），通过PCR测定。值得注意的是，在Duffy受体阳性（50%，6/12）和阴性（50%，6/12）的个体中，通过PCR和血涂片显微镜检查确定，14.9%（13/87）的感染完全或伴随由间日疟原虫引起。在一个感染个体中检测到恶性疟原虫、间日疟原虫和三日疟原虫的三重感染。在72.1%（194/269）的样本中检测到抗MSP/CSP抗体，表明通过蚊子叮咬高和持续暴露于感染，讨论：这些数据提供了第一个分子证据，间日疟原虫在达菲阳性和阴性的喀麦隆人，并表明，可能有一个显着的流行间日疟原虫感染比预期的研究领域。未调查间日疟原虫病例是否为输入性病例或由于创始者效应的扩大所致。尽管如此，间日疟原虫的存在可能会使控制工作复杂化，如果这些寄生虫成为hypnozoitic或潜伏的肝stage.Conclusions：这些数据强烈表明，间日疟原虫是喀麦隆西南地区的地方病，并应考虑到在设计疟疾控制策略。
Background: Malaria in Cameroon is due to infections by Plasmodium falciparum and, to a lesser extent, Plasmodium malariae and Plasmodium ovale, but rarely Plasmodium vivax. A recent report suggested "Plasmodium vivax-like" infections around the study area that remained unconfirmed. Therefore, molecular and antigenic typing was used to investigate the prevalence of P. vivax and Duffy in asymptomatic adults resident in Bolifamba.Methods: A cross-sectional study was conducted from July 2008 to October 2009. The status of all parasite species was determined by nested PCR in 269 blood samples collected. The P. falciparum and P. vivax anti-MSP/CSP antibody status of each subject was also determined qualitatively by a rapid card assay. Parasite DNA was extracted from a sample infected with three parasite species, purified and sequenced. The Duffy antigen status of 12 subjects infected with P. vivax was also determined by sequencing. In silico web-based tools were used to analyse sequence data for similarities and matches to reference sequences in public DNA databases.Results: The overall malaria parasite prevalence in 269 individuals was 32.3% (87) as determined by PCR. Remarkably, 14.9% (13/87) of infections were caused either exclusively or concomitantly by P. vivax, established both by PCR and microscopic examination of blood smears, in individuals both positive (50%, 6/12) and negative (50%, 6/12) for the Duffy receptor. A triple infection by P. falciparum, P. vivax and P. malariae, was detected in one infected individual. Anti-MSP/CSP antibodies were detected in 72.1% (194/269) of samples, indicating high and continuous exposure to infection through mosquito bites.Discussion: These data provide the first molecular evidence of P. vivax in Duffy positive and negative Cameroonians and suggest that there may be a significant prevalence of P. vivax infection than expected in the study area. Whether the P. vivax cases were imported or due to expansion of a founder effect was not investigated. Notwithstanding, the presence of P. vivax may complicate control efforts if these parasites become hypnozoitic or latent as the liver stage.Conclusions: These data strongly suggest that P. vivax is endemic to the south-west region of Cameroon and should be taken into account when designing malaria control strategies.