间日疟原虫MSP-1和CSP基因遗传多样性的分析

目的 比较间日疟原虫两种主要分子标志(MSP-1和CSP)的遗传多样性。方法 分别用MSP-1和CSP基因分型方法鉴定间日疟原虫现场分离株，并进行基因多态性比较和分析。结果 共检测32份海南省现场确诊的间日疟病人血样，MSP-1等位基因型混合感染率为18．75％，平均克隆数1．16；CSP基因型混合感染率为35．29％，平均克隆数为1．47。如果同时考虑两种基因型，混合感染率则为50．0％。空间对应分析发现，热带族与Sal-1型关系密切，PvⅡ型与重组Ⅲ型分布靠近，其他基因型则较分散。结论 同时用MSF-1和CSP两种分子标志检测间日疟原虫，其基因型混合感染率高于用单一标志检测，两种标志检测结果存在一定对应关系。     

中缅边境恶性疟原虫裂殖子表面蛋白1,2基因多态性研究

目的对云南省及边境地区恶性疟原虫的裂殖子表面蛋白(merozoite surface protein,MSP)1,2基因进行分型研究,确定其等位基因的类型和分布特征,结合当地的恶性疟原虫株流行病学信息,为该地区疟疾的防治提供科学依据。方法从缅甸拉咱、那威和我国云南省西双版纳勐腊、德宏瑞丽、保山腾冲采集恶性疟患者血样。用巢式PCR(nest-PCR)扩增18S rRNA基因,确定感染疟原虫的种类。对检测为恶性疟原虫以及恶性疟原虫/间日疟原虫混合感染的样本,进行恶性疟原虫MSP-1、MSP-2基因的扩增并作测序、验证与序列分析。结果共采集89份恶性疟样本,经18S rRNA基因检测,确定间日疟9例,恶性疟78例和混合感染2例。在检测为恶性疟和混合感染的80份样本中,69例扩增出MSP-1基因片段,77例扩增出MSP-2基因片段。在MSP-1等位基因中,以MAD20型68.75%为主,RO33型23.75%和K1型20.00%次之。来源于勐腊的样本均未检出RO33型和K1型;MSP-2等位基因FC27型和3D7型的感染率均为91.25%,无明显的优势虫株;MSP-1和MSP-2基因多克隆样本所占百分比与多重性感染(multiplicity of infection,MOI)分别为22.50%、1.81和86.25%、3.51。MSP-1和MSP-2等位基因目的片段多样性与其原虫密度之间存在相关性(Spearman's r=0.496,P0.05;Spearman's r=0.240,P0.05)。MSP-1和MSP-2等位基因测序结果表明,在FC27型基因序列3′端发现1个新的APK序列,在3D7基因型序列中检测到1个新的PAT重复序列和其它19个新的序列。结论云南省及边境地区恶性疟原虫分离株MSP-1等位基因存在MAD20型、K1型和RO33型3种类型,以MAD20型为优势虫株,勐腊样本未发现K1型和RO33型;MSP-2等位基因存在FC27型和3D7型2种类型,其优势均不明显。     

山东省间日疟原虫MSP-1和CSP等位基因型及同源性分析

目的分析山东省间日疟原虫MSP-1和CSP基因类型及其同源性,为病例溯源提供科学依据。方法采集2011年山东省报告的12例间日疟患者血样,提取疟原虫基因组DNA;分别根据间日疟原虫MSP-1和CSP基因序列设计引物,进行巢式PCR扩增、酶切、测序、序列比对及同源性分析。结果 12份间日疟患者血样MSP-1基因全部出现470bp扩增条带以及350、120 bp酶切片段,均为Sal-1型;MSP-1进化树分析显示,9份省内感染者样品序列同属一个分枝,1份印度感染者样品序列与印度分离株位于同一分枝。12份间日疟患者样品CSP基因均包含GDRA(D/A)GQPA序列,为PV-Ⅰ型,其中10份省内感染者和1份广东感染者样品CSP基因出现560~840 bp和150~230 bp两种扩增条带,为PV-Ⅰ型温带族,1份在印度感染者样品CSP基因仅出现560~840 bp条带,为PV-Ⅰ型热带族。CSP进化树表明,10份省内感染者及1份广东感染者样品序列同属一个分枝,1份在印度感染者样品序列与印度和印度尼西亚分离株位于同一分枝。结论山东省本地感染间日疟原虫MSP-1基因型均为Sal-1型,CSP基因型均为PV-Ⅰ型温带族,本地虫株具有较强的基因同源性。     

我国不同疟区间日疟原虫裂殖子表面蛋白1(PvMSP-1)基因多态性研究

目的　了解我国不同疟疾流行区间日疟原虫裂殖子表面蛋白 - 1基因多态性及其分布。方法　用套式PCR扩增间日疟原虫现场分离株MSP - 1第五多态区 (ICB5 -ICB6 )基因片段 ,部分样本进行序列测定、分析和比对。结果　 82份间日疟原虫现场分离株扩增出 4 70bp片段 5 0份 ,4 0 0bp片段 39份 ,其中 7份为两种片段的混合型。海南分离株混合型为 2 0 %(6 / 30 ) ,平均克隆数为 1 2 0 (36 / 30 ) ,安徽分离株混合型仅为 2 3% ,平均克隆数 1 0 2。对 33份样本进行序列测定 ,Sal- 1型17份 ,Belem型 2份 ,12份重组型 (Ⅲ型 )和朝鲜型 2份为我国新发现基因型。结论　我国间日疟原虫PvMSP - 1存在 4种不同的等位基因型 ,以Sal- 1型和重组型 (Ⅲ型 )占优势 ,南部疟区基因型比北部复杂。     

西藏林芝地区间日疟原虫PvMSP-3α多态性研究

【摘要】 目的 分析西藏林芝地区间日疟原虫遗传多态性。 方法 以间日疟原虫裂殖子表面蛋白3α（Plasmodium vivax merozoite surface protion genes 3α,PvMSP-3α）为分子标志,利用PCR-RFLP技术对西藏林芝间日疟原虫多态性进行分析。 结果 共发现2种类型的MSP-3α基因,多数为A型（90.3%）,B型较少（9.7%）,无混合感染。PCR-RFLP分析MSP-3α基因存在较低多态性。 结论 西藏林芝地区间日疟原虫的遗传多态性较低。     

间日疟原虫不同MSP-1等位基因型形态学观察

目的　比较两种不同等位基因型间日疟原虫生物学形态特征。方法　现场采集间日疟病人血样并进行基因分型 ,镜下观察形态并测量大小。结果与结论　 72份现场分离株基因分型为Sal- 1型 4 0份 ,Belem型 2 5份 ,混合感染 7份 ,均查到典型的间日疟原虫 ,6例多重感染病例均发现在海南分离株 ,多重感染与基因型混合感染无关联。测量正常红细胞、寄生红细胞、环状体以及核大小差别有显著意义 ,Belem型比Sal- 1型大 ,两种不同基因型差异的分子机制需进一步探讨     

我国华南间日疟原虫裂殖子表面蛋白1等位基因分型和序列分析

目的　了解我国间日疟原虫MSP1(PvMSP1)的等位基因类型和序列的多态性。方法　用特异的引物通过套式PCR方法体外扩增包含PvMSP1的ICB5与ICB6之间的基因片段 ,并对部分扩增产物进行序列测定和分析。结果　 2 7份间日疟原虫患者血样中 ,有 16份 (5 9 9% )扩增得到Belem型基因产物 ,2 5 (92 6 % )份扩增出Sal- 1型基因产物 ;两种不同等位基因型虫株的混合感染率为 5 1 9%。序列分析结果发现一个以前未见报告的基因内重组类型。结论　我国间日疟原虫虫株存在两种PvMSP1等位基因型 ,Sal- 1型可能是主导型 ;不同等位基因型的混合感染率较高     

问日疟原虫不同MSP-1等位基因型形态学观察

目的 比较两种不同等位基因型间日疟原虫生物学形态特征。方法 现场采集间日疟病人血样并进行基因分型，镜下观察形态并测量大小。结果与结论 72份现场分离株基因分型为Sal-1型40份，Belem型25份，混合感染7份。均查到典型的间日疟原虫，6例多重感染病例均发现在海南分离株，多重感染与基因型混合感染无关联。测量正常红细胞、寄生红细胞、环状体以及核大小差别有显著意义，Belem型比Sal-1型大，两种不同基因型差异的分子机制需进一步探讨。     

2006和2008年度安徽蒙城间日疟原虫群体遗传结构研究

目的 对2006年和2008年采自安徽蒙城的间日疟原虫群体遗传结构及其与发病率之间的关系进行研究.方法 以间日疟原虫裂殖子表面基因蛋白3α(Plasmodium vivax merozoite surface protein genes-3α,PvMSP-3α)为分子标志,利用PCR-RFLP技术对不同年度间日疟原虫群体遗传多态现象进行分析,用卡方检验比较年度间等位基因频率是否存在差异.结果 共发现了3种类型的MSP-3α基因.2006年的样本仅发现两个型:多数为A型(91.30%),少数为C型(4.35%),并有2例A和C的混合感染(4.35%);2008年样本中,仅发现A型(88.60%)和B型(11.40%),无混合感染.PCRRFLP分析MSP-3α基因存在高度多态性.卡方检验显示2006年和2008年间的差异无统计学意义.结论 安徽蒙城的间日疟原虫存在较高的遗传多态性,且遗传多态性未随疟疾疫情的下降而改变.     

辽宁省间日疟原虫环子孢子蛋白基因型分析

目的探讨辽宁省间日疟原虫环子孢子蛋白(CSP)的基因型与地理分布。方法采集镜检确诊的间日疟患者血样15份,Chelex-100离子交换法提取DNA,进行单管-套式PCR扩增,根据琼脂糖凝胶电泳结果判定环子孢子蛋白(CSP)基因型别。结果 12份本地感染间日疟血液标本中6份鉴定为PV-Ⅰ型温带族虫株(占50.00%),6份鉴定为PV-Ⅰ型温带族和PV-Ⅱ型混合虫株(占50.00%);3例输入性间日疟病例中PV-Ⅰ型热带族和温带族各1例,PV-Ⅰ型温带族和PV-Ⅱ型虫株混合感染1例。结论目前辽宁省间日疟原虫存在2种CSP基因型,即PV-Ⅰ型温带族虫株和温带族、PV-Ⅱ型混合感染虫株,无热带族虫株。     

Genetic diversity and multiple infections of Plasmodium vivax malaria in Western Thailand

Using two polymorphic genetic markers, the merozoite surface protein-3alpha (MSP-3alpha) and the circumsporozoite protein (CSP), we investigated the population diversity of Plasmodium vivax in Mae Sod, Thailand from April 2000 through June 2001. Genotyping the parasites isolated from 90 malaria patients attending two local clinics for the dimorphic CSP gene revealed that the majority of the parasites (77%) were the VK210 type. Genotyping the MSP3-alpha gene indicated that P. vivax populations exhibited an equally high level of polymorphism as those from Papua New Guinea, a hyperendemic region. Based on the length of polymerase chain reaction products, three major types of the MSP-3alpha locus were distinguished, with frequencies of 74.8%, 18.7%, and 6.5%, respectively. The 13 alleles distinguished by restriction fragment length polymorphism analysis did not show a significant seasonal variation in frequency. Genotyping the MSP-3alpha and CSP genes showed that 19.3% and 25.6% of the patients had multiple infections, respectively, and the combined rate was 35.6%. Comparisons of MSP-3alpha sequences from nine clones further confirmed the high level of genetic diversity of the parasite and also suggested that geographic isolation may exist. These results strongly indicate that P. vivax populations are highly diverse and multiple clonal infections are common in this malaria-hypoendemic region of Thailand.     

Markers for population genetic analysis of human plasmodia species, P. falciparum and P. vivax

Present report deals with the genetic diversity existing among the field isolates of Plasmodium falciparum and P. vivax in India. Isoenzymes and molecular markers were used to analyse field isolates of P. falciparum and P. vivax. High level of length polymorphism was observed in repeat nucleotide sequences of MSP-1, MSP-2 and GLURP in P. falciparum isolates and CSP, GAM-1 and MSP-3 alpha in P. vivax isolates. In study populations a high proportion of isolates (up to 60%) were comprised of more than one genetically distinct parasite type--multiclonal. Presence of identical allelic forms of enzyme and DNA variations in different geographical areas and in different years suggest that isolates belong to a single random mating population of P. vivax and P. falciparum. Observed random combination of alleles in the field isolates suggest the unlinked nature of loci studied. Study supports the feasibility of using molecular markers for the identification of recrudescence in P. falciparum from fresh infection.     

Influence of HLA-DRB-1 alleles on the production of antibody against CSP, MSP-1, AMA-1, and DBP in Brazilian individuals naturally infected with Plasmodium vivax

We evaluated the influence of allelic frequency of the human leukocyte antigen (HLA) -DRB1 on the acquisition of antibody response against malaria sporozoite and merozoite peptides in patients with Plasmodium vivax malaria acquired in endemic areas of Brazil. IgG antibodies were detected by enzyme-linked immunosorbent assay against four peptides of circumsporozoite protein (CSP) (amino, carboxyl, and VK210 and VK247 repeats) and peptides of merozoite surface protein 1 (MSP-1), apical membrane antigen 1 (AMA-1), and Duffy-binding protein (DBP). We found an association between HLA-DR3 and HLA-DR5 alleles and lack of antibody response to CSP amino terminal, as well as an association between HLA-DR3 and the highest antibody response to MSP1 (Pv200L). In conclusion, we suggest a potential regulatory role of the HLA-DRB1 alleles in the production of antibodies to a conserved region of P. vivax CSP and MSP1 in Brazilian population exposed to malaria.     

Genetic diversity of Plasmodium vivax Pvcsp and Pvmsp1 in Guyana, South America

Approximately 55% of malaria infections in the Guyana Amazon region are attributed to Plasmodium falciparum while the other 45% are attributed to non-falciparum, mostly Plasmodium vivax. However, little is known about the P. vivax strain types circulating in the region. Using PCR for Plasmodium detection and two genetic markers specific to P. vivax to detect the polymorphic circumsporozoite protein (CSP) and the conserved 19-kDa region of the merozoite surface protein-1 (MSP-1), we investigated the overall Plasmodium strain distribution and population diversity within P. vivax in isolates collected from the blood of infected individuals in the interior Amazon region of Guyana, South America. Out of a total of 250 samples positive for Plasmodium, P. vivax was detected in 30% (76/250) and P. falciparum was detected in 76% (189/250). Mixed infections containing both P. falciparum and P. vivax constituted 6% (15/250) of the total positive samples. Further analysis of P. vivax strains showed that 92% (56/61) of the P. vivax samples hybridized with a probe specific to type VK210, 39% (24/61) hybridized with a probe specific for type VK247, and 25% (15/61) hybridized with a probe specific for the P. vivax-like CS genotype. DNA sequencing of the 19-kDa C-terminal domain in block 13 of MSP-1 amplified from 61 samples from patients infected with P. vivax demonstrated that this region is highly conserved, and all samples were identical at the nucleotide level to the Belem and Salvador-1 types. No synonymous or nonsynonymous mutations were observed in this region of the gene, indicating that current vaccine-development efforts based on the MSP-1(19) fragment would be applicable in Guyana.     

Genetic diversity of merozoite surface protein-1 gene of Plasmodium vivax isolates in mining villages of Venezuela (Bolivar State)

The merozoite surface protein-1 gene of Plasmodium vivax is highly polymorphic and so, currently used in epidemiological studies of P. vivax malaria. We sequenced the variable block 5 of the gene from 39 Venezuelan isolates, 18 of which were co-infected with Plasmodium falciparum. We observed a limited variability with 34 isolates belonging to the type Salvador I, none Belem type and only five recombinants. Among the recombinants, only two types of sequences were observed with, respectively, 18 and 21 poly-Q residues. Nucleotide substitutions explained the major differences of the 11 patterns observed. We could evidence neither specific MSP-1 genotype associated with co-infected samples, nor peculiar MSP-1 genotype distribution inside the investigated areas. In comparison with other low endemic regions in the world, our sampling has a lower genetic diversity, which could be mainly explained by the lack of Belem type. In fact, the variable repeats of poly-Q residues involved in the polymorphism of Belem type and recombinant isolates are responsible for a great part of variability observed in MSP-1 block 5.     

High frequency of genetic diversity of Plasmodium vivax field isolates in Myanmar

Malaria is one of the most serious problems threatening human health in Myanmar. Although the morbidity and mortality rates due to malaria have been gradually declining, Myanmar still contributes to a large proportion of malarial death in the South-East Asia region. However, little is known about the nature and extent of genetic diversity of the malarial parasites circulating in Myanmar. In this study, we investigated the overall infection status of Plasmodium and the population diversity of Plasmodium vivax by analyzing three genetic markers, circumsporozoite protein (CSP), merozoite surface protein-1 (MSP-1), and merozoite surface protein-3 (MSP-3α), of P. vivax field isolates collected from infected individuals. In 349 blood samples collected from the individuals who exhibited clinical symptoms associated with malaria, 63.0% showed a positive result for malaria (220/349). P. vivax was detected in 58.2% (128/220) and Plasmodium falciparum was detected in 29.1% (64/220). Mixed infections with both parasites were detected in 12.7% (28/220). The 116 blood samples in which single infection of P. vivax was confirmed were selected and subjected to further genetic analysis. Genotyping of the CSP gene of P. vivax showed that VK210 type (98.3%, 114/116) is predominant in Myanmar, but a significant level of mixed infections of VK210 and VK247 types (24.1%, 28/116) was also identified. Sequence analyses of MSP-1 and MSP-3α genes revealed a large number of distinguishable alleles: 12 for MSP-1 and 25 for MSP-3α. These results collectively suggest that the P. vivax population in Myanmar is highly diverse and multiple clonal infections are prevalent in the country.     

我国间日疟原虫基因型种群结构及其地理分布

目的　用分子技术调查中国间日疟原虫种群结构与地理分布。　方法　用滤纸血滴法采集我国 10个省 (自治区 )间日疟现症病人血样 ,用套式 、半套式 等位特异PCR基因分型法鉴定其型、族归属及其CSP基因型 ,并作流行病学统计分析。　结果　在 384个间日疟原虫分离株中 ,检出温带族 2 5 8株 ,分为 14个不同的(等位变异 )基因型 ,遍布全国各省 ,其中主带≤ 731bp的基因型仅见于南方 5省 ;热带族 79株 ,分为 5个不同基因型 ,分布于北纬 2 5°以南的 5个省 (自治区 ) ;PV 2型 16株 ,包括 2个基因型 ;另 33个分离株为不同型(族 )或不同基因型虫株的重复 (混合 )感染。　结论　目前我国北纬 2 5°以北各省是单一温带族间日疟原虫分布区 ,北纬 2 5°以南地区是温带族与热带族间日疟原虫重叠分布区 ,其中海南和云南两省局部地区同时尚存在PV 2型 ;温带族内存在地理分布明显不同的 2个基因类群。     

辽宁丹东间日疟原虫裂殖子表面蛋白1等位基因型分析

用套式PCR方法扩增辽宁丹东地区间日疟原虫裂殖子表面蛋白1(MSP-1)基因ICB5-ICB6片段,经PvuⅡ酶切和琼脂糖凝胶电泳,对产物进行序列分析。结果显示,11份镜检确诊的间日疟患者血液标本经套式PCR扩增均出现大小约为470 bp(Sal-1型)或400 bp(Belem型)的特异性片段。经PvuⅡ内切酶消化后,其中5份血样(470 bp),出现120和350 bp酶切片段,为Sal-1型;其余6份血样(400 bp)中,1份出现400 bp片段,为Belem型,1份出现120和280 bp两种酶切片段,为重组Ⅲ型,4份出现120和240 bp两种酶切片段,为朝鲜型。辽宁省丹东地区的间日疟原虫PvMSP-1基因存在3种不同的等位基因型,以Sal-1型和朝鲜型为主,但无不同等位基因型的混合感染。