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Sample records for plasmodium nek-2 nima-related

  1. NEK2 serves as a prognostic biomarker for hepatocellular carcinoma.

    PubMed

    Li, Gang; Zhong, Yanping; Shen, Qingrong; Zhou, Yi; Deng, Xiaofang; Li, Cuiping; Chen, Jiagui; Zhou, Ying; He, Min

    2017-02-01

    Never in mitosis gene A (NIMA)-related kinase 2 (NEK2) is a microtubule-associated protein that regulates spindle assembly in human cells and is overexpressed in various malignancies. However, the role of NEK2 in hepatocellular carcinoma (HCC) remains undetermined. We performed RNA-seq of the HCC cell line SMMC-7721 and the normal liver cell line HL-7702 using the Ion Proton System. NEK2 expression was detected using quantitative reverse transcription polymerase chain reaction in two cell lines and 5 matched HCC and adjacent non-tumorous liver tissues. The correlation between survival and NEK2 expression was analyzed in 359 patients with HCC using RNASeqV2 data available from The Cancer Genome Atlas (TCGA) website (https://tcga-data.nci.nih.gov/tcga/). The expression of NEK2, phospho-AKT and MMP-2 was evaluated by immunohistochemistry in 63 cases of HCC and matched adjacent non-tumorous liver tissues. Relationships between protein expression and clinicopathological parameters were assessed, and the correlations between NEK2 with phospho-AKT and MMP-2 expressions were evaluated. A total of 610 differentially expressed genes (DEGs) were revealed in the transcriptome comparison, 297 of which were upregulated and 313 were downregulated in HCC. NEK2, as the most obviously different DEG in cells and tissues from the RNA-seq data, was listed as an HCC candidate biomarker for further verification. NEK2 was overexpressed in HCC cells and tissues (P=0.002, P=0.013) and HCC patients with a high expression of NEK2 had a poor prognosis (P=0.0145). Clinical analysis indicated that the overexpression of NEK2 in HCC was significantly correlated with diolame complete (P<0.001), tumor nodule number (P=0.012) and recurrence (P=0.004). NEK2 expression was positively correlated with the expression of phospho-AKT (r=0.883, P<0.01) and MMP-2 (r=0.781, P<0.01). Overexpression of NEK2 was associated with clinicopathological characteristics and poor patient outcomes, suggesting that NEK2

  2. NEK2 serves as a prognostic biomarker for hepatocellular carcinoma

    PubMed Central

    Li, Gang; Zhong, Yanping; Shen, Qingrong; Zhou, Yi; Deng, Xiaofang; Li, Cuiping; Chen, Jiagui; Zhou, Ying; He, Min

    2017-01-01

    Never in mitosis gene A (NIMA)-related kinase 2 (NEK2) is a microtubule-associated protein that regulates spindle assembly in human cells and is overexpressed in various malignancies. However, the role of NEK2 in hepatocellular carcinoma (HCC) remains undetermined. We performed RNA-seq of the HCC cell line SMMC-7721 and the normal liver cell line HL-7702 using the Ion Proton System. NEK2 expression was detected using quantitative reverse transcription polymerase chain reaction in two cell lines and 5 matched HCC and adjacent non-tumorous liver tissues. The correlation between survival and NEK2 expression was analyzed in 359 patients with HCC using RNASeqV2 data available from The Cancer Genome Atlas (TCGA) website (https://tcga-data.nci.nih.gov/tcga/). The expression of NEK2, phospho-AKT and MMP-2 was evaluated by immunohistochemistry in 63 cases of HCC and matched adjacent non-tumorous liver tissues. Relationships between protein expression and clinicopathological parameters were assessed, and the correlations between NEK2 with phospho-AKT and MMP-2 expressions were evaluated. A total of 610 differentially expressed genes (DEGs) were revealed in the transcriptome comparison, 297 of which were upregulated and 313 were downregulated in HCC. NEK2, as the most obviously different DEG in cells and tissues from the RNA-seq data, was listed as an HCC candidate biomarker for further verification. NEK2 was overexpressed in HCC cells and tissues (P=0.002, P=0.013) and HCC patients with a high expression of NEK2 had a poor prognosis (P=0.0145). Clinical analysis indicated that the overexpression of NEK2 in HCC was significantly correlated with diolame complete (P<0.001), tumor nodule number (P=0.012) and recurrence (P=0.004). NEK2 expression was positively correlated with the expression of phospho-AKT (r=0.883, P<0.01) and MMP-2 (r=0.781, P<0.01). Overexpression of NEK2 was associated with clinicopathological characteristics and poor patient outcomes, suggesting that NEK2

  3. Structure-guided design of purine-based probes for selective Nek2 inhibition

    PubMed Central

    Coxon, Christopher R.; Wong, Christopher; Bayliss, Richard; Boxall, Kathy; Carr, Katherine H.; Fry, Andrew M.; Hardcastle, Ian R.; Matheson, Christopher J.; Newell, David R.; Sivaprakasam, Mangaleswaran; Thomas, Huw; Turner, David; Yeoh, Sharon; Wang, Lan Z.; Golding, Bernard T.; Cano, Céline

    2017-01-01

    Nek2 (NIMA-related kinase 2) is a cell cycle-dependent serine/threonine protein kinase that regulates centrosome separation at the onset of mitosis. Overexpression of Nek2 is common in human cancers and suppression can restrict tumor cell growth and promote apoptosis. Nek2 inhibition with small molecules, therefore, offers the prospect of a new therapy for cancer. To achieve this goal, a better understanding of the requirements for selective-inhibition of Nek2 is required. 6-Alkoxypurines were identified as ATP-competitive inhibitors of Nek2 and CDK2. Comparison with CDK2-inhibitor structures indicated that judicious modification of the 6-alkoxy and 2-arylamino substituents could achieve discrimination between Nek2 and CDK2. In this study, a library of 6-cyclohexylmethoxy-2-arylaminopurines bearing carboxamide, sulfonamide and urea substituents on the 2-arylamino ring was synthesized. Few of these compounds were selective for Nek2 over CDK2, with the best result being obtained for 3-((6-(cyclohexylmethoxy)-9H-purin-2-yl)amino)-N,N-dimethylbenzamide (CDK2 IC50 = 7.0 μM; Nek2 IC50 = 0.62 μM) with >10-fold selectivity. Deletion of the 6-substituent abrogated activity against both Nek2 and CDK2. Nine compounds containing an (E)-dialkylaminovinyl substituent at C-6, all showed selectivity for Nek2, e.g. (E)-6-(2-(azepan-1-yl)vinyl)-N-phenyl-9H-purin-2-amine (CDK2 IC50 = 2.70 μM; Nek2 IC50 = 0.27 μM). Structural biology of selected compounds enabled a partial rationalization of the observed structure activity relationships and mechanism of Nek2 activation. This showed that carboxamide 11 is the first reported inhibitor of Nek2 in the DFG-in conformation. PMID:27833088

  4. Therapeutic Melting Pot of Never in Mitosis Gene A Related Kinase 2 (Nek2): A Perspective on Nek2 as an Oncology Target and Recent Advancements in Nek2 Small Molecule Inhibition

    PubMed Central

    Frett, Brendan; Brown, Robert V.; Ma, Mingliang; Hu, Wenhao; Han, Haiyong; Li, Hong-yu

    2015-01-01

    The global incidence of cancer is on the rise, and within the next decade, the disease is expected to become the leading cause of death worldwide. Forthcoming strategies used to treat cancers focus on the design and implementation of multidrug therapies to target complementary cancer specific pathways. A more direct means by which this multitargeted approach can be achieved is by identifying and targeting interpathway regulatory factors. Recent advances in understanding Nek2 (NIMA related kinase 2) biology suggest that the kinase potentially represents a multifaceted therapeutic target. In this regard, pharmacologic modulation of Nek2 with a single agent may effect several mechanisms important for tumor growth, survival, progression, and metastasis. We herein review the development of Nek2 as an oncology target and provide a succinct chronology of drug discovery campaigns focused on targeting Nek2. PMID:24517277

  5. Targeting NEK2 attenuates glioblastoma growth and radioresistance by destabilizing histone methyltransferase EZH2.

    PubMed

    Wang, Jia; Cheng, Peng; Pavlyukov, Marat S; Yu, Hai; Zhang, Zhuo; Kim, Sung-Hak; Minata, Mutsuko; Mohyeldin, Ahmed; Xie, Wanfu; Chen, Dongquan; Goidts, Violaine; Frett, Brendan; Hu, Wenhao; Li, Hongyu; Shin, Yong Jae; Lee, Yeri; Nam, Do-Hyun; Kornblum, Harley I; Wang, Maode; Nakano, Ichiro

    2017-08-01

    Accumulating evidence suggests that glioma stem cells (GSCs) are important therapeutic targets in glioblastoma (GBM). In this study, we identified NIMA-related kinase 2 (NEK2) as a functional binding protein of enhancer of zeste homolog 2 (EZH2) that plays a critical role in the posttranslational regulation of EZH2 protein in GSCs. NEK2 was among the most differentially expressed kinase-encoding genes in GSC-containing cultures (glioma spheres), and it was required for in vitro clonogenicity, in vivo tumor propagation, and radioresistance. Mechanistically, the formation of a protein complex comprising NEK2 and EZH2 in glioma spheres phosphorylated and then protected EZH2 from ubiquitination-dependent protein degradation in a NEK2 kinase activity-dependent manner. Clinically, NEK2 expression in patients with glioma was closely associated with EZH2 expression and correlated with a poor prognosis. NEK2 expression was also substantially elevated in recurrent tumors after therapeutic failure compared with primary untreated tumors in matched GBM patients. We designed a NEK2 kinase inhibitor, compound 3a (CMP3a), which efficiently attenuated GBM growth in a mouse model and exhibited a synergistic effect with radiotherapy. These data demonstrate a key role for NEK2 in maintaining GSCs in GBM by stabilizing the EZH2 protein and introduce the small-molecule inhibitor CMP3a as a potential therapeutic agent for GBM.

  6. Nek2A/SuFu feedback loop regulates Gli-mediated Hedgehog signaling pathway

    PubMed Central

    Zhou, Fen; Huang, Dengliang; Li, Yong; Hu, Guanghui; Rao, Hai; Lu, Quqin; Luo, Shiwen; Wang, Yao

    2017-01-01

    Suppressor of Fused (SuFu), one of the most conserved components of the Hedgehog (Hh) signaling, binds Gli transcription factors and impedes activation of target gene expression in mammalian cells. Despite the central importance of SuFu in the Hh pathway, little is known about SuFu regulation. In a previous study, we identified NIMA-related expressed kinase 2A (Nek2A) as a SuFu-interacting protein. Here, we show that Nek2A stabilizes SuFu through impairing ubiquitin/proteasome degradation of SuFu. In addition, Nek2A negatively regulates target genes of Hh signaling as well as Gli2 transcriptional activity. In turn, inhibition of Hh signaling by GANT61 diminishes mRNA and protein levels of Nek2A, and Hh agonist promotes transcription of NEK2A gene. Chromatin immunoprecipitation assays revealed that Gli1 and Gli2 directly bind to the promoter regions of NEK2A gene and induced its transcription. Thus, we uncovered one of the mechanisms by which Nek2A acts as a modulator of the Hh signaling pathway in the context of a novel negative-feedback loop, which may offer new insights into Gli-mediated Hh signaling regulation in development and human diseases. PMID:28035348

  7. Clinical significance and prognostic value of Nek2 protein expression in colon cancer.

    PubMed

    Lu, Lei; Zhai, Xiaofeng; Yuan, Ronghua

    2015-01-01

    To determine the expression of NIMA-related kinase NEK2 and evaluate its clinical value in colon cancer. Sixty specimens of colon cancer, 30 specimens of paracancerous colon tissues and 10 specimens of normal colon tissues conventionally resected in surgery at the Second Affiliated Hospital of Nantong University from February 2006 to February 2014 were collected. These tissues were detected for the expression of Nek2 using Western Blot and immunohistochemical staining. The relationship between Nek2 protein expression and the clinicopathology and prognosis of colon tissues was discussed. The expression level and positive expression rate of Nek2 protein in the colon cancer were obviously higher than that in the paracancerous tissues and normal colon tissues. They were also significantly higher in the paracancerous tissues than in the normal tissues (P<0.05). Statistical analysis revealed that Nek2 protein expression was not obviously correlated with gender, age and tumor size, but obviously correlated with degree of differentiation (P=0.008), TNM staging (P=0.000), lymph node metastasis (P=0.022) and tumor invasion (P=0.011). With the plotting of Kaplan-Meier survival curve, it could be seen that Nek2 protein expression was not significantly correlated with survival (P=0.0048). High Nek2 protein expression may be an independent risk factor for colon cancer (HR=0.227, 95% CI 0.101-0.510). High Nek2 protein expression reflects the malignant behavior of colon cancer. Playing important roles in the occurrence of colon cancer, Nek2 protein expression has diagnostic and prognostic value in colon cancer.

  8. Clinical significance and prognostic value of Nek2 protein expression in colon cancer

    PubMed Central

    Lu, Lei; Zhai, Xiaofeng; Yuan, Ronghua

    2015-01-01

    Objective: To determine the expression of NIMA-related kinase NEK2 and evaluate its clinical value in colon cancer. Method: Sixty specimens of colon cancer, 30 specimens of paracancerous colon tissues and 10 specimens of normal colon tissues conventionally resected in surgery at the Second Affiliated Hospital of Nantong University from February 2006 to February 2014 were collected. These tissues were detected for the expression of Nek2 using Western Blot and immunohistochemical staining. The relationship between Nek2 protein expression and the clinicopathology and prognosis of colon tissues was discussed. Results: The expression level and positive expression rate of Nek2 protein in the colon cancer were obviously higher than that in the paracancerous tissues and normal colon tissues. They were also significantly higher in the paracancerous tissues than in the normal tissues (P<0.05). Statistical analysis revealed that Nek2 protein expression was not obviously correlated with gender, age and tumor size, but obviously correlated with degree of differentiation (P=0.008), TNM staging (P=0.000), lymph node metastasis (P=0.022) and tumor invasion (P=0.011). With the plotting of Kaplan-Meier survival curve, it could be seen that Nek2 protein expression was not significantly correlated with survival (P=0.0048). High Nek2 protein expression may be an independent risk factor for colon cancer (HR=0.227, 95% CI 0.101-0.510). Conclusion: High Nek2 protein expression reflects the malignant behavior of colon cancer. Playing important roles in the occurrence of colon cancer, Nek2 protein expression has diagnostic and prognostic value in colon cancer. PMID:26823916

  9. Giardia lamblia Nek1 and Nek2 kinases affect mitosis and excystation.

    PubMed

    Smith, Alias J; Lauwaet, Tineke; Davids, Barbara J; Gillin, Frances D

    2012-04-01

    The NIMA-related serine/threonine kinases (Neks) function in the cell cycle and regulate ciliary and flagellar length. The Giardia lamblia genome encodes 198 Neks, of which 56 are predicted to be active. Here we believe that we report the first functional analysis of two G. lamblia Neks. The GlNek1 and GlNek2 kinase domains share 57% and 43% identity to the kinase domains of human Nek1 and Nek2, respectively. Both GlNeks are active in vitro, have dynamic relocalisation during the cell cycle, and are expressed throughout the life cycle, with GlNek1 being upregulated in cysts. Over-expression of inactive GlNek1 delays disassembly of the parental attachment disc and cytokinesis, whilst over-expression of either wild type GlNek1 or inactive mutant GlNek2 inhibits excystation.

  10. Dishevelled is a NEK2 kinase substrate controlling dynamics of centrosomal linker proteins

    PubMed Central

    Cervenka, Igor; Valnohova, Jana; Bernatik, Ondrej; Harnos, Jakub; Radsetoulal, Matej; Sedova, Katerina; Hanakova, Katerina; Potesil, David; Sedlackova, Miroslava; Salasova, Alena; Steinhart, Zachary; Angers, Stephane; Schulte, Gunnar; Hampl, Ales; Zdrahal, Zbynek; Bryja, Vitezslav

    2016-01-01

    Dishevelled (DVL) is a key scaffolding protein and a branching point in Wnt signaling pathways. Here, we present conclusive evidence that DVL regulates the centrosomal cycle. We demonstrate that DVL dishevelled and axin (DIX) domain, but not DIX domain-mediated multimerization, is essential for DVL’s centrosomal localization. DVL accumulates during the cell cycle and associates with NIMA-related kinase 2 (NEK2), which is able to phosphorylate DVL at a multitude of residues, as detected by a set of novel phospho-specific antibodies. This creates interfaces for efficient binding to CDK5 regulatory subunit-associated protein 2 (CDK5RAP2) and centrosomal Nek2-associated protein 1 (C-NAP1), two proteins of the centrosomal linker. Displacement of DVL from the centrosome and its release into the cytoplasm on NEK2 phosphorylation is coupled to the removal of linker proteins, an event necessary for centrosomal separation and proper formation of the mitotic spindle. Lack of DVL prevents NEK2-controlled dissolution of loose centrosomal linker and subsequent centrosomal separation. Increased DVL levels, in contrast, sequester centrosomal NEK2 and mimic monopolar spindle defects induced by a dominant negative version of this kinase. Our study thus uncovers molecular crosstalk between centrosome and Wnt signaling. PMID:27486244

  11. Nek2 siRNA therapy using a portal venous port-catheter system for liver metastasis in pancreatic cancer.

    PubMed

    Kokuryo, Toshio; Hibino, Shigeru; Suzuki, Kazushi; Watanabe, Katsutaka; Yokoyama, Yukihiro; Nagino, Masato; Senga, Takeshi; Hamaguchi, Michinari

    2016-09-01

    Nek2 (NIMA-related kinase 2) is a serine-threonine kinase and human homolog of the mitotic regulator NIMA of Aspergillus nidulan. We reported the efficiency of Nek2 siRNA in several cancer xenograft models using cholangiocarcinoma, breast cancer and colorectal cancer. Pancreatic cancer is difficult to treat due to its rapid progression and resistance to chemotherapy. Novel treatments are urgently required to improve survival in pancreatic cancer, and siRNA are a promising therapeutic option. However, finding an in vivo drug delivery system of siRNA remains a major problem for clinical application. In this study, the overexpression of Nek2 was identified in pancreatic cancer cell lines. Nek2 siRNA inhibited tumor growth in a subcutaneous xenograft mouse model of pancreatic cancer, prolonged the survival time in an intraperitoneal xenograft mouse model and efficiently prevented the progression of liver metastasis using a portal venous port-catheter system. Taken together, Nek2 is an effective therapeutic target in pancreatic cancer. An adequate delivery system is considered important in treating advanced pancreatic cancer, such as peritoneal dissemination and liver metastasis. Further investigations are required on the safety and side effects of the portal venous port-catheter system. We hope that Nek2 siRNA will be a novel therapeutic strategy for pancreatic cancer with liver metastasis and peritoneal dissemination.

  12. Cep68 can be regulated by Nek2 and SCF complex.

    PubMed

    Man, Xiaohui; Megraw, Timothy L; Lim, Yoon Pin

    2015-01-01

    Centrosome cohesion maintains centrosomes in close proximity until mitosis, when cell cycle-dependent regulatory signaling events dissolve cohesion and promote centrosome separation in preparation for bipolar spindle assembly at mitosis. Cohesion is regulated by the antagonistic activities of the mitotic NIMA-related kinase 2 (Nek2), protein phosphatase 1, the cohesion fiber components rootletin, centrosomal Nek2-associated protein 1 (C-Nap1) and Cep68. The centrosomal protein Cep68 is essential for centrosome cohesion and dissociates from centrosomes at the onset of mitosis. Here, our cell line studies show the C-terminal 300-400 amino acids of Cep68 are necessary to localize Cep68 to interphase centrosomes while C-terminal 400-500 amino acids might regulate Cep68 dissociation from centrosomes at mitotic onset. In addition, Nek2 was demonstrated to phosphorylate Cep68 in vivo and this phosphorylation appears to promote Cep68 degradation in mitosis. We further show that the SCF complex destroys Cep68 at mitosis through recognition by the beta-Trcp F box component of SCF. Together, the findings provide a new insight into the control of centrosome separation by Cep68 during mitosis. Copyright © 2015 Elsevier GmbH. All rights reserved.

  13. Irreversible Nek2 kinase inhibitors with cellular activity

    PubMed Central

    Henise, Jeffrey C.; Taunton, Jack

    2013-01-01

    A structure-based approach was used to design irreversible, cysteine-targeted inhibitors of the human centrosomal kinase, Nek2. Potent inhibition of Nek2 kinase activity in biochemical and cell-based assays required a noncatalytic cysteine residue (Cys22), located near the glycine-rich loop in a subset of human kinases. Elaboration of an oxindole scaffold led to our most selective compound, oxindole propynamide 16 (JH295). Propynamide 16 irreversibly inhibited cellular Nek2 without affecting the mitotic kinases, Cdk1, Aurora B, or Plk1. Moreover, 16 did not perturb bipolar spindle assembly or the spindle assembly checkpoint. To our knowledge, 16 is the first small molecule shown to inactivate Nek2 kinase activity in cells. PMID:21627121

  14. Discovery of potent NEK2 inhibitors as potential anticancer agents using structure-based exploration of NEK2 pharmacophoric space coupled with QSAR analyses.

    PubMed

    Khanfar, Mohammad A; Banat, Fahmy; Alabed, Shada; Alqtaishat, Saja

    2017-02-01

    High expression of Nek2 has been detected in several types of cancer and it represents a novel target for human cancer. In the current study, structure-based pharmacophore modeling combined with multiple linear regression (MLR)-based QSAR analyses was applied to disclose the structural requirements for NEK2 inhibition. Generated pharmacophoric models were initially validated with receiver operating characteristic (ROC) curve, and optimum models were subsequently implemented in QSAR modeling with other physiochemical descriptors. QSAR-selected models were implied as 3D search filters to mine the National Cancer Institute (NCI) database for novel NEK2 inhibitors, whereas the associated QSAR model prioritized the bioactivities of captured hits for in vitro evaluation. Experimental validation identified several potent NEK2 inhibitors of novel structural scaffolds. The most potent captured hit exhibited an [Formula: see text] value of 237 nM.

  15. Preclinical activity of MBM-5 in gastrointestinal cancer by inhibiting NEK2 kinase activity

    PubMed Central

    Zhu, Mengli; Zhu, Tong; Jiang, Tongtong; Frett, Brendan; Hu, Wenhao; Li, Hong-yu; Ma, Mingliang; Zhang, Xiongwen

    2016-01-01

    NEK2 is a conserved mitotic regulator critical for cell cycle progression. Aberrant expression of NEK2 has been found in a variety of human cancers, making it an attractive molecular target for the design of novel anticancer therapeutics. In the present study, we have identified a novel compound MBM-5, which was found to bind to NEK2 with high affinity by docking simulations study. MBM-5 potently inhibited NEK2 kinase activity in vitro in a concentration-dependent manner. MBM-5 also suppressed cellular NEK2 kinase activity, as evidenced by the decreased phosphorylation of its substrate Hec1 on S165 in a concentration- and time-dependent manner. This inhibition impeded mitotic progression by inducing chromosome segregation defects and cytokinesis failure; therefore leading to accumulation of cells with ≥4N DNA content, which finally underwent apoptosis. More importantly, MBM-5 treatment effectively suppressed the tumor growth of human gastric and colorectal cancer cells xenografts. Taken together, we demonstrated that MBM-5 effectively inhibited the kinase activity of NEK2 and showed a potential application in anti-cancer treatment regimens. PMID:27764815

  16. Nek2 activation of Kif24 ensures cilium disassembly during the cell cycle

    PubMed Central

    Kim, Sehyun; Lee, Kwanwoo; Choi, Jung-Hwan; Ringstad, Niels; Dynlacht, Brian David

    2015-01-01

    Many proteins are known to promote ciliogenesis, but mechanisms that promote primary cilia disassembly before mitosis are largely unknown. Here we identify a mechanism that favours cilium disassembly and maintains the disassembled state. We show that co-localization of the S/G2 phase kinase, Nek2 and Kif24 triggers Kif24 phosphorylation, inhibiting cilia formation. We show that Kif24, a microtubule depolymerizing kinesin, is phosphorylated by Nek2, which stimulates its activity and prevents the outgrowth of cilia in proliferating cells, independent of Aurora A and HDAC6. Our data also suggest that cilium assembly and disassembly are in dynamic equilibrium, but Nek2 and Kif24 can shift the balance toward disassembly. Further, Nek2 and Kif24 are overexpressed in breast cancer cells, and ablation of these proteins restores ciliation in these cells, thereby reducing proliferation. Thus, Kif24 is a physiological substrate of Nek2, which regulates cilia disassembly through a concerted mechanism involving Kif24-mediated microtubule depolymerization. PMID:26290419

  17. Effect of NIMA-related kinase 2B on the sensitivity of breast cancer to paclitaxel in vitro and vivo.

    PubMed

    Wang, Yahong; Shen, Honghong; Yin, Quangui; Zhang, Tongxian; Liu, Ziyu; Zhang, Wei; Niu, Yun

    2017-05-01

    NIMA-related kinase 2B has been known to be an important centrosome regulatory factor. The aim of this study was to investigate the effect of NIMA-related kinase 2B on the sensitivity of breast cancer to paclitaxel. We detected the expression of NIMA-related kinase 2B messenger RNA in MCF-10 cells, including MCF-10A, MCF-10AT, MCF-10DCIS.com , and MCF-10CA1a. The influence of NIMA-related kinase 2B in nude mouse was also detected. The association between NIMA-related kinase 2B and clinicopathological factors was explored in invasive ductal carcinoma tissues. NIMA-related kinase 2B was lowly expressed in the precancerous cells, MCF-10A and MCF-10AT, and it was highly expressed in carcinomatous cells, MCF-10DCIS.com and MCF-10CA1a. The upregulation of NIMA-related kinase 2B can introduce the growth of MCF-10AT cells, knockdown of NIMA-related kinase 2B could remarkably inhibit cell proliferation in MCF-10DCIS.com and MCF-10 CA1a cells. Comparing the volume of the xenografts in nude mouse, we found that the tumors treated by NIMA-related kinase 2B small interfering RNA associated with paclitaxel were the smallest among all the groups. Expression of NIMA-related kinase 2B messenger RNA was associated with higher histological grades, positive lymph node, and high Ki67 index (>20%). The partial response rates were 75.0% in NIMA-related kinase 2B negative (NIMA-related kinase 2B-) patients and 15.8% in NIMA-related kinase 2B++ patients. The progressive disease rates were 10.0% in NIMA-related kinase 2B- patients and 52.6% in NIMA-related kinase 2B++ patients ( p = 0.002). Our findings suggested that NIMA-related kinase 2B could play a role in the development and progression of breast cancer. Combination treatment using NIMA-related kinase 2B small interfering RNA and paclitaxel might be a novel potential therapy method for breast cancer.

  18. Characterization of Cep85 – a new antagonist of Nek2A that is involved in the regulation of centrosome disjunction

    PubMed Central

    Chen, Canhe; Tian, Fang; Lu, Lin; Wang, Yun; Xiao, Zhe; Yu, Chengtao; Yu, Xianwen

    2015-01-01

    ABSTRACT Nek2 has been implicated in centrosome disjunction at the onset of mitosis to promote bipolar spindle formation, and hyperactivation of Nek2 leads to the premature centrosome separation. Its activity, therefore, needs to be strictly regulated. In this study, we report that Cep85, an uncharacterized centrosomal protein, acts as a binding partner of Nek2A. It colocalizes with isoform A of Nek2 (Nek2A) at centrosomes and forms a granule meshwork enveloping the proximal ends of centrioles. Opposite to the effects of Nek2A, overexpression of Cep85 in conjunction with inhibition of the motor protein Eg5 (also known as KIF11) leads to the failure of centrosome disjunction. By contrast, depletion of Cep85 results in the precocious centrosome separation. We also define the Nek2A binding and centrosome localization domains within Cep85. Although the Nek2A-binding domain alone is sufficient to inhibit Nek2A kinase activity in vitro, both domains are indispensable for full suppression of centrosome disjunction in cells. Thus, we propose that Cep85 is a bona fide Nek2A-binding partner that surrounds the proximal ends of centrioles where it cooperates with PP1γ (also known as PPP1CC) to antagonize Nek2A activity in order to maintain the centrosome integrity in interphase in mammalian cells. PMID:26220856

  19. NIMA-related kinase NEK6 affects plant growth and stress response in Arabidopsis.

    PubMed

    Zhang, Bo; Chen, Hao-Wei; Mu, Rui-Ling; Zhang, Wang-Ke; Zhao, Ming-Yu; Wei, Wei; Wang, Fang; Yu, Hui; Lei, Gang; Zou, Hong-Feng; Ma, Biao; Chen, Shou-Yi; Zhang, Jin-Song

    2011-12-01

    The NIMA-related kinases (NEKs) are a family of serine/threonine kinases involved largely in cell cycle control in fungi, mammals and other eukaryotes. In Arabidopsis, NEK6 is involved in the regulation of epidermal cell morphogenesis. However, other roles of NEK6 in plants are less well understood. Here we report functions of NEK6 in plant growth, development and stress responses in Arabidopsis. NEK6 transcripts and proteins are induced by ethylene precursor ACC and salt stress. Expression of other NEK genes except NEK5 is also responsive to the two treatments. Overexpression and mutant analysis disclose that the NEK6 gene increases rosette growth, seed yield and lateral root formation. However, NEK6 appears to play a negative role in the control of seed size. The gene also promotes plant tolerance to salt stress and osmotic stress in its overexpressing plants. The NEK6 gene may achieve its function through suppression of ethylene biosynthesis and activation of CYCB1;1 and CYCA3;1 expression. Our present study reveals new functions of the NEK6 gene in plant growth and stress tolerance, and manipulation of NEK6 may improve important agronomic traits in crop plants.

  20. Small molecule targeting the Hec1/Nek2 mitotic pathway suppresses tumor cell growth in culture and in animal

    PubMed Central

    Wu, Guikai; Qiu, Xiao-Long; Zhou, Longen; Zhu, Jiewen; Chamberlin, Richard; Lau, Johnson; Chen, Phang-Lang; Lee, Wen-Hwa

    2009-01-01

    Hec1 is a conserved mitotic regulator critical for spindle checkpoint control, kinetochore functionality and cell survival. Overexpression of Hec1 has been detected in a variety of human cancers and is linked to poor prognosis of primary breast cancers. Through a chemical genetic screening, we have identified a small molecule, INH1, which specifically disrupts the Hec1/Nek2 interaction via direct Hec1 binding. Treating cells with INH1 triggered reduction of kinetochore-bound Hec1 as well as global Nek2 protein level, consequently leading to metaphase chromosome misalignment, spindle aberrancy and eventual cell death. INH1 effectively inhibited the proliferation of multiple human breast cancer cell lines in culture (GI50 10~21 μM). Furthermore, treatment with INH1 retarded tumor growth in a nude mouse model bearing xenografts derived from the human breast cancer line MDA-MB-468, with no apparent side effects. This study suggests that the Hec1/Nek2 pathway may serve as a novel mitotic target for cancer intervention by small compounds. PMID:18922912

  1. The involvement of Nek2 and Notch in the proliferation of rat adrenal cortex triggered by POMC-derived peptides.

    PubMed

    de Mendonca, Pedro Omori Ribeiro; Costa, Ismael Cabral; Lotfi, Claudimara Ferini Pacicco

    2014-01-01

    The adrenal gland is a dynamic organ that undergoes constant cell turnover. This allows for rapid organ remodeling in response to the physiological demands of the HPA axis, which is controlled by proopiomelanocortin (POMC)-derived peptides, such as adrenocorticotropic hormone (ACTH) and N-Terminal peptides (N-POMC). In the rat adrenal cortex, POMC-derived peptides trigger a mitogenic effect, and this process increases cyclins D and E, while inhibiting p27Kip1. The goal of the present study was to further explore the mitogenic effect of ACTH and synthetic N-POMC1-28 peptides by investigating the differences in the expression of key genes involved in the cell cycle of the rat adrenal cortex, following inhibition of the HPA axis. Moreover, we evaluated the differences between the inner and outer fractions of the adrenal cortex (ZF-fraction and ZG-fraction) in terms of their response patterns to different stimuli. In the current study, the inhibition of the HPA axis repressed the expression of Ccnb2, Camk2a, and Nek2 genes throughout the adrenal cortex, while treatments with POMC-derived peptides stimulated Nek2, gene and protein expression, and Notch2 gene expression. Furthermore, Notch1 protein expression was restricted to the subcapsular region of the cortex, an area of the adrenal cortex that is well-known for proliferation. We also showed that different regions of the adrenal cortex respond to HPA-axis inhibition and to induction with POMC-derived peptides at different times. These results suggest that cells in the ZG and ZF fractions could be at different phases of the cell cycle. Our results contribute to the understanding of the mechanisms involved in cell cycle regulation in adrenocortical cells triggered by N-POMC peptides and ACTH, and highlight the involvement of genes such as Nek2 and Notch.

  2. Structure, function, and evolution of plant NIMA-related kinases: implication for phosphorylation-dependent microtubule regulation.

    PubMed

    Takatani, Shogo; Otani, Kento; Kanazawa, Mai; Takahashi, Taku; Motose, Hiroyasu

    2015-11-01

    Microtubules are highly dynamic structures that control the spatiotemporal pattern of cell growth and division. Microtubule dynamics are regulated by reversible protein phosphorylation involving both protein kinases and phosphatases. Never in mitosis A (NIMA)-related kinases (NEKs) are a family of serine/threonine kinases that regulate microtubule-related mitotic events in fungi and animal cells (e.g. centrosome separation and spindle formation). Although plants contain multiple members of the NEK family, their functions remain elusive. Recent studies revealed that NEK6 of Arabidopsis thaliana regulates cell expansion and morphogenesis through β-tubulin phosphorylation and microtubule destabilization. In addition, plant NEK members participate in organ development and stress responses. The present phylogenetic analysis indicates that plant NEK genes are diverged from a single NEK6-like gene, which may share a common ancestor with other kinases involved in the control of microtubule organization. On the contrary, another mitotic kinase, polo-like kinase, might have been lost during the evolution of land plants. We propose that plant NEK members have acquired novel functions to regulate cell growth, microtubule organization, and stress responses.

  3. NIMA-related kinases regulate directional cell growth and organ development through microtubule function in Arabidopsis thaliana.

    PubMed

    Motose, Hiroyasu; Takatani, Shogo; Ikeda, Tatsuya; Takahashi, Taku

    2012-12-01

    NIMA-related kinase 6 (NEK6) regulates cellular expansion and morphogenesis through microtubule organizaiton in Arabidopsis thaliana. Loss-of-function mutations in NEK6 (nek6/ibo1) cause ectopic outgrowth and microtubule disorganization in epidermal cells. We recently found that NEK6 forms homodimers and heterodimers with NEK4 and NEK5 to destabilize cortical microtubules possibly by direct binding to microtubules and the β-tubulin phosphorylation. Here, we identified a new allele of NEK6 and further analyzed the morphological phenotypes of nek6/ibo1 mutants, along with alleles of nek4 and nek5 mutants. Phenotypic analysis demonstrated that NEK6 is required for the directional growth of roots and hypocotyls, petiole elongation, cell file formation, and trichome morphogenesis. In addition, nek4, nek5, and nek6/ibo1 mutants were hypersensitive to microtubule inhibitors such as propyzamide and taxol. These results suggest that plant NEKs function in directional cell growth and organ development through the regulation of microtubule organization.

  4. Inhibition of never in mitosis A (NIMA)-related kinase-4 reduces survivin expression and sensitizes cancer cells to TRAIL-induced cell death.

    PubMed

    Park, So Jung; Jo, Doo Sin; Jo, Se-Young; Shin, Dong Woon; Shim, Sangmi; Jo, Yoon Kyung; Shin, Ji Hyun; Ha, Ye Jin; Jeong, Seong-Yun; Hwang, Jung Jin; Kim, Young Sam; Suh, Young-Ah; Chang, Jong Wook; Kim, Jin Cheon; Cho, Dong-Hyung

    2016-10-04

    The tumor necrosis factor-related apoptosis inducing ligand (TRAIL) preferentially induces apoptosis in cancer cells. However, many tumors are resistant to TRAIL-induced apoptosis, and resistance mechanisms are not fully understood. To identify novel regulatory molecules of TRAIL resistance, we screened a siRNA library targeting the human kinome, and NEK4 (NIMA-related kinase-4) was identified. Knockdown of NEK4 sensitized TRAIL-resistant cancer cells and in vivo xenografts to cell death. In contrast, over expression of NEK4 suppressed TRAIL-induced cell death in TRAIL-sensitive cancer cells. In addition, loss of NEK4 resulted in decrease of the anti-apoptotic protein survivin, but an increase in apoptotic cell death. Interestingly, NEK4 was highly upregulated in tumor tissues derived from patients with lung cancer and colon cancer. These results suggest that inhibition of NEK4 sensitizes cancer cells to TRAIL-induced apoptosis by regulation of survivin expression.

  5. Inhibition of never in mitosis A (NIMA)-related kinase-4 reduces survivin expression and sensitizes cancer cells to TRAIL-induced cell death

    PubMed Central

    Park, So Jung; Jo, Doo Sin; Jo, Se-Young; Shin, Dong Woon; Shim, Sangmi; Jo, Yoon Kyung; Shin, Ji Hyun; Ha, Ye Jin; Jeong, Seong-Yun; Hwang, Jung Jin; Kim, Young Sam; Suh, Young-Ah; Chang, Jong Wook; Kim, Jin Cheon; Cho, Dong-Hyung

    2016-01-01

    The tumor necrosis factor-related apoptosis inducing ligand (TRAIL) preferentially induces apoptosis in cancer cells. However, many tumors are resistant to TRAIL-induced apoptosis, and resistance mechanisms are not fully understood. To identify novel regulatory molecules of TRAIL resistance, we screened a siRNA library targeting the human kinome, and NEK4 (NIMA-related kinase-4) was identified. Knockdown of NEK4 sensitized TRAIL-resistant cancer cells and in vivo xenografts to cell death. In contrast, over expression of NEK4 suppressed TRAIL-induced cell death in TRAIL-sensitive cancer cells. In addition, loss of NEK4 resulted in decrease of the anti-apoptotic protein survivin, but an increase in apoptotic cell death. Interestingly, NEK4 was highly upregulated in tumor tissues derived from patients with lung cancer and colon cancer. These results suggest that inhibition of NEK4 sensitizes cancer cells to TRAIL-induced apoptosis by regulation of survivin expression. PMID:27602754

  6. The ARM Domain of ARMADILLO-REPEAT KINESIN 1 is Not Required for Microtubule Catastrophe But Can Negatively Regulate NIMA-RELATED KINASE 6 in Arabidopsis thaliana.

    PubMed

    Eng, Ryan C; Halat, Laryssa S; Livingston, Samuel J; Sakai, Tatsuya; Motose, Hiroyasu; Wasteneys, Geoffrey O

    2017-08-01

    Microtubules are dynamic filaments, the assembly and disassembly of which are under precise control of various associated proteins, including motor proteins and regulatory enzymes. In Arabidopsis thaliana, two such proteins are the ARMADILLO-REPEAT KINESIN 1 (ARK1), which promotes microtubule disassembly, and the NIMA-RELATED KINASE 6 (NEK6), which has a role in organizing microtubule arrays. Previous yeast two-hybrid and in vitro pull-down assays determined that NEK6 can interact with ARK1 through the latter protein's Armadillo-repeat (ARM) cargo domain. To explore the function of the ARM domain, we generated fluorescent reporter fusion proteins to ARK1 lacking the ARM domain (ARK1ΔARM-GFP) and to the ARM domain alone (ARM-GFP). Both of these constructs strongly associated with the growing plus ends of microtubules, but only ARK1ΔARM-GFP was capable of inducing microtubule catastrophe and rescuing the ark1-1 root hair phenotype. These results indicate that neither the ARM domain nor NEK6's putative interaction with it is required for ARK1 to induce microtubule catastrophe. In further exploration of the ARK1-NEK6 relationship, we demonstrated that, despite evidence that NEK6 can phosphorylate ARK1 in vitro, the in vivo distribution and function of ARK1 were not affected by the loss of NEK6, and vice versa. Moreover, NEK6 and ARK1 were found to have overlapping but non-identical distribution on microtubules, and hormone treatments known to affect NEK6 activity did not stimulate interaction. These findings suggest that ARK1 and NEK6 function independently in microtubule dynamics and cell morphogenesis. Despite the results of this functional analysis, we found that overexpression of the ARM domain led to complete loss of NEK6 transcription, suggesting that the ARM domain might have a regulatory role in NEK6 expression. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions

  7. Plasmodium immunomics.

    PubMed

    Doolan, Denise L

    2011-01-01

    The Plasmodium parasite, the causative agent of malaria, is an excellent model for immunomic-based approaches to vaccine development. The Plasmodium parasite has a complex life cycle with multiple stages and stage-specific expression of ∼5300 putative proteins. No malaria vaccine has yet been licensed. Many believe that an effective vaccine will need to target several antigens and multiple stages, and will require the generation of both antibody and cellular immune responses. Vaccine efforts to date have been stage-specific and based on only a very limited number of proteins representing <0.5% of the genome. The recent availability of comprehensive genomic, proteomic and transcriptomic datasets from human and selected non-human primate and rodent malarias provide a foundation to exploit for vaccine development. This information can be mined to identify promising vaccine candidate antigens, by proteome-wide screening of antibody and T cell reactivity using specimens from individuals exposed to malaria and technology platforms such as protein arrays, high throughput protein production and epitope prediction algorithms. Such antigens could be incorporated into a rational vaccine development process that targets specific stages of the Plasmodium parasite life cycle with immune responses implicated in parasite elimination and control. Immunomic approaches which enable the selection of the best possible targets by prioritising antigens according to clinically relevant criteria may overcome the problem of poorly immunogenic, poorly protective vaccines that has plagued malaria vaccine developers for the past 25 years. Herein, current progress and perspectives regarding Plasmodium immunomics are reviewed.

  8. Plasmodium Immunomics

    PubMed Central

    Doolan, Denise L.

    2010-01-01

    The Plasmodium parasite, the causative agent of malaria, is an excellent model for immunomic-based approaches to vaccine development. The Plasmodium parasite has a complex life cycle with multiple stages and stage-specific expression of ~ 5,300 putative proteins. No malaria vaccine has yet been licensed. Many believe that an effective vaccine will need to target several antigens and multiple stages, and will require the generation of both antibody and cellular immune responses. Vaccine efforts to date have been stage-specific and based on only a very limited number of proteins representing < 0.5% of the genome. The recent availability of comprehensive genomic, proteomic and transcriptomic datasets from human and selected non-human primate and rodent malarias provide a foundation to exploit for vaccine development. This information can be mined to identify promising vaccine candidate antigens, by proteome-wide screening of antibody and T cell reactivity using specimens from individuals exposed to malaria and technology platforms such as protein arrays, high throughput protein production and epitope prediction algorithms. Such antigens could be incorporated into a rational vaccine development process that targets specific stages of the Plasmodium parasite life cycle with immune responses implicated in parasite elimination and control. Immunomic approaches which enable the selection of the best possible targets by prioritizing antigens according to clinically relevant criteria may overcome the problem of poorly immunogenic, poorly protective vaccines that has plagued malaria vaccine developers for the past 25 years. Herein, current progress and perspectives regarding Plasmodium immunomics are reviewed. PMID:20816843

  9. A Malaria Transmission-Blocking (+)-Usnic Acid Derivative Prevents Plasmodium Zygote-to-Ookinete Maturation in the Mosquito Midgut.

    PubMed

    Pastrana-Mena, Rebecca; Mathias, Derrick K; Delves, Michael; Rajaram, Krithika; King, Jonas G; Yee, Rebecca; Trucchi, Beatrice; Verotta, Luisella; Dinglasan, Rhoel R

    2016-12-16

    The evolution of drug resistance is a recurrent problem that has plagued efforts to treat and control malaria. Recent emergence of artemisinin resistance in Southeast Asia underscores the need to develop novel antimalarials and identify new targetable pathways in Plasmodium parasites. Transmission-blocking approaches, which typically target gametocytes in the host bloodstream or parasite stages in the mosquito gut, are recognized collectively as a strategy that when used in combination with antimalarials that target erythrocytic stages will not only cure malaria but will also prevent subsequent transmission. We tested four derivatives of (+)-usnic acid, a metabolite isolated from lichens, for transmission-blocking activity against Plasmodium falciparum using the standard membrane feeding assay. For two of the derivatives, BT37 and BT122, we observed a consistent dose-response relationship between concentration in the blood meal and oocyst intensity in the midgut. To explore their mechanism of action, we used the murine model Plasmodium berghei and found that both derivatives prevent ookinete maturation. Using fluorescence microscopy, we demonstrated that in the presence of each compound zygote vitality was severely affected, and those that did survive failed to elongate and mature into ookinetes. The observed phenotypes were similar to those described for mutants of specific kinases (NEK2/NEK4) and of inner membrane complex 1 (IMC1) proteins, which are all vital to the zygote-to-ookinete transition. We discuss the implications of our findings and our high-throughput screening approach to identifying next generation, transmission-blocking antimalarials based on the scaffolds of these (+)-usnic acid derivatives.

  10. Manipulating the Plasmodium genome.

    PubMed

    Carvalho, Teresa Gil; Ménard, Robert

    2005-01-01

    Genome manipulation, the primary tool for assigning function to sequence, will be essential for understanding Plasmodium biology and malaria pathogenesis in molecular terms. The first success in transfecting Plasmodium was reported almost ten years ago. Gene-targeting studies have since flourished, as Plasmodium is haploid and integrates DNA only by homologous recombination. These studies have shed new light on the function of many proteins, including vaccine candidates and drug resistance factors. However, many essential proteins, including those involved in parasite invasion of erythrocytes, cannot be characterized in the absence of conditional mutagenesis. Proteins also cannot be identified on a functional basis as random DNA integration has not been achieved. We overview here the ways in which the Plasmodium genome can be manipulated. We also point to the tools that should be established if our goal is to address parasite infectivity in a systematic way and to conduct refined structure-function analysis of selected products.

  11. Secretory transport in Plasmodium.

    PubMed

    Elmendorf, H G; Haldar, K

    1993-03-01

    The asexual blood stage of the human malaria parasite Plasmodium falciparum resides within the mature erythrocyte - a cell that has no intracellular organelles and few biosynthetic activities. However, Plasmodium, as on actively growing and dividing cell, has numerous requirements for the uptake o f nutrients and expulsion of waste. Hence, the parasite must extensively remodel the erythrocyte to facilitate its survival, not only by exporting numerous proteins, but also by providing the requisite machinery for their .trafficking. In this review, Heidi Elmendorf and Kastun Haldar propose a model for secretion in P. falciparum.

  12. Plasmodium and mononuclear phagocytes.

    PubMed

    Mac-Daniel, Laura; Ménard, Robert

    2015-01-01

    Plasmodium, the causative agent of malaria, initially multiplies inside liver cells and then in successive cycles inside erythrocytes, causing the symptoms of the disease. In this review, we discuss interactions between the extracellular and intracellular forms of the Plasmodium parasite and innate immune cells in the mammalian host, with a special emphasis on mononuclear phagocytes. We overview here what is known about the innate immune cells that interact with parasites, mechanisms used by the parasite to evade them, and the protective or detrimental contribution of these interactions on parasite progression through its life cycle and pathology in the host.

  13. Plasmodium falciparum malaria.

    PubMed

    Shetty, A K; Steele, R W

    1999-01-01

    A 13-year-old adolescent daughter of a missionary presented with fever and jaundice 1 week after returning from Africa. Examination of peripheral blood film revealed the diagnosis of Plasmodium falciparum infection. Therapy with oral quinine and doxycycline was curative. Diagnosis requires a travel history and a high index of suspicion. Because of the frequency of international travel, United States physicians need to be familiar with the presentation and management of imported P falciparum. Preparation for such travel must include careful counseling and optimal use of chemoprophylaxis.

  14. Attacking Plasmodium vivax

    PubMed Central

    Baird, J. Kevin

    2016-01-01

    Discussions beginning in 2012 ultimately led to a landmark document from the World Health Organization (WHO) titled, Control and Elimination of Plasmodium vivax: A Technical Brief, published in July 2015. That body of work represents multiple expert consultations coordinated by the WHO Global Malaria Program, along with technical consensus gathering from national malaria control programs via the WHO regional offices around the globe. That document thus represents thoroughly vetted state-of-the-art recommendations for dealing specifically with P. vivax, the first assembly of such by the WHO. This supplement to the journal was commissioned by the WHO and compiles the very substantial body of evidence and analysis informing those recommendations. This introductory narrative to the supplement provides the historical and technological context of global strategy for combatting P. vivax and reducing the burdens of morbidity and mortality it imposes. PMID:27708186

  15. Diagnosis and Treatment of Plasmodium vivax Malaria

    PubMed Central

    Baird, J. Kevin; Valecha, Neena; Duparc, Stephan; White, Nicholas J.; Price, Ric N.

    2016-01-01

    The diagnosis and treatment of Plasmodium vivax malaria differs from that of Plasmodium falciparum malaria in fundamentally important ways. This article reviews the guiding principles, practices, and evidence underpinning the diagnosis and treatment of P. vivax malaria. PMID:27708191

  16. Plasmodium vivax: who cares?

    PubMed Central

    Galinski, Mary R; Barnwell, John W

    2008-01-01

    More attention is being focused on malaria today than any time since the world's last efforts to achieve eradication over 40 years ago. The global community is now discussing strategies aimed at dramatically reducing malarial disease burden and the eventual eradication of all types of malaria, everywhere. As a consequence, Plasmodium vivax, which has long been neglected and mistakenly considered inconsequential, is now entering into the strategic debates taking place on malaria epidemiology and control, drug resistance, pathogenesis and vaccines. Thus, contrary to the past, the malaria research community is becoming more aware and concerned about the widespread spectrum of illness and death caused by up to a couple of hundred million cases of vivax malaria each year. This review brings these issues to light and provides an overview of P. vivax vaccine development, then and now. Progress had been slow, given inherent research challenges and minimal support in the past, but prospects are looking better for making headway in the next few years. P. vivax, known to invade the youngest red blood cells, the reticulocytes, presents a strong challenge towards developing a reliable long-term culture system to facilitate needed research. The P. vivax genome was published recently, and vivax researchers now need to coordinate efforts to discover new vaccine candidates, establish new vaccine approaches, capitalize on non-human primate models for testing, and investigate the unique biological features of P. vivax, including the elusive P. vivax hypnozoites. Comparative studies on both P. falciparum and P. vivax in many areas of research will be essential to eradicate malaria. And to this end, the education and training of future generations of dedicated "malariologists" to advance our knowledge, understanding and the development of new interventions against each of the malaria species infecting humans also will be essential. PMID:19091043

  17. Plasmodium vivax Malaria in Cambodia

    PubMed Central

    Siv, Sovannaroth; Roca-Feltrer, Arantxa; Vinjamuri, Seshu Babu; Bouth, Denis Mey; Lek, Dysoley; Rashid, Mohammad Abdur; By, Ngau Peng; Popovici, Jean; Huy, Rekol; Menard, Didier

    2016-01-01

    The Cambodian National Strategic Plan for Elimination of Malaria aims to move step by step toward elimination of malaria across Cambodia with an initial focus on Plasmodium falciparum malaria before achieving elimination of all forms of malaria, including Plasmodium vivax in 2025. The emergence of artemisinin-resistant P. falciparum in western Cambodia over the last decade has drawn global attention to support the ultimate goal of P. falciparum elimination, whereas the control of P. vivax lags much behind, making the 2025 target gradually less achievable unless greater attention is given to P. vivax elimination in the country. The following review presents in detail the past and current situation regarding P. vivax malaria, activities of the National Malaria Control Program, and interventional measures applied. Constraints and obstacles that can jeopardize our efforts to eliminate this parasite species are discussed. PMID:27708187

  18. Tetany with Plasmodium falciparum infection.

    PubMed

    Singh, P S; Singh, Neha

    2012-07-01

    Plasmodium falciparum is a malarial infection with high morbidity and wide spectrum of atypical presentation. Here we report an unusual presentation of malaria as tetany with alteration in calcium,phosphate and magnesium metabolism Hypocalcaemia in malaria can cause prolonged Q-Tc interval which could be arisk factor for quinine cardiotoxicity and sudden death Hence monitoring of serum calcium in severe malarial infection and cautious use of quinine in such patients is very important in management

  19. Global Epidemiology of Plasmodium vivax

    PubMed Central

    Howes, Rosalind E.; Battle, Katherine E.; Mendis, Kamini N.; Smith, David L.; Cibulskis, Richard E.; Baird, J. Kevin; Hay, Simon I.

    2016-01-01

    Plasmodium vivax is the most widespread human malaria, putting 2.5 billion people at risk of infection. Its unique biological and epidemiological characteristics pose challenges to control strategies that have been principally targeted against Plasmodium falciparum. Unlike P. falciparum, P. vivax infections have typically low blood-stage parasitemia with gametocytes emerging before illness manifests, and dormant liver stages causing relapses. These traits affect both its geographic distribution and transmission patterns. Asymptomatic infections, high-risk groups, and resulting case burdens are described in this review. Despite relatively low prevalence measurements and parasitemia levels, along with high proportions of asymptomatic cases, this parasite is not benign. Plasmodium vivax can be associated with severe and even fatal illness. Spreading resistance to chloroquine against the acute attack, and the operational inadequacy of primaquine against the multiple attacks of relapse, exacerbates the risk of poor outcomes among the tens of millions suffering from infection each year. Without strategies accounting for these P. vivax-specific characteristics, progress toward elimination of endemic malaria transmission will be substantially impeded. PMID:27402513

  20. Detection of Plasmodium sp. in capybara.

    PubMed

    dos Santos, Leonilda Correia; Curotto, Sandra Mara Rotter; de Moraes, Wanderlei; Cubas, Zalmir Silvino; Costa-Nascimento, Maria de Jesus; de Barros Filho, Ivan Roque; Biondo, Alexander Welker; Kirchgatter, Karin

    2009-07-07

    In the present study, we have microscopically and molecularly surveyed blood samples from 11 captive capybaras (Hydrochaeris hydrochaeris) from the Sanctuary Zoo for Plasmodium sp. infection. One animal presented positive on blood smear by light microscopy. Polymerase chain reaction was carried out accordingly using a nested genus-specific protocol, which uses oligonucleotides from conserved sequences flanking a variable sequence region in the small subunit ribosomal RNA (ssrRNA) of all Plasmodium organisms. This revealed three positive animals. Products from two samples were purified and sequenced. The results showed less than 1% divergence between the two capybara sequences. When compared with GenBank sequences, a 55% similarity was obtained to Toxoplasma gondii and a higher similarity (73-77.2%) was found to ssrRNAs from Plasmodium species that infect reptile, avian, rodents, and human beings. The most similar Plasmodium sequence was from Plasmodium mexicanum that infects lizards of North America, where around 78% identity was found. This work is the first report of Plasmodium in capybaras, and due to the low similarity with other Plasmodium species, we suggest it is a new species, which, in the future could be denominated "Plasmodium hydrochaeri".

  1. Plasmodium falciparum picks (on) EPCR

    PubMed Central

    Mosnier, Laurent O.; Fairhurst, Rick M.

    2014-01-01

    Of all the outcomes of Plasmodium falciparum infection, the coma of cerebral malaria (CM) is particularly deadly. Malariologists have long wondered how some patients develop this organ-specific syndrome. Data from two recent publications support a novel mechanism of CM pathogenesis in which infected erythrocytes (IEs) express specific virulence proteins that mediate IE binding to the endothelial protein C receptor (EPCR). Malaria-associated depletion of EPCR, with subsequent impairment of the protein C system promotes a proinflammatory, procoagulant state in brain microvessels. PMID:24246501

  2. Control of Plasmodium knowlesi malaria

    NASA Astrophysics Data System (ADS)

    Abdullahi, Mohammed Baba; Hasan, Yahya Abu; Abdullah, Farah Aini

    2015-10-01

    The most significant and efficient measures against Plasmodium knowlesi outbreaks are efficient anti malaria drug, biological control in form of predatory mosquitoes and culling control strategies. In this paper optimal control theory is applied to a system of ordinary differential equation. It describes the disease transmission and Pontryagin's Maximum Principle is applied for analysis of the control. To this end, three control strategies representing biological control, culling and treatment were incorporated into the disease transmission model. The simulation results show that the implementation of the combination strategy during the epidemic is the most cost-effective strategy for disease transmission.

  3. The periodicity of Plasmodium vivax and Plasmodium falciparum in Venezuela.

    PubMed

    Grillet, María-Eugenia; El Souki, Mayida; Laguna, Francisco; León, José Rafael

    2014-01-01

    We investigated the periodicity of Plasmodium vivax and P. falciparum incidence in time-series of malaria data (1990-2010) from three endemic regions in Venezuela. In particular, we determined whether disease epidemics were related to local climate variability and regional climate anomalies such as the El Niño Southern Oscillation (ENSO). Malaria periodicity was found to exhibit unique features in each studied region. Significant multi-annual cycles of 2- to about 6-year periods were identified. The inter-annual variability of malaria cases was coherent with that of SSTs (ENSO), mainly at temporal scales within the 3-6 year periods. Additionally, malaria cases were intensified approximately 1 year after an El Niño event, a pattern that highlights the role of climate inter-annual variability in the epidemic patterns. Rainfall mediated the effect of ENSO on malaria locally. Particularly, rains from the last phase of the season had a critical role in the temporal dynamics of Plasmodium. The malaria-climate relationship was complex and transient, varying in strength with the region and species. By identifying temporal cycles of malaria we have made a first step in predicting high-risk years in Venezuela. Our findings emphasize the importance of analyzing high-resolution spatial-temporal data to better understand malaria transmission dynamics.

  4. The NIMA-related kinase NEK1 cycles through the nucleus

    SciTech Connect

    Hilton, Laura K.; White, Mark C.; Quarmby, Lynne M.

    2009-11-06

    Mutations in NEK1 in mice are causal for cystic kidneys, and model the ciliopathy polycystic kidney disease caused by abnormal ciliary structure or signaling. NEK1 has previously been shown to localize near centrosomes and to play a role in centrosomal stability and ciliogenesis. Recent data suggest that the etiology of kidney cysts involves aberrant signaling from the primary cilium to the nucleus. Here we demonstrate that NEK1 contains functional nuclear localization signals, is exported from the nucleus via a nuclear export signal-dependent pathway and that the protein cycles through the nucleus. Our data suggest that NEK1 is a candidate to transduce messages from the ciliary-basal body region to the regulation of nuclear gene expression.

  5. Integrated analysis of the Plasmodium species transcriptome.

    PubMed

    Hoo, Regina; Zhu, Lei; Amaladoss, Anburaj; Mok, Sachel; Natalang, Onguma; Lapp, Stacey A; Hu, Guangan; Liew, Kingsley; Galinski, Mary R; Bozdech, Zbynek; Preiser, Peter R

    2016-05-01

    The genome sequence available for different Plasmodium species is a valuable resource for understanding malaria parasite biology. However, comparative genomics on its own cannot fully explain all the species-specific differences which suggests that other genomic aspects such as regulation of gene expression play an important role in defining species-specific characteristics. Here, we developed a comprehensive approach to measure transcriptional changes of the evolutionary conserved syntenic orthologs during the intraerythrocytic developmental cycle across six Plasmodium species. We show significant transcriptional constraint at the mid-developmental stage of Plasmodium species while the earliest stages of parasite development display the greatest transcriptional variation associated with critical functional processes. Modeling of the evolutionary relationship based on changes in transcriptional profile reveal a phylogeny pattern of the Plasmodium species that strictly follows its mammalian hosts. In addition, the work shows that transcriptional conserved orthologs represent potential future targets for anti-malaria intervention as they would be expected to carry out key essential functions within the parasites. This work provides an integrated analysis of orthologous transcriptome, which aims to provide insights into the Plasmodium evolution thereby establishing a framework to explore complex pathways and drug discovery in Plasmodium species with broad host range. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  6. Isoprenoid Biosynthesis in Plasmodium falciparum

    PubMed Central

    Guggisberg, Ann M.; Amthor, Rachel E.

    2014-01-01

    Malaria kills nearly 1 million people each year, and the protozoan parasite Plasmodium falciparum has become increasingly resistant to current therapies. Isoprenoid synthesis via the methylerythritol phosphate (MEP) pathway represents an attractive target for the development of new antimalarials. The phosphonic acid antibiotic fosmidomycin is a specific inhibitor of isoprenoid synthesis and has been a helpful tool to outline the essential functions of isoprenoid biosynthesis in P. falciparum. Isoprenoids are a large, diverse class of hydrocarbons that function in a variety of essential cellular processes in eukaryotes. In P. falciparum, isoprenoids are used for tRNA isopentenylation and protein prenylation, as well as the synthesis of vitamin E, carotenoids, ubiquinone, and dolichols. Recently, isoprenoid synthesis in P. falciparum has been shown to be regulated by a sugar phosphatase. We outline what is known about isoprenoid function and the regulation of isoprenoid synthesis in P. falciparum, in order to identify valuable directions for future research. PMID:25217461

  7. Chemical genetics of Plasmodium falciparum

    PubMed Central

    Guiguemde, W. Armand; Shelat, Anang A.; Bouck, David; Duffy, Sandra; Crowther, Gregory J.; Davis, Paul H.; Smithson, David C.; Connelly, Michele; Clark, Julie; Zhu, Fangyi; Jiménez-Díaz, María B; Martinez, María S; Wilson, Emily B.; Tripathi, Abhai K.; Gut, Jiri; Sharlow, Elizabeth R.; Bathurst, Ian; El Mazouni, Farah; Fowble, Joseph W; Forquer, Isaac; McGinley, Paula L; Castro, Steve; Angulo-Barturen, Iñigo; Ferrer, Santiago; Rosenthal, Philip J.; DeRisi, Joseph L; Sullivan, David J.; Lazo, John S.; Roos, David S.; Riscoe, Michael K.; Phillips, Margaret A.; Rathod, Pradipsinh K.; Van Voorhis, Wesley C.; Avery, Vicky M; Guy, R. Kiplin

    2010-01-01

    Malaria caused by Plasmodium falciparum is a catastrophic disease worldwide (880,000 deaths yearly). Vaccine development has proved difficult and resistance has emerged for most antimalarials. In order to discover new antimalarial chemotypes, we have employed a phenotypic forward chemical genetic approach to assay 309,474 chemicals. Here we disclose structures and biological activity of the entire library, many of which exhibited potent in vitro activity against drug resistant strains, and detailed profiling of 172 representative candidates. A reverse chemical genetic study identified 19 new inhibitors of 4 validated drug targets and 15 novel binders among 61 malarial proteins. Phylochemogenetic profiling in multiple organisms revealed similarities between Toxoplasma gondii and mammalian cell lines and dissimilarities between P. falciparum and related protozoans. One exemplar compound displayed efficacy in a murine model. Overall, our findings provide the scientific community with new starting points for malaria drug discovery. PMID:20485428

  8. Plasmodium vivax Transmission in Africa

    PubMed Central

    Howes, Rosalind E.; Reiner Jr., Robert C.; Battle, Katherine E.; Longbottom, Joshua; Mappin, Bonnie; Ordanovich, Dariya; Tatem, Andrew J.; Drakeley, Chris; Gething, Peter W.; Zimmerman, Peter A.; Smith, David L.; Hay, Simon I.

    2015-01-01

    Malaria in sub-Saharan Africa has historically been almost exclusively attributed to Plasmodium falciparum (Pf). Current diagnostic and surveillance systems in much of sub-Saharan Africa are not designed to identify or report non-Pf human malaria infections accurately, resulting in a dearth of routine epidemiological data about their significance. The high prevalence of Duffy negativity provided a rationale for excluding the possibility of Plasmodium vivax (Pv) transmission. However, review of varied evidence sources including traveller infections, community prevalence surveys, local clinical case reports, entomological and serological studies contradicts this viewpoint. Here, these data reports are weighted in a unified framework to reflect the strength of evidence of indigenous Pv transmission in terms of diagnostic specificity, size of individual reports and corroboration between evidence sources. Direct evidence was reported from 21 of the 47 malaria-endemic countries studied, while 42 countries were attributed with infections of visiting travellers. Overall, moderate to conclusive evidence of transmission was available from 18 countries, distributed across all parts of the continent. Approximately 86.6 million Duffy positive hosts were at risk of infection in Africa in 2015. Analysis of the mechanisms sustaining Pv transmission across this continent of low frequency of susceptible hosts found that reports of Pv prevalence were consistent with transmission being potentially limited to Duffy positive populations. Finally, reports of apparent Duffy-independent transmission are discussed. While Pv is evidently not a major malaria parasite across most of sub-Saharan Africa, the evidence presented here highlights its widespread low-level endemicity. An increased awareness of Pv as a potential malaria parasite, coupled with policy shifts towards species-specific diagnostics and reporting, will allow a robust assessment of the public health significance of Pv, as well

  9. Plasmodium vivax Transmission in Africa.

    PubMed

    Howes, Rosalind E; Reiner, Robert C; Battle, Katherine E; Longbottom, Joshua; Mappin, Bonnie; Ordanovich, Dariya; Tatem, Andrew J; Drakeley, Chris; Gething, Peter W; Zimmerman, Peter A; Smith, David L; Hay, Simon I

    2015-11-01

    Malaria in sub-Saharan Africa has historically been almost exclusively attributed to Plasmodium falciparum (Pf). Current diagnostic and surveillance systems in much of sub-Saharan Africa are not designed to identify or report non-Pf human malaria infections accurately, resulting in a dearth of routine epidemiological data about their significance. The high prevalence of Duffy negativity provided a rationale for excluding the possibility of Plasmodium vivax (Pv) transmission. However, review of varied evidence sources including traveller infections, community prevalence surveys, local clinical case reports, entomological and serological studies contradicts this viewpoint. Here, these data reports are weighted in a unified framework to reflect the strength of evidence of indigenous Pv transmission in terms of diagnostic specificity, size of individual reports and corroboration between evidence sources. Direct evidence was reported from 21 of the 47 malaria-endemic countries studied, while 42 countries were attributed with infections of visiting travellers. Overall, moderate to conclusive evidence of transmission was available from 18 countries, distributed across all parts of the continent. Approximately 86.6 million Duffy positive hosts were at risk of infection in Africa in 2015. Analysis of the mechanisms sustaining Pv transmission across this continent of low frequency of susceptible hosts found that reports of Pv prevalence were consistent with transmission being potentially limited to Duffy positive populations. Finally, reports of apparent Duffy-independent transmission are discussed. While Pv is evidently not a major malaria parasite across most of sub-Saharan Africa, the evidence presented here highlights its widespread low-level endemicity. An increased awareness of Pv as a potential malaria parasite, coupled with policy shifts towards species-specific diagnostics and reporting, will allow a robust assessment of the public health significance of Pv, as well

  10. Orangutans not infected with Plasmodium vivax or P. cynomolgi, Indonesia.

    PubMed

    Singh, Balbir; Simon Divis, Paul Cliff

    2009-10-01

    After orangutans in Indonesia were reported as infected with Plasmodium cynomolgi and P. vivax, we conducted phylogenetic analyses of small subunit ribosomal RNA gene sequences of Plasmodium spp. We found that these orangutans are not hosts of P. cynomolgi and P. vivax. Analysis of >or=1 genes is needed to identify Plasmodium spp. infecting orangutans.

  11. Complicated malaria: a rare presentation of Plasmodium ovale.

    PubMed

    Tomar, Laxmikant Ramkumarsingh; Giri, Subhash; Bauddh, Nitesh Kumar; Jhamb, Rajat

    2015-04-01

    Malaria has emerged as a major public health problem worldwide. Complications are commonly seen in Plasmodium falciparum (P. falciparum) and Plasmodium vivax (P. vivax) infection, but due to Plasmodium ovale (P. ovale) infection is rarely described in literature. Here we report a case of severe disease due to P. ovale infection complicated with jaundice, thrombocytopenia, hypotension and acute renal failure.

  12. Proteomic Approaches to Studying Drug Targets and Resistance in Plasmodium

    DTIC Science & Technology

    2004-01-01

    Plasmodium falciparum , the most virulent of human malaria parasites, is creating new challenges in malaria chemotherapy. The entire genome sequences of...P. falciparum and the rodent malaria parasite, P. yoelii yoelii are now available. Extensive genome sequence data from other Plasmodium species...Parasite, Protein, Mass Spectrometry, Genomics, Chloroquine, Artemisinin INTRODUCTION Research on Plasmodium falciparum , a protozoan parasite and

  13. Helminth Parasites Alter Protection against Plasmodium Infection

    PubMed Central

    Salazar-Castañon, Víctor H.; Legorreta-Herrera, Martha

    2014-01-01

    More than one-third of the world's population is infected with one or more helminthic parasites. Helminth infections are prevalent throughout tropical and subtropical regions where malaria pathogens are transmitted. Malaria is the most widespread and deadliest parasitic disease. The severity of the disease is strongly related to parasite density and the host's immune responses. Furthermore, coinfections between both parasites occur frequently. However, little is known regarding how concomitant infection with helminths and Plasmodium affects the host's immune response. Helminthic infections are frequently massive, chronic, and strong inductors of a Th2-type response. This implies that infection by such parasites could alter the host's susceptibility to subsequent infections by Plasmodium. There are a number of reports on the interactions between helminths and Plasmodium; in some, the burden of Plasmodium parasites increased, but others reported a reduction in the parasite. This review focuses on explaining many of these discrepancies regarding helminth-Plasmodium coinfections in terms of the effects that helminths have on the immune system. In particular, it focuses on helminth-induced immunosuppression and the effects of cytokines controlling polarization toward the Th1 or Th2 arms of the immune response. PMID:25276830

  14. Helminth parasites alter protection against Plasmodium infection.

    PubMed

    Salazar-Castañon, Víctor H; Legorreta-Herrera, Martha; Rodriguez-Sosa, Miriam

    2014-01-01

    More than one-third of the world's population is infected with one or more helminthic parasites. Helminth infections are prevalent throughout tropical and subtropical regions where malaria pathogens are transmitted. Malaria is the most widespread and deadliest parasitic disease. The severity of the disease is strongly related to parasite density and the host's immune responses. Furthermore, coinfections between both parasites occur frequently. However, little is known regarding how concomitant infection with helminths and Plasmodium affects the host's immune response. Helminthic infections are frequently massive, chronic, and strong inductors of a Th2-type response. This implies that infection by such parasites could alter the host's susceptibility to subsequent infections by Plasmodium. There are a number of reports on the interactions between helminths and Plasmodium; in some, the burden of Plasmodium parasites increased, but others reported a reduction in the parasite. This review focuses on explaining many of these discrepancies regarding helminth-Plasmodium coinfections in terms of the effects that helminths have on the immune system. In particular, it focuses on helminth-induced immunosuppression and the effects of cytokines controlling polarization toward the Th1 or Th2 arms of the immune response.

  15. Anopheles Midgut FREP1 Mediates Plasmodium Invasion*

    PubMed Central

    Zhang, Genwei; Niu, Guodong; Franca, Caio M.; Dong, Yuemei; Wang, Xiaohong; Butler, Noah S.; Dimopoulos, George; Li, Jun

    2015-01-01

    Malaria transmission depends on sexual stage Plasmodium parasites successfully invading Anopheline mosquito midguts following a blood meal. However, the molecular mechanisms of Plasmodium invasion of mosquito midguts have not been fully elucidated. Previously, we showed that genetic polymorphisms in the fibrinogen-related protein 1 (FREP1) gene are significantly associated with Plasmodium falciparum infection in Anopheles gambiae, and FREP1 is important for Plasmodium berghei infection of mosquitoes. Here we identify that the FREP1 protein is secreted from the mosquito midgut epithelium and integrated as tetramers into the peritrophic matrix, a chitinous matrix formed inside the midgut lumen after a blood meal feeding. Moreover, we show that the FREP1 can directly bind Plasmodia sexual stage gametocytes and ookinetes. Notably, ablating FREP1 expression or targeting FREP1 with antibodies significantly decreases P. falciparum infection in mosquito midguts. Our data support that the mosquito-expressed FREP1 mediates mosquito midgut invasion by multiple species of Plasmodium parasites via anchoring ookinetes to the peritrophic matrix and enabling parasites to penetrate the peritrophic matrix and the epithelium. Thus, targeting FREP1 can limit malaria transmission. PMID:25991725

  16. Accurate identification of the six human Plasmodium spp. causing imported malaria, including Plasmodium ovale wallikeri and Plasmodium knowlesi.

    PubMed

    Calderaro, Adriana; Piccolo, Giovanna; Gorrini, Chiara; Rossi, Sabina; Montecchini, Sara; Dell'Anna, Maria Loretana; De Conto, Flora; Medici, Maria Cristina; Chezzi, Carlo; Arcangeletti, Maria Cristina

    2013-09-13

    Accurate identification of Plasmodium infections in non-endemic countries is of critical importance with regard to the administration of a targeted therapy having a positive impact on patient health and management and allowing the prevention of the risk of re-introduction of endemic malaria in such countries. Malaria is no longer endemic in Italy where it is the most commonly imported disease, with one of the highest rates of imported malaria among European non-endemic countries including France, the UK and Germany, and with a prevalence of 24.3% at the University Hospital of Parma. Molecular methods showed high sensitivity and specificity and changed the epidemiology of imported malaria in several non-endemic countries, highlighted a higher prevalence of Plasmodium ovale, Plasmodium vivax and Plasmodium malariae underestimated by microscopy and, not least, brought to light both the existence of two species of P. ovale (Plasmodium ovale curtisi and Plasmodium ovale wallikeri) and the infection in humans by Plasmodium knowlesi, otherwise not detectable by microscopy. In this retrospective study an evaluation of two real-time PCR assays able to identify P. ovale wallikeri, distinguishing it from P. ovale curtisi, and to detect P. knowlesi, respectively, was performed applying them on a subset of 398 blood samples belonging to patients with the clinical suspicion of malaria. These assays revealed an excellent analytical sensitivity and no cross-reactivity versus other Plasmodium spp. infecting humans, suggesting their usefulness for an accurate and complete diagnosis of imported malaria. Among the 128 patients with malaria, eight P. ovale curtisi and four P. ovale wallikeri infections were detected, while no cases of P. knowlesi infection were observed. Real-time PCR assays specific for P. ovale wallikeri and P. knowlesi were included in the panel currently used in the University Hospital of Parma for the diagnosis of imported malaria, accomplishing the goal of

  17. Occurrence of Plasmodium in Anatidae

    USGS Publications Warehouse

    Herman, C.M.; Kocan, R.M.

    1970-01-01

    Until a little over a decade ago reports of Plasrnodium in geese, ducks, and swans were the result of examination of single blood smears from wild birds. One would gather from the earlier studies that Anatidae are infrequently infected. During the past decade we have conducted studies on prevalence of Plasmodium by an isodiagnosis technique, inoculating blood from wild birds into captive young geese, ducks, and other species of birds and determining the status of infection in the donors by examination of repetitive blood smears from the recipients. Examination by this technique of a series of adult Canada geese from the Seney National Wildlife Refuge in northern Michigan uncovered a prevalence of 60% during five successive years. Domestic geese were the primary recipients but we found that several other species of geese, ducks, and gulls were also susceptible. Similar studies on Canada geese from other areas (Maryland, New Jersey, New York, and southern Michigan) uncovered infection rates from zero to 27%. Following isolation of Plasmodlum in a single canvasback duck (Aythya valisineria) in southern Michigan by inoculation into a domestic duck, a series of 88 canvasbacks from Chesapeake Bay in Maryland this winter uncovered an infection rate of 27%. The most common parasite observed in both the geese and was as P. circumflexum.

  18. The anaemia of Plasmodium vivax malaria

    PubMed Central

    2012-01-01

    Plasmodium vivax threatens nearly half the world’s population and is a significant impediment to achievement of the millennium development goals. It is an important, but incompletely understood, cause of anaemia. This review synthesizes current evidence on the epidemiology, pathogenesis, treatment and consequences of vivax-associated anaemia. Young children are at high risk of clinically significant and potentially severe vivax-associated anaemia, particularly in countries where transmission is intense and relapses are frequent. Despite reaching lower densities than Plasmodium falciparum, Plasmodium vivax causes similar absolute reduction in red blood cell mass because it results in proportionately greater removal of uninfected red blood cells. Severe vivax anaemia is associated with substantial indirect mortality and morbidity through impaired resilience to co-morbidities, obstetric complications and requirement for blood transfusion. Anaemia can be averted by early and effective anti-malarial treatment. PMID:22540175

  19. The anaemia of Plasmodium vivax malaria.

    PubMed

    Douglas, Nicholas M; Anstey, Nicholas M; Buffet, Pierre A; Poespoprodjo, Jeanne R; Yeo, Tsin W; White, Nicholas J; Price, Ric N

    2012-04-27

    Plasmodium vivax threatens nearly half the world's population and is a significant impediment to achievement of the millennium development goals. It is an important, but incompletely understood, cause of anaemia. This review synthesizes current evidence on the epidemiology, pathogenesis, treatment and consequences of vivax-associated anaemia. Young children are at high risk of clinically significant and potentially severe vivax-associated anaemia, particularly in countries where transmission is intense and relapses are frequent. Despite reaching lower densities than Plasmodium falciparum, Plasmodium vivax causes similar absolute reduction in red blood cell mass because it results in proportionately greater removal of uninfected red blood cells. Severe vivax anaemia is associated with substantial indirect mortality and morbidity through impaired resilience to co-morbidities, obstetric complications and requirement for blood transfusion. Anaemia can be averted by early and effective anti-malarial treatment.

  20. Promoter regions of Plasmodium vivax are poorly or not recognized by Plasmodium falciparum

    PubMed Central

    Azevedo, Mauro F; del Portillo, Hernando A

    2007-01-01

    Background Heterologous promoter analysis in Plasmodium has revealed the existence of conserved cis regulatory elements as promoters from different species can drive expression of reporter genes in heterologous transfection assays. Here, the functional characterization of different Plasmodium vivax promoters in Plasmodium falciparum using luciferase as the reporter gene is presented. Methods Luciferase reporter plasmids harboring the upstream regions of the msp1, dhfr, and vir3 genes as well as the full-length intergenic regions of the vir23/24 and ef-1α genes of P. vivax were constructed and transiently transfected in P. falciparum. Results Only the constructs with the full-length intergenic regions of the vir23/24 and ef-1α genes were recognized by the P. falciparum transcription machinery albeit to values approximately two orders of magnitude lower than those reported by luc plasmids harbouring promoter regions from P. falciparum and Plasmodium berghei. A bioinformatics approach allowed the identification of a motif (GCATAT) in the ef-1α intergenic region that is conserved in five Plasmodium species but is degenerate (GCANAN) in P. vivax. Mutations of this motif in the P. berghei ef-1α promoter region decreased reporter expression indicating it is active in gene expression in Plasmodium. Conclusion Together, this data indicates that promoter regions of P. vivax are poorly or not recognized by the P. falciparum transcription machinery suggesting the existence of P. vivax-specific transcription regulatory elements. PMID:17313673

  1. Congenital Plasmodium falciparum Malaria in Washington, DC.

    PubMed

    Del Castillo, Melissa; Szymanski, Ann Marie; Slovin, Ariella; Wong, Edward C C; DeBiasi, Roberta L

    2017-01-11

    Congenital malaria is rare in the United States, but is an important diagnosis to consider when evaluating febrile infants. Herein, we describe a case of congenital Plasmodium falciparum malaria in a 2-week-old infant born in the United States to a mother who had emigrated from Nigeria 3 months before delivery. © The American Society of Tropical Medicine and Hygiene.

  2. Human Infections with Plasmodium knowlesi, the Philippines

    PubMed Central

    Espino, Fe; Curameng, Peter; Espina, Ronald; Bell, David; Chiodini, Peter; Nolder, Debbie; Sutherland, Colin; Lee, Kim-Sung; Singh, Balbir

    2008-01-01

    Five human cases of infection with the simian malaria parasite Plasmodium knowlesi from Palawan, the Philippines, were confirmed by nested PCR. This study suggests that this zoonotic infection is found across a relatively wide area in Palawan and documents autochthonous cases in the country. PMID:18439369

  3. Epidemiology of Plasmodium vivax Malaria in India.

    PubMed

    Anvikar, Anupkumar R; Shah, Naman; Dhariwal, Akshay C; Sonal, Gagan Singh; Pradhan, Madan Mohan; Ghosh, Susanta K; Valecha, Neena

    2016-12-28

    Historically, malaria in India was predominantly caused by Plasmodium vivax, accounting for 53% of the estimated cases. After the spread of drug-resistant Plasmodium falciparum in the 1990s, the prevalence of the two species remained equivalent at the national level for a decade. By 2014, the proportion of P. vivax has decreased to 34% nationally, but with high regional variation. In 2014, P. vivax accounted for around 380,000 malaria cases in India; almost a sixth of all P. vivax cases reported globally. Plasmodium vivax has remained resistant to control measures, particularly in urban areas. Urban malaria is predominantly caused by P. vivax and is subject to outbreaks, often associated with increased mortality, and triggered by bursts of migration and construction. The epidemiology of P. vivax varies substantially within India, including multiple relapse phenotypes with varying latencies between primary infection and relapse. Moreover, the hypnozoite reservoir maintains transmission potential and enables reestablishment of the parasite in areas in which it was thought eradicated. The burden of malaria in India is complex because of the highly variable malaria eco-epidemiological profiles, transmission factors, and the presence of multiple Plasmodium species and Anopheles vectors. This review of P. vivax malaria in India describes epidemiological trends with particular attention to four states: Gujarat, Karnataka, Haryana, and Odisha.

  4. Plasmodium falciparum Malaria, Southern Algeria, 2007

    PubMed Central

    Gassen, Ibrahim; Khechache, Yacine; Lamali, Karima; Tchicha, Boualem; Brengues, Cécile; Menegon, Michela; Severini, Carlo; Fontenille, Didier; Harrat, Zoubir

    2010-01-01

    An outbreak of Plasmodium falciparum malaria occurred in Tinzaouatine in southern Algeria in 2007. The likely vector, Anopheles gambiae mosquitoes, had not been detected in Algeria. Genes for resistance to chloroquine were detected in the parasite. The outbreak shows the potential for an increase in malaria vectors in Algeria. PMID:20113565

  5. Acute renal failure in Plasmodium malariae infection.

    PubMed

    Neri, S; Pulvirenti, D; Patamia, I; Zoccolo, A; Castellino, P

    2008-04-01

    We report an unusual case of transfusion-transmitted malaria which remained undiagnosed for several months in an Italian woman splenectomised and polytransfused for thalassaemia major. The infecting species was Plasmodium malariae, and the patient developed acute renal failure, severe thrombocytopenia, and hepatic failure. Treatment with chlorochine was followed by a slow, but complete recovery of renal function.

  6. Spatial Epidemiology of Plasmodium vivax, Afghanistan

    PubMed Central

    Leslie, Toby; Kolaczinski, Kate; Mohsen, Engineer; Mehboob, Najeebullah; Saleheen, Sarah; Khudonazarov, Juma; Freeman, Tim; Clements, Archie; Rowland, Mark; Kolaczinski, Jan

    2006-01-01

    Plasmodium vivax is endemic to many areas of Afghanistan. Geographic analysis helped highlight areas of malaria risk and clarified ecologic risk factors for transmission. Remote sensing enabled development of a risk map, thereby providing a valuable tool to help guide malaria control strategies. PMID:17176583

  7. Epidemiology of Plasmodium vivax Malaria in India

    PubMed Central

    Anvikar, Anupkumar R.; Shah, Naman; Dhariwal, Akshay C.; Sonal, Gagan Singh; Pradhan, Madan Mohan; Ghosh, Susanta K.; Valecha, Neena

    2016-01-01

    Historically, malaria in India was predominantly caused by Plasmodium vivax, accounting for 53% of the estimated cases. After the spread of drug-resistant Plasmodium falciparum in the 1990s, the prevalence of the two species remained equivalent at the national level for a decade. By 2014, the proportion of P. vivax has decreased to 34% nationally, but with high regional variation. In 2014, P. vivax accounted for around 380,000 malaria cases in India; almost a sixth of all P. vivax cases reported globally. Plasmodium vivax has remained resistant to control measures, particularly in urban areas. Urban malaria is predominantly caused by P. vivax and is subject to outbreaks, often associated with increased mortality, and triggered by bursts of migration and construction. The epidemiology of P. vivax varies substantially within India, including multiple relapse phenotypes with varying latencies between primary infection and relapse. Moreover, the hypnozoite reservoir maintains transmission potential and enables reestablishment of the parasite in areas in which it was thought eradicated. The burden of malaria in India is complex because of the highly variable malaria eco-epidemiological profiles, transmission factors, and the presence of multiple Plasmodium species and Anopheles vectors. This review of P. vivax malaria in India describes epidemiological trends with particular attention to four states: Gujarat, Karnataka, Haryana, and Odisha. PMID:27708188

  8. Plasmodium knowlesi in travellers, update 2014.

    PubMed

    Müller, Mattia; Schlagenhauf, Patricia

    2014-05-01

    Since the initial discovery of Plasmodium knowlesi in Malaysia, cases have been reported from several neighbouring countries. Tourism has also resulted in an increasing number of cases diagnosed in Europe, America, and Oceania. In this review we focus on the risk of the travel-associated acquisition of P. knowlesi malaria. A search of the literature in PubMed was carried out to identify articles and literature on the distribution of P. knowlesi infections in Southeast Asia and details of its acquisition and importation by travellers to other continents. The cut-off date for the search was December 1, 2013. Search words used were: "Plasmodium knowlesi", "Plasmodium knowlesi infections", "Plasmodium knowlesi travellers", "Plasmodium knowlesi prevalence", "Plasmodium knowlesi host", "Plasmodium knowlesi vector" "Plasmodium knowlesi RDT", and "Plasmodium knowlesi Malaysia". Traveller numbers to Malaysia were obtained from the Tourism Malaysia website. A total of 103 articles were found. Using a selection of these and others identified from the reference lists of the papers, we based our review on a total of 66 articles. P. knowlesi malaria appears to be the most common malaria species in Malaysian Borneo and is also widely distributed on the Malaysian mainland. Furthermore, locally transmitted cases of P. knowlesi malaria have been reported in Thailand, the Philippines, Vietnam, Singapore, Myanmar, Indonesian Borneo, and Cambodia. Two cases have been reported from non-endemic countries in Asia (Japan and Taiwan) in people with a history of travel to Malaysia and the Philippines. Twelve cases were imported to their home countries by travellers from other continents: two from the USA, two from the Netherlands, two from Germany, and one each from Spain, France, Sweden, Finland, Australia, and New Zealand. In most cases, the infection was associated with a trip to or near forested areas. The symptoms were fever (n=12), headache (n=6), chills (n=6), nausea (n=4), myalgia (n

  9. A case of Plasmodium ovale malaria imported from West Africa.

    PubMed

    Kang, Yunjung; Yang, Jinyoung

    2013-04-01

    Malaria is a parasitic infection caused by Plasmodium species. Most of the imported malaria in Korea are due to Plasmodium vivax and Plasmodium falciparum, and Plasmodium ovale infections are very rare. Here, we report a case of a 24-year-old American woman who acquired P. ovale while staying in Ghana, West Africa for 5 months in 2010. The patient was diagnosed with P. ovale malaria based on a Wright-Giemsa stained peripheral blood smear, Plasmodium genus-specific real-time PCR, Plasmodium species-specific nested PCR, and sequencing targeting 18S rRNA gene. The strain identified had a very long incubation period of 19-24 months. Blood donors who have malaria with a very long incubation period could be a potential danger for propagating malaria. Therefore, we should identify imported P. ovale infections not only by morphological findings but also by molecular methods for preventing propagation and appropriate treatment.

  10. Parasite Lactate Dehydrogenase for Diagnosis of Plasmodium Falciparum. Phase II.

    DTIC Science & Technology

    1997-04-01

    Diagnosis of Plasmodium Falciparum PRINCIPAL INVESTIGATOR: Robert C. Piper, Ph.D. CONTRACTING ORGANIZATION: Flow, Incorporated Portland, Oregon 97201...Phase 11 (24 Mar 95 - 23 Mar 97) 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS Parasite Lactate Dehydrogenase for Diagnosis of Plasmodium Falciparum DAMD...that infected patients become ill. Four species of Plasmodium infect humans. P. falciparum accounts for -85 % of the world’s malaria. P. falciparum is

  11. Filarial Worms Reduce Plasmodium Infectivity in Mosquitoes

    PubMed Central

    Aliota, Matthew T.; Chen, Cheng-Chen; Dagoro, Henry; Fuchs, Jeremy F.; Christensen, Bruce M.

    2011-01-01

    Background Co-occurrence of malaria and filarial worm parasites has been reported, but little is known about the interaction between filarial worm and malaria parasites with the same Anopheles vector. Herein, we present data evaluating the interaction between Wuchereria bancrofti and Anopheles punctulatus in Papua New Guinea (PNG). Our field studies in PNG demonstrated that An. punctulatus utilizes the melanization immune response as a natural mechanism of filarial worm resistance against invading W. bancrofti microfilariae. We then conducted laboratory studies utilizing the mosquitoes Armigeres subalbatus and Aedes aegypti and the parasites Brugia malayi, Brugia pahangi, Dirofilaria immitis, and Plasmodium gallinaceum to evaluate the hypothesis that immune activation and/or development by filarial worms negatively impact Plasmodium development in co-infected mosquitoes. Ar. subalbatus used in this study are natural vectors of P. gallinaceum and B. pahangi and they are naturally refractory to B. malayi (melanization-based refractoriness). Methodology/Principal Findings Mosquitoes were dissected and Plasmodium development was analyzed six days after blood feeding on either P. gallinaceum alone or after taking a bloodmeal containing both P. gallinaceum and B. malayi or a bloodmeal containing both P. gallinaceum and B. pahangi. There was a significant reduction in the prevalence and mean intensity of Plasmodium infections in two species of mosquito that had dual infections as compared to those mosquitoes that were infected with Plasmodium alone, and was independent of whether the mosquito had a melanization immune response to the filarial worm or not. However, there was no reduction in Plasmodium development when filarial worms were present in the bloodmeal (D. immitis) but midgut penetration was absent, suggesting that factors associated with penetration of the midgut by filarial worms likely are responsible for the observed reduction in malaria parasite infections

  12. Bifurcation in the chemotactic behavior of Physarum plasmodium

    NASA Astrophysics Data System (ADS)

    Shirakawa, Tomohiro; Gunji, Yukio-Pegio; Sato, Hiroshi; Tsubakino, Hiroto

    2017-07-01

    The plasmodium of true slime mold Physarum polycephalum is a unicellular and multinuclear giant amoeba. Since the cellular organism has some computational abilities, it is attracting much attention in the field of information science. However, previous studies have mainly focused on the optimization behavior of the plasmodium for a single-modality stimulus, and there are few studies on how the organism adapts to multi-modal stimuli. We stimulated the plasmodium with mixture of attractant and repellent stimuli, and we observed bifurcation in the chemotactic behavior of the plasmodium.

  13. Sugar activation and glycosylation in Plasmodium.

    PubMed

    Cova, Marta; Rodrigues, João A; Smith, Terry K; Izquierdo, Luis

    2015-10-31

    Glycoconjugates are important mediators of host-pathogen interactions and are usually very abundant in the surface of many protozoan parasites. However, in the particular case of Plasmodium species, previous works show that glycosylphosphatidylinositol anchor modifications, and to an unknown extent, a severely truncated N-glycosylation are the only glycosylation processes taking place in the parasite. Nevertheless, a detailed analysis of the parasite genome and the recent identification of the sugar nucleotide precursors biosynthesized by Plasmodium falciparum support a picture in which several overlooked, albeit not very prominent glycosylations may be occurring during the parasite life cycle. In this work, the authors review recent developments in the characterization of the biosynthesis of glycosylation precursors in the parasite, focusing on the outline of the possible fates of these precursors.

  14. Engineered Anopheles Immunity to Plasmodium Infection

    PubMed Central

    Cirimotich, Chris; Souza-Neto, Jayme A.; McLean, Kyle J.; Dimopoulos, George

    2011-01-01

    A causative agent of human malaria, Plasmodium falciparum, is transmitted by Anopheles mosquitoes. The malaria parasite is under intensive attack from the mosquito's innate immune system during its sporogonic development. We have used genetic engineering to create immune-enhanced Anopheles stephensi mosquitoes through blood meal-inducible expression of a transgene encoding the IMD pathway-controlled NF-kB Rel2 transcription factor in the midgut and fat-body tissue. Transgenic mosquitoes showed greater resistance to Plasmodium and microbial infection as a result of timely concerted tissue-specific immune attacks involving multiple effectors. The relatively weak impact of this genetic modification on mosquito fitness under laboratory conditions encourages further investigation of this approach for malaria control. PMID:22216006

  15. Engineered anopheles immunity to Plasmodium infection.

    PubMed

    Dong, Yuemei; Das, Suchismita; Cirimotich, Chris; Souza-Neto, Jayme A; McLean, Kyle J; Dimopoulos, George

    2011-12-01

    A causative agent of human malaria, Plasmodium falciparum, is transmitted by Anopheles mosquitoes. The malaria parasite is under intensive attack from the mosquito's innate immune system during its sporogonic development. We have used genetic engineering to create immune-enhanced Anopheles stephensi mosquitoes through blood meal-inducible expression of a transgene encoding the IMD pathway-controlled NF-kB Rel2 transcription factor in the midgut and fat-body tissue. Transgenic mosquitoes showed greater resistance to Plasmodium and microbial infection as a result of timely concerted tissue-specific immune attacks involving multiple effectors. The relatively weak impact of this genetic modification on mosquito fitness under laboratory conditions encourages further investigation of this approach for malaria control.

  16. Plasmodium Oocysts: Overlooked Targets of Mosquito Immunity.

    PubMed

    Smith, Ryan C; Barillas-Mury, Carolina

    2016-12-01

    Although the ability of mosquitoes to limit Plasmodium infection is well documented, many questions remain as to how malaria parasites are recognized and killed by the mosquito host. Recent evidence suggests that anti-Plasmodium immunity is multimodal, with different immune mechanisms regulating ookinete and oocyst survival. However, most experiments determine the number of mature oocysts, without considering that different immune mechanisms may target different developmental stages of the parasite. Complement-like proteins have emerged as important determinants of early immunity targeting the ookinete stage, yet the mechanisms by which the mosquito late-phase immune response limits oocyst survival are less understood. Here, we describe the known components of the mosquito immune system that limit oocyst development, and provide insight into their possible mechanisms of action. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Plasmodium cynomolgi genome sequences provide insight into Plasmodium vivax and the monkey malaria clade

    PubMed Central

    Tachibana, Shin-Ichiro; Sullivan, Steven A.; Kawai, Satoru; Nakamura, Shota; Kim, Hyunjae R.; Goto, Naohisa; Arisue, Nobuko; Palacpac, Nirianne M. Q.; Honma, Hajime; Yagi, Masanori; Tougan, Takahiro; Katakai, Yuko; Kaneko, Osamu; Mita, Toshihiro; Kita, Kiyoshi; Yasutomi, Yasuhiro; Sutton, Patrick L.; Shakhbatyan, Rimma; Horii, Toshihiro; Yasunaga, Teruo; Barnwell, John W.; Escalante, Ananias A.; Carlton, Jane M.; Tanabe, Kazuyuki

    2013-01-01

    Plasmodium cynomolgi, a malaria parasite of Asian Old World monkeys, is the sister taxon of Plasmodium vivax, the most prevalent human malaria species outside Africa. Since P. cynomolgi shares many phenotypic, biologic and genetic characteristics of P. vivax, we generated draft genome sequences of three P. cynomolgi strains and performed comparative genomic analysis between them and P. vivax, as well as a third previously sequenced simian parasite, Plasmodium knowlesi. Here we show that genomes of the monkey malaria clade can be characterized by CNVs in multigene families involved in evasion of the human immune system and invasion of host erythrocytes. We identify genome-wide SNPs, microsatellites, and CNVs in the P. cynomolgi genome, providing a map of genetic variation for mapping parasite traits and studying parasite populations. The P. cynomolgi genome is a critical step in developing a model system for P. vivax research, and to counteract the neglect of P. vivax. PMID:22863735

  18. Plasmodium vivax trophozoites insensitive to chloroquine

    PubMed Central

    Sharrock, Wesley W; Suwanarusk, Rossarin; Lek-Uthai, Usa; Edstein, Michael D; Kosaisavee, Varakorn; Travers, Thomas; Jaidee, Anchalee; Sriprawat, Kanlaya; Price, Ric N; Nosten, François; Russell, Bruce

    2008-01-01

    Background Plasmodium vivax is a major cause of malaria and is still primarily treated with chloroquine. Chloroquine inhibits the polymerization of haem to inert haemozoin. Free haem monomers are thought to catalyze oxidative damage to the Plasmodium spp. trophozoite, the stage when haemoglobin catabolism is maximal. However preliminary in vitro observations on P. vivax clinical isolates suggest that only ring stages (early trophozoites) are sensitive to chloroquine. In this study, the stage specific action of chloroquine was investigated in synchronous cryopreserved isolates of P. vivax. Methods The in vitro chloroquine sensitivity of paired ring and trophozoite stages from 11 cryopreserved P. vivax clinical isolates from Thailand and two Plasmodium falciparum clones (chloroquine resistant K1 and chloroquine sensitive FC27) was measured using a modified WHO microtest method and fluorometric SYBR Green I Assay. The time each stage was exposed to chloroquine treatment was controlled by washing the chloroquine off at 20 hours after the beginning of treatment. Results Plasmodium vivax isolates added to the assay at ring stage had significantly lower median IC50s to chloroquine than the same isolates added at trophozoite stage (median IC50 12 nM vs 415 nM p < 0.01). Although only 36% (4/11) of the SYBR Green I assays for P. vivax were successful, both microscopy and SYBR Green I assays indicated that only P. vivax trophozoites were able to develop to schizonts at chloroquine concentrations above 100 nM. Conclusion Data from this study confirms the diminished sensitivity of P. vivax trophozoites to chloroquine, the stage thought to be the target of this drug. These results raise important questions about the pharmacodynamic action of chloroquine, and highlight a fundamental difference in the activity of chloroquine between P. vivax and P. falciparum. PMID:18505560

  19. Plasmodium malariae in Haitian Refugees, Jamaica

    PubMed Central

    Bryce, Jeanette Horner; Ducasse, Marion Bullock; Howitt, Christina; Barrett, Donnett M.; Morales, Jacob Lorenzo; Ord, Rosalynn; Burke, Martina; Chiodini, Peter L.; Sutherland, Colin J.

    2007-01-01

    Since 1963, reported malaria transmission in Haiti has been restricted to Plasmodium falciparum. However, screening of Haitian refugees in Jamaica in 2004, by microscopic examination, identified P. falciparum, P. vivax, and P. malariae. PCR confirmed the P. malariae and P. falciparum but not P. vivax infections. DNA sequencing and rRNA gene sequences showed transmission of P. malariae. This report confirms that P. malariae is still being transmitted in Haiti. PMID:17553241

  20. Epidemiology of Plasmodium vivax in Indonesia

    PubMed Central

    Surjadjaja, Claudia; Surya, Asik; Baird, J. Kevin

    2016-01-01

    Endemic malaria occurs across much of the vast Indonesian archipelago. All five species of Plasmodium known to naturally infect humans occur here, along with 20 species of Anopheles mosquitoes confirmed as carriers of malaria. Two species of plasmodia cause the overwhelming majority and virtually equal shares of malaria infections in Indonesia: Plasmodium falciparum and Plasmodium vivax. The challenge posed by P. vivax is especially steep in Indonesia because chloroquine-resistant strains predominate, along with Chesson-like strains that relapse quickly and multiple times at short intervals in almost all patients. Indonesia's hugely diverse human population carries many variants of glucose-6-phosphate dehydrogenase (G6PD) deficiency, most of them exhibiting severely impaired enzyme activity. Therefore, the patients most likely to benefit from primaquine therapy by preventing aggressive relapse, may also be most likely to suffer harm without G6PD deficiency screening. Indonesia faces the challenge of controlling and eventually eliminating malaria across > 13,500 islands stretching > 5,000 km and an enormous diversity of ecological, ethnographic, and socioeconomic settings, and extensive human migrations. This article describes the occurrence of P. vivax in Indonesia and the obstacles faced in eliminating its transmission. PMID:27708185

  1. Epidemiology of Plasmodium vivax in Indonesia.

    PubMed

    Surjadjaja, Claudia; Surya, Asik; Baird, J Kevin

    2016-12-28

    Endemic malaria occurs across much of the vast Indonesian archipelago. All five species of Plasmodium known to naturally infect humans occur here, along with 20 species of Anopheles mosquitoes confirmed as carriers of malaria. Two species of plasmodia cause the overwhelming majority and virtually equal shares of malaria infections in Indonesia: Plasmodium falciparum and Plasmodium vivax The challenge posed by P. vivax is especially steep in Indonesia because chloroquine-resistant strains predominate, along with Chesson-like strains that relapse quickly and multiple times at short intervals in almost all patients. Indonesia's hugely diverse human population carries many variants of glucose-6-phosphate dehydrogenase (G6PD) deficiency, most of them exhibiting severely impaired enzyme activity. Therefore, the patients most likely to benefit from primaquine therapy by preventing aggressive relapse, may also be most likely to suffer harm without G6PD deficiency screening. Indonesia faces the challenge of controlling and eventually eliminating malaria across > 13,500 islands stretching > 5,000 km and an enormous diversity of ecological, ethnographic, and socioeconomic settings, and extensive human migrations. This article describes the occurrence of P. vivax in Indonesia and the obstacles faced in eliminating its transmission. © The American Society of Tropical Medicine and Hygiene.

  2. Plasmodium knowlesi infection: a diagnostic challenge

    PubMed Central

    Fan, Lijia; Lee, Shir Ying; Koay, Evelyn; Harkensee, Christian

    2013-01-01

    Plasmodium knowlesi malaria is an uncommon, but highly prevalent parasitic infection in parts of Malaysia. This is the case of a 14-year-old Singaporean boy presenting to our emergency department with an 11-day history of fever following a school trip to Malaysia. Hepatosplenomegaly was the only clinical finding; laboratory tests showed thrombocytopaenia, lymphopaenia, mild anaemia and liver transaminitis. Specific malaria antigen tests were negative, but the peripheral blood film showed plasmodia with atypical features, with a parasite load of 0.5%. PCR confirmed the diagnosis of P knowlesi. The patient was successfully treated with chloroquine. The clinical course of P knowlesi malaria is indistinguishable from that of Plasmodium falciparum. This case highlights the importance of taking detailed travel history, careful examination of malaria blood films and judicious use of molecular techniques. Antigen tests alone may have missed a malaria diagnosis altogether, while blood film examination may wrongly identify the species as Plasmodium malariae or P falciparum. Third-generation PCR assays can be used to reliably identify P knowlesi. PMID:23608876

  3. Plasmodium simium/Plasmodium vivax infections in southern brown howler monkeys from the Atlantic Forest

    PubMed Central

    Costa, Daniela Camargos; da Cunha, Vanessa Pecini; de Assis, Gabriela Maria Pereira; de Souza, Júlio César; Hirano, Zelinda Maria Braga; de Arruda, Mércia Eliane; Kano, Flora Satiko; Carvalho, Luzia Helena; de Brito, Cristiana Ferreira Alves

    2014-01-01

    Blood infection by the simian parasite, Plasmodium simium, was identified in captive (n = 45, 4.4%) and in wild Alouatta clamitans monkeys (n = 20, 35%) from the Atlantic Forest of southern Brazil. A single malaria infection was symptomatic and the monkey presented clinical and haematological alterations. A high frequency of Plasmodium vivax-specific antibodies was detected among these monkeys, with 87% of the monkeys testing positive against P. vivax antigens. These findings highlight the possibility of malaria as a zoonosis in the remaining Atlantic Forest and its impact on the epidemiology of the disease. PMID:25099335

  4. Plasmodium simium/Plasmodium vivax infections in southern brown howler monkeys from the Atlantic Forest.

    PubMed

    Costa, Daniela Camargos; da Cunha, Vanessa Pecini; de Assis, Gabriela Maria Pereira; de Souza Junior, Júlio César; Hirano, Zelinda Maria Braga; de Arruda, Mércia Eliane; Kano, Flora Satiko; Carvalho, Luzia Helena; de Brito, Cristiana Ferreira Alves

    2014-08-01

    Blood infection by the simian parasite, Plasmodium simium, was identified in captive (n = 45, 4.4%) and in wild Alouatta clamitans monkeys (n = 20, 35%) from the Atlantic Forest of southern Brazil. A single malaria infection was symptomatic and the monkey presented clinical and haematological alterations. A high frequency of Plasmodium vivax-specific antibodies was detected among these monkeys, with 87% of the monkeys testing positive against P. vivax antigens. These findings highlight the possibility of malaria as a zoonosis in the remaining Atlantic Forest and its impact on the epidemiology of the disease.

  5. Evidence for differences in erythrocyte surface receptors for the malarial parasites, Plasmodium falciparum and Plasmodium knowlesi

    PubMed Central

    1977-01-01

    Human erythrocytes lacking various blood group determinants were susceptible to invasion by Plasmodium falciparum including Duffy- negative erythrocytes that are refractory to invasion by Plasmodium knowlesi. Erythrocytes treated with trypsin or neuraminidase had reduced susceptibility of P. falciparum and normal susceptibility to P. knowlesi. Chymotrypsin treatment (0.1 mg/ml) blocked invasion only by P. knowlesi. The differential effect of enzymatic cleavage of determinats from the erythrocyte surface on invasion by these parasites suggests that P. falciparum and P. knowlesi interact with different determinants on the erythrocyte surface. PMID:327014

  6. First Full Draft Genome Sequence of Plasmodium brasilianum

    PubMed Central

    Ravishankar, Shashidhar; Nayak, Vishal; Patel, Dhruviben S.; Olsen, Christian; Sheth, Mili; Batra, Dhwani; Loparev, Vladimir; Vannberg, Fredrik O.; Udhayakumar, Venkatachalam; Barnwell, John W.

    2017-01-01

    ABSTRACT Plasmodium malariae is a protozoan parasite that can cause human malaria. The simian parasite Plasmodium brasilianum infects New World monkeys from Latin America and is morphologically indistinguishable from P. malariae. Here, we report the first full draft genome sequence for P. brasilianum. PMID:28183758

  7. Construction of living cellular automata using the Physarum plasmodium

    NASA Astrophysics Data System (ADS)

    Shirakawa, Tomohiro; Sato, Hiroshi; Ishiguro, Shinji

    2015-04-01

    The plasmodium of Physarum polycephalum is a unicellular and multinuclear giant amoeba that has an amorphous cell body. To clearly observe how the plasmodium makes decisions in its motile and exploratory behaviours, we developed a new experimental system to pseudo-discretize the motility of the organism. In our experimental space that has agar surfaces arranged in a two-dimensional lattice, the continuous and omnidirectional movement of the plasmodium was limited to the stepwise one, and the direction of the locomotion was also limited to four neighbours. In such an experimental system, a cellular automata-like system was constructed using the living cell. We further analysed the exploratory behaviours of the plasmodium by duplicating the experimental results in the simulation models of cellular automata. As a result, it was revealed that the behaviours of the plasmodium are not reproduced by only local state transition rules; and for the reproduction, a kind of historical rule setting is needed.

  8. Mitosis in the Human Malaria Parasite Plasmodium falciparum ▿

    PubMed Central

    Gerald, Noel; Mahajan, Babita; Kumar, Sanjai

    2011-01-01

    Malaria is caused by intraerythrocytic protozoan parasites belonging to Plasmodium spp. (phylum Apicomplexa) that produce significant morbidity and mortality, mostly in developing countries. Plasmodium parasites have a complex life cycle that includes multiple stages in anopheline mosquito vectors and vertebrate hosts. During the life cycle, the parasites undergo several cycles of extreme population growth within a brief span, and this is critical for their continued transmission and a contributing factor for their pathogenesis in the host. As with other eukaryotes, successful mitosis is an essential requirement for Plasmodium reproduction; however, some aspects of Plasmodium mitosis are quite distinct and not fully understood. In this review, we will discuss the current understanding of the architecture and key events of mitosis in Plasmodium falciparum and related parasites and compare them with the traditional mitotic events described for other eukaryotes. PMID:21317311

  9. Response to various periods of mechanical stimuli in Physarum plasmodium

    NASA Astrophysics Data System (ADS)

    Umedachi, Takuya; Ito, Kentaro; Kobayashi, Ryo; Ishiguro, Akio; Nakagaki, Toshiyuki

    2017-06-01

    Response to mechanical stimuli is a fundamental and critical ability for living cells to survive in hazardous conditions or to form adaptive and functional structures against force(s) from the environment. Although this ability has been extensively studied by molecular biology strategies, it is also important to investigate the ability from the viewpoint of biological rhythm phenomena so as to reveal the mechanisms that underlie these phenomena. Here, we use the plasmodium of the true slime mold Physarum polycephalum as the experimental system for investigating this ability. The plasmodium was repetitively stretched for various periods during which its locomotion speed was observed. Since the plasmodium has inherent oscillation cycles of protoplasmic streaming and thickness variation, how the plasmodium responds to various periods of external stretching stimuli can shed light on the other biological rhythm phenomena. The experimental results show that the plasmodium exhibits response to periodic mechanical stimulation and changes its locomotion speed depending on the period of the stretching stimuli.

  10. In silico comparative genome analysis of malaria parasite Plasmodium falciparum and Plasmodium vivax chromosome 4.

    PubMed

    Taherian Fard, Atefeh; Salman, Amna; Kazemi, Bahram; Bokhari, Habib

    2009-06-01

    Malarial parasite has long been a subject of research for a large community of scientists and has yet to be conquered. One of the main obstacles to effectively control this disease is rapidly evolving genetic structure of Plasmodium parasite itself. In this study, we focused on chromosome 4 of the Plasmodium falciparum and Plasmodium vivax species and carried out comparative studies of genes that are responsible for antigenic variation in respective species. Comparative analysis of genes responsible for antigenic variation (var and vir genes in P. falciparum and P. vivax, respectively) showed significant difference in their respective nucleotide sequence lengths as well as amino acid composition. The possible association of exon's length on pathogenecity of respective Plasmodium species was also investigated, and analysis of gene structure showed that on the whole, exon lengths in P. falciparum are larger compared to P. vivax. Analysis of tandem repeats across the genome has shown that the size of repetitive sequences has a direct effect on chromosomes length, which can also be a potential reason for P. falciparum's greater variability and hence pathogenecity than P. vivax.

  11. Simple Molecular Methods for Early Detection of Chloroquine Drug Resistance in Plasmodium vivax and Plasmodium falciparum.

    PubMed

    Singh, Gurjeet; Singh, Raksha; Urhehar, Anant Dattatraya

    2016-07-01

    Malaria is a human disease of which causes high morbidity and mortality. In Plasmodium falciparum malaria, the resistance to antimalarial drugs, especially chloroquine (CQ) is one of the paramount factors contributing to the global increase in morbidity and mortality, due to malaria. Hence, there is a need for detection of chloroquine drug resistance genes i.e., pfcrt-o (Plasmodium falciparum chloroquine resistance transporter-o) and pfmdr-1 (Plasmodium falciparum multidrug resistance-1) of P. falciparum and pvcrt-o (Plasmodium vivax chloroquine resistance transporter-o) and pvmdr-1 (Plasmodium vivax multidrug resistance-1) of P. vivax by using molecular methods to prevent mortality in malarial cases. To standardize chloroquine drug sensitivity testing by molecular method so as to provide reports of chloroquine within 6-8 hours to physicians for better treatment. This study was conducted over a period of one year from January to December 2014. A Total of 300 blood samples were collected from malaria suspected patient attending MGM Hospital, Kamothe, Navi Mumbai, India. Out of 300 blood samples, 44 were malaria positive as assessed by Thick and Thin blood smear stained, by Leishman's method and examination with light microscope. Chloroquine drug sensitivity testing was performed using WHO III plate method (micro test). Nested PCR was done for detection of pfcrt-o and pfmdr-1 for P. falciparum and pvcrt-o, pvmdr-1 genes for P. vivax. Total 44 samples were included in this study, out of which 22 samples confirmed for Plasmodium falciparum and 22 samples confirmed for Plasmodium vivax. Out of 22 P. falciparum 15 (68.18%) samples were chloroquine resistant. P. vivax showed chloroquine resistance to 5 samples (22.73%) by method similar to WHO III plate method (micro test) and nested PCR. Drug resistance testing by molecular methods is useful for early detection of antimalarial drug resistance. pfmdr-1 along with pfcrt-o can be used as biomarker for chloroquine drug

  12. Laser-induced inactivation of Plasmodium falciparum

    PubMed Central

    2012-01-01

    Background Haemozoin crystals, produced by Plasmodium during its intra-erythrocytic asexual reproduction cycle, can generate UV light via the laser-induced, non-linear optical process of third harmonic generation (THG). In the current study the feasibility of using haemozoin, constitutively stored in the parasite’s food vacuole, to kill the parasite by irradiation with a near IR laser was evaluated. Methods Cultured Plasmodium parasites at different stages of development were irradiated with a pulsed NIR laser and the viability of parasites at each stage was evaluated from their corresponding growth curves using the continuous culture method. Additional testing for germicidal effects of haemozoin and NIR laser was performed by adding synthetic haemozoin crystals to Escherichia coli in suspension. Cell suspensions were then irradiated with the laser and small aliquots taken and spread on agar plates containing selective agents to determine cell viability (CFU). Results Parasites in the late-trophozoites form as well as trophozoites in early-stage of DNA synthesis were found to be the most sensitive to the treatment with ~4-log reduction in viability after six passes through the laser beam; followed by parasites in ring phase (~2-log reduction). A ~1-log reduction in E. coli viability was obtained following a 60 min irradiation regimen of the bacteria in the presence of 1 μM synthetic haemozoin and a ~2-log reduction in the presence of 10 μM haemozoin. Minimal (≤15%) cell kill was observed in the presence of 10 μM haemin. Conclusions Laser-induced third-harmonic generation by haemozoin can be used to inactivate Plasmodium. This result may have clinical implications for treating severe malaria symptoms by irradiating the patient’s blood through the skin or through dialysis tubing with a NIR laser. PMID:22873646

  13. No Evidence for Ape Plasmodium Infections in Humans in Gabon

    PubMed Central

    Ollomo, Benjamin; Arnathau, Céline; Roche, Benjamin; Elguero, Eric; Moukodoum, Nancy Diamella; Okougha, Alain-Prince; Mve Ondo, Bertrand; Boundenga, Larson; Houzé, Sandrine; Galan, Maxime; Nkoghé, Dieudonné; Leroy, Eric M.; Durand, Patrick; Paupy, Christophe; Renaud, François; Prugnolle, Franck

    2015-01-01

    African great apes are naturally infected by a multitude of Plasmodium species most of them recently discovered, among which several are closely related to human malaria agents. However, it is still unknown whether these animals can serve as source of infections for humans living in their vicinity. To evaluate this possibility, we analysed the nature of Plasmodium infections from a bank of 4281 human blood samples collected in 210 villages of Gabon, Central Africa. Among them, 2255 were detected positive to Plasmodium using molecular methods (Plasmodium Cytochrome b amplification). A high throughput sequencing technology (454 GS-FLX Titanium technology, Roche) was then used to identify the Plasmodium species present within each positive sample. Overall, we identified with confidence only three species infecting humans in Gabon: P. falciparum, P. malariae and P. ovale. None of the species known to infect non-human primates in Central Africa was found. Our study shows that ape Plasmodium parasites of the subgenus Laverania do not constitute a frequent source of infection for humans. It also suggests that some strong host genetic barriers must exist to prevent the cross species transmission of ape Plasmodium in a context of ever increasing contacts between humans and wildlife. PMID:26039338

  14. No evidence for ape Plasmodium infections in humans in Gabon.

    PubMed

    Délicat-Loembet, Lucresse; Rougeron, Virginie; Ollomo, Benjamin; Arnathau, Céline; Roche, Benjamin; Elguero, Eric; Moukodoum, Nancy Diamella; Okougha, Alain-Prince; Mve Ondo, Bertrand; Boundenga, Larson; Houzé, Sandrine; Galan, Maxime; Nkoghé, Dieudonné; Leroy, Eric M; Durand, Patrick; Paupy, Christophe; Renaud, François; Prugnolle, Franck

    2015-01-01

    African great apes are naturally infected by a multitude of Plasmodium species most of them recently discovered, among which several are closely related to human malaria agents. However, it is still unknown whether these animals can serve as source of infections for humans living in their vicinity. To evaluate this possibility, we analysed the nature of Plasmodium infections from a bank of 4281 human blood samples collected in 210 villages of Gabon, Central Africa. Among them, 2255 were detected positive to Plasmodium using molecular methods (Plasmodium Cytochrome b amplification). A high throughput sequencing technology (454 GS-FLX Titanium technology, Roche) was then used to identify the Plasmodium species present within each positive sample. Overall, we identified with confidence only three species infecting humans in Gabon: P. falciparum, P. malariae and P. ovale. None of the species known to infect non-human primates in Central Africa was found. Our study shows that ape Plasmodium parasites of the subgenus Laverania do not constitute a frequent source of infection for humans. It also suggests that some strong host genetic barriers must exist to prevent the cross species transmission of ape Plasmodium in a context of ever increasing contacts between humans and wildlife.

  15. Prevalence and distribution of human Plasmodium infection in Pakistan.

    PubMed

    Khattak, Aamer A; Venkatesan, Meera; Nadeem, Muhammad F; Satti, Humayoon S; Yaqoob, Adnan; Strauss, Kathy; Khatoon, Lubna; Malik, Salman A; Plowe, Christopher V

    2013-08-28

    Both Plasmodium vivax and Plasmodium falciparum are prevalent in Pakistan, yet up-to-date data on the epidemiology of malaria in Pakistan are not available. This study was undertaken to determine the current prevalence and distribution of Plasmodium species across the country. A malariometric population survey was conducted in 2011 using blood samples collected from 801 febrile patients of all ages in four provinces and the capital city of Islamabad. Microscopically confirmed Plasmodium-positive blood samples were reconfirmed by polymerase chain reaction (PCR). Confirmed parasite-positive samples were subjected to species-specific PCR capable of detecting four species of human malaria. Of the 707 PCR-positive samples, 128 (18%) were P. falciparum, 536 (76%) were P. vivax, and 43 (6%) were mixed P. falciparum and P. vivax. Ninety-four microscopy-positive samples were PCR-negative, and Plasmodium malariae and Plasmodium ovale were not detected. Prevalence of P. vivax ranged from 2.4% in Punjab Province to 10.8% in Sindh Province and prevalence of P. falciparum ranged from 0.1% in Islamabad to 3.8% in Balochistan. Plasmodium infections in Pakistan are largely attributed to P. vivax but P. falciparum and mixed species infections are also prevalent. In addition, regional variation in the prevalence and species composition of malaria is high.

  16. Prevalence and distribution of human Plasmodium infection in Pakistan

    PubMed Central

    2013-01-01

    Background Both Plasmodium vivax and Plasmodium falciparum are prevalent in Pakistan, yet up-to-date data on the epidemiology of malaria in Pakistan are not available. This study was undertaken to determine the current prevalence and distribution of Plasmodium species across the country. Methods A malariometric population survey was conducted in 2011 using blood samples collected from 801 febrile patients of all ages in four provinces and the capital city of Islamabad. Microscopically confirmed Plasmodium-positive blood samples were reconfirmed by polymerase chain reaction (PCR). Confirmed parasite-positive samples were subjected to species-specific PCR capable of detecting four species of human malaria. Results Of the 707 PCR-positive samples, 128 (18%) were P. falciparum, 536 (76%) were P. vivax, and 43 (6%) were mixed P. falciparum and P. vivax. Ninety-four microscopy-positive samples were PCR-negative, and Plasmodium malariae and Plasmodium ovale were not detected. Prevalence of P. vivax ranged from 2.4% in Punjab Province to 10.8% in Sindh Province and prevalence of P. falciparum ranged from 0.1% in Islamabad to 3.8% in Balochistan. Conclusions Plasmodium infections in Pakistan are largely attributed to P. vivax but P. falciparum and mixed species infections are also prevalent. In addition, regional variation in the prevalence and species composition of malaria is high. PMID:23984968

  17. Plasmodium infection decreases fecundity and increases survival of mosquitoes.

    PubMed

    Vézilier, J; Nicot, A; Gandon, S; Rivero, A

    2012-10-07

    Long-lived mosquitoes maximize the chances of Plasmodium transmission. Yet, in spite of decades of research, the effect of Plasmodium parasites on mosquito longevity remains highly controversial. On the one hand, many studies report shorter lifespans in infected mosquitoes. On the other hand, parallel (but separate) studies show that Plasmodium reduces fecundity and imply that this is an adaptive strategy of the parasite aimed at redirecting resources towards longevity. No study till date has, however, investigated fecundity and longevity in the same individuals to see whether this prediction holds. In this study, we follow for both fecundity and longevity in Plasmodium-infected and uninfected mosquitoes using a novel, albeit natural, experimental system. We also explore whether the genetic variations that arise through the evolution of insecticide resistance modulate the effect of Plasmodium on these two life-history traits. We show that (i) a reduction in fecundity in Plasmodium-infected mosquitoes is accompanied by an increase in longevity; (ii) this increase in longevity arises through a trade-off between reproduction and survival; and (iii) in insecticide-resistant mosquitoes, the slope of this trade-off is steeper when the mosquito is infected by Plasmodium (cost of insecticide resistance).

  18. Human Infections and Detection of Plasmodium knowlesi

    PubMed Central

    Daneshvar, Cyrus

    2013-01-01

    SUMMARY Plasmodium knowlesi is a malaria parasite that is found in nature in long-tailed and pig-tailed macaques. Naturally acquired human infections were thought to be extremely rare until a large focus of human infections was reported in 2004 in Sarawak, Malaysian Borneo. Human infections have since been described throughout Southeast Asia, and P. knowlesi is now recognized as the fifth species of Plasmodium causing malaria in humans. The molecular, entomological, and epidemiological data indicate that human infections with P. knowlesi are not newly emergent and that knowlesi malaria is primarily a zoonosis. Human infections were undiagnosed until molecular detection methods that could distinguish P. knowlesi from the morphologically similar human malaria parasite P. malariae became available. P. knowlesi infections cause a spectrum of disease and are potentially fatal, but if detected early enough, infections in humans are readily treatable. In this review on knowlesi malaria, we describe the early studies on P. knowlesi and focus on the epidemiology, diagnosis, clinical aspects, and treatment of knowlesi malaria. We also discuss the gaps in our knowledge and the challenges that lie ahead in studying the epidemiology and pathogenesis of knowlesi malaria and in the prevention and control of this zoonotic infection. PMID:23554413

  19. Human infections and detection of Plasmodium knowlesi.

    PubMed

    Singh, Balbir; Daneshvar, Cyrus

    2013-04-01

    Plasmodium knowlesi is a malaria parasite that is found in nature in long-tailed and pig-tailed macaques. Naturally acquired human infections were thought to be extremely rare until a large focus of human infections was reported in 2004 in Sarawak, Malaysian Borneo. Human infections have since been described throughout Southeast Asia, and P. knowlesi is now recognized as the fifth species of Plasmodium causing malaria in humans. The molecular, entomological, and epidemiological data indicate that human infections with P. knowlesi are not newly emergent and that knowlesi malaria is primarily a zoonosis. Human infections were undiagnosed until molecular detection methods that could distinguish P. knowlesi from the morphologically similar human malaria parasite P. malariae became available. P. knowlesi infections cause a spectrum of disease and are potentially fatal, but if detected early enough, infections in humans are readily treatable. In this review on knowlesi malaria, we describe the early studies on P. knowlesi and focus on the epidemiology, diagnosis, clinical aspects, and treatment of knowlesi malaria. We also discuss the gaps in our knowledge and the challenges that lie ahead in studying the epidemiology and pathogenesis of knowlesi malaria and in the prevention and control of this zoonotic infection.

  20. Severe Plasmodium knowlesi with dengue coinfection.

    PubMed

    Che Rahim, Mohd Jazman; Mohammad, Nurashikin; Besari, Alwi Muhd; Wan Ghazali, Wan Syamimee

    2017-02-20

    We report a case of severe Plasmodium knowlesi and dengue coinfection in a previously healthy 59-year-old Malay man who presented with worsening shortness of breath, high-grade fever with chills and rigors, dry cough, myalgia, arthralgia, chest discomfort and poor appetite of 1 week duration. There was a history mosquito fogging around his neighbourhood in his hometown. Further history revealed that he went to a forest in Jeli (northern part of Kelantan) 3 weeks prior to the event. Initially he was treated as severe dengue with plasma leakage complicated with type 1 respiratory failure as evidenced by positive serum NS1-antigen and thrombocytopenia. Blood for malarial parasite (BFMP) was sent for test as there was suspicion of malaria due to persistent thrombocytopenia despite recovering from dengue infection and the presence of a risk factor. The test revealed high count of malaria parasite. Confirmatory PCR identified the parasite to be Plasmodium knowlesi Intravenous artesunate was administered to the patient immediately after acquiring the BFMP result. Severe malaria was complicated with acute kidney injury and septicaemic shock. Fortunately the patient made full recovery and was discharged from the ward after 2 weeks of hospitalisation. 2017 BMJ Publishing Group Ltd.

  1. Management of relapsing Plasmodium vivax malaria

    PubMed Central

    Chu, Cindy S; White, Nicholas J

    2016-01-01

    ABSTRACT Introduction: Relapses are important contributors to illness and morbidity in Plasmodium vivax and P. ovale infections. Relapse prevention (radical cure) with primaquine is required for optimal management, control and ultimately elimination of Plasmodium vivax malaria. A review was conducted with publications in English, French, Portuguese and Spanish using the search terms ‘P. vivax’ and ‘relapse’. Areas covered: Hypnozoites causing relapses may be activated weeks or months after initial infection. Incidence and temporal patterns of relapse varies geographically. Relapses derive from parasites either genetically similar or different from the primary infection indicating that some derive from previous infections. Malaria illness itself may activate relapse. Primaquine is the only widely available treatment for radical cure. However, it is often not given because of uncertainty over the risks of primaquine induced haemolysis when G6PD deficiency testing is unavailable. Recommended dosing of primaquine for radical cure in East Asia and Oceania is 0.5 mg base/kg/day and elsewhere is 0.25 mg base/kg/day. Alternative treatments are under investigation. Expert commentary: Geographic heterogeneity in relapse patterns and chloroquine susceptibility of P. vivax, and G6PD deficiency epidemiology mean that radical treatment should be given much more than it is today. G6PD testing should be made widely available so primaquine can be given more safely. PMID:27530139

  2. Artemisinins target the SERCA of Plasmodium falciparum.

    PubMed

    Eckstein-Ludwig, U; Webb, R J; Van Goethem, I D A; East, J M; Lee, A G; Kimura, M; O'Neill, P M; Bray, P G; Ward, S A; Krishna, S

    2003-08-21

    Artemisinins are extracted from sweet wormwood (Artemisia annua) and are the most potent antimalarials available, rapidly killing all asexual stages of Plasmodium falciparum. Artemisinins are sesquiterpene lactones widely used to treat multidrug-resistant malaria, a disease that annually claims 1 million lives. Despite extensive clinical and laboratory experience their molecular target is not yet identified. Activated artemisinins form adducts with a variety of biological macromolecules, including haem, translationally controlled tumour protein (TCTP) and other higher-molecular-weight proteins. Here we show that artemisinins, but not quinine or chloroquine, inhibit the SERCA orthologue (PfATP6) of Plasmodium falciparum in Xenopus oocytes with similar potency to thapsigargin (another sesquiterpene lactone and highly specific SERCA inhibitor). As predicted, thapsigargin also antagonizes the parasiticidal activity of artemisinin. Desoxyartemisinin lacks an endoperoxide bridge and is ineffective both as an inhibitor of PfATP6 and as an antimalarial. Chelation of iron by desferrioxamine abrogates the antiparasitic activity of artemisinins and correspondingly attenuates inhibition of PfATP6. Imaging of parasites with BODIPY-thapsigargin labels the cytosolic compartment and is competed by artemisinin. Fluorescent artemisinin labels parasites similarly and irreversibly in an Fe2+-dependent manner. These data provide compelling evidence that artemisinins act by inhibiting PfATP6 outside the food vacuole after activation by iron.

  3. Plasmodium vivax malaria during pregnancy, Bolivia.

    PubMed

    Brutus, Laurent; Santalla, José; Schneider, Dominique; Avila, Juan Carlos; Deloron, Philippe

    2013-10-01

    Plasmodium vivax is a major cause of illness in areas with low transmission of malaria in Latin America, Asia, and the Horn of Africa. However, pregnancy-associated malaria remains poorly characterized in such areas. Using a hospital-based survey of women giving birth and an antenatal survey, we assessed the prevalence rates of Plasmodium spp. infections in pregnant women in Bolivia, and evaluated the consequences of malaria during pregnancy on the health of mothers and newborns. P. vivax infection was detected in 7.9% of pregnant women attending antenatal visits, and placental infection occurred in 2.8% of deliveries; these rates did not vary with parity. Forty-two percent of all P. vivax malaria episodes were symptomatic. P. vivax-infected pregnant women were frequently anemic (6.5%) and delivered babies of reduced birthweight. P. vivax infections during pregnancy are clearly associated with serious adverse outcomes and should be considered in prevention strategies of pregnancy-associated malaria.

  4. Plasmodium falciparum full life cycle and Plasmodium ovale liver stages in humanized mice

    PubMed Central

    Soulard, Valérie; Bosson-Vanga, Henriette; Lorthiois, Audrey; Roucher, Clémentine; Franetich, Jean- François; Zanghi, Gigliola; Bordessoulles, Mallaury; Tefit, Maurel; Thellier, Marc; Morosan, Serban; Le Naour, Gilles; Capron, Frédérique; Suemizu, Hiroshi; Snounou, Georges; Moreno-Sabater, Alicia; Mazier, Dominique

    2015-01-01

    Experimental studies of Plasmodium parasites that infect humans are restricted by their host specificity. Humanized mice offer a means to overcome this and further provide the opportunity to observe the parasites in vivo. Here we improve on previous protocols to achieve efficient double engraftment of TK-NOG mice by human primary hepatocytes and red blood cells. Thus, we obtain the complete hepatic development of P. falciparum, the transition to the erythrocytic stages, their subsequent multiplication, and the appearance of mature gametocytes over an extended period of observation. Furthermore, using sporozoites derived from two P. ovale-infected patients, we show that human hepatocytes engrafted in TK-NOG mice sustain maturation of the liver stages, and the presence of late-developing schizonts indicate the eventual activation of quiescent parasites. Thus, TK-NOG mice are highly suited for in vivo observations on the Plasmodium species of humans. PMID:26205537

  5. BLOOD-STAGE DYNAMICS AND CLINICAL IMPLICATIONS OF MIXED PLASMODIUM VIVAX–PLASMODIUM FALCIPARUM INFECTIONS

    PubMed Central

    MASON, DANIEL P.; McKENZIE, F. ELLIS

    2008-01-01

    We present a mathematical model of the blood-stage dynamics of mixed Plasmodium vivax–Plasmodium falciparum malaria infections in humans. The model reproduces features of such infections found in nature and suggests several phenomena that may merit clinical attention, including the potential recrudescence of a long-standing, low-level P. falciparum infection following a P. vivax infection or relapse and the capacity of an existing P. vivax infection to reduce the peak parasitemia of a P. falciparum superinfection. We simulate the administration of anti-malarial drugs, and illustrate some potential complications in treating mixed-species malaria infections. Notably, our model indicates that when a mixed-species infection is misdiagnosed as a single-species P. vivax infection, treatment for P. vivax can lead to a surge in P. falciparum parasitemia. PMID:10497972

  6. Plasmodium berghei bio-burden correlates with parasite lactate dehydrogenase: application to murine Plasmodium diagnostics.

    PubMed

    De, Sai Lata; Stanisic, Danielle I; Rivera, Fabian; Batzloff, Michael R; Engwerda, Christian; Good, Michael F

    2016-01-04

    The spectrum of techniques to detect malaria parasites in whole blood is limited to measuring parasites in circulation. One approach that is currently used to enumerate total parasite bio-burden involves the use of bio-luminescent parasites. As an alternative approach, this study describes the use of a commercial ELISA human parasite lactate dehydrogenase (pLDH) detection kit to estimate total parasite bio-burden in murine malaria models. The cross reactivity of pLDH in a commercial human malaria pLDH diagnostic kit was established in different components of blood for different murine malaria models. The use of pLDH as a measure of parasite bio-burden was evaluated by examining pLDH in relation to peripheral blood parasitaemia as determined by microscopy and calculating total parasite bio-burden using a bio-luminescent Plasmodium berghei ANKA luciferase parasite. The pLDH antigen was detected in all four murine Plasmodium species and in all components of Plasmodium-infected blood. A significant correlation (r = 0.6922, P value <0.0001) was observed between total parasite bio-burden, measured as log average radiance, and concentration of pLDH units. This high throughput assay is a suitable measure of total parasite bio-burden in murine malaria infections. Unlike existing methods, it permits the estimation of both circulating and sequestered parasites, allowing a more accurate assessment of parasite bio-burden.

  7. Immunization of mice with Plasmodium TCTP delays establishment of Plasmodium infection.

    PubMed

    Taylor, K J; Van, T T H; MacDonald, S M; Meshnick, S R; Fernley, R T; Macreadie, I G; Smooker, P M

    2015-01-01

    Translationally controlled tumour protein (TCTP) may play an important role in the establishment or maintenance of parasitemia in a malarial infection. In this study, the potential of TCTP as a malaria vaccine was investigated in two trials. In the initial vaccine trial, Plasmodium falciparum TCTP (PfTCTP) was expressed in Saccharomyces cerevisiae and used to immunize BALB/c mice. Following challenge with Plasmodium yoelii YM, parasitemia was significantly reduced during the early stages of infection. In the second vaccine trial, the TCTP from P. yoelii and P. berghei was expressed in Escherichia coli and used in several mouse malaria models. A significant reduction in parasitemia in the early stages of infection was observed in BALB/c mice challenged with P. yoelii YM. A significantly reduced parasitemia at each day leading up to a delayed and reduced peak parasitemia was also observed in BALB/c mice challenged with the nonlethal Plasmodium chabaudi (P.c.) chabaudi AS. These results suggest that TCTP has an important role for parasite establishment and may be important for pathogenesis.

  8. Plasmodium infection in a Leadbeater's possum (Gymnobelideus leadbeateri).

    PubMed

    Scheelings, T F; McLaren, P J; Tatarczuch, L; Slocombe, R F

    2016-08-01

    A wild-caught, adult female Leadbeater's possum (Gymnobelideus leadbeateri) died while in captivity after suffering from chronic ill-thrift that progressed to acute respiratory distress. On histopathological examination of tissues, the cause of death was determined to be severe acute pneumonia with pulmonary oedema associated with an intracellular protozoan parasite present within erythrocytes. Transmission electron microscopy was performed on lung tissues and organisms consistent for Plasmodium sp. were identified within numerous erythrocytes. Molecular characterisation of the parasite from DNA extracted from tissue blocks of fixed lung determined the organism to belong to the genus Plasmodium (100% similarity to Plasmodium species when a BLAST analysis was performed); however, speciation of the organism was not possible. This is the first report of Plasmodium sp. infection and subsequent disease in a native Australian mammal. The lifecycle of this parasite remains unknown. It is also unknown what effects haemoparasitism may have on the population dynamics of this endangered possum species. © 2016 Australian Veterinary Association.

  9. Colombian Anopheles triannulatus (Diptera: Culicidae) Naturally Infected with Plasmodium spp.

    PubMed Central

    Rosero, Doris A.; Naranjo-Diaz, Nelson; Alvarez, Natalí; Cienfuegos, Astrid V.; Luckhart, Shirley

    2013-01-01

    The role of Anopheles triannulatus as a local vector has not yet been defined for malaria-endemic regions of Colombia. Therefore, the aim of this work was to detect An. triannulatus naturally infected with Plasmodium spp., as an approximation to determining its importance as malaria vector in the country. A total of 510 An. triannulatus were collected in six malaria-endemic localities of NW and SE Colombia from January 2009 to March 2011. In the NW, two specimens were naturally infected; one with Plasmodium vivax VK247, collected biting on humans and the other with Plasmodium falciparum, collected resting on cattle. In the SE, two specimens were positive for P. falciparum. Although these results show An. triannulatus naturally infected with Plasmodium, further studies are recommended to demonstrate the epidemiological importance of this species in malaria-endemic regions of Colombia. PMID:27335865

  10. Placental histopathological changes associated with Plasmodium vivax infection during pregnancy.

    PubMed

    Souza, Rodrigo M; Ataíde, Ricardo; Dombrowski, Jamille G; Ippólito, Vanessa; Aitken, Elizabeth H; Valle, Suiane N; Álvarez, José M; Epiphanio, Sabrina; Epiphânio, Sabrina; Marinho, Claudio R F

    2013-01-01

    Histological evidence of Plasmodium in the placenta is indicative of placental malaria, a condition associated with severe outcomes for mother and child. Histological lesions found in placentas from Plasmodium-exposed women include syncytial knotting, syncytial rupture, thickening of the placental barrier, necrosis of villous tissue and intervillositis. These histological changes have been associated with P. falciparum infections, but little is known about the contribution of P. vivax to such changes. We conducted a cross-sectional study with pregnant women at delivery and assigned them to three groups according to their Plasmodium exposure during pregnancy: no Plasmodium exposure (n = 41), P. vivax exposure (n = 59) or P. falciparum exposure (n = 19). We evaluated their placentas for signs of Plasmodium and placental lesions using ten histological parameters: syncytial knotting, syncytial rupture, placental barrier thickness, villi necrosis, intervillous space area, intervillous leucocytes, intervillous mononucleates, intervillous polymorphonucleates, parasitized erythrocytes and hemozoin. Placentas from P. vivax-exposed women showed little evidence of Plasmodium or hemozoin but still exhibited more lesions than placentas from women not exposed to Plasmodium, especially when infections occurred twice or more during pregnancy. In the Brazilian state of Acre, where diagnosis and primary treatment are readily available and placental lesions occur in the absence of detected placental parasites, relying on the presence of Plasmodium in the placenta to evaluate Plasmodium-induced placental pathology is not feasible. Multivariate logistic analysis revealed that syncytial knotting (odds ratio [OR], 4.21, P = 0.045), placental barrier thickness (OR, 25.59, P = 0.021) and mononuclear cells (OR, 4.02, P = 0.046) were increased in placentas from P. vivax-exposed women when compared to women not exposed to Plasmodium during pregnancy. A vivax-score was

  11. Seroepidemiology of Plasmodium species infections in Zimbabwean population.

    PubMed

    Amanfo, Seth A; Mduluza, Takafira; Midzi, Nicholas; Cavanagh, David R; Mutapi, Francisca

    2016-05-10

    Individuals living in malaria-endemic regions may be exposed to more than one Plasmodium species; there is paucity of data on the distribution of the different species of Plasmodium in affected populations, in part due to the diagnostic method of microscopy, which cannot easily differentiate between the species. Sero-epidemiological data can overcome some of the shortcomings of microscopy. The specificity of IgG antibodies to recombinant merozoite surface protein 1 (MSP-119) derived from four human Plasmodium species (Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, Plasmodium ovale) was investigated using competition enzyme-linked immunosorbent assay. Subsequently, these antigens were used to determine the exposure prevalence to the different Plasmodium species in serum samples of participants. One-hundred individuals, aged five-18 years, from each of the three Plasmodium meso-endemic Zimbabwean villages (Burma Valley, Mutoko, Chiredzi) were recruited in the study. The study demonstrated that the host serum reactivity to MSP-119 antigens was species-specific and that no cross-reactivity occurred. The overall prevalence of antibody response to MSP-119 antigens was 61 % in Burma Valley, 31 % in Mutoko and 32 % in Chiredzi. Single species IgG responses to MSP-119 were most frequent against P. falciparum, followed by P. malariae and P. ovale, with responses to P. vivax being the least prevalent. Interestingly, 78-87 and 50 % of sera with IgG responses to P. malariae and P. ovale MSP-119, respectively, also had IgG specific response for P. falciparum MSP-119 antigens, indicating that exposure to these species is a common occurrence in these populations. Single species IgG responses to the non-falciparum species were at a very low frequency, ranging between 0 and 13 % for P. malariae. There is evidence of a higher exposure to the non-falciparum parasite species than previously reported in Zimbabwe. The recombinant MSP-119 antigens could be used as

  12. Drug Evaluation in the Plasmodium Falciparum - Aotus Model.

    DTIC Science & Technology

    1992-03-23

    AOTUS MODEL PRINCIPAL INVESTIGATOR: Richard N. Rossan, Ph.D. CONTRACTING ORGANIZATION: PROMED TRADING, S.A. P.O. Box 025426, PTY-051 Miami, Florida...91 - 2/28/92) 4. TITLE AND SUBTITLE S. FUNDING NUMBERS DRUG EVALUATION IN THE PLASMODIUM FALCIPARUM - Contract No. AOTUS MODEL DAMD17-91-C-1072 6C...words) Tne Panamanian Autus - PLasmodium falciparum model was used to evaluate potential antimalaria drugs. Neither protriptylene nor tetrandrine, each

  13. Drug Evaluation in the Plasmodium Falciparum - Aotus Model

    DTIC Science & Technology

    1993-03-23

    Rossan, RN, Harper, JS III, Davidson, DE Jr., Escajadillo , A. and Christensen, HA.1985. Comparison of Plasmodium falc1parum infections in Panamanian and...Malaria. Amsterdam. 6. Pollack, S, Rossan, RN, Davidson, DE, Escajadillo , A., 1987. Desferrioxamine suppresses Plasmodium falciparum in Aotus monkeys. Proc...Soc Expt Biol Med. 184:162-164.- 7. Panton, LJ, Rossan, RN, Escajadillo , A, Matsumoto, Y, Lee, AT, Labroo, VM, Kirk, KL, Cohen, LA, Airkawa, M, Howard

  14. Active and Passive Immunization against Plasmodium Yoelii Sporozoites

    DTIC Science & Technology

    1990-01-01

    reverse if necessary and identify by block number) FIELD GROUP SUB-GROUP malaria vaccine ; thiocyanate elution; Plasmodium yoelii; humoral immunity...G.H. Lowell1,4 R.L. Beaudoin,’ & S.L. Hoffman’ Three subunit vaccines based on the major repeat. (0GPGAP)n, and flanking iegions of the Plasmodium yoeui...with subunit vaccines containing OGPGAP but were not protected 9 :- .~v against challenge with 40-200 sporozoites. To determine if antibody avidity

  15. Using Click Chemistry to Identify Potential Drug Targets in Plasmodium

    DTIC Science & Technology

    2016-06-01

    AWARD NUMBER: W81XWH-13-1-0429 TITLE: Using "Click Chemistry " to Identify Potential Drug Targets in Plasmodium PRINCIPAL INVESTIGATOR...29Mar2016 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER W81XWH-13-1-0429 Using click chemistry to identify potential drug targets in Plasmodium 5b...Al-Tsp derivatives begins. Two classes of Tsp derivatives (Al-Tsp) are appropriate for click chemistry (Fig. 1). Class I derivatives carry a

  16. Plasmodium knowlesi infection imported to Germany, January 2013.

    PubMed

    Orth, H; Jensen, B O; Holtfreter, M C; Kocheril, S J; Mallach, S; MacKenzie, C; Müller-Stöver, I; Henrich, B; Imwong, M; White, N J; Häussinger, D; Richter, J

    2013-10-03

    Plasmodium knowlesi was known as a plasmodium of macaques until P. knowlesi transmission to humans was recognised in Borneo and later throughout South-East Asia. We describe here a case of a P. knowlesi infection imported to Germany from Thailand. The patient had not taken antimalarial chemoprophylaxis and suffered from daily fever attacks. Microscopy revealed trophozoites and gametocytes resembling P. malariae. P. knowlesi malaria was confirmed by PCR.

  17. Plasmodium vivax malaria associated with acute post infectious glomerulonephritis.

    PubMed

    Kanodia, Kamal V; Vanikar, Aruna V; Kute, Vivek Balkrishna; Trivedi, Hargovind L

    2013-08-01

    Malaria remains a major health problem in many parts of the world leading to high morbidity and mortality related to renal dysfunction and relapsing nature of Plasmodium vivax malaria. Acute renal failure occurs commonly in Plasmodium falciparum malaria, although its rare occurrences have been reported in P. vivax malaria also. We reported a rare case of P. vivax malaria monoinfection associated with acute post infectious glomerulonephritis.

  18. Using Click Chemistry to Identify Potential Drug Targets in Plasmodium

    DTIC Science & Technology

    2015-04-01

    mammalian cycle. Inhibiting this step can block malaria at an early step. However, few anti-malar ials target l iver infection by sporozo ites. Our...step of the Plasmodium mammalian cycle. Inhibiting this step can block malaria at an early step. However, few anti-malarials target liver infection...intrahepatic development 2. Keywords Plasmodium, sporozoites, liver infection, kinase, drugs, malaria 3. Accomplishments • What were the major

  19. C. elegans NIMA-related kinases NEKL-2 and NEKL-3 are required for the completion of molting.

    PubMed

    Yochem, John; Lažetić, Vladimir; Bell, Leslie; Chen, Lihsia; Fay, David

    2015-02-15

    Caenorhabditis elegans molting is a process during which the apical extracellular matrix of the epidermis, the cuticle, is remodeled through a process of degradation and re-synthesis. Using a genetic approach, we identified nekl-3 as essential for the completion of molting. NEKL-3 is highly similar to the mammalian NEK kinase family members NEK6 and NEK7. Animals homozygous for a hypomorphic mutation in nekl-3, sv3, had a novel molting defect in which the central body region, but not the head or tail, was unable to shed the old cuticle. In contrast, a null mutation in nekl-3, gk506, led to complete enclosure within the old cuticle. nekl-2, which is most similar to mammalian NEK8, was also essential for molting. Mosaic analyses demonstrated that NEKL-2 and NEKL-3 were specifically required within the large epidermal syncytium, hyp7, to facilitate molting. Consistent with this, NEKL-2 and NEKL-3 were expressed at the apical surface of hyp7 where they localized to small spheres or tubular structures. Inhibition of nekl-2, but not nekl-3, led to the mislocalization of LRP-1/megalin, a cell surface receptor for low-density lipoprotein (LDL)-binding proteins. In addition, nekl-2 inhibition led to the mislocalization of several other endosome-associated proteins. Notably, LRP-1 acts within hyp7 to facilitate completion of molting, suggesting at least one mechanism by which NEKL-2 may influence molting. Notably, our studies failed to reveal a requirement for NEKL-2 or NEKL-3 in cell division, a function reported for several mammalian NEKs including NEK6 and NEK7. Our findings provide the first genetic and in vivo evidence for a role of NEK family members in endocytosis, which may be evolutionarily conserved.

  20. Proteasome Inhibitors Block Development of Plasmodium spp.

    PubMed Central

    Gantt, Soren M.; Myung, Joon Mo; Briones, Marcelo R. S.; Li, Wei Dong; Corey, E. J.; Omura, Satoshi; Nussenzweig, Victor; Sinnis, Photini

    1998-01-01

    Proteasomes degrade most of the proteins inside eukaryotic cells, including transcription factors and regulators of cell cycle progression. Here we show that nanomolar concentrations of lactacystin, a specific irreversible inhibitor of the 20S proteasome, inhibit development of the exoerythrocytic and erythrocytic stages of the malaria parasite. Although lactacystin-treated Plasmodium berghei sporozoites are still invasive, their development into exoerythrocytic forms (EEF) is inhibited in vitro and in vivo. Erythrocytic schizogony of P. falciparum in vitro is also profoundly inhibited when drug treatment of the synchronized parasites is prior, but not subsequent, to the initiation of DNA synthesis, suggesting that the inhibitory effect of lactacystin is cell cycle specific. Lactacystin reduces P. berghei parasitemia in rats, but the therapeutic index is very low. Along with other studies showing that lactacystin inhibits stage-specific transformation in Trypanosoma and Entamoeba spp., these findings highlight the potential of proteasome inhibitors as drugs for the treatment of diseases caused by protozoan parasites. PMID:9756786

  1. Desferrioxamine suppresses Plasmodium falciparum in Aotus monkeys.

    PubMed

    Pollack, S; Rossan, R N; Davidson, D E; Escajadillo, A

    1987-02-01

    Clinical observation has suggested that iron deficiency may be protective in malaria, and we have found that desferrioxamine (DF), an iron-specific chelating agent, inhibited Plasmodium falciparum growth in vitro. It was difficult to be confident that DF would be effective in an intact animal, however, because continuous exposure to DF was required in vitro and, in vivo, DF is rapidly excreted. Also, the in vitro effect of DF was overcome by addition of iron to the culture and in vivo there are potentially high local iron concentrations when iron is absorbed from the diet or released from reticuloendothelial cells. We now show that DF given by constant subcutaneous infusion does suppress parasitemia in P. falciparum-infected Aotus monkeys.

  2. Gametocytogenesis : the puberty of Plasmodium falciparum

    PubMed Central

    Talman, Arthur M; Domarle, Olivier; McKenzie, F Ellis; Ariey, Frédéric; Robert, Vincent

    2004-01-01

    The protozoan Plasmodium falciparum has a complex life cycle in which asexual multiplication in the vertebrate host alternates with an obligate sexual reproduction in the anopheline mosquito. Apart from the apparent recombination advantages conferred by sex, P. falciparum has evolved a remarkable biology and adaptive phenotypes to insure its transmission despite the dangers of sex. This review mainly focuses on the current knowledge on commitment to sexual development, gametocytogenesis and the evolutionary significance of various aspects of gametocyte biology. It goes further than pure biology to look at the strategies used to improve successful transmission. Although gametocytes are inevitable stages for transmission and provide a potential target to fight malaria, they have received less attention than the pathogenic asexual stages. There is a need for research on gametocytes, which are a fascinating stage, responsible to a large extent for the success of P. falciparum. PMID:15253774

  3. Plasmodium malariae blood-stage dynamics.

    PubMed

    McKenzie, F E; Jeffery, G M; Collins, W E

    2001-06-01

    We examine the dynamics of parasitemia, fever, and gametocytemia reflected in the preintervention charts of 180 malaria-naive U.S. neurosyphilis patients infected with the USPHS strain of Plasmodium malariae, for malariatherapy, focusing on the 84 charts for which more than 35 days of patency preceded intervention and daily records encompassed 92% or more of the duration of each infection. Inoculum size did not influence any outcome variable. Fevers (days with temperatures > or =101 F) followed patterns that fit recognized brood structures more often than did our approximations of merogony cycles (via local peaks in parasitemia), but neither closely fit textbook quartan patterns. There were no discernable patterns in gametocytemia. Successful transmission to mosquitoes increased following subcurative drug treatment but did not depend on detectable gametocytemia.

  4. Inhibition of Plasmodium Liver Infection by Ivermectin.

    PubMed

    Mendes, António M; Albuquerque, Inês S; Machado, Marta; Pissarra, Joana; Meireles, Patrícia; Prudêncio, Miguel

    2017-02-01

    Avermectins are powerful endectocides with an established potential to reduce the incidence of vector-borne diseases. Here, we show that several avermectins inhibit the hepatic stage of Plasmodium infection in vitro Notably, ivermectin potently inhibits liver infection in vivo by impairing parasite development inside hepatocytes. This impairment has a clear impact on the ensuing blood stage parasitemia, reducing disease severity and enhancing host survival. Ivermectin has been proposed as a tool to control malaria transmission because of its effects on the mosquito vector. Our study extends the effect of ivermectin to the early stages of mammalian host infection and supports the inclusion of this multipurpose drug in malaria control strategies. Copyright © 2017 Mendes et al.

  5. Plasmodium falciparum drug resistance in Angola.

    PubMed

    Fançony, Cláudia; Brito, Miguel; Gil, Jose Pedro

    2016-02-09

    Facing chloroquine drug resistance, Angola promptly adopted artemisinin-based combination therapy as the first-line to treat malaria. Currently, the country aims to consolidate malaria control, while preparing for the elimination of the disease, along with others African countries in the region. However, the remarkable capacity of Plasmodium to develop drug resistance represents an alarming threat for those achievements. Herein, the available, but relatively scarce and dispersed, information on malaria drug resistance in Angola, is reviewed and discussed. The review aims to inform but also to encourage future research studies that monitor and update the information on anti-malarial drug efficacy and prevalence of molecular markers of drug resistance, key fields in the context and objectives of elimination.

  6. Wanted Plasmodium falciparum, dead or alive

    PubMed Central

    Sow, Fatimata; Nyonda, Mary; Bienvenu, Anne-Lise; Picot, Stephane

    2015-01-01

    Mechanisms of cell death in unicellular parasites have been subjects of debate for the last decade, with studies demonstrating evidence of apoptosis or non-apoptosis like mechanisms, including necrosis, and autophagy. Recent clarifications on the definition of regulated or accidental cell death by The Nomenclature Committee on Cell Death provides an opportunity to reanalyze some data, re-evaluate conclusions in the light of parasite diversity, and to propose alternative arguments in the context of malaria drug resistance, considering lack of really new drugs in the pipeline. Deciphering the mechanisms of death may help in detection of new drug targets and the design of innovative drugs. However, classifications have been evolving rapidly since initial description of “programmed cell death”, leading to some uncertainty as to whether Plasmodium cell death is accidental or regulated. PMID:28357297

  7. Development of vaccines for Plasmodium vivax malaria.

    PubMed

    Mueller, Ivo; Shakri, Ahmad Rushdi; Chitnis, Chetan E

    2015-12-22

    Plasmodium vivax continues to cause significant morbidity outside Africa with more than 50% of malaria cases in many parts of South and South-east Asia, Pacific islands, Central and South America being attributed to P. vivax infections. The unique biology of P. vivax, including its ability to form latent hypnozoites that emerge months to years later to cause blood stage infections, early appearance of gametocytes before clinical symptoms are apparent and a shorter development cycle in the vector makes elimination of P. vivax using standard control tools difficult. The availability of an effective vaccine that provides protection and prevents transmission would be a valuable tool in efforts to eliminate P. vivax. Here, we review the latest developments related to P. vivax malaria vaccines and discuss the challenges as well as directions toward the goal of developing highly efficacious vaccines against P. vivax malaria.

  8. Inhibition of Plasmodium Liver Infection by Ivermectin

    PubMed Central

    Mendes, António M.; Albuquerque, Inês S.; Machado, Marta; Pissarra, Joana; Meireles, Patrícia

    2016-01-01

    ABSTRACT Avermectins are powerful endectocides with an established potential to reduce the incidence of vector-borne diseases. Here, we show that several avermectins inhibit the hepatic stage of Plasmodium infection in vitro. Notably, ivermectin potently inhibits liver infection in vivo by impairing parasite development inside hepatocytes. This impairment has a clear impact on the ensuing blood stage parasitemia, reducing disease severity and enhancing host survival. Ivermectin has been proposed as a tool to control malaria transmission because of its effects on the mosquito vector. Our study extends the effect of ivermectin to the early stages of mammalian host infection and supports the inclusion of this multipurpose drug in malaria control strategies. PMID:27895022

  9. Epidemiology of Plasmodium vivax Malaria in Peru.

    PubMed

    Rosas-Aguirre, Angel; Gamboa, Dionicia; Manrique, Paulo; Conn, Jan E; Moreno, Marta; Lescano, Andres G; Sanchez, Juan F; Rodriguez, Hugo; Silva, Hermann; Llanos-Cuentas, Alejandro; Vinetz, Joseph M

    2016-12-28

    Malaria in Peru, dominated by Plasmodium vivax, remains a public health problem. The 1990s saw newly epidemic malaria emerge, primarily in the Loreto Department in the Amazon region, including areas near to Iquitos, the capital city, but sporadic malaria transmission also occurred in the 1990s-2000s in both north-coastal Peru and the gold mining regions of southeastern Peru. Although a Global Fund-supported intervention (PAMAFRO, 2005-2010) was temporally associated with a decrease of malaria transmission, from 2012 to the present, both P. vivax and Plasmodium falciparum malaria cases have rapidly increased. The Peruvian Ministry of Health continues to provide artemesinin-based combination therapy for microscopy-confirmed cases of P. falciparum and chloroquine-primaquine for P. vivax Malaria transmission continues in remote areas nonetheless, where the mobility of humans and parasites facilitates continued reintroduction outside of ongoing surveillance activities, which is critical to address for future malaria control and elimination efforts. Ongoing P. vivax research gaps in Peru include the following: identification of asymptomatic parasitemics, quantification of the contribution of patent and subpatent parasitemics to mosquito transmission, diagnosis of nonparasitemic hypnozoite carriers, and implementation of surveillance for potential emergence of chloroquine- and 8-aminoquinoline-resistant P. vivax Clinical trials of tafenoquine in Peru have been promising, and glucose-6-phosphate dehydrogenase deficiency in the region has not been observed to be a limitation to its use. Larger-scale challenges for P. vivax (and malaria in general) in Peru include logistical difficulties in accessing remote riverine populations, consequences of government policy and poverty trends, and obtaining international funding for malaria control and elimination. © The American Society of Tropical Medicine and Hygiene.

  10. Epidemiology of Plasmodium vivax Malaria in Peru

    PubMed Central

    Rosas-Aguirre, Angel; Gamboa, Dionicia; Manrique, Paulo; Conn, Jan E.; Moreno, Marta; Lescano, Andres G.; Sanchez, Juan F.; Rodriguez, Hugo; Silva, Hermann; Llanos-Cuentas, Alejandro; Vinetz, Joseph M.

    2016-01-01

    Malaria in Peru, dominated by Plasmodium vivax, remains a public health problem. The 1990s saw newly epidemic malaria emerge, primarily in the Loreto Department in the Amazon region, including areas near to Iquitos, the capital city, but sporadic malaria transmission also occurred in the 1990s–2000s in both north-coastal Peru and the gold mining regions of southeastern Peru. Although a Global Fund-supported intervention (PAMAFRO, 2005–2010) was temporally associated with a decrease of malaria transmission, from 2012 to the present, both P. vivax and Plasmodium falciparum malaria cases have rapidly increased. The Peruvian Ministry of Health continues to provide artemesinin-based combination therapy for microscopy-confirmed cases of P. falciparum and chloroquine–primaquine for P. vivax. Malaria transmission continues in remote areas nonetheless, where the mobility of humans and parasites facilitates continued reintroduction outside of ongoing surveillance activities, which is critical to address for future malaria control and elimination efforts. Ongoing P. vivax research gaps in Peru include the following: identification of asymptomatic parasitemics, quantification of the contribution of patent and subpatent parasitemics to mosquito transmission, diagnosis of nonparasitemic hypnozoite carriers, and implementation of surveillance for potential emergence of chloroquine- and 8-aminoquinoline-resistant P. vivax. Clinical trials of tafenoquine in Peru have been promising, and glucose-6-phosphate dehydrogenase deficiency in the region has not been observed to be a limitation to its use. Larger-scale challenges for P. vivax (and malaria in general) in Peru include logistical difficulties in accessing remote riverine populations, consequences of government policy and poverty trends, and obtaining international funding for malaria control and elimination. PMID:27799639

  11. Discordance in drug resistance-associated mutation patterns in marker genes of Plasmodium falciparum and Plasmodium knowlesi during coinfections.

    PubMed

    Tyagi, Rupesh K; Das, Manoj K; Singh, Shiv S; Sharma, Yagya D

    2013-05-01

    Human Plasmodium knowlesi infections have been reported from several South-East Asian countries, excluding India, but its drug susceptibility profile in mixed-infection cases remains unknown. The chloroquine resistance transporter (CRT) and dihydrofolate reductase (DHFR) genes of P. knowlesi and other Plasmodium species were sequenced from clinical isolates obtained from malaria patients living in the Andaman and Nicobar Islands, India. The merozoite surface protein-1 and 18S rRNA genes of P. knowlesi were also sequenced from these isolates. Among 445 samples analysed, only 53 of them had P. knowlesi-specific gene sequences. While 3 of the 53 cases (5.66%) had P. knowlesi monoinfection, the rest were coinfected with Plasmodium falciparum (86.79%, n = 46) or Plasmodium vivax (7.55%, n = 4), but none with Plasmodium malariae or Plasmodium ovale. There was discordance in the drug resistance-associated mutations among the coinfecting Plasmodium species. This is because the P. knowlesi isolates contained wild-type sequences, while P. falciparum isolates had mutations in the CRT and DHFR marker genes associated with a higher level of chloroquine and antifolate drug resistance, respectively. The mutation pattern indicates that the same patient, having a mixed infection, may be harbouring the drug-susceptible P. knowlesi parasite and a highly drug-resistant P. falciparum parasite. A larger human population in South-East Asia may be at risk of P. knowlesi infection than reported so far. The different drug susceptibility genotypes of P. knowlesi from its coinfecting Plasmodium species in mixed infections adds a new dimension to the malaria control programme, requiring formulation of an appropriate drug policy.

  12. FRET peptides reveal differential proteolytic activation in intraerythrocytic stages of the malaria parasites Plasmodium berghei and Plasmodium yoelii.

    PubMed

    Cruz, Laura Nogueira da; Alves, Eduardo; Leal, Mônica Teixeira; Juliano, Maria A; Rosenthal, Philip J; Juliano, Luiz; Garcia, Celia R S

    2011-03-01

    Malaria is still a major health problem in developing countries. It is caused by the protist parasite Plasmodium, in which proteases are activated during the cell cycle. Ca(2+) is a ubiquitous signalling ion that appears to regulate protease activity through changes in its intracellular concentration. Proteases are crucial to Plasmodium development, but the role of Ca(2+) in their activity is not fully understood. Here we investigated the role of Ca(2+) in protease modulation among rodent Plasmodium spp. Using fluorescence resonance energy transfer (FRET) peptides, we verified protease activity elicited by Ca(2+) from the endoplasmatic reticulum (ER) after stimulation with thapsigargin (a sarco/endoplasmatic reticulum Ca(2+)-ATPase (SERCA) inhibitor) and from acidic compartments by stimulation with nigericin (a K(+)/H(+) exchanger) or monensin (a Na(+)/H(+) exchanger). Intracellular (BAPTA/AM) and extracellular (EGTA) Ca(2+) chelators were used to investigate the role played by Ca(2+) in protease activation. In Plasmodium berghei both EGTA and BAPTA blocked protease activation, whilst in Plasmodium yoelii these compounds caused protease activation. The effects of protease inhibitors on thapsigargin-induced proteolysis also differed between the species. Pepstatin A and phenylmethylsulphonyl fluoride (PMSF) increased thapsigargin-induced proteolysis in P. berghei but decreased it in P. yoelii. Conversely, E64 reduced proteolysis in P. berghei but stimulated it in P. yoelii. The data point out key differences in proteolytic responses to Ca(2+) between species of Plasmodium. Copyright © 2011 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

  13. Primate malarias: Diversity, distribution and insights for zoonotic Plasmodium.

    PubMed

    Faust, Christina; Dobson, Andrew P

    2015-12-01

    Protozoans within the genus Plasmodium are well-known as the causative agents of malaria in humans. Numerous Plasmodium species parasites also infect a wide range of non-human primate hosts in tropical and sub-tropical regions worldwide. Studying this diversity can provide critical insight into our understanding of human malarias, as several human malaria species are a result of host switches from non-human primates. Current spillover of a monkey malaria, Plasmodium knowlesi, in Southeast Asia highlights the permeability of species barriers in Plasmodium. Also recently, surveys of apes in Africa uncovered a previously undescribed diversity of Plasmodium in chimpanzees and gorillas. Therefore, we carried out a meta-analysis to quantify the global distribution, host range, and diversity of known non-human primate malaria species. We used published records of Plasmodium parasites found in non-human primates to estimate the total diversity of non-human primate malarias globally. We estimate that at least three undescribed primate malaria species exist in sampled primates, and many more likely exist in unstudied species. The diversity of malaria parasites is especially uncertain in regions of low sampling such as Madagascar, and taxonomic groups such as African Old World Monkeys and gibbons. Presence-absence data of malaria across primates enables us to highlight the close association of forested regions and non-human primate malarias. This distribution potentially reflects a long coevolution of primates, forest-adapted mosquitoes, and malaria parasites. The diversity and distribution of primate malaria are an essential prerequisite to understanding the mechanisms and circumstances that allow Plasmodium to jump species barriers, both in the evolution of malaria parasites and current cases of spillover into humans.

  14. Re-evaluation of microscopy confirmed Plasmodium falciparum and Plasmodium vivax malaria by nested PCR detection in southern Ethiopia.

    PubMed

    Mekonnen, Seleshi Kebede; Aseffa, Abraham; Medhin, Girmay; Berhe, Nega; Velavan, Thirumalaisamy P

    2014-02-06

    With 75% of the Ethiopian population at risk of malaria, accurate diagnosis is crucial for malaria treatment in endemic areas where Plasmodium falciparum and Plasmodium vivax co-exist. The present study evaluated the performance of regular microscopy in accurate identification of Plasmodium spp. in febrile patients visiting health facilities in southern Ethiopia. A cross-sectional study design was employed to recruit study subjects who were microscopically positive for malaria parasites and attending health facilities in southern Ethiopia between August and December 2011. Of the 1,416 febrile patients attending primary health facilities, 314 febrile patients, whose slides were positive for P. falciparum, P. vivax or mixed infections using microscopy, were re-evaluated for their infection status by PCR. Finger-prick blood samples were used for parasite genomic DNA extraction. Phylogenetic analyses were performed to reconstruct the distribution of different Plasmodium spp. across the three geographical areas. Of the 314 patients with a positive thick blood smear, seven patients (2%) were negative for any of the Plasmodium spp. by nested PCR. Among 180 microscopically diagnosed P. falciparum cases, 111 (61.7%) were confirmed by PCR, 44 (24.4%) were confirmed as P. vivax, 18 (10%) had mixed infections with P. falciparum and P. vivax and two (1.1%) were mixed infections with P. falciparum and P. malariae and five (2.8%) were negative for any of the Plasmodium spp. Of 131 microscopically diagnosed P. vivax cases, 110 (84%) were confirmed as P. vivax, 14 (10.7%) were confirmed as P. falciparum, two (1.5%) were P. malariae, three (2.3%) with mixed infections with P. falciparum and P. vivax and two (1.5%) were negative for any of the Plasmodium spp. Plasmodium falciparum and P. vivax mixed infections were observed. Plasmodium malariae was detected as mono and mixed infections in four individuals. False positivity, under-reporting of mixed infections and a significant number

  15. Plasmodium vivax cerebral malaria complicated with venous sinus thrombosis in Colombia.

    PubMed

    Pinzón, Miguel A; Pineda, Juan C; Rosso, Fernando; Shinchi, Masaru; Bonilla-Abadía, Fabio

    2013-05-13

    Complicated malaria is usually due to Plasmodium falciparum. Nevertheless, Plasmodium vivax is infrequently related with life-threatening complications. Few cases have been reported of severe Plasmodium vivax infection, and most of them from Southeast Asia and India. We report the first case of cerebral malaria due to Plasmodium vivax in Latin America, complicated with sagittal sinus thrombosis and confirmed by a molecular method. Copyright © 2013 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

  16. Rediscovery and redescription of Plasmodium pifanoi and description of two additional Plasmodium parasites of Venezuelan lizards.

    PubMed

    Telford, Sam R; Telford, Sam R

    2003-04-01

    Plasmodium pifanoi Scorza and Dagert B., known only from the type host, Ameiva ameiva, is redescribed from Kentropyx calcarata collected in Territorio Amazonas, Venezuela. Schizonts, 6.2 x 4.5 (4-8 x 3-6), produce on average 11.9 (7-16) merozoites. Gametocytes average 12.4 x 6.0 (8-16 x 4-10), with length x width (LW) 72.9 (52-112) and L/W 2.18 (1.1-3.3), and always contain 1-5 prominent vacuoles. Macrogametocytes in active infection are longer than microgametocytes, with greater LW, but gametocytes in chronic infection are not sexually dimorphic in dimension and are slightly smaller. Two additional malarial parasites are described from K. calcarata. Plasmodium lepidoptiformis has small schizonts, 4.6 x 3.2 (3-6 x 2.5-3), that produce 5.1 (4-8) merozoites and commonly resemble a butterfly in appearance. Gametocytes are elongate, 9.0 x 4.3 (7-10 x 3-6), with LW 38.3 (24-51) and L/W 2.2 (1.3-3.3), and sexually dimorphic, with macrogametocytes longer than microgametocytes, with greater LW. Plasmodium minasense calcaratae is characterized by very small, usually fan-shaped, schizonts. 3.4 x 2.6 (2.5-4.5 x 2.0-3.0), that produce 3.9 (3-4) merozoites. Gametocytes are spherical or ovoid, 6.7 x 5.0 (4.5-9.0 x 3.0-7.0), with LW 33.7 (15-54) and L/W 1.4 (1.0-2.3), with no sexual dimorphism in dimensions.

  17. Maternal-foetal transfer of Plasmodium falciparum and Plasmodium vivax antibodies in a low transmission setting.

    PubMed

    Charnaud, Sarah C; McGready, Rose; Herten-Crabb, Asha; Powell, Rosanna; Guy, Andrew; Langer, Christine; Richards, Jack S; Gilson, Paul R; Chotivanich, Kesinee; Tsuboi, Takafumi; Narum, David L; Pimanpanarak, Mupawjay; Simpson, Julie A; Beeson, James G; Nosten, François; Fowkes, Freya J I

    2016-02-10

    During pregnancy immunoglobulin G (IgG) antibodies are transferred from mother to neonate across the placenta. Studies in high transmission areas have shown transfer of P. falciparum-specific IgG, but the extent and factors influencing maternal-foetal transfer in low transmission areas co-endemic for both P. falciparum and P. vivax are unknown. Pregnant women were screened weekly for Plasmodium infection. Mother-neonate paired serum samples at delivery were tested for IgG to antigens from P. falciparum, P. vivax and other infectious diseases. Antibodies to malarial and non-malarial antigens were highly correlated between maternal and neonatal samples (median [range] spearman ρ = 0.78 [0.57-0.93]), although Plasmodium spp. antibodies tended to be lower in neonates than mothers. Estimated gestational age at last P. falciparum infection, but not P. vivax infection, was positively associated with antibody levels in the neonate (P. falciparum merozoite, spearman ρ median [range] 0.42 [0.33-0.66], PfVAR2CSA 0.69; P. vivax ρ = 0.19 [0.09-0.3]). Maternal-foetal transfer of anti-malarial IgG to Plasmodium spp. antigens occurs in low transmission settings. P. vivax IgG acquisition is not associated with recent exposure unlike P. falciparum IgG, suggesting a difference in acquisition of antibodies. IgG transfer is greatest in the final weeks of pregnancy which has implications for the timing of future malaria vaccination strategies in pregnant women.

  18. Maternal-foetal transfer of Plasmodium falciparum and Plasmodium vivax antibodies in a low transmission setting

    PubMed Central

    Charnaud, Sarah C.; McGready, Rose; Herten-Crabb, Asha; Powell, Rosanna; Guy, Andrew; Langer, Christine; Richards, Jack S.; Gilson, Paul R.; Chotivanich, Kesinee; Tsuboi, Takafumi; Narum, David L.; Pimanpanarak, Mupawjay; Simpson, Julie A.; Beeson, James G.; Nosten, François; Fowkes, Freya J. I.

    2016-01-01

    During pregnancy immunolglobulin G (IgG) antibodies are transferred from mother to neonate across the placenta. Studies in high transmission areas have shown transfer of P. falciparum-specific IgG, but the extent and factors influencing maternal-foetal transfer in low transmission areas co-endemic for both P. falciparum and P. vivax are unknown. Pregnant women were screened weekly for Plasmodium infection. Mother-neonate paired serum samples at delivery were tested for IgG to antigens from P. falciparum, P. vivax and other infectious diseases. Antibodies to malarial and non-malarial antigens were highly correlated between maternal and neonatal samples (median [range] spearman ρ = 0.78 [0.57–0.93]), although Plasmodium spp. antibodies tended to be lower in neonates than mothers. Estimated gestational age at last P. falciparum infection, but not P. vivax infection, was positively associated with antibody levels in the neonate (P. falciparum merozoite, spearman ρ median [range] 0.42 [0.33–0.66], PfVAR2CSA 0.69; P. vivax ρ = 0.19 [0.09–0.3]). Maternal-foetal transfer of anti-malarial IgG to Plasmodium spp. antigens occurs in low transmission settings. P. vivax IgG acquisition is not associated with recent exposure unlike P. falciparum IgG, suggesting a difference in acquisition of antibodies. IgG transfer is greatest in the final weeks of pregnancy which has implications for the timing of future malaria vaccination strategies in pregnant women. PMID:26861682

  19. High prevalence and genetic diversity of Plasmodium malariae and no evidence of Plasmodium knowlesi in Bangladesh.

    PubMed

    Fuehrer, Hans-Peter; Swoboda, Paul; Harl, Josef; Starzengruber, Peter; Habler, Verena Elisabeth; Bloeschl, Ingrid; Haque, Rashidul; Matt, Julia; Khan, Wasif Ali; Noedl, Harald

    2014-04-01

    Although the prevalence of malaria remains high in parts of Bangladesh, there continues to be a substantial shortage of information regarding the less common malaria parasites such as Plasmodium malariae or Plasmodium knowlesi. Recent studies indicate that P. malariae may be extremely rare, and so far, there are no data on the presence (or absence) of P. knowlesi in southeastern Bangladesh. Genus- and species-specific nested polymerase chain reaction (PCR) analysis of the small subunit ribosomal RNA gene was performed to assess the presence and prevalence of P. malariae and P. knowlesi in 2,246 samples originating from asymptomatic and febrile participants of a cross-sectional and a febrile illnesses study in the Chittagong Hill Tracts in southeastern Bangladesh. P. malariae was detected in 60 samples (2.7%) corresponding to 8% of the 746 samples giving positive PCR results for Plasmodium sp., mainly because of the high prevalence (9.5%) among asymptomatic study participants testing positive for malaria. Symptomatic cases were more common (4.3% of all symptomatic malaria cases) during the dry season. Parasitemias were low (1,120-2,560/μl in symptomatic and 120-520/μl in asymptomatic carriers). Symptomatic patients presented mild to moderate symptoms like fever, chills, headache, dizziness, fatigue and myalgia.Although both the intermediate as well as the definite host are known to be endemic in southeastern Bangladesh, no evidence for the presence of P. knowlesi was found. We conclude that the role of P. malariae is highly underestimated in rural Bangladesh with major implications for malaria control and elimination strategies.

  20. Avian Malaria ( Plasmodium spp.) in Captive Magellanic Penguins ( Spheniscus magellanicus ) from Northern Argentina, 2010.

    PubMed

    Vanstreels, Ralph Eric Thijl; Capellino, Félix; Silveira, Patricia; Braga, Érika M; Rodríguez-Heredia, Sergio Andres; Loureiro, Julio; Catão-Dias, José Luiz

    2016-07-01

    We report two cases of lethal avian malaria in Magellanic Penguins (Spheniscus magellanicus) captive at San Clemente del Tuyú, Argentina, approximately 560 km north of Argentinean breeding colonies of Magellanic Penguins. Blood smears revealed both penguins were concurrently infected by Plasmodium (Haemamoeba) tejerai, Plasmodium (Huffia) sp., and Plasmodium (Novyella) sp.

  1. Susceptibility of human Plasmodium knowlesi infections to anti-malarials

    PubMed Central

    2013-01-01

    Background Evidence suggests that Plasmodium knowlesi malaria in Sarawak, Malaysian Borneo remains zoonotic, meaning anti-malarial drug resistance is unlikely to have developed in the absence of drug selection pressure. Therefore, adequate response to available anti-malarial treatments is assumed. Methods Here the ex vivo sensitivity of human P. knowlesi isolates in Malaysian Borneo were studied, using a WHO schizont maturation assay modified to accommodate the quotidian life cycle of this parasite. The in vitro sensitivities of P. knowlesi H strain adapted from a primate infection to in vitro culture (by measuring the production of Plasmodium lactate dehydrogenase) were also examined together with some assays using Plasmodium falciparum and Plasmodium vivax. Results Plasmodium knowlesi is uniformly highly sensitive to artemisinins, variably and moderately sensitive to chloroquine, and less sensitive to mefloquine. Conclusions Taken together with reports of clinical failures when P. knowlesi is treated with mefloquine, the data suggest that caution is required if using mefloquine in prevention or treatment of P. knowlesi infections, until further studies are undertaken. PMID:24245918

  2. Wolbachia increases susceptibility to Plasmodium infection in a natural system

    PubMed Central

    Zélé, F.; Nicot, A.; Berthomieu, A.; Weill, M.; Duron, O.; Rivero, A.

    2014-01-01

    Current views about the impact of Wolbachia on Plasmodium infections are almost entirely based on data regarding artificially transfected mosquitoes. This work has shown that Wolbachia reduces the intensity of Plasmodium infections in mosquitoes, raising the exciting possibility of using Wolbachia to control or limit the spread of malaria. Whether natural Wolbachia infections have the same parasite-inhibiting properties is not yet clear. Wolbachia–mosquito combinations with a long evolutionary history are, however, key for understanding what may happen with Wolbachia-transfected mosquitoes after several generations of coevolution. We investigate this issue using an entirely natural mosquito–Wolbachia–Plasmodium combination. In contrast to most previous studies, which have been centred on the quantification of the midgut stages of Plasmodium, we obtain a measurement of parasitaemia that relates directly to transmission by following infections to the salivary gland stages. We show that Wolbachia increases the susceptibility of Culex pipiens mosquitoes to Plasmodium relictum, significantly increasing the prevalence of salivary gland stage infections. This effect is independent of the density of Wolbachia in the mosquito. These results suggest that naturally Wolbachia-infected mosquitoes may, in fact, be better vectors of malaria than Wolbachia-free ones. PMID:24500167

  3. Chimpanzee malaria parasites related to Plasmodium ovale in Africa.

    PubMed

    Duval, Linda; Nerrienet, Eric; Rousset, Dominique; Sadeuh Mba, Serge Alain; Houze, Sandrine; Fourment, Mathieu; Le Bras, Jacques; Robert, Vincent; Ariey, Frederic

    2009-01-01

    Since the 1970's, the diversity of Plasmodium parasites in African great apes has been neglected. Surprisingly, P. reichenowi, a chimpanzee parasite, is the only such parasite to have been molecularly characterized. This parasite is closely phylogenetically related to P. falciparum, the principal cause of the greatest malaria burden in humans. Studies of malaria parasites from anthropoid primates may provide relevant phylogenetic information, improving our understanding of the origin and evolutionary history of human malaria species. In this study, we screened 130 DNA samples from chimpanzees (Pan troglodytes) and gorillas (Gorilla gorilla) from Cameroon for Plasmodium infection, using cytochrome b molecular tools. Two chimpanzees from the subspecies Pan t. troglodytes presented single infections with Plasmodium strains molecularly related to the human malaria parasite P. ovale. These chimpanzee parasites and 13 human strains of P. ovale originated from a various sites in Africa and Asia were characterized using cytochrome b and cytochrome c oxidase 1 mitochondrial partial genes and nuclear ldh partial gene. Consistent with previous findings, two genetically distinct types of P. ovale, classical and variant, were observed in the human population from a variety of geographical locations. One chimpanzee Plasmodium strain was genetically identical, on all three markers tested, to variant P. ovale type. The other chimpanzee Plasmodium strain was different from P. ovale strains isolated from humans. This study provides the first evidence of possibility of natural cross-species exchange of P. ovale between humans and chimpanzees of the subspecies Pan t. troglodytes.

  4. Chimpanzee Malaria Parasites Related to Plasmodium ovale in Africa

    PubMed Central

    Duval, Linda; Nerrienet, Eric; Rousset, Dominique; Sadeuh Mba, Serge Alain; Houze, Sandrine; Fourment, Mathieu; Le Bras, Jacques; Robert, Vincent; Ariey, Frederic

    2009-01-01

    Since the 1970's, the diversity of Plasmodium parasites in African great apes has been neglected. Surprisingly, P. reichenowi, a chimpanzee parasite, is the only such parasite to have been molecularly characterized. This parasite is closely phylogenetically related to P. falciparum, the principal cause of the greatest malaria burden in humans. Studies of malaria parasites from anthropoid primates may provide relevant phylogenetic information, improving our understanding of the origin and evolutionary history of human malaria species. In this study, we screened 130 DNA samples from chimpanzees (Pan troglodytes) and gorillas (Gorilla gorilla) from Cameroon for Plasmodium infection, using cytochrome b molecular tools. Two chimpanzees from the subspecies Pan t. troglodytes presented single infections with Plasmodium strains molecularly related to the human malaria parasite P. ovale. These chimpanzee parasites and 13 human strains of P. ovale originated from a various sites in Africa and Asia were characterized using cytochrome b and cytochrome c oxidase 1 mitochondrial partial genes and nuclear ldh partial gene. Consistent with previous findings, two genetically distinct types of P. ovale, classical and variant, were observed in the human population from a variety of geographical locations. One chimpanzee Plasmodium strain was genetically identical, on all three markers tested, to variant P. ovale type. The other chimpanzee Plasmodium strain was different from P. ovale strains isolated from humans. This study provides the first evidence of possibility of natural cross-species exchange of P. ovale between humans and chimpanzees of the subspecies Pan t. troglodytes. PMID:19436742

  5. Wolbachia increases susceptibility to Plasmodium infection in a natural system.

    PubMed

    Zélé, F; Nicot, A; Berthomieu, A; Weill, M; Duron, O; Rivero, A

    2014-03-22

    Current views about the impact of Wolbachia on Plasmodium infections are almost entirely based on data regarding artificially transfected mosquitoes. This work has shown that Wolbachia reduces the intensity of Plasmodium infections in mosquitoes, raising the exciting possibility of using Wolbachia to control or limit the spread of malaria. Whether natural Wolbachia infections have the same parasite-inhibiting properties is not yet clear. Wolbachia-mosquito combinations with a long evolutionary history are, however, key for understanding what may happen with Wolbachia-transfected mosquitoes after several generations of coevolution. We investigate this issue using an entirely natural mosquito-Wolbachia-Plasmodium combination. In contrast to most previous studies, which have been centred on the quantification of the midgut stages of Plasmodium, we obtain a measurement of parasitaemia that relates directly to transmission by following infections to the salivary gland stages. We show that Wolbachia increases the susceptibility of Culex pipiens mosquitoes to Plasmodium relictum, significantly increasing the prevalence of salivary gland stage infections. This effect is independent of the density of Wolbachia in the mosquito. These results suggest that naturally Wolbachia-infected mosquitoes may, in fact, be better vectors of malaria than Wolbachia-free ones.

  6. Small molecule screen for candidate antimalarials targeting Plasmodium Kinesin-5.

    PubMed

    Liu, Liqiong; Richard, Jessica; Kim, Sunyoung; Wojcik, Edward J

    2014-06-06

    Plasmodium falciparum and vivax are responsible for the majority of malaria infections worldwide, resulting in over a million deaths annually. Malaria parasites now show measured resistance to all currently utilized drugs. Novel antimalarial drugs are urgently needed. The Plasmodium Kinesin-5 mechanoenzyme is a suitable "next generation" target. Discovered via small molecule screen experiments, the human Kinesin-5 has multiple allosteric sites that are "druggable." One site in particular, unique in its sequence divergence across all homologs in the superfamily and even within the same family, exhibits exquisite drug specificity. We propose that Plasmodium Kinesin-5 shares this allosteric site and likewise can be targeted to uncover inhibitors with high specificity. To test this idea, we performed a screen for inhibitors selective for Plasmodium Kinesin-5 ATPase activity in parallel with human Kinesin-5. Our screen of nearly 2000 compounds successfully identified compounds that selectively inhibit both P. vivax and falciparum Kinesin-5 motor domains but, as anticipated, do not impact human Kinesin-5 activity. Of note is a candidate drug that did not biochemically compete with the ATP substrate for the conserved active site or disrupt the microtubule-binding site. Together, our experiments identified MMV666693 as a selective allosteric inhibitor of Plasmodium Kinesin-5; this is the first identified protein target for the Medicines of Malaria Venture validated collection of parasite proliferation inhibitors. This work demonstrates that chemical screens against human kinesins are adaptable to homologs in disease organisms and, as such, extendable to strategies to combat infectious disease.

  7. Loop-Mediated Isothermal Amplification and LFD Combination for Detection of Plasmodium falciparum and Plasmodium vivax.

    PubMed

    Kongkasuriyachai, Darin; Yongkiettrakul, Suganya; Kiatpathomchai, Wansika; Arunrut, Narong

    2017-01-01

    Loop-mediated isothermal amplification (LAMP) has been used to detect several pathogens including malaria parasites from field and clinical samples. In this protocol, the malaria LAMP technology is developed to differentiate between Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) species by targeting the dihydrofolate reductase thymidylate synthase (dhfr-ts) gene, a known target for the antifolate class of drugs such as Pyrimethamine. LAMP primer sets are designed and validated for species specific amplification. Additionally, specific probes help improve detection and visualization of the products when combined with lateral flow dipstick-based (LFD) detection. The protocols are further simplified to eliminate tedious sample preparation steps, such that crude lysis prepared simply by diluting few microliter (μL) of blood sample with distilled water is sufficient. The LAMP-LFD malaria dhfr-ts protocols are sensitive and can detect as little as 1 picogram (pg) of PfDNA and 1 nanogram (ng) of PvDNA, or a few microliters of crude lysate from infected blood samples (Yongkiettrakul et al., Parasitol Int 63: 777-784, 2014). These simplified steps not only reduce cost but also increase the potential for large application in the fields and clinical settings.

  8. Clinico-pathological studies of Plasmodium falciparum and Plasmodium vivax - malaria in India and Saudi Arabia.

    PubMed

    Khan, Wajihullah; Zakai, Haytham A; Umm-E-Asma

    2014-06-01

    Malaria is one of the most devastating diseases of tropical countries with clinical manifestations such as anaemia, splenomegaly, thrombocytopenia, hepatomegaly and acute renal failures. In this study, cases of thrombocytopenia and haemoglobinemia were more prominent in subjects infected with Plasmodium falciparum (Welch, 1897) than those with Plasmodium vivax (Grassi et Feletti, 1890). However, anaemia, jaundice, convulsions and acute renal failure were significantly high (3-4 times) in subjects infected with P. falciparum than those infected with P. vivax. The incidence of splenomegaly and neurological sequelae were 2 and 6 times higher in P. falciparum infections compared to the infections of P. vivax. Both in P. vivax and P. falciparum malaria, the cases of splenomegaly, jaundice and neurological sequelae were almost double in children (<10 years) compared to older patients. The liver enzymes were generally in normal range in cases of low and mild infections. However, the AST, ALT, ALP activities and serum bilirubin, creatinine, and the urea content were increased in P. falciparum and P. vivax malaria patients having high parasitaemia, confirming liver dysfunction and renal failures in few cases of severe malaria both in India and Saudi Arabia.

  9. PLASMODIUM VIVAX BLOOD-STAGE DYNAMICS

    PubMed Central

    McKenzie, F. Ellis; Jeffery, Geoffrey M.; Collins, William E.

    2008-01-01

    We examine the dynamics of parasitemia and gametocytemia reflected in the preintervention charts of 221 malaria-naive U.S. neurosyphilis patients infected with the St. Elizabeth strain of Plasmodium vivax, for malariatherapy, focusing on the 109 charts for which 15 or more days of patency preceded intervention and daily records encompassed an average 98% of the duration of each infection. Our approximations of merogony cycles (via “local peaks” in parasitemia) seldom fit patterns that correspond to “textbook” tertian brood structures. Peak parasitemia was higher in trophozoite-induced infections than in sporozoite-induced ones. Relative densities of male and female gametocytes appeared to alternate, though without a discernably regular period. Successful transmission to mosquitoes did not depend on detectable gametocytemia or on absence of fever. When gametocytes were detected, transmission success depended on densities of only male gametocytes. Successful feeds occurred on average 4.7 days later in an infection than did failures. Parasitemia was lower in homologous reinfection, gametocytemia lower or absent. PMID:12099421

  10. Elimination of Plasmodium vivax Malaria in Azerbaijan

    PubMed Central

    Mammadov, Suleyman; Gasimov, Elkhan; Kurdova-Mintcheva, Rossitza; Wongsrichanalai, Chansuda

    2016-01-01

    Azerbaijan in the south caucasus region of far southeastern Europe has a long history of malaria endemicity but just successfully eliminated local transmission. After a period of relatively stable malaria situation (1960–1970), the country witnessed an epidemic followed by a series of outbreaks of various magnitudes in the following two decades, all caused by Plasmodium vivax. Compared with 1993, the number of malaria cases in the country jumped 29 times in 1994, 123 times in 1995, and 571 times in 1996 at the peak of the epidemic, when 13,135 cases were officially registered. Incidence rate increased dramatically from 0.2/100,000 population in 1991 to over 17/100,000 population in 1996. Scaled-up malaria control led to the containment of the epidemic and to a dramatic decrease of malaria burden nationwide. Azerbaijan has applied contemporary, complex control and surveillance strategies and approaches and is currently in the prevention of reintroduction phase. This article describes Azerbaijan's public health experience in conducting malaria control and elimination interventions over several decades until 2013 when the country reached an important milestone—no indigenous malaria cases were recorded. PMID:27708184

  11. The Motor Complex of Plasmodium falciparum

    PubMed Central

    Green, Judith L.; Rees-Channer, Roxanne R.; Howell, Stephen A.; Martin, Stephen R.; Knuepfer, Ellen; Taylor, Helen M.; Grainger, Munira; Holder, Anthony A.

    2008-01-01

    Calcium-dependent protein kinases (CDPKs) of Apicomplexan parasites are crucial for the survival of the parasite throughout its life cycle. CDPK1 is expressed in the asexual blood stages of the parasite, particularly late stage schizonts. We have identified two substrates of Plasmodium falciparum CDPK1: myosin A tail domain-interacting protein (MTIP) and glideosome-associated protein 45 (GAP45), both of which are components of the motor complex that generates the force required by the parasite to actively invade host cells. Indirect immunofluorescence shows that CDPK1 localizes to the periphery of P. falciparum merozoites and is therefore suitably located to act on MTIP and GAP45 at the inner membrane complex. A proportion of both GAP45 and MTIP is phosphorylated in schizonts, and we demonstrate that both proteins can be efficiently phosphorylated by CDPK1 in vitro. A primary phosphorylation of MTIP occurs at serine 47, whereas GAP45 is phosphorylated at two sites, one of which could also be detected in phosphopeptides purified from parasite lysates. Both CDPK1 activity and host cell invasion can be inhibited by the kinase inhibitor K252a, suggesting that CDPK1 is a suitable target for antimalarial drug development. PMID:18768477

  12. Maurer's clefts, the enigma of Plasmodium falciparum

    PubMed Central

    Mundwiler-Pachlatko, Esther; Beck, Hans-Peter

    2013-01-01

    Plasmodium falciparum, the causative agent of malaria, completely remodels the infected human erythrocyte to acquire nutrients and to evade the immune system. For this process, the parasite exports more than 10% of all its proteins into the host cell cytosol, including the major virulence factor PfEMP1 (P. falciparum erythrocyte surface protein 1). This unusual protein trafficking system involves long-known parasite-derived membranous structures in the host cell cytosol, called Maurer’s clefts. However, the genesis, role, and function of Maurer’s clefts remain elusive. Similarly unclear is how proteins are sorted and how they are transported to and from these structures. Recent years have seen a large increase of knowledge but, as yet, no functional model has been established. In this perspective we review the most important findings and conclude with potential possibilities to shed light into the enigma of Maurer’s clefts. Understanding the mechanism and function of these structures, as well as their involvement in protein export in P. falciparum, might lead to innovative control strategies and might give us a handle with which to help to eliminate this deadly parasite. PMID:24284172

  13. Exploring the folate pathway in Plasmodium falciparum.

    PubMed

    Hyde, John E

    2005-06-01

    As in centuries past, the main weapon against human malaria infections continues to be intervention with drugs, despite the widespread and increasing frequency of parasite populations that are resistant to one or more of the available compounds. This is a particular problem with the lethal species of parasite, Plasmodium falciparum, which claims some two million lives per year as well as causing enormous social and economic problems. Amongst the antimalarial drugs currently in clinical use, the antifolates have the best defined molecular targets, namely the enzymes dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS), which function in the folate metabolic pathway. The products of this pathway, reduced folate cofactors, are essential for DNA synthesis and the metabolism of certain amino acids. Moreover, their formation and interconversions involve a number of other enzymes that have not as yet been exploited as drug targets. Antifolates are of major importance as they currently represent the only inexpensive regime for combating chloroquine-resistant malaria, and are now first-line drugs in a number of African countries. Aspects of our understanding of this pathway and antifolate drug resistance are reviewed here, with a particular emphasis on approaches to analysing the details of, and balance between, folate biosynthesis by the parasite and salvage of pre-formed folate from exogenous sources.

  14. Cellular effector mechanisms against Plasmodium liver stages.

    PubMed

    Frevert, Ute; Nardin, Elizabeth

    2008-10-01

    Advances in our understanding of the molecular and cell biology of the malaria parasite have led to new vaccine development efforts resulting in a pipeline of over 40 candidates undergoing clinical phase I-III trials. Vaccine-induced CD4+ and CD8+ T cells specific for pre-erythrocytic stage antigens have been found to express cytolytic and multi-cytokine effector functions that support a key role for these T cells within the hepatic environment. However, little is known of the cellular interactions that occur during the effector phase in which the intracellular hepatic stage of the parasite is targeted and destroyed. This review focuses on cell biological aspects of the interaction between malaria-specific effector cells and the various antigen-presenting cells that are known to exist within the liver, including hepatocytes, dendritic cells, Kupffer cells, stellate cells and sinusoidal endothelia. Considering the unique immune properties of the liver, it is conceivable that these different hepatic antigen-presenting cells fulfil distinct but complementary roles during the effector phase against Plasmodium liver stages.

  15. Regulation of the Plasmodium Motor Complex

    PubMed Central

    Douse, Christopher H.; Green, Judith L.; Salgado, Paula S.; Simpson, Peter J.; Thomas, Jemima C.; Langsley, Gordon; Holder, Anthony A.; Tate, Edward W.; Cota, Ernesto

    2012-01-01

    The interaction between the C-terminal tail of myosin A (MyoA) and its light chain, myosin A tail domain interacting protein (MTIP), is an essential feature of the conserved molecular machinery required for gliding motility and cell invasion by apicomplexan parasites. Recent data indicate that MTIP Ser-107 and/or Ser-108 are targeted for intracellular phosphorylation. Using an optimized MyoA tail peptide to reconstitute the complex, we show that this region of MTIP is an interaction hotspot using x-ray crystallography and NMR, and S107E and S108E mutants were generated to mimic the effect of phosphorylation. NMR relaxation experiments and other biophysical measurements indicate that the S108E mutation serves to break the tight clamp around the MyoA tail, whereas S107E has a smaller but measurable impact. These data are consistent with physical interactions observed between recombinant MTIP and native MyoA from Plasmodium falciparum lysates. Taken together these data support the notion that the conserved interactions between MTIP and MyoA may be specifically modulated by this post-translational modification. PMID:22932904

  16. An integrated model of Plasmodium falciparum dynamics.

    PubMed

    McKenzie, F Ellis; Bossert, William H

    2005-02-07

    The within-host and between-host dynamics of malaria are linked in myriad ways, but most obviously by gametocytes, the parasite blood forms transmissible from human to mosquito. Gametocyte dynamics depend on those of non-transmissible blood forms, which stimulate immune responses, impeding transmission as well as within-host parasite densities. These dynamics can, in turn, influence antigenic diversity and recombination between genetically distinct parasites. Here, we embed a differential-equation model of parasite-immune system interactions within each of the individual humans represented in a discrete-event model of Plasmodium falciparum transmission, and examine the effects of human population turnover, parasite antigenic diversity, recombination, and gametocyte production on the dynamics of malaria. Our results indicate that the local persistence of P. falciparum increases with turnover in the human population and antigenic diversity in the parasite, particularly in combination, and that antigenic diversity arising from meiotic recombination in the parasite has complex differential effects on the persistence of founder and progeny genotypes. We also find that reductions in the duration of individual human infectivity to mosquitoes, even if universal, produce population-level effects only if near-absolute, and that, in competition, the persistence and prevalence of parasite genotypes with gametocyte production concordant with data exceed those of genotypes with higher gametocyte production. This new, integrated approach provides a framework for investigating relationships between pathogen dynamics within an individual host and pathogen dynamics within interacting host and vector populations.

  17. Activity of selected phytochemicals against Plasmodium falciparum.

    PubMed

    Astelbauer, Florian; Gruber, Maria; Brem, Brigitte; Greger, Harald; Obwaller, Andreas; Wernsdorfer, Gunther; Congpuong, Kanungnit; Wernsdorfer, Walther H; Walochnik, Julia

    2012-08-01

    According to the WHO, in 2008, there were 247 million reported cases of malaria and nearly one million deaths from the disease. Parasite resistance against first-line drugs, including artemisinin and mefloquine, is increasing. In this study the plant-derived compounds aglafolin, rocaglamid, kokusaginine, arborine, arborinine and tuberostemonine were investigated for their anti-plasmodial activity in vitro. Fresh Plasmodium falciparum isolates were taken from patients in the area of Mae Sot, north-western Thailand in 2008 and the inhibition of schizont maturation was determined for the respective compounds. With inhibitory concentrations effecting 50%, 90% and 99% inhibition (IC(50), IC(90) and IC(99)) of 60.95 nM, 854.41 nM and 7351.49 nM, respectively, rocaglamid was the most active of the substances, closely followed by aglafoline with 53.49 nM, 864.55 nM and 8354.20 nM. The activity was significantly below that of artemisinin, but moderately higher than that of quinine. Arborine, arborinine, tuberostemonine and kokusaginine showed only marginal activity against P. falciparum characterized by IC(50) and IC(99) values higher than 350 nM and 180 μM, respectively, and regressions with relatively shallow slopes S>14.38. Analogues of rocaglamid and aglafoline merit further exploration of their anti-plasmodial activity.

  18. Induction of gene amplification in Plasmodium falciparum

    SciTech Connect

    Rogers, P.L.

    1985-01-01

    Human erythrocytic in vitro cultures of Honduras I strain of the malaria parasite Plasmodium falciparum have been stressed stepwise with increasing concentrations of methotrexate (MTX), a folate antagonist. This selection has produced a strain that is 450 times more resistant to the drug than the original culture. Uptake of sublethal doses of radiolabeled MTX by infected red blood cells was 6-36 times greater in the resistant cultures than in the nonresistant controls. DNA isolated from all of the parasites was probed by hybridization with /sup 35/S-labeled DNA derived from a clone of the yeast thymidylate synthetase (TS) gene. This showed 50 to 100 times more increased hybridization of the TS probe to the DNA from the resistant parasites is direct evidence of gene amplification because DHFR and TS are actually one and the same bifunctional enzyme in P. falciparum. Hence, the evidence presented indicates that induced resistance of the malaria parasite to MTX in this case is due to overproduction of DHFR resulting from amplification of the DHFR-TS gene.

  19. Temperature alters Plasmodium blocking by Wolbachia

    NASA Astrophysics Data System (ADS)

    Murdock, Courtney C.; Blanford, Simon; Hughes, Grant L.; Rasgon, Jason L.; Thomas, Matthew B.

    2014-02-01

    Very recently, the Asian malaria vector (Anopheles stephensi) was stably transinfected with the wAlbB strain of Wolbachia, inducing refractoriness to the human malaria parasite Plasmodium falciparum. However, conditions in the field can differ substantially from those in the laboratory. We use the rodent malaria P. yoelii, and somatically transinfected An. stephensi as a model system to investigate whether the transmission blocking potential of wAlbB is likely to be robust across different thermal environments. wAlbB reduced malaria parasite prevalence and oocyst intensity at 28°C. At 24°C there was no effect on prevalence but a marked increase in oocyst intensity. At 20°C, wAlbB had no effect on prevalence or intensity. Additionally, we identified a novel effect of wAlbB that resulted in reduced sporozoite development across temperatures, counterbalancing the oocyst enhancement at 24°C. Our results demonstrate complex effects of temperature on the Wolbachia-malaria interaction, and suggest the impacts of transinfection might vary across diverse environments.

  20. Malaria-like symptoms associated with a natural Plasmodium reichenowi infection in a chimpanzee.

    PubMed

    Herbert, Anaïs; Boundenga, Larson; Meyer, Anne; Moukodoum, Diamella Nancy; Okouga, Alain Prince; Arnathau, Céline; Durand, Patrick; Magnus, Julie; Ngoubangoye, Barthélémy; Willaume, Eric; Ba, Cheikh Tidiane; Rougeron, Virginie; Renaud, François; Ollomo, Benjamin; Prugnolle, Franck

    2015-05-28

    Although Plasmodium infections have never been clearly associated with symptoms in non-human primates, the question of the pathogenicity of Plasmodium parasites in non-human primates still remains unanswered. A young chimpanzee, followed before and after release to a sanctuary, in a semi-free ranging enclosure located in an equatorial forest, showed fever and strong anaemia associated with a high Plasmodium reichenowi infection, shortly after release. The animal recovered from anaemia after several months despite recurrent infection with other Plasmodium species. This may be the first description of malaria-like symptoms in a chimpanzee infected with Plasmodium.

  1. Optimal strategy for controlling the spread of Plasmodium Knowlesi malaria: Treatment and culling

    NASA Astrophysics Data System (ADS)

    Abdullahi, Mohammed Baba; Hasan, Yahya Abu; Abdullah, Farah Aini

    2015-05-01

    Plasmodium Knowlesi malaria is a parasitic mosquito-borne disease caused by a eukaryotic protist of genus Plasmodium Knowlesi transmitted by mosquito, Anopheles leucosphyrus to human and macaques. We developed and analyzed a deterministic Mathematical model for the transmission of Plasmodium Knowlesi malaria in human and macaques. The optimal control theory is applied to investigate optimal strategies for controlling the spread of Plasmodium Knowlesi malaria using treatment and culling as control strategies. The conditions for optimal control of the Plasmodium Knowlesi malaria are derived using Pontryagin's Maximum Principle. Finally, numerical simulations suggested that the combination of the control strategies is the best way to control the disease in any community.

  2. Diagnosis of an imported Plasmodium ovale wallikeri infection in Malaysia.

    PubMed

    Liew, Jonathan Wee Kent; Mahmud, Rohela; Tan, Lian Huat; Lau, Yee Ling

    2016-01-06

    Plasmodium ovale is rare and not exactly known to be autochthonous in Malaysia. There are two distinct forms of the parasite, namely P. ovale curtisi (classic form) and P. ovale wallikeri (variant form). Here, the first sequence confirmed case of an imported P. ovale wallikeri infection in Malaysia is presented. Microscopy found Plasmodium parasites with morphology similar to P. ovale or Plasmodium vivax in the blood films. Further confirmation using polymerase chain reaction (PCR) targeting the small-subunit rRNA gene of the parasite was unsuccessful. Genus-specific PCR was then performed and the product was sequenced and analysed. Sequence analyses confirmed the aetiological agent as P. ovale wallikeri. New species-specific primers (rOVA1v and rOVA2v) were employed and P. ovale wallikeri was finally confirmed. The findings highlight the need to look out for imported malaria infections in Malaysia and the importance of a constantly updated and validated diagnostic technique.

  3. Acute Disseminated Encephalomyelitis in a Child Following Plasmodium vivax Malaria.

    PubMed

    Purkait, Radheshyam; Mukherji, Aritra; Sinhamahapatra, Tapankumar; Bhadra, Ramchandra

    2015-07-01

    Acute Disseminated Encephalomyelitis (ADEM) is a multifocal, monophasic, acute demyelinating disease of the brain and spinal cord, which is commonly preceded by viral infections and occasionally bacterial infections or immunizations. Its occurrence following malarial infection, especially Plasmodium vivax Malaria is very uncommon. We report an 11-year girl who presented with clinical features of encephalopathy and generalized convulsions, 10 days following complete recovery from the Plasmodium vivax Malaria. Diagnosis of ADEM as a complication of Plasmodium vivax Malaria was made based on acute onset of neurological events, characteristic findings on Magnetic Resonance Imaging (MRI) of brain and prompt response to corticosteroid therapy. Follow-up MRI, 6 months after discharge, showed complete resolution of change found on the initial MRI. To the best of our knowledge, only two such cases have been reported in the English literature till date.

  4. Inhibition of Plasmodium sporozoites infection by targeting the host cell

    PubMed Central

    Leitao, Ricardo; Rodriguez, Ana

    2010-01-01

    There is a great need of new drugs against malaria because of the increasing spread of parasite resistance against the most commonly used drugs in the field. We found that monensin, a common veterinary antibiotic, has a strong inhibitory effect in Plasmodium berghei and P. yoelii sporozoites hepatocyte infection in vitro. Infection of host cells by another apicomplexan parasite with a similar mechanism of host cell invasion, Toxoplasma tachyzoites, was also inhibited. Treatment of mice with monensin abrogates liver infection with P. berghei sporozoites in vivo. We also found that at low concentrations monensin inhibits the infection of Plasmodium sporozoites by rendering host cells resistant to infection, rather than having a direct effect on sporozoites. Monensin effect is targeted to the initial stages of parasite invasion of the host cell with little or no effect on development, suggesting that this antibiotic affects an essential host cell component that is required for Plasmodium sporozoite invasion. PMID:20493847

  5. Inhibition of Glutathione Biosynthesis Sensitizes Plasmodium berghei to Antifolates

    PubMed Central

    Koonyosying, Pongpisid; Uthaipibull, Chairat; Kamchonwongpaisan, Sumalee

    2016-01-01

    Glutathione plays a central role in maintaining cellular redox homeostasis, and modulations to this status may affect malaria parasite sensitivity to certain types of antimalarials. In this study, we demonstrate that inhibition of glutathione biosynthesis in the Plasmodium berghei ANKA strain through disruption of the γ-glutamylcysteine synthetase (γ-GCS) gene, which encodes the first and rate-limiting enzyme in the glutathione biosynthetic pathway, significantly sensitizes parasites in vivo to pyrimethamine and sulfadoxine, but not to chloroquine, artesunate, or primaquine, compared with control parasites containing the same pyrimethamine-resistant marker cassette. Treatment of mice infected with an antifolate-resistant P. berghei control line with a γ-GCS inhibitor, buthionine sulfoximine, could partially abrogate pyrimethamine and sulfadoxine resistance. The role of glutathione in modulating the malaria parasite's response to antifolates suggests that development of specific inhibitors against Plasmodium γ-GCS may offer a new approach to counter Plasmodium antifolate resistance. PMID:26953195

  6. Plasmodium knowlesi: from severe zoonosis to animal model.

    PubMed

    Cox-Singh, Janet; Culleton, Richard

    2015-06-01

    Plasmodium knowlesi malaria is a newly described zoonosis in Southeast Asia. Similarly to Plasmodium falciparum, P. knowlesi can reach high parasitaemia in the human host and both species cause severe and fatal illness. Interpretation of host-parasite interactions in studies of P. knowlesi malaria adds a counterpoint to studies on P. falciparum. However, there is no model system for testing the resulting hypotheses on malaria pathophysiology or for developing new interventions. Plasmodium knowlesi is amenable to genetic manipulation in vitro and several nonhuman primate species are susceptible to experimental infection. Here, we make a case for drawing on P. knowlesi as both a human pathogen and an experimental model to lift the roadblock between malaria research and its translation into human health benefits. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. [From malaria parasite point of view--Plasmodium falciparum evolution].

    PubMed

    Zerka, Agata; Kaczmarek, Radosław; Jaśkiewicz, Ewa

    2015-12-31

    Malaria is caused by infection with protozoan parasites belonging to the genus Plasmodium, which have arguably exerted the greatest selection pressure on humans in the history of our species. Besides humans, different Plasmodium parasites infect a wide range of animal hosts, from marine invertebrates to primates. On the other hand, individual Plasmodium species show high host specificity. The extraordinary evolution of Plasmodium probably began when a free-living red algae turned parasitic, and culminated with its ability to thrive inside a human red blood cell. Studies on the African apes generated new data on the evolution of malaria parasites in general and the deadliest human-specific species, Plasmodium falciparum, in particular. Initially, it was hypothesized that P. falciparum descended from the chimpanzee malaria parasite P. reichenowi, after the human and the chimp lineage diverged about 6 million years ago. However, a recently identified new species infecting gorillas, unexpectedly showed similarity to P. falciparum and was therefore named P. praefalciparum. That finding spurred an alternative hypothesis, which proposes that P. falciparum descended from its gorilla rather than chimp counterpart. In addition, the gorilla-to-human host shift may have occurred more recently (about 10 thousand years ago) than the theoretical P. falciparum-P. reichenowi split. One of the key aims of the studies on Plasmodium evolution is to elucidate the mechanisms that allow the incessant host shifting and retaining the host specificity, especially in the case of human-specific species. Thorough understanding of these phenomena will be necessary to design effective malaria treatment and prevention strategies.

  8. Molecular identification of the chitinase genes in Plasmodium relictum.

    PubMed

    Garcia-Longoria, Luz; Hellgren, Olof; Bensch, Staffan

    2014-06-18

    Malaria parasites need to synthesize chitinase in order to go through the peritrophic membrane, which is created around the mosquito midgut, to complete its life cycle. In mammalian malaria species, the chitinase gene comprises either a large or a short copy. In the avian malaria parasites Plasmodium gallinaceum both copies are present, suggesting that a gene duplication in the ancestor to these extant species preceded the loss of either the long or the short copy in Plasmodium parasites of mammals. Plasmodium gallinaceum is not the most widespread and harmful parasite of birds. This study is the first to search for and identify the chitinase gene in one of the most prevalent avian malaria parasites, Plasmodium relictum. Both copies of P. gallinaceum chitinase were used as reference sequences for primer design. Different sequences of Plasmodium spp. were used to build the phylogenetic tree of chitinase gene. The gene encoding for chitinase was identified in isolates of two mitochondrial lineages of P. relictum (SGS1 and GRW4). The chitinase found in these two lineages consists both of the long (PrCHT1) and the short (PrCHT2) copy. The genetic differences found in the long copy of the chitinase gene between SGS1 and GRW4 were higher than the difference observed for the cytochrome b gene. The identification of both copies in P. relictum sheds light on the phylogenetic relationship of the chitinase gene in the genus Plasmodium. Due to its high variability, the chitinase gene could be used to study the genetic population structure in isolates from different host species and geographic regions.

  9. Phylogeny of the malarial genus Plasmodium, derived from rRNA gene sequences.

    PubMed Central

    Escalante, A A; Ayala, F J

    1994-01-01

    Malaria is among mankind's worst scourges, affecting many millions of people, particularly in the tropics. Human malaria is caused by several species of Plasmodium, a parasitic protozoan. We analyze the small subunit rRNA gene sequences of 11 Plasmodium species, including three parasitic to humans, to infer their evolutionary relationships. Plasmodium falciparum, the most virulent of the human species, is closely related to Plasmodium reichenowi, which is parasitic to chimpanzee. The estimated time of divergence of these two Plasmodium species is consistent with the time of divergence (6-10 million years ago) between the human and chimpanzee lineages. The falciparum-reichenowi clade is only remotely related to two other human parasites, Plasmodium malariae and Plasmodium vivax, which are also only remotely related to each other. Thus, the parasitic associations of the Plasmodium species with their human hosts are phylogenetically independent. The remote phylogenetic relationship between the two bird parasites, Plasmodium gallinaceum and Plasmodium lophurae, and any of the human parasites provides no support for the hypothesis that infection by Plasmodium falciparum is a recent acquisition of humans, possibly coincident with the onset of agriculture. PMID:7972067

  10. Replication and maintenance of the Plasmodium falciparum apicoplast genome.

    PubMed

    Milton, Morgan E; Nelson, Scott W

    2016-08-01

    Members of the phylum Apicomplexa are responsible for many devastating diseases including malaria (Plasmodium spp.), toxoplasmosis (Toxoplasma gondii), babesiosis (Babesia bovis), and cyclosporiasis (Cyclospora cayetanensis). Most Apicomplexans contain a unique and essential organelle called the apicoplast. Derived from an ancient chloroplast, the apicoplast replicates and maintains a 35 kilobase (kb) circular genome. Due to its essential nature within the parasite, drugs targeted to proteins involved in DNA replication and repair of the apicoplast should be potent and specific. This review summarizes the current knowledge surrounding the replication and repair of the Plasmodium falciparum apicoplast genome and identifies several putative proteins involved in replication and repair pathways.

  11. Backward bifurcation and optimal control of Plasmodium Knowlesi malaria

    NASA Astrophysics Data System (ADS)

    Abdullahi, Mohammed Baba; Hasan, Yahya Abu; Abdullah, Farah Aini

    2014-07-01

    A deterministic model for the transmission dynamics of Plasmodium Knowlesi malaria with direct transmission is developed. The model is analyzed using dynamical system techniques and it shows that the backward bifurcation occurs for some range of parameters. The model is extended to assess the impact of time dependent preventive (biological and chemical control) against the mosquitoes and vaccination for susceptible humans, while treatment for infected humans. The existence of optimal control is established analytically by the use of optimal control theory. Numerical simulations of the problem, suggest that applying the four control measure can effectively reduce if not eliminate the spread of Plasmodium Knowlesi in a community.

  12. Immunoglobulin A nephropathy associated with Plasmodium falciparum malaria.

    PubMed

    Yoo, Dong Eun; Kim, Jeong Ho; Kie, Jeong Hae; Park, Yoonseon; Chang, Tae Ik; Oh, Hyung Jung; Kim, Seung Jun; Yoo, Tae-Hyun; Choi, Kyu Hun; Kang, Shin-Wook; Han, Seung Hyeok

    2012-04-01

    Glomerulonephritis occurs as a rare form of renal manifestation in Plasmodium falciparum malaria. Herein, we report a case of falciparum malaria-associated IgA nephropathy for the first time. A 49-yr old male who had been to East Africa was diagnosed with Plasmodium falciparum malaria. Microhematuria and proteinuria along with acute kidney injury developed during the course of the disease. Kidney biopsy showed mesangial proliferation and IgA deposits with tubulointerstitial inflammation. Laboratory tests after recovery from malaria showed disappearance of urinary abnormalities and normalization of kidney function. Our findings suggest that malaria infection might be associated with IgA nephropathy.

  13. Blood schizontocidal activity of WR 238605 (Tafenoquine) against Plasmodium cynomolgi and Plasmodium fragile infections in rhesus monkeys.

    PubMed

    Puri, S K; Dutta, G P

    2003-04-01

    A new 8-aminoquinoline antimalarial WR 238605 (Tafenoquine), developed initially as a primaquine alternative for prevention of Plasmodium vivax relapses was evaluated for blood schizontocidal activity against two simian malaria infections namely Plasmodium cynomolgi B and Plasmodium fragile in rhesus monkeys. Treatment with WR 238605 at a dose of 3.16 mg(base)/kg/day x 7 days cured established trophozoite induced infections in monkeys with both these parasites. The lower dose of 1.00 mg/kg/day cured 9 out of 12 monkeys infected with P. cynomolgi B and 10 out of 11 monkeys infected with P. fragile. Primaquine was only partially curative at 10.0 mg(base)/kg/day x 7 dose regimen against both these infections. The potent blood schizontocidal activity of tafenoquine adds to the armoury of antimalarial drugs.

  14. Combating multidrug-resistant Plasmodium falciparum malaria.

    PubMed

    Thu, Aung Myint; Phyo, Aung Pyae; Landier, Jordi; Parker, Daniel M; Nosten, François H

    2017-08-01

    Over the past 50 years, Plasmodium falciparum has developed resistance against all antimalarial drugs used against it: chloroquine, sulphadoxine-pyrimethamine, quinine, piperaquine and mefloquine. More recently, resistance to the artemisinin derivatives and the resulting failure of artemisinin-based combination therapy (ACT) are threatening all major gains made in malaria control. Each time resistance has developed progressively, with delayed clearance of parasites first emerging only in a few regions, increasing in prevalence and geographic range, and then ultimately resulting in the complete failure of that antimalarial. Drawing from this repeated historical chain of events, this article presents context-specific approaches for combating drug-resistant P. falciparum malaria. The approaches begin with a context of drug-sensitive parasites and focus on the prevention of the emergence of drug resistance. Next, the approaches address a scenario in which resistance has emerged and is increasing in prevalence and geographic extent, with interventions focused on disrupting transmission through vector control, early diagnosis and treatment, and the use of new combination therapies. Elimination is also presented as an approach for addressing the imminent failure of all available antimalarials. The final drug resistance context presented is one in which all available antimalarials have failed; leaving only personal protection and the use of new antimalarials (or new combinations of antimalarials) as a viable strategy for dealing with complete resistance. All effective strategies and contexts require a multipronged, holistic approach. © 2017 The Authors. The FEBS Journal published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.

  15. Artemisinin-resistant Plasmodium falciparum malaria

    PubMed Central

    Fairhurst, Rick M.; Dondorp, Arjen M.

    2016-01-01

    For more than five decades, Southeast Asia (SEA) has been fertile ground for the emergence of drug-resistant Plasmodium falciparum malaria. After generating parasites resistant to chloroquine, sulfadoxine, pyrimethamine, quinine, and mefloquine, this region has now spawned parasites resistant to artemisinins – the world's most potent antimalarial drugs. In areas where artemisinin resistance is prevalent, artemisinin combination therapies (ACTs) – the first-line treatments for malaria – are failing fast. This worrisome development threatens to make malaria practically untreatable in SEA, and threatens to compromise global endeavors to eliminate this disease. A recent series of clinical, in-vitro, genomics, and transcriptomics studies in SEA have defined in-vivo and in-vitro phenotypes of artemisinin resistance; identified its causal genetic determinant; explored its molecular mechanism; and assessed its clinical impact. Specifically, these studies have established that artemisinin resistance manifests as slow parasite clearance in patients and increased survival of early ring-stage parasites in vitro; is caused by single nucleotide polymorphisms in the parasite's ‘K13’ gene; is associated with an upregulated “unfolded protein response” pathway that may antagonize the pro-oxidant activity of artemisinins; and selects for partner drug resistance that rapidly leads to ACT failures. In SEA, clinical studies are urgently needed to monitor ACT efficacy where K13 mutations are prevalent; test whether new combinations of currently-available drugs cure ACT failures; and advance new antimalarial compounds through preclinical pipelines and into clinical trials. Intensifying these efforts should help to forestall the spread of artemisinin and partner drug resistance from SEA to Sub-Saharan Africa, where the world's malaria transmission, morbidity, and mortality rates are highest. PMID:27337450

  16. Artemisinin-Resistant Plasmodium falciparum Malaria.

    PubMed

    Fairhurst, Rick M; Dondorp, Arjen M

    2016-06-01

    For more than five decades, Southeast Asia (SEA) has been fertile ground for the emergence of drug-resistant Plasmodium falciparum malaria. After generating parasites resistant to chloroquine, sulfadoxine, pyrimethamine, quinine, and mefloquine, this region has now spawned parasites resistant to artemisinins, the world's most potent antimalarial drugs. In areas where artemisinin resistance is prevalent, artemisinin combination therapies (ACTs)-the first-line treatments for malaria-are failing fast. This worrisome development threatens to make malaria practically untreatable in SEA, and threatens to compromise global endeavors to eliminate this disease. A recent series of clinical, in vitro, genomics, and transcriptomics studies in SEA have defined in vivo and in vitro phenotypes of artemisinin resistance, identified its causal genetic determinant, explored its molecular mechanism, and assessed its clinical impact. Specifically, these studies have established that artemisinin resistance manifests as slow parasite clearance in patients and increased survival of early-ring-stage parasites in vitro; is caused by single nucleotide polymorphisms in the parasite's K13 gene, is associated with an upregulated "unfolded protein response" pathway that may antagonize the pro-oxidant activity of artemisinins, and selects for partner drug resistance that rapidly leads to ACT failures. In SEA, clinical studies are urgently needed to monitor ACT efficacy where K13 mutations are prevalent, test whether new combinations of currently available drugs cure ACT failures, and advance new antimalarial compounds through preclinical pipelines and into clinical trials. Intensifying these efforts should help to forestall the spread of artemisinin and partner drug resistance from SEA to sub-Saharan Africa, where the world's malaria transmission, morbidity, and mortality rates are highest.

  17. Unique properties of Plasmodium falciparum porphobilinogen deaminase.

    PubMed

    Nagaraj, Viswanathan Arun; Arumugam, Rajavel; Gopalakrishnan, Bulusu; Jyothsna, Yeleswarapu Sri; Rangarajan, Pundi N; Padmanaban, Govindarajan

    2008-01-04

    The hybrid pathway for heme biosynthesis in the malarial parasite proposes the involvement of parasite genome-coded enzymes of the pathway localized in different compartments such as apicoplast, mitochondria, and cytosol. However, knowledge on the functionality and localization of many of these enzymes is not available. In this study, we demonstrate that porphobilinogen deaminase encoded by the Plasmodium falciparum genome (PfPBGD) has several unique biochemical properties. Studies carried out with PfPBGD partially purified from parasite membrane fraction, as well as recombinant PfPBGD lacking N-terminal 64 amino acids expressed and purified from Escherichia coli cells (DeltaPfPBGD), indicate that both the proteins are catalytically active. Surprisingly, PfPBGD catalyzes the conversion of porphobilinogen to uroporphyrinogen III (UROGEN III), indicating that it also possesses uroporphyrinogen III synthase (UROS) activity, catalyzing the next step. This obviates the necessity to have a separate gene for UROS that has not been so far annotated in the parasite genome. Interestingly, DeltaPfP-BGD gives rise to UROGEN III even after heat treatment, although UROS from other sources is known to be heat-sensitive. Based on the analysis of active site residues, a DeltaPfPBGDL116K mutant enzyme was created and the specific activity of this recombinant mutant enzyme is 5-fold higher than DeltaPfPBGD. More interestingly, DeltaPfPBGDL116K catalyzes the formation of uroporphyrinogen I (UROGEN I) in addition to UROGEN III, indicating that with increased PBGD activity the UROS activity of PBGD may perhaps become rate-limiting, thus leading to non-enzymatic cyclization of preuroporphyrinogen to UROGEN I. PfPBGD is localized to the apicoplast and is catalytically very inefficient compared with the host red cell enzyme.

  18. Plasmodium falciparum glutaredoxin-like proteins.

    PubMed

    Deponte, Marcel; Becker, Katja; Rahlfs, Stefan

    2005-01-01

    Glutaredoxin-like proteins form a new subgroup of glutaredoxins with a serine replacing the second cysteine in the CxxC-motif of the active site. Yeast Grx5 is the only glutaredoxin-like protein studied biochemically so far. We identified and cloned three genes encoding glutaredoxin-like proteins from the malaria parasite Plasmodium falciparum (Pf Glp1, Pf Glp2, and Pf Glp3) containing a conserved cysteine in the CGFS-, CKFS-, and CKYS-motif, respectively. Here, we describe biochemical properties of Pf Glp1 and Pf Glp2. Cys 99, the only cysteine residue in Pf Glp1, has a pK(a) value as low as 5.5 and is able to mediate covalent homodimerization. Monomeric and dimeric Pf Glp1 react with GSSG and GSH, respectively. Pf Glp2 is monomeric and both of its cysteine residues can be glutathionylated. Molecular models reveal a thioredoxin fold for the putative C-terminal domain of Pf Glp1, Pf Glp2, and Pf Glp3, as well as conserved residues presumably required for glutathione binding. However, Pf Glp1 and Pf Glp2 neither possess activity in a classical glutaredoxin assay nor display activity as glutathione peroxidase or glutathione S-transferase. Mutation of Ser 102 in the CGFS-motif of Pf Glp1 to cysteine did not generate glutaredoxin activity either. We conclude that, despite their ability to react with glutathione, glutaredoxin-like proteins are a mechanistically and functionally heterogeneous group with only little similarities to canonical glutaredoxins.

  19. Potentiation of activity of diaphenylsulfone and pyrimethamine against Plasmodium gallinaceum and Plasmodium cynomolgi bastianellii*

    PubMed Central

    Basu, P. C.; Singh, N. N.; Singh, Naunihal

    1964-01-01

    In view of the fact that diaphenylsulfone has been shown to have low schizontocidal activity against Plasmodium gallinaceum and to lead to resistance in strains of P. cynomolgi, investigations were undertaken into the joint action of diaphenylsulfone and pyrimethamine against P. gallinaceum in chicks and P. cynomolgi bastianellii in monkeys. These drugs were assayed separately and in various combinations. It was found that at certain dose levels combination of the two drugs led to potentiation of their plasmocidal activity. On the other hand, this synergistic effect was not noted with combinations containing lower dosages of either drug; with these, a simple additive effect occurred. The authors suggest that the two drugs probably act on the same metabolic pathway but that their points of attack may be different. They note also that there was a difference in the response of P. gallinaceum in chicks and of P. cynomolgi bastianellii in monkeys to the combined use of the two drugs. PMID:14278006

  20. Distribution of two species of malaria, Plasmodium falciparum and Plasmodium vivax, on Lombok Island, Indonesia.

    PubMed

    Nagao, Yoshiro; Dachlan, Yoes Prijatna; Soedarto; Hidajati, Sri; Yotopranoto, Subagyo; Kusmartisnawati; Subekti, Sri; Ideham, Bariah; Tsuda, Yoshio; Kawabata, Masato; Takagi, Masahiro; Looareesuwan, Somchai

    2003-09-01

    Medical and entomological surveys were conducted to determine the risk factors of Plasmodium falciparum and P. vivax infections on Lombok Island, Indonesia, to find the risk factors and the main mosquito vectors for each malaria. Multivariate longitudinal analysis demonstrated two significant risk factors for infection with P. falciparum: disappearance of P. vivax parasitemia (p<0.001) and a specific study site (p<0.001). In contrast, younger age (p=0.024) and the interpolated virtual density of An. subpictus (p=0.041) were significantly associated with increased risk of infection with P. vivax. Thus, it seems that the distribution of P. vivax was determined largely by the presence of An. subpictus, whilst that of P. falciparum was influenced by antagonism with P. vivax. This result shows the importance of following-up treated P. vivax patients to identify recrudescence of P. falciparum in this area.

  1. Plasmodium falciparum and Plasmodium vivax specific lactate dehydrogenase: genetic polymorphism study from Indian isolates.

    PubMed

    Keluskar, Priyadarshan; Singh, Vineeta; Gupta, Purva; Ingle, Sanjay

    2014-08-01

    Control and eradication of malaria is hindered by the acquisition of drug resistance by Plasmodium species. This has necessitated a persistent search for novel drugs and more efficient targets. Plasmodium species specific lactate dehydrogenase is one of the potential therapeutic and diagnostic targets, because of its indispensable role in endoerythrocytic stage of the parasite. A target molecule that is highly conserved in the parasite population can be more effectively used in diagnostics and therapeutics, hence, in the present study polymorphism in PfLDH (Plasmodiumfalciparum specific LDH) and PvLDH (Plasmodiumvivax specific LDH) genes was analyzed using PCR-single strand confirmation polymorphism (PCR-SSCP) and sequencing. Forty-six P. falciparum and thirty-five P. vivax samples were screened from different states of India. Our findings have revealed presence of a single PfLDH genotype and six PvLDH genotypes among the studied samples. Interestingly, along with synonymous substitutions, nonsynonymous substitutions were reported to be present for the first time in the PvLDH genotypes. Further, through amino acid sequence alignment and homology modeling studies we observed that the catalytic residues were conserved in all PvLDH genotypes and the nonsynonymous substitutions have not altered the enzyme structure significantly. Evolutionary genetics studies have confirmed that PfLDH and PvLDH loci are under strong purifying selection. Phylogenetic analysis of the pLDH gene sequences revealed that P. falciparum compared to P. vivax, has recent origin. The study therefore supports PfLDH and PvLDH as suitable therapeutic and diagnostic targets as well as phylogenetic markers to understand the genealogy of malaria species.

  2. Drug resistance associated genetic polymorphisms in Plasmodium falciparum and Plasmodium vivax collected in Honduras, Central America.

    PubMed

    Jovel, Irina T; Mejía, Rosa E; Banegas, Engels; Piedade, Rita; Alger, Jackeline; Fontecha, Gustavo; Ferreira, Pedro E; Veiga, Maria I; Enamorado, Irma G; Bjorkman, Anders; Ursing, Johan

    2011-12-19

    In Honduras, chloroquine and primaquine are recommended and still appear to be effective for treatment of Plasmodium falciparum and Plasmodium vivax malaria. The aim of this study was to determine the proportion of resistance associated genetic polymorphisms in P. falciparum and P. vivax collected in Honduras. Blood samples were collected from patients seeking medical attention at the Hospital Escuela in Tegucigalpa from 2004 to 2006 as well as three regional hospitals, two health centres and one regional laboratory during 2009. Single nucleotide polymorphisms in P. falciparum chloroquine resistance transporter (pfcrt), multidrug resistance 1 (pfmdr1), dihydrofolate reductase (pfdhfr) and dihydropteroate synthase (pfdhps) genes and in P. vivax multidrug resistance 1 (pvmdr1) and dihydrofolate reductase (pvdhfr) genes were detected using PCR based methods. Thirty seven P. falciparum and 64 P. vivax samples were collected. All P. falciparum infections acquired in Honduras carried pfcrt, pfmdr1, pfdhps and pfdhfr alleles associated with chloroquine, amodiaquine and sulphadoxine-pyrimethamine sensitivity only. One patient with parasites acquired on a Pacific Island had pfcrt 76 T and pfmdr1 86Y alleles. That patient and a patient infected in West Africa had pfdhfr 51I, 59 R and 108 N alleles. Pvmdr1 976 F was found in 7/37 and two copies of pvmdr1 were found in 1/37 samples. Pvdhfr 57 L + 58 R was observed in 2/57 samples. The results indicate that P. falciparum from Honduras remain sensitive to chloroquine and sulphadoxine-pyrimethamine. This suggests that chloroquine and sulphadoxine-pyrimethamine should be efficacious for treatment of uncomplicated P. falciparum malaria, supporting current national treatment guidelines. However, genetic polymorphisms associated with chloroquine and sulphadoxine-pyrimethamine tolerance were detected in local P. vivax and imported P. falciparum infections. Continuous monitoring of the prevalence of drug resistant/tolerant P

  3. Drug resistance associated genetic polymorphisms in Plasmodium falciparum and Plasmodium vivax collected in Honduras, Central America

    PubMed Central

    2011-01-01

    Background In Honduras, chloroquine and primaquine are recommended and still appear to be effective for treatment of Plasmodium falciparum and Plasmodium vivax malaria. The aim of this study was to determine the proportion of resistance associated genetic polymorphisms in P. falciparum and P. vivax collected in Honduras. Methods Blood samples were collected from patients seeking medical attention at the Hospital Escuela in Tegucigalpa from 2004 to 2006 as well as three regional hospitals, two health centres and one regional laboratory during 2009. Single nucleotide polymorphisms in P. falciparum chloroquine resistance transporter (pfcrt), multidrug resistance 1 (pfmdr1), dihydrofolate reductase (pfdhfr) and dihydropteroate synthase (pfdhps) genes and in P. vivax multidrug resistance 1 (pvmdr1) and dihydrofolate reductase (pvdhfr) genes were detected using PCR based methods. Results Thirty seven P. falciparum and 64 P. vivax samples were collected. All P. falciparum infections acquired in Honduras carried pfcrt, pfmdr1, pfdhps and pfdhfr alleles associated with chloroquine, amodiaquine and sulphadoxine-pyrimethamine sensitivity only. One patient with parasites acquired on a Pacific Island had pfcrt 76 T and pfmdr1 86Y alleles. That patient and a patient infected in West Africa had pfdhfr 51I, 59 R and 108 N alleles. Pvmdr1 976 F was found in 7/37 and two copies of pvmdr1 were found in 1/37 samples. Pvdhfr 57 L + 58 R was observed in 2/57 samples. Conclusion The results indicate that P. falciparum from Honduras remain sensitive to chloroquine and sulphadoxine-pyrimethamine. This suggests that chloroquine and sulphadoxine-pyrimethamine should be efficacious for treatment of uncomplicated P. falciparum malaria, supporting current national treatment guidelines. However, genetic polymorphisms associated with chloroquine and sulphadoxine-pyrimethamine tolerance were detected in local P. vivax and imported P. falciparum infections. Continuous monitoring of the prevalence

  4. Modelling the incidence of Plasmodium vivax and Plasmodium falciparum malaria in Afghanistan 2006-2009.

    PubMed

    Alegana, Victor A; Wright, Jim A; Nahzat, Sami M; Butt, Waqar; Sediqi, Amad W; Habib, Naeem; Snow, Robert W; Atkinson, Peter M; Noor, Abdisalan M

    2014-01-01

    Identifying areas that support high malaria risks and where populations lack access to health care is central to reducing the burden in Afghanistan. This study investigated the incidence of Plasmodium vivax and Plasmodium falciparum using routine data to help focus malaria interventions. To estimate incidence, the study modelled utilisation of the public health sector using fever treatment data from the 2012 national Malaria Indicator Survey. A probabilistic measure of attendance was applied to population density metrics to define the proportion of the population within catchment of a public health facility. Malaria data were used in a Bayesian spatio-temporal conditional-autoregressive model with ecological or environmental covariates, to examine the spatial and temporal variation of incidence. From the analysis of healthcare utilisation, over 80% of the population was within 2 hours' travel of the nearest public health facility, while 64.4% were within 30 minutes' travel. The mean incidence of P. vivax in 2009 was 5.4 (95% Crl 3.2-9.2) cases per 1000 population compared to 1.2 (95% Crl 0.4-2.9) cases per 1000 population for P. falciparum. P. vivax peaked in August while P. falciparum peaked in November. 32% of the estimated 30.5 million people lived in regions where annual incidence was at least 1 case per 1,000 population of P. vivax; 23.7% of the population lived in areas where annual P. falciparum case incidence was at least 1 per 1000. This study showed how routine data can be combined with household survey data to model malaria incidence. The incidence of both P. vivax and P. falciparum in Afghanistan remain low but the co-distribution of both parasites and the lag in their peak season provides challenges to malaria control in Afghanistan. Future improved case definition to determine levels of imported risks may be useful for the elimination ambitions in Afghanistan.

  5. Modelling the Incidence of Plasmodium vivax and Plasmodium falciparum Malaria in Afghanistan 2006–2009

    PubMed Central

    Alegana, Victor A.; Wright, Jim A.; Nahzat, Sami M.; Butt, Waqar; Sediqi, Amad W.; Habib, Naeem; Snow, Robert W.; Atkinson, Peter M.; Noor, Abdisalan M.

    2014-01-01

    Background Identifying areas that support high malaria risks and where populations lack access to health care is central to reducing the burden in Afghanistan. This study investigated the incidence of Plasmodium vivax and Plasmodium falciparum using routine data to help focus malaria interventions. Methods To estimate incidence, the study modelled utilisation of the public health sector using fever treatment data from the 2012 national Malaria Indicator Survey. A probabilistic measure of attendance was applied to population density metrics to define the proportion of the population within catchment of a public health facility. Malaria data were used in a Bayesian spatio-temporal conditional-autoregressive model with ecological or environmental covariates, to examine the spatial and temporal variation of incidence. Findings From the analysis of healthcare utilisation, over 80% of the population was within 2 hours’ travel of the nearest public health facility, while 64.4% were within 30 minutes’ travel. The mean incidence of P. vivax in 2009 was 5.4 (95% Crl 3.2–9.2) cases per 1000 population compared to 1.2 (95% Crl 0.4–2.9) cases per 1000 population for P. falciparum. P. vivax peaked in August while P. falciparum peaked in November. 32% of the estimated 30.5 million people lived in regions where annual incidence was at least 1 case per 1,000 population of P. vivax; 23.7% of the population lived in areas where annual P. falciparum case incidence was at least 1 per 1000. Conclusion This study showed how routine data can be combined with household survey data to model malaria incidence. The incidence of both P. vivax and P. falciparum in Afghanistan remain low but the co-distribution of both parasites and the lag in their peak season provides challenges to malaria control in Afghanistan. Future improved case definition to determine levels of imported risks may be useful for the elimination ambitions in Afghanistan. PMID:25033452

  6. Plasmodium vivax Populations Are More Genetically Diverse and Less Structured than Sympatric Plasmodium falciparum Populations

    PubMed Central

    Jennison, Charlie; Arnott, Alicia; Tessier, Natacha; Tavul, Livingstone; Koepfli, Cristian; Felger, Ingrid; Siba, Peter M.; Reeder, John C.; Bahlo, Melanie; Mueller, Ivo; Barry, Alyssa E.

    2015-01-01

    Introduction The human malaria parasite, Plasmodium vivax, is proving more difficult to control and eliminate than Plasmodium falciparum in areas of co-transmission. Comparisons of the genetic structure of sympatric parasite populations may provide insight into the mechanisms underlying the resilience of P. vivax and can help guide malaria control programs. Methodology/Principle findings P. vivax isolates representing the parasite populations of four areas on the north coast of Papua New Guinea (PNG) were genotyped using microsatellite markers and compared with previously published microsatellite data from sympatric P. falciparum isolates. The genetic diversity of P. vivax (He = 0.83–0.85) was higher than that of P. falciparum (He = 0.64–0.77) in all four populations. Moderate levels of genetic differentiation were found between P. falciparum populations, even over relatively short distances (less than 50 km), with 21–28% private alleles and clear geospatial genetic clustering. Conversely, very low population differentiation was found between P. vivax catchments, with less than 5% private alleles and no genetic clustering observed. In addition, the effective population size of P. vivax (30353; 13043–69142) was larger than that of P. falciparum (18871; 8109–42986). Conclusions/Significance Despite comparably high prevalence, P. vivax had higher diversity and a panmictic population structure compared to sympatric P. falciparum populations, which were fragmented into subpopulations. The results suggest that in comparison to P. falciparum, P. vivax has had a long-term large effective population size, consistent with more intense and stable transmission, and limited impact of past control and elimination efforts. This underlines suggestions that more intensive and sustained interventions will be needed to control and eventually eliminate P. vivax. This research clearly demonstrates how population genetic analyses can reveal deeper insight into transmission

  7. Severe Plasmodium falciparum and Plasmodium vivax malaria among adults at Kassala Hospital, eastern Sudan

    PubMed Central

    2013-01-01

    Background There have been few published reports on severe Plasmodium falciparum and Plasmodium vivax malaria among adults in Africa. Methods Clinical pattern/manifestations of severe P. falciparum and P. vivax (according to World Health Organization 2000 criteria) were described in adult patients admitted to Kassala Hospital, eastern Sudan. Results A total of 139 adult patients (80 males, 57.6%) with a mean (SD) age of 37.2 (1.5) years presented with severe P. falciparum (113, 81.3%) or P. vivax (26, 18.7%) malaria. Manifestations among the 139 patients included hypotension (38, 27.3%), cerebral malaria (23, 16.5%), repeated convulsions (18, 13.0%), hypoglycaemia (15, 10.8%), hyperparasitaemia (14, 10.1%), jaundice (14, 10.1%), severe anaemia (10, 7.2%), bleeding (six, 4.3%), renal impairment (one, 0.7%) and more than one criteria (27, 19.4%). While the geometric mean of the parasite count was significantly higher in patients with severe P. vivax than with severe P. falciparum malaria (5,934.2 vs 13,906.6 asexual stage parasitaemia per μL, p = 0.013), the different disease manifestations were not significantly different between patients with P. falciparum or P. vivax malaria. Three patients (2.2%) died due to severe P. falciparum malaria. One had cerebral malaria, the second had renal impairment, jaundice and hypoglycaemia, and the third had repeated convulsions and hypotension. Conclusions Severe malaria due to P. falciparum and P. vivax malaria is an existing entity among adults in eastern Sudan. Patients with severe P. falciparum and P. vivax develop similar disease manifestations. PMID:23634728

  8. Malaria morbidity in Papua Indonesia, an area with multidrug resistant Plasmodium vivax and Plasmodium falciparum

    PubMed Central

    Karyana, Muhammad; Burdarm, Lenny; Yeung, Shunmay; Kenangalem, Enny; Wariker, Noah; Maristela, Rilia; Umana, Ketut Gde; Vemuri, Ram; Okoseray, Maurits J; Penttinen, Pasi M; Ebsworth, Peter; Sugiarto, Paulus; Anstey, Nicholas M; Tjitra, Emiliana; Price, Richard N

    2008-01-01

    Background Multidrug resistance has emerged to both Plasmodium vivax and Plasmodium falciparum and yet the comparative epidemiology of these infections is poorly defined. Methods All laboratory-confirmed episodes of malaria in Timika, Papua, Indonesia, presenting to community primary care clinics and an inpatient facility were reviewed over a two-year period. In addition information was gathered from a house-to-house survey to quantify the prevalence of malaria and treatment-seeking behaviour of people with fever. Results Between January 2004 and December 2005, 99,158 laboratory-confirmed episodes of malaria were reported, of which 58% (57,938) were attributable to P. falciparum and 37% (36,471) to P. vivax. Malaria was most likely to be attributable to pure P. vivax in children under one year of age (55% 2,684/4,889). In the household survey, the prevalence of asexual parasitaemia was 7.5% (290/3,890) for P. falciparum and 6.4% (248/3,890) for P. vivax. The prevalence of P. falciparum infection peaked in young adults aged 15–25 years (9.8% 69/707), compared to P. vivax infection which peaked in children aged 1 to 4 years (9.5% 61/642). Overall 35% (1,813/5,255) of people questioned reported a febrile episode in the preceding month. Of the 60% of people who were estimated to have had malaria, only 39% would have been detected by the surveillance network. The overall incidence of malaria was therefore estimated as 876 per 1,000 per year (Range: 711–906). Conclusion In this region of multidrug-resistant P. vivax and P. falciparum, both species are associated with substantial morbidity, but with significant differences in the age-related risk of infection. PMID:18673572

  9. Origin of the human malaria parasite Plasmodium falciparum in gorillas

    PubMed Central

    Liu, Weimin; Li, Yingying; Learn, Gerald H.; Rudicell, Rebecca S.; Robertson, Joel D.; Keele, Brandon F.; Ndjango, Jean-Bosco N.; Sanz, Crickette M.; Morgan, David B.; Locatelli, Sabrina; Gonder, Mary K.; Kranzusch, Philip J.; Walsh, Peter D.; Delaporte, Eric; Mpoudi-Ngole, Eitel; Georgiev, Alexander V.; Muller, Martin N.; Shaw, George M.; Peeters, Martine; Sharp, Paul M.; Rayner, Julian C.; Hahn, Beatrice H.

    2010-01-01

    Plasmodium falciparum is the most prevalent and lethal of the malaria parasites infecting humans, yet the origin and evolutionary history of this important pathogen remain controversial. Here, we developed a novel polymerase chain reaction based single genome amplification strategy to identify and characterize Plasmodium spp. DNA sequences in fecal samples of wild-living apes. Among nearly 3,000 specimens collected from field sites throughout central Africa, we found Plasmodium infection in chimpanzees (Pan troglodytes) and western gorillas (Gorilla gorilla), but not in eastern gorillas (Gorilla beringei) or bonobos (Pan paniscus). Ape plasmodial infections were highly prevalent, widely distributed, and almost always comprised of mixed parasite species. Analysis of more than 1,100 mitochondrial, apicoplast and nuclear gene sequences from chimpanzees and gorillas revealed that 99% grouped within one of six host-specific lineages representing distinct Plasmodium species within the subgenus Laverania. One of these from western gorillas was comprised of parasites that were nearly identical to P. falciparum. In phylogenetic analyses of full-length mitochondrial sequences, human P. falciparum formed a monophyletic lineage within the gorilla parasite radiation. These findings indicate that P. falciparum is of gorilla and not of chimpanzee, bonobo or ancient human origin. PMID:20864995

  10. Multiple pathways for Plasmodium ookinete invasion of the mosquito midgut

    PubMed Central

    Vega-Rodríguez, Joel; Ghosh, Anil K.; Kanzok, Stefan M.; Dinglasan, Rhoel R.; Wang, Sibao; Bongio, Nicholas J.; Kalume, Dario E.; Miura, Kazutoyo; Long, Carole A.; Pandey, Akhilesh; Jacobs-Lorena, Marcelo

    2014-01-01

    Plasmodium ookinete invasion of the mosquito midgut is a crucial step of the parasite life cycle but little is known about the molecular mechanisms involved. Previously, a phage display peptide library screen identified SM1, a peptide that binds to the mosquito midgut epithelium and inhibits ookinete invasion. SM1 was characterized as a mimotope of an ookinete surface enolase and SM1 presumably competes with enolase, the presumed ligand, for binding to a putative midgut receptor. Here we identify a mosquito midgut receptor that binds both SM1 and ookinete surface enolase, termed “enolase-binding protein” (EBP). Moreover, we determined that Plasmodium berghei parasites are heterogeneous for midgut invasion, as some parasite clones are strongly inhibited by SM1 whereas others are not. The SM1-sensitive parasites required the mosquito EBP receptor for midgut invasion whereas the SM1-resistant parasites invaded the mosquito midgut independently of EBP. These experiments provide evidence that Plasmodium ookinetes can invade the mosquito midgut by alternate pathways. Furthermore, another peptide from the original phage display screen, midgut peptide 2 (MP2), strongly inhibited midgut invasion by P. berghei (SM1-sensitive and SM1-resistant) and Plasmodium falciparum ookinetes, suggesting that MP2 binds to a separate, universal receptor for midgut invasion. PMID:24474798

  11. Plasmodium cellular effector mechanisms and the hepatic microenvironment

    PubMed Central

    Frevert, Ute; Krzych, Urszula

    2015-01-01

    Plasmodium falciparum malaria remains one of the most serious health problems globally. Immunization with attenuated parasites elicits multiple cellular effector mechanisms capable of eliminating Plasmodium liver stages. However, malaria liver stage (LS) immunity is complex and the mechanisms effector T cells use to locate the few infected hepatocytes in the large liver in order to kill the intracellular LS parasites remain a mystery to date. Here, we review our current knowledge on the behavior of CD8 effector T cells in the hepatic microvasculature, in malaria and other hepatic infections. Taking into account the unique immunological and lymphogenic properties of the liver, we discuss whether classical granule-mediated cytotoxicity might eliminate infected hepatocytes via direct cell contact or whether cytokines might operate without cell–cell contact and kill Plasmodium LSs at a distance. A thorough understanding of the cellular effector mechanisms that lead to parasite death hence sterile protection is a prerequisite for the development of a successful malaria vaccine to protect the 40% of the world’s population currently at risk of Plasmodium infection. PMID:26074888

  12. Drug Evaluation in the Plasmodium falciparum - Aotus Model

    DTIC Science & Technology

    1984-09-01

    R. N., Harper, J. S. Ill, Davidson D. E. Jr., Escajadillo , A. and Christensen H. A. Comparison of Plasmodium falciparum infec- tions in Panamanian...CONTRACTS R. N. Rossan, Ph. D. D. C. Baerg, Ph. D. J. C. Harper, VMD A. Escajadillo , DVM H. A. Christensen, Ph. D L. Martinez F. Durham G. Ci

  13. Genomics and epigenetics of sexual commitment in Plasmodium.

    PubMed

    Bechtsi, D P; Waters, A P

    2017-06-01

    Malaria is the disease caused by the apicomplexan parasites belonging to the genus Plasmodium. Expanding our arsenal to include transmission-blocking agents in our fight against malaria is becoming increasingly important. Such an implementation requires detailed understanding of the biology of the Plasmodium life cycle stages that are transmissible. Plasmodium gametocytes are the only parasite stage that can be transmitted to the mosquito vector and are the product of sexual development in a small percentage of parasites that continually proliferate in host blood. The critical decision made by asexual erythrocytic stages to cease further proliferation and differentiate into gametocytes, as well as the first steps they take into maturity, have long remained unknown. Recent studies have contributed to a breakthrough in our understanding of this branch point in development. In this review, we will discuss the findings that have allowed us to make this major leap forward in our knowledge of sexual commitment in Plasmodium. We will further propose a model for the mechanism triggering the switch to sexual development, constructed around the proteins currently known to regulate this process. Further insight into sexual commitment and gametocyte development will help identify targets for the development of transmission-blocking malaria therapies. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  14. Source identification of autochthonous-introduced Plasmodium vivax Malaria, Spain.

    PubMed

    Barrado, Laura; Ezpeleta, Carmen; Rubio, José Miguel; Martín, Carmen; Azcona, José Manuel; Arteaga, Miren; Beristain, Xabier; Navascués, Ana; Ongay, Eva; Castilla, Jesús

    2017-02-01

    In 2014, an autochthonous case of introduced malaria caused by Plasmodium vivax was identified in Spain. The strain that infected this patient was identical to that of a prior imported case from Pakistan. This is the first case where the source of infection could be identified since elimination in Spain.

  15. New Strategies for Drug Discovery and Development for Plasmodium Falciparum

    DTIC Science & Technology

    2000-01-01

    research working in concert with one another. The goal of this work is to use a molecular genetic approach both in the identification of new drug targets...analysis of critical genes in the Plasmodium falciparum for their role in drug resistance and as potential new drug targets using both the homologous P. falciparum system and the heterologous yeast system.

  16. New Strategies for Drug Discovery and Development for Plasmodium falciparum

    DTIC Science & Technology

    2001-01-01

    research working in concert with one another. The goal of this work is to use a molecular genetic approach both in the identification of new drug targets and...Plasmodium falciparum for their role in drug resistance and as potential new drug targets, including the analysis of gene expression in response to

  17. Plasmodium knowlesi infection in humans, Cambodia, 2007-2010.

    PubMed

    Khim, Nimol; Siv, Sovannaroth; Kim, Saorin; Mueller, Tara; Fleischmann, Erna; Singh, Balbir; Divis, Paul Cliff Simon; Steenkeste, Nicolas; Duval, Linda; Bouchier, Christiane; Duong, Socheat; Ariey, Frederic; Menard, Didier

    2011-10-01

    Two cases of Plasmodium knowlesi infection in humans were identified in Cambodia by 3 molecular detection assays and sequencing. This finding confirms the widespread distribution of P. knowlesi malaria in humans in Southeast Asia. Further wide-scale studies are required to assess the public health relevance of this zoonotic malaria parasite.

  18. Plasmodium knowlesi Infection in Humans, Cambodia, 2007–2010

    PubMed Central

    Khim, Nimol; Siv, Sovannaroth; Kim, Saorin; Mueller, Tara; Fleischmann, Erna; Singh, Balbir; Divis, Paul Cliff Simon; Steenkeste, Nicolas; Duval, Linda; Bouchier, Christiane; Duong, Socheat; Ariey, Frederic

    2011-01-01

    Two cases of Plasmodium knowlesi infection in humans were identified in Cambodia by 3 molecular detection assays and sequencing. This finding confirms the widespread distribution of P. knowlesi malaria in humans in Southeast Asia. Further wide-scale studies are required to assess the public health relevance of this zoonotic malaria parasite. PMID:22000366

  19. Structural Differences Explain Diverse Functions of Plasmodium Actins

    PubMed Central

    Vahokoski, Juha; Martinez, Silvia Muñico; Ignatev, Alexander; Lepper, Simone; Frischknecht, Friedrich; Sidén-Kiamos, Inga; Sachse, Carsten; Kursula, Inari

    2014-01-01

    Actins are highly conserved proteins and key players in central processes in all eukaryotic cells. The two actins of the malaria parasite are among the most divergent eukaryotic actins and also differ from each other more than isoforms in any other species. Microfilaments have not been directly observed in Plasmodium and are presumed to be short and highly dynamic. We show that actin I cannot complement actin II in male gametogenesis, suggesting critical structural differences. Cryo-EM reveals that Plasmodium actin I has a unique filament structure, whereas actin II filaments resemble canonical F-actin. Both Plasmodium actins hydrolyze ATP more efficiently than α-actin, and unlike any other actin, both parasite actins rapidly form short oligomers induced by ADP. Crystal structures of both isoforms pinpoint several structural changes in the monomers causing the unique polymerization properties. Inserting the canonical D-loop to Plasmodium actin I leads to the formation of long filaments in vitro. In vivo, this chimera restores gametogenesis in parasites lacking actin II, suggesting that stable filaments are required for exflagellation. Together, these data underline the divergence of eukaryotic actins and demonstrate how structural differences in the monomers translate into filaments with different properties, implying that even eukaryotic actins have faced different evolutionary pressures and followed different paths for developing their polymerization properties. PMID:24743229

  20. Molecular Surveillance for Multidrug-Resistant Plasmodium falciparum, Cambodia

    PubMed Central

    Shah, Naman K.; Alker, Alisa P.; Sem, Rithy; Susanti, Agustina Ika; Muth, Sinuon; Maguire, Jason D.; Duong, Socheat; Ariey, Frederic; Meshnick, Steven R.

    2008-01-01

    We conducted surveillance for multidrug-resistant Plasmodium falciparum in Cambodia during 2004–2006 by assessing molecular changes in pfmdr1. The high prevalence of isolates with multiple pfmdr1 copies found in western Cambodia near the Thai border, where artesunate–mefloquine therapy failures occur, contrasts with isolates from eastern Cambodia, where this combination therapy remains highly effective. PMID:18826834

  1. 21 CFR 866.3402 - Plasmodium species antigen detection assays.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... is a device that employs antibodies for the detection of specific malaria parasite antigens... with malaria infection. The detection of these antigens aids in the clinical laboratory diagnosis of malaria caused by the four malaria species capable of infecting humans: Plasmodium falciparum,...

  2. 21 CFR 866.3402 - Plasmodium species antigen detection assays.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... is a device that employs antibodies for the detection of specific malaria parasite antigens... with malaria infection. The detection of these antigens aids in the clinical laboratory diagnosis of malaria caused by the four malaria species capable of infecting humans: Plasmodium falciparum,...

  3. 21 CFR 866.3402 - Plasmodium species antigen detection assays.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... is a device that employs antibodies for the detection of specific malaria parasite antigens... with malaria infection. The detection of these antigens aids in the clinical laboratory diagnosis of malaria caused by the four malaria species capable of infecting humans: Plasmodium falciparum,...

  4. 21 CFR 866.3402 - Plasmodium species antigen detection assays.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... is a device that employs antibodies for the detection of specific malaria parasite antigens... with malaria infection. The detection of these antigens aids in the clinical laboratory diagnosis of malaria caused by the four malaria species capable of infecting humans: Plasmodium falciparum,...

  5. 21 CFR 866.3402 - Plasmodium species antigen detection assays.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... is a device that employs antibodies for the detection of specific malaria parasite antigens... with malaria infection. The detection of these antigens aids in the clinical laboratory diagnosis of malaria caused by the four malaria species capable of infecting humans: Plasmodium falciparum,...

  6. Molecular make-up of the Plasmodium parasitophorous vacuolar membrane.

    PubMed

    Spielmann, Tobias; Montagna, Georgina N; Hecht, Leonie; Matuschewski, Kai

    2012-10-01

    Plasmodium, the causative agent of malaria, is an obligate, intracellular, eukaryotic cell that invades, replicates, and differentiates within hepatocytes and erythrocytes. Inside a host cell, a second membrane delineates the developing pathogen in addition to the parasite plasma membrane, resulting in a distinct cellular compartment, termed parasitophorous vacuole (PV). The PV membrane (PVM) constitutes the parasite-host cell interface and is likely central to nutrient acquisition, host cell remodeling, waste disposal, environmental sensing, and protection from innate defense. Over the past two decades, a number of parasite-encoded PVM proteins have been identified. They include multigene families and protein complexes, such as early-transcribed membrane proteins (ETRAMPs) and the Plasmodium translocon for exported proteins (PTEX). Nearly all Plasmodium PVM proteins are restricted to this genus and display transient and stage-specific expression. Here, we provide an overview of the PVM proteins of Plasmodium blood and liver stages. Biochemical and experimental genetics data suggest that some PVM proteins are ideal targets for novel anti-malarial intervention strategies.

  7. Exploring Anopheles gut bacteria for Plasmodium blocking activity

    PubMed Central

    Bahia, Ana C; Dong, Yuemei; Blumberg, Benjamin J; Mlambo, Godfree; Tripathi, Abhai; BenMarzouk-Hidalgo, Omar J; Chandra, Ramesh; Dimopoulos, George

    2014-01-01

    SUMMARY Malaria parasite transmission requires the successful development of Plasmodium gametocytes into flagellated microgametes upon mosquito blood ingestion, and the subsequent fertilization of microgametes and macrogametes for the development of motile zygotes, called ookinetes, which invade and transverse the Anopheles vector mosquito midgut at around 18-36 h after blood ingestion. Within the mosquito midgut, the malaria parasite has to withstand the mosquito's innate immune response and the detrimental effect of its commensal bacterial flora. We have assessed the midgut colonization capacity of 5 gut bacterial isolates from field-derived, and 2 from laboratory colony, mosquitoes and their effect on Plasmodium development in vivo and in vitro, along with their impact on mosquito survival. Some bacterial isolates activated the mosquito's immune system, affected the mosquito's life span, and were capable of blocking Plasmodium development. We have also shown that the ability of these bacteria to inhibit the parasites is likely to involve different mechanisms and factors. A Serratia marcescens isolate was particularly efficient in colonizing the mosquitoes’ gut, compromising mosquito survival, and inhibiting both sexual- and asexual-stage Plasmodium through secreted factors, thereby rendering it a potential candidate for the development of a malaria transmission intervention strategy. PMID:24428613

  8. Malaria parasites (Plasmodium spp.) infecting introduced, native and endemic New Zealand birds.

    PubMed

    Howe, Laryssa; Castro, Isabel C; Schoener, Ellen R; Hunter, Stuart; Barraclough, Rosemary K; Alley, Maurice R

    2012-02-01

    Avian malaria is caused by intracellular mosquito-transmitted protist parasites in the order Haemosporida, genus Plasmodium. Although Plasmodium species have been diagnosed as causing death in several threatened species in New Zealand, little is known about their ecology and epidemiology. In this study, we examined the presence, microscopic characterization and sequence homology of Plasmodium spp. isolates collected from a small number of New Zealand introduced, native and endemic bird species. We identified 14 Plasmodium spp. isolates from 90 blood or tissue samples. The host range included four species of passerines (two endemic, one native, one introduced), one species of endemic pigeon and two species of endemic kiwi. The isolates were associated into at least four distinct clusters including Plasmodium (Huffia) elongatum, a subgroup of Plasmodium elongatum, Plasmodium relictum and Plasmodium (Noyvella) spp. The infected birds presented a low level of peripheral parasitemia consistent with chronic infection (11/15 blood smears examined). In addition, we report death due to overwhelming parasitemia in a blackbird, a great spotted kiwi and a hihi. These deaths were attributed to infections with either Plasmodium spp. lineage LINN1 or P. relictum lineage GRW4. To the authors' knowledge, this is the first published report of Plasmodium spp. infection in great spotted and brown kiwi, kereru and kokako. Currently, we are only able to speculate on the origin of these 14 isolates but consideration must be made as to the impact they may have on threatened endemic species, particularly due to the examples of mortality.

  9. Plasmodium knowlesi in humans, macaques and mosquitoes in peninsular Malaysia

    PubMed Central

    Vythilingam, Indra; NoorAzian, Yusuf M; Huat, Tan Cheong; Jiram, Adela Ida; Yusri, Yusof M; Azahari, Abdul H; NorParina, Ismail; NoorRain, Abdullah; LokmanHakim, Sulaiman

    2008-01-01

    Background Since a large focus of human infection with Plasmodium knowlesi, a simian malaria parasite naturally found in long-tailed and pig tailed macaques, was reported in Sarawak, Malaysian Borneo, it was pertinent to study the situation in peninsular Malaysia. A study was thus initiated to screen human cases of Plasmodium malariae using molecular techniques, to determine the presence of P. knowlesi in non- human primates and to elucidate its vectors. Methods Nested polymerase chain reaction (PCR) was used to identify all Plasmodium species present in the human blood samples sent to the Parasitology laboratory of Institute for Medical Research. At the same time, non-human primates were also screened for malaria parasites and nested PCR was carried out to determine the presence of P. knowlesi. Mosquitoes were collected from Pahang by human landing collection and monkey-baited-traps situated on three different levels. All mosquitoes were identified and salivary glands and midguts of anopheline mosquitoes were dissected to determine the presence of malaria parasites and nested PCR was carried out on positive glands. Sequencing of the csp genes were carried on P. knowlesi samples from humans, monkeys and mosquitoes, positive by PCR. Results and Discussion Plasmodium knowlesi was detected in 77 (69.37%) of the 111 human samples, 10 (6.90%) of the 145 monkey blood and in 2 (1.7%) Anopheles cracens. Sequence of the csp gene clustered with other P. knowlesi isolates. Conclusion Human infection with Plasmodium knowlesi is occurring in most states of peninsular Malaysia. An. cracens is the main vector. Economic exploitation of the forest is perhaps bringing monkeys, mosquitoes and humans into increased contact. A single bite from a mosquito infected with P. knowlesi is sufficient to introduce the parasite to humans. Thus, this zoonotic transmission has to be considered in the future planning of malaria control. PMID:18710577

  10. Small Molecule Screen for Candidate Antimalarials Targeting Plasmodium Kinesin-5*

    PubMed Central

    Liu, Liqiong; Richard, Jessica; Kim, Sunyoung; Wojcik, Edward J.

    2014-01-01

    Plasmodium falciparum and vivax are responsible for the majority of malaria infections worldwide, resulting in over a million deaths annually. Malaria parasites now show measured resistance to all currently utilized drugs. Novel antimalarial drugs are urgently needed. The Plasmodium Kinesin-5 mechanoenzyme is a suitable “next generation” target. Discovered via small molecule screen experiments, the human Kinesin-5 has multiple allosteric sites that are “druggable.” One site in particular, unique in its sequence divergence across all homologs in the superfamily and even within the same family, exhibits exquisite drug specificity. We propose that Plasmodium Kinesin-5 shares this allosteric site and likewise can be targeted to uncover inhibitors with high specificity. To test this idea, we performed a screen for inhibitors selective for Plasmodium Kinesin-5 ATPase activity in parallel with human Kinesin-5. Our screen of nearly 2000 compounds successfully identified compounds that selectively inhibit both P. vivax and falciparum Kinesin-5 motor domains but, as anticipated, do not impact human Kinesin-5 activity. Of note is a candidate drug that did not biochemically compete with the ATP substrate for the conserved active site or disrupt the microtubule-binding site. Together, our experiments identified MMV666693 as a selective allosteric inhibitor of Plasmodium Kinesin-5; this is the first identified protein target for the Medicines of Malaria Venture validated collection of parasite proliferation inhibitors. This work demonstrates that chemical screens against human kinesins are adaptable to homologs in disease organisms and, as such, extendable to strategies to combat infectious disease. PMID:24737313

  11. Structure, Function and Inhibition of the Phosphoethanolamine Methyltransferases of the Human Malaria Parasites Plasmodium vivax and Plasmodium knowlesi

    PubMed Central

    Garg, Aprajita; Lukk, Tiit; Kumar, Vidya; Choi, Jae-Yeon; Augagneur, Yoann; Voelker, Dennis R.; Nair, Satish; Mamoun, Choukri Ben

    2015-01-01

    Phosphoethanolamine methyltransferases (PMTs) catalyze the three-step methylation of phosphoethanolamine to form phosphocholine, a critical step in the synthesis of phosphatidylcholine in a select number of eukaryotes including human malaria parasites, nematodes and plants. Genetic studies in the malaria parasite Plasmodium falciparum have shown that the methyltransferase PfPMT plays a critical function in parasite development and differentiation. The presence of PMT orthologs in other malaria parasites that infect humans and their absence in mammals make them ideal targets for the development of selective antimalarials with broad specificity against different Plasmodium species. Here we describe the X-ray structures and biochemical properties of PMT orthologs from Plasmodium vivax and Plasmodium knowlesi and show that both enzymes are inhibited by amodiaquine and NSC158011, two drugs with potent antimalarial activity. Metabolic studies in a yeast mutant that relies on PkPMT or PvPMT for survival demonstrated that these compounds inhibit phosphatidylcholine biosynthesis from ethanolamine. Our structural and functional data provide insights into the mechanism of catalysis and inhibition of PMT enzymes and set the stage for a better design of more specific and selective antimalarial drugs. PMID:25761669

  12. Plasmodium-Specific Molecular Assays Produce Uninterpretable Results and Non-Plasmodium spp. Sequences in Field-Collected Anopheles Vectors

    PubMed Central

    Harrison, Genelle F.; Foley, Desmond H.; Rueda, Leopoldo M.; Melanson, Vanessa R.; Wilkerson, Richard C.; Long, Lewis S.; Richardson, Jason H.; Klein, Terry A.; Kim, Heung-Chul; Lee, Won-Ja

    2013-01-01

    The Malaria Research and Reference Reagent Resource–recommended PLF/UNR/VIR polymerase chain reaction (PCR) was used to detect Plasmodium vivax in Anopheles spp. mosquitoes collected in South Korea. Samples that were amplified were sequenced and compared with known Plasmodium spp. by using the PlasmoDB.org Basic Local Alignment Search Tool/n and the National Center for Biotechnology Information Basic Local Alignment Search Tool/n tools. Results show that the primers PLF/UNR/VIR used in this PCR can produce uninterpretable results and non-specific sequences in field-collected mosquitoes. Three additional PCRs (PLU/VIV, specific for 18S small subunit ribosomal DNA; Pvr47, specific for a nuclear repeat; and GDCW/PLAS, specific for the mitochondrial marker, cytB) were then used to find a more accurate and interpretable assay. Samples that were amplified were again sequenced. The PLU/VIV and Pvr47 assays showed cross-reactivity with non-Plasmodium spp. and an arthropod fungus (Zoophthora lanceolata). The GDCW/PLAS assay amplified only Plasmodium spp. but also amplified the non-human specific parasite P. berghei from an Anopheles belenrae mosquito. Detection of P. berghei in South Korea is a new finding. PMID:24189365

  13. Changing trends in prevalence of different Plasmodium species with dominance of Plasmodium falciparum malaria infection in Aligarh (India).

    PubMed

    Khan, Haris M; Shujatullah, Fatima; Ashfaq, Mohammad; Raza, Adil

    2011-01-01

    To determine the prevalence of malaria in Aligarh and analyze species dominance in different years over a decade. Diagnosis of malaria was done using microscopy as gold standard, rapid antigen detection assays and quantitative buffy coat (QBC) assays. Giemsa stained blood smear examination was done, thick and thin films were examined for presence of different Plasmodium spp. Rapid antigen detection assays employing detection of HRP-2 and parasite lactate dehydrogenase antigen (pLDH) by immunochromatography was done in patients whose blood smear found to be negative by conventional Giemsa slide examination. QBC was done in cases where there is strong clinical suspicion of malaria with blood smear negative, in patients with chronic malaria, splenomegaly, or in those patients who had inadequate treatment and for post-treatment follow up. Plasmodium vivax and Plasmodium falciparum were only species detected in our hospital. Overall prevalence of malaria in Aligarh was found to be 8.8%. The maximum prevalence of 20.1% was observed in year 2008 and lowest 2.3% in 2002. High prevalence of malaria is observed in this part of country with dominance of both species particularly Plasmodium falciparum should be monitored and factors accounting for occurrence should be studied to employ effective control measures. Copyright © 2011 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

  14. Characterizing Antibody Responses to Plasmodium vivax and Plasmodium falciparum Antigens in India Using Genome-Scale Protein Microarrays

    PubMed Central

    Awasthi, Vikky; Verma, Kalpana; Sutton, Patrick; Ali, Syed Zeeshan; Patel, Ankita; G., Sri Lakshmi Priya; Ravishankaran, Sangamithra; Desai, Nisha; Tandel, Nikunj; Choubey, Sandhya; Barla, Punam; Kanagaraj, Deena; Eapen, Alex; Pradhan, Khageswar; Singh, Ranvir; Jain, Aarti; Felgner, Philip L.; Davies, D. Huw; Das, Jyoti

    2017-01-01

    Understanding naturally acquired immune responses to Plasmodium in India is key to improving malaria surveillance and diagnostic tools. Here we describe serological profiling of immune responses at three sites in India by probing protein microarrays consisting of 515 Plasmodium vivax and 500 Plasmodium falciparum proteins with 353 plasma samples. A total of 236 malaria-positive (symptomatic and asymptomatic) plasma samples and 117 malaria-negative samples were collected at three field sites in Raurkela, Nadiad, and Chennai. Indian samples showed significant seroreactivity to 265 P. vivax and 373 P. falciparum antigens, but overall seroreactivity to P. vivax antigens was lower compared to P. falciparum antigens. We identified the most immunogenic antigens of both Plasmodium species that were recognized at all three sites in India, as well as P. falciparum antigens that were associated with asymptomatic malaria. This is the first genome-scale analysis of serological responses to the two major species of malaria parasite in India. The range of immune responses characterized in different endemic settings argues for targeted surveillance approaches tailored to the diverse epidemiology of malaria across the world. PMID:28118367

  15. Characterizing Antibody Responses to Plasmodium vivax and Plasmodium falciparum Antigens in India Using Genome-Scale Protein Microarrays.

    PubMed

    Uplekar, Swapna; Rao, Pavitra Nagesh; Ramanathapuram, Lalitha; Awasthi, Vikky; Verma, Kalpana; Sutton, Patrick; Ali, Syed Zeeshan; Patel, Ankita; G, Sri Lakshmi Priya; Ravishankaran, Sangamithra; Desai, Nisha; Tandel, Nikunj; Choubey, Sandhya; Barla, Punam; Kanagaraj, Deena; Eapen, Alex; Pradhan, Khageswar; Singh, Ranvir; Jain, Aarti; Felgner, Philip L; Davies, D Huw; Carlton, Jane M; Das, Jyoti

    2017-01-01

    Understanding naturally acquired immune responses to Plasmodium in India is key to improving malaria surveillance and diagnostic tools. Here we describe serological profiling of immune responses at three sites in India by probing protein microarrays consisting of 515 Plasmodium vivax and 500 Plasmodium falciparum proteins with 353 plasma samples. A total of 236 malaria-positive (symptomatic and asymptomatic) plasma samples and 117 malaria-negative samples were collected at three field sites in Raurkela, Nadiad, and Chennai. Indian samples showed significant seroreactivity to 265 P. vivax and 373 P. falciparum antigens, but overall seroreactivity to P. vivax antigens was lower compared to P. falciparum antigens. We identified the most immunogenic antigens of both Plasmodium species that were recognized at all three sites in India, as well as P. falciparum antigens that were associated with asymptomatic malaria. This is the first genome-scale analysis of serological responses to the two major species of malaria parasite in India. The range of immune responses characterized in different endemic settings argues for targeted surveillance approaches tailored to the diverse epidemiology of malaria across the world.

  16. Structure, Function and Inhibition of the Phosphoethanolamine Methyltransferases of the Human Malaria Parasites Plasmodium vivax and Plasmodium knowlesi

    DOE PAGES

    Garg, Aprajita; Lukk, Tiit; Kumar, Vidya; ...

    2015-03-12

    Phosphoethanolamine methyltransferases (PMTs) catalyze the three-step methylation of phosphoethanolamine to form phosphocholine, a critical step in the synthesis of phosphatidylcholine in a select number of eukaryotes including human malaria parasites, nematodes and plants. Genetic studies in the malaria parasite Plasmodium falciparum have shown that the methyltransferase PfPMT plays a critical function in parasite development and differentiation. The presence of PMT orthologs in other malaria parasites that infect humans and their absence in mammals make them ideal targets for the development of selective antimalarials with broad specificity against different Plasmodium species. Here we describe the X-ray structures and biochemical properties ofmore » PMT orthologs from Plasmodium vivax and Plasmodium knowlesi and show that both enzymes are inhibited by amodiaquine and NSC158011, two drugs with potent antimalarial activity. Metabolic studies in a yeast mutant that relies on PkPMT or PvPMT for survival demonstrated that these compounds inhibit phosphatidylcholine biosynthesis from ethanolamine. Our structural and functional data provide insights into the mechanism of catalysis and inhibition of PMT enzymes and set the stage for a better design of more specific and selective antimalarial drugs.« less

  17. Structure, Function and Inhibition of the Phosphoethanolamine Methyltransferases of the Human Malaria Parasites Plasmodium vivax and Plasmodium knowlesi

    SciTech Connect

    Garg, Aprajita; Lukk, Tiit; Kumar, Vidya; Choi, Jae-Yeon; Augagneur, Yoann; Voelker, Dennis R.; Nair, Satish; Mamoun, Choukri Ben

    2015-03-12

    Phosphoethanolamine methyltransferases (PMTs) catalyze the three-step methylation of phosphoethanolamine to form phosphocholine, a critical step in the synthesis of phosphatidylcholine in a select number of eukaryotes including human malaria parasites, nematodes and plants. Genetic studies in the malaria parasite Plasmodium falciparum have shown that the methyltransferase PfPMT plays a critical function in parasite development and differentiation. The presence of PMT orthologs in other malaria parasites that infect humans and their absence in mammals make them ideal targets for the development of selective antimalarials with broad specificity against different Plasmodium species. Here we describe the X-ray structures and biochemical properties of PMT orthologs from Plasmodium vivax and Plasmodium knowlesi and show that both enzymes are inhibited by amodiaquine and NSC158011, two drugs with potent antimalarial activity. Metabolic studies in a yeast mutant that relies on PkPMT or PvPMT for survival demonstrated that these compounds inhibit phosphatidylcholine biosynthesis from ethanolamine. Our structural and functional data provide insights into the mechanism of catalysis and inhibition of PMT enzymes and set the stage for a better design of more specific and selective antimalarial drugs.

  18. Plasmodium-specific molecular assays produce uninterpretable results and non-Plasmodium spp. sequences in field-collected Anopheles vectors.

    PubMed

    Harrison, Genelle F; Foley, Desmond H; Rueda, Leopoldo M; Melanson, Vanessa R; Wilkerson, Richard C; Long, Lewis S; Richardson, Jason H; Klein, Terry A; Kim, Heung-Chul; Lee, Won-Ja

    2013-12-01

    The Malaria Research and Reference Reagent Resource-recommended PLF/UNR/VIR polymerase chain reaction (PCR) was used to detect Plasmodium vivax in Anopheles spp. mosquitoes collected in South Korea. Samples that were amplified were sequenced and compared with known Plasmodium spp. by using the PlasmoDB.org Basic Local Alignment Search Tool/n and the National Center for Biotechnology Information Basic Local Alignment Search Tool/n tools. Results show that the primers PLF/UNR/VIR used in this PCR can produce uninterpretable results and non-specific sequences in field-collected mosquitoes. Three additional PCRs (PLU/VIV, specific for 18S small subunit ribosomal DNA; Pvr47, specific for a nuclear repeat; and GDCW/PLAS, specific for the mitochondrial marker, cytB) were then used to find a more accurate and interpretable assay. Samples that were amplified were again sequenced. The PLU/VIV and Pvr47 assays showed cross-reactivity with non-Plasmodium spp. and an arthropod fungus (Zoophthora lanceolata). The GDCW/PLAS assay amplified only Plasmodium spp. but also amplified the non-human specific parasite P. berghei from an Anopheles belenrae mosquito. Detection of P. berghei in South Korea is a new finding.

  19. Anopheles moucheti and Anopheles vinckei are candidate vectors of ape Plasmodium parasites, including Plasmodium praefalciparum in Gabon.

    PubMed

    Paupy, Christophe; Makanga, Boris; Ollomo, Benjamin; Rahola, Nil; Durand, Patrick; Magnus, Julie; Willaume, Eric; Renaud, François; Fontenille, Didier; Prugnolle, Franck

    2013-01-01

    During the last four years, knowledge about the diversity of Plasmodium species in African great apes has considerably increased. Several new species were described in chimpanzees and gorillas, and some species that were previously considered as strictly of human interest were found to be infecting African apes. The description in gorillas of P. praefalciparum, the closest relative of P. falciparum which is the main malignant agent of human malaria, definitively changed the way we understand the evolution and origin of P. falciparum. This parasite is now considered to have appeared recently, following a cross-species transfer from gorillas to humans. However, the Plasmodium vector mosquito species that have served as bridge between these two host species remain unknown. In order to identify the vectors that ensure ape Plasmodium transmission and evaluate the risk of transfer of these parasites to humans, we carried out a field study in Gabon to capture Anopheles in areas where wild and semi-wild ape populations live. We collected 1070 Anopheles females belonging to 15 species, among which An. carnevalei, An. moucheti and An. marshallii were the most common species. Using mtDNA-based PCR tools, we discovered that An. moucheti, a major human malaria vector in Central Africa, could also ensure the natural transmission of P. praefalciparum among great apes. We also showed that, together with An. vinckei, An. moucheti was infected with P. vivax-like parasites. An. moucheti constitutes, therefore, a major candidate for the transfer of Plasmodium parasites from apes to humans.

  20. Endemicity response timelines for Plasmodium falciparum elimination.

    PubMed

    Smith, David L; Hay, Simon I

    2009-04-30

    The scaling up of malaria control and renewed calls for malaria eradication have raised interest in defining timelines for changes in malaria endemicity. The epidemiological theory for the decline in the Plasmodium falciparum parasite rate (PfPR, the prevalence of infection) following intervention was critically reviewed and where necessary extended to consider superinfection, heterogeneous biting, and aging infections. Timelines for malaria control and elimination under different levels of intervention were then established using a wide range of candidate mathematical models. Analysis focused on the timelines from baseline to 1% and from 1% through the final stages of elimination. The Ross-Macdonald model, which ignores superinfection, was used for planning during the Global Malaria Eradication Programme (GMEP). In models that consider superinfection, PfPR takes two to three years longer to reach 1% starting from a hyperendemic baseline, consistent with one of the few large-scale malaria control trials conducted in an African population with hyperendemic malaria. The time to elimination depends fundamentally upon the extent to which malaria transmission is interrupted and the size of the human population modelled. When the PfPR drops below 1%, almost all models predict similar and proportional declines in PfPR in consecutive years from 1% through to elimination and that the waiting time to reduce PfPR from 10% to 1% and from 1% to 0.1% are approximately equal, but the decay rate can increase over time if infections senesce. The theory described herein provides simple "rules of thumb" and likely time horizons for the impact of interventions for control and elimination. Starting from a hyperendemic baseline, the GMEP planning timelines, which were based on the Ross-Macdonald model with completely interrupted transmission, were inappropriate for setting endemicity timelines and they represent the most optimistic scenario for places with lower endemicity. Basic

  1. Plasmodium Genus Assay Transition to the Joint Biological Agent Identification and Diagnostic System (JBAIDS)

    DTIC Science & Technology

    2012-07-12

    Support of the Joint Biological Agent Identification and Diagnosis System (JBAIDS): Malaria ( Plasmodium /JBAIDS)." Follow-on RDT&E efforts...conducted by Army collaborators exceeded assay development objectives proposed under this study. Plasmodium falciparum and Plasmodium vivax TaqMan...casualties. Over 25% of marines deployed to Liberia in 2003 were infected with the potentially fatal falciparum malaria . Between 2003 and 2005

  2. Genetic loci associated with delayed clearance of Plasmodium falciparum following artemisinin treatment in Southeast Asia

    DTIC Science & Technology

    2013-01-02

    molecular markers Artemisinin-based combination therapies (ACTs) are the lead-ing treatment for Plasmodium falciparum malaria (1), and their use with... Plasmodium falciparum malaria . N Engl J Med 361(5):455–467. 8. Noedl H, et al.; Artemisinin Resistance in Cambodia 1 (ARC1) Study Consortium (2008...Genetic loci associated with delayed clearance of Plasmodium falciparum following artemisinin treatment in Southeast Asia Shannon Takala-Harrisona

  3. Plasmodium berghei-Hamster Cheek Pouch Model for the Study of Severe Malaria

    DTIC Science & Technology

    1988-11-21

    rCFILE COY ] Plasmodium berghei-llansler Cheek Pouch Model for the study of Severe Malaria Lfl C) David R. Franz, Wallace B. Baze, G. David Young...PROGRAM PROJECT TASK WORK UNIT ELEMENT NO. NO. NO. ACCESSION NO. 11. TITLE (Include Security Classification) Plasmodium bergehei-Hamster Cheek Pouch Model...CODES 18. SUBJECT TERMS (Continue on reverse if necesry and identify by block number) FIELD GROUP SUB-GROUP Hamster cheek pouch, Plasmodium berghei

  4. Species-specific escape of Plasmodium sporozoites from oocysts of avian, rodent, and human malarial parasites.

    PubMed

    Orfano, Alessandra S; Nacif-Pimenta, Rafael; Duarte, Ana P M; Villegas, Luis M; Rodrigues, Nilton B; Pinto, Luciana C; Campos, Keillen M M; Pinilla, Yudi T; Chaves, Bárbara; Barbosa Guerra, Maria G V; Monteiro, Wuelton M; Smith, Ryan C; Molina-Cruz, Alvaro; Lacerda, Marcus V G; Secundino, Nágila F C; Jacobs-Lorena, Marcelo; Barillas-Mury, Carolina; Pimenta, Paulo F P

    2016-08-02

    Malaria is transmitted when an infected mosquito delivers Plasmodium sporozoites into a vertebrate host. There are many species of Plasmodium and, in general, the infection is host-specific. For example, Plasmodium gallinaceum is an avian parasite, while Plasmodium berghei infects mice. These two parasites have been extensively used as experimental models of malaria transmission. Plasmodium falciparum and Plasmodium vivax are the most important agents of human malaria, a life-threatening disease of global importance. To complete their life cycle, Plasmodium parasites must traverse the mosquito midgut and form an oocyst that will divide continuously. Mature oocysts release thousands of sporozoites into the mosquito haemolymph that must reach the salivary gland to infect a new vertebrate host. The current understanding of the biology of oocyst formation and sporozoite release is mostly based on experimental infections with P. berghei, and the conclusions are generalized to other Plasmodium species that infect humans without further morphological analyses. Here, it is described the microanatomy of sporozoite escape from oocysts of four Plasmodium species: the two laboratory models, P. gallinaceum and P. berghei, and the two main species that cause malaria in humans, P. vivax and P. falciparum. It was found that sporozoites have species-specific mechanisms of escape from the oocyst. The two model species of Plasmodium had a common mechanism, in which the oocyst wall breaks down before sporozoites emerge. In contrast, P. vivax and P. falciparum sporozoites show a dynamic escape mechanism from the oocyst via polarized propulsion. This study demonstrated that Plasmodium species do not share a common mechanism of sporozoite escape, as previously thought, but show complex and species-specific mechanisms. In addition, the knowledge of this phenomenon in human Plasmodium can facilitate transmission-blocking studies and not those ones only based on the murine and avian models.

  5. Drug and Vaccine Evaluation in the Human Aotus Plasmodium Falciparum Model

    DTIC Science & Technology

    2007-11-02

    AD Award Number: DAMDl7-01-C-0039 TITLE: Drug and Vaccine Evaluation in the Human Aotus Plasmodium Falciparum Model PRINCIPAL INVESTIGATOR: Nicanor... Human Aotus DAMDI7-01-C-0039 Plasmodium Falciparum Model 6. AUTHOR(S): Nicanor Obaldia, III, D.V.M. 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8...evaluation of drugs and vaccines in the human malarialAotus lemurinus lemurinus monkey model experimientally infected with Plasmodium falciparum or vivax

  6. Impact of climate variability on Plasmodium vivax and Plasmodium falciparum malaria in Yunnan Province, China.

    PubMed

    Bi, Yan; Yu, Weiwei; Hu, Wenbiao; Lin, Hualiang; Guo, Yuming; Zhou, Xiao-Nong; Tong, Shilu

    2013-12-17

    Malaria remains a public health problem in the remote and poor area of Yunnan Province, China. Yunnan faces an increasing risk of imported malaria infections from Mekong river neighboring countries. This study aimed to identify the high risk area of malaria transmission in Yunnan Province, and to estimate the effects of climatic variability on the transmission of Plasmodium vivax and Plasmodium falciparum in the identified area. We identified spatial clusters of malaria cases using spatial cluster analysis at a county level in Yunnan Province, 2005-2010, and estimated the weekly effects of climatic factors on P. vivax and P. falciparum based on a dataset of daily malaria cases and climatic variables. A distributed lag nonlinear model was used to estimate the impact of temperature, relative humidity and rainfall up to 10-week lags on both types of malaria parasite after adjusting for seasonal and long-term effects. The primary cluster area was identified along the China-Myanmar border in western Yunnan. A 1°C increase in minimum temperature was associated with a lag 4 to 9 weeks relative risk (RR), with the highest effect at lag 7 weeks for P. vivax (RR = 1.03; 95% CI, 1.01, 1.05) and 6 weeks for P. falciparum (RR = 1.07; 95% CI, 1.04, 1.11); a 10-mm increment in rainfall was associated with RRs of lags 2-4 weeks and 9-10 weeks, with the highest effect at 3 weeks for both P. vivax (RR = 1.03; 95% CI, 1.01, 1.04) and P. falciparum (RR = 1.04; 95% CI, 1.01, 1.06); and the RRs with a 10% rise in relative humidity were significant from lag 3 to 8 weeks with the highest RR of 1.24 (95% CI, 1.10, 1.41) for P. vivax at 5-week lag. Our findings suggest that the China-Myanmar border is a high risk area for malaria transmission. Climatic factors appeared to be among major determinants of malaria transmission in this area. The estimated lag effects for the association between temperature and malaria are consistent with the life cycles of both mosquito vector and malaria

  7. Thrombocytopenia in Plasmodium falciparum, Plasmodium vivax and mixed infection malaria: a study from Bikaner (Northwestern India).

    PubMed

    Kochar, Dhanpat Kumar; Das, Ashis; Kochar, Abhishek; Middha, Sheetal; Acharya, Jyoti; Tanwar, Gajanand Singh; Gupta, Anjana; Pakalapati, Deepak; Garg, Shilpi; Saxena, Vishal; Subudhi, Amit Kumar; Boopathi, P A; Sirohi, Parmendra; Kochar, Sanjay Kumar

    2010-01-01

    The occurrence, relation and magnitude of thrombocytopenia in different species of malaria are not clearly defined. This study included 1,064 patients admitted with malaria to study thrombocytopenia (platelet count <150,000 /cumm) in Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) mono infection and mixed infection (Pf + Pv). The species diagnosis was done by peripheral blood film (PBF) and rapid diagnostic test (RDT). Validation by polymerase chain reaction (PCR) was done only in patients with severe thrombocytopenia (platelet count <20,000 /cumm). The breakup of patients was 525 (49.34%) Pf, 460 (43.23%) Pv and 79 (7.42%) mixed malaria (Pf + Pv). Thrombocytopenia was observed in 24.6% (262/1064) patients. The risk was greatest in the mixed infections in comparison to monoinfection individually (43.04% [34/79]; mixed vs Pv monoinfection: Odds Ratio [OR] = 1.675 [95% Confidence Interval (CI) 1.029-2.726], p < 0.0366; mixed vs Pf monoinfection: OR=3.911 [95% CI 2.367-6.463], p < 0.0001). Pv monoinfection (31.09% [143/460]) had greater risk compared to Pf monoinfection (16.19% [85/525]; OR = 2.335 [95% CI 1.722-3.167], p < 0.0001). The occurrence of severe thrombocytopenia was also higher in Pv monoinfection (18.18% [26/143]) in comparison to either Pf monoinfection (10.59% [9/85], OR = 1.877 (95% CI 0.834-4.223)) or mixed infection (11.76% [4/34]; OR = 1.667 (95% CI 0.540-5.142) but this association was statistically not significant. Six patients (3 Pv, 2 Pf and 1 mixed) developed severe epistaxis requiring platelet transfusion. There was no relation between parasite density and platelet count as many patients with severe thrombocytopenia had parasite density similar to patients without thrombocytopenia. We found that the association of thrombocytopenia was statistically more significant with P. vivax monoinfection as compared to P. falciparum.

  8. Merozoite surface protein-1 genetic diversity in Plasmodium malariae and Plasmodium brasilianum from Brazil.

    PubMed

    Guimarães, Lilian O; Wunderlich, Gerhard; Alves, João M P; Bueno, Marina G; Röhe, Fabio; Catão-Dias, José L; Neves, Amanda; Malafronte, Rosely S; Curado, Izilda; Domingues, Wilson; Kirchgatter, Karin

    2015-11-16

    The merozoite surface protein 1 (MSP1) gene encodes the major surface antigen of invasive forms of the Plasmodium erythrocytic stages and is considered a candidate vaccine antigen against malaria. Due to its polymorphisms, MSP1 is also useful for strain discrimination and consists of a good genetic marker. Sequence diversity in MSP1 has been analyzed in field isolates of three human parasites: P. falciparum, P. vivax, and P. ovale. However, the extent of variation in another human parasite, P. malariae, remains unknown. This parasite shows widespread, uneven distribution in tropical and subtropical regions throughout South America, Asia, and Africa. Interestingly, it is genetically indistinguishable from P. brasilianum, a parasite known to infect New World monkeys in Central and South America. Specific fragments (1 to 5) covering 60 % of the MSP1 gene (mainly the putatively polymorphic regions), were amplified by PCR in isolates of P. malariae and P. brasilianum from different geographic origin and hosts. Sequencing of the PCR-amplified products or cloned PCR fragments was performed and the sequences were used to construct a phylogenetic tree by the maximum likelihood method. Data were computed to give insights into the evolutionary and phylogenetic relationships of these parasites. Except for fragment 4, sequences from all other fragments consisted of unpublished sequences. The most polymorphic gene region was fragment 2, and in samples where this region lacks polymorphism, all other regions are also identical. The low variability of the P. malariae msp1 sequences of these isolates and the identification of the same haplotype in those collected many years apart at different locations is compatible with a low transmission rate. We also found greater diversity among P. brasilianum isolates compared with P. malariae ones. Lastly, the sequences were segregated according to their geographic origins and hosts, showing a strong genetic and geographic structure. Our data

  9. Plasmodium knowlesi: from Malaysia, a novel health care threat.

    PubMed

    Sabbatani, Sergio; Fiorino, Sirio; Manfredi, Roberto

    2012-03-01

    Epidemic foci of Plasmodium knowlesi malaria have been identified during the past ten years in Malaysia, in particular in the States of Sarawak and Sabah (Malaysia Borneo), and in the Pahang region (peninsular Malaysia). Based on a review of the available recent international literature, the authors underline the importance of molecular biology examinations, polymerase chain reactions (PCR), performed with primers specific for P. knowlesi, since the current microscopic examination (haemoscope) may fail to distinguish P. knowlesi from Plasmodium malariae, due to the very similar appearance of the two parasites. P. knowlesi has been described as the causal agent of life-threatening and lethal forms of malaria: its clinical picture is more severe when compared with that of P. malariae, since the disease is characterized by greater parasitaemia, as opposed to that documented in the course of P. malariae disease. The most effective carrier is Anopheles leucosphyrus: this mosquito is attracted by both humans and monkeys. Among primates, the natural hosts of P. knowlesi are Macaca fascicularis and Macaca nemestina, while Saimiri scirea and Macaca mulatta, which cannot become infected in nature, may be useful in experimental models. When underlining the potentially severe evolution, we note the key role played by prompt disease recognition, which is expected to be more straightforward in patients monitored in endemic countries at high risk, but should be carefully implemented for subjects being admitted to hospital in Western countries suffering from the typical signs and symptoms of malaria, after travelling in South-East Asia where they were engaged in excursions in the tropical forest (trekking, and similar outdoor activities). In these cases, the diagnosis should be prompt, and suitable treatment should follow. According to data in the literature, in non-severe cases chloroquine proves very effective against P. knowlesi, achieving the disappearance of signs and

  10. Plasmodium spp. in raptors on the Eurasian-African migration route.

    PubMed

    Paperna, I; Yosef, R; Landau, I

    2007-12-01

    Examination of blood smears obtained from raptors trapped while on migration at Eilat, Israel, demonstrated Plasmodium infection in Accipiter brevipes and Buteo buteo. The following species are described, from A. brevipes: Plasmodium alloelongatum n. sp., P. accipiteris n. sp. and from B. buteo: P. buteonis n. sp. and Plasmodium sp. for which we lack sufficient data for adequate species description. Overall prevalence of infection with Plasmodium spp. was very low: among 38 examined A. brevipes 5% and among 56 B. buteo 3.6%.

  11. Plasmodium cynomolgi genome sequences provide insight into Plasmodium vivax and the monkey malaria clade.

    PubMed

    Tachibana, Shin-Ichiro; Sullivan, Steven A; Kawai, Satoru; Nakamura, Shota; Kim, Hyunjae R; Goto, Naohisa; Arisue, Nobuko; Palacpac, Nirianne M Q; Honma, Hajime; Yagi, Masanori; Tougan, Takahiro; Katakai, Yuko; Kaneko, Osamu; Mita, Toshihiro; Kita, Kiyoshi; Yasutomi, Yasuhiro; Sutton, Patrick L; Shakhbatyan, Rimma; Horii, Toshihiro; Yasunaga, Teruo; Barnwell, John W; Escalante, Ananias A; Carlton, Jane M; Tanabe, Kazuyuki

    2012-09-01

    P. cynomolgi, a malaria-causing parasite of Asian Old World monkeys, is the sister taxon of P. vivax, the most prevalent malaria-causing species in humans outside of Africa. Because P. cynomolgi shares many phenotypic, biological and genetic characteristics with P. vivax, we generated draft genome sequences for three P. cynomolgi strains and performed genomic analysis comparing them with the P. vivax genome, as well as with the genome of a third previously sequenced simian parasite, Plasmodium knowlesi. Here, we show that genomes of the monkey malaria clade can be characterized by copy-number variants (CNVs) in multigene families involved in evasion of the human immune system and invasion of host erythrocytes. We identify genome-wide SNPs, microsatellites and CNVs in the P. cynomolgi genome, providing a map of genetic variation that can be used to map parasite traits and study parasite populations. The sequencing of the P. cynomolgi genome is a critical step in developing a model system for P. vivax research and in counteracting the neglect of P. vivax.

  12. In vivo resistance to chloroquine by Plasmodium vivax and Plasmodium falciparum at Nabire, Irian Jaya, Indonesia.

    PubMed

    Baird, J K; Wiady, I; Fryauff, D J; Sutanihardja, M A; Leksana, B; Widjaya, H; Kysdarmanto; Subianto, B

    1997-06-01

    A survey of resistance to chloroquine by Plasmodium vivax and P. falciparum was conducted during May 1995 at three mesoendemic villages 30 km southeast of Nabire, near the central northern coast of Irian Jaya, Indonesia. The prevalence of malaria at Urusumu (n = 157), Margajaya (n = 573), and Topo (n = 199) was 18%. 9%, and 9%, respectively, with spleen rates among children of 79%, 10%, and 27%. Infected patients among those screened formed a study population of 64 subjects eligible for a 28-day in vivo test of resistance to chloroquine. Sixty-three patients successfully completed the test; 45 males and 18 females 1-60 years of age, of whom 29 were Javanese transmigrants of five years residence in Irian Jaya and 34 were native to Irian Jaya. The seven-day day cumulative incidence of therapeutic failure for P. vivax and P. falciparum was 15% (n = 34) and 30% (n = 37). The 14- and 28-day estimates of cumulative incidence were 45% and 64% for P. vivax and 58% and 89% for P. falciparum. Almost all recurrences appeared in the face of ordinarily effective levels of chloroquine and its major metabolite, desethylchloroquine, in whole blood (> or = 100 ng/ml). Four infections by P. malariae in subjects enrolled in this study cleared by day 2 and none reappeared within 28 days. Chloroquine no longer provides effective therapy for falciparum or vivax malaria along the northern coast of Irian Jaya, Indonesia.

  13. MOLECULAR SURVEILLANCE OF Plasmodium vivax AND Plasmodium falciparum DHFR MUTATIONS IN ISOLATES FROM SOUTHERN IRAN

    PubMed Central

    SHARIFI-SARASIABI, Khojasteh; HAGHIGHI, Ali; KAZEMI, Bahram; TAGHIPOUR, Niloofar; MOJARAD, Ehsan Nazemalhosseini; GACHKAR, Latif

    2016-01-01

    In Iran, both Plasmodium vivax and P. falciparum malaria have been detected, but P. vivax is the predominant species. Point mutations in dihydrofolate reductase (dhfr) gene in both Plasmodia are the major mechanisms of pyrimethamine resistance. From April 2007 to June 2009, a total of 134 blood samples in two endemic areas of southern Iran were collected from patients infected with P. vivax and P. falciparum. The isolates were analyzed for P. vivax dihydrofolate reductase (pvdhfr) and P. falciparum dihydrofolate reductase (pfdhfr) point mutations using various PCR-based methods. The majority of the isolates (72.9%) had wild type amino acids at five codons of pvdhfr. Amongst mutant isolates, the most common pvdhfr alleles were double mutant in 58 and 117 amino acids (58R-117N). Triple mutation in 57, 58, and 117 amino acids (57L/58R/117N) was identified for the first time in the pvdhfr gene of Iranian P. vivax isolates. All the P. falciparumsamples analyzed (n = 16) possessed a double mutant pfdhfrallele (59R/108N) and retained a wild-type mutation at position 51. This may be attributed to the fact that the falciparum malaria patients were treated using sulfadoxine-pyrimethamine (SP) in Iran. The presence of mutant haplotypes in P. vivax is worrying, but has not yet reached an alarming threshold regarding drugs such as SP. The results of this study reinforce the importance of performing a molecular surveillance by means of a continuous chemoresistance assessment. PMID:27007559

  14. Deaths due to Plasmodium knowlesi malaria in Sabah, Malaysia: association with reporting as Plasmodium malariae and delayed parenteral artesunate.

    PubMed

    Rajahram, Giri S; Barber, Bridget E; William, Timothy; Menon, Jayaram; Anstey, Nicholas M; Yeo, Tsin W

    2012-08-20

    The simian parasite Plasmodium knowlesi is recognized as a common cause of severe and fatal human malaria in Sabah, Malaysia, but is morphologically indistinguishable from and still commonly reported as Plasmodium malariae, despite the paucity of this species in Sabah. Since December 2008 Sabah Department of Health has recommended intravenous artesunate and referral to a general hospital for all severe malaria cases of any species. This paper reviews all malaria deaths in Sabah subsequent to the introduction of these measures. Reporting of malaria deaths in Malaysia is mandatory. Details of reported malaria deaths during 2010-2011 were reviewed to determine the proportion of each Plasmodium species. Demographics, clinical presentations and management of severe malaria caused by each species were compared. Fourteen malaria deaths were reported, comprising seven Plasmodium falciparum, six P. knowlesi and one Plasmodium vivax (all PCR-confirmed). Of the six P. knowlesi deaths, five were attributable to knowlesi malaria and one was attributable to P. knowlesi-associated enterobacter sepsis. Patients with directly attributable P. knowlesi deaths (N = 5) were older than those with P. falciparum (median age 51 [IQR 50-65] vs 22 [IQR 9-55] years, p = 0.06). Complications in fatal P. knowlesi included respiratory distress (N = 5, 100%), hypotension (N = 4, 80%), and renal failure (N = 4, 80%). All patients with P. knowlesi were reported as P. malariae by microscopy. Only two of five patients with severe knowlesi malaria on presentation received immediate parenteral anti-malarial treatment. The patient with P. vivax-associated severe illness did not receive parenteral treatment. In contrast six of seven patients with severe falciparum malaria received immediate parenteral treatment. Plasmodium knowlesi was responsible, either directly or through gram-negative bacteraemia, for almost half of malaria deaths in Sabah. Patients with severe non

  15. Deaths due to Plasmodium knowlesi malaria in Sabah, Malaysia: association with reporting as Plasmodium malariae and delayed parenteral artesunate

    PubMed Central

    2012-01-01

    Background The simian parasite Plasmodium knowlesi is recognized as a common cause of severe and fatal human malaria in Sabah, Malaysia, but is morphologically indistinguishable from and still commonly reported as Plasmodium malariae, despite the paucity of this species in Sabah. Since December 2008 Sabah Department of Health has recommended intravenous artesunate and referral to a general hospital for all severe malaria cases of any species. This paper reviews all malaria deaths in Sabah subsequent to the introduction of these measures. Reporting of malaria deaths in Malaysia is mandatory. Methods Details of reported malaria deaths during 2010-2011 were reviewed to determine the proportion of each Plasmodium species. Demographics, clinical presentations and management of severe malaria caused by each species were compared. Results Fourteen malaria deaths were reported, comprising seven Plasmodium falciparum, six P. knowlesi and one Plasmodium vivax (all PCR-confirmed). Of the six P. knowlesi deaths, five were attributable to knowlesi malaria and one was attributable to P. knowlesi-associated enterobacter sepsis. Patients with directly attributable P. knowlesi deaths (N = 5) were older than those with P. falciparum (median age 51 [IQR 50-65] vs 22 [IQR 9-55] years, p = 0.06). Complications in fatal P. knowlesi included respiratory distress (N = 5, 100%), hypotension (N = 4, 80%), and renal failure (N = 4, 80%). All patients with P. knowlesi were reported as P. malariae by microscopy. Only two of five patients with severe knowlesi malaria on presentation received immediate parenteral anti-malarial treatment. The patient with P. vivax-associated severe illness did not receive parenteral treatment. In contrast six of seven patients with severe falciparum malaria received immediate parenteral treatment. Conclusion Plasmodium knowlesi was responsible, either directly or through gram-negative bacteraemia, for almost half of malaria deaths in Sabah

  16. Imaging Plasmodium Immunobiology in Liver, Brain, and Lung

    PubMed Central

    Frevert, Ute; Nacer, Adéla; Cabrera, Mynthia; Movila, Alexandru; Leberl, Maike

    2013-01-01

    Plasmodium falciparum malaria is responsible for the deaths of over half a million African children annually. Until a decade ago, dynamic analysis of the malaria parasite was limited to in vitro systems with the typical limitations associated with 2D monocultures or entirely artificial surfaces. Due to extremely low parasite densities, the liver was considered a black box in terms of Plasmodium sporozoite invasion, liver stage development, and merozoite release into the blood. Further, nothing was known about the behavior of blood stage parasites in organs such as brain where clinical signs manifest and the ensuing immune response of the host that may ultimately result in a fatal outcome. The advent of fluorescent parasites, advances in imaging technology, and availability of an ever-increasing number of cellular and molecular probes have helped illuminate many steps along the pathogenetic cascade of this deadly tropical parasite. PMID:24076429

  17. Mosquito Vectors and the Globalization of Plasmodium falciparum Malaria.

    PubMed

    Molina-Cruz, Alvaro; Zilversmit, Martine M; Neafsey, Daniel E; Hartl, Daniel L; Barillas-Mury, Carolina

    2016-11-23

    Plasmodium falciparum malaria remains a devastating public health problem. Recent discoveries have shed light on the origin and evolution of Plasmodium parasites and their interactions with their vertebrate and mosquito hosts. P. falciparum malaria originated in Africa from a single horizontal transfer between an infected gorilla and a human, and became global as the result of human migration. Today, P. falciparum malaria is transmitted worldwide by more than 70 different anopheline mosquito species. Recent studies indicate that the mosquito immune system can be a barrier to malaria transmission and that the P. falciparum Pfs47 gene allows the parasite to evade mosquito immune detection. Here, we review the origin and globalization of P. falciparum and integrate this history with analysis of the biology, evolution, and dispersal of the main mosquito vectors. This new perspective broadens our understanding of P. falciparum population structure and the dispersal of important parasite genetic traits.

  18. Erythrocyte invasion: vocabulary and grammar of the Plasmodium rhoptry.

    PubMed

    Kaneko, Osamu

    2007-12-01

    Malaria is a dangerous infectious disease caused by obligate intracellular protozoan Plasmodium parasites. In the vertebrate host, erythrocyte recognition and establishment of a nascent parasitophorous vacuole are essential processes, and are largely achieved using molecules located in the microorganelles of the invasive-stage parasites. Recent proteome analyses of the phylogenetically related Toxoplasma parasite have provided protein catalogs for these microorganelles, which can now be used to identify orthologous proteins in the Plasmodium genome. Of importance is the formation of a complex between the proteins secreted from the rhoptry neck portion (RONs) and micronemes (AMA1), which localize at the moving junction during parasite invagination into the host cell. In this article I review the largely unexplored paradigm of the malaria merozoite rhoptry, focusing on the high molecular weight rhoptry protein complex (the RhopH complex), and speculate on its grammar during invasion.

  19. Plasmodium vivax vaccine research - we've only just begun.

    PubMed

    Tham, Wai-Hong; Beeson, James G; Rayner, Julian C

    2017-02-01

    Plasmodium vivax parasites cause the majority of malaria cases outside Africa, and are increasingly being acknowledged as a cause of severe disease. The unique attributes of P. vivax biology, particularly the capacity of the dormant liver stage, the hypnozoite, to maintain blood-stage infections even in the absence of active transmission, make blood-stage vaccines particularly attractive for this species. However, P. vivax vaccine development remains resolutely in first gear, with only a single blood-stage candidate having been evaluated in any depth. Experience with Plasmodium falciparum suggests that a much broader search for new candidates and a deeper understanding of high priority targets will be required to make significant advances. This review discusses some of the particular challenges of P. vivax blood-stage vaccine development, highlighting both recent advances and key remaining barriers to overcome in order to move development forward.

  20. Plasmodium vivax Landscape in Brazil: Scenario and Challenges.

    PubMed

    Siqueira, Andre M; Mesones-Lapouble, Oscar; Marchesini, Paola; Sampaio, Vanderson de Souza; Brasil, Patricia; Tauil, Pedro L; Fontes, Cor Jesus; Costa, Fabio T M; Daniel-Ribeiro, Cláudio Tadeu; Lacerda, Marcus V G; Damasceno, Camila P; Santelli, Ana Carolina S

    2016-12-28

    Brazil is the largest country of Latin America, with a considerable portion of its territoritory within the malaria-endemic Amazon region in the North. Furthermore, a considerable portion of its territory is located within the Amazon region in the north. As a result, Brazil has reported half of the total malaria cases in the Americas in the last four decades. Recent progress in malaria control has been accompanied by an increasing proportion of Plasmodium vivax, underscoring a need for a better understanding of management and control of this species and associated challenges. Among these challenges, the contribution of vivax malaria relapses, earlier production of gametocytes (compared with Plasmodium falciparum), inexistent methods to diagnose hypnozoite carriers, and decreasing efficacy of available antimalarials need to be addressed. Innovative tools, strategies, and technologies are needed to achieve further progress toward sustainable malaria elimination. Further difficulties also arise from dealing with the inherent socioeconomic and environmental particularities of the Amazon region and its dynamic changes.

  1. Antifolate Agents Against Wild and Mutant Strains of Plasmodium falciparum

    PubMed Central

    Shaikh, M. S.; Rana, J.; Gaikwad, D.; Leartsakulpanich, U.; Ambre, Premlata K.; Pissurlenkar, R. R. S.; Coutinho, E. C.

    2014-01-01

    Plasmodium falciparum dihydrofolate reductase is an important target for antimalarial chemotherapy. The emergence of resistance has significantly reduced the efficacy of the classic antifolate drugs cycloguanil and pyrimethamine. In this paper we report new dihydrofolate reductase inhibitors identified using molecular modelling principles with the goal of designing new antifolate agents active against both wild and tetramutant dihydrofolate reductase strains three series of trimethoprim analogues were designed, synthesised and tested for biological activity. Pyrimethamine and cycloguanil have been reported to loose efficacy because of steric repulsion in the active site pocket produced due to mutation in Plasmodium falciparum dihydrofolate reductase. The synthesised molecules have sufficient flexibility to withstand this steric repulsion to counteract the resistance. The molecules have been synthesised by conventional techniques and fully characterised by spectroscopic methods. The potency of these molecules was evaluated by in vitro enzyme specific assays. Some of the molecules were active in micromolar concentrations and can easily be optimised to improve binding and activity. PMID:24843184

  2. Meetings on Plasmodium vivax and Schistosoma japonicum in Asia.

    PubMed

    1999-10-01

    Manila hosted two meetings on malaria and schistosomiasis for Asian scientists in June 1999. Efforts in developing a vaccine for Plasmodium vivax, precursor of 40-50% of malaria in Latin America and Asia, were emphasized: 1) the need for greater understanding of the epidemiology of the vivax malaria, development of immunity, and interactions between the two main species of plasmodium; 2) the role of primate models of vivax malaria; 3) unique biological questions posed by P. vivax; and 4) the large production of existing vivax candidate vaccines for clinical trials. Moreover, the Philippines and China continue to be affected by Schistosoma japonicum despite extensive control efforts and availability of praziquantel. Diversity of opinion over the expected vaccine was discussed. Technical expertise in the production of vaccines has improved while links between researchers and vaccine manufacturers need to be improved.

  3. Predictions of avian Plasmodium expansion under climate change

    PubMed Central

    Loiseau, Claire; Harrigan, Ryan J.; Bichet, Coraline; Julliard, Romain; Garnier, Stéphane; Lendvai, Ádám Z.; Chastel, Olivier; Sorci, Gabriele

    2013-01-01

    Vector-borne diseases are particularly responsive to changing environmental conditions. Diurnal temperature variation has been identified as a particularly important factor for the development of malaria parasites within vectors. Here, we conducted a survey across France, screening populations of the house sparrow (Passer domesticus) for malaria (Plasmodium relictum). We investigated whether variation in remotely-sensed environmental variables accounted for the spatial variation observed in prevalence and parasitemia. While prevalence was highly correlated to diurnal temperature range and other measures of temperature variation, environmental conditions could not predict spatial variation in parasitemia. Based on our empirical data, we mapped malaria distribution under climate change scenarios and predicted that Plasmodium occurrence will spread to regions in northern France, and that prevalence levels are likely to increase in locations where transmission already occurs. Our findings, based on remote sensing tools coupled with empirical data suggest that climatic change will significantly alter transmission of malaria parasites. PMID:23350033

  4. Uncovering the transmission dynamics of Plasmodium vivax using population genetics

    PubMed Central

    Barry, Alyssa E.; Waltmann, Andreea; Koepfli, Cristian; Barnadas, Celine; Mueller, Ivo

    2015-01-01

    Population genetic analysis of malaria parasites has the power to reveal key insights into malaria epidemiology and transmission dynamics with the potential to deliver tools to support control and elimination efforts. Analyses of parasite genetic diversity have suggested that Plasmodium vivax populations are more genetically diverse and less structured than those of Plasmodium falciparum indicating that P. vivax may be a more ancient parasite of humans and/or less susceptible to population bottlenecks, as well as more efficient at disseminating its genes. These population genetic insights into P. vivax transmission dynamics provide an explanation for its relative resilience to control efforts. Here, we describe current knowledge on P. vivax population genetic structure, its relevance to understanding transmission patterns and relapse and how this information can inform malaria control and elimination programmes. PMID:25891915

  5. Driving mosquito refractoriness to Plasmodium falciparum with engineered symbiotic bacteria.

    PubMed

    Wang, Sibao; Dos-Santos, André L A; Huang, Wei; Liu, Kun Connie; Oshaghi, Mohammad Ali; Wei, Ge; Agre, Peter; Jacobs-Lorena, Marcelo

    2017-09-29

    The huge burden of malaria in developing countries urgently demands the development of novel approaches to fight this deadly disease. Although engineered symbiotic bacteria have been shown to render mosquitoes resistant to the parasite, the challenge remains to effectively introduce such bacteria into mosquito populations. We describe a Serratia bacterium strain (AS1) isolated from Anopheles ovaries that stably colonizes the mosquito midgut, female ovaries, and male accessory glands and spreads rapidly throughout mosquito populations. Serratia AS1 was genetically engineered for secretion of anti-Plasmodium effector proteins, and the recombinant strains inhibit development of Plasmodium falciparum in mosquitoes. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  6. Imaging Plasmodium immunobiology in the liver, brain, and lung.

    PubMed

    Frevert, Ute; Nacer, Adéla; Cabrera, Mynthia; Movila, Alexandru; Leberl, Maike

    2014-02-01

    Plasmodium falciparum malaria is responsible for the deaths of over half a million African children annually. Until a decade ago, dynamic analysis of the malaria parasite was limited to in vitro systems with the typical limitations associated with 2D monocultures or entirely artificial surfaces. Due to extremely low parasite densities, the liver was considered a black box in terms of Plasmodium sporozoite invasion, liver stage development, and merozoite release into the blood. Further, nothing was known about the behavior of blood stage parasites in organs such as the brain where clinical signs manifest and the ensuing immune response of the host that may ultimately result in a fatal outcome. The advent of fluorescent parasites, advances in imaging technology, and availability of an ever-increasing number of cellular and molecular probes have helped illuminate many steps along the pathogenetic cascade of this deadly tropical parasite.

  7. Optimal Control Strategy of Plasmodium vivax Malaria Transmission in Korea

    PubMed Central

    Kim, Byul Nim; Nah, Kyeongah; Chu, Chaeshin; Ryu, Sang Uk; Kang, Yong Han; Kim, Yongkuk

    2012-01-01

    Objective To investigate the optimal control strategy for Plasmodium vivax malaria transmission in Korea. Methods A Plasmodium vivax malaria transmission model with optimal control terms using a deterministic system of differential equations is presented, and analyzed mathematically and numerically. Results If the cost of reducing the reproduction rate of the mosquito population is more than that of prevention measures to minimize mosquito-human contacts, the control of mosquito-human contacts needs to be taken for a longer time, comparing the other situations. More knowledge about the actual effectiveness and costs of control intervention measures would give more realistic control strategies. Conclusion Mathematical model and numerical simulations suggest that the use of mosquito-reduction strategies is more effective than personal protection in some cases but not always. PMID:24159504

  8. Drug Evaluation in the Plasmodium Falciparum - Aotus Model

    DTIC Science & Technology

    1994-03-15

    chloroquine, quinine, and pyrimethamine. Am J Trop Med Hyg 27:703-717. 3. Rossan, RN, Harper, JS III, Davidson, DE Jr., Escajadillo , A. and...primaquine. Presented at XII International Congress for Tropical Medicine and Malaria. Amsterdam. 6, Pollack, S, Rossan, RN, Davidson, DE, Escajadillo , A...1987. Desferrioxamine suppresses Plasmodium falciparum in Aotus monkeys. Proc Soc Expt Biol Med. 184-162-164. 7. Panton, LJ, Rossan, RN, Escajadillo

  9. World Malaria Report: time to acknowledge Plasmodium knowlesi malaria.

    PubMed

    Barber, Bridget E; Rajahram, Giri S; Grigg, Matthew J; William, Timothy; Anstey, Nicholas M

    2017-03-31

    The 2016 World Health Organization (WHO) World Malaria Report documents substantial progress towards control and elimination of malaria. However, major challenges remain. In some regions of Southeast Asia, the simian parasite Plasmodium knowlesi has emerged as an important cause of human malaria, and the authors believe this species warrants regular inclusion in the World Malaria Report. Plasmodium knowlesi is the most common cause of malaria in Malaysia, and cases have also been reported in nearly all countries of Southeast Asia. Outside of Malaysia, P. knowlesi is frequently misdiagnosed by microscopy as Plasmodium falciparum or Plasmodium vivax. Thus, P. knowlesi may be underdiagnosed in affected regions and its true incidence underestimated. Acknowledgement in the World Malaria Report of the regional importance of P. knowlesi will facilitate efforts to improve surveillance of this emerging parasite. Furthermore, increased recognition will likely lead to improved delivery of effective treatment for this potentially fatal infection, as has occurred in Malaysia where P. knowlesi case-fatality rates have fallen despite rising incidence. In a number of knowlesi-endemic countries, substantial progress has been made towards the elimination of P. vivax and P. falciparum. However, efforts to eliminate these human-only species should not preclude efforts to reduce human malaria from P. knowlesi. The regional importance of knowlesi malaria was recognized by the WHO with its recent Evidence Review Group meeting on knowlesi malaria to address strategies for prevention and mitigation. The WHO World Malaria Report has an appropriate focus on falciparum and vivax malaria, the major causes of global mortality and morbidity. However, the authors hope that in future years this important publication will also incorporate data on the progress and challenges in reducing knowlesi malaria in regions where transmission occurs.

  10. Subinoculation as a technique in the diagnosis of avian plasmodium

    USGS Publications Warehouse

    Herman, C.M.; Knisley, J.O.; Snyder, E.L.

    1966-01-01

    In two successive years, 1964 and 1965, blood subinoculated from wild Canada geese, negative for Plasmodium by examination of peripheral blood smears, into 5-day-old domestic geese produced 60 % infection in the recipients. Prepatent and patent periods, as well as intensity of parasitemia showed much variation. Intramuscular inoculation produced the same prevalence as the intravenous route, but longer prepatent periods and less intensity of parasitemia.

  11. Plasmodium falciparum genetic crosses in a humanized mouse model

    PubMed Central

    Vaughan, Ashley M.; Pinapati, Richard S.; Cheeseman, Ian H.; Camargo, Nelly; Fishbaugher, Matthew; Checkley, Lisa A.; Nair, Shalini; Hutyra, Carolyn A.; Nosten, François H.; Anderson, Timothy J. C.; Ferdig, Michael T.; Kappe, Stefan H. I.

    2015-01-01

    Genetic crosses of phenotypically distinct strains of the human malaria parasite Plasmodium falciparum are a powerful tool for identifying genes controlling drug resistance and other key phenotypes. Previous studies relied on the isolation of recombinant parasites from splenectomized chimpanzees, a research avenue that is no longer available. Here, we demonstrate that human-liver chimeric mice support recovery of recombinant progeny for the identification of genetic determinants of parasite traits and adaptations. PMID:26030447

  12. Fate of haem iron in the malaria parasite Plasmodium falciparum.

    PubMed Central

    Egan, Timothy J; Combrinck, Jill M; Egan, Joanne; Hearne, Giovanni R; Marques, Helder M; Ntenteni, Skhumbuzo; Sewell, B Trevor; Smith, Peter J; Taylor, Dale; van Schalkwyk, Donelly A; Walden, Jason C

    2002-01-01

    Chemical analysis has shown that Plasmodium falciparum trophozoites contain 61+/-2% of the iron within parasitized erythrocytes, of which 92+/-6% is located within the food vacuole. Of this, 88+/-9% is in the form of haemozoin. (57)Fe-Mössbauer spectroscopy shows that haemozoin is the only detectable iron species in trophozoites. Electron spectroscopic imaging confirms this conclusion. PMID:12033986

  13. Structure of Plasmodium falciparum ADP-ribosylation factor 1

    PubMed Central

    Cook, William J.; Smith, Craig D.; Senkovich, Olga; Holder, Anthony A.; Chattopadhyay, Debasish

    2010-01-01

    Vesicular trafficking may play a crucial role in the pathogenesis and survival of the malaria parasite. ADP-ribosylation factors (ARFs) are among the major components of vesicular trafficking pathways in eukaryotes. The crystal structure of ARF1 GTPase from Plasmodium falciparum has been determined in the GDP-bound conformation at 2.5 Å resolution and is compared with the structures of mammalian ARF1s. PMID:21045287

  14. Renal cortical necrosis: A rare complication of Plasmodium vivax malaria.

    PubMed

    Kumar, R; Bansal, N; Jhorawat, R; Kimmatkar, P D; Malhotra, V

    2014-11-01

    A young female with Plasmodium vivax malaria presented with anemia, hyperbilirubinemia, thrombocytopenia, and advanced renal failure. She remained anuric for more than 3 weeks. Kidney biopsy confirmed the diagnosis of acute cortical necrosis. During follow-up, she became dialysis independent, but remained in stage 4 chronic kidney disease (CKD) at 3 month. P. vivax is supposed to be benign in nature, but can lead to rare and severe complication like renal cortical necrosis and progress to CKD.

  15. Renal pathology in owl monkeys in Plasmodium falciparum vaccine trials.

    PubMed

    Iseki, M; Broderson, J R; Pirl, K G; Igarashi, I; Collins, W E; Aikawa, M

    1990-08-01

    Renal specimens of 16 owl monkeys (Aotus vociferans) were studied by light microscopy and immunohistochemistry during a vaccine trial with recombinant proteins of the ring-infected erythrocyte surface antigen (RESA) of Plasmodium falciparum. Deposition of IgG, C3, and P. falciparum antigens in the mesangium was demonstrated by the peroxidase anti-peroxidase (PAP) method. A relationship between the severity of parasitemia at the time of death and the presence of nephropathy was not apparent.

  16. Sensitive and specific DNA probe for detection of Plasmodium falciparum.

    PubMed Central

    Enea, V

    1986-01-01

    The isolation and some characteristics of a very sensitive DNA probe for the detection of Plasmodium falciparum are described. The probe is species specific and represents a large, albeit variable, fraction of the genome in all the strains tested. In addition to its immediate practical uses for the detection and quantitation of parasites, the probe defines an interesting family of repeated sequences. Images PMID:3023833

  17. Killing of Plasmodium falciparum in vitro by nitric oxide derivatives.

    PubMed Central

    Rockett, K A; Awburn, M M; Cowden, W B; Clark, I A

    1991-01-01

    We have investigated the in vitro susceptibility of the human malaria parasite Plasmodium falciparum to killing by nitric oxide and related molecules. A saturated solution of nitric oxide did not inhibit parasite growth, but two oxidation products of nitric oxide (nitrite and nitrate ions) were toxic to the parasite in millimolar concentrations. Nitrosothiol derivatives of cysteine and glutathione were found to be about a thousand times more active (50% growth inhibitory concentration, approximately 40 microM) than nitrite. PMID:1879941

  18. Structure of Plasmodium falciparum ADP-ribosylation factor 1

    SciTech Connect

    Cook, William J.; Smith, Craig D.; Senkovich, Olga; Holder, Anthony A.; Chattopadhyay, Debasish

    2011-09-26

    Vesicular trafficking may play a crucial role in the pathogenesis and survival of the malaria parasite. ADP-ribosylation factors (ARFs) are among the major components of vesicular trafficking pathways in eukaryotes. The crystal structure of ARF1 GTPase from Plasmodium falciparum has been determined in the GDP-bound conformation at 2.5 {angstrom} resolution and is compared with the structures of mammalian ARF1s.

  19. Targeting Plasmodium phosphatidylinositol 4-kinase to eliminate malaria

    PubMed Central

    Lim, Chek Shik; Lim, Siau Hoi; Roland, Jason; Simon, Oliver; Yeung, Bryan KS; Chatterjee, Arnab K; McCormack, Susan L; Manary, Micah J; Zeeman, Anne-Marie; Dechering, Koen J; Kumar, TR Santha; Henrich, Philipp P; Gagaring, Kerstin; Ibanez, Maureen; Kato, Nobutaka; Kuhen, Kelli L; Fischli, Christoph; Nagle, Advait; Rottmann, Matthias; Plouffe, David M; Bursulaya, Badry; Meister, Stephan; Rameh, Lucia; Trappe, Joerg; Haasen, Dorothea; Timmerman, Martijn; Sauerwein, Robert W; Suwanarusk, Rossarin; Russell, Bruce; Renia, Laurent; Nosten, Francois; Tully, David C; Kocken, Clemens HM; Glynne, Richard J; Bodenreider, Christophe; Fidock, David A; Diagana, Thierry T; Winzeler, Elizabeth A

    2014-01-01

    Summary Achieving the goal of malaria elimination will depend on targeting Plasmodium pathways essential across all life stages. Here, we identify a lipid kinase, phosphatidylinositol 4-kinase (PI4K), as the target of imidazopyrazines, a novel antimalarial compound class that inhibits the intracellular development of multiple Plasmodium species at each stage of infection in the vertebrate host. Imidazopyrazines demonstrate potent preventive, therapeutic, and transmission-blocking activity in rodent malaria models, are active against blood-stage field isolates of the major human pathogens, P. falciparum and P. vivax, and inhibit liver stage hypnozoites in the simian parasite P. cynomolgi. We show that imidazopyrazines exert their effect through inhibitory interaction with the ATP-binding pocket of PI4K, altering the intracellular distribution of phosphatidylinositol 4-phosphate. Collectively, our data define PI4K as a key Plasmodium vulnerability, opening up new avenues of target-based discovery to identify drugs with an ideal activity profile for the prevention, treatment and elimination of malaria. PMID:24284631

  20. Targeting Plasmodium PI(4)K to eliminate malaria.

    PubMed

    McNamara, Case W; Lee, Marcus Cs; Lim, Chek Shik; Lim, Siau Hoi; Roland, Jason; Simon, Oliver; Yeung, Bryan Ks; Chatterjee, Arnab K; McCormack, Susan L; Manary, Micah J; Zeeman, Anne-Marie; Dechering, Koen J; Kumar, Tr Santha; Henrich, Philipp P; Gagaring, Kerstin; Ibanez, Maureen; Kato, Nobutaka; Kuhen, Kelli L; Fischli, Christoph; Nagle, Advait; Rottmann, Matthias; Plouffe, David M; Bursulaya, Badry; Meister, Stephan; Rameh, Lucia; Trappe, Joerg; Haasen, Dorothea; Timmerman, Martijn; Sauerwein, Robert W; Suwanarusk, Rossarin; Russell, Bruce; Renia, Laurent; Nosten, Francois; Tully, David C; Kocken, Clemens Hm; Glynne, Richard J; Bodenreider, Christophe; Fidock, David A; Diagana, Thierry T; Winzeler, Elizabeth A

    2013-12-12

    Achieving the goal of malaria elimination will depend on targeting Plasmodium pathways essential across all life stages. Here we identify a lipid kinase, phosphatidylinositol-4-OH kinase (PI(4)K), as the target of imidazopyrazines, a new antimalarial compound class that inhibits the intracellular development of multiple Plasmodium species at each stage of infection in the vertebrate host. Imidazopyrazines demonstrate potent preventive, therapeutic, and transmission-blocking activity in rodent malaria models, are active against blood-stage field isolates of the major human pathogens P. falciparum and P. vivax, and inhibit liver-stage hypnozoites in the simian parasite P. cynomolgi. We show that imidazopyrazines exert their effect through inhibitory interaction with the ATP-binding pocket of PI(4)K, altering the intracellular distribution of phosphatidylinositol-4-phosphate. Collectively, our data define PI(4)K as a key Plasmodium vulnerability, opening up new avenues of target-based discovery to identify drugs with an ideal activity profile for the prevention, treatment and elimination of malaria.

  1. Plasmodium falciparum phosphoethanolamine methyltransferase is essential for malaria transmission

    PubMed Central

    Bobenchik, April M.; Witola, William H.; Augagneur, Yoann; Nic Lochlainn, Laura; Garg, Aprajita; Pachikara, Niseema; Choi, Jae-Yeon; Zhao, Yang O.; Usmani-Brown, Sahar; Lee, Albert; Adjalley, Sophie H.; Samanta, Swapna; Fidock, David A.; Voelker, Dennis R.; Fikrig, Erol; Ben Mamoun, Choukri

    2013-01-01

    Efficient transmission of Plasmodium species between humans and Anopheles mosquitoes is a major contributor to the global burden of malaria. Gametocytogenesis, the process by which parasites switch from asexual replication within human erythrocytes to produce male and female gametocytes, is a critical step in malaria transmission and Plasmodium genetic diversity. Nothing is known about the pathways that regulate gametocytogenesis and only few of the current drugs that inhibit asexual replication are also capable of inhibiting gametocyte development and blocking malaria transmission. Here we provide genetic and pharmacological evidence indicating that the pathway for synthesis of phosphatidylcholine in Plasmodium falciparum membranes from host serine is essential for parasite gametocytogenesis and malaria transmission. Parasites lacking the phosphoethanolamine N-methyltransferase enzyme, which catalyzes the limiting step in this pathway, are severely altered in gametocyte development, are incapable of producing mature-stage gametocytes, and are not transmitted to mosquitoes. Chemical screening identified 11 inhibitors of phosphoethanolamine N-methyltransferase that block parasite intraerythrocytic asexual replication and gametocyte differentiation in the low micromolar range. Kinetic studies in vitro as well as functional complementation assays and lipid metabolic analyses in vivo on the most promising inhibitor NSC-158011 further demonstrated the specificity of inhibition. These studies set the stage for further optimization of NSC-158011 for development of a class of dual activity antimalarials to block both intraerythrocytic asexual replication and gametocytogenesis. PMID:24145416

  2. Targeting Plasmodium PI(4)K to eliminate malaria

    NASA Astrophysics Data System (ADS)

    McNamara, Case W.; Lee, Marcus C. S.; Lim, Chek Shik; Lim, Siau Hoi; Roland, Jason; Nagle, Advait; Simon, Oliver; Yeung, Bryan K. S.; Chatterjee, Arnab K.; McCormack, Susan L.; Manary, Micah J.; Zeeman, Anne-Marie; Dechering, Koen J.; Kumar, T. R. Santha; Henrich, Philipp P.; Gagaring, Kerstin; Ibanez, Maureen; Kato, Nobutaka; Kuhen, Kelli L.; Fischli, Christoph; Rottmann, Matthias; Plouffe, David M.; Bursulaya, Badry; Meister, Stephan; Rameh, Lucia; Trappe, Joerg; Haasen, Dorothea; Timmerman, Martijn; Sauerwein, Robert W.; Suwanarusk, Rossarin; Russell, Bruce; Renia, Laurent; Nosten, Francois; Tully, David C.; Kocken, Clemens H. M.; Glynne, Richard J.; Bodenreider, Christophe; Fidock, David A.; Diagana, Thierry T.; Winzeler, Elizabeth A.

    2013-12-01

    Achieving the goal of malaria elimination will depend on targeting Plasmodium pathways essential across all life stages. Here we identify a lipid kinase, phosphatidylinositol-4-OH kinase (PI(4)K), as the target of imidazopyrazines, a new antimalarial compound class that inhibits the intracellular development of multiple Plasmodium species at each stage of infection in the vertebrate host. Imidazopyrazines demonstrate potent preventive, therapeutic, and transmission-blocking activity in rodent malaria models, are active against blood-stage field isolates of the major human pathogens P. falciparum and P. vivax, and inhibit liver-stage hypnozoites in the simian parasite P. cynomolgi. We show that imidazopyrazines exert their effect through inhibitory interaction with the ATP-binding pocket of PI(4)K, altering the intracellular distribution of phosphatidylinositol-4-phosphate. Collectively, our data define PI(4)K as a key Plasmodium vulnerability, opening up new avenues of target-based discovery to identify drugs with an ideal activity profile for the prevention, treatment and elimination of malaria.

  3. Superinfection in malaria: Plasmodium shows its iron will

    PubMed Central

    Portugal, Sílvia; Drakesmith, Hal; Mota, Maria M

    2011-01-01

    After the bite of a malaria-infected mosquito, the Plasmodium sporozoite infects liver cells and produces thousands of merozoites, which then infect red blood cells, causing malaria. In malaria-endemic areas, several hundred infected mosquitoes can bite an individual each year, increasing the risk of superinfection. However, in infants that are yet to acquire immunity, superinfections are infrequent. We have recently shown that blood-stage parasitaemia, above a minimum threshold, impairs the growth of a subsequent sporozoite infection of liver cells. Blood-stage parasites stimulate the production of the host iron-regulatory factor hepcidin, which redistributes iron away from hepatocytes, reducing the development of the iron-dependent liver stage. This could explain why Plasmodium superinfection is not often found in young nonimmune children. Here, we discuss the impact that such protection from superinfection might have in epidemiological settings or in programmes for controlling malaria, as well as how the induction of hepcidin and redistribution of iron might influence anaemia and the outcome of non-Plasmodium co-infections. PMID:22081142

  4. Plasmodium vivax merozoite surface protein 8 cloning, expression, and characterisation.

    PubMed

    Perez-Leal, Oscar; Sierra, Adriana Y; Barrero, Carlos A; Moncada, Camilo; Martinez, Pilar; Cortes, Jimena; Lopez, Yolanda; Torres, Elizabeth; Salazar, Luz M; Patarroyo, Manuel A

    2004-11-26

    Plasmodium vivax, one of the four parasite species causing malaria in humans, is the most widespread throughout the world, leading to nearly 80 million cases per year, mainly in Latin-America and Asia. An open reading frame encoding the Plasmodium falciparum merozoite surface protein 8 P. vivax homologue has been identified in the present study by screening the current data obtained from this parasite's partially sequenced genome. This new protein contains 487 amino-acids, two epidermal growth factor like domains, hydrophobic regions at the N- and C-termini compatible with a signal peptide, and a glycosylphosphatidylinositol anchor site, respectively. This gene's transcription and its encoded protein expression have been assessed, as well as its recognition by P. vivax-infected patients' sera. Based on this recognition, and a previous study showing that mice immunised with the Plasmodium yoelii homologous protein were protected, we consider the PvMSP8 a good candidate to be included in a multi-stage multi-antigen P. vivax vaccine.

  5. Acute kidney injury associated with Plasmodium malariae infection.

    PubMed

    Badiane, Aida S; Diongue, Khadim; Diallo, Seydou; Ndongo, Aliou A; Diedhiou, Cyrille K; Deme, Awa B; Ma, Diallo; Ndiaye, Mouhamadou; Seck, Mame C; Dieng, Therese; Ndir, Omar; Mboup, Souleymane; Ndiaye, Daouda

    2014-06-07

    According to current estimates, Plasmodium malariae is not very common in Senegal, as more than 98% of malaria cases are suspected to be due to Plasmodium falciparum. However, it is possible that other malarial species are being under-reported or misdiagnosed. This is a report of a case of P. malariae in a 30-year-old man previously hospitalized with acute kidney injury after treatment with quinine and re-hospitalized three months later. He was diagnosed with renal cortical necrosis post malaria treatment. Plasmodium malariae was identified with light microscope and confirmed using species-specific small-subunit rRNA (ssrRNA) amplification.The patient was treated for malaria with intravenous quinine for seven days, followed by three days of oral treatment; the bacterial infection was treated using ceftriaxone during the first hospitalization and ciprofloxacin associated with ceftriaxone the second time. He also had four rounds of dialysis after which he partially recovered the renal function. Given the complications that can be caused by P. malariae infection, it should be systematically looked for, even if the predominant species is P. falciparum in Senegal.

  6. [Therapeutic response of Plasmodium vivax to chloroquine in Bolivia].

    PubMed

    Añez, Arletta; Navarro-Costa, Dennis; Yucra, Omar; Garnica, Cecilia; Melgar, Viviana; Moscoso, Manuel; Arteaga, Ricardo; Nakao, Gladys

    2012-01-01

    Knowledge of the therapeutic efficacy of chloroquine for Plasmodium vivax infections improves the capacity for surveillance of anti-malarial drug resistance. The therapeutic efficacy of chloroquine as treatment was evaluated for uncomplicated Plasmodium vivax malaria in Bolivia. An in vivo efficacy study of chloroquine was undertaken in three regions of Bolivia--Riberalta, Guayaramerín and Yacuiba. Two hundred and twenty-three patients (84, 80, and 59 in the three regions, respectively) aged over 5 years old were administered with chloroquine (25 mg/kg/three days) and followed for 28 days. Blood levels of chloroquine and desethylchloroquine were measured on day 2 and on the day of reappearance of parasitemia. The cumulative incidence of treatment failure was calculated using the Kaplan and Meier survival analysis. The mean parasitemias (asexual) on day 0 were 6,147 parasites/μl of blood in the Riberalta population, 4,251 in Guayaramerín and 5,214 in Yacuiba. The average blood concentrations of chloroquine-desethylchloroquine during day 2 were 783, 817, and 815 ng/ml, respectively. No treatment failures were observed in Yacuiba, whereas in Riberalta and Guayaramerín, the frequencies of treatment failures were 6.2% and 10%. Blood levels of chloroquine and desethylchloroquine in patients with treatment failure showed values below 70 ng/ml on the day of reappearance of parasitemia. Resistance of Plasmodium vivax to chloroquine was not demonstrated in three regions of Bolivia.

  7. Plasmodium ookinetes coopt mammalian plasminogen to invade the mosquito midgut

    PubMed Central

    Ghosh, Anil K.; Coppens, Isabelle; Gårdsvoll, Henrik; Ploug, Michael; Jacobs-Lorena, Marcelo

    2011-01-01

    Ookinete invasion of the mosquito midgut is an essential step for the development of the malaria parasite in the mosquito. Invasion involves recognition between a presumed mosquito midgut receptor and an ookinete ligand. Here, we show that enolase lines the ookinete surface. An antienolase antibody inhibits oocyst development of both Plasmodium berghei and Plasmodium falciparum, suggesting that enolase may act as an invasion ligand. Importantly, we demonstrate that surface enolase captures plasminogen from the mammalian blood meal via its lysine motif (DKSLVK) and that this interaction is essential for midgut invasion, because plasminogen depletion leads to a strong inhibition of oocyst formation. Although addition of recombinant WT plasminogen to depleted serum rescues oocyst formation, recombinant inactive plasminogen does not, thus emphasizing the importance of plasmin proteolytic activity for ookinete invasion. The results support the hypothesis that enolase on the surface of Plasmodium ookinetes plays a dual role in midgut invasion: by acting as a ligand that interacts with the midgut epithelium and, further, by capturing plasminogen, whose conversion to active plasmin promotes the invasion process. PMID:21949403

  8. Primaquine for reducing Plasmodium falciparum transmission.

    PubMed

    Graves, Patricia M; Gelband, Hellen; Garner, Paul

    2012-09-12

    Mosquitoes become infected with malaria when they ingest gametocyte stages of the parasite from the blood of a human host. Plasmodium falciparum gametocytes are sensitive to the drug primaquine (PQ). The World Health Organization (WHO) recommends giving a single dose or short course of PQ alongside primary treatment for people ill with P. falciparum infection to reduce malaria transmission. Gametocytes themselves cause no symptoms, so this intervention does not directly benefit individuals. PQ causes haemolysis in some people with glucose-6-phosphate dehydrogenase (G6PD) deficiency so may not be safe.   To assess whether a single dose or short course of PQ added to treatments for malaria caused by P. falciparum infection reduces malaria transmission and is safe. We searched the following databases up to 10 April 2012 for studies: the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in The Cochrane Library; MEDLINE; EMBASE; LILACS; metaRegister of Controlled Trials (mRCT) and the WHO trials search portal using 'malaria*', 'falciparum', and 'primaquine' as search terms. In addition, we searched conference proceedings and reference lists of included studies, and we contacted likely researchers and organizations for relevant trials. Trials of mass treatment of whole populations (or actively detected fever or malaria cases within such populations) with antimalarial drugs, compared to treatment with the same drug plus PQ; or patients with clinical malaria being treated for malaria at health facilities randomized to short course/single dose PQ versus no PQ. Two authors (PMG and HG) independently screened all abstracts, applied inclusion criteria, and abstracted data. We sought data on the effect of PQ on malaria transmission intensity, participant infectiousness, the number of participants with gametocytes, and gametocyte density over time. We stratified results by primary treatment drug as

  9. Ex Vivo Activity of Endoperoxide Antimalarials, Including Artemisone and Arterolane, against Multidrug-Resistant Plasmodium falciparum Isolates from Cambodia

    DTIC Science & Technology

    2014-10-01

    of artemisinin combination therapies (ACTs) to treat artemisinin-resistant Plasmodium falciparum malaria . We conducted blinded ex vivo activity...Optimizing the HRP-2 in vitro malaria drug susceptibility assay using a reference clone to improve comparisons of Plasmodium falciparum field isolates... malaria SYBR green I fluorescence (MSF) drug sensitivity tests in Plasmodium falciparum refer- ence clones and fresh ex vivo field isolates from

  10. A bioinformatic survey of RNA-binding proteins in Plasmodium.

    PubMed

    Reddy, B P Niranjan; Shrestha, Sony; Hart, Kevin J; Liang, Xiaoying; Kemirembe, Karen; Cui, Liwang; Lindner, Scott E

    2015-11-02

    The malaria parasites in the genus Plasmodium have a very complicated life cycle involving an invertebrate vector and a vertebrate host. RNA-binding proteins (RBPs) are critical factors involved in every aspect of the development of these parasites. However, very few RBPs have been functionally characterized to date in the human parasite Plasmodium falciparum. Using different bioinformatic methods and tools we searched P. falciparum genome to list and annotate RBPs. A representative 3D models for each of the RBD domain identified in P. falciparum was created using I-TESSAR and SWISS-MODEL. Microarray and RNAseq data analysis pertaining PfRBPs was performed using MeV software. Finally, Cytoscape was used to create protein-protein interaction network for CITH-Dozi and Caf1-CCR4-Not complexes. We report the identification of 189 putative RBP genes belonging to 13 different families in Plasmodium, which comprise 3.5% of all annotated genes. Almost 90% (169/189) of these genes belong to six prominent RBP classes, namely RNA recognition motifs, DEAD/H-box RNA helicases, K homology, Zinc finger, Puf and Alba gene families. Interestingly, almost all of the identified RNA-binding helicases and KH genes have cognate homologs in model species, suggesting their evolutionary conservation. Exploration of the existing P. falciparum blood-stage transcriptomes revealed that most RBPs have peak mRNA expression levels early during the intraerythrocytic development cycle, which taper off in later stages. Nearly 27% of RBPs have elevated expression in gametocytes, while 47 and 24% have elevated mRNA expression in ookinete and asexual stages. Comparative interactome analyses using human and Plasmodium protein-protein interaction datasets suggest extensive conservation of the PfCITH/PfDOZI and PfCaf1-CCR4-NOT complexes. The Plasmodium parasites possess a large number of putative RBPs belonging to most of RBP families identified so far, suggesting the presence of extensive post

  11. Molecular epidemiology of Plasmodium vivax and Plasmodium falciparum malaria among Duffy-positive and Duffy-negative populations in Ethiopia.

    PubMed

    Lo, Eugenia; Yewhalaw, Delenasaw; Zhong, Daibin; Zemene, Endalew; Degefa, Teshome; Tushune, Kora; Ha, Margaret; Lee, Ming-Chieh; James, Anthony A; Yan, Guiyun

    2015-02-19

    Malaria is the most prevalent communicable disease in Ethiopia, with 75% of the country's landmass classified as endemic for malaria. Accurate information on the distribution and clinical prevalence of Plasmodium vivax and Plasmodium falciparum malaria in endemic areas, as well as in Duffy-negative populations, is essential to develop integrated control strategies. A total of 390 and 416 community and clinical samples, respectively, representing different localities and age groups across Ethiopia were examined. Malaria prevalence was estimated using nested PCR of the 18S rRNA region. Parasite gene copy number was measured by quantitative real-time PCR and compared between symptomatic and asymptomatic samples, as well as between children/adolescents and adults from the local community. An approximately 500-bp segment of the human DARC gene was amplified and sequenced to identify Duffy genotype at the -33rd nucleotide position for all the clinical and community samples. Plasmodium vivax prevalence was higher in the south while P. falciparum was higher in the north. The prevalence of P. vivax and P. falciparum malaria is the highest in children compared to adolescents and adults. Four P. vivax infections were detected among the Duffy-negative samples. Samples from asymptomatic individuals show a significantly lower parasite gene copy number than those from symptomatic infections for P. vivax and P. falciparum. Geographical and age differences influence the distribution of P. vivax and P. falciparum malaria in Ethiopia. These findings offer evidence-based guidelines in targeting malaria control efforts in the country.

  12. Primary structure of the merozoite surface antigen 1 of Plasmodium vivax reveals sequences conserved between different Plasmodium species.

    PubMed Central

    del Portillo, H A; Longacre, S; Khouri, E; David, P H

    1991-01-01

    Merozoite surface antigen 1 (MSA1) of several species of plasmodia has been shown to be a promising candidate for a vaccine directed against the asexual blood stages of malaria. We report the cloning and characterization of the MSA1 gene of the human malaria parasite Plasmodium vivax. This gene, which we call Pv200, encodes a polypeptide of 1726 amino acids and displays features described for MSA1 genes of other species, such as signal peptide and anchoring sequences, conserved cysteine residues, number of potential N-glycosylation sites, and repeats consisting here of 23 glutamine residues in a row. When the nucleotide and deduced amino acid sequences of the MSA1 of P. vivax are compared to those of another human malaria parasite, Plasmodium falciparum, and to those of the rodent parasite Plasmodium yoelii, 10 regions of high amino acid similarity are observed despite the very different dG + dC contents of the corresponding genes. All of the interspecies conserved regions reside within the conserved or semiconserved blocks delimited by the sequences of different alleles of the MSA1 gene of P. falciparum. Images PMID:2023952

  13. Molecular Detection of Plasmodium malariae/Plasmodium brasilianum in Non-Human Primates in Captivity in Costa Rica.

    PubMed

    Fuentes-Ramírez, Alicia; Jiménez-Soto, Mauricio; Castro, Ruth; Romero-Zuñiga, Juan José; Dolz, Gaby

    2017-01-01

    One hundred and fifty-two blood samples of non-human primates of thirteen rescue centers in Costa Rica were analyzed to determine the presence of species of Plasmodium using thick blood smears, semi-nested multiplex polymerase chain reaction (SnM-PCR) for species differentiation, cloning and sequencing for confirmation. Using thick blood smears, two samples were determined to contain the Plasmodium malariae parasite, with SnM-PCR, a total of five (3.3%) samples were positive to P. malariae, cloning and sequencing confirmed both smear samples as P. malariae. One sample amplified a larger and conserved region of 18S rDNA for the genus Plasmodium and sequencing confirmed the results obtained microscopically and through SnM-PCR tests. Sequencing and construction of a phylogenetic tree of this sample revealed that the P. malariae/P. brasilianum parasite (GenBank KU999995) found in a howler monkey (Alouatta palliata) is identical to that recently reported in humans in Costa Rica. The SnM-PCR detected P. malariae/P. brasilianum parasite in different non-human primate species in captivity and in various regions of the southern Atlantic and Pacific coast of Costa Rica. The similarity of the sequences of parasites found in humans and a monkey suggests that monkeys may be acting as reservoirs of P.malariae/P. brasilianum, for which reason it is important, to include them in control and eradication programs.

  14. Molecular Detection of Plasmodium malariae/Plasmodium brasilianum in Non-Human Primates in Captivity in Costa Rica

    PubMed Central

    Fuentes-Ramírez, Alicia; Jiménez-Soto, Mauricio; Castro, Ruth; Romero-Zuñiga, Juan José

    2017-01-01

    One hundred and fifty-two blood samples of non-human primates of thirteen rescue centers in Costa Rica were analyzed to determine the presence of species of Plasmodium using thick blood smears, semi-nested multiplex polymerase chain reaction (SnM-PCR) for species differentiation, cloning and sequencing for confirmation. Using thick blood smears, two samples were determined to contain the Plasmodium malariae parasite, with SnM-PCR, a total of five (3.3%) samples were positive to P. malariae, cloning and sequencing confirmed both smear samples as P. malariae. One sample amplified a larger and conserved region of 18S rDNA for the genus Plasmodium and sequencing confirmed the results obtained microscopically and through SnM-PCR tests. Sequencing and construction of a phylogenetic tree of this sample revealed that the P. malariae/P. brasilianum parasite (GenBank KU999995) found in a howler monkey (Alouatta palliata) is identical to that recently reported in humans in Costa Rica. The SnM-PCR detected P. malariae/P. brasilianum parasite in different non-human primate species in captivity and in various regions of the southern Atlantic and Pacific coast of Costa Rica. The similarity of the sequences of parasites found in humans and a monkey suggests that monkeys may be acting as reservoirs of P.malariae/P. brasilianum, for which reason it is important, to include them in control and eradication programs. PMID:28125696

  15. Sequential Plasmodium chabaudi and Plasmodium berghei infections provide a novel model of severe malarial anemia.

    PubMed

    Harris, Juliana V; Bohr, Tiffany M; Stracener, Catherine; Landmesser, Mary E; Torres, Vladimir; Mbugua, Amos; Moratz, Chantal; Stoute, José A

    2012-09-01

    Lack of an adequate animal model of Plasmodium falciparum severe malarial anemia (SMA) has hampered the understanding of this highly lethal condition. We developed a model of SMA by infecting C57BL/6 mice with P. chabaudi followed after recovery by P. berghei infection. P. chabaudi/P. berghei-infected mice had an initial 9- to 10-day phase of relatively low parasitemia and severe anemia, followed by a second phase of hyperparasitemia, more profound anemia, reticulocytosis, and death 14 to 21 days after infection. P. chabaudi/P. berghei-infected animals had more intense splenic hematopoiesis, higher interleukin-10 (IL-10)/tumor necrosis factor alpha and IL-12/gamma interferon (IFN-γ) ratios, and higher antibody levels against P. berghei and P. chabaudi antigens than P. berghei-infected or P. chabaudi-recovered animals. Early treatment with chloroquine or artesunate did not prevent the anemia, suggesting that the bulk of red cell destruction was not due to the parasite. Red cells from P. chabaudi/P. berghei-infected animals had increased surface IgG and C3 by flow cytometry. However, C3(-/-) mice still developed anemia. Tracking of red cells labeled ex vivo and in vivo and analysis of frozen tissue sections by immunofluorescence microscopy showed that red cells from P. chabaudi/P. berghei-infected animals were removed at an accelerated rate in the liver by erythrophagocytosis. This model is practical and reproducible, and its similarities with P. falciparum SMA in humans makes it an appealing system with which to study the pathogenesis of this condition and explore potential immunomodulatory interventions.

  16. [Nuclei in the plasmodium of Intoshia variabili (Orthonectida) as revealed by DAPI staining].

    PubMed

    Sliusarev, G S; Manylov, O G; Cherkasov, A S

    2002-01-01

    DAPI staining of wholeamounts was used to reveal the parasitic plasmodium of the orthonectid Intoshia variabili in its host, the turbellarian Macrorhynchus crocea. The nuclei of the parasite differ drastically from those of the host in size, morphology, and the estimated DNA content. Our findings indirectly support the idea that the orthonectid plasmodium is a distinct parasitic organism, rather than modified host cells.

  17. Human Plasmodium knowlesi Infection Detected by Rapid Diagnostic Tests for Malaria

    PubMed Central

    van Hellemond, Jaap J.; Rutten, Marijke; Koelewijn, Rob; Zeeman, Anne-Marie; Verweij, Jaco J.; Wismans, Pieter J.; Kocken, Clemens H.

    2009-01-01

    We describe a PCR-confirmed case of Plasmodium knowlesi infection with a high parasitemia level and clinical signs of severe malaria in a migrant worker from Malaysian Borneo in the Netherlands. Investigations showed that commercially available rapid antigen tests for detection of human Plasmodium infections can detect P. knowlesi infections in humans. PMID:19788819

  18. Innexin AGAP001476 Is Critical for Mediating Anti-Plasmodium Responses in Anopheles Mosquitoes

    PubMed Central

    Li, Michelle W. M.; Wang, Jiuling; Zhao, Yang O.; Fikrig, Erol

    2014-01-01

    The Toll and IMD pathways are known to be induced upon Plasmodium berghei and Plasmodium falciparum infection, respectively. It is unclear how Plasmodium or other pathogens in the blood meal and their invasion of the midgut epithelium would trigger the innate immune responses in immune cells, in particular hemocytes. Gap junctions, which can mediate both cell-to-cell and cell-to-extracellular communication, may participate in this signal transduction. This study examined whether innexins, gap junction proteins in insects, are involved in anti-Plasmodium responses in Anopheles gambiae. Inhibitor studies using carbenoxolone indicated that blocking innexons resulted in an increase in Plasmodium oocyst number and infection prevalence. This was accompanied by a decline in TEP1 levels in carbenoxolone-treated mosquitoes. Innexin AGAP001476 mRNA levels in midguts were induced during Plasmodium infection and a knockdown of AGAP001476, but not AGAP006241, caused an induction in oocyst number. Silencing AGAP001476 caused a concurrent increase in vitellogenin levels, a TEP1 inhibitor, in addition to a reduced level of TEP1-LRIM1-APL1C complex in hemolymph. Both vitellogenin and TEP1 are regulated by Cactus under the Toll pathway. Simultaneous knockdown of cactus and AGAP001476 failed to reverse the near refractoriness induced by the knockdown of cactus, suggesting that the AGAP001476-mediated anti-Plasmodium response is Cactus-dependent. These data demonstrate a critical role for innexin AGAP001476 in mediating innate immune responses against Plasmodium through Toll pathway in mosquitoes. PMID:25035430

  19. Innexin AGAP001476 is critical for mediating anti-Plasmodium responses in Anopheles mosquitoes.

    PubMed

    Li, Michelle W M; Wang, Jiuling; Zhao, Yang O; Fikrig, Erol

    2014-09-05

    The Toll and IMD pathways are known to be induced upon Plasmodium berghei and Plasmodium falciparum infection, respectively. It is unclear how Plasmodium or other pathogens in the blood meal and their invasion of the midgut epithelium would trigger the innate immune responses in immune cells, in particular hemocytes. Gap junctions, which can mediate both cell-to-cell and cell-to-extracellular communication, may participate in this signal transduction. This study examined whether innexins, gap junction proteins in insects, are involved in anti-Plasmodium responses in Anopheles gambiae. Inhibitor studies using carbenoxolone indicated that blocking innexons resulted in an increase in Plasmodium oocyst number and infection prevalence. This was accompanied by a decline in TEP1 levels in carbenoxolone-treated mosquitoes. Innexin AGAP001476 mRNA levels in midguts were induced during Plasmodium infection and a knockdown of AGAP001476, but not AGAP006241, caused an induction in oocyst number. Silencing AGAP001476 caused a concurrent increase in vitellogenin levels, a TEP1 inhibitor, in addition to a reduced level of TEP1-LRIM1-APL1C complex in hemolymph. Both vitellogenin and TEP1 are regulated by Cactus under the Toll pathway. Simultaneous knockdown of cactus and AGAP001476 failed to reverse the near refractoriness induced by the knockdown of cactus, suggesting that the AGAP001476-mediated anti-Plasmodium response is Cactus-dependent. These data demonstrate a critical role for innexin AGAP001476 in mediating innate immune responses against Plasmodium through Toll pathway in mosquitoes.

  20. New type of SSUrDNA sequence was detected from both Plasmodium ovale curtisi and Plasmodium ovale wallikeri samples

    PubMed Central

    2014-01-01

    Background Plasmodium ovale is relatively unfamiliar to Chinese staff engaged in malaria diagnosis. In 2013, dried blood spots of four unidentified but suspected ovale malaria samples were sent to the National Malaria Reference Laboratory (NMRL) for reconfirmation. Methods Partial and complete, small, subunit ribosomal DNA (SSU rDNA) sequences of four samples were obtained with PCR-cloning-sequencing method. Obtained sequences were analyzed by aligning with each other and with nine SSU rDNA sequences of six known Plasmodium parasites. A phylogenetic tree was constructed based on complete SSU rDNA sequences and 12 same gene sequences derived from six known Plasmodium parasites and three Babesia parasites. Primary structure of conservative and variable regions of variant sequences was determined also by comparing them with those of six known Plasmodium parasites. To confirm their existence in genome, they were redetected with primers matching their variable regions. PCR systems aimed to roughly detect any eukaryotes and prokaryotes respectively were also applied to search for other pathogens in one of four patients. Results Totally, 19 partial and 23 complete SSU rDNA sequences obtained from four samples. Except eight variant sequences, similarities among sequences from same DNA sample were in general high (more than 98%). The phylogenetic analysis revealed that three cases were infected by P. ovale wallikeri and one by P. ovale curtisi. Four of the variant sequences which obtained from four samples relatively showed high similarities with each other (98.5%-100%). Identical variant sequences actually could be re-obtained from each DNA sample. Their primary structure of conservative and variable regions showed quite fit with that of six known Plasmodium parasites. The test for prokaryote pathogens showed negative and the tests for eukaryotes only found DNA sequences of Human and P. ovale parasites. Conclusion Both P. ovale wallikeri and P. ovale curtisi infections are

  1. The Plasmodium apicoplast genome: conserved structure and close relationship of P. ovale to rodent malaria parasites.

    PubMed

    Arisue, Nobuko; Hashimoto, Tetsuo; Mitsui, Hideya; Palacpac, Nirianne M Q; Kaneko, Akira; Kawai, Satoru; Hasegawa, Masami; Tanabe, Kazuyuki; Horii, Toshihiro

    2012-09-01

    Apicoplast, a nonphotosynthetic plastid derived from secondary symbiotic origin, is essential for the survival of malaria parasites of the genus Plasmodium. Elucidation of the evolution of the apicoplast genome in Plasmodium species is important to better understand the functions of the organelle. However, the complete apicoplast genome is available for only the most virulent human malaria parasite, Plasmodium falciparum. Here, we obtained the near-complete apicoplast genome sequences from eight Plasmodium species that infect a wide variety of vertebrate hosts and performed structural and phylogenetic analyses. We found that gene repertoire, gene arrangement, and other structural attributes were highly conserved. Phylogenetic reconstruction using 30 protein-coding genes of the apicoplast genome inferred, for the first time, a close relationship between P. ovale and rodent parasites. This close relatedness was robustly supported using multiple evolutionary assumptions and models. The finding suggests that an ancestral host switch occurred between rodent and human Plasmodium parasites.

  2. Loop-Mediated Isothermal Amplification Assay for Identification of Five Human Plasmodium Species in Malaysia.

    PubMed

    Lau, Yee-Ling; Lai, Meng-Yee; Fong, Mun-Yik; Jelip, Jenarun; Mahmud, Rohela

    2016-02-01

    The lack of rapid, affordable, and accurate diagnostic tests represents the primary hurdle affecting malaria surveillance in resource- and expertise-limited areas. Loop-mediated isothermal amplification (LAMP) is a sensitive, rapid, and cheap diagnostic method. Five species-specific LAMP assays were developed based on 18S rRNA gene. Sensitivity and specificity of LAMP results were calculated as compared with microscopic examination and nested polymerase chain reaction. LAMP reactions were highly sensitive with the detection limit of one copy for Plasmodium vivax, Plasmodium falciparum, and Plasmodium malariae and 10 copies for Plasmodium knowlesi and Plasmodium ovale. LAMP positively detected all human malaria species in all positive samples (N = 134; sensitivity = 100%) within 35 minutes. All negative samples were not amplified by LAMP (N = 67; specificity = 100%). LAMP successfully detected two samples with very low parasitemia. LAMP may offer a rapid, simple, and reliable test for the diagnosis of malaria in areas where malaria is prevalent.

  3. Avian malaria on Madagascar: bird hosts and putative vector mosquitoes of different Plasmodium lineages.

    PubMed

    Schmid, Sandrine; Dinkel, Anke; Mackenstedt, Ute; Tantely, Michaël Luciano; Randrianambinintsoa, Fano José; Boyer, Sébastien; Woog, Friederike

    2017-01-05

    Avian malaria occurs almost worldwide and is caused by Haemosporida parasites (Plasmodium, Haemoproteus and Leucocytozoon). Vectors such as mosquitoes, hippoboscid flies or biting midges are required for the transmission of these parasites. There are few studies about avian malaria parasites on Madagascar but none about suitable vectors. To identify vectors of avian Plasmodium parasites on Madagascar, we examined head, thorax and abdomen of 418 mosquitoes from at least 18 species using a nested PCR method to amplify a 524 bp fragment of the haemosporidian mitochondrial cytochrome b gene. Sequences obtained were then compared with a large dataset of haemosporidian sequences detected in 45 different bird species (n = 686) from the same area in the Maromizaha rainforest. Twenty-one mosquitoes tested positive for avian malaria parasites. Haemoproteus DNA was found in nine mosquitoes (2.15%) while Plasmodium DNA was found in 12 mosquitoes (2.87%). Seven distinct lineages were identified among the Plasmodium DNA samples. Some lineages were also found in the examined bird samples: Plasmodium sp. WA46 (EU810628.1) in the Madagascar bulbul, Plasmodium sp. mosquito 132 (AB308050.1) in 15 bird species belonging to eight families, Plasmodium sp. PV12 (GQ150194.1) in eleven bird species belonging to eight families and Plasmodium sp. P31 (DQ839060.1) was found in three weaver bird species. This study provides the first insight into avian malaria transmission in the Maromizaha rainforest in eastern Madagascar. Five Haemoproteus lineages and seven Plasmodium lineages were detected in the examined mosquitoes. Complete life-cycles for the specialist lineages WA46 and P31 and for the generalist lineages mosquito132 and PV12 of Plasmodium are proposed. In addition, we have identified for the first time Anopheles mascarensis and Uranotaenia spp. as vectors for avian malaria and offer the first description of vector mosquitoes for avian malaria in Madagascar.

  4. Malaria risk factor assessment using active and passive surveillance data from Aceh Besar, Indonesia, a low endemic, malaria elimination setting with Plasmodium knowlesi, Plasmodium vivax, and Plasmodium falciparum.

    PubMed

    Herdiana, Herdiana; Cotter, Chris; Coutrier, Farah N; Zarlinda, Iska; Zelman, Brittany W; Tirta, Yusrifar Kharisma; Greenhouse, Bryan; Gosling, Roly D; Baker, Peter; Whittaker, Maxine; Hsiang, Michelle S

    2016-09-13

    As malaria transmission declines, it becomes more geographically focused and more likely due to asymptomatic and non-falciparum infections. To inform malaria elimination planning in the context of this changing epidemiology, local assessments on the risk factors for malaria infection are necessary, yet challenging due to the low number of malaria cases. A population-based, cross-sectional study was performed using passive and active surveillance data collected in Aceh Besar District, Indonesia from 2014 to 2015. Malaria infection was defined as symptomatic polymerase chain reaction (PCR)-confirmed infection in index cases reported from health facilities, and asymptomatic or symptomatic PCR-confirmed infection identified in reactive case detection (RACD). Potential risk factors for any infection, species-specific infection, or secondary-case detection in RACD were assessed through questionnaires and evaluated for associations. Nineteen Plasmodium knowlesi, 12 Plasmodium vivax and six Plasmodium falciparum cases were identified passively, and 1495 community members screened in RACD, of which six secondary cases were detected (one P. knowlesi, three P. vivax, and two P. falciparum, with four being asymptomatic). Compared to non-infected subjects screened in RACD, cases identified through passive or active surveillance were more likely to be male (AOR 12.5, 95 % CI 3.0-52.1), adult (AOR 14.0, 95 % CI 2.2-89.6 for age 16-45 years compared to <15 years), have visited the forest in the previous month for any reason (AOR 5.6, 95 % CI 1.3-24.2), and have a workplace near or in the forest and requiring overnight stays (AOR 7.9, 95 % CI 1.6-39.7 compared to workplace not near or in the forest). Comparing subjects with infections of different species, differences were observed in sub-district of residence and other demographic and behavioural factors. Among subjects screened in RACD, cases compared to non-cases were more likely to be febrile and reside within 100 m of

  5. Distinct temporal recruitment of Plasmodium alveolins to the subpellicular network.

    PubMed

    Tremp, Annie Z; Al-Khattaf, Fatimah S; Dessens, Johannes T

    2014-11-01

    The zoite stages of malaria parasites (merozoite, ookinete and sporozoite) possess a distinctive cortical structure termed the pellicle, which is defined by a double membrane layer named the inner membrane complex (IMC). The IMC is supported by a cytoskeleton of intermediate filaments, termed the subpellicular network (SPN). Plasmodium IMC1 proteins, or alveolins, make up a conserved family of structurally related proteins that comprise building blocks of the SPN. Here, using green fluorescent protein (GFP) tagging in P. berghei, we show that the alveolins PbIMC1c and PbIMC1e are expressed in all three zoite stages. Our data reveal that PbIMC1e is assembled into the SPN concurrent with pellicle development, while PbIMC1c is assembled after pellicle formation. In the sexual stages, these processes are accompanied by different gene expressions from maternal and paternal alleles: PbIMC1e is expressed uniquely from the maternal allele, while PbIMC1c is expressed from the maternal allele in gametocytes, but from both parental alleles during ookinete development. These findings establish biogenesis of the cortical cytoskeleton in Plasmodium to be a complex and dynamic process, involving distinct parental gene expression and chronological recruitment of its protein constituents. While allelic replacement of the pbimc1c and pbimc1e genes with GFP-tagged versions was readily achieved using double crossover homologous recombination, attempts to disrupt these genes by this strategy only resulted in the integration of the selectable marker and GFP reporter into non-specific genomic locations. The recurrent inability to disrupt these genes provides the first genetic evidence that alveolins are necessary for asexual blood-stage parasite development in Plasmodium.

  6. [Monkey malaria (Plasmodium knowlesi infection) after travelling to Thailand].

    PubMed

    Kroidl, Inge; Seilmaier, Michael; Berens-Riha, Nicole; Bretzel, Gisela; Wendtner, Clemens; Löscher, Thomas

    2015-05-01

    A case of malaria caused by Plasmodium knowlesi is described in a 52-year-old female German traveler after returning from Thailand. P. knowlesi is a parasite of macaques in Southeast Asia and has been recognized in recent years as an important and probably increasing cause of human malaria in some areas. At least 16 cases in international travelers have been published so far. This includes four cases imported to Germany. All German patients visited forested areas in Southern Thailand inhabited by the natural monkey host prior to their illness. Most cases diagnosed in endemic areas present as mild disease. However in some patients P. knowlesi may take a severe and life-threatening course. Diagnosis is usually is based on microscopy whereas rapid tests are not reliable. However, microscopic differentiation of P. knowlesi from other plasmodium species (eg, P. malariae, P. falciparum) is difficult, especially when parasitemia is low. Thus PCR methods are required for definite species determination. Changing endemicity as well as changing tourism patterns such as the trend towards eco-tourism might increase the risk of infection for travelers even in areas which are considered as low endemic for malaria. Malaria has to be considered in all febrile patients returning from endemic areas. In Southeast Asia this has to include Plasmodium knowlesi infection. Especially if microscopy suggests P. falciparum/P. malariae double infection, or when results indicate P. malariae but the clinical presentation differs from that of quartan malaria (eg, daily fever), diagnostic procedures for P. knowlesi should be initiated. Currently available rapid diagnostic tests are not reliable for the detection of P. knowlesi. The definite diagnosis of P. knowlesi infection usually requires PCR techniques Changing tourism patterns such as the trend towards eco-tourism might increase the risk of infection for travelers even in low prevalence areas.

  7. Clinical and Laboratory Features of Human Plasmodium knowlesi Infection

    PubMed Central

    Daneshvar, Cyrus; Davis, Timothy M. E.; Cox-Singh, Janet; Rafa’ee, Mohammad Zakri; Zakaria, Siti Khatijah; Divis, Paul C. S.; Singh, Balbir

    2010-01-01

    Background Plasmodium knowlesi is increasingly recognized as a cause of human malaria in Southeast Asia but there are no detailed prospective clinical studies of naturally acquired infections. Methods In a systematic study of the presentation and course of patients with acute P. knowlesi infection, clinical and laboratory data were collected from previously untreated, nonpregnant adults admitted to the hospital with polymerase chain reaction–confirmed acute malaria at Kapit Hospital (Sarawak, Malaysia) from July 2006 through February 2008. Results Of 152 patients recruited, 107 (70%) had P. knowlesi infection, 24 (16%) had Plasmodium falciparum infection, and 21 (14%) had Plasmodium vivax. Patients with P. knowlesi infection presented with a nonspecific febrile illness, had a baseline median parasitemia value at hospital admission of 1387 parasites/μL (interquartile range, 6–222,570 parasites/μL), and all were thrombocytopenic at hospital admission or on the following day. Most (93.5%) of the patients with P. knowlesi infection had uncomplicated malaria that responded to chloroquine and primaquine treatment. Based on World Health Organization criteria for falciparum malaria, 7 patients with P. knowlesi infection (6.5%) had severe infections at hospital admission. The most frequent complication was respiratory distress, which was present at hospital admission in 4 patients and developed after admission in an additional 3 patients. P. knowlesi parasitemia at hospital admission was an independent determinant of respiratory distress, as were serum creatinine level, serum bilirubin, and platelet count at admission (P < .002 for each). Two patients with knowlesi malaria died, representing a case fatality rate of 1.8% (95% confidence interval, 0.2%–6.6%). Conclusions Knowlesi malaria causes a wide spectrum of disease. Most cases are uncomplicated and respond promptly to treatment, but approximately 1 in 10 patients develop potentially fatal complications. PMID

  8. Multiplicity of Infection and Disease Severity in Plasmodium vivax

    PubMed Central

    Pacheco, M. Andreína; Lopez-Perez, Mary; Vallejo, Andrés F.; Herrera, Sócrates; Arévalo-Herrera, Myriam; Escalante, Ananias A.

    2016-01-01

    Background Multiplicity of infection (MOI) refers to the average number of distinct parasite genotypes concurrently infecting a patient. Although several studies have reported on MOI and the frequency of multiclonal infections in Plasmodium falciparum, there is limited data on Plasmodium vivax. Here, MOI and the frequency of multiclonal infections were studied in areas from South America where P. vivax and P. falciparum can be compared. Methodology/Principal Findings As part of a passive surveillance study, 1,328 positive malaria patients were recruited between 2011 and 2013 in low transmission areas from Colombia. Of those, there were only 38 P. vivax and 24 P. falciparum clinically complicated cases scattered throughout the time of the study. Samples from uncomplicated cases were matched in time and location with the complicated cases in order to compare the circulating genotypes for these two categories. A total of 92 P. vivax and 57 P. falciparum uncomplicated cases were randomly subsampled. All samples were genotyped by using neutral microsatellites. Plasmodium vivax showed more multiclonal infections (47.7%) than P. falciparum (14.8%). Population genetics and haplotype network analyses did not detect differences in the circulating genotypes between complicated and uncomplicated cases in each parasite. However, a Fisher exact test yielded a significant association between having multiclonal P. vivax infections and complicated malaria. No association was found for P. falciparum infections. Conclusion The association between multiclonal infections and disease severity in P. vivax is consistent with previous observations made in rodent malaria. The contrasting pattern between P. vivax and P. falciparum could be explained, at least in part, by the fact that P. vivax infections have lineages that were more distantly related among them than in the case of the P. falciparum multiclonal infections. Future research should address the possible role that acquired

  9. Epidemiology and Control of Plasmodium vivax in Afghanistan

    PubMed Central

    Leslie, Toby; Nahzat, Sami; Sediqi, Walid

    2016-01-01

    Around half of the population of Afghanistan resides in areas at risk of malaria transmission. Two species of malaria (Plasmodium vivax and Plasmodium falciparum) account for a high burden of disease—in 2011, there were more than 300,000 confirmed cases. Around 80–95% of malaria is P. vivax. Transmission is seasonal and focal, below 2,000 m in altitude, and in irrigated areas which allow breeding of anopheline mosquito vectors. Malaria risk is stratified to improve targeting of interventions. Sixty-three of 400 districts account for ∼85% of cases, and are the target of more intense control efforts. Pressure on the disease is maintained through case management, surveillance, and use of long-lasting insecticide-treated nets. Plasmodium vivax treatment is hampered by the inability to safely treat latent hypnozoites with primaquine because G6PD deficiency affects up to 10% of males in some ethnic groups. The risk of vivax malaria recurrence (which may be as a result of reinfection or relapse) is around 30–45% in groups not treated with primaquine but 3–20% in those given 14-day or 8-week courses of primaquine. Greater access to G6PD testing and radical treatment would reduce the number of incident cases, reduce the infectious reservoir in the population, and has the potential to reduce transmission as a result. Alongside the lack of G6PD testing, under-resourcing and poor security hamper the control of malaria. Recent gains in reducing the burden of disease are fragile and at risk of reversal if pressure on the disease is not maintained. PMID:27708189

  10. Epidemiology and Control of Plasmodium vivax in Afghanistan.

    PubMed

    Leslie, Toby; Nahzat, Sami; Sediqi, Walid

    2016-12-28

    Around half of the population of Afghanistan resides in areas at risk of malaria transmission. Two species of malaria (Plasmodium vivax and Plasmodium falciparum) account for a high burden of disease-in 2011, there were more than 300,000 confirmed cases. Around 80-95% of malaria is P. vivax Transmission is seasonal and focal, below 2,000 m in altitude, and in irrigated areas which allow breeding of anopheline mosquito vectors. Malaria risk is stratified to improve targeting of interventions. Sixty-three of 400 districts account for ∼85% of cases, and are the target of more intense control efforts. Pressure on the disease is maintained through case management, surveillance, and use of long-lasting insecticide-treated nets. Plasmodium vivax treatment is hampered by the inability to safely treat latent hypnozoites with primaquine because G6PD deficiency affects up to 10% of males in some ethnic groups. The risk of vivax malaria recurrence (which may be as a result of reinfection or relapse) is around 30-45% in groups not treated with primaquine but 3-20% in those given 14-day or 8-week courses of primaquine. Greater access to G6PD testing and radical treatment would reduce the number of incident cases, reduce the infectious reservoir in the population, and has the potential to reduce transmission as a result. Alongside the lack of G6PD testing, under-resourcing and poor security hamper the control of malaria. Recent gains in reducing the burden of disease are fragile and at risk of reversal if pressure on the disease is not maintained. © The American Society of Tropical Medicine and Hygiene.

  11. Cell based assays for anti-Plasmodium activity evaluation.

    PubMed

    Mokgethi-Morule, Thabang; N'Da, David D

    2016-03-10

    Malaria remains one of the most common and deadly infectious diseases worldwide. The severity of this global public health challenge is reflected by the approximately 198 million people, who were reportedly infected in 2013 and by the more than 584,000 related deaths in that same year. The rising emergence of drug resistance towards the once effective artemisinin combination therapies (ACTs) has become a serious concern and warrants more robust drug development strategies, with the objective of eradicating malaria infections. The intricate biology and life cycle of Plasmodium parasites complicate the understanding of the disease in such a way that would enhance the development of more effective chemotherapies that would achieve radical clinical cure and that would prevent disease relapse. Phenotypic cell based assays have for long been a valuable approach and involve the screening and analysis of diverse compounds with regards to their activities towards whole Plasmodium parasites in vitro. To achieve the Millennium Development Goal (MDG) of malaria eradication by 2020, new generation drugs that are active against all parasite stages (erythrocytic (blood), exo-erythrocytic (liver stages and gametocytes)) are needed. Significant advances are being made in assay development to overcome some of the practical challenges of assessing drug efficacy, particularly in the liver and transmission stage Plasmodium models. This review discusses primary screening models and the fundamental progress being made in whole cell based efficacy screens of anti-malarial activity. Ongoing challenges and some opportunities for improvements in assay development that would assist in the discovery of effective, safe and affordable drugs for malaria treatments are also discussed.

  12. The Plasmodium sporozoite journey: a rite of passage.

    PubMed

    Kappe, Stefan H I; Kaiser, Karine; Matuschewski, Kai

    2003-03-01

    Sporozoites are the most versatile of the invasive stages of the Plasmodium life cycle. During their passage within the mosquito vector and the vertebrate host, sporozoites display diverse behaviors, including gliding locomotion and invasion of, migration through and egress from target cells. At the end of the journey, sporozoites invade hepatocytes and transform into exoerythrocytic stages, marking the transition from the pre-erythrocytic to the erythrocytic part of the life cycle. This article discusses recent work, mostly done with rodent malaria parasites, that has contributed to a better understanding of the sporozoites' complex biology and which has opened up new avenues for future sporozoite research.

  13. An extracellular inducer of asexual plasmodium formation in Physarum polycephalum.

    PubMed Central

    Youngman, P J; Adler, P N; Shinnick, T M; Holt, C E

    1977-01-01

    Asexual conversion of amoebae to plasmodia was studied in the Colonia isolate of the myxomycete, Physarum polycephalum. When a culture of Colonia amoebae is grown on a bacterial lawn, a period of amoebic growth precedes the appearance of cells committed to the plasmodial state. The onset of plasmodium production appears to be related to amoebic nutrition since cultures supplied with fewer bacteria display earlier differentiation. For a period of time after differentiation is initiated, conversion of amoebae to plasmodia is rapid and proceeds as an exponential function of time. A filter-transmissible substance, apparently released by differentiating cells, is implicated in the control of this rapid conversion. Images PMID:265558

  14. Experimental systems for studying Plasmodium/HIV coinfection.

    PubMed

    Frischknecht, Friedrich; Fackler, Oliver T

    2016-07-01

    Coinfections with Human Immunodeficiency Virus (HIV) and Plasmodium, the causative agents of AIDS and malaria, respectively, are frequent and their comorbidity especially in sub-Saharan Africa is high. While clinical studies suggest an influence of the two pathogens on the outcome of the respective infections, experimental studies on the molecular and immunological impact of coinfections are rare. This reflects the limited availability of suitable model systems that reproduce key properties of both pathologies. Here, we discuss key aspects of coinfection with a focus on currently established experimental systems, their limitations for coinfection studies and potential strategies for their improvement.

  15. Plasmodium vivax in Africa: hidden in plain sight?

    PubMed

    Rosenberg, Ronald

    2007-05-01

    People who live in tropical Africa, south of the Sahara, are predominantly negative for the Duffy blood-group antigen, which mediates invasion of reticulocytes by Plasmodium vivax. Recent reports of a parasite that was molecularly diagnosed as P. vivax from populations who are suspected, or known, to be Duffy negative confound a large body of evidence that states that invasion of P. vivax requires the Duffy antigen. If confirmed, one of several possible explanations is that P. vivax, which originated in Asia, is now evolving to exploit alternate invasion receptors in Africa.

  16. Chloroquine accumulation by purified plasma membranes from Plasmodium falciparum.

    PubMed

    Elandaloussi, Laurence M; Smith, Peter J

    2006-01-01

    Resistance of Plasmodium falciparum to chloroquine (CQ) has been associated with a decrease in CQ accumulation by parasitized erythrocytes. This study aimed at investigating the role of parasite plasma membranes (PPM) in the mechanism of CQ accumulation. CQ accumulation capabilities of membranes were determined using tritiated CQ. PPM isolated from chloroquine-sensitive parasites were found to accumulate less CQ than those isolated from chloroquine-resistant parasites. However, CQ accumulation was found to be ATP-independent suggesting that this accumulation results from binding rather than transport.

  17. Proteomics of the human malaria parasite Plasmodium falciparum.

    PubMed

    Sims, Paul F G; Hyde, John E

    2006-02-01

    The lethal species of malaria parasite, Plasmodium falciparum, continues to exact a huge toll of mortality and morbidity, particularly in sub-Saharan Africa. Completion of the genome sequence of this organism and advances in proteomics and mass spectrometry have opened up unprecedented opportunities for understanding the complex biology of this parasite and how it responds to drug challenge and other interventions. This review describes recent progress that has been made in applying proteomics technology to this important pathogen and provides a look forward to likely future developments.

  18. Three species of Plasmodium from Canada geese, Branta canadensis

    USGS Publications Warehouse

    Herman, C.M.; Barrow, J.H.

    1967-01-01

    Studies on Canada geese at the Seney National Wildlife Refuge in northern Michigan during the past few years have uncovered at least three species of Plasmodium: P circumflexum, P. relictum, and P. vaughani. Although rarely observed in direct blood smears from the wild hosts, isodiagnosis, using primarily domestic geese as recipients, revealed a prevalence of 60 percent in random samplings of the population. P. circumflexum is the most prevalent and mixed infections have been noted. In experimental infections, induced by blood inoculation, the malaria produced by P. circumflexum produces about a 70 percent mortality in Canada geese and about a 10 percent mortality in domestic geese.

  19. Major Histocompatibility Complex and Malaria: Focus on Plasmodium vivax Infection

    PubMed Central

    Lima-Junior, Josué da Costa; Pratt-Riccio, Lilian Rose

    2016-01-01

    The importance of host and parasite genetic factors in malaria resistance or susceptibility has been investigated since the middle of the last century. Nowadays, of all diseases that affect man, malaria still plays one of the highest levels of selective pressure on human genome. Susceptibility to malaria depends on exposure profile, epidemiological characteristics, and several components of the innate and adaptive immune system that influences the quality of the immune response generated during the Plasmodium lifecycle in the vertebrate host. But it is well known that the parasite’s enormous capacity of genetic variation in conjunction with the host genetics polymorphism is also associated with a wide spectrum of susceptibility degrees to complicated or severe forms of the disease. In this scenario, variations in genes of the major histocompatibility complex (MHC) associated with host resistance or susceptibility to malaria have been identified and used as markers in host–pathogen interaction studies, mainly those evaluating the impact on the immune response, acquisition of resistance, or increased susceptibility to infection or vulnerability to disease. However, due to the intense selective pressure, number of cases, and mortality rates, the majority of the reported associations reported concerned Plasmodium falciparum malaria. Studies on the MHC polymorphism and its association with Plasmodium vivax, which is the most widespread Plasmodium and the most prevalent species outside the African continent, are less frequent but equally important. Despite punctual contributions, there are accumulated evidences of human genetic control in P. vivax infection and disease. Herein, we review the current knowledge in the field of MHC and derived molecules (HLA Class I, Class II, TNF-α, LTA, BAT1, and CTL4) regarding P. vivax malaria. We discuss particularly the results of P. vivax studies on HLA class I and II polymorphisms in relation to host susceptibility, naturally

  20. The Plasmodium bottleneck: malaria parasite losses in the mosquito vector

    PubMed Central

    Smith, Ryan C; Vega-Rodríguez, Joel; Jacobs-Lorena, Marcelo

    2014-01-01

    Nearly one million people are killed every year by the malaria parasite Plasmodium. Although the disease-causing forms of the parasite exist only in the human blood, mosquitoes of the genus Anopheles are the obligate vector for transmission. Here, we review the parasite life cycle in the vector and highlight the human and mosquito contributions that limit malaria parasite development in the mosquito host. We address parasite killing in its mosquito host and bottlenecks in parasite numbers that might guide intervention strategies to prevent transmission. PMID:25185005

  1. An Autochthonous Case of Severe Plasmodium knowlesi Malaria in Thailand

    PubMed Central

    Nakaviroj, Surat; Kobasa, Teerayot; Teeranaipong, Phairote; Putaporntip, Chaturong; Jongwutiwes, Somchai

    2015-01-01

    A 58-year-old Thai man was infected with Plasmodium knowlesi in Chantaburi Province, eastern Thailand. In addition to pyrexia, the patient developed hypotension, renal failure, jaundice, and severe thrombocytopenia. The parasitemia at the time of admission was 16.67% or ∼503,400 parasites/μL. With artesunate treatment and supportive care, the patient recovered uneventfully. The occurrence of complicated knowlesi malaria in a low-endemic area underscores the risk of high morbidity from this simian malaria. PMID:25535314

  2. Diagnostic challenges and case management of the first imported case of Plasmodium knowlesi in Sri Lanka.

    PubMed

    Dewanee Ranaweera, A; Danansuriya, Manjula N; Pahalagedera, Kusumawathie; de A W Gunasekera, W M Kumudunayana T; Dharmawardena, Priyani; Mak, Keng Wai; Wong, Pei-Sze Jeslyn; Li, Mei-Zhi Irene; Tan, Cheong Huat; Hapuarachchi, Hapuarachchige C; Herath, Hema D B; Fernando, Deepika

    2017-03-21

    Sri Lanka has achieved 'malaria-free' status and is now in the phase of prevention of re-introduction of malaria. Imported malaria remains a challenge to resurgence of the disease. The diagnostic challenges encountered and the rapid response initiated to manage a Plasmodium infection, which was later confirmed as Plasmodium knowlesi, the first reported case from Sri Lanka, is discussed. An army officer who returned from Malaysia in October 2016 was found to be positive for Plasmodium both by microscopy and rapid diagnostic test (RDT) by the Anti Malaria Campaign Sri Lanka (AMC) during his third visit to a health care provider. Microscopy findings were suspicious of P. knowlesi infection as the smears showed parasite stages similar to both Plasmodium malariae and Plasmodium falciparum. Nested PCR at AMC confirmed Plasmodium genus, but not the species. In the absence of species confirmation, the patient was treated as a case of P. falciparum. The presence of P. knowlesi was later confirmed by a semi-nested PCR assay performed at the Environmental Health Institute, National Environmental Agency in Singapore. The parasite strain was also characterized by sequencing the circumsporozoite gene. Extensive case investigation including parasitological and entomological surveillance was carried out. Plasmodium knowlesi should be suspected in patients returning from countries in the South Asian region where the parasite is prevalent and when blood smear results are inconclusive.

  3. [Involvement of cyclic adenosine monophosphate in the control of motile behavior of Physarum polycephalum plasmodium].

    PubMed

    Matveeva, N B; Teplov, V A; Nezvetskiĭ, A R; Orlova, T G; Beĭlina, S I

    2012-01-01

    Possible involvement of autocrine factors into the control of motile behavior via a receptor-mediated mechanism was investigated in Physarum polycephalum plasmodium, a multinuclear amoeboid cell with the auto-oscillatory mode of motility. Cyclic adenosine monophosphate (cAMP) and extracellular cAMP-specific phosphodiesterase, its involvement into the control of plasmodium motile behavior was proved by action of its strong inhibitor, were regarded as putative autocrine factors. It was shown that the plasmodium secreted cAMP. When it was introduced into agar support, 0,1-1 mM cAMP induced a delay of the plasmodium spreading and its transition to migration. When locally applied, cAMP at the same concentrations induced typical for attractant action the increase in oscillation frequency and the decrease of ectoplasm elasticity. The ability to exhibit positive chemotaxis in cAMP gradient and the dependence of its realization were shown to depend on the plasmodium state. Chemotaxis test specimens obtained from the migrating plasmodium, unlike those obtained from growing culture, generate alternative fronts which compete effectively with fronts oriented towards the attractant increment. The results obtained support our supposition stated earlier that advance of the Physarum polycephalum plasmodium leading edge is determined by local extracellular cAMP gradients arising from a time delay between secretion and hydrolysis of the nucleotide.

  4. Plasmodium infection, anaemia and mosquito net use among school children across different settings in Kenya.

    PubMed

    Gitonga, Caroline W; Edwards, Tansy; Karanja, Peris N; Noor, Abdisalan M; Snow, Robert W; Brooker, Simon J

    2012-07-01

    To investigate risk factors, including reported net use, for Plasmodium infection and anaemia among school children and to explore variations in effects across different malaria ecologies occurring in Kenya. This study analysed data for 49 975 school children in 480 schools surveyed during a national school malaria survey, 2008-2010. Mixed effects logistic regression was used to investigate factors associated with Plasmodium infection and anaemia within different malaria transmission zones. Insecticide-treated net (ITN) use was associated with reduction in the odds of Plasmodium infection in coastal and western highlands epidemic zones and among boys in the lakeside high transmission zone. Other risk factors for Plasmodium infection and for anaemia also varied by zone. Plasmodium infection was negatively associated with increasing socio-economic status in all transmission settings, except in the semi-arid north-east zone. Plasmodium infection was a risk factor for anaemia in lakeside high transmission, western highlands epidemic and central low-risk zones, whereas ITN use was only associated with lower levels of anaemia in coastal and central zones and among boys in the lakeside high transmission zone. The risk factors for Plasmodium infection and anaemia, including the protective associations with ITN use, vary according to malaria transmission settings in Kenya, and future efforts to control malaria and anaemia should take into account such heterogeneities among school children. © 2012 Blackwell Publishing Ltd.

  5. Detection of avian Plasmodium spp. DNA sequences from mosquitoes captured in Minami Daito Island of Japan.

    PubMed

    Ejiri, Hiroko; Sato, Yukita; Sasaki, Emi; Sumiyama, Daisuke; Tsuda, Yoshio; Sawabe, Kyoko; Matsui, Shin; Horie, Sayaka; Akatani, Kana; Takagi, Masaoki; Omori, Sumie; Murata, Koichi; Yukawa, Masayoshi

    2008-11-01

    Several species of birds in Minami Daito Island, an oceanic island located in the far south from the main islands of Japan, were found to be infected with avian Plasmodium. However, no vector species of the avian malaria in this island have been revealed yet. To speculate potential vectors, we collected mosquitoes there and investigated using a PCR procedure whether the mosquitoes harbor avian malaria or not. Totally 1,264 mosquitoes including 9 species were collected during March 2006 to February 2007. The mosquitoes collected were stored every species, sampled date and location for DNA extraction. Fifteen out of 399 DNA samples showed positive for the partial mtDNA cytb gene of avian Plasmodium. Estimated minimum infection rate among collected mosquitoes was 1.2% in this study. Four species of mosquitoes; Aedes albopictus, Culex quinquefasciatus, Lutzia fuscanus and Mansonia sp. had avian Plasmodium gene sequences. Detected DNA sequences from A. albopictus and L. fuscanus were identical to an avian Plasmodium lineage detected in bull-headed shrike (Lanius bucephalus) captured in the island. Different sequences were detected from C. quinquefasciatus, which were corresponding to an avian Plasmodium from a sparrow (Passer montanus) and Plasmodium gallinaceum. Our results suggest that A. albopictus, Lutzia fuscanus, C. quinquefasciatus, and Mansonia sp. could be potential vectors of avian malaria in Minami Daito Island. This study was the first report of molecular detection of avian Plasmodium from mosquitoes in Japan.

  6. Effect of meteorological variables on Plasmodium vivax and Plasmodium falciparum malaria in outbreak prone districts of Rajasthan, India.

    PubMed

    Lingala, Mercy A L

    2017-03-09

    Malaria is a public health problem caused by Plasmodium parasite and transmitted by anopheline mosquitoes. Arid and semi-arid regions of western India are prone to malaria outbreaks. Malaria outbreak prone districts viz. Bikaner, Barmer and Jodhpur were selected to study the effect of meteorological variables on Plasmodium vivax and Plasmodium falciparum malaria outbreaks for the period of 2009-2012. The data of monthly malaria cases and meteorological variables was analysed using SPSS 20v. Spearman correlation analysis was conducted to examine the strength of the relationship between meteorological variables, P. vivax and P. falciparum malaria cases. Pearson's correlation analysis was carried out among the meteorological variables to observe the independent effect of each independent variable on the outcome. Results indicate that malaria outbreaks have occurred in Bikaner and Barmer due to continuous rains for more than two months. Rainfall has shown to be an important predictor of malaria outbreaks in Rajasthan. P. vivax is more significantly correlated with rainfall, minimum temperature (P<0.01) and less significantly with relative humidity (P<0.05); whereas P. falciparum is significantly correlated with rainfall, relative humidity (P<0.01) and less significantly with temperature (P<0.05). The determination of the lag period for P. vivax is relative humidity and for P. falciparum is temperature. The lag period between malaria cases and rainfall is shorter for P. vivax than P. falciparum. In conclusion, the knowledge generated is not only useful to take prompt malaria control interventions but also helpful to develop better forecasting model in outbreak prone regions. Copyright © 2017 The Author. Published by Elsevier Ltd.. All rights reserved.

  7. A morphology-based method for the diagnosis of red blood cells parasitized by Plasmodium malariae and Plasmodium ovale.

    PubMed

    Karimi, Alireza; Navidbakhsh, Mahdi; Haghi, Afsaneh Motevalli; Faghihi, Shahab

    2014-05-01

    The morphology of red blood cells (RBCs) is altered significantly during the maturation stages of malaria parasites, which include ring, trophozoite, and schizont. There is dissimilarity in terms of the morphological characteristics of parasitized RBCs infected by the 4 species of Plasmodium, including falciparum, vivax, malariae, and ovale. This makes the process of diagnosis very difficult, which may lead to a wrong treatment method and substantial damage to the health of the patient. An innovative technique in introduced that accurately defines the shape of parasitized RBCs at each stage of infection as a potential method of diagnosis. Giemsa-stained thin blood films were prepared using blood samples collected from healthy donors as well as patients infected with P. malariae and P. ovale. The diameter and thickness of healthy and infected RBCs at each stage of infection were measured from their optical images using Olysia and Scanning Probe Image Processor (SPIP) software, respectively. A shape equation was fitted based on the morphological characteristics of RBCs, and their relative 2-dimensional shapes were plotted using Wolfram Mathematica. At the ring stage, the thicknesses of RBCs parasitized by P. malariae (Pm-RBCs) and P. ovale (Po-RBCs) increased by 42% and 51%, respectively. Both Pm-RBCs and Po-RBCs remained nearly biconcave throughout parasite development even though their volumes increased. It is proposed that the morphology-based characterization technique introduced here could be used to intensify the accuracy of the Giemsa staining diagnosis method for the detection of the Plasmodium genus and infection stage. Based on the significant morphological alterations induced by different Plasmodium species, the results may also find practical use for faster prediction and treatment of human malaria.

  8. Submicroscopic and asymptomatic Plasmodium falciparum and Plasmodium vivax infections are common in western Thailand - molecular and serological evidence.

    PubMed

    Baum, Elisabeth; Sattabongkot, Jetsumon; Sirichaisinthop, Jeeraphat; Kiattibutr, Kirakorn; Davies, D Huw; Jain, Aarti; Lo, Eugenia; Lee, Ming-Chieh; Randall, Arlo Z; Molina, Douglas M; Liang, Xiaowu; Cui, Liwang; Felgner, Philip L; Yan, Guiyun

    2015-02-25

    Malaria is a public health problem in parts of Thailand, where Plasmodium falciparum and Plasmodium vivax are the main causes of infection. In the northwestern border province of Tak parasite prevalence is now estimated to be less than 1% by microscopy. Nonetheless, microscopy is insensitive at low-level parasitaemia. The objective of this study was to assess the current epidemiology of falciparum and vivax malaria in Tak using molecular methods to detect exposure to and infection with parasites; in particular, the prevalence of asymptomatic infections and infections with submicroscopic parasite levels. Three-hundred microlitres of whole blood from finger-prick were collected into capillary tubes from residents of a sentinel village and from patients at a malaria clinic. Pelleted cellular fractions were screened by quantitative PCR to determine parasite prevalence, while plasma was probed on a protein microarray displaying hundreds of P. falciparum and P. vivax proteins to obtain antibody response profiles in those individuals. Of 219 samples from the village, qPCR detected 25 (11.4%) Plasmodium sp. infections, of which 92% were asymptomatic and 100% were submicroscopic. Of 61 samples from the clinic patients, 27 (44.3%) were positive by qPCR, of which 25.9% had submicroscopic parasite levels. Cryptic mixed infections, misdiagnosed as single-species infections by microscopy, were found in 7 (25.9%) malaria patients. All sample donors, parasitaemic and non-parasitaemic alike, had serological evidence of parasite exposure, with 100% seropositivity to at least 54 antigens. Antigens significantly associated with asymptomatic infections were P. falciparum MSP2, DnaJ protein, putative E1E2 ATPase, and three others. These findings suggest that parasite prevalence is higher than currently estimated by local authorities based on the standard light microscopy. As transmission levels drop in Thailand, it may be necessary to employ higher throughput and sensitivity methods for

  9. New potential Plasmodium brasilianum hosts: tamarin and marmoset monkeys (family Callitrichidae).

    PubMed

    Alvarenga, Denise A M; Pina-Costa, Anielle; Bianco, Cesare; Moreira, Silvia B; Brasil, Patricia; Pissinatti, Alcides; Daniel-Ribeiro, Claudio T; Brito, Cristiana F A

    2017-02-10

    Non-human primates (NHPs) as a source for Plasmodium infections in humans are a challenge for malaria elimination. In Brazil, two species of Plasmodium have been described infecting NHPs, Plasmodium brasilianum and Plasmodium simium. Both species are infective to man. Plasmodium brasilianum resembles morphologically, genetically and immunologically the human quartan Plasmodium malariae. Plasmodium brasilianum naturally infects species of non-human primates from all New World monkey families from a large geographic area. In the family Callitrichidae only the genus Saguinus has been described infected so far. The present study describes the natural infection of P. brasilianum in tamarins and marmosets of the genera Callithrix, Mico and Leontopithecus in the Atlantic forest. One hundred and twenty-two NHPs of the family Callitrichidae housed in the Primate Centre of Rio de Janeiro (CPRJ) were sampled in June 2015, and January and July 2016. The CPRJ is located in the Atlantic forest in the Guapimirim municipality, in the Rio de Janeiro state, where human autochthonous cases of malaria have been reported. The samples were screened for the presence of Plasmodium using optical microscopy and nested PCR for detection of 18S small subunit rRNA gene. The amplicon was sequenced to confirm the molecular diagnosis. The frequency of Plasmodium infections detected by nested PCR in New World monkeys of the family Callitrichidae was 6.6%. For the first time, Callitrichidae primates of genera Callithrix, Mico and Leontopithecus were found naturally infected with P. brasilianum. Infection was confirmed by sequencing a small fragment of 18S rRNA gene, although no parasites were detected in blood smears. The reported P. brasilianum infection in NHP species maintained in captivity suggests that infection can be favoured by the presence of vectors and the proximity between known (and unknown) hosts of malaria. Thus, the list of potential malaria reservoirs needs to be further explored.

  10. Nek5 promotes centrosome integrity in interphase and loss of centrosome cohesion in mitosis

    PubMed Central

    Sahota, Navdeep K.; Pelletier, Laurence; Morrison, Ciaran G.

    2015-01-01

    Nek5 is a poorly characterized member of the NIMA-related kinase family, other members of which play roles in cell cycle progression and primary cilia function. Here, we show that Nek5, similar to Nek2, localizes to the proximal ends of centrioles. Depletion of Nek5 or overexpression of kinase-inactive Nek5 caused unscheduled separation of centrosomes in interphase, a phenotype also observed upon overexpression of active Nek2. However, separated centrosomes that resulted from Nek5 depletion remained relatively close together, exhibited excess recruitment of the centrosome linker protein rootletin, and had reduced levels of Nek2. In addition, Nek5 depletion led to loss of PCM components, including γ-tubulin, pericentrin, and Cdk5Rap2, with centrosomes exhibiting reduced microtubule nucleation. Upon mitotic entry, Nek5-depleted cells inappropriately retained centrosome linker components and exhibited delayed centrosome separation and defective chromosome segregation. Hence, Nek5 is required for the loss of centrosome linker proteins and enhanced microtubule nucleation that lead to timely centrosome separation and bipolar spindle formation in mitosis. PMID:25963817

  11. Identification and localization of a Novel Invasin of Plasmodium falciparum.

    PubMed

    Hans, Nidhi; Relan, Udbhav; Dubey, Nneha; Gaur, Deepak; Chauhan, V S

    2015-08-01

    Plasmodium falciparum is the causative organism for the most severe form of malaria among humans. The clinical symptoms are accredited to the asexual stage of parasite life cycle, involving merozoite invasion of erythrocyte, development and re-invasion into the new erythrocyte. Interaction of parasite proteins present on the surface or secreted from apical organelles with the host receptors is indispensable for the invasion process. Identification and elucidation of precise localization and function of these proteins will not only enhance our understanding of this process but will also aid in the progress of development of treatment strategies against malaria. Here we report the identification and localization of a novel protein, PfAEP (P. falciparum Apical Exonemal Protein) (PF3D7_1137200/ PF11_0383) which is conserved across Plasmodium species. Transcription and translation analysis have confirmed its expression in the schizont stage of P. falciparum. Super-resolution microscopy in schizonts and merozoites revealed its localization in the exonemes of P. falciparum.

  12. Chemotherapeutic strategies for reducing transmission of Plasmodium vivax malaria.

    PubMed

    Douglas, Nicholas M; John, George K; von Seidlein, Lorenz; Anstey, Nicholas M; Price, Ric N

    2012-01-01

    Effective use of anti-malarial drugs is key to reducing the transmission potential of Plasmodium vivax. In patients presenting with symptomatic disease, treatment with potent and relatively slowly eliminated blood schizontocidal regimens administered concurrently with a supervised course of 7 mg/kg primaquine over 7-14 days has potential to exert the greatest transmission-blocking benefit. Given the spread of chloroquine-resistant P. vivax strains, the artemisinin combination therapies dihydroartemisinin + piperaquine and artesunate + mefloquine are currently the most assured means of preventing P. vivax recrudescence. Preliminary evidence suggests that, like chloroquine, these combinations potentiate the hypnozoitocidal effect of primaquine, but further supportive evidence is required. In view of the high rate of P. vivax relapse following falciparum infections in co-endemic regions, there is a strong argument for broadening current radical cure policy to include the administration of hypnozoitocidal doses of primaquine to patients with Plasmodium falciparum malaria. The most important reservoir for P. vivax transmission is likely to be very low-density, asymptomatic infections, the majority of which will arise from liver-stage relapses. Therefore, judicious mass administration of hypnozoitocidal therapy will reduce transmission of P. vivax to a greater extent than strategies focused on treatment of symptomatic patients. An efficacious hypnozoitocidal agent with a short curative treatment course would be particularly useful in mass drug administration campaigns.

  13. Carotenoid Biosynthesis in Intraerythrocytic Stages of Plasmodium falciparum*S⃞

    PubMed Central

    Tonhosolo, Renata; D'Alexandri, Fabio L.; de Rosso, Veridiana V.; Gazarini, Marcos L.; Matsumura, Miriam Y.; Peres, Valnice J.; Merino, Emilio F.; Carlton, Jane M.; Wunderlich, Gerhard; Mercadante, Adriana Z.; Kimura, Emília A.; Katzin, Alejandro M.

    2009-01-01

    Carotenoids are widespread lipophilic pigments synthesized by all photosynthetic organisms and some nonphotosynthetic fungi and bacteria. All carotenoids are derived from the C40 isoprenoid precursor geranylgeranyl pyrophosphate, and their chemical and physical properties are associated with light absorption, free radical scavenging, and antioxidant activity. Carotenoids are generally synthesized in well defined subcellular organelles, the plastids, which are also present in the phylum Apicomplexa, which comprises a number of important human parasites, such as Plasmodium and Toxoplasma. Recently, it was demonstrated that Toxoplasma gondii synthesizes abscisic acid. We therefore asked if Plasmodium falciparum is also capable of synthesizing carotenoids. Herein, biochemical findings demonstrated the presence of carotenoid biosynthesis in the intraerythrocytic stages of the apicomplexan parasite P. falciparum. Using metabolic labeling with radioisotopes, in vitro inhibition tests with norflurazon, a specific inhibitor of plant carotenoid biosynthesis, the results showed that intraerythrocytic stages of P. falciparum synthesize carotenoid compounds. A plasmodial enzyme that presented phytoene synthase activity was also identified and characterized. These findings not only contribute to the current understanding of P. falciparum evolution but shed light on a pathway that could serve as a chemotherapeutic target. PMID:19203994

  14. Structural basis for chirality and directional motility of Plasmodium sporozoites

    PubMed Central

    Kudryashev, Mikhail; Münter, Sylvia; Lemgruber, Leandro; Montagna, Georgina; Stahlberg, Henning; Matuschewski, Kai; Meissner, Markus; Cyrklaff, Marek; Frischknecht, Friedrich

    2014-01-01

    Summary Plasmodium sporozoites can move at high speed for several tens of minutes, which is essential for the initial stage of a malaria infection. The crescent-shaped sporozoites move on 2D substrates preferably in the same direction on circular paths giving raise to helical paths in 3D matrices. Here we determined the structural basis that underlies this type of movement. Immature, non-motile sporozoites were found to lack the subpellicular network required for obtaining the crescent parasite shape. In vitro, parasites moving in the favoured direction move faster and more persistent than the few parasites that move in the opposite direction. Photobleaching experiments showed that sporozoites flip their ventral side up when switching the direction of migration. Cryo-electron tomography revealed a polarized arrangement of microtubules and polar rings towards the substrate in Plasmodium sporozoites, but not in the related parasite Toxoplasma gondii. As a consequence, secretory vesicles, which release proteins involved in adhesion, migration and invasion at the front end of the parasite, are delivered towards the substrate. The resulting chiral structure of the parasite appears to determine the unique directionality of movement and could explain how the sporozoite achieves rapid and sustained directional motility in the absence of external stimuli. PMID:22776715

  15. Malaria vaccines: identifying Plasmodium falciparum liver-stage targets

    PubMed Central

    Longley, Rhea J.; Hill, Adrian V. S.; Spencer, Alexandra J.

    2015-01-01

    The development of a highly efficacious and durable vaccine for malaria remains a top priority for global health researchers. Despite the huge rise in recognition of malaria as a global health problem and the concurrent rise in funding over the past 10–15 years, malaria continues to remain a widespread burden. The evidence of increasing resistance to anti-malarial drugs and insecticides is a growing concern. Hence, an efficacious and durable preventative vaccine for malaria is urgently needed. Vaccines are one of the most cost-effective tools and have successfully been used in the prevention and control of many diseases, however, the development of a vaccine for the Plasmodium parasite has proved difficult. Given the early success of whole sporozoite mosquito-bite delivered vaccination strategies, we know that a vaccine for malaria is an achievable goal, with sub-unit vaccines holding great promise as they are simple and cheap to both manufacture and deploy. However a major difficulty in development of sub-unit vaccines lies within choosing the appropriate antigenic target from the 5000 or so genes expressed by the parasite. Given the liver-stage of malaria represents a bottle-neck in the parasite’s life cycle, there is widespread agreement that a multi-component sub-unit malaria vaccine should preferably contain a liver-stage target. In this article we review progress in identifying and screening Plasmodium falciparum liver-stage targets for use in a malaria vaccine. PMID:26441899

  16. Gene copy number variation throughout the Plasmodium falciparum genome.

    PubMed

    Cheeseman, Ian H; Gomez-Escobar, Natalia; Carret, Celine K; Ivens, Alasdair; Stewart, Lindsay B; Tetteh, Kevin K A; Conway, David J

    2009-08-04

    Gene copy number variation (CNV) is responsible for several important phenotypes of the malaria parasite Plasmodium falciparum, including drug resistance, loss of infected erythrocyte cytoadherence and alteration of receptor usage for erythrocyte invasion. Despite the known effects of CNV, little is known about its extent throughout the genome. We performed a whole-genome survey of CNV genes in P. falciparum using comparative genome hybridisation of a diverse set of 16 laboratory culture-adapted isolates to a custom designed high density Affymetrix GeneChip array. Overall, 186 genes showed hybridisation signals consistent with deletion or amplification in one or more isolate. There is a strong association of CNV with gene length, genomic location, and low orthology to genes in other Plasmodium species. Sub-telomeric regions of all chromosomes are strongly associated with CNV genes independent from members of previously described multigene families. However, approximately 40% of CNV genes were located in more central regions of the chromosomes. Among the previously undescribed CNV genes, several that are of potential phenotypic relevance are identified. CNV represents a major form of genetic variation within the P. falciparum genome; the distribution of gene features indicates the involvement of highly non-random mutational and selective processes. Additional studies should be directed at examining CNV in natural parasite populations to extend conclusions to clinical settings.

  17. Late relapse of imported Plasmodium ovale malaria: a case report.

    PubMed

    Siala, Emna; Gastli, Mondher; Essid, Rym; Jemal, Sana; Ben Abdallah, Rym; Ben Abda, Imène; Aoun, Karim; Bouratbine, Aida

    2015-06-01

    We report the first case of an imported Plasmodium ovale relapse in a Tunisian man who developed malaria three years after leaving sub- Saharan Africa. A 29-year-old Tunisian man consulted in September 2011 because of a fever, myalgia, and headache that had begun eight days earlier and persisted despite treatment with oral antibiotics. On questioning, the patient stated that he had resided three years ago for six months in Ivory Coast, where he acquired malaria. He was treated with artemether-lumefantrine. The patient said he had no recent travel to any other malaria-endemic area and had not received a blood transfusion. A first microscopy of peripheral blood smears was negative for malaria parasites. The diagnosis was established 17 days after onset of symptoms. A repeat microscopic examination of blood smears confirmed the presence of Plasmodium ovale with a parasitemia lower than 0.1%. The patient was treated with artemether lumefantrine, followed by primaquine. This case emphasizes the possibility of relapse of some plasmodial species. It highlights the importance of repeating microscopic examination of blood when the diagnosis of malaria is suspected.

  18. Genetic diversity of Plasmodium vivax isolates from Azerbaijan

    PubMed Central

    Leclerc, Marie Claude; Menegon, Michela; Cligny, Alexandra; Noyer, Jean Louis; Mammadov, Suleyman; Aliyev, Namig; Gasimov, Elkhan; Majori, Giancarlo; Severini, Carlo

    2004-01-01

    Background Plasmodium vivax, although causing a less serious disease than Plasmodium falciparum, is the most widespread of the four human malarial species. Further to the recent recrudescence of P. vivax cases in the Newly Independent States (NIS) of central Asia, a survey on the genetic diversity and dissemination in Azerbaijan was undertaken. Azerbaijan is at the crossroads of Asia and, as such, could see a rise in the number of cases, although an effective malaria control programme has been established in the country. Methods Thirty-six P. vivax isolates from Central Azerbaijan were characterized by analysing the genetic polymorphism of the circumsporozoite protein (CSP) and the merozoite surface protein 1 (MSP-1) genes, using PCR amplifications and amplicons sequencing. Results Analysis of CSP sequences showed that all the processed isolates belong to the VK 210 type, with variations in the alternation of alanine residue (A) or aspartic acid residue (D) in the repeat motif GDRA(A/D)GQPA along the sequence. As far as MSP-1 genotyping is concerned, it was found that the majority of isolates analysed belong to Belem and Sal I types. Five recombinant isolates were also identified. Combined analysis with the two genetic markers allowed the identification of 19 plasmodial sub-types. Conclusion The results obtained in the present study indicate that there are several P. vivax clones circulating in Azerbaijan and, consequently, a careful malaria surveillance could be of paramount importance to identify, at early stage, the occurrence of possible P. vivax malaria outbreaks. PMID:15535878

  19. Low-Complexity Regions in Plasmodium falciparum Proteins

    PubMed Central

    Pizzi, Elisabetta; Frontali, Clara

    2001-01-01

    Full-sequence data available for Plasmodium falciparum chromosomes 2 and 3 are exploited to perform a statistical analysis of the long tracts of biased amino acid composition that characterize the vast majority of P. falciparum proteins and to make a comparison with similarly defined tracts from other simple eukaryotes. When the relatively minor subset of prevalently hydrophobic segments is discarded from the set of low-complexity segments identified by current segmentation methods in P. falciparum proteins, a good correspondence is found between prevalently hydrophilic low-complexity segments and the species-specific, rapidly diverging insertions detected by multiple-alignment procedures when sequences of bona fide homologs are available. Amino acid preferences are fairly uniform in the set of hydrophilic low-complexity segments identified in the two P. falciparum chromosomes sequenced, as well as in sequenced genes from Plasmodium berghei, but differ from those observed in Saccharomyces cerevisiae and Dictyostelium discoideum. In the two plasmodial species, amino acid frequencies do not correlate with properties such as hydrophilicity, small volume, or flexibility, which might be expected to characterize residues involved in nonglobular domains but do correlate with A-richness in codons. An effect of phenotypic selection versus neutral drift, however, is suggested by the predominance of asparagine over lysine. PMID:11157785

  20. Platform for Plasmodium vivax vaccine discovery and development.

    PubMed

    Valencia, Sócrates Herrera; Rodríguez, Diana Carolina; Acero, Diana Lucía; Ocampo, Vanessa; Arévalo-Herrera, Myriam

    2011-08-01

    Plasmodium vivax is the most prevalent malaria parasite on the American continent. It generates a global burden of 80-100 million cases annually and represents a tremendous public health problem, particularly in the American and Asian continents. A malaria vaccine would be considered the most cost-effective measure against this vector-borne disease and it would contribute to a reduction in malaria cases and to eventual eradication. Although significant progress has been achieved in the search for Plasmodium falciparum antigens that could be used in a vaccine, limited progress has been made in the search for P. vivax components that might be eligible for vaccine development. This is primarily due to the lack of in vitro cultures to serve as an antigen source and to inadequate funding. While the most advanced P. falciparum vaccine candidate is currently being tested in Phase III trials in Africa, the most advanced P. vivax candidates have only advanced to Phase I trials. Herein, we describe the overall strategy and progress in P. vivax vaccine research, from antigen discovery to preclinical and clinical development and we discuss the regional potential of Latin America to develop a comprehensive platform for vaccine development.

  1. Plasmodium activates the innate immune response of Anopheles gambiae mosquitoes.

    PubMed Central

    Richman, A M; Dimopoulos, G; Seeley, D; Kafatos, F C

    1997-01-01

    Innate immune-related gene expression in the major disease vector mosquito Anopheles gambiae has been analyzed following infection by the malaria parasite, Plasmodium berghei. Substantially increased levels of mRNAs encoding the antibacterial peptide defensin and a putative Gram-negative bacteria-binding protein (GNBP) are observed 20-30 h after ingestion of an infected blood-meal, at a time which indicates that this induction is a response to parasite invasion of the midgut epithelium. The induction is dependent upon the ingestion of infective, sexual-stage parasites, and is not due to opportunistic co-penetration of resident gut micro-organisms into the hemocoel. The response is activated following infection both locally (in the midgut) and systemically (in remaining tissues, presumably fat body and/or hemocytes). The observation that Plasmodium can trigger a molecularly defined immune response in the vector constitutes an important advance in our understanding of parasite-vector interactions that are potentially involved in malaria transmission, and extends knowledge of the innate immune system of insects to encompass responses to protozoan parasites. PMID:9321391

  2. Platform for Plasmodium vivax vaccine discovery and development

    PubMed Central

    Valencia/, Sócrates Herrera; Rodríguez, Diana Carolina; Acero, Diana Lucía; Ocampo, Vanessa; Arévalo-Herrera, Myriam

    2016-01-01

    Plasmodium vivax is the most prevalent malaria parasite on the American continent. It generates a global burden of 80–100 million cases annually and represents a tremendous public health problem, particularly in the American and Asian continents. A malaria vaccine would be considered the most cost-effective measure against this vector-borne disease and it would contribute to a reduction in malaria cases and to eventual eradication. Although significant progress has been achieved in the search for Plasmodium falciparum antigens that could be used in a vaccine, limited progress has been made in the search for P. vivax components that might be eligible for vaccine development. This is primarily due to the lack of in vitro cultures to serve as an antigen source and to inadequate funding. While the most advanced P. falciparum vaccine candidate is currently being tested in Phase III trials in Africa, the most advanced P. vivax candidates have only advanced to Phase I trials. Herein, we describe the overall strategy and progress in P. vivax vaccine research, from antigen discovery to preclinical and clinical development and we discuss the regional potential of Latin America to develop a comprehensive platform for vaccine development. PMID:21881773

  3. Cloning and characterization of Plasmodium vivax thioredoxin peroxidase-1.

    PubMed

    Hakimi, Hassan; Asada, Masahito; Angeles, Jose Ma M; Inoue, Noboru; Kawazu, Shin-Ichiro

    2012-08-01

    Reactive oxygen species produced from hemoglobin digestion and the host immune system could have adverse effects on malaria parasites. To protect themselves, malaria parasites are highly dependent on the antioxidant enzymes, including superoxide dismutases and thioredoxin-dependent peroxidases. To date, several thioredoxin peroxidases (TPx) have been characterized in Plasmodium falciparum, but the TPx in Plasmodium vivax has not yet been characterized. The complete sequence of gene coding for thioredoxin peroxidase-1 of P. vivax (PvTPx-1) was amplified by PCR and cloned. Using the recombinant PvTPx-1 (rPvTPx-1), polyclonal antibody was produced in mice for immunolocalization of the enzyme in the parasite. The antioxidant activity of rPvTPx-1 was evaluated by mixed-function oxidation assay. PvTPx-1 has two conserved cysteine residues in the amino acid sequence at the positions 50 and 170 which formed a dimer under a non-reducing condition. Using a thiol mixed-function oxidation assay, the antioxidant activity of rPvTPx-1 was revealed. Indirect immunofluorescence microscopy with the specific antibody indicated that PvTPx-1 was expressed in the cytoplasm of the erythrocytic stage of the parasite in a dots-like pattern. The results suggest that P. vivax uses TPx-1 to reduce and detoxify hydrogen peroxides in order to maintain their redox homeostasis and proliferation in the host body.

  4. Unusual presentation of Plasmodium vivax: a neglected human malaria parasite.

    PubMed

    Kute, Vivek B; Goswami, Jitendra G; Vanikar, Aruna V; Shah, Pankaj R; Gumber, Manoj R; Patel, Himanshu V; Kanodia, Kamal V; Trivedi, Hargovind L

    2012-06-01

    Severe and complicated malaria is usually caused by Plasmodium falciparum malaria (PF) but it has been increasingly observed that Plasmodium vivax malaria (PV), which was otherwise considered to be benign malaria, with a low case-fatality ratio, can also occasionally result in severe disease as with PF malaria. There is an urgent need to re-examine the clinical spectrum and burden of PV so that adequate control measures can be implemented against this emerging but neglected disease. We report a case of severe PV malaria with multi-organ dysfunction. Patients exhibited acute kidney injury, severe anemia/thrombocytopenia, jaundice, hypoglycemia, hyponatremia, and pulmonary edema. Peripheral blood microscopy by trained and expert pathologist and rapid diagnostic test showed the presence of PV and absence of PF. The patient recovered completely with anti-malarial drugs, supportive measures, and hemodialysis.Recent microrheologic research that analyzed malaria severity in PV clearly demonstrated enhanced aggregation, erythrocyte clumping, and reduced deformability affecting microcirculation. Our case report highlights the fact that PV malaria is benign by name but not always by nature. PV can lead to unusual and potentially life-threatening complications. Further large-scale multi-centric studies are needed to define this less known entity.

  5. [Acute renal failure and Plasmodium falciparum malaria: a case report].

    PubMed

    Kissou, S A; Cessouma, R; Barro, M; Traoré, H; Nacro, B

    2012-01-01

    Malaria is an endemic disease caused by one of the several Plasmodium species. Severe malaria is mainly due to Plasmodium falciparum in highly endemic areas. Acute renal failure (ARF) is a criterion of malaria severity as defined by WHO. Often observed in adults, particularly in India and Southeast Asia, this complication remains a rare complication of malaria in children. We report a case of oliguric ARF that occurred in a 7-year-old girl a few days after the onset of fever. The vascular obstruction by parasitized erythrocytes often causing tubular necrosis is the primary mechanism of renal failure. As a possible diagnosis, hemolytic uremic syndrome, renal failure and quartan hemoglobinuric nephropathy are other possible causes of renal failure in malaria. Renal biopsy, which was not performed in our patient, would have been a great help, but was not available. The outcome was favorable with recovery of renal function after 3 weeks of diuretic therapy. This development is not always the rule and the prognosis depends on early diagnosis and treatment options.

  6. Plasmodium vivax: clinical spectrum, risk factors and pathogenesis.

    PubMed

    Anstey, Nicholas M; Douglas, Nicholas M; Poespoprodjo, Jeanne R; Price, Ric N

    2012-01-01

    Vivax malaria was historically described as 'benign tertian malaria' because individual clinical episodes were less likely to cause severe illness than Plasmodium falciparum. Despite this, Plasmodium vivax was, and remains, responsible for major morbidity and significant mortality in vivax-endemic areas. Single infections causing febrile illness in otherwise healthy individuals rarely progress to severe disease. Nevertheless, in the presence of co-morbidities, P. vivax can cause severe illness and fatal outcomes. Recurrent or chronic infections in endemic areas can cause severe anaemia and malnutrition, particularly in early childhood. Other severe manifestations include acute lung injury, acute kidney injury and uncommonly, coma. Multiorgan failure and shock are described but further studies are needed to investigate the role of bacterial and other co-infections in these syndromes. In pregnancy, P. vivax infection can cause maternal anaemia, miscarriage, low birth weight and congenital malaria. Compared to P. falciparum, P. vivax has a greater capacity to elicit an inflammatory response, resulting in a lower pyrogenic threshold. Conversely, cytoadherence of P. vivax to endothelial cells is less frequent and parasite sequestration is not thought to be a significant cause of severe illness in vivax malaria. With a predilection for young red cells, P. vivax does not result in the high parasite biomass associated with severe disease in P. falciparum, but a four to fivefold greater removal of uninfected red cells from the circulation relative to P. falciparum is associated with a similar risk of severe anaemia. Mechanisms underlying the pathogenesis of severe vivax syndromes remain incompletely understood.

  7. Targeting molecular interactions essential for Plasmodium sexual reproduction

    PubMed Central

    Vega-Rodriguez, Joel; Perez-Barreto, Davinia; Ruiz-Reyes, Antonio; Jacobs-Lorena, Marcelo

    2015-01-01

    Summary Malaria remains one of the most devastating infectious diseases, killing up to a million people every year. Whereas much progress has been made in understanding the life cycle of the parasite in the human host and in the mosquito vector, significant gaps of knowledge remain. Fertilization of malaria parasites, a process that takes place in the lumen of the mosquito midgut, is poorly understood and the molecular interactions (receptor–ligand) required for Plasmodium fertilization remain elusive. By use of a phage display library, we identified FG1 (Female Gamete peptide 1), a peptide that binds specifically to the surface of female Plasmodium berghei gametes. Importantly, FG1 but not a scrambled version of the peptide, strongly reduces P. berghei oocyst formation by interfering with fertilization. In addition, FG1 also inhibits P. falciparum oocyst formation suggesting that the peptide binds to a molecule on the surface of the female gamete whose structure is conserved. Identification of the molecular interactions disrupted by the FG1 peptide may lead to the development of novel malaria transmission-blocking strategies. PMID:25944054

  8. Quinolone-based drugs against Toxoplasma gondii and Plasmodium spp.

    PubMed

    Anquetin, Guillaume; Greiner, Jacques; Vierling, Pierre

    2005-09-01

    Owing to the rapid emergence of multi-resistant strains of Plasmodium spp. (the causative agents of malaria) and the limitations of drugs used against Toxoplasma gondii (an important opportunistic pathogen associated with AIDS and congenital birth defects), the discovery of new therapeutical targets and the development of new drugs are needed. The presence of the prokaryotic-like organelle in apicomplexan parasites (i.e. plastids), which comprise these major human pathogens, may represent a unique target for antibiotics against these protozoa. Quinolones which are known to be highly potent against bacteria were also found to specifically disrupt these parasites. They inhibit DNA replication by interacting with two essential bacterial type II topoisomerases, DNA gyrase and topoisomerase IV. There are some clues that quinolones act on plastids with a similar mechanism of action. After a brief presentation of plasmodium and toxoplasma dedicated to their life cycle, the chemotherapies presently used in clinics to fight against these protozoa and the potential new targets and drugs, we will focus our attention on their plastid which is one of these promising new targets. Then, we will present the various drugs and generations of quinolones, the leading molecules, and their inhibitory effects against these parasites together with their pharmacological properties that have been established from in vitro and in vivo studies. We will also discuss their possible mode of action.

  9. Inhibition of a Plasmodium vinckei cysteine proteinase cures murine malaria.

    PubMed Central

    Rosenthal, P J; Lee, G K; Smith, R E

    1993-01-01

    Intraerythrocytic malaria parasites degrade hemoglobin as a principal source of amino acids for parasite protein synthesis. We have previously identified a Plasmodium falciparum trophozoite cysteine proteinase as a putative hemoglobinase and shown that specific inhibitors of this proteinase block the hydrolysis of globin and the development of cultured parasites. We now show that the murine malaria parasite Plasmodium vinckei has an analogous cysteine proteinase with similar biochemical properties to the P. falciparum proteinase, including an acid pH optimum, a preference for the peptide proteolytic substrate benzyloxycarbonyl (Z)-Phe-Arg-7-amino-4-methylcoumarin, and nonomolar inhibition by seven peptide fluoromethyl ketone proteinase inhibitors. Thus, P. vinckei offers a model system for the in vivo testing of the antimalarial properties of cysteine proteinase inhibitors. One of the proteinase inhibitors studied, morpholine urea (Mu)-Phe-Homophenylalanine (HPhe)-CH2F strongly inhibited the P. vinckei cysteine proteinase in vitro and rapidly blocked parasite cysteine proteinase activity in vivo. When administered four times a day for 4 d to P. vinckei-infected mice, Mu-Phe-HPhe-CH2F elicited long-term cures in 80% of the treated animals. These results show that peptide proteinase inhibitors can be effective antimalarial compounds in vivo and suggest that the P. falciparum cysteine proteinase is a promising target for chemotherapy. Images PMID:8450035

  10. Epigenetic Silencing of Plasmodium falciparum Genes Linked to Erythrocyte Invasion

    PubMed Central

    Cortés, Alfred; Carret, Celine; Kaneko, Osamu; Yim Lim, Brian Y. S.; Ivens, Alasdair; Holder, Anthony A

    2007-01-01

    The process of erythrocyte invasion by merozoites of Plasmodium falciparum involves multiple steps, including the formation of a moving junction between parasite and host cell, and it is characterised by the redundancy of many of the receptor–ligand interactions involved. Several parasite proteins that interact with erythrocyte receptors or participate in other steps of invasion are encoded by small subtelomerically located gene families of four to seven members. We report here that members of the eba, rhoph1/clag, acbp, and pfRh multigene families exist in either an active or a silenced state. In the case of two members of the rhoph1/clag family, clag3.1 and clag3.2, expression was mutually exclusive. Silencing was clonally transmitted and occurred in the absence of detectable DNA alterations, suggesting that it is epigenetic. This was demonstrated for eba-140. Our data demonstrate that variant or mutually exclusive expression and epigenetic silencing in Plasmodium are not unique to genes such as var, which encode proteins that are exported to the surface of the erythrocyte, but also occur for genes involved in host cell invasion. Clonal variant expression of invasion-related ligands increases the flexibility of the parasite to adapt to its human host. PMID:17676953

  11. Preerythrocytic, live-attenuated Plasmodium falciparum vaccine candidates by design.

    PubMed

    VanBuskirk, Kelley M; O'Neill, Matthew T; De La Vega, Patricia; Maier, Alexander G; Krzych, Urszula; Williams, Jack; Dowler, Megan G; Sacci, John B; Kangwanrangsan, Niwat; Tsuboi, Takafumi; Kneteman, Norman M; Heppner, Donald G; Murdock, Brant A; Mikolajczak, Sebastian A; Aly, Ahmed S I; Cowman, Alan F; Kappe, Stefan H I

    2009-08-04

    Falciparum malaria is initiated when Anopheles mosquitoes transmit the Plasmodium sporozoite stage during a blood meal. Irradiated sporozoites confer sterile protection against subsequent malaria infection in animal models and humans. This level of protection is unmatched by current recombinant malaria vaccines. However, the live-attenuated vaccine approach faces formidable obstacles, including development of accurate, reproducible attenuation techniques. We tested whether Plasmodium falciparum could be attenuated at the early liver stage by genetic engineering. The P. falciparum genetically attenuated parasites (GAPs) harbor individual deletions or simultaneous deletions of the sporozoite-expressed genes P52 and P36. Gene deletions were done by double-cross-over recombination to avoid genetic reversion of the knockout parasites. The gene deletions did not affect parasite replication throughout the erythrocytic cycle, gametocyte production, mosquito infections, and sporozoite production rates. However, the deletions caused parasite developmental arrest during hepatocyte infection. The double-gene deletion line exhibited a more severe intrahepatocytic growth defect compared with the single-gene deletion lines, and it did not persist. This defect was assessed in an in vitro liver-stage growth assay and in a chimeric mouse model harboring human hepatocytes. The strong phenotype of the double knockout GAP justifies its human testing as a whole-organism vaccine candidate using the established sporozoite challenge model. GAPs might provide a safe and reproducible platform to develop an efficacious whole-cell malaria vaccine that prevents infection at the preerythrocytic stage.

  12. Larval diet affects mosquito development and permissiveness to Plasmodium infection

    PubMed Central

    Linenberg, Inbar; Christophides, George K.; Gendrin, Mathilde

    2016-01-01

    The larval stages of malaria vector mosquitoes develop in water pools, feeding mostly on microorganisms and environmental detritus. Richness in the nutrient supply to larvae influences the development and metabolism of larvae and adults. Here, we investigated the effects of larval diet on the development, microbiota content and permissiveness to Plasmodium of Anopheles coluzzii. We tested three fish diets often used to rear mosquitoes in the laboratory, including two pelleted diets, Dr. Clarke’s Pool Pellets and Nishikoi Fish Pellets, and one flaked diet, Tetramin Fish-Flakes. Larvae grow and develop faster and produce bigger adults when feeding on both types of pellets compared with flakes. This correlates with a higher microbiota load in pellet-fed larvae, in agreement with the known positive effect of the microbiota on mosquito development. Larval diet also significantly influences the prevalence and intensity of Plasmodium berghei infection in adults, whereby Nishikoi Fish Pellets-fed larvae develop into adults that are highly permissive to parasites and survive longer after infection. This correlates with a lower amount of Enterobacteriaceae in the midgut microbiota. Together, our results shed light on the influence of larval feeding on mosquito development, microbiota and vector competence; they also provide useful data for mosquito rearing. PMID:27910908

  13. Plasmodium vivax Landscape in Brazil: Scenario and Challenges

    PubMed Central

    Siqueira, Andre M.; Mesones-Lapouble, Oscar; Marchesini, Paola; Sampaio, Vanderson de Souza; Brasil, Patricia; Tauil, Pedro L.; Fontes, Cor Jesus; Costa, Fabio T. M.; Daniel-Ribeiro, Cláudio Tadeu; Lacerda, Marcus V. G.; Damasceno, Camila P.; Santelli, Ana Carolina S.

    2016-01-01

    Brazil is the largest country of Latin America, with a considerable portion of its territoritory within the malaria-endemic Amazon region in the North. Furthermore, a considerable portion of its territory is located within the Amazon region in the north. As a result, Brazil has reported half of the total malaria cases in the Americas in the last four decades. Recent progress in malaria control has been accompanied by an increasing proportion of Plasmodium vivax, underscoring a need for a better understanding of management and control of this species and associated challenges. Among these challenges, the contribution of vivax malaria relapses, earlier production of gametocytes (compared with Plasmodium falciparum), inexistent methods to diagnose hypnozoite carriers, and decreasing efficacy of available antimalarials need to be addressed. Innovative tools, strategies, and technologies are needed to achieve further progress toward sustainable malaria elimination. Further difficulties also arise from dealing with the inherent socioeconomic and environmental particularities of the Amazon region and its dynamic changes. PMID:27708190

  14. Exoerythrocytic development of Plasmodium gallinaceum in the White Leghorn chicken☆

    PubMed Central

    Frevert, Ute; Späth, Gerald F.; Yee, Herman

    2008-01-01

    Plasmodium gallinaceum typically causes sub-clinical disease with low mortality in its primary host, the Indian jungle fowl Gallus sonnerati. Domestic chickens of European origin, however, are highly susceptible to this avian malaria parasite. Here we describe the development of P. gallinaceum in young White Leghorn chicks with emphasis on the primary exoerythrocytic phase of the infection. Using various regimens for infection, we found that P. gallinaceum induced a transient primary exoerythrocytic infection followed by a fulminant lethal erythrocytic phase. Prerequisite for the appearance of secondary exoerythrocytic stages was the development of a certain level of parasitemia. Once established, secondary exoerythrocytic stages could be propagated from bird to bird for several generations without causing fatalities. Infected brains contained large secondary exoerythrocytic stages in capillary endothelia, while in the liver primary and secondary erythrocytic stages developed primarily in Kupffer cells and remained smaller. At later stages, livers exhibited focal hepatocyte necrosis, Kupffer cell hyperplasia, stellate cell proliferation, inflammatory cell infiltration and granuloma formation. Because P. gallinaceum selectively infected Kupffer cells in the liver and caused a histopathology strikingly similar to mammalian species, this avian Plasmodium species represents an evolutionarily closely related model for studies on the hepatic phase of mammalian malaria. PMID:18005972

  15. Implications of Plasmodium vivax Biology for Control, Elimination, and Research

    PubMed Central

    Olliaro, Piero L.; Barnwell, John W.; Barry, Alyssa; Mendis, Kamini; Mueller, Ivo; Reeder, John C.; Shanks, G. Dennis; Snounou, Georges; Wongsrichanalai, Chansuda

    2016-01-01

    This paper summarizes our current understanding of the biology of Plasmodium vivax, how it differs from Plasmodium falciparum, and how these differences explain the need for P. vivax-tailored interventions. The article further pinpoints knowledge gaps where investments in research are needed to help identify and develop such specific interventions. The principal obstacles to reduce and eventually eliminate P. vivax reside in 1) its higher vectorial capacity compared with P. falciparum due to its ability to develop at lower temperature and over a shorter sporogonic cycle in the vector, allowing transmission in temperate zones and making it less sensitive to vector control measures that are otherwise effective on P. falciparum; 2) the presence of dormant liver forms (hypnozoites), sustaining multiple relapsing episodes from a single infectious bite that cannot be diagnosed and are not susceptible to any available antimalarial except primaquine, with routine deployment restricted by toxicity; 3) low parasite densities, which are difficult to detect with current diagnostics leading to missed diagnoses and delayed treatments (and protracted transmission), coupled with 4) transmission stages (gametocytes) occurring early in acute infections, before infection is diagnosed. PMID:27799636

  16. DNA Cloning of Plasmodium falciparum Circumsporozoite Gene: Amino Acid Sequence of Repetitive Epitope

    NASA Astrophysics Data System (ADS)

    Enea, Vincenzo; Ellis, Joan; Zavala, Fidel; Arnot, David E.; Asavanich, Achara; Masuda, Aoi; Quakyi, Isabella; Nussenzweig, Ruth S.

    1984-08-01

    A clone of complementary DNA encoding the circumsporozoite (CS) protein of the human malaria parasite Plasmodium falciparum has been isolated by screening an Escherichia coli complementary DNA library with a monoclonal antibody to the CS protein. The DNA sequence of the complementary DNA insert encodes a four-amino acid sequence: proline-asparagine-alanine-asparagine, tandemly repeated 23 times. The CS β -lactamase fusion protein specifically binds monoclonal antibodies to the CS protein and inhibits the binding of these antibodies to native Plasmodium falciparum CS protein. These findings provide a basis for the development of a vaccine against Plasmodium falciparum malaria.

  17. A genetic analysis of Plasmodium falciparum RNA polymerase II subunits in yeast.

    PubMed

    Hazoume, Adonis; Naderi, Kambiz; Candolfi, Ermanno; Kedinger, Claude; Chatton, Bruno; Vigneron, Marc

    2011-04-01

    RNA polymerase II is an essential nuclear multi subunit enzyme that transcribes nearly the whole genome. Its inhibition by the alpha-amanitin toxin leads to cell death. The enzyme of Plasmodium falciparum remains poorly characterized. Using a complementation assay in yeast as a genetic test, we demonstrate that five Plasmodium putative RNA polymerase subunits are indeed functional in vivo. The active site of this enzyme is built from the two largest subunits. Using site directed mutagenesis we were able to modify the active site of the yeast RNA polymerase II so as to introduce Plasmodium or human structural motifs. The resulting strains allow the screening of chemical libraries for potential specific inhibitors.

  18. Prevalence Patterns of Avian Plasmodium and Haemoproteus Parasites and the Influence of Host Relative Abundance in Southern China

    PubMed Central

    Zhang, Yanhua; Wu, Yuchun; Zhang, Qiang; Su, Dongdong; Zou, Fasheng

    2014-01-01

    Infectious diseases threaten the health and survival of wildlife populations. Consequently, relationships between host diversity, host abundance, and parasite infection are important aspects of disease ecology and conservation research. Here, we report on the prevalence patterns of avian Plasmodium and Haemoproteus infections and host relative abundance influence based on sampling 728 wild-caught birds representing 124 species at seven geographically widespread sites in southern China. The overall prevalence of two haemoprotozoan parasites, Plasmodium and Haemoproteus, was 29.5%, with 22.0% attributable to Haemoproteus and 7.8% to Plasmodium. Haemoproteus prevalence differed significantly among different avian host families, with the highest prevalence in Nectariniidae, Pycnonotidae and Muscicapidae, whereas Plasmodium prevalence varied significantly among host species. Seventy-nine mitochondrial lineages including 25 from Plasmodium and 54 from Haemoproteus were identified, 80% of which were described here for the first time. The phylogenetic relationships among these parasites indicated stronger host-species specificity for Haemoproteus than Plasmodium. Well-supported host-family (Timaliidae) specific clades were found in both Plasmodium and Haemoproteus. The Haemoproteus tree shows regional subclades, whereas the Plasmodium clades are “scattered” among different geographical regions. Interestingly, there were statistically significant variations in the prevalence of Plasmodium and Haemoproteus among the geographical regions. Furthermore, the prevalence of Plasmodium and Haemoproteus were not significantly correlated with host relative abundance. Further efforts will focus on exploring the relationships between parasite prevalence and sex, age, and immune defense of the host. PMID:24911323

  19. Prevalence patterns of avian Plasmodium and Haemoproteus parasites and the influence of host relative abundance in southern China.

    PubMed

    Zhang, Yanhua; Wu, Yuchun; Zhang, Qiang; Su, Dongdong; Zou, Fasheng

    2014-01-01

    Infectious diseases threaten the health and survival of wildlife populations. Consequently, relationships between host diversity, host abundance, and parasite infection are important aspects of disease ecology and conservation research. Here, we report on the prevalence patterns of avian Plasmodium and Haemoproteus infections and host relative abundance influence based on sampling 728 wild-caught birds representing 124 species at seven geographically widespread sites in southern China. The overall prevalence of two haemoprotozoan parasites, Plasmodium and Haemoproteus, was 29.5%, with 22.0% attributable to Haemoproteus and 7.8% to Plasmodium. Haemoproteus prevalence differed significantly among different avian host families, with the highest prevalence in Nectariniidae, Pycnonotidae and Muscicapidae, whereas Plasmodium prevalence varied significantly among host species. Seventy-nine mitochondrial lineages including 25 from Plasmodium and 54 from Haemoproteus were identified, 80% of which were described here for the first time. The phylogenetic relationships among these parasites indicated stronger host-species specificity for Haemoproteus than Plasmodium. Well-supported host-family (Timaliidae) specific clades were found in both Plasmodium and Haemoproteus. The Haemoproteus tree shows regional subclades, whereas the Plasmodium clades are "scattered" among different geographical regions. Interestingly, there were statistically significant variations in the prevalence of Plasmodium and Haemoproteus among the geographical regions. Furthermore, the prevalence of Plasmodium and Haemoproteus were not significantly correlated with host relative abundance. Further efforts will focus on exploring the relationships between parasite prevalence and sex, age, and immune defense of the host.

  20. Susceptibility of Anopheles campestris-like and Anopheles barbirostris species complexes to Plasmodium falciparum and Plasmodium vivax in Thailand.

    PubMed

    Thongsahuan, Sorawat; Baimai, Visut; Junkum, Anuluck; Saeung, Atiporn; Min, Gi-Sik; Joshi, Deepak; Park, Mi-Hyun; Somboon, Pradya; Suwonkerd, Wannapa; Tippawangkosol, Pongsri; Jariyapan, Narissara; Choochote, Wej

    2011-02-01

    Nine colonies of five sibling species members of Anopheles barbirostris complexes were experimentally infected with Plasmodium falciparum and Plasmodium vivax. They were then dissected eight and 14 days after feeding for oocyst and sporozoite rates, respectively, and compared with Anopheles cracens. The results revealed that Anopheles campestris-like Forms E (Chiang Mai) and F (Udon Thani) as well as An. barbirostris species A3 and A4 were non-potential vectors for P. falciparum because 0% oocyst rates were obtained, in comparison to the 86.67-100% oocyst rates recovered from An. cracens. Likewise, An. campestris-like Forms E (Sa Kaeo) and F (Ayuttaya), as well as An. barbirostris species A4, were non-potential vectors for P. vivax because 0% sporozoite rates were obtained, in comparison to the 85.71-92.31% sporozoite rates recovered from An. cracens. An. barbirostris species A1, A2 and A3 were low potential vectors for P. vivax because 9.09%, 6.67% and 11.76% sporozoite rates were obtained, respectively, in comparison to the 85.71-92.31% sporozoite rates recovered from An. cracens. An. campestris-like Forms B and E (Chiang Mai) were high-potential vectors for P. vivax because 66.67% and 64.29% sporozoite rates were obtained, respectively, in comparison to 90% sporozoite rates recovered from An. cracens.

  1. Functional analysis of Plasmodium vivax dihydrofolate reductase-thymidylate synthase genes through stable transformation of Plasmodium falciparum.

    PubMed

    Auliff, Alyson M; Balu, Bharath; Chen, Nanhua; O'Neil, Michael T; Cheng, Qin; Adams, John H

    2012-01-01

    Mechanisms of drug resistance in Plasmodium vivax have been difficult to study partially because of the difficulties in culturing the parasite in vitro. This hampers monitoring drug resistance and research to develop or evaluate new drugs. There is an urgent need for a novel method to study mechanisms of P. vivax drug resistance. In this paper we report the development and application of the first Plasmodium falciparum expression system to stably express P. vivax dhfr-ts alleles. We used the piggyBac transposition system for the rapid integration of wild-type, single mutant (117N) and quadruple mutant (57L/58R/61M/117T) pvdhfr-ts alleles into the P. falciparum genome. The majority (81%) of the integrations occurred in non-coding regions of the genome; however, the levels of pvdhfr transcription driven by the P. falciparum dhfr promoter were not different between integrants of non-coding and coding regions. The integrated quadruple pvdhfr mutant allele was much less susceptible to antifolates than the wild-type and single mutant pvdhfr alleles. The resistance phenotype was stable without drug pressure. All the integrated clones were susceptible to the novel antifolate JPC-2067. Therefore, the piggyBac expression system provides a novel and important tool to investigate drug resistance mechanisms and gene functions in P. vivax.

  2. Prevalence of mutation and phenotypic expression associated with sulfadoxine-pyrimethamine resistance in Plasmodium falciparum and Plasmodium vivax.

    PubMed

    Zakai, Haytham A; Khan, Wajihullah; Asma, Umme

    2013-09-01

    Therapeutic efficacy of sulfadoxine-pyrimethamine (SP), which is commonly used to treat falciparum malaria, was assessed in isolates of Plasmodium falciparum (Welch, 1897) and Plasmodium vivax (Grassi et Feletti, 1890) ofAligarh, Uttar Pradesh, North India and Taif, Saudi Arabia during 2011-2012. Both the species showed mutations in dihydrofolate reductase (DHFR) enzyme as they have common biochemical drug targets. Mutation rate for pfdhfr was higher compared to pvdhfr because the drug was mainly given to treat falciparum malaria. Since both the species coexist, P. vivax was also exposed to SP due to faulty species diagnosis or medication without specific diagnosis. Low level of mutations against SP in P. falciparum of Saudi isolates indicates that the SP combination is still effective for the treatment of falciparum malaria. Since SP is used as first-line of treatment because of high level of resistance against chloroquine (CQ), it may result in spread of higher level of mutations resulting in drug resistance and treatment failure in near future. Therefore, to avoid further higher mutations in the parasite, use of better treatment regimens such as artesunate combination therapy must be introduced against SP combination.

  3. Functional Analysis of Plasmodium vivax Dihydrofolate Reductase-Thymidylate Synthase Genes through Stable Transformation of Plasmodium falciparum

    PubMed Central

    Auliff, Alyson M.; Balu, Bharath; Chen, Nanhua; O’Neil, Michael T.; Cheng, Qin; Adams, John H.

    2012-01-01

    Mechanisms of drug resistance in Plasmodium vivax have been difficult to study partially because of the difficulties in culturing the parasite in vitro. This hampers monitoring drug resistance and research to develop or evaluate new drugs. There is an urgent need for a novel method to study mechanisms of P. vivax drug resistance. In this paper we report the development and application of the first Plasmodium falciparum expression system to stably express P. vivax dhfr-ts alleles. We used the piggyBac transposition system for the rapid integration of wild-type, single mutant (117N) and quadruple mutant (57L/58R/61M/117T) pvdhfr-ts alleles into the P. falciparum genome. The majority (81%) of the integrations occurred in non-coding regions of the genome; however, the levels of pvdhfr transcription driven by the P. falciparum dhfr promoter were not different between integrants of non-coding and coding regions. The integrated quadruple pvdhfr mutant allele was much less susceptible to antifolates than the wild-type and single mutant pvdhfr alleles. The resistance phenotype was stable without drug pressure. All the integrated clones were susceptible to the novel antifolate JPC-2067. Therefore, the piggyBac expression system provides a novel and important tool to investigate drug resistance mechanisms and gene functions in P. vivax. PMID:22792308

  4. Functional Antibodies against VAR2CSA in Nonpregnant Populations from Colombia Exposed to Plasmodium falciparum and Plasmodium vivax

    PubMed Central

    Doritchamou, Justin; Arango, Eliana M.; Cabrera, Ana; Arroyo, Maria Isabel; Kain, Kevin C.; Ndam, Nicaise Tuikue; Maestre, Amanda

    2014-01-01

    In pregnancy, parity-dependent immunity is observed in response to placental infection with Plasmodium falciparum. Antibodies recognize the surface antigen, VAR2CSA, expressed on infected red blood cells and inhibit cytoadherence to the placental tissue. In most settings of malaria endemicity, antibodies against VAR2CSA are predominantly observed in multigravid women and infrequently in men, children, and nulligravid women. However, in Colombia, we detected antibodies against multiple constructs of VAR2CSA among men and children with acute P. falciparum and Plasmodium vivax infection. The majority of men and children (>60%) had high levels of IgGs against three recombinant domains of VAR2CSA: DBL5ε, DBL3X, and ID1-ID2. Surprisingly, these antibodies were observed only in pregnant women, men, and children exposed either to P. falciparum or to P. vivax. Moreover, the anti-VAR2CSA antibodies are of high avidity and efficiently inhibit adherence of infected red blood cells to chondroitin sulfate A in vitro, suggesting that they are specific and functional. These unexpected results suggest that there may be genotypic or phenotypic differences in the parasites of this region or in the host response to either P. falciparum or P. vivax infection outside pregnancy. These findings may hold significant clinical relevance to the pathophysiology and outcome of malaria infections in this region. PMID:24686068

  5. Differential role of T regulatory and Th17 in Swiss mice infected with Plasmodium berghei ANKA and Plasmodium yoelii.

    PubMed

    Keswani, Tarun; Bhattacharyya, Arindam

    2014-06-01

    The outcome of malaria infection is determined, in part, by the balance of pro-inflammatory and regulatory immune responses. Host immune responses in disease including malaria are finely regulated by the opposing effects of Th17 and T regulatory (Treg) cells. Here we have examined the role of Treg cells and Th17 cells during malaria infection and find that low levels of Treg cells possibly influence the outcome of infections with the lethal strain of Plasmodium berghei ANKA (PbA). In contrast, high level of Treg cells may influence the outcome of nonlethal Plasmodium yoelii NXL (P. yoelii) infections. We observed decreased expressions of key regulators of Treg inductions-TGF-β, CD4IL-2 and IL-10 during PbA infection, whereas their expression remains high during P. yoelii infection. On the other hand TNF-α, IL-6, IFN-γ and IL-23 expression is high during PbA infection and lower during P. yoelii infection. Thus, results from this study suggest that the differential expression of Treg and Th17 might have a key role on host pathogenesis during malaria infection. The high level of IL-6 and low level of TGF-β may composite of the advantaged local microenvironment for the production of Th17 cells in the spleen of the PBA infected mice and vice verse during nonlethal P. yoelii.

  6. An innovative shape equation to quantify the morphological characteristics of parasitized red blood cells by Plasmodium falciparum and Plasmodium vivax.

    PubMed

    Karimi, Alireza; Navidbakhsh, Mahdi; Motevalli Haghi, Afsaneh; Faghihi, Shahab

    2013-04-01

    The morphology of red blood cells is affected significantly during maturation of malaria parasites, Plasmodium falciparum and Plasmodium vivax. A novel shape equation is presented that defines shape of parasitized red blood cells by P. falciparum (Pf-red blood cells) and P. vivax (Pv-red blood cells) at four stages of infection. The Giemsa-stained thin blood films are prepared using blood samples collected from healthy donors, patients having P. falciparum and P. vivax malaria. The diameter and thickness of healthy red blood cells plus Pf-red blood cells and Pv-red blood cells at each stage of infection are measured from their optical images using Olysia and Scanning Probe Image Processor softwares, respectively. Using diameters and thicknesses of parasitized red blood cells, a shape equation is fitted and relative two-dimensional shapes are plotted using MATHEMATICA. The shape of Pf-red blood cell drastically changes at ring stage as its thickness increases by 82%, while Pv-red blood cell remains biconcave (30% increase in thickness). By trophozoite and subsequent schizont stage, the Pf-red blood cell entirely loses its biconcave shape and becomes near spherical (diameter and thickness of ~8 µm). The Pv-red blood cell remains biconcave throughout the parasite development even though its volume increases. These results could have practical use for faster diagnosis, prediction, and treatment of human malaria and sickle-cell diseases.

  7. A qPCR-based Multiplex Assay for Detection of Wuchereria bancrofti, Plasmodium falciparum, and Plasmodium vivax DNA

    PubMed Central

    Rao, Ramakrishna U.; Huang, Yuefang; Bockarie, Moses J.; Susapu, Melinda; Laney, Sandra J.; Weil, Gary J.

    2009-01-01

    Summary The purpose of this study was to develop multiplex qPCR assays for simultaneous detection of Wuchereria bancrofti (Wb), Plasmodium falciparum (Pf) and P. vivax (Pv) in mosquitoes. We optimized the assays with purified DNA samples and then used these assays to test DNA samples isolated from Anopheles punctulatus mosquitoes collected in villages in Papua New Guinea where these infections are co-endemic. Singleplex assays detected Wb, Pf, and Pv DNA in 32%, 19% and 15% of the mosquito pools, respectively, either alone or together with other parasites. Multiplex assay results agreed with singleplex results in most cases. Overall parasite DNA rates in mosquitoes (estimated by the Poolscreen2) for Wb, Pf, and Pv were 4.9%, 2.7%, and 2.1%, respectively. Parasite DNA rates were consistently higher in blood fed mosquitoes than in host seeking mosquitoes. Our results show that multiplex qPCR can be used to detect and estimate prevalence rates for multiple parasite species in arthropod vectors. We believe that multiplex molecular xenodiagnosis has great potential as a tool for non-invasively assessing the distribution and prevalence of vector-borne pathogens such as W. bancrofti and Plasmodium spp. in human populations and for assessing the impact of interventions aimed at controlling or eliminating these diseases. PMID:18801545

  8. A plethora of Plasmodium species in wild apes: a source of human infection?

    PubMed Central

    Rayner, Julian C.; Liu, Weimin; Peeters, Martine; Sharp, Paul M.; Hahn, Beatrice H.

    2011-01-01

    Recent studies of captive and wild-living apes in Africa have uncovered evidence of numerous new Plasmodium species, one of which was identified as the immediate precursor of human Plasmodium falciparum. These findings raise the question whether wild apes could be a recurrent source of Plasmodium infections in humans. This question is not new, but was the subject of intense investigation by researchers in the first half of the last century. Re-examination of their work in the context of recent molecular findings provides a new framework to understand the diversity of Plasmodium species and to assess the risk of future cross-species transmissions to humans in the context of proposed malaria eradication programs. PMID:21354860

  9. Evolutionary origin of Plasmodium and other Apicomplexa based on rRNA genes.

    PubMed Central

    Escalante, A A; Ayala, F J

    1995-01-01

    We have explored the evolutionary history of the Apicomplexa and two related protistan phyla, Dinozoa and Ciliophora, by comparing the nucleotide sequences of small subunit ribosomal RNA genes. We conclude that the Plasmodium lineage, to which the malarial parasites belong, diverged from other apicomplexan lineages (piroplasmids and coccidians) several hundred million years ago, perhaps even before the Cambrian. The Plasmodium radiation, which gave rise to several species parasitic to humans, occurred approximately 129 million years ago; Plasmodium parasitism of humans has independently arisen several times. The origin of apicomplexans (Plasmodium), dinoflagellates, and ciliates may be > 1 billion years old, perhaps older than the three multicellular kingdoms of animals, plants, and fungi. Digenetic parasitism independently evolved several times in the Apicomplexa. PMID:7597031

  10. Molecular detection of Plasmodium in free-ranging birds and captive flamingos (Phoenicopterus chilensis) in Chicago.

    PubMed

    Thurber, Mary Irene; Gamble, Kathryn C; Krebs, Bethany; Goldberg, Tony L

    2014-12-01

    Frozen blood samples from 13 species of free-ranging birds (n = 65) and captive Chilean flamingos (Phoenicopterus chilensis) (n = 46) housed outdoors in the Chicago area were screened for Plasmodium. With the use of a modified polymerase chain reaction, 20/65 (30.8%) of free-ranging birds and 26/46 (56.5%) of flamingos were classified as positive for this parasite genus. DNA sequencing of the parasite cytochrome b gene in positive samples demonstrated that eight species of free-ranging birds were infected with five different Plasmodium spp. cytochrome b lineages, and all positive Chilean flamingos were infected with Plasmodium spp. cytochrome b lineages most closely related to organisms in the Novyella subgenus. These results show that Chilean flamingos may harbor subclinical malaria infections more frequently than previously estimated, and that they may have increased susceptibility to some Plasmodium species.

  11. Genomes of cryptic chimpanzee Plasmodium species reveal key evolutionary events leading to human malaria

    PubMed Central

    Sundararaman, Sesh A.; Plenderleith, Lindsey J.; Liu, Weimin; Loy, Dorothy E.; Learn, Gerald H.; Li, Yingying; Shaw, Katharina S.; Ayouba, Ahidjo; Peeters, Martine; Speede, Sheri; Shaw, George M.; Bushman, Frederic D.; Brisson, Dustin; Rayner, Julian C.; Sharp, Paul M.; Hahn, Beatrice H.

    2016-01-01

    African apes harbour at least six Plasmodium species of the subgenus Laverania, one of which gave rise to human Plasmodium falciparum. Here we use a selective amplification strategy to sequence the genome of chimpanzee parasites classified as Plasmodium reichenowi and Plasmodium gaboni based on the subgenomic fragments. Genome-wide analyses show that these parasites indeed represent distinct species, with no evidence of cross-species mating. Both P. reichenowi and P. gaboni are 10-fold more diverse than P. falciparum, indicating a very recent origin of the human parasite. We also find a remarkable Laverania-specific expansion of a multigene family involved in erythrocyte remodelling, and show that a short region on chromosome 4, which encodes two essential invasion genes, was horizontally transferred into a recent P. falciparum ancestor. Our results validate the selective amplification strategy for characterizing cryptic pathogen species, and reveal evolutionary events that likely predisposed the precursor of P. falciparum to colonize humans. PMID:27002652

  12. Genomes of cryptic chimpanzee Plasmodium species reveal key evolutionary events leading to human malaria.

    PubMed

    Sundararaman, Sesh A; Plenderleith, Lindsey J; Liu, Weimin; Loy, Dorothy E; Learn, Gerald H; Li, Yingying; Shaw, Katharina S; Ayouba, Ahidjo; Peeters, Martine; Speede, Sheri; Shaw, George M; Bushman, Frederic D; Brisson, Dustin; Rayner, Julian C; Sharp, Paul M; Hahn, Beatrice H

    2016-03-22

    African apes harbour at least six Plasmodium species of the subgenus Laverania, one of which gave rise to human Plasmodium falciparum. Here we use a selective amplification strategy to sequence the genome of chimpanzee parasites classified as Plasmodium reichenowi and Plasmodium gaboni based on the subgenomic fragments. Genome-wide analyses show that these parasites indeed represent distinct species, with no evidence of cross-species mating. Both P. reichenowi and P. gaboni are 10-fold more diverse than P. falciparum, indicating a very recent origin of the human parasite. We also find a remarkable Laverania-specific expansion of a multigene family involved in erythrocyte remodelling, and show that a short region on chromosome 4, which encodes two essential invasion genes, was horizontally transferred into a recent P. falciparum ancestor. Our results validate the selective amplification strategy for characterizing cryptic pathogen species, and reveal evolutionary events that likely predisposed the precursor of P. falciparum to colonize humans.

  13. Comparative assessment of genomic DNA extraction processes for Plasmodium: Identifying the appropriate method.

    PubMed

    Mann, Riti; Sharma, Supriya; Mishra, Neelima; Valecha, Neena; Anvikar, Anupkumar R

    2015-12-01

    Plasmodium DNA, in addition to being used for molecular diagnosis of malaria, find utility in monitoring patient responses to antimalarial drugs, drug resistance studies, genotyping and sequencing purposes. Over the years, numerous protocols have been proposed for extracting Plasmodium DNA from a variety of sources. Given that DNA isolation is fundamental to successful molecular studies, here we review the most commonly used methods for Plasmodium genomic DNA isolation, emphasizing their pros and cons. A comparison of these existing methods has been made, to evaluate their appropriateness for use in different applications and identify the method suitable for a particular laboratory based study. Selection of a suitable and accessible DNA extraction method for Plasmodium requires consideration of many factors, the most important being sensitivity, cost-effectiveness and, purity and stability of isolated DNA. Need of the hour is to accentuate on the development of a method that upholds well on all these parameters.

  14. Cytoadherence and virulence - the case of Plasmodium knowlesi malaria

    PubMed Central

    2012-01-01

    Background Cytoadherence of infected red blood cells to brain endothelium is causally implicated in malarial coma, one of the severe manifestations of falciparum malaria. Cytoadherence is mediated by specific binding of variant parasite antigens, expressed on the surface of infected erythrocytes, to endothelial receptors including, ICAM-1, VCAM and CD36. In fatal cases of severe falciparum malaria with coma, blood vessels in the brain are characteristically congested with infected erythrocytes. Brain sections from a fatal case of knowlesi malaria, but without coma, were similarly congested with infected erythrocytes. The objective of this study was to determine the binding phenotype of Plasmodium knowlesi infected human erythrocytes to recombinant human ICAM-1, VCAM and CD36. Methods Five patients with PCR-confirmed P. knowlesi malaria were recruited into the study with consent between April and August 2010. Pre-treatment venous blood was washed and cultured ex vivo to increase the proportion of schizont-infected erythrocytes. Cultured blood was seeded into Petri dishes with triplicate areas coated with ICAM-1, VCAM and CD36. Following incubation at 37°C for one hour the dishes were washed and the number of infected erythrocytes bound/mm2 to PBS control areas and to recombinant human ICAM-1 VCAM and CD36 coated areas were recorded. Each assay was performed in duplicate. Assay performance was monitored with the Plasmodium falciparum clone HB3. Results Blood samples were cultured ex vivo for up to 14.5 h (mean 11.3 ± 1.9 h) to increase the relative proportion of mature trophozoite and schizont-infected red blood cells to at least 50% (mean 65.8 ± 17.51%). Three (60%) isolates bound significantly to ICAM-1 and VCAM, one (20%) isolate bound to VCAM and none of the five bound significantly to CD36. Conclusions Plasmodium knowlesi infected erythrocytes from human subjects bind in a specific but variable manner to the inducible endothelial receptors ICAM-1 and VCAM

  15. Plasmodium vivax Malaria Endemicity in Indonesia in 2010

    PubMed Central

    Elyazar, Iqbal R. F.; Gething, Peter W.; Patil, Anand P.; Rogayah, Hanifah; Sariwati, Elvieda; Palupi, Niken W.; Tarmizi, Siti N.; Kusriastuti, Rita; Baird, J. Kevin; Hay, Simon I.

    2012-01-01

    Background Plasmodium vivax imposes substantial morbidity and mortality burdens in endemic zones. Detailed understanding of the contemporary spatial distribution of this parasite is needed to combat it. We used model based geostatistics (MBG) techniques to generate a contemporary map of risk of Plasmodium vivax malaria in Indonesia in 2010. Methods Plasmodium vivax Annual Parasite Incidence data (2006–2008) and temperature masks were used to map P. vivax transmission limits. A total of 4,658 community surveys of P. vivax parasite rate (PvPR) were identified (1985–2010) for mapping quantitative estimates of contemporary endemicity within those limits. After error-checking a total of 4,457 points were included into a national database of age-standardized 1–99 year old PvPR data. A Bayesian MBG procedure created a predicted PvPR1–99 endemicity surface with uncertainty estimates. Population at risk estimates were derived with reference to a 2010 human population surface. Results We estimated 129.6 million people in Indonesia lived at risk of P. vivax transmission in 2010. Among these, 79.3% inhabited unstable transmission areas and 20.7% resided in stable transmission areas. In western Indonesia, the predicted P. vivax prevalence was uniformly low. Over 70% of the population at risk in this region lived on Java and Bali islands, where little malaria transmission occurs. High predicted prevalence areas were observed in the Lesser Sundas, Maluku and Papua. In general, prediction uncertainty was relatively low in the west and high in the east. Conclusion Most Indonesians living with endemic P. vivax experience relatively low risk of infection. However, blood surveys for this parasite are likely relatively insensitive and certainly do not detect the dormant liver stage reservoir of infection. The prospects for P. vivax elimination would be improved with deeper understanding of glucose-6-phosphate dehydrogenase deficiency (G6PDd) distribution, anti-relapse therapy

  16. Increased detection of Plasmodium knowlesi in Sandakan division, Sabah as revealed by PlasmoNex™

    PubMed Central

    2013-01-01

    Background Plasmodium knowlesi is a simian malaria parasite that is widespread in humans in Malaysian Borneo. However, little is known about the incidence and distribution of this parasite in the Sandakan division, Malaysian Borneo. Therefore, the aim of the present epidemiological study was to investigate the incidence and distribution of P. knowlesi as well as other Plasmodium species in this division based on a most recent developed hexaplex PCR system (PlasmoNex™). Methods A total of 189 whole blood samples were collected from Telupid Health Clinic, Sabah, Malaysia, from 2008 to 2011. All patients who participated in the study were microscopically malaria positive before recruitment. Complete demographic details and haematological profiles were obtained from 85 patients (13 females and 72 males). Identification of Plasmodium species was conducted using PlasmoNex™ targeting the 18S ssu rRNA gene. Results A total of 178 samples were positive for Plasmodium species by using PlasmoNex™. Plasmodium falciparum was identified in 68 samples (38.2%) followed by 64 cases (36.0%) of Plasmodium vivax, 42 (23.6%) cases of P. knowlesi, two (1.1%) cases of Plasmodium malariae and two (1.1%) mixed-species infections (i e, P. vivax/P. falciparum). Thirty-five PlasmoNex™ positive P. knowlesi samples were misdiagnosed as P. malariae by microscopy. Plasmodium knowlesi was detected in all four districts of Sandakan division with the highest incidence in the Kinabatangan district. Thrombocytopaenia and anaemia showed to be the most frequent malaria-associated haematological complications in this study. Conclusions The discovery of P. knowlesi in Sandakan division showed that prospective studies on the epidemiological risk factors and transmission dynamics of P. knowlesi in these areas are crucial in order to develop strategies for effective malaria control. The availability of advanced diagnostic tool PlasmoNex™ enhanced the accuracy and accelerated the speed in the

  17. Species and genotype diversity of Plasmodium in malaria patients from Gabon analysed by next generation sequencing.

    PubMed

    Lalremruata, Albert; Jeyaraj, Sankarganesh; Engleitner, Thomas; Joanny, Fanny; Lang, Annika; Bélard, Sabine; Mombo-Ngoma, Ghyslain; Ramharter, Michael; Kremsner, Peter G; Mordmüller, Benjamin; Held, Jana

    2017-10-03

    Six Plasmodium species are known to naturally infect humans. Mixed species infections occur regularly but morphological discrimination by microscopy is difficult and multiplicity of infection (MOI) can only be evaluated by molecular methods. This study investigated the complexity of Plasmodium infections in patients treated for microscopically detected non-falciparum or mixed species malaria in Gabon. Ultra-deep sequencing of nucleus (18S rRNA), mitochondrion, and apicoplast encoded genes was used to evaluate Plasmodium species diversity and MOI in 46 symptomatic Gabonese patients with microscopically diagnosed non-falciparum or mixed species malaria. Deep sequencing revealed a large complexity of confections in patients with uncomplicated malaria, both on species and genotype levels. Mixed infections involved up to four parasite species (Plasmodium falciparum, Plasmodium malariae, Plasmodium ovale curtisi, and P. ovale wallikeri). Multiple genotypes from each species were determined from the asexual 18S rRNA gene. 17 of 46 samples (37%) harboured multiple genotypes of at least one Plasmodium species. The number of genotypes per sample (MOI) was highest in P. malariae (n = 4), followed by P. ovale curtisi (n = 3), P. ovale wallikeri (n = 3), and P. falciparum (n = 2). The highest combined genotype complexity in samples that contained mixed-species infections was seven. Ultra-deep sequencing showed an unexpected breadth of Plasmodium species and within species diversity in clinical samples. MOI of P. ovale curtisi, P. ovale wallikeri and P. malariae infections were higher than anticipated and contribute significantly to the burden of malaria in Gabon.

  18. [Survey on status of staff for Plasmodium microscopy examinations in Changzhou City].

    PubMed

    Xie, Yi-Qing; He, Ming-Zhen; Zhu, Shi-Ying; Zou, Yong-Gen; Chen, Hong

    2014-02-01

    To understand the current state of staff for Plasmodium microscopy examinations in Changzhou City in the early stage of eliminating malaria action, so as to provide the evidence for achieving the target of malaria elimination. The staff for Plasmodium microscopy examinations from medical institutions and centers for disease control and prevention at different levels were investigated by questionnaires and tests of the malaria related theory and microscopic operation. Totally 95 people were investigated, and among them, 40.0% had college degree and 45.3% were university educated. There were 18.9% of them working on Plasmodium microscopy examinations for less than 1 year, 40.0% for 2-5 years, 18.9% for 6-10 years and 22.1% for more than 10 years. The numbers of person-time of provincial and municipal level training, district-level training, and unit-level training in the last year were 0.57, 0.59, and 0.14, respectively. Totally 18.9% of them had the experience of finding Plasmodium at work, and 97.9% of them considered it was necessary or very necessary to do Plasmodium microscopy examinations. However, 57.9% and 8.4% of them considered Plasmodium microscopy examinations increased their work load and work difficulty, respectively. The average correct rates of knowledge tests on malaria before and after training were 72.5% and 91.6% respectively (P < 0.05). The average mark of Plasmodium microscopic tests was 25.3 points (full mark being 50 points), and the passing rate (> or = 30 points) was 58.9%. The working experience of staff for Plasmodium microscopy examinations in Changzhou City is relatively poor, and the related training should be enhanced.

  19. A sensitive, specific and reproducible real-time polymerase chain reaction method for detection of Plasmodium vivax and Plasmodium falciparum infection in field-collected anophelines.

    PubMed

    Bickersmith, Sara A; Lainhart, William; Moreno, Marta; Chu, Virginia M; Vinetz, Joseph M; Conn, Jan E

    2015-06-01

    We describe a simple method for detection of Plasmodium vivax and Plasmodium falciparum infection in anophelines using a triplex TaqMan real-time polymerase chain reaction (PCR) assay (18S rRNA). We tested the assay on Anopheles darlingi and Anopheles stephensi colony mosquitoes fed with Plasmodium-infected blood meals and in duplicate on field collected An. darlingi. We compared the real-time PCR results of colony-infected and field collected An. darlingi, separately, to a conventional PCR method. We determined that a cytochrome b-PCR method was only 3.33% as sensitive and 93.38% as specific as our real-time PCR assay with field-collected samples. We demonstrate that this assay is sensitive, specific and reproducible.

  20. Multigenomic Delineation of Plasmodium Species of the Laverania Subgenus Infecting Wild-Living Chimpanzees and Gorillas

    PubMed Central

    Liu, Weimin; Sundararaman, Sesh A.; Loy, Dorothy E.; Learn, Gerald H.; Li, Yingying; Plenderleith, Lindsey J.; Ndjango, Jean-Bosco N.; Speede, Sheri; Atencia, Rebeca; Cox, Debby; Shaw, George M.; Ayouba, Ahidjo; Peeters, Martine; Rayner, Julian C.; Hahn, Beatrice H.; Sharp, Paul M.

    2016-01-01

    Plasmodium falciparum, the major cause of malaria morbidity and mortality worldwide, is only distantly related to other human malaria parasites and has thus been placed in a separate subgenus, termed Laverania. Parasites morphologically similar to P. falciparum have been identified in African apes, but only one other Laverania species, Plasmodium reichenowi from chimpanzees, has been formally described. Although recent studies have pointed to the existence of additional Laverania species, their precise number and host associations remain uncertain, primarily because of limited sampling and a paucity of parasite sequences other than from mitochondrial DNA. To address this, we used limiting dilution polymerase chain reaction to amplify additional parasite sequences from a large number of chimpanzee and gorilla blood and fecal samples collected at two sanctuaries and 30 field sites across equatorial Africa. Phylogenetic analyses of more than 2,000 new sequences derived from the mitochondrial, nuclear, and apicoplast genomes revealed six divergent and well-supported clades within the Laverania parasite group. Although two of these clades exhibited deep subdivisions in phylogenies estimated from organelle gene sequences, these sublineages were geographically defined and not present in trees from four unlinked nuclear loci. This greatly expanded sequence data set thus confirms six, and not seven or more, ape Laverania species, of which P. reichenowi, Plasmodium gaboni, and Plasmodium billcollinsi only infect chimpanzees, whereas Plasmodium praefalciparum, Plasmodium adleri, and Pladmodium blacklocki only infect gorillas. The new sequence data also confirm the P. praefalciparum origin of human P. falciparum. PMID:27289102

  1. Plasmodium immobilization of Physarella oblonga (Berk. & Curt.) Morgan (Myxomycetes) using kaolinite as a matrix of entrapment.

    PubMed

    Ribeiro, Sheyla M; Cavalcanti, Laise H; Pereira, Eugênia C; Silva, Nicácio H

    2003-01-01

    The possibility of using kaolinite-immobilized plasmodium fragments of Physarella oblonga (Berk. & Curt.) Morgan to maintain their metabolic activity was examined. The immobilization process was carried out with 1 mg of plasmodium of P. oblonga entrapped in 10 g of kaolinite. Sodium acetate (1 mM) was used as a metabolic precursor. The collection of fractions was carried out during a one month period, and extracted with ether/ethyl acetate and chloroform/acetonitrile. The extractions from plasmodium in natura were accomplished with the same solvents. The extracts obtained were analyzed in a spectrophotometer at 266 nm and 310 nm, and by thin layer chromatography to assess the productivity of the immobilized plasmodium. The absorbances of the extracts in both wavelengths and the chromatographic tests showed the synthesis of compounds by the immobilized material. Three chromatographic spots were observed in the extracts obtained from the immobilized plasmodium. Two spots coincided with the R(f) values and coloration of the spots observed for the material in natura used as a reference. The kaolinite-immobilized plasmodium of P. oblonga can remain metabolically active for at least one month at room temperature and ambient light conditions.

  2. Anopheles gambiae Circumsporozoite Protein–Binding Protein Facilitates Plasmodium Infection of Mosquito Salivary Glands

    PubMed Central

    Wang, Jiuling; Zhang, Yue; Zhao, Yang O.; Li, Michelle W. M.; Zhang, Lili; Dragovic, Srdjan; Abraham, Nabil M.; Fikrig, Erol

    2013-01-01

    Malaria, a mosquito-borne disease caused by Plasmodium species, causes substantial morbidity and mortality throughout the world. Plasmodium sporozoites mature in oocysts formed in the mosquito gut wall and then invade the salivary glands, where they remain until transmitted to the vertebrate host during a mosquito bite. The Plasmodium circumsporozoite protein (CSP) binds to salivary glands and plays a role in the invasion of this organ by sporozoites. We identified an Anopheles salivary gland protein, named CSP-binding protein (CSPBP), that interacts with CSP. Downregulation of CSPBP in mosquito salivary glands inhibited invasion by Plasmodium organisms. In vivo bioassays showed that mosquitoes that were fed blood with CSPBP antibody displayed a 25% and 90% reduction in the parasite load in infected salivary glands 14 and 18 days after the blood meal, respectively. These results suggest that CSPBP is important for the infection of the mosquito salivary gland by Plasmodium organisms and that blocking CSPBP can interfere with the Plasmodium life cycle. PMID:23801601

  3. A natural Anopheles-associated Penicillium chrysogenum enhances mosquito susceptibility to Plasmodium infection.

    PubMed

    Angleró-Rodríguez, Yesseinia I; Blumberg, Benjamin J; Dong, Yuemei; Sandiford, Simone L; Pike, Andrew; Clayton, April M; Dimopoulos, George

    2016-09-28

    Whereas studies have extensively examined the ability of bacteria to influence Plasmodium infection in the mosquito, the tripartite interactions between non-entomopathogenic fungi, mosquitoes, and Plasmodium parasites remain largely uncharacterized. Here we report the isolation of a common mosquito-associated ascomycete fungus, Penicillium chrysogenum, from the midgut of field-caught Anopheles mosquitoes. Although the presence of Pe. chrysogenum in the Anopheles gambiae midgut does not affect mosquito survival, it renders the mosquito significantly more susceptible to Plasmodium infection through a secreted heat-stable factor. We further provide evidence that the mechanism of the fungus-mediated modulation of mosquito susceptibility to Plasmodium involves an upregulation of the insect's ornithine decarboxylase gene, which sequesters arginine for polyamine biosynthesis. Arginine plays an important role in the mosquito's anti-Plasmodium defense as a substrate of nitric oxide production, and its availability therefore has a direct impact on the mosquito's susceptibility to the parasite. While this type of immunomodulatory mechanism has already been demonstrated in other host-pathogen interaction systems, this is the first report of a mosquito-associated fungus that can suppress the mosquito's innate immune system in a way that would favor Plasmodium infection and possibly malaria transmission.

  4. A natural Anopheles-associated Penicillium chrysogenum enhances mosquito susceptibility to Plasmodium infection

    PubMed Central

    Angleró-Rodríguez, Yesseinia I.; Blumberg, Benjamin J.; Dong, Yuemei; Sandiford, Simone L.; Pike, Andrew; Clayton, April M.; Dimopoulos, George

    2016-01-01

    Whereas studies have extensively examined the ability of bacteria to influence Plasmodium infection in the mosquito, the tripartite interactions between non-entomopathogenic fungi, mosquitoes, and Plasmodium parasites remain largely uncharacterized. Here we report the isolation of a common mosquito-associated ascomycete fungus, Penicillium chrysogenum, from the midgut of field-caught Anopheles mosquitoes. Although the presence of Pe. chrysogenum in the Anopheles gambiae midgut does not affect mosquito survival, it renders the mosquito significantly more susceptible to Plasmodium infection through a secreted heat-stable factor. We further provide evidence that the mechanism of the fungus-mediated modulation of mosquito susceptibility to Plasmodium involves an upregulation of the insect’s ornithine decarboxylase gene, which sequesters arginine for polyamine biosynthesis. Arginine plays an important role in the mosquito’s anti-Plasmodium defense as a substrate of nitric oxide production, and its availability therefore has a direct impact on the mosquito’s susceptibility to the parasite. While this type of immunomodulatory mechanism has already been demonstrated in other host-pathogen interaction systems, this is the first report of a mosquito-associated fungus that can suppress the mosquito’s innate immune system in a way that would favor Plasmodium infection and possibly malaria transmission. PMID:27678168

  5. Exploring Drug Targets in Isoprenoid Biosynthetic Pathway for Plasmodium falciparum.

    PubMed

    Qidwai, Tabish; Jamal, Farrukh; Khan, Mohd Y; Sharma, Bechan

    2014-01-01

    Emergence of rapid drug resistance to existing antimalarial drugs in Plasmodium falciparum has created the need for prediction of novel targets as well as leads derived from original molecules with improved activity against a validated drug target. The malaria parasite has a plant plastid-like apicoplast. To overcome the problem of falciparum malaria, the metabolic pathways in parasite apicoplast have been used as antimalarial drug targets. Among several pathways in apicoplast, isoprenoid biosynthesis is one of the important pathways for parasite as its multiplication in human erythrocytes requires isoprenoids. Therefore targeting this pathway and exploring leads with improved activity is a highly attractive approach. This report has explored progress towards the study of proteins and inhibitors of isoprenoid biosynthesis pathway. For more comprehensive analysis, antimalarial drug-protein interaction has been covered.

  6. Three Divergent Subpopulations of the Malaria Parasite Plasmodium knowlesi

    PubMed Central

    Lin, Lee C.; Rovie-Ryan, Jeffrine J.; Kadir, Khamisah A.; Anderios, Fread; Hisam, Shamilah; Sharma, Reuben S.K.; Singh, Balbir; Conway, David J.

    2017-01-01

    Multilocus microsatellite genotyping of Plasmodium knowlesi isolates previously indicated 2 divergent parasite subpopulations in humans on the island of Borneo, each associated with a different macaque reservoir host species. Geographic divergence was also apparent, and independent sequence data have indicated particularly deep divergence between parasites from mainland Southeast Asia and Borneo. To resolve the overall population structure, multilocus microsatellite genotyping was conducted on a new sample of 182 P. knowlesi infections (obtained from 134 humans and 48 wild macaques) from diverse areas of Malaysia, first analyzed separately and then in combination with previous data. All analyses confirmed 2 divergent clusters of human cases in Malaysian Borneo, associated with long-tailed macaques and pig-tailed macaques, and a third cluster in humans and most macaques in peninsular Malaysia. High levels of pairwise divergence between each of these sympatric and allopatric subpopulations have implications for the epidemiology and control of this zoonotic species. PMID:28322705

  7. Endoplasmic motility spectral characteristics in plasmodium of Physarum polycephalum

    NASA Astrophysics Data System (ADS)

    Avsievich, T. I.; Ghaleb, K. E. S.; Frolov, S. V.; Proskurin, S. G.

    2015-03-01

    Spectral Fourier analysis of experimentally acquired velocity time dependencies, V(t), of shuttle endoplasmic motility in an isolated strand of plasmodium of slime mold Physarum Polycephalum has been realized. V(t) registration was performed in normal conditions and after the treatment by respiration inhibitors, which lead to a complete cessation of endoplasmic motion in the strand. Spectral analysis of the velocity time dependences of the endoplasm allows obtaining two distinct harmonic components in the spectra. Their ratio appeared to be constant in all cases, ν2/ν1=1.97±0.17. After the inhibitors are washed out respiratory system becomes normal, gradually restoring the activity of both harmonic oscillatory sources with time. Simulated velocity time dependences correspond to experimental data with good accuracy.

  8. Symmetrical peripheral gangrene due to Plasmodium falciparum malaria

    PubMed Central

    Abdali, Nasar; Malik, Azharuddin Mohammed; Kamal, Athar; Ahmad, Mehtab

    2014-01-01

    A 45-year-old man presented with a 4-day history of high-grade fever with rigours and a 2-day history of painful bluish black discolouration of extremities (acrocyanosis). He was haemodynamically stable and all peripheral pulses palpable, but the extremities were cold with gangrene involving bilateral fingers and toes. Mild splenomegaly was present on abdominal examination but rest of the physical examinations were normal. On investigating he was found to have anaemia, thrombocytopaenia with gametocytes of Plasmodium falciparum on peripheral blood smear. His blood was uncoagulable during performance of prothrombin time with a raised D-dimer. Oxygen saturation was normal and the arterial Doppler test showed reduced blood flow to the extremities. A diagnosis of complicated P. falciparum malaria with disseminated intravascular coagulation (DIC) leading to symmetrical peripheral gangrene was performed. Artemisinin combination therapy was started and heparin was given for DIC. A final line of demarcation of gangrene started forming by 12th day. PMID:24862424

  9. Symmetrical peripheral gangrene: A rare complication of plasmodium falciparum malaria

    PubMed Central

    Rana, Atul; Singh, DP; Kaur, Gurdeep; Verma, SK; Mahur, Hemant

    2015-01-01

    Malaria, the most important of the parasitic diseases of humans, is transmitted in 108 countries containing 3 billion people and causes nearly 1 million deaths each year. With the re-emergence of malaria various life-threatening complications of malaria have been observed. Unarousable coma/cerebral malaria, severe normochromic, normocytic anemia, renal failure, pulmonary edema/adult respiratory distress syndrome, hypoglycemia, hypotension/shock, bleeding/disseminated intravascular coagulation (DIC), hemoglobinuria and jaundice are few of the common complications of severe malaria. Symmetrical peripheral gangrene (SPG) has been reported as a rare complication of malaria. We report a rare and unique case of Plasmodium falciparum malaria complicated by DIC, severe normocytic normochromic anemia, and SPG. PMID:26629458

  10. The epidemiology of Plasmodium vivax circumsporozoite protein polymorphs in Thailand.

    PubMed

    Suwanabun, N; Sattabongkot, J; Wirtz, R A; Rosenberg, R

    1994-04-01

    Enzyme-linked immunosorbent assays (ELISAs) highly specific for the characteristic repeat units of the circumsporozoite proteins of the VK 247 and VK 210 polymorphs of Plasmodium vivax were used to test sporozoites produced by feeding mosquitoes on 1,711 human volunteers presenting at four locations in Thailand over five years. There was no evidence for the existence of any polymorph other than the two already described. Based on the ELISAs, the overall prevalence of the VK 247 type was 29.5%, including those found mixed with VK 210. Relative proportions of VK 210 and VK 247 differed between collection sites. At all places, the ratio of VK 210 to VK 247 was significantly higher at the end of the nontransmission season than it was later during the annual monsoon, suggesting that there may be intrinsic biological differences between the polymorphs that affect their survival.

  11. Plasmodium berghei ANKA causes intestinal malaria associated with dysbiosis.

    PubMed

    Taniguchi, Tomoyo; Miyauchi, Eiji; Nakamura, Shota; Hirai, Makoto; Suzue, Kazutomo; Imai, Takashi; Nomura, Takahiro; Handa, Tadashi; Okada, Hiroko; Shimokawa, Chikako; Onishi, Risa; Olia, Alex; Hirata, Jun; Tomita, Haruyoshi; Ohno, Hiroshi; Horii, Toshihiro; Hisaeda, Hajime

    2015-10-27

    Gastrointestinal symptoms, such as abdominal pain and diarrhea, are frequently observed in patients with Plasmodium falciparum malaria. However, the correlation between malaria intestinal pathology and intestinal microbiota has not been investigated. In the present study, infection of C57BL/6 mice with P. berghei ANKA (PbA) caused intestinal pathological changes, such as detachment of epithelia in the small intestines and increased intestinal permeability, which correlated with development with experimental cerebral malaria (ECM). Notably, an apparent dysbiosis occurred, characterized by a reduction of Firmicutes and an increase in Proteobacteria. Furthermore, some genera of microbiota correlated with parasite growth and/or ECM development. By contrast, BALB/c mice are resistant to ECM and exhibit milder intestinal pathology and dysbiosis. These results indicate that the severity of cerebral and intestinal pathology coincides with the degree of alteration in microbiota. This is the first report demonstrating that malaria affects intestinal microbiota and causes dysbiosis.

  12. Energy-saving with low dimensional network in Physarum plasmodium

    NASA Astrophysics Data System (ADS)

    Takamatsu, Atsuko; Gomi, Takuma; Endo, Tatsuya; Hirai, Tomo; Sasaki, Takato

    2017-04-01

    An adaptation process in the transportation network of Physarum plasmodium was investigated by measuring oxygen consumption during network formation. Simultaneously, the fractal dimension as a measure of network structure was estimated. Oxygen consumption decreased during the development of the network, whereas the network structure changed from a thin mesh-type to a thick dendritic type. Our data suggested that the morphology of the plasmodial network governed energy consumption; a low dimensional network in the sense of the fractal dimension reduced energy consumption. These data were supported by experimental results excluding biological reasons, such as differences in starvation/nutrient-fullness states, and aspects of mitochondrial distribution. Model analysis using the Physarum algorithm with volume conservation constraints confirmed the above findings.

  13. Haem-activated promiscuous targeting of artemisinin in Plasmodium falciparum

    PubMed Central

    Wang, Jigang; Zhang, Chong-Jing; Chia, Wan Ni; Loh, Cheryl C. Y.; Li, Zhengjun; Lee, Yew Mun; He, Yingke; Yuan, Li-Xia; Lim, Teck Kwang; Liu, Min; Liew, Chin Xia; Lee, Yan Quan; Zhang, Jianbin; Lu, Nianci; Lim, Chwee Teck; Hua, Zi-Chun; Liu, Bin; Shen, Han-Ming; Tan, Kevin S. W.; Lin, Qingsong

    2015-01-01

    The mechanism of action of artemisinin and its derivatives, the most potent of the anti-malarial drugs, is not completely understood. Here we present an unbiased chemical proteomics analysis to directly explore this mechanism in Plasmodium falciparum. We use an alkyne-tagged artemisinin analogue coupled with biotin to identify 124 artemisinin covalent binding protein targets, many of which are involved in the essential biological processes of the parasite. Such a broad targeting spectrum disrupts the biochemical landscape of the parasite and causes its death. Furthermore, using alkyne-tagged artemisinin coupled with a fluorescent dye to monitor protein binding, we show that haem, rather than free ferrous iron, is predominantly responsible for artemisinin activation. The haem derives primarily from the parasite's haem biosynthesis pathway at the early ring stage and from haemoglobin digestion at the latter stages. Our results support a unifying model to explain the action and specificity of artemisinin in parasite killing. PMID:26694030

  14. Plasmodium falciparum: growth response to potassium channel blocking compounds.

    PubMed

    Waller, Karena L; Kim, Kami; McDonald, Thomas V

    2008-11-01

    Potassium channels are essential for cell survival and regulate the cell membrane potential and electrochemical gradient. During its lifecycle, Plasmodium falciparum parasites must rapidly adapt to dramatically variant ionic conditions within the mosquito mid-gut, the hepatocyte and red blood cell (RBC) cytosols, and the human circulatory system. To probe the participation of K(+) channels in parasite viability, growth response assays were performed in which asexual stage P. falciparum parasites were cultured in the presence of various Ca(2+)-activated K(+) channel blocking compounds. These data describe the novel anti-malarial effects of bicuculline methiodide and tubocurarine chloride and the novel lack of effect of apamine and verruculogen. Taken together, the data herein imply the presence of K(+) channels, or other parasite-specific targets, in P. falciparum-infected RBCs that are sensitive to blockade with Ca(2+)-activated K(+) channel blocking compounds.

  15. African origin of the malaria parasite Plasmodium vivax

    PubMed Central

    Liu, Weimin; Li, Yingying; Shaw, Katharina S.; Learn, Gerald H.; Plenderleith, Lindsey J.; Malenke, Jordan A.; Sundararaman, Sesh A.; Ramirez, Miguel A.; Crystal, Patricia A.; Smith, Andrew G.; Bibollet-Ruche, Frederic; Ayouba, Ahidjo; Locatelli, Sabrina; Esteban, Amandine; Mouacha, Fatima; Guichet, Emilande; Butel, Christelle; Ahuka-Mundeke, Steve; Inogwabini, Bila-Isia; Ndjango, Jean-Bosco N.; Speede, Sheri; Sanz, Crickette M.; Morgan, David B.; Gonder, Mary K.; Kranzusch, Philip J.; Walsh, Peter D.; Georgiev, Alexander V.; Muller, Martin N.; Piel, Alex K.; Stewart, Fiona A.; Wilson, Michael L.; Pusey, Anne E.; Cui, Liwang; Wang, Zenglei; Färnert, Anna; Sutherland, Colin J.; Nolder, Debbie; Hart, John A.; Hart, Terese B.; Bertolani, Paco; Gillis, Amethyst; LeBreton, Matthew; Tafon, Babila; Kiyang, John; Djoko, Cyrille F.; Schneider, Bradley S.; Wolfe, Nathan D.; Mpoudi-Ngole, Eitel; Delaporte, Eric; Carter, Richard; Culleton, Richard L.; Shaw, George M.; Rayner, Julian C.; Peeters, Martine; Hahn, Beatrice H.; Sharp, Paul M.

    2014-01-01

    Plasmodium vivax is the leading cause of human malaria in Asia and Latin America but is absent from most of central Africa due to the near fixation of a mutation that inhibits the expression of its receptor, the Duffy antigen, on human erythrocytes. The emergence of this protective allele is not understood because P. vivax is believed to have originated in Asia. Here we show, using a non-invasive approach, that wild chimpanzees and gorillas throughout central Africa are endemically infected with parasites that are closely related to human P. vivax. Sequence analyses reveal that ape parasites lack host specificity and are much more diverse than human parasites, which form a monophyletic lineage within the ape parasite radiation. These findings indicate that human P. vivax is of African origin and likely selected for the Duffy-negative mutation. All extant human P. vivax parasites are derived from a single ancestor that escaped out of Africa. PMID:24557500

  16. Multiple populations of artemisinin-resistant Plasmodium falciparum in Cambodia

    PubMed Central

    Miotto, Olivo; Almagro-Garcia, Jacob; Manske, Magnus; MacInnis, Bronwyn; Campino, Susana; Rockett, Kirk A; Amaratunga, Chanaki; Lim, Pharath; Suon, Seila; Sreng, Sokunthea; Anderson, Jennifer M; Duong, Socheat; Nguon, Chea; Chuor, Char Meng; Saunders, David; Se, Youry; Lon, Chantap; Fukuda, Mark M; Amenga-Etego, Lucas; Hodgson, Abraham VO; Asoala, Victor; Imwong, Mallika; Takala-Harrison, Shannon; Nosten, Francois; Su, Xin-zhuan; Ringwald, Pascal; Ariey, Frédéric; Dolecek, Christiane; Hien, Tran Tinh; Boni, Maciej F; Thai, Cao Quang; Amambua-Ngwa, Alfred; Conway, David J; Djimdé, Abdoulaye A; Doumbo, Ogobara K; Zongo, Issaka; Ouedraogo, Jean-Bosco; Alcock, Daniel; Drury, Eleanor; Auburn, Sarah; Koch, Oliver; Sanders, Mandy; Hubbart, Christina; Maslen, Gareth; Ruano-Rubio, Valentin; Jyothi, Dushyanth; Miles, Alistair; O’Brien, John; Gamble, Chris; Oyola, Samuel O; Rayner, Julian C; Newbold, Chris I; Berriman, Matthew; Spencer, Chris CA; McVean, Gilean; Day, Nicholas P; White, Nicholas J; Bethell, Delia; Dondorp, Arjen M; Plowe, Christopher V; Fairhurst, Rick M; Kwiatkowski, Dominic P

    2013-01-01

    We describe an analysis of genome variation in 825 Plasmodium falciparum samples from Asia and Africa that reveals an unusual pattern of parasite population structure at the epicentre of artemisinin resistance in western Cambodia. Within this relatively small geographical area we have discovered several distinct but apparently sympatric parasite subpopulations with extremely high levels of genetic differentiation. Of particular interest are three subpopulations, all associated with clinical resistance to artemisinin, which have skewed allele frequency spectra and remarkably high levels of haplotype homozygosity, indicative of founder effects and recent population expansion. We provide a catalogue of SNPs that show high levels of differentiation in the artemisinin-resistant subpopulations, including codon variants in various transporter proteins and DNA mismatch repair proteins. These data provide a population genetic framework for investigating the biological origins of artemisinin resistance and for defining molecular markers to assist its elimination. PMID:23624527

  17. The mechanism of resistance to sulfa drugs in Plasmodium falciparum.

    PubMed

    Triglia, Tony; Cowman, Alan F.

    1999-02-01

    The sulfonamide and sulfone (sulfa) group of antimalarials has been used extensively throughout malaria endemic regions of the world to control this important infectious disease of humans. Sulfadoxine is the most extensively used drug of this group of drugs and is usually combined with pyrimethamine (Fansidar), particularly for the control of Plasmodium falciparum, the causative agent of the most lethal form of malaria. Resistance to the sulfadoxine/pyrimethamine combination is widespread. Analysis using molecular, genetic and biochemical approaches has shown that the mechanism of resistance to sulfadoxine involves mutation of dihydropteroate synthase, the enzyme target of this group of drugs. Understanding the mechanism of resistance of P. falciparum to sulfa drugs has allowed detailed analysis of the epidemiology of the spread of drug resistance alleles in the field(1)and, in the future, opens the way to the development of novel antimalarials to this target enzyme. Copyright 1999 Harcourt Publishers Ltd.

  18. A genetic system to study Plasmodium falciparum protein function.

    PubMed

    Birnbaum, Jakob; Flemming, Sven; Reichard, Nick; Soares, Alexandra Blancke; Mesén-Ramírez, Paolo; Jonscher, Ernst; Bergmann, Bärbel; Spielmann, Tobias

    2017-03-13

    Current systems to study essential genes in the human malaria parasite Plasmodium falciparum are often inefficient and time intensive, and they depend on the genetic modification of the target locus, a process hindered by the low frequency of integration of episomal DNA into the genome. Here, we introduce a method, termed selection-linked integration (SLI), to rapidly select for genomic integration. SLI allowed us to functionally analyze targets at the gene and protein levels, thus permitting mislocalization of native proteins, a strategy known as knock sideways, floxing to induce diCre-based excision of genes and knocking in altered gene copies. We demonstrated the power and robustness of this approach by validating it for more than 12 targets, including eight essential ones. We also localized and inducibly inactivated Kelch13, the protein associated with artemisinin resistance. We expect this system to be widely applicable for P. falciparum and other organisms with limited genetic tractability.

  19. Characterization of the 26S proteasome network in Plasmodium falciparum.

    PubMed

    Wang, Lihui; Delahunty, Claire; Fritz-Wolf, Karin; Rahlfs, Stefan; Helena Prieto, Judith; Yates, John R; Becker, Katja

    2015-12-07

    In eukaryotic cells, the ubiquitin-proteasome system as a key regulator of protein quality control is an excellent drug target. We therefore aimed to analyze the 26S proteasome complex in the malaria parasite Plasmodium falciparum, which still threatens almost half of the world's population. First, we established an affinity purification protocol allowing for the isolation of functional 26S proteasome complexes from the parasite. Subunit composition of the proteasome and component stoichiometry were studied and physiologic interacting partners were identified via in situ protein crosslinking. Furthermore, intrinsic ubiquitin receptors of the plasmodial proteasome were determined and their roles in proteasomal substrate recognition were analyzed. Notably, PfUSP14 was characterized as a proteasome-associated deubiquitinase resulting in the concept that targeting proteasomal deubiquitinating activity in P. falciparum may represent a promising antimalarial strategy. The data provide insights into a profound network orchestrated by the plasmodial proteasome and identified novel drug target candidates in the ubiquitin-proteasome system.

  20. Costs and Cost-Effectiveness of Plasmodium vivax Control

    PubMed Central

    White, Michael T.; Yeung, Shunmay; Patouillard, Edith; Cibulskis, Richard

    2016-01-01

    The continued success of efforts to reduce the global malaria burden will require sustained funding for interventions specifically targeting Plasmodium vivax. The optimal use of limited financial resources necessitates cost and cost-effectiveness analyses of strategies for diagnosing and treating P. vivax and vector control tools. Herein, we review the existing published evidence on the costs and cost-effectiveness of interventions for controlling P. vivax, identifying nine studies focused on diagnosis and treatment and seven studies focused on vector control. Although many of the results from the much more extensive P. falciparum literature can be applied to P. vivax, it is not always possible to extrapolate results from P. falciparum–specific cost-effectiveness analyses. Notably, there is a need for additional studies to evaluate the potential cost-effectiveness of radical cure with primaquine for the prevention of P. vivax relapses with glucose-6-phosphate dehydrogenase testing. PMID:28025283

  1. Cryo scanning electron microscopy of Plasmodium falciparum-infected erythrocytes.

    PubMed

    Hempel, Casper

    2017-07-01

    Plasmodium falciparum invades erythrocytes as an essential part of their life cycle. While living inside erythrocytes, the parasite remodels the cell's intracellular organization as well as its outer surface. Late trophozoite-stage parasites and schizonts introduce numerous small protrusions on the erythrocyte surface, called knobs. Current methods for studying these knobs include atomic force microscopy and electron microscopy. Standard electron microscopy methods rely on chemical fixation and dehydration modifying cell size. Here, a novel method is presented using rapid freezing and scanning electron microscopy under cryogenic conditions allowing for high resolution and magnification of erythrocytes. This novel technique can be used for precise estimates of knob density and for studies on cytoadhesion. © 2017 APMIS. Published by John Wiley & Sons Ltd.

  2. Plasmodium falciparum Rab1A Localizes to Rhoptries in Schizonts

    PubMed Central

    Morse, David; Webster, Wesley; Kalanon, Ming; Langsley, Gordon; McFadden, Geoffrey I.

    2016-01-01

    Over-expression of a GFP-PfRab1A fusion protein in Plasmodium falciparum schizonts produces a punctate pattern of fluorescence typical of rhoptries, secretory organelles involved in host cell invasion. The GFP-positive bodies were purified by a combination of differential and density gradient centrifugation and their protein content determined by MS/MS sequencing. Consistent with the GFP rhoptry-like pattern of transgenic parasites, four of the 19 proteins identified have been previously described to be rhoptry-associated and another four are ER or ER-associated proteins. Confirmation that GFP-PfRab1A decorates rhoptries was obtained by its co-localization with Rap1 and Ron4 in late phase schizonts. We conclude that PfRab1A potentially regulates vesicular traffic from the endoplasmic reticulum to the rhoptries in Apicomplexa parasites. PMID:27348424

  3. Minireview: Invasive fungal infection complicating acute Plasmodium falciparum malaria.

    PubMed

    Däbritz, Jan; Schneider, Markward; Just-Nuebling, Gudrun; Groll, Andreas H

    2011-07-01

    Malaria is the most important parasitic infection in people, affecting 5-10% of the world's population with more than two million deaths a year. Whereas invasive bacterial infections are not uncommon during severe Plasmodium falciparum malaria, only a few cases of opportunistic fungal infections have been reported. Here, we present a fatal case of disseminated hyalohyphomycosis associated with acute P. falciparum malaria in a non-immune traveller, review the cases reported in the literature and discuss the theoretical foundations for the increased susceptibility of non-immune individuals with severe P. falciparum malaria to opportunistic fungal infections. Apart from the availability of free iron as sequelae of massive haemolysis, tissue damage, acidosis and measures of advanced life support, patients with complicated P. falciparum malaria also are profoundly immunosuppressed by the organism's interaction with innate and adaptive host immune mechanisms.

  4. Multiple independent introductions of Plasmodium falciparum in South America

    PubMed Central

    Yalcindag, Erhan; Elguero, Eric; Arnathau, Céline; Durand, Patrick; Akiana, Jean; Anderson, Timothy J.; Aubouy, Agnes; Balloux, François; Besnard, Patrick; Bogreau, Hervé; Carnevale, Pierre; D'Alessandro, Umberto; Fontenille, Didier; Gamboa, Dionicia; Jombart, Thibaut; Le Mire, Jacques; Leroy, Eric; Maestre, Amanda; Mayxay, Mayfong; Ménard, Didier; Musset, Lise; Newton, Paul N.; Nkoghé, Dieudonné; Noya, Oscar; Ollomo, Benjamin; Rogier, Christophe; Veron, Vincent; Wide, Albina; Zakeri, Sedigheh; Carme, Bernard; Legrand, Eric; Chevillon, Christine; Ayala, Francisco J.; Renaud, François; Prugnolle, Franck

    2012-01-01

    The origin of Plasmodium falciparum in South America is controversial. Some studies suggest a recent introduction during the European colonizations and the transatlantic slave trade. Other evidence—archeological and genetic—suggests a much older origin. We collected and analyzed P. falciparum isolates from different regions of the world, encompassing the distribution range of the parasite, including populations from sub-Saharan Africa, the Middle East, Southeast Asia, and South America. Analyses of microsatellite and SNP polymorphisms show that the populations of P. falciparum in South America are subdivided in two main genetic clusters (northern and southern). Phylogenetic analyses, as well as Approximate Bayesian Computation methods suggest independent introductions of the two clusters from African sources. Our estimates of divergence time between the South American populations and their likely sources favor a likely introduction from Africa during the transatlantic slave trade. PMID:22203975

  5. Spontaneous Subdural Haemorrhage: A Rare Association with Plasmodium Vivax Malaria

    PubMed Central

    Hariprasad, Shetty; Koya, Rohini; Acharya, Vasudev; Krishna, Shastry Barkur Anantha

    2016-01-01

    Malaria is an endemic disease in tropical countries and disease of universal importance. Central Nervous System (CNS) complications of malaria are severe and associated with significant mortality. Thrombocytopaenia in malaria causing haemorrhagic CNS complications is rare. We report a case of 35-year-old male patient presented with headache, vomiting and was diagnosed to have subdural haemorrhage (SDH). On examination patient was found to be febrile with peripheral smear showing evidence of Plasmodium vivax (P.vivax) infection with severe thrombocytopaenia. In endemic regions with malaria, SDH being rare presentation of malaria should be considered as a differential diagnosis in febrile patients with neurological manifestations. Rarity of spontaneous SDH in malaria and raising awareness amongst treating physicians about the same is the driving factor for reporting this case. PMID:26894111

  6. Plasmodium falciparum In Vitro Resistance to Monodesethylamodiaquine, Dakar, Senegal, 2014

    PubMed Central

    Fall, Bécaye; Madamet, Marylin; Camara, Cheikhou; Amalvict, Rémy; Fall, Mansour; Nakoulima, Aminata; Diatta, Bakary; Diémé, Yaya; Wade, Boubacar

    2016-01-01

    We successfully cultured 36 Plasmodium falciparum isolates from blood samples of 44 malaria patients admitted to the Hôpital Principal de Dakar (Dakar, Senegal) during August–December 2014. The prevalence of isolates with in vitro reduced susceptibility was 30.6% for monodesethylamodiaquine, 52.8% for chloroquine, 44.1% for mefloquine, 16.7% for doxycycline, 11.8% for piperaquine, 8.3% for artesunate, 5.9% for pyronaridine, 2.8% for quinine and dihydroartemisinin, and 0.0% for lumefantrine. The prevalence of isolates with reduced in vitro susceptibility to the artemisinin-based combination therapy partner monodesethylamodiaquine increased from 5.6% in 2013 to 30.6% in 2014. Because of the increased prevalence of P. falciparum parasites with impaired in vitro susceptibility to monodesethylamodiaquine, the implementation of in vitro and in vivo surveillance of all artemisinin-based combination therapy partners is warranted. PMID:27088703

  7. Epidemiology of Plasmodium relictum infection in the house sparrow.

    PubMed

    Bichet, Coraline; Sorci, Gabriele; Robert, Alexandre; Julliard, Romain; Lendvai, Adám Z; Chastel, Olivier; Garnier, Stephane; Loiseau, Claire

    2014-02-01

    In vertebrates, multiple host characteristics and environmental factors are known to influence infectious disease dynamics. Here, we investigated variability in prevalence and parasitemia of Plasmodium relictum in the house sparrow ( Passer domesticus ) across a large number of rural and urban populations (n = 16). We found that prevalence was not predicted by any of the host traits investigated (age, sex, body mass, or wing length). However, parasitemia was significantly higher in females when compared to males and in 1-yr-olds as compared to older individuals. Neither prevalence nor parasitemia differed according to habitat type (urban vs. rural). These results suggest that inter-population variation in parasitemia depends on host intrinsic factors whereas variation in prevalence could be due to environmental differences between populations, such as climatic variables that might affect the abundance of vectors. This large-scale study gives us a better understanding of the key factors involved in the epidemiology of avian malaria.

  8. On Programmed Cell Death in Plasmodium falciparum: Status Quo

    PubMed Central

    Engelbrecht, Dewaldt; Durand, Pierre Marcel; Coetzer, Thérèsa Louise

    2012-01-01

    Conflicting arguments and results exist regarding the occurrence and phenotype of programmed cell death (PCD) in the malaria parasite Plasmodium falciparum. Inconsistencies relate mainly to the number and type of PCD markers assessed and the different methodologies used in the studies. In this paper, we provide a comprehensive overview of the current state of knowledge and empirical evidence for PCD in the intraerythrocytic stages of P. falciparum. We consider possible reasons for discrepancies in the data and offer suggestions towards more standardised investigation methods in this field. Furthermore, we present genomic evidence for PCD machinery in P. falciparum. We discuss the potential adaptive or nonadaptive role of PCD in the parasite life cycle and its possible exploitation in the development of novel drug targets. Lastly, we pose pertinent unanswered questions concerning the PCD phenomenon in P. falciparum to provide future direction. PMID:22287973

  9. Tafenoquine for the treatment of recurrent Plasmodium vivax malaria.

    PubMed

    Kitchener, Scott; Nasveld, Peter; Edstein, Michael D

    2007-03-01

    Tafenoquine was used to treat Plasmodium vivax malaria cases who had previously failed treatment with chloroquine and primaquine. Chloroquine was followed by a loading dose of tafenoquine (200 mg base/day for 3 days) and 200 mg a week was given for 8 weeks. One of 27 treated patients relapsed after 6 months of observation. A standard course of chloroquine administered with 8 weeks of tafenoquine may be more effective than chloroquine with primaquine (22.5 mg/day for 14 days) in preventing additional P. vivax relapses. Larger studies are required to optimize the combination, but our findings suggest that an extended use of tafenoquine may be required to prevent relapses of primaquine-tolerant strains of P. vivax malaria.

  10. Modeling Metabolism and Stage-Specific Growth of Plasmodium falciparum HB3 during the Intraerythrocytic Development Cycle

    DTIC Science & Technology

    2014-01-01

    Wallqvist The human malaria parasite Plasmodium falciparum goes through a complex life cycle, including a roughly 48-hour-long intraerythrocytic...disease warrant basic research into the different mechanisms used by Plasmodium falciparum , the most virulent causative agent of malaria , to survive and...metabolism and stage-specific growth of Plasmodium falciparum HB3 during the intraerythrocytic developmental cycle† Xin Fang, Jaques Reifman* and Anders

  11. Determinants of relapse periodicity in Plasmodium vivax malaria

    PubMed Central

    2011-01-01

    Plasmodium vivax is a major cause of febrile illness in endemic areas of Asia, Central and South America, and the horn of Africa. Plasmodium vivax infections are characterized by relapses of malaria arising from persistent liver stages of the parasite (hypnozoites) which can be prevented only by 8-aminoquinoline anti-malarials. Tropical P. vivax relapses at three week intervals if rapidly eliminated anti-malarials are given for treatment, whereas in temperate regions and parts of the sub-tropics P. vivax infections are characterized either by a long incubation or a long-latency period between illness and relapse - in both cases approximating 8-10 months. The epidemiology of the different relapse phenotypes has not been defined adequately despite obvious relevance to malaria control and elimination. The number of sporozoites inoculated by the anopheline mosquito is an important determinant of both the timing and the number of relapses. The intervals between relapses display a remarkable periodicity which has not been explained. Evidence is presented that the proportion of patients who have successive relapses is relatively constant and that the factor which activates hypnozoites and leads to regular interval relapse in vivax malaria is the systemic febrile illness itself. It is proposed that in endemic areas a large proportion of the population harbours latent hypnozoites which can be activated by a systemic illness such as vivax or falciparum malaria. This explains the high rates of vivax following falciparum malaria, the high proportion of heterologous genotypes in relapses, the higher rates of relapse in people living in endemic areas compared with artificial infection studies, and, by facilitating recombination between different genotypes, contributes to P. vivax genetic diversity particularly in low transmission settings. Long-latency P. vivax phenotypes may be more widespread and more prevalent than currently thought. These observations have important

  12. Antimalarial Benzoxaboroles Target Plasmodium falciparum Leucyl-tRNA Synthetase

    PubMed Central

    Sonoiki, Ebere; Palencia, Andres; Guo, Denghui; Ahyong, Vida; Dong, Chen; Li, Xianfeng; Hernandez, Vincent S.; Zhang, Yong-Kang; Choi, Wai; Gut, Jiri; Legac, Jennifer; Cooper, Roland; Alley, M. R. K.; Freund, Yvonne R.; DeRisi, Joseph; Cusack, Stephen

    2016-01-01

    There is a need for new antimalarials, ideally with novel mechanisms of action. Benzoxaboroles have been shown to be active against bacteria, fungi, and trypanosomes. Therefore, we investigated the antimalarial activity and mechanism of action of 3-aminomethyl benzoxaboroles against Plasmodium falciparum. Two 3-aminomethyl compounds, AN6426 and AN8432, demonstrated good potency against cultured multidrug-resistant (W2 strain) P. falciparum (50% inhibitory concentration [IC50] of 310 nM and 490 nM, respectively) and efficacy against murine Plasmodium berghei infection when administered orally once daily for 4 days (90% effective dose [ED90], 7.4 and 16.2 mg/kg of body weight, respectively). To characterize mechanisms of action, we selected parasites with decreased drug sensitivity by culturing with stepwise increases in concentration of AN6426. Resistant clones were characterized by whole-genome sequencing. Three generations of resistant parasites had polymorphisms in the predicted editing domain of the gene encoding a P. falciparum leucyl-tRNA synthetase (LeuRS; PF3D7_0622800) and in another gene (PF3D7_1218100), which encodes a protein of unknown function. Solution of the structure of the P. falciparum LeuRS editing domain suggested key roles for mutated residues in LeuRS editing. Short incubations with AN6426 and AN8432, unlike artemisinin, caused dose-dependent inhibition of [14C]leucine incorporation by cultured wild-type, but not resistant, parasites. The growth of resistant, but not wild-type, parasites was impaired in the presence of the unnatural amino acid norvaline, consistent with a loss of LeuRS editing activity in resistant parasites. In summary, the benzoxaboroles AN6426 and AN8432 offer effective antimalarial activity and act, at least in part, against a novel target, the editing domain of P. falciparum LeuRS. PMID:27270277

  13. Alternative Protein Secretion in the Malaria Parasite Plasmodium falciparum

    PubMed Central

    Thavayogarajah, Thuvaraka; Gangopadhyay, Preetish; Rahlfs, Stefan; Becker, Katja; Lingelbach, Klaus; Przyborski, Jude M.; Holder, Anthony A.

    2015-01-01

    Plasmodium falciparum invades human red blood cells, residing in a parasitophorous vacuole (PV), with a parasitophorous vacuole membrane (PVM) separating the PV from the host cell cytoplasm. Here we have investigated the role of N-myristoylation and two other N-terminal motifs, a cysteine potential S-palmitoylation site and a stretch of basic residues, as the driving force for protein targeting to the parasite plasma membrane (PPM) and subsequent translocation across this membrane. Plasmodium falciparum adenylate kinase 2 (Pf AK2) contains these three motifs, and was previously proposed to be targeted beyond the parasite to the PVM, despite the absence of a signal peptide for entry into the classical secretory pathway. Biochemical and microscopy analyses of PfAK2 variants tagged with green fluorescent protein (GFP) showed that these three motifs are involved in targeting the protein to the PPM and translocation across the PPM to the PV. It was shown that the N-terminal 37 amino acids of PfAK2 alone are sufficient to target and translocate GFP across the PPM. As a control we examined the N-myristoylated P. falciparum ADP-ribosylation factor 1 (PfARF1). PfARF1 was found to co-localise with a Golgi marker. To determine whether or not the putative palmitoylation and the cluster of lysine residues from the N-terminus of PfAK2 would modulate the subcellular localization of PfARF1, a chimeric fusion protein containing the N-terminus of PfARF1 and the two additional PfAK2 motifs was analysed. This chimeric protein was targeted to the PPM, but not translocated across the membrane into the PV, indicating that other features of the N-terminus of PfAK2 also play a role in the secretion process. PMID:25909331

  14. Augmented plasma microparticles during acute Plasmodium vivax infection

    PubMed Central

    2010-01-01

    Background In the last few years, the study of microparticles (MPs) - submicron vesicles released from cells upon activation or apoptosis - has gained growing interest in the field of inflammation and in infectious diseases. Their role in the human malaria parasite Plasmodium vivax remains unexplored. Because acute vivax malaria has been related to pro-inflammatory responses, the main hypothesis investigated in this study was that Plasmodium vivax infection is associated with elevated levels of circulating MPs, which may play a role during acute disease in non-immune patients. Methods Plasma MPs were analysed among thirty-seven uncomplicated P. vivax infections from an area of unstable malaria transmission in the Brazilian Amazon. The MP phenotype was analysed by flow cytometry using the classical MP marker, annexin, and fluorochrome-labeled monoclonal antibodies against specific cell surface markers. The frequencies of plasma MPs in P. vivax patients (n = 37) were further compared to malaria-unexposed controls (n = 15) and ovarian carcinoma patients (n = 12), a known MPs-inducing disease non-related to malaria. Results The frequencies of plasma circulating MPs were markedly increased in P. vivax patients, as compared to healthy age-matched malaria-unexposed controls. Although platelets, erythrocytes and leukocytes were the main cellular sources of MPs during vivax malaria, platelet derived-MPs (PMPs) increased in a linear fashion with the presence of fever at the time of blood collection (β = 0.06, p < 0.0001) and length of acute symptoms (β = 0.36, p < 0.0001). Finally, the results suggest that plasma levels of PMPs diminish as patient experience more episodes of clinical malaria (β = 0.07, p < 0.003). Conclusions Abundant circulating MPs are present during acute P. vivax infection, and platelet derived-MPs may play a role on the acute inflammatory symptoms of malaria vivax. PMID:21080932

  15. Plasmodium infection alters Anopheles gambiae detoxification gene expression

    PubMed Central

    2010-01-01

    Background Anopheles gambiae has been shown to change its global gene expression patterns upon Plasmodium infection. While many alterations are directly related to the mosquito's innate immune response, parasite invasion is also expected to generate toxic by-products such as free radicals. The current study aimed at identifying which loci coding for detoxification enzymes are differentially expressed as a function of Plasmodium berghei infection in midgut and fat body tissues. Results Using a custom-made DNA microarray, transcript levels of 254 loci primarily belonging to three major detoxification enzyme families (glutathione S-transferases, cytochrome P450 monooxygenases and esterases) were compared in infected and uninfected mosquitoes both during ookinete invasion and the release of sporozoites into the hemocoel. The greatest changes in gene expression were observed in the midgut in response to ookinete invasion. Interestingly, many detoxification genes including a large number of P450s were down-regulated at this stage. In the fat body, while less dramatic, gene expression alterations were also observed and occurred during the ookinete invasion and during the release of sporozoites into the hemocoel. While most gene expression changes were tissue-related, CYP6M2, a CYP previously associated with insecticide resistance, was over-expressed both in the midgut and fat body during ookinete invasion. Conclusions Most toxicity-related reactions occur in the midgut shortly after the ingestion of an infected blood meal. Strong up-regulation of CYP6M2 in the midgut and the fat body as well as its previous association with insecticide resistance shows its broad role in metabolic detoxification. PMID:20482856

  16. Calmidazolium evokes high calcium fluctuations in Plasmodium falciparum.

    PubMed

    Budu, Alexandre; Gomes, Mayrim M; Melo, Pollyana M; El Chamy Maluf, Sarah; Bagnaresi, Piero; Azevedo, Mauro F; Carmona, Adriana K; Gazarini, Marcos L

    2016-03-01

    Calcium and calmodulin (CaM) are important players in eukaryote cell signaling. In the present study, by using a knockin approach, we demonstrated the expression and localization of CaM in all erythrocytic stages of Plasmodium falciparum. Under extracellular Ca(2+)-free conditions, calmidazolium (CZ), a potent CaM inhibitor, promoted a transient cytosolic calcium ([Ca(2+)]cyt) increase in isolated trophozoites, indicating that CZ mobilizes intracellular sources of calcium. In the same extracellular Ca(2+)-free conditions, the [Ca(2+)]cyt rise elicited by CZ treatment was ~3.5 fold higher when the endoplasmic reticulum (ER) calcium store was previously depleted ruling out the mobilization of calcium from the ER by CZ. The effects of the Ca(2+)/H(+) ionophore ionomycin (ION) and the Na(+)/H(+) ionophore monensin (MON) suggest that the [Ca(2+)]cyt-increasing effect of CZ is driven by the removal of Ca(2+) from at least one Ca(2+)-CaM-related (CaMR) protein as well as by the mobilization of Ca(2+) from intracellular acidic calcium stores. Moreover, we showed that the mitochondrion participates in the sequestration of the cytosolic Ca(2+) elicited by CZ. Finally, the modulation of membrane Ca(2+) channels by CZ and thapsigargin (THG) was demonstrated. The opened channels were blocked by the unspecific calcium channel blocker Co(2+) but not by 2-APB (capacitative calcium entry inhibitor) or nifedipine (L-type Ca(2+) channel inhibitor). Taken together, the results suggested that one CaMR protein is an important modulator of calcium signaling and homeostasis during the Plasmodium intraerythrocytic cell cycle, working as a relevant intracellular Ca(2+) reservoir in the parasite. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Plasmodium falciparum MLH is schizont stage specific endonuclease.

    PubMed

    Tarique, Mohammed; Satsangi, Akash Tripathi; Ahmad, Moaz; Singh, Shailja; Tuteja, Renu

    2012-02-01

    Malaria is one of the most important infectious diseases in many regions around the world including India. Plasmodium falciparum is the cause of most lethal form of malaria while Plasmodium vivax is the major cause outside Africa. Regardless of considerable efforts over the last many years there is still no commercial vaccine against malaria and the disease is mainly treated using a range of established drugs. With time, the malaria parasite is developing drug resistance to most of the commonly used drugs. This drug resistance might be due to defective mismatch repair in the parasite. Previously we have reported that the P. falciparum genome contains homologues to most of the components of mismatch repair (MMR) complex. In the present study we report the detailed biochemical characterization of one of the main component of MMR complex, MLH, from P. falciparum. Our results show that MLH is an ATPase and it can incise covalently closed circular DNA in the presence of Mn(2+) or Mg(2+) ions. Using the truncated derivatives we show that full length protein MLH is required for all the enzymatic activities. Using immunodepletion assays we further show that the ATPase and endomuclease activities are attributable to PfMLH protein. Using immunofluorescence assay we report that the peak expression of MLH in both 3D7 and Dd2 strains of P. falciparum is mainly in the schizont stages of the intraerythrocytic development, where DNA replication is active. MMR also contributes to the overall fidelity of DNA replication and the peak expression of MLH in the schizont stages suggests that MLH is most likely involved in correcting the mismatches occurring during replication. This study should make a significant contribution in our better understanding of DNA metabolic processes in the parasite.

  18. Antimalarial activity of Malaysian Plectranthus amboinicus against Plasmodium berghei

    PubMed Central

    Ramli, Norazsida; Ahamed, Pakeer Oothuman Syed; Elhady, Hassan Mohamed; Taher, Muhammad

    2014-01-01

    Context: Malaria is a mosquito-borne disease caused by parasitic protozoa from the genus of Plasmodium. The protozoans have developed resistance against many of current drugs. It is urgent to find an alternative source of new antimalarial agent. In the effort to discover new antimalarial agents, this research has been conducted on Plectranthus amboinicus. Aims: This study was conducted to evaluate the toxicity and antiplasmodial properties of P. amboinicus. Materials and Methods: Acute oral toxicity dose at 5000 mg/kg was conducted to evaluate the safety of this extract. Twenty mice were divided into control and experimental group. All the mice were observed for signs of toxicity, mortality, weight changes and histopathological changes. Antimalarial activity of different extract doses of 50, 200, 400 and 1000 mg/kg were tested in vivo against Plasmodium berghei infections in mice (five mice for each group) during early, established and residual infections. Results: The acute oral toxicity test revealed that no mortality or evidence of adverse effects was seen in the treated mice. The extract significantly reduced the parasitemia by the 50 (P = 0.000), 200 (P = 0.000) and 400 mg/kg doses (P = 0.000) in the in vivo prophylactic assay. The percentage chemo-suppression was calculated as 83.33% for 50 mg/kg dose, 75.62% for 200 mg/kg dose and 90.74% for 400 mg/kg dose. Body weight of all treated groups; T1, T2, T3 and T4 also showed enhancement after 7 days posttreatment. Statistically no reduction of parasitemia calculated for curative and suppressive test. Conclusion: Thus, this extract may give a promising agent to be used as a prophylactic agent of P. berghei infection. PMID:25276063

  19. The transcriptome of the intraerythrocytic developmental cycle of Plasmodium falciparum.

    PubMed

    Bozdech, Zbynek; Llinás, Manuel; Pulliam, Brian Lee; Wong, Edith D; Zhu, Jingchun; DeRisi, Joseph L

    2003-10-01

    Plasmodium falciparum is the causative agent of the most burdensome form of human malaria, affecting 200-300 million individuals per year worldwide. The recently sequenced genome of P. falciparum revealed over 5,400 genes, of which 60% encode proteins of unknown function. Insights into the biochemical function and regulation of these genes will provide the foundation for future drug and vaccine development efforts toward eradication of this disease. By analyzing the complete asexual intraerythrocytic developmental cycle (IDC) transcriptome of the HB3 strain of P. falciparum, we demonstrate that at least 60% of the genome is transcriptionally active during this stage. Our data demonstrate that this parasite has evolved an extremely specialized mode of transcriptional regulation that produces a continuous cascade of gene expression, beginning with genes corresponding to general cellular processes, such as protein synthesis, and ending with Plasmodium-specific functionalities, such as genes involved in erythrocyte invasion. The data reveal that genes contiguous along the chromosomes are rarely coregulated, while transcription from the plastid genome is highly coregulated and likely polycistronic. Comparative genomic hybridization between HB3 and the reference genome strain (3D7) was used to distinguish between genes not expressed during the IDC and genes not detected because of possible sequence variations. Genomic differences between these strains were found almost exclusively in the highly antigenic subtelomeric regions of chromosomes. The simple cascade of gene regulation that directs the asexual development of P. falciparum is unprecedented in eukaryotic biology. The transcriptome of the IDC resembles a "just-in-time" manufacturing process whereby induction of any given gene occurs once per cycle and only at a time when it is required. These data provide to our knowledge the first comprehensive view of the timing of transcription throughout the intraerythrocytic

  20. The Transcriptome of the Intraerythrocytic Developmental Cycle of Plasmodium falciparum

    PubMed Central

    Pulliam, Brian Lee; Wong, Edith D; Zhu, Jingchun

    2003-01-01

    Plasmodium falciparum is the causative agent of the most burdensome form of human malaria, affecting 200–300 million individuals per year worldwide. The recently sequenced genome of P. falciparum revealed over 5,400 genes, of which 60% encode proteins of unknown function. Insights into the biochemical function and regulation of these genes will provide the foundation for future drug and vaccine development efforts toward eradication of this disease. By analyzing the complete asexual intraerythrocytic developmental cycle (IDC) transcriptome of the HB3 strain of P. falciparum, we demonstrate that at least 60% of the genome is transcriptionally active during this stage. Our data demonstrate that this parasite has evolved an extremely specialized mode of transcriptional regulation that produces a continuous cascade of gene expression, beginning with genes corresponding to general cellular processes, such as protein synthesis, and ending with Plasmodium-specific functionalities, such as genes involved in erythrocyte invasion. The data reveal that genes contiguous along the chromosomes are rarely coregulated, while transcription from the plastid genome is highly coregulated and likely polycistronic. Comparative genomic hybridization between HB3 and the reference genome strain (3D7) was used to distinguish between genes not expressed during the IDC and genes not detected because of possible sequence variations. Genomic differences between these strains were found almost exclusively in the highly antigenic subtelomeric regions of chromosomes. The simple cascade of gene regulation that directs the asexual development of P. falciparum is unprecedented in eukaryotic biology. The transcriptome of the IDC resembles a “just-in-time” manufacturing process whereby induction of any given gene occurs once per cycle and only at a time when it is required. These data provide to our knowledge the first comprehensive view of the timing of transcription throughout the

  1. Identification of the erythrocyte binding domains of Plasmodium vivax and Plasmodium knowlesi proteins involved in erythrocyte invasion

    PubMed Central

    1994-01-01

    Plasmodium vivax and the related monkey malaria, P. knowlesi, require interaction with the Duffy blood group antigen, a receptor for a family of chemokines that includes interleukin 8, to invade human erythrocytes. One P. vivax and three P. knowlesi proteins that serve as erythrocyte binding ligands in such interactions share sequence homology. Expression of different regions of the P. vivax protein in COS7 cells identified a cysteine-rich domain that bound Duffy blood group-positive but not Duffy blood group-negative human erythrocytes. The homologous domain of the P. knowlesi proteins also bound erythrocytes, but had different specificities. The P. vivax and P. knowlesi binding domains lie in one of two regions of homology with the P. falciparum sialic acid binding protein, another erythrocyte binding ligand, indicating conservation of the domain for erythrocyte binding in evolutionarily distant malaria species. The binding domains of these malaria ligands represent potential vaccine candidates and targets for receptor-blockade therapy. PMID:8046329

  2. A molecular survey of acute febrile illnesses reveals Plasmodium vivax infections in Kedougou, southeastern Senegal.

    PubMed

    Niang, Makhtar; Thiam, Laty Gaye; Sow, Abdourahmane; Loucoubar, Cheikh; Bob, Ndeye Sakha; Diop, Fode; Diouf, Babacar; Niass, Oumy; Mansourou, Annick; Varela, Marie Louise; Perraut, Ronald; Sall, Amadou A; Toure-Balde, Aissatou

    2015-07-19

    Control efforts towards malaria due to Plasmodium falciparum significantly decreased the incidence of the disease in many endemic countries including Senegal. Surprisingly, in Kedougou (southeastern Senegal) P. falciparum malaria remains highly prevalent and the relative contribution of other Plasmodium species to the global malaria burden is very poorly documented, partly due to the low sensitivity of routine diagnostic tools. Molecular methods offer better estimate of circulating Plasmodium species in a given area. A molecular survey was carried out to document circulating malaria parasites in Kedougou region. A total of 263 long-term stored sera obtained from patients presenting with acute febrile illness in Kedougou between July 2009 and July 2013 were used for malaria parasite determination. Sera were withdrawn from a collection established as part of a surveillance programme of arboviruses infections in the region. Plasmodium species were characterized by a nested PCR-based approach targeting the 18S small sub-unit ribosomal RNA genes of Plasmodium spp. Of the 263 sera screened in this study, Plasmodium genomic DNA was amplifiable by nested PCR from 62.35% (164/263) of samples. P. falciparum accounted for the majority of infections either as single in 85.97% (141/164) of Plasmodium-positive samples or mixed with Plasmodium ovale (11.58%, 19/164) or Plasmodium vivax (1.21%, 2/164). All 19 (11.58%) P. ovale-infected patients were mixed with P. falciparum, while no Plasmodium malariae was detected in this survey. Four patients (2.43%) were found to be infected by P. vivax, two of whom were mixed with P. falciparum. P. vivax infections originated from Bandafassi and Ninefesha villages and concerned patients aged 4, 9, 10, and 15 years old, respectively. DNA sequences alignment and phylogenetic analysis demonstrated that sequences from Kedougou corresponded to P. vivax, therefore confirming the presence of P. vivax infections in Senegal. The results confirm the

  3. Spatial and space-time distribution of Plasmodium vivax and Plasmodium falciparum malaria in China, 2005-2014.

    PubMed

    Hundessa, Samuel H; Williams, Gail; Li, Shanshan; Guo, Jinpeng; Chen, Linping; Zhang, Wenyi; Guo, Yuming

    2016-12-19

    Despite the declining burden of malaria in China, the disease remains a significant public health problem with periodic outbreaks and spatial variation across the country. A better understanding of the spatial and temporal characteristics of malaria is essential for consolidating the disease control and elimination programme. This study aims to understand the spatial and spatiotemporal distribution of Plasmodium vivax and Plasmodium falciparum malaria in China during 2005-2009. Global Moran's I statistics was used to detect a spatial distribution of local P. falciparum and P. vivax malaria at the county level. Spatial and space-time scan statistics were applied to detect spatial and spatiotemporal clusters, respectively. Both P. vivax and P. falciparum malaria showed spatial autocorrelation. The most likely spatial cluster of P. vivax was detected in northern Anhui province between 2005 and 2009, and western Yunnan province between 2010 and 2014. For P. falciparum, the clusters included several counties of western Yunnan province from 2005 to 2011, Guangxi from 2012 to 2013, and Anhui in 2014. The most likely space-time clusters of P. vivax malaria and P. falciparum malaria were detected in northern Anhui province and western Yunnan province, respectively, during 2005-2009. The spatial and space-time cluster analysis identified high-risk areas and periods for both P. vivax and P. falciparum malaria. Both malaria types showed significant spatial and spatiotemporal variations. Contrary to P. vivax, the high-risk areas for P. falciparum malaria shifted from the west to the east of China. Further studies are required to examine the spatial changes in risk of malaria transmission and identify the underlying causes of elevated risk in the high-risk areas.

  4. Clustered local transmission and asymptomatic Plasmodium falciparum and Plasmodium vivax malaria infections in a recently emerged, hypoendemic Peruvian Amazon community

    PubMed Central

    Branch, OraLee; Casapia, W Martin; Gamboa, Dionicia V; Hernandez, Jean N; Alava, Freddy F; Roncal, Norma; Alvarez, Eugenia; Perez, Enrique J; Gotuzzo, Eduardo

    2005-01-01

    Background There is a low incidence of malaria in Iquitos, Peru, suburbs detected by passive case-detection. This low incidence might be attributable to infections clustered in some households/regions and/or undetected asymptomatic infections. Methods Passive case-detection (PCD) during the malaria season (February-July) and an active case-detection (ACD) community-wide survey (March) surveyed 1,907 persons. Each month, April-July, 100-metre at-risk zones were defined by location of Plasmodium falciparum infections in the previous month. Longitudinal ACD and PCD (ACP+PCD) occurred within at-risk zones, where 137 houses (573 persons) were randomly selected as sentinels, each with one month of weekly active sampling. Entomological captures were conducted in the sentinel houses. Results The PCD incidence was 0.03 P. falciparum and 0.22 Plasmodium vivax infections/person/malaria-season. However, the ACD+PCD prevalence was 0.13 and 0.39, respectively. One explanation for this 4.33 and 1.77-fold increase, respectively, was infection clustering within at-risk zones and contiguous households. Clustering makes PCD, generalized to the entire population, artificially low. Another attributable-factor was that only 41% and 24% of the P. falciparum and P. vivax infections were associated with fever and 80% of the asymptomatic infections had low-density or absent parasitaemias the following week. After accounting for asymptomatic infections, a 2.6-fold increase in ACD+PCD versus PCD was attributable to clustered transmission in at-risk zones. Conclusion Even in low transmission, there are frequent highly-clustered asymptomatic infections, making PCD an inadequate measure of incidence. These findings support a strategy of concentrating ACD and insecticide campaigns in houses adjacent to houses were malaria was detected one month prior. PMID:15975146

  5. Evaluation of a rapid whole blood immunochromatographic assay for the diagnosis of Plasmodium falciparum and Plasmodium vivax malaria.

    PubMed

    Fernando, S D; Karunaweera, N D; Fernando, W P

    2004-03-01

    Microscopic examination of blood smears is the 'gold standard' for malaria diagnosis, but is labour intensive and requires skilled operators. Plasmodium vivax malaria accounts for up to 70% of infections in Sri Lanka. The objective of this study was to determine the effectiveness of an immunochromatographic test which can detect both the species of Plasmodium, P. vivax and P. falciparum, present in Sri Lanka. Prospective study from May 2001 to March 2002. All persons above 5 years of age who presented to the Malaria Research Station, Kataragama or the Anti-malaria Clinic, Kurunegala, with a history of fever were recruited to the study. Thick and thin blood smears were examined for malarial parasites. The rapid diagnostic test (RDT), ICT Malaria P.f/P.v (AMRAD ICT, Australia) was performed simultaneously by an independent investigator. The severity of clinical disease of all patients was evaluated. The study sample comprised 328 individuals of whom 126 (38%) were infected, 102 with P. vivax (31.1%) and 24 with P. falciparum (7.3%). The RDT was found to be highly sensitive (100%) and specific (100%) for the diagnosis of P. falciparum when compared with field microscopy. The sensitivity for the diagnosis of P. vivax malaria was only 70%. When P. vivax parasitaemia was greater than 5000 parasites/microL the RDT was 96.2% sensitive. A significant association was noted between the band intensity on the dipstick and both peripheral blood parasitaemia (p < 0.001) and clinical severity of disease with P. vivax (p = 0.011). The ICT Malaria P.f/P.v test can be used in Sri Lanka in the absence of microscopists.

  6. New quinoline derivatives demonstrate a promising antimalarial activity against Plasmodium falciparum in vitro and Plasmodium berghei in vivo.

    PubMed

    Soares, Roberta Reis; da Silva, José Marcio Fernandes; Carlos, Bianca Cecheto; da Fonseca, Camila Campos; de Souza, Laila Salomé Araújo; Lopes, Fernanda Valério; de Paula Dias, Rafael Mafra; Moreira, Paulo Otávio Lourenço; Abramo, Clarice; Viana, Gustavo Henrique Ribeiro; de Pila Varotti, Fernando; da Silva, Adilson David; Scopel, Kézia Katiani Gorza

    2015-06-01

    Malaria continues to be an important public health problem in the world. Nowadays, the widespread parasite resistance to many drugs used in antimalarial therapy has made the effective treatment of cases and control of the disease a constant challenge. Therefore, the discovery of new molecules with good antimalarial activity and tolerance to human use can be really important in the further treatment of the disease. In this study we have investigated the antiplasmodial activity of 10 synthetic compounds derived from quinoline, five of them combined to sulfonamide and five to the hydrazine or hydrazide group. The compounds were evaluated according to their cytotoxicity against HepG2 and HeLa cell lines, their antimalarial activity against CQ-sensitive and CQ-resistant Plasmodium falciparum strains and, finally, their schizonticide blood action in mice infected with Plasmodium berghei NK65. The compounds exhibited no cytotoxic action in HepG2 and HeLa cell lines when tested up to a concentration of 100 μg/mL. In addition, the hydrazine or hydrazide derivative compounds were less cytotoxic against cell lines and more active against CQ-sensitive and CQ-resistant P. falciparum strains, showing high SI (>1000 when SI was calculated using the CC50 from the 3D7 strain as reference). When tested in vivo, the hydrazine derivative 1f compound showed activity against the development of blood parasites similar to that observed with CQ, the reference drug. Interestingly, the 1f compound demonstrated the best LipE value (4.84) among all those tested in vivo. Considering the in vitro and in vivo activities of the compounds studied here and the LipE values, we believe the 1f compound to be the most promising molecule for further studies in antimalarial chemotherapy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Morbidity and mortality associated with Plasmodium vivax and Plasmodium falciparum infection in a tertiary care kidney hospital.

    PubMed

    Imtiaz, Salman; Drohlia, Murtaza F; Nasir, Kiran; Hussain, Mehwish; Ahmad, Aasim

    2015-11-01

    Malaria is a disease of tropical regions and both types of plasmodia, i.e. Plasmodium falciparum and Plasmodium vivax, cause significant morbidity and mortality. P. vivax was thought to be benign and cause less morbidity and mortality. Many reports showed the devastating effect of vivax malaria too. We compared the clinical symptoms, laboratory markers, treatment and outcome of both the plasmodia. This is a retrospective analysis of 95 patients admitted to The Kidney Center, Karachi in a duration of 15 years (1997-2012); 45 patients with falciparum malaria and 50 patients with vivax malaria, and compared the clinical presentation, laboratory workup, treatment and outcome in both groups. The two groups constitute a mixed population of diabetes, chronic kidney disease (CKD) and hemodialysis patients. Both plasmodia have an equal clinical impact in terms of fever and rigors, anorexia, nausea, feeling of dyspnea, change in the mental status, changes in the urine color, diarrhea, volume depletion and pedal edema. However, patients with falciparum had significantly more vomiting (P = 0.02), oliguria (P = 0.003) and jaundice (P = 0.003). Laboratory parameters also showed a severe impact of falciparum, as there was more severe anemia and kidney and liver dysfunction. More patients were treated with dialysis and blood transfusion in the falciparum group. The outcome in the two groups was not significantly different in terms of death and days of hospitalization. Falciparum malaria has a higher clinical impact than the vivax malaria, but vivax is not as benign as it was once thought to be. It also has devastating effects on vulnerable populations like patients with CKD and diabetes.

  8. Plasmodium falciparum and Plasmodium vivax infections in the owl monkey (Aotus trivirgatus). I. The courses of untreated infections.

    PubMed

    Schmidt, L H

    1978-07-01

    This study, the first of three designed to determine the feasibility of using owl monkeys infected with human plasmodia in the search for new, more broadly active antimalarial drugs, dealt with the characteristics of untreated infections with eight strains of Plasmodium falciparum and two strains of P. vivax. Such infections, induced by standardized inocula of these strains in 1,733 monkeys, all Aotus trivirgatus griseimembra, were followed from day of inoculation to death of self-cure. The virulence of the various strains differed strikingly. Incidences of fatal reactions, ranging from 24.4--89.4% and 8.1--45.8%, respectively, in infections with strains of P. falciparum and P. vivax, were closely related to the rate at which parasitemia evolved, the height of parasitemia in the primary attack, and/or the time period over which a high parasite level was sustained. Antemortem symptom complexes and gross tissue and organ reactions in infections with P. falciparum varied with survival time, but within that boundary, were the same for infections with all eight strains of this plasmodium. Morbidity in both fatal and self-limited infections with both plasmodial species was related to height of parasitemia; however, at comparable parasite levels, symptoms exhibited in infections with P. vivax were more severe than in infections with P. falciparum. Overall, the characteristics of infections with these plasmodia in owl monkeys were remarkably similar to those of human infections. With respect to biological features, infections with P. falciparum and P. vivax in this simian host appear to have much to offer in the search for new antimalarial drugs.

  9. Hexaplex PCR Detection System for Identification of Five Human Plasmodium Species with an Internal Control

    PubMed Central

    Chew, Ching Hoong; Lim, Yvonne Ai Lian; Lee, Ping Chin; Mahmud, Rohela

    2012-01-01

    Malaria remains one of the major killers of humankind and persists to threaten the lives of more than one-third of the world's population. Given that human malaria can now be caused by five species of Plasmodium, i.e., Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, Plasmodium ovale, and the recently included Plasmodium knowlesi, there is a critical need not only to augment global health efforts in malaria control but also, more importantly, to develop a rapid, accurate, species-sensitive/species-specific, and economically effective diagnostic method for malaria caused by these five species. Therefore, in the present study, a straightforward single-step hexaplex PCR system targeting five human Plasmodium 18S small-subunit rRNAs (ssu rRNAs) was designed, and the system successfully detected all five human malaria parasites. In addition, this system enables the differentiation of single infection as well as mixed infections up to the two-species level. This assay was validated with 50 randomly blinded test and 184 clinical samples suspected to indicate malaria. This hexaplex PCR system is not only an ideal alternative for routine malaria diagnosis in laboratories with conventional PCR machines but also adds value to diagnoses when there is a lack of an experienced microscopist or/and when the parasite morphology is confusing. Indeed, this system will definitely enhance the accuracy and accelerate the speed in the diagnosis of malaria, as well as improve the efficacy of malaria treatment and control, in addition to providing reliable data from epidemiological surveillance studies. PMID:23035191

  10. Natural Plasmodium infections in Brazilian wild monkeys: reservoirs for human infections?

    PubMed

    Duarte, Ana Maria Ribeiro de Castro; Malafronte, Rosely dos Santos; Cerutti, Crispim; Curado, Izilda; de Paiva, Byanca Regina; Maeda, Adriana Yurika; Yamasaki, Tasciane; Summa, Maria Eugênia Laurito; Neves, Dafne do Valle Dutra de Andrade; de Oliveira, Salma Gomes; Gomes, Almério de Castro

    2008-08-01

    Four hundred and forty-eight samples of total blood from wild monkeys living in areas where human autochthonous malaria cases have been reported were screened for the presence of Plasmodium using microscopy and PCR analysis. Samples came from the following distinct ecological areas of Brazil: Atlantic forest (N=140), semideciduous Atlantic forest (N=257) and Cerrado (a savannah-like habitat) (N=51). Thick and thin blood smears of each specimen were examined and Plasmodium infection was screened by multiplex polymerase chain reaction (multiplex PCR). The frequency of Plasmodium infections detected by PCR in Alouatta guariba clamitans in the São Paulo Atlantic forest was 11.3% or 8/71 (5.6% for Plasmodium malariae and 5.6% for Plasmodium vivax) and one specimen was positive for Plasmodium falciparum (1.4%); Callithrix sp. (N=30) and Cebus apella (N=39) specimens were negative by PCR tests. Microscopy analysis was negative for all specimens from the Atlantic forest. The positivity rate for Alouatta caraya from semideciduous Atlantic forest was 6.8% (16/235) in the PCR tests (5.5, 0.8 and 0.4% for P. malariae, P. falciparum and P. vivax, respectively), while C. apella specimens were negative. Parasitological examination of the samples using thick smears revealed Plasmodium sp. infections in only seven specimens, which had few parasites (3.0%). Monkeys from the Cerrado (a savannah-like habitat) (42 specimens of A. caraya, 5 of Callithrix jacchus and 4 of C. apella) were negative in both tests. The parasitological prevalence of P. vivax and P. malariae in wild monkeys from Atlantic forest and semideciduous Atlantic forest and the finding of a positive result for P. falciparum in Alouatta from both types of forest support the hypothesis that monkeys belonging to this genus could be a potential reservoir. Furthermore, these findings raise the question of the relationship between simian and autochthonous human malaria in extra-Amazonian regions.

  11. Bacteria- and IMD Pathway-Independent Immune Defenses against Plasmodium falciparum in Anopheles gambiae

    PubMed Central

    Blumberg, Benjamin J.; Trop, Stefanie; Das, Suchismita; Dimopoulos, George

    2013-01-01

    The mosquito Anopheles gambiae uses its innate immune system to control bacterial and Plasmodium infection of its midgut tissue. The activation of potent IMD pathway-mediated anti-Plasmodium falciparum defenses is dependent on the presence of the midgut microbiota, which activate this defense system upon parasite infection through a peptidoglycan recognition protein, PGRPLC. We employed transcriptomic and reverse genetic analyses to compare the P. falciparum infection-responsive transcriptomes of septic and aseptic mosquitoes and to determine whether bacteria-independent anti-Plasmodium defenses exist. Antibiotic treated aseptic mosquitoes mounted molecular immune responses representing a variety of immune functions upon P. falciparum infection. Among other immune factors, our analysis uncovered a serine protease inhibitor (SRPN7) and Clip-domain serine protease (CLIPC2) that were transcriptionally induced in the midgut upon P. falciparum infection, independent of bacteria. We also showed that SRPN7 negatively and CLIPC2 positively regulate the anti-Plasmodium defense, independently of the midgut-associated bacteria. Co-silencing assays suggested that these two genes may function together in a signaling cascade. Neither gene was regulated, nor modulated, by infection with the rodent malaria parasite Plasmodium berghei, suggesting that SRPN7 and CLIPC2 are components of a defense system with preferential activity towards P. falciparum. Further analysis using RNA interference determined that these genes do not regulate the anti-Plasmodium defense mediated by the IMD pathway, and both factors act as agonists of the endogenous midgut microbiota, further demonstrating the lack of functional relatedness between these genes and the bacteria-dependent activation of the IMD pathway. This is the first study confirming the existence of a bacteria-independent, anti-P. falciparum defense. Further exploration of this anti-Plasmodium defense will help clarify determinants of

  12. Hexaplex PCR detection system for identification of five human Plasmodium species with an internal control.

    PubMed

    Chew, Ching Hoong; Lim, Yvonne Ai Lian; Lee, Ping Chin; Mahmud, Rohela; Chua, Kek Heng

    2012-12-01

    Malaria remains one of the major killers of humankind and persists to threaten the lives of more than one-third of the world's population. Given that human malaria can now be caused by five species of Plasmodium, i.e., Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, Plasmodium ovale, and the recently included Plasmodium knowlesi, there is a critical need not only to augment global health efforts in malaria control but also, more importantly, to develop a rapid, accurate, species-sensitive/species-specific, and economically effective diagnostic method for malaria caused by these five species. Therefore, in the present study, a straightforward single-step hexaplex PCR system targeting five human Plasmodium 18S small-subunit rRNAs (ssu rRNAs) was designed, and the system successfully detected all five human malaria parasites. In addition, this system enables the differentiation of single infection as well as mixed infections up to the two-species level. This assay was validated with 50 randomly blinded test and 184 clinical samples suspected to indicate malaria. This hexaplex PCR system is not only an ideal alternative for routine malaria diagnosis in laboratories with conventional PCR machines but also adds value to diagnoses when there is a lack of an experienced microscopist or/and when the parasite morphology is confusing. Indeed, this system will definitely enhance the accuracy and accelerate the speed in the diagnosis of malaria, as well as improve the efficacy of malaria treatment and control, in addition to providing reliable data from epidemiological surveillance studies.

  13. Distinct biochemical properties of human serine hydroxymethyltransferase compared with the Plasmodium enzyme: implications for selective inhibition.

    PubMed

    Pinthong, Chatchadaporn; Maenpuen, Somchart; Amornwatcharapong, Watcharee; Yuthavong, Yongyuth; Leartsakulpanich, Ubolsree; Chaiyen, Pimchai

    2014-06-01

    Serine hydroxymethyltransferase (SHMT) catalyzes the transfer of a hydroxymethyl group from l-serine to tetrahydrofolate to yield glycine and 5,10-methylenetetrahydrofolate. Our previous investigations have shown that SHMTs from Plasmodium spp. (P. falciparum, Pf; P. vivax, Pv) are different from the enzyme from rabbit liver in that Plasmodium SHMT can use d-serine as a substrate. In this report, the biochemical and biophysical properties of the Plasmodium and the human cytosolic form (hcSHMT) enzymes including ligand binding and kinetics were investigated. The data indicate that, similar to Plasmodium enzymes, hcSHMT can use d-serine as a substrate. However, hcSHMT displays many properties that are different from those of the Plasmodium enzymes. The molar absorption coefficient of hcSHMT-bound pyridoxal-5'-phosphate (PLP) is much greater than PvSHMT-bound or PfSHMT-bound PLP. The binding interactions of hcSHMT and Plasmodium SHMT with d-serine are different, as only the Plasmodium enzyme undergoes formation of a quinonoid-like species upon binding to d-serine. Furthermore, it has been noted that hcSHMT displays strong substrate inhibition by tetrahydrofolate (THF) (at THF > 40 μm), compared with SHMTs from Plasmodium and other species. The pH-activity profile of hcSHMT shows higher activities at lower pH values corresponding to a pKa value of 7.8 ± 0.1. Thiosemicarbazide reacts with hcSHMT following a one-step model [k1 of 12 ± 0.6 m(-1) ·s(-1) and k-1 of (1.0 ± 0.6) × 10(-3) s(-1) ], while the same reaction with PfSHMT involves at least three steps. All data indicated that the ligand binding environment of SHMT from human and Plasmodium are different, indicating that it should be possible to develop species-selective inhibitors in future studies. serine hydroxymethyltransferase, EC 2.1.2.1; 5,10-methylenetetrahydrofolate dehydrogenase, EC 1.5.1.5. © 2014 FEBS.

  14. Plasmodium falciparum Malaria Endemicity in Indonesia in 2010

    PubMed Central

    Elyazar, Iqbal R. F.; Gething, Peter W.; Patil, Anand P.; Rogayah, Hanifah; Kusriastuti, Rita; Wismarini, Desak M.; Tarmizi, Siti N.; Baird, J. Kevin; Hay, Simon I.

    2011-01-01

    Background Malaria control programs require a detailed understanding of the contemporary spatial distribution of infection risk to efficiently allocate resources. We used model based geostatistics (MBG) techniques to generate a contemporary map of Plasmodium falciparum malaria risk in Indonesia in 2010. Methods Plasmodium falciparum Annual Parasite Incidence (PfAPI) data (2006–2008) were used to map limits of P. falciparum transmission. A total of 2,581 community blood surveys of P. falciparum parasite rate (PfPR) were identified (1985–2009). After quality control, 2,516 were included into a national database of age-standardized 2–10 year old PfPR data (PfPR2–10) for endemicity mapping. A Bayesian MBG procedure was used to create a predicted surface of PfPR2–10 endemicity with uncertainty estimates. Population at risk estimates were derived with reference to a 2010 human population count surface. Results We estimate 132.8 million people in Indonesia, lived at risk of P. falciparum transmission in 2010. Of these, 70.3% inhabited areas of unstable transmission and 29.7% in stable transmission. Among those exposed to stable risk, the vast majority were at low risk (93.39%) with the reminder at intermediate (6.6%) and high risk (0.01%). More people in western Indonesia lived in unstable rather than stable transmission zones. In contrast, fewer people in eastern Indonesia lived in unstable versus stable transmission areas. Conclusion While further feasibility assessments will be required, the immediate prospects for sustained control are good across much of the archipelago and medium term plans to transition to the pre-elimination phase are not unrealistic for P. falciparum. Endemicity in areas of Papua will clearly present the greatest challenge. This P. falciparum endemicity map allows malaria control agencies and their partners to comprehensively assess the region-specific prospects for reaching pre-elimination, monitor and evaluate the effectiveness of

  15. Plasmodium falciparum malaria endemicity in Indonesia in 2010.

    PubMed

    Elyazar, Iqbal R F; Gething, Peter W; Patil, Anand P; Rogayah, Hanifah; Kusriastuti, Rita; Wismarini, Desak M; Tarmizi, Siti N; Baird, J Kevin; Hay, Simon I

    2011-01-01

    Malaria control programs require a detailed understanding of the contemporary spatial distribution of infection risk to efficiently allocate resources. We used model based geostatistics (MBG) techniques to generate a contemporary map of Plasmodium falciparum malaria risk in Indonesia in 2010. Plasmodium falciparum Annual Parasite Incidence (PfAPI) data (2006-2008) were used to map limits of P. falciparum transmission. A total of 2,581 community blood surveys of P. falciparum parasite rate (PfPR) were identified (1985-2009). After quality control, 2,516 were included into a national database of age-standardized 2-10 year old PfPR data (PfPR(2-10)) for endemicity mapping. A Bayesian MBG procedure was used to create a predicted surface of PfPR(2-10) endemicity with uncertainty estimates. Population at risk estimates were derived with reference to a 2010 human population count surface. We estimate 132.8 million people in Indonesia, lived at risk of P. falciparum transmission in 2010. Of these, 70.3% inhabited areas of unstable transmission and 29.7% in stable transmission. Among those exposed to stable risk, the vast majority were at low risk (93.39%) with the reminder at intermediate (6.6%) and high risk (0.01%). More people in western Indonesia lived in unstable rather than stable transmission zones. In contrast, fewer people in eastern Indonesia lived in unstable versus stable transmission areas. While further feasibility assessments will be required, the immediate prospects for sustained control are good across much of the archipelago and medium term plans to transition to the pre-elimination phase are not unrealistic for P. falciparum. Endemicity in areas of Papua will clearly present the greatest challenge. This P. falciparum endemicity map allows malaria control agencies and their partners to comprehensively assess the region-specific prospects for reaching pre-elimination, monitor and evaluate the effectiveness of future strategies against this 2010 baseline

  16. Biochemical and functional characterization of Plasmodium falciparum GTP cyclohydrolase I

    PubMed Central

    2014-01-01

    Background Antifolates are currently in clinical use for malaria preventive therapy and treatment. The drugs kill the parasites by targeting the enzymes in the de novo folate pathway. The use of antifolates has now been limited by the spread of drug-resistant mutations. GTP cyclohydrolase I (GCH1) is the first and the rate-limiting enzyme in the folate pathway. The amplification of the gch1 gene found in certain Plasmodium falciparum isolates can cause antifolate resistance and influence the course of antifolate resistance evolution. These findings showed the importance of P. falciparum GCH1 in drug resistance intervention. However, little is known about P. falciparum GCH1 in terms of kinetic parameters and functional assays, precluding the opportunity to obtain the key information on its catalytic reaction and to eventually develop this enzyme as a drug target. Methods Plasmodium falciparum GCH1 was cloned and expressed in bacteria. Enzymatic activity was determined by the measurement of fluorescent converted neopterin with assay validation by using mutant and GTP analogue. The genetic complementation study was performed in ∆folE bacteria to functionally identify the residues and domains of P. falciparum GCH1 required for its enzymatic activity. Plasmodial GCH1 sequences were aligned and structurally modeled to reveal conserved catalytic residues. Results Kinetic parameters and optimal conditions for enzymatic reactions were determined by the fluorescence-based assay. The inhibitor test against P. falciparum GCH1 is now possible as indicated by the inhibitory effect by 8-oxo-GTP. Genetic complementation was proven to be a convenient method to study the function of P. falciparum GCH1. A series of domain truncations revealed that the conserved core domain of GCH1 is responsible for its enzymatic activity. Homology modelling fits P. falciparum GCH1 into the classic Tunnelling-fold structure with well-conserved catalytic residues at the active site. Conclusions

  17. Ivermectin inhibits the sporogony of Plasmodium falciparum in Anopheles gambiae

    PubMed Central

    2012-01-01

    Background When ingested in a blood meal, ivermectin has been shown to reduce the survivorship of Anopheles gambiae in the laboratory and field. Furthermore, ivermectin mass drug administrations in Senegal have been shown to reduce the proportion of Plasmodium falciparum-sporozoite-containing An. gambiae. This study addresses whether ivermectin inhibits sporogony of P. falciparum in An. gambiae. Methods Anophele gambiae s.s. G3 strain were fed two concentrations of ivermectin (LC25 and LC5) along with P. falciparum NF54 in human blood meals at staggered intervals. Mosquitoes ingested ivermectin concurrent with parasites (DPI 0), or at three (DPI 3), six (DPI 6), and nine (DPI 9) days post parasite ingestion, or three days prior (DPI −3) to parasite ingestion. Mosquitoes were dissected at seven, twelve or fourteen days post parasite ingestion and either oocyst or sporozoite prevalence was recorded. To determine if P. falciparum sporozoite-containing An. gambiae were more susceptible to ivermectin than uninfected controls, survivorship was recorded for mosquitoes which ingested P. falciparum or control blood meal on DPI 0 and then a second blood meal containing ivermectin (LC25) on DPI 14. Results Ivermectin (LC25) co-ingested (DPI 0) with parasites reduced the proportion of An. gambiae that developed oocysts (χ2 = 15.4842, P = 0.0002) and sporozoites (χ2 = 19.9643, P < 0.0001). Ivermectin (LC25) ingested DPI 6 (χ2 = 8.5103, P = 0.0044) and 9 (χ2 = 14.7998, P < 0.0001) reduced the proportion of An. gambiae that developed sporozoites but not when ingested DPI 3 (χ2 = 0.0113, P = 1). Ivermectin (LC5) co-ingested (DPI 0) with parasites did not reduce the proportion of An. gambiae that developed oocysts (χ2 = 4.2518, P = 0.0577) or sporozoites (χ2 = 2.3636, P = 0.1540), however, when ingested DPI −3 the proportion of An. gambiae that developed sporozoites was reduced (χ2 = 8.4806, P = 0.0047). Plasmodium falciparum infection significantly reduced the

  18. The effects of urbanization on global Plasmodium vivax malaria transmission

    PubMed Central

    2012-01-01

    Background Many recent studies have examined the impact of urbanization on Plasmodium falciparum malaria endemicity and found a general trend of reduced transmission in urban areas. However, none has examined the effect of urbanization on Plasmodium vivax malaria, which is the most widely distributed malaria species and can also cause severe clinical syndromes in humans. In this study, a set of 10,003 community-based P. vivax parasite rate (PvPR) surveys are used to explore the relationships between PvPR in urban and rural settings. Methods The PvPR surveys were overlaid onto a map of global urban extents to derive an urban/rural assignment. The differences in PvPR values between urban and rural areas were then examined. Groups of PvPR surveys inside individual city extents (urban) and surrounding areas (rural) were identified to examine the local variations in PvPR values. Finally, the relationships of PvPR between urban and rural areas within the ranges of 41 dominant Anopheles vectors were examined. Results Significantly higher PvPR values in rural areas were found globally. The relationship was consistent at continental scales when focusing on Africa and Asia only, but in the Americas, significantly lower values of PvPR in rural areas were found, though the numbers of surveys were small. Moreover, except for the countries in the Americas, the same trends were found at national scales in African and Asian countries, with significantly lower values of PvPR in urban areas. However, the patterns at city scales among 20 specific cities where sufficient data were available were less clear, with seven cities having significantly lower PvPR values in urban areas and two cities showing significantly lower PvPR in rural areas. The urban–rural PvPR differences within the ranges of the dominant Anopheles vectors were generally, in agreement with the regional patterns found. Conclusions Except for the Americas, the patterns of significantly lower P. vivax transmission in

  19. Plasmodium P-Type Cyclin CYC3 Modulates Endomitotic Growth during Oocyst Development in Mosquitoes.

    PubMed

    Roques, Magali; Wall, Richard J; Douglass, Alexander P; Ramaprasad, Abhinay; Ferguson, David J P; Kaindama, Mbinda L; Brusini, Lorenzo; Joshi, Nimitray; Rchiad, Zineb; Brady, Declan; Guttery, David S; Wheatley, Sally P; Yamano, Hiroyuki; Holder, Anthony A; Pain, Arnab; Wickstead, Bill; Tewari, Rita

    2015-11-01

    Cell-cycle progression and cell division in eukaryotes are governed in part by the cyclin family and their regulation of cyclin-dependent kinases (CDKs). Cyclins are very well characterised in model systems such as yeast and human cells, but surprisingly little is known about their number and role in Plasmodium, the unicellular protozoan parasite that causes malaria. Malaria parasite cell division and proliferation differs from that of many eukaryotes. During its life cycle it undergoes two types of mitosis: endomitosis in asexual stages and an extremely rapid mitotic process during male gametogenesis. Both schizogony (producing merozoites) in host liver and red blood cells, and sporogony (producing sporozoites) in the mosquito vector, are endomitotic with repeated nuclear replication, without chromosome condensation, before cell division. The role of specific cyclins during Plasmodium cell proliferation was unknown. We show here that the Plasmodium genome contains only three cyclin genes, representing an unusual repertoire of cyclin classes. Expression and reverse genetic analyses of the single Plant (P)-type cyclin, CYC3, in the rodent malaria parasite, Plasmodium berghei, revealed a cytoplasmic and nuclear location of the GFP-tagged protein throughout the lifecycle. Deletion of cyc3 resulted in defects in size, number and growth of oocysts, with abnormalities in budding and sporozoite formation. Furthermore, global transcript analysis of the cyc3-deleted and wild type parasites at gametocyte and ookinete stages identified differentially expressed genes required for signalling, invasion and oocyst development. Collectively these data suggest that cyc3 modulates oocyst endomitotic development in Plasmodium berghei.

  20. Plasmodium species mixed infections in two areas of Manhiça District, Mozambique

    PubMed Central

    2005-01-01

    We compared the distribution patterns of individual Plasmodium species and mixed-species infections in two geographically close endemic areas, but showing environmental differences. Comparisons concerned circulating Plasmodium infections in both human and mosquito vector populations in the dry and wet seasons, at a micro-epidemiological level (households). Both areas revealed a very high overall prevalence of infection, all year-round and in all age groups. Plasmodium falciparum was the predominant species, being found in the vast majority of infected individuals regardless of the presence of other species. Plasmodium malariae and Plasmodium ovale occurred almost exclusively in mixed infections. Seasonal variation in P. malariae prevalence was observed in one area but not in the other. A decrease in P. malariae prevalence concurred with a marked increase of P. falciparum prevalence. However this was strongly dependent on age and when analysing infections at the individual level, a different pattern between co-infecting species was unveiled. Regarding transmission patterns, in both areas, P. falciparum gametocytes predominated in single infections regardless of age and P. malariae gametocyte carriage increased when its overall prevalence decreased. PMID:16094461

  1. PFE0565w, a Plasmodium falciparum Protein Expressed in Salivary Gland Sporozoites

    PubMed Central

    Schlarman, Maggie S.; Roberts, Renee N.; Kariuki, Michael M.; LaCrue, Alexis N.; Ou, Ruguang; Beerntsen, Brenda T.

    2012-01-01

    Because malaria is still a significant problem worldwide, additional control methods need to be developed. The Plasmodium sporozoite is a good target for control measures because it displays dual infectivity for both mosquito and vertebrate host tissues. The Plasmodium falciparum gene, PFE0565w, was chosen as a candidate for study based on data from PlasmoDB, the Plasmodium database, indicating that it is expressed both at the transcriptional and protein levels in sporozoites, likely encodes a putative surface protein, and may have a potential role in the invasion of host tissues. Additional sequence analysis shows that the PFE0565w protein has orthologs in other Plasmodium species, but none outside of the genus Plasmodium. PFE0565w expresses transcript during both the sporozoite and erythrocytic stages of the parasite life cycle, where an alternative transcript was discovered during the erythrocytic stages. Data show that transcript is not present during axenic exoerythrocytic stages. Despite transcript being present in several life cycle stages, the PFE0565w protein is present only during the salivary gland sporozoite stage. Because the PFE0565w protein is present in salivary gland sporozoites, it could be a novel candidate for a pre-erythrocytic stage vaccine. PMID:22665598

  2. Contribution of Plasmodium knowlesi to Multispecies Human Malaria Infections in North Sumatera, Indonesia.

    PubMed

    Lubis, Inke N D; Wijaya, Hendri; Lubis, Munar; Lubis, Chairuddin P; Divis, Paul C S; Beshir, Khalid B; Sutherland, Colin J

    2017-04-01

    As Indonesia works toward the goal of malaria elimination, information is lacking on malaria epidemiology from some western provinces. As a basis for studies of antimalarial efficacy, we set out to survey parasite carriage in 3 communities in North Sumatera Province. A combination of active and passive detection of infection was carried out among communities in Batubara, Langkat, and South Nias regencies. Finger-prick blood samples from consenting individuals of all ages provided blood films for microscopic examination and blood spots on filter paper. Plasmodium species were identified using nested polymerase chain reaction (PCR) of ribosomal RNA genes and a novel assay that amplifies a conserved sequence specific for the sicavar gene family of Plasmodium knowlesi. Of 3731 participants, 614 (16.5%) were positive for malaria parasites by microscopy. PCR detected parasite DNA in samples from 1169 individuals (31.3%). In total, 377 participants (11.8%) harbored P. knowlesi. Also present were Plasmodium vivax (14.3%), Plasmodium falciparum (10.5%) and Plasmodium malariae (3.4%). Amplification of sicavar is a specific and sensitive test for the presence of P. knowlesi DNA in humans. Subpatent and asymptomatic multispecies parasitemia is relatively common in North Sumatera, so PCR-based surveillance is required to support control and elimination activities.

  3. A rapid and scalable density gradient purification method for Plasmodium sporozoites

    PubMed Central

    2012-01-01

    Background Malaria remains a major human health problem, with no licensed vaccine currently available. Malaria infections initiate when infectious Plasmodium sporozoites are transmitted by Anopheline mosquitoes during their blood meal. Investigations of the malaria sporozoite are, therefore, of clear medical importance. However, sporozoites can only be produced in and isolated from mosquitoes, and their isolation results in large amounts of accompanying mosquito debris and contaminating microbes. Methods Here is described a discontinuous density gradient purification method for Plasmodium sporozoites that maintains parasite infectivity in vitro and in vivo and greatly reduces mosquito and microbial contaminants. Results This method provides clear advantages over previous approaches: it is rapid, requires no serum components, and can be scaled to purify >107 sporozoites with minimal operator involvement. Moreover, it can be effectively applied to both human (Plasmodium falciparum, Plasmodium vivax) and rodent (Plasmodium yoelii) infective species with excellent recovery rates. Conclusions This novel method effectively purifies viable malaria sporozoites by greatly reducing contaminating mosquito debris and microbial burdens associated with parasite isolation. Large-scale preparations of purified sporozoites will allow for enhanced in vitro infections, proteomics, and biochemical characterizations. In conjunction with aseptic mosquito rearing techniques, this purification technique will also support production of live attenuated sporozoites for vaccination. PMID:23244590

  4. Detection of Plasmodium in faeces of the New World primate Alouatta clamitans

    PubMed Central

    de Assis, Gabriela Maíra Pereira; de Alvarenga, Denise Anete Madureira; Costa, Daniela Camargos; de Souza, Júlio César; Hirano, Zelinda Maria Braga; Kano, Flora Satiko; de Sousa, Taís Nóbrega; de Brito, Cristiana Ferreira Alves

    2016-01-01

    Abstract Plasmodium falciparum and Plasmodium vivax have evolved with host switches between non-human primates (NHPs) and humans. Studies on the infection dynamics of Plasmodium species in NHPs will improve our understanding of the evolution of these parasites; however, such studies are hampered by the difficulty of handling animals in the field. The aim of this study was to detect genomic DNA of Plasmodium species from the faeces of New World monkeys. Faecal samples from 23 Alouatta clamitans from the Centre for Biological Research of Indaial (Santa Catarina, Brazil) were collected. Extracted DNA from faecal samples was used for molecular diagnosis of malaria by nested polymerase chain reaction. One natural infection with Plasmodium simium was identified by amplification of DNA extracted from the faeces of A. clamitans. Extracted DNA from a captive NHP was also used for parasite genotyping. The detection limit of the technique was evaluated in vitro using an artificial mixture of cultured P. falciparum in NHP faeces and determined to be 6.5 parasites/µL. Faecal samples of New World primates can be used to detect malaria infections in field surveys and also to monitor the genetic variability of parasites and dynamics of infection. PMID:27580347

  5. ZIPCO, a putative metal ion transporter, is crucial for Plasmodium liver-stage development.

    PubMed

    Sahu, Tejram; Boisson, Bertrand; Lacroix, Céline; Bischoff, Emmanuel; Richier, Quentin; Formaglio, Pauline; Thiberge, Sabine; Dobrescu, Irina; Ménard, Robert; Baldacci, Patricia

    2014-11-01

    The malaria parasite, Plasmodium, requires iron for growth, but how it imports iron remains unknown. We characterize here a protein that belongs to the ZIP (Zrt-, Irt-like Protein) family of metal ion transport proteins and have named ZIP domain-containing protein (ZIPCO). Inactivation of the ZIPCO-encoding gene in Plasmodium berghei, while not affecting the parasite's ability to multiply in mouse blood and to infect mosquitoes, greatly impairs its capacity to develop inside hepatocytes. Iron/zinc supplementation and depletion experiments suggest that ZIPCO is required for parasite utilization of iron and possibly zinc, consistent with its predicted function as a metal transporter. This is the first report of a ZIP protein having a crucial role in Plasmodium liver-stage development, as well as the first metal ion transporter identified in Plasmodium pre-erythrocytic stages. Because of the drastic dependence on iron of Plasmodium growth, ZIPCO and related proteins might constitute attractive drug targets to fight against malaria. © 2014 Institut Pasteur. Published under the terms of the CC BY 4.0 license.

  6. Susceptibility to Plasmodium liver stage infection is altered by hepatocyte polyploidy

    PubMed Central

    Austin, Laura S.; Kaushansky, Alexis; Kappe, Stefan H.I.

    2014-01-01

    Summary Plasmodium parasites infect hepatocytes of their mammalian hosts and within undergo obligate liver stage development. The specific host cell attributes that are important for liver infection remain largely unknown. Several host signaling pathways are perturbed in infected hepatocytes, some of which are important in the generation of hepatocyte polyploidy. To test the functional consequence of polyploidy in liver infection, we infected hepatocytes with the rodent malaria parasite Plasmodium yoelii both in vitro and in vivo and examined the ploidy of infected and uninfected hepatocytes by flow cytometry. In both hepatoma cell lines and in the mouse liver, the fraction of polyploid cells was higher in the infected cell population than in the uninfected cell population. When the data were reanalyzed by comparing the extent of Plasmodium infection within each ploidy subset, we found that infection rates were elevated in more highly polyploid cells and lower in diploid cells. Furthermore, we found that the parasite’s preference for host cells with high ploidy is conserved among rodent malaria species and the human malaria parasite Plasmodium falciparum. This parasite preference for host cells of high ploidy cannot be explained by differences in hepatocyte size or DNA replication. We conclude that Plasmodium preferentially infects and develops in polyploid hepatocytes. PMID:24612025

  7. An impossible journey? The development of Plasmodium falciparum NF54 in Culex quinquefasciatus.

    PubMed

    Knöckel, Julia; Molina-Cruz, Alvaro; Fischer, Elizabeth; Muratova, Olga; Haile, Ashley; Barillas-Mury, Carolina; Miller, Louis H

    2013-01-01

    Although Anopheles mosquitoes are the vectors for human Plasmodium spp., there are also other mosquito species-among them culicines (Culex spp., Aedes spp.)-present in malaria-endemic areas. Culicine mosquitoes transmit arboviruses and filarial worms to humans and are vectors for avian Plasmodium spp., but have never been observed to transmit human Plasmodium spp. When ingested by a culicine mosquito, parasites could either face an environment that does not allow development due to biologic incompatibility or be actively killed by the mosquito's immune system. In the latter case, the molecular mechanism of killing must be sufficiently powerful that Plasmodium is not able to overcome it. To investigate how human malaria parasites develop in culicine mosquitoes, we infected Culex quinquefasciatus with Plasmodium falciparum NF54 and monitored development of parasites in the blood bolus and midgut epithelium at different time points. Our results reveal that ookinetes develop in the midgut lumen of C. quinquefasciatus in slightly lower numbers than in Anopheles gambiae G3. After 30 hours, parasites have invaded the midgut and can be observed on the basal side of the midgut epithelium by confocal and transmission electron microscopy. Very few of the parasites in C. quinquefasciatus are alive, most of them are lysed. Eight days after the mosquito's blood meal, no oocysts can be found in C. quinquefasciatus. Our results suggest that the mosquito immune system could be involved in parasite killing early in development after ookinetes have crossed the midgut epithelium and come in contact with the mosquito hemolymph.

  8. Antibody-independent mechanisms regulate the establishment of chronic Plasmodium infection.

    PubMed

    Brugat, Thibaut; Reid, Adam James; Lin, Jing-Wen; Cunningham, Deirdre; Tumwine, Irene; Kushinga, Garikai; McLaughlin, Sarah; Spence, Philip; Böhme, Ulrike; Sanders, Mandy; Conteh, Solomon; Bushell, Ellen; Metcalf, Tom; Billker, Oliver; Duffy, Patrick E; Newbold, Chris; Berriman, Matthew; Langhorne, Jean

    2017-02-06

    Malaria is caused by parasites of the genus Plasmodium. All human-infecting Plasmodium species can establish long-lasting chronic infections(1-5), creating an infectious reservoir to sustain transmission(1,6). It is widely accepted that the maintenance of chronic infection involves evasion of adaptive immunity by antigenic variation(7). However, genes involved in this process have been identified in only two of five human-infecting species: Plasmodium falciparum and Plasmodium knowlesi. Furthermore, little is understood about the early events in the establishment of chronic infection in these species. Using a rodent model we demonstrate that from the infecting population, only a minority of parasites, expressing one of several clusters of virulence-associated pir genes, establishes a chronic infection. This process occurs in different species of parasites and in different hosts. Establishment of chronicity is independent of adaptive immunity and therefore different from the mechanism proposed for maintenance of chronic P. falciparum infections(7-9). Furthermore, we show that the proportions of parasites expressing different types of pir genes regulate the time taken to establish a chronic infection. Because pir genes are common to most, if not all, species of Plasmodium(10), this process may be a common way of regulating the establishment of chronic infections.

  9. Detection of Plasmodium in faeces of the New World primate Alouatta clamitans.

    PubMed

    Assis, Gabriela Maíra Pereira de; Alvarenga, Denise Anete Madureira de; Costa, Daniela Camargos; Souza, Júlio César de; Hirano, Zelinda Maria Braga; Kano, Flora Satiko; Sousa, Taís Nóbrega de; Brito, Cristiana Ferreira Alves de

    2016-09-01

    Plasmodium falciparum and Plasmodium vivax have evolved with host switches between non-human primates (NHPs) and humans. Studies on the infection dynamics of Plasmodium species in NHPs will improve our understanding of the evolution of these parasites; however, such studies are hampered by the difficulty of handling animals in the field. The aim of this study was to detect genomic DNA of Plasmodium species from the faeces of New World monkeys. Faecal samples from 23 Alouatta clamitans from the Centre for Biological Research of Indaial (Santa Catarina, Brazil) were collected. Extracted DNA from faecal samples was used for molecular diagnosis of malaria by nested polymerase chain reaction. One natural infection with Plasmodium simium was identified by amplification of DNA extracted from the faeces of A. clamitans. Extracted DNA from a captive NHP was also used for parasite genotyping. The detection limit of the technique was evaluated in vitro using an artificial mixture of cultured P. falciparum in NHP faeces and determined to be 6.5 parasites/µL. Faecal samples of New World primates can be used to detect malaria infections in field surveys and also to monitor the genetic variability of parasites and dynamics of infection.

  10. Detection of avian malaria (Plasmodium spp.) in native land birds of American Samoa

    USGS Publications Warehouse

    Jarvi, S.I.; Farias, M.E.M.; Baker, H.; Freifeld, H.B.; Baker, P.E.; Van Gelder, E.; Massey, J.G.; Atkinson, C.T.

    2003-01-01

    This study documents the presence of Plasmodium spp. in landbirds of central Polynesia. Blood samples collected from eight native and introduced species from the island of Tutuila, American Samoa were evaluated for the presence of Plasmodium spp. by nested rDNA PCR, serology and/or microscopy. A total of 111/188 birds (59%) screened by nested PCR were positive. Detection of Plasmodium spp. was verified by nucleotide sequence comparisons of partial 18S ribosomal RNA and TRAP (thrombospondin-related anonymous protein) genes using phylogenetic analyses. All samples screened by immunoblot to detect antibodies that cross-react with Hawaiian isolates of Plasmodium relictum (153) were negative. Lack of cross-reactivity is probably due to antigenic differences between the Hawaiian and Samoan Plasmodium isolates. Similarly, all samples examined by microscopy (214) were negative. The fact that malaria is present, but not detectable by blood smear evaluation is consistent with low peripheral parasitemia characteristic of chronic infections. High prevalence of apparently chronic infections, the relative stability of the native land bird communities, and the presence of mosquito vectors which are considered endemic and capable of transmitting avian Plasmodia, suggest that these parasites are indigenous to Samoa and have a long coevolutionary history with their hosts.

  11. Plasmodium prevalence across avian host species is positively associated with exposure to mosquito vectors.

    PubMed

    Medeiros, Matthew C I; Ricklefs, Robert E; Brawn, Jeffrey D; Hamer, Gabriel L

    2015-11-01

    The prevalence of vector-borne parasites varies greatly across host species, and this heterogeneity has been used to relate infectious disease susceptibility to host species traits. However, a few empirical studies have directly associated vector-borne parasite prevalence with exposure to vectors across hosts. Here, we use DNA sequencing of blood meals to estimate utilization of different avian host species by Culex mosquitoes, and relate utilization by these malaria vectors to avian Plasmodium prevalence. We found that avian host species that are highly utilized as hosts by avian malaria vectors are significantly more likely to have Plasmodium infections. However, the effect was not consistent among individual Plasmodium taxa. Exposure to vector bites may therefore influence the relative number of all avian Plasmodium infections among host species, while other processes, such as parasite competition and host-parasite coevolution, delimit the host distributions of individual Plasmodium species. We demonstrate that links between avian malaria susceptibility and host traits can be conditioned by patterns of exposure to vectors. Linking vector utilization rates to host traits may be a key area of future research to understand mechanisms that produce variation in the prevalence of vector-borne pathogens among host species.

  12. Host-cell sensors for Plasmodium activate innate immunity against liver-stage infection.

    PubMed

    Liehl, Peter; Zuzarte-Luís, Vanessa; Chan, Jennie; Zillinger, Thomas; Baptista, Fernanda; Carapau, Daniel; Konert, Madlen; Hanson, Kirsten K; Carret, Céline; Lassnig, Caroline; Müller, Mathias; Kalinke, Ulrich; Saeed, Mohsan; Chora, Angelo Ferreira; Golenbock, Douglas T; Strobl, Birgit; Prudêncio, Miguel; Coelho, Luis P; Kappe, Stefan H; Superti-Furga, Giulio; Pichlmair, Andreas; Vigário, Ana M; Rice, Charles M; Fitzgerald, Katherine A; Barchet, Winfried; Mota, Maria M

    2014-01-01

    Before they infect red blood cells and cause malaria, Plasmodium parasites undergo an obligate and clinically silent expansion phase in the liver that is supposedly undetected by the host. Here, we demonstrate the engagement of a type I interferon (IFN) response during Plasmodium replication in the liver. We identified Plasmodium RNA as a previously unrecognized pathogen-associated molecular pattern (PAMP) capable of activating a type I IFN response via the cytosolic pattern recognition receptor Mda5. This response, initiated by liver-resident cells through the adaptor molecule for cytosolic RNA sensors, Mavs, and the transcription factors Irf3 and Irf7, is propagated by hepatocytes in an interferon-α/β receptor-dependent manner. This signaling pathway is critical for immune cell-mediated host resistance to liver-stage Plasmodium infection, which we find can be primed with other PAMPs, including hepatitis C virus RNA. Together, our results show that the liver has sensor mechanisms for Plasmodium that mediate a functional antiparasite response driven by type I IFN.

  13. The evolution of genomic GC content undergoes a rapid reversal within the genus Plasmodium.

    PubMed

    Nikbakht, Hamid; Xia, Xuhua; Hickey, Donal A

    2014-09-01

    The genome of the malarial parasite Plasmodium falciparum is extremely AT rich. This bias toward a low GC content is a characteristic of several, but not all, species within the genus Plasmodium. We compared 4283 orthologous pairs of protein-coding sequences between Plasmodium falciparum and the less AT-biased Plasmodium vivax. Our results indicate that the common ancestor of these two species was also extremely AT rich. This means that, although there was a strong bias toward A+T during the early evolution of the ancestral Plasmodium lineage, there was a subsequent reversal of this trend during the more recent evolution of some species, such as P. vivax. Moreover, we show that not only is the P. vivax genome losing its AT richness, it is actually gaining a very significant degree of GC richness. This example illustrates the potential volatility of nucleotide content during the course of molecular evolution. Such reversible fluxes in nucleotide content within lineages could have important implications for phylogenetic reconstruction based on molecular sequence data.

  14. Invasion of erythrocytes in vitro by Plasmodium falciparum can be inhibited by monoclonal antibody directed against an S antigen.

    PubMed

    Saul, A; Cooper, J; Ingram, L; Anders, R F; Brown, G V

    1985-11-01

    A monoclonal antibody has been produced which binds to the heat stable S antigen present in the FCQ-27/PNG isolate of Plasmodium falciparum. This monoclonal antibody also inhibits the invasion in vitro of erythrocytes by malarial merozoites thus demonstrating that the S antigens of Plasmodium falciparum may be a target of protective immune responses.

  15. [The role of phosphoinositide-3-kinase in controlling the shape and directional movement in Physarum polycephalum plasmodium].

    PubMed

    Matveeva, N B; Beĭlina, S I; Teplov, V A

    2008-01-01

    The influence of wortmannin and LY294002, specific inhibitors of phosphoinosite-3-kinase, on the shape, motile behavior, and chemotaxis toward glucose has been investigated in Physarum polycephalum plasmodium, a multinuclear amoeboid cell with the autooscillatory mode of motion. Both inhibitors were shown to cause a reduction of the plasmodium frontal edge and a decrease in the efficiency of mass transfer during migration. They also suppress chemotaxis toward glucose and eliminate characteristic changes in autooscillatory behavior normally observed in response to the treatment of the whole plasmodium with glucose. The manifestation of these effects depends on the inhibitor concentration, the duration of treatment, and the size of plasmodium. The involvement of phosphoinosite-3-kinase in creating the frontal edge and in controlling the chemotaxis of Physarum plasmodium suggests that the interrelation of polar shape and directional movement of amoeboid cells with the distribution of phosphoinositides in the plasma membrane has the universal nature.

  16. Comparison of the antibody responses to Plasmodium vivax and Plasmodium falciparum antigens in residents of Mandalay, Myanmar

    PubMed Central

    2011-01-01

    Background The aim of this study was to investigate the profile of antibodies against several antigens of Plasmodium vivax and Plasmodium falciparum in Mandalay, Myanmar. Methods Malaria parasites were identified by microscopic examination. To test the antibodies against P. vivax and P. falciparum in sera, an indirect immunofluorescence antibody test (IFAT) was performed using asexual blood parasite antigens. An enzyme-linked immunosorbent assay (ELISA) was performed with circumsporozoite protein (CSP), Pvs25 and Pvs28 recombinant proteins of transmission-blocking vaccine candidates for P. vivax, and liver stage specific antigen-1 and -3 (PfLSA-1, PfLSA-3) for P. falciparum. Results Fourteen patients among 112 were found to be infected with P. vivax and 26 with P. falciparum by thick smear examination. Twenty-three patients were found to be infected with P. vivax, 19 with P. falciparum and five with both by thin smear examination. Blood samples were divided into two groups: Group I consisted of patients who were positive for infection by microscopic examination, and Group II consisted of those who showed symptoms, but were negative in microscopic examination. In P. falciparum, IgG against the blood stage antigen in Group I (80.8%) was higher than in Group II (70.0%). In P. vivax, IgG against the blood stage antigen in Group I (53.8%) was higher than in Group II (41.7%). However, the positivity rate of the PvCSP VK210 subtype in Group II (40.0%) was higher than in Group I (23.1%). Similarly for the PvCSP VK247 subtype, Group II (21.7%) was higher than that for Group I (9.6%). A similar pattern was observed in the ELISA using Pvs25 and Pvs28: positive rates of Group II were higher than those for Group I. However, those differences were not shown significant in statistics. Conclusions The positive rates for blood stage antigens of P. falciparum were higher in Group I than in Group II, but the positive rates for antigens of other stages (PfLSA-1 and -3) showed opposite

  17. Comparison of the antibody responses to Plasmodium vivax and Plasmodium falciparum antigens in residents of Mandalay, Myanmar.

    PubMed

    Kim, Tong-Soo; Kim, Hyung-Hwan; Kim, Jung-Yeon; Kong, Yoon; Na, Byoung-Kuk; Lin, Khin; Moon, Sung-Ung; Kim, Yeon-Joo; Kwon, Myoung-Hee; Sohn, Youngjoo; Kim, Hyuck; Lee, Hyeong-Woo

    2011-08-06

    The aim of this study was to investigate the profile of antibodies against several antigens of Plasmodium vivax and Plasmodium falciparum in Mandalay, Myanmar. Malaria parasites were identified by microscopic examination. To test the antibodies against P. vivax and P. falciparum in sera, an indirect immunofluorescence antibody test (IFAT) was performed using asexual blood parasite antigens. An enzyme-linked immunosorbent assay (ELISA) was performed with circumsporozoite protein (CSP), Pvs25 and Pvs28 recombinant proteins of transmission-blocking vaccine candidates for P. vivax, and liver stage specific antigen-1 and -3 (PfLSA-1, PfLSA-3) for P. falciparum. Fourteen patients among 112 were found to be infected with P. vivax and 26 with P. falciparum by thick smear examination. Twenty-three patients were found to be infected with P. vivax, 19 with P. falciparum and five with both by thin smear examination. Blood samples were divided into two groups: Group I consisted of patients who were positive for infection by microscopic examination, and Group II consisted of those who showed symptoms, but were negative in microscopic examination. In P. falciparum, IgG against the blood stage antigen in Group I (80.8%) was higher than in Group II (70.0%). In P. vivax, IgG against the blood stage antigen in Group I (53.8%) was higher than in Group II (41.7%). However, the positivity rate of the PvCSP VK210 subtype in Group II (40.0%) was higher than in Group I (23.1%). Similarly for the PvCSP VK247 subtype, Group II (21.7%) was higher than that for Group I (9.6%). A similar pattern was observed in the ELISA using Pvs25 and Pvs28: positive rates of Group II were higher than those for Group I. However, those differences were not shown significant in statistics. The positive rates for blood stage antigens of P. falciparum were higher in Group I than in Group II, but the positive rates for antigens of other stages (PfLSA-1 and -3) showed opposite results. Similar to P. falciparum, the

  18. Chromosome End Repair and Genome Stability in Plasmodium falciparum

    PubMed Central

    Calhoun, Susannah F.; Reed, Jake; Alexander, Noah; Mason, Christopher E.; Deitsch, Kirk W.

    2017-01-01

    ABSTRACT The human malaria parasite Plasmodium falciparum replicates within circulating red blood cells, where it is subjected to conditions that frequently cause DNA damage. The repair of DNA double-stranded breaks (DSBs) is thought to rely almost exclusively on homologous recombination (HR), due to a lack of efficient nonhomologous end joining. However, given that the parasite is haploid during this stage of its life cycle, the mechanisms involved in maintaining genome stability are poorly understood. Of particular interest are the subtelomeric regions of the chromosomes, which contain the majority of the multicopy variant antigen-encoding genes responsible for virulence and disease severity. Here, we show that parasites utilize a competitive balance between de novo telomere addition, also called “telomere healing,” and HR to stabilize chromosome ends. Products of both repair pathways were observed in response to DSBs that occurred spontaneously during routine in vitro culture or resulted from experimentally induced DSBs, demonstrating that both pathways are active in repairing DSBs within subtelomeric regions and that the pathway utilized was determined by the DNA sequences immediately surrounding the break. In combination, these two repair pathways enable parasites to efficiently maintain chromosome stability while also contributing to the generation of genetic diversity. PMID:28790200

  19. Resistance to Therapies for Infection by Plasmodium vivax

    PubMed Central

    Baird, J. Kevin

    2009-01-01

    The gravity of the threat posed by vivax malaria to public health has been poorly appreciated. The widely held misperception of Plasmodium vivax as being relatively infrequent, benign, and easily treated explains its nearly complete neglect across the range of biological and clinical research. Recent evidence suggests a far higher and more-severe disease burden imposed by increasingly drug-resistant parasites. The two frontline therapies against vivax malaria, chloroquine and primaquine, may be failing. Despite 60 years of nearly continuous use of these drugs, their respective mechanisms of activity, resistance, and toxicity remain unknown. Although standardized means of assessing therapeutic efficacy against blood and liver stages have not been developed, this review examines the provisional in vivo, ex vivo, and animal model systems for doing so. The rationale, design, and interpretation of clinical trials of therapies for vivax malaria are discussed in the context of the nuance and ambiguity imposed by the hypnozoite. Fielding new drug therapies against real-world vivax malaria may require a reworking of the strategic framework of drug development, namely, the conception, testing, and evaluation of sets of drugs designed for the cure of both blood and liver asexual stages as well as the sexual blood stages within a single therapeutic regimen. PMID:19597012

  20. Cloning of Plasmodium falciparum by single-cell sorting

    PubMed Central

    Miao, Jun; Li, Xiaolian; Cui, Liwang

    2010-01-01

    Malaria parasite cloning is traditionally carried out mainly by using the limiting dilution method, which is laborious, imprecise, and unable to distinguish multiply-infected RBCs. In this study, we used a parasite engineered to express green fluorescent protein (GFP) to evaluate a single-cell sorting method for rapidly cloning Plasmodium falciparum. By dividing a two dimensional scattergram from a cell sorter into 17 gates, we determined the parameters for isolating singly-infected erythrocytes and sorted them into individual cultures. Pre-gating of the engineered parasites for GFP allowed the isolation of almost 100% GFP-positive clones. Compared with the limiting dilution method, the number of parasite clones obtained by single-cell sorting was much higher. Molecular analyses showed that parasite isolates obtained by single-cell sorting were highly homogenous. This highly efficient single-cell sorting method should prove very useful for cloning both P. falciparum laboratory populations from genetic manipulation experiments and clinical samples. PMID:20435038

  1. [Thermostable extracellular cyclic nucleotide phosphodiesterase from Physarum polycephalum plasmodium].

    PubMed

    Nezvetskiĭ, A R; Orlova, T G; Beĭlina, S I; Orlov, N Ia

    2006-01-01

    The cyclic nucleotide phosphodiesterase secreted by Physarum polycephalum plasmodium into extracellular medium has been partially purified by DEAE cellulose chromatography, ultrafiltration, and HPLC. The results obtained by gel filtration, HPLC, electrophoresis, and isoelectric focusing suggest that, the native enzyme in solution is a monomer with a molecular mass of about 90 kDa and pI in the range 3.6 - 4.0. The Km values were estimated to be about 0.9 mM and 7.7 mM, respectively, and Vm for both substrates were similar (up to several thousand micromoles of cAMP hydrolyzed/hour per mg of enzyme). The partially purified enzyme was shown to be extremely stable. It did not lose the activity after heat treatment at 100 degrees C during 30 min. The enzyme was active in the presence of 1% SDS, but it was fully inactivated under the same conditions in the presence of beta-mercaptoethanol. The properties of the phosphodiesterase from Physarum polycephalum are discussed.

  2. A molecular marker of artemisinin-resistant Plasmodium falciparum malaria

    NASA Astrophysics Data System (ADS)

    Ariey, Frédéric; Witkowski, Benoit; Amaratunga, Chanaki; Beghain, Johann; Langlois, Anne-Claire; Khim, Nimol; Kim, Saorin; Duru, Valentine; Bouchier, Christiane; Ma, Laurence; Lim, Pharath; Leang, Rithea; Duong, Socheat; Sreng, Sokunthea; Suon, Seila; Chuor, Char Meng; Bout, Denis Mey; Ménard, Sandie; Rogers, William O.; Genton, Blaise; Fandeur, Thierry; Miotto, Olivo; Ringwald, Pascal; Le Bras, Jacques; Berry, Antoine; Barale, Jean-Christophe; Fairhurst, Rick M.; Benoit-Vical, Françoise; Mercereau-Puijalon, Odile; Ménard, Didier

    2014-01-01

    Plasmodium falciparum resistance to artemisinin derivatives in southeast Asia threatens malaria control and elimination activities worldwide. To monitor the spread of artemisinin resistance, a molecular marker is urgently needed. Here, using whole-genome sequencing of an artemisinin-resistant parasite line from Africa and clinical parasite isolates from Cambodia, we associate mutations in the PF3D7_1343700 kelch propeller domain (`K13-propeller') with artemisinin resistance in vitro and in vivo. Mutant K13-propeller alleles cluster in Cambodian provinces where resistance is prevalent, and the increasing frequency of a dominant mutant K13-propeller allele correlates with the recent spread of resistance in western Cambodia. Strong correlations between the presence of a mutant allele, in vitro parasite survival rates and in vivo parasite clearance rates indicate that K13-propeller mutations are important determinants of artemisinin resistance. K13-propeller polymorphism constitutes a useful molecular marker for large-scale surveillance efforts to contain artemisinin resistance in the Greater Mekong Subregion and prevent its global spread.

  3. Reduced erythrocyte deformability associated with hypoargininemia during Plasmodium falciparum malaria.

    PubMed

    Rey, Juliana; Buffet, Pierre A; Ciceron, Liliane; Milon, Geneviève; Mercereau-Puijalon, Odile; Safeukui, Innocent

    2014-01-20

    The mechanisms underlying reduced red blood cell (RBC) deformability during Plasmodium falciparum (Pf) malaria remain poorly understood. Here, we explore the possible involvement of the L-arginine and nitric oxide (NO) pathway on RBC deformability in Pf-infected patients and parasite cultures. RBC deformability was reduced during the acute attack (day0) and returned to normal values upon convalescence (day28). Day0 values correlated with plasma L-arginine levels (r = 0.69; p = 0.01) and weakly with parasitemia (r = -0.38; p = 0.006). In vitro, day0 patient's plasma incubated with ring-stage cultures at 41°C reduced RBC deformability, and this effect correlated strongly with plasma L-arginine levels (r = 0.89; p < 0.0001). Moreover, addition of exogenous L-arginine to the cultures increased deformability of both Pf-free and trophozoite-harboring RBCs. NO synthase activity, evidenced in Pf-infected RBCs, induced L-arginine-dependent NO production. These data show that hypoargininemia during P. falciparum malaria may altogether impair NO production and reduce RBC deformability, particularly at febrile temperature.

  4. Plasmodium falciparum accompanied the human expansion out of Africa.

    PubMed

    Tanabe, Kazuyuki; Mita, Toshihiro; Jombart, Thibaut; Eriksson, Anders; Horibe, Shun; Palacpac, Nirianne; Ranford-Cartwright, Lisa; Sawai, Hiromi; Sakihama, Naoko; Ohmae, Hiroshi; Nakamura, Masatoshi; Ferreira, Marcelo U; Escalante, Ananias A; Prugnolle, Franck; Björkman, Anders; Färnert, Anna; Kaneko, Akira; Horii, Toshihiro; Manica, Andrea; Kishino, Hirohisa; Balloux, Francois

    2010-07-27

    Plasmodium falciparum is distributed throughout the tropics and is responsible for an estimated 230 million cases of malaria every year, with a further 1.4 billion people at risk of infection. Little is known about the genetic makeup of P. falciparum populations, despite variation in genetic diversity being a key factor in morbidity, mortality, and the success of malaria control initiatives. Here we analyze a worldwide sample of 519 P. falciparum isolates sequenced for two housekeeping genes (63 single nucleotide polymorphisms from around 5000 nucleotides per isolate). We observe a strong negative correlation between within-population genetic diversity and geographic distance from sub-Saharan Africa (R(2) = 0.95) over Africa, Asia, and Oceania. In contrast, regional variation in transmission intensity seems to have had a negligible impact on the distribution of genetic diversity. The striking geographic patterns of isolation by distance observed in P. falciparum mirror the ones previously documented in humans and point to a joint sub-Saharan African origin between the parasite and its host. Age estimates for the expansion of P. falciparum further support that anatomically modern humans were infected prior to their exit out of Africa and carried the parasite along during their colonization of the world. 2010 Elsevier Ltd. All rights reserved.

  5. Effects of zinc-desferrioxamine on Plasmodium falciparum in culture.

    PubMed Central

    Chevion, M; Chuang, L; Golenser, J

    1995-01-01

    The zinc-desferrioxamine (Zn-DFO) complex is considered to be more permeative into parasitized erythrocytes than is the metal-free DFO. The former may penetrate the cell and exchange its bound zinc for ferric ions, rendering the iron unavailable for vital parasite functions. The effects of these compounds on the in vitro development of Plasmodium falciparum are compared. The results indicate that Zn-DFO is superior to DFO, especially at concentrations below 20 microM, as shown by decreased levels of hypoxanthine incorporation, lower levels of parasitemia, and interference with the life cycle of the parasite. At low concentrations, DFO even enhanced parasite growth. Such an enhancement was not observed following exposure to Zn-DFO. Experiments in which the compounds were removed from the cultures indicated that parasites treated with Zn-DFO are less likely to recover at a later stage. Since DFO has already been used in humans for the treatment of malaria, its complex with zinc, which is more effective in vitro, should also be examined in vivo. PMID:7486946

  6. In vitro activities of novel catecholate siderophores against Plasmodium falciparum.

    PubMed Central

    Pradines, B; Ramiandrasoa, F; Basco, L K; Bricard, L; Kunesch, G; Le Bras, J

    1996-01-01

    The activities of novel iron chelators, alone and in combination with chloroquine, quinine, or artemether, were evaluated in vitro against susceptible and resistant clones of Plasmodium falciparum with a semimicroassay system. N4-nonyl,N1,N8-bis(2,3-dihydroxybenzoyl) spermidine hydrobromide (compound 7) demonstrated the highest level of activity: 170 nM against a chloroquine-susceptible clone and 1 microM against a chloroquine-resistant clone (50% inhibitory concentrations). Compounds 6, 8, and 10 showed antimalarial activity with 50% inhibitory concentrations of about 1 microM. Compound 7 had no effect on the activities of chloroquine, quinine, and artemether against either clone, and compound 8 did not enhance the schizontocidal action of either chloroquine or quinine against the chloroquine-resistant clone. The incubation of compound 7 with FeCI3 suppressed or decreased the in vitro antimalarial activity of compound 7, while no effect was observed with incubation of compound 7 with CuSO4 and ZnSO4. These results suggest that iron deprivation may be the main mechanism of action of compound 7 against the malarial parasites. Chelator compounds 7 and 8 primarily affected trophozoite stages, probably by influencing the activity of ribonucleotide reductase, and thus inhibiting DNA synthesis. PMID:8878587

  7. Analysis of Breath Specimens for Biomarkers of Plasmodium falciparum Infection

    PubMed Central

    Berna, Amalia Z.; McCarthy, James S.; Wang, Rosalind X.; Saliba, Kevin J.; Bravo, Florence G.; Cassells, Julie; Padovan, Benjamin; Trowell, Stephen C.

    2015-01-01

    Currently, the majority of diagnoses of malaria rely on a combination of the patient's clinical presentation and the visualization of parasites on a stained blood film. Breath offers an attractive alternative to blood as the basis for simple, noninvasive diagnosis of infectious diseases. In this study, breath samples were collected from individuals during controlled malaria to determine whether specific malaria-associated volatiles could be detected in breath. We identified 9 compounds whose concentrations varied significantly over the course of malaria: carbon dioxide, isoprene, acetone, benzene, cyclohexanone, and 4 thioethers. The latter group, consisting of allyl methyl sulfide, 1-methylthio-propane, (Z)-1-methylthio-1-propene, and (E)-1-methylthio-1-propene, had not previously been associated with any disease or condition. Before the availability of antimalarial drug treatment, there was evidence of concurrent 48-hour cyclical changes in the levels of both thioethers and parasitemia. When thioether concentrations were subjected to a phase shift of 24 hours, a direct correlation between the parasitemia and volatile levels was revealed. Volatile levels declined monotonically approximately 6.5 hours after initial drug treatment, correlating with clearance of parasitemia. No thioethers were detected in in vitro cultures of Plasmodium falciparum. The metabolic origin of the thioethers is not known, but results suggest that interplay between host and parasite metabolic pathways is involved in the production of these thioethers. PMID:25810441

  8. Analysis of Breath Specimens for Biomarkers of Plasmodium falciparum Infection.

    PubMed

    Berna, Amalia Z; McCarthy, James S; Wang, Rosalind X; Saliba, Kevin J; Bravo, Florence G; Cassells, Julie; Padovan, Benjamin; Trowell, Stephen C

    2015-10-01

    Currently, the majority of diagnoses of malaria rely on a combination of the patient's clinical presentation and the visualization of parasites on a stained blood film. Breath offers an attractive alternative to blood as the basis for simple, noninvasive diagnosis of infectious diseases. In this study, breath samples were collected from individuals during controlled malaria to determine whether specific malaria-associated volatiles could be detected in breath. We identified 9 compounds whose concentrations varied significantly over the course of malaria: carbon dioxide, isoprene, acetone, benzene, cyclohexanone, and 4 thioethers. The latter group, consisting of allyl methyl sulfide, 1-methylthio-propane, (Z)-1-methylthio-1-propene, and (E)-1-methylthio-1-propene, had not previously been associated with any disease or condition. Before the availability of antimalarial drug treatment, there was evidence of concurrent 48-hour cyclical changes in the levels of both thioethers and parasitemia. When thioether concentrations were subjected to a phase shift of 24 hours, a direct correlation between the parasitemia and volatile levels was revealed. Volatile levels declined monotonically approximately 6.5 hours after initial drug treatment, correlating with clearance of parasitemia. No thioethers were detected in in vitro cultures of Plasmodium falciparum. The metabolic origin of the thioethers is not known, but results suggest that interplay between host and parasite metabolic pathways is involved in the production of these thioethers.

  9. Plasmodium falciparum Histones Induce Endothelial Proinflammatory Response and Barrier Dysfunction

    PubMed Central

    Gillrie, Mark R.; Lee, Kristine; Gowda, D. Channe; Davis, Shevaun P.; Monestier, Marc; Cui, Liwang; Hien, Tran Tinh; Day, Nicholas P.J.; Ho, May

    2012-01-01

    Plasmodium falciparum is a protozoan parasite of human erythrocytes that causes the most severe form of malaria. Severe P. falciparum infection is associated with endothelial activation and permeability, which are important determinants of the outcome of the infection. How endothelial cells become activated is not fully understood, particularly with regard to the effects of parasite subcomponents. We demonstrated that P. falciparum histones extracted from merozoites (HeH) directly stimulated the production of IL-8 and other inflammatory mediators by primary human dermal microvascular endothelial cells through a signaling pathway that involves Src family kinases and p38 MAPK. The stimulatory effect of HeH and recombinant P. falciparum H3 (PfH3) was abrogated by histone-specific antibodies. The release of nuclear contents on rupture of infected erythrocytes was captured by live cell imaging and confirmed by detecting nucleosomes in the supernatants of parasite cultures. HeH and recombinant parasite histones also induced endothelial permeability through a charge-dependent mechanism that resulted in disruption of junctional protein expression and cell death. Recombinant human activated protein C cleaved HeH and PfH3 and abrogated their proinflammatory effects. Circulating nucleosomes of both human and parasite origin were detected in the plasma of patients with falciparum malaria and correlated positively with disease severity. These results support a pathogenic role for both host- and pathogen-derived histones in P. falciparum-caused malaria. PMID:22260922

  10. Cloning of Plasmodium falciparum by single-cell sorting.

    PubMed

    Miao, Jun; Li, Xiaolian; Cui, Liwang

    2010-10-01

    Malaria parasite cloning is traditionally carried out mainly by using the limiting dilution method, which is laborious, imprecise, and unable to distinguish multiply-infected RBCs. In this study, we used a parasite engineered to express green fluorescent protein (GFP) to evaluate a single-cell sorting method for rapidly cloning Plasmodium falciparum. By dividing a two-dimensional scattergram from a cell sorter into 17 gates, we determined the parameters for isolating singly-infected erythrocytes and sorted them into individual cultures. Pre-gating of the engineered parasites for GFP allowed the isolation of almost 100% GFP-positive clones. Compared with the limiting dilution method, the number of parasite clones obtained by single-cell sorting was much higher. Molecular analyses showed that parasite isolates obtained by single-cell sorting were highly homogenous. This highly efficient single-cell sorting method should prove very useful for cloning both P. falciparum laboratory populations from genetic manipulation experiments and clinical samples. Copyright 2010 Elsevier Inc. All rights reserved.

  11. The crystal structure of superoxide dismutase from Plasmodium falciparum

    PubMed Central

    Boucher, Ian W; Brzozowski, Andrzej M; Brannigan, James A; Schnick, Claudia; Smith, Derek J; Kyes, Sue A; Wilkinson, Anthony J

    2006-01-01

    Background Superoxide dismutases (SODs) are important enzymes in defence against oxidative stress. In Plasmodium falciparum, they may be expected to have special significance since part of the parasite life cycle is spent in red blood cells where the formation of reactive oxygen species is likely to be promoted by the products of haemoglobin breakdown. Thus, inhibitors of P. falciparum SODs have potential as anti-malarial compounds. As a step towards their development we have determined the crystal structure of the parasite's cytosolic iron superoxide dismutase. Results The cytosolic iron superoxide dismutase from P. falciparum (PfFeSOD) has been overexpressed in E. coli in a catalytically active form. Its crystal structure has been solved by molecular replacement and refined against data extending to 2.5 Å resolution. The structure reveals a two-domain organisation and an iron centre in which the metal is coordinated by three histidines, an aspartate and a solvent molecule. Consistent with ultracentrifugation analysis the enzyme is a dimer in which a hydrogen bonding lattice links the two active centres. Conclusion The tertiary structure of PfFeSOD is very similar to those of a number of other iron-and manganese-dependent superoxide dismutases, moreover the active site residues are conserved suggesting a common mechanism of action. Comparison of the dimer interfaces of PfFeSOD with the human manganese-dependent superoxide dismutase reveals a number of differences, which may underpin the design of parasite-selective superoxide dismutase inhibitors. PMID:17020617

  12. Dissecting the role of glutathione biosynthesis in Plasmodium falciparum

    PubMed Central

    Patzewitz, Eva-Maria; Wong, Eleanor H; Müller, Sylke

    2012-01-01

    Glutathione (γ-glutamylcysteinyl-glycine, GSH) has vital functions as thiol redox buffer and cofactor of antioxidant and detoxification enzymes. Plasmodium falciparum possesses a functional GSH biosynthesis pathway and contains mM concentrations of the tripeptide. It was impossible to delete in P. falciparum the genes encoding γ-glutamylcysteine synthetase (γGCS) or glutathione synthetase (GS), the two enzymes synthesizing GSH, although both gene loci were not refractory to recombination. Our data show that the parasites cannot compensate for the loss of GSH biosynthesis via GSH uptake. This suggests an important if not essential function of GSH biosynthesis pathway for the parasites. Treatment with the irreversible inhibitor of γGCS L-buthionine sulfoximine (BSO) reduced intracellular GSH levels in P. falciparum and was lethal for their intra-erythrocytic development, corroborating the suggestion that GSH biosynthesis is important for parasite survival. Episomal expression of γgcs in P. falciparum increased tolerance to BSO attributable to increased levels of γGCS. Concomitantly expression of glutathione reductase was reduced leading to an increased GSH efflux. Together these data indicate that GSH levels are tightly regulated by a functional GSH biosynthesis and the reduction of GSSG. PMID:22151036

  13. The gene encoding topoisomerase II from Plasmodium falciparum.

    PubMed

    Cheesman, S; McAleese, S; Goman, M; Johnson, D; Horrocks, P; Ridley, R G; Kilbey, B J

    1994-07-11

    The gene for topoisomerase II has been isolated from genomic libraries of strain K1 of the human malarial parasite, Plasmodium falciparum. The sequence reveals an open reading frame of 4194 nucleotides which predicts a polypeptide of 1398 amino acids. There are apparently no introns. The sequence is present as a single copy which has an identity of 47.4% and a similarity of 65.4% with its human homologue. Sequences conserved in topoisomerase II from other species are present in Pftopoisomerase II but in addition it has two adjacent asparagine-rich insertions which are unique to it. We have also detected asparagine-rich regions in the gene for PfDNA polymerase alpha. The gene for Pftopoisomerase II has been localised to chromosome 14 and northern analysis reveals a transcript of 5.8 kb. Two independent antisera raised in mice against glutathione-S-transferase fusion proteins containing the amino terminal portion of the malarial protein detect a weak band on western blots at about 160kDa, the expected size of the protein. Use of the same antisera for immunofluorescence analysis suggests that the protein is present at all stages of intraerythrocytic growth of the parasite.

  14. Calcium regulation in the intraerythrocytic malaria parasite Plasmodium falciparum.

    PubMed

    Alleva, L M; Kirk, K

    2001-10-01

    The regulation of intracellular Ca(2+) in the intraerythrocytic form of the human malaria parasite, Plasmodium falciparum, was investigated using parasites 'isolated' from their host cells by saponin-permeabilisation of the erythrocyte membrane. The isolated parasites maintained tight control over their resting cytosolic Ca(2+) concentration which ranged from approximately 100 nM in the absence of extracellular Ca(2+) to approximately 700 nM in the presence of 1 mM extracellular Ca(2+). The parasite has two functionally discrete intracellular Ca(2+) stores. One is an 'endoplasmic reticulum (ER)-like' store, the other an 'acidic store'. The ER-like store was discharged by cyclopiazonic acid (CPA), an inhibitor of sarco/endoplasmic reticulum Ca(2+)-ATPases (SERCAs) of animal and plant cells, but not by thapsigargin (TG), a more specific inhibitor of SERCAs of animal cells. The acidic store was discharged by nigericin and by NH(4)(+). The amount of Ca(2+) in the ER-like store increased with increasing extracellular Ca(2+) concentration, whereas the amount of Ca(2+) in the acidic store did not. Ca(2+) released from the ER-like store by CPA was cleared from the parasite cytosol by uptake into the acidic store (over a range of extracellular Ca(2+) concentrations), consistent with the acidic store serving as a Ca(2+) reservoir within the intracellular parasite.

  15. Expression and characterization of the Plasmodium falciparum haemoglobinase falcipain-3.

    PubMed Central

    Sijwali, P S; Shenai, B R; Gut, J; Singh, A; Rosenthal, P J

    2001-01-01

    In the malaria parasite Plasmodium falciparum, erythrocytic trophozoites hydrolyse haemoglobin to provide amino acids for parasite protein synthesis. Cysteine protease inhibitors block parasite haemoglobin hydrolysis and development, indicating that cysteine proteases are required for these processes. Three papain-family cysteine protease sequences have been identified in the P. falciparum genome, but the specific roles of their gene products and other plasmodial proteases in haemoglobin hydrolysis are uncertain. Falcipain-2 was recently identified as a principal trophozoite cysteine protease and potential drug target. The present study characterizes the related P. falciparum cysteine protease falcipain-3. As is the case with falcipain-2, falcipain-3 is expressed by trophozoites and appears to be located within the food vacuole, the site of haemoglobin hydrolysis. Both proteases require a reducing environment and acidic pH for optimal activity, and both prefer peptide substrates with leucine at the P(2) position. The proteases differ, however, in that falcipain-3 undergoes efficient processing to an active form only at acidic pH, is more active and stable at acidic pH, and has much lower specific activity against typical papain-family peptide substrates, but has greater activity against native haemoglobin. Thus falcipain-3 is a second P. falciparum haemoglobinase that is particularly suited for the hydrolysis of native haemoglobin in the acidic food vacuole. The redundancy of cysteine proteases may offer optimized hydrolysis of both native haemoglobin and globin peptides. Consideration of both proteases will be necessary to evaluate cysteine protease inhibitors as antimalarial drugs. PMID:11716777

  16. A genome-wide map of diversity in Plasmodium falciparum.

    PubMed

    Volkman, Sarah K; Sabeti, Pardis C; DeCaprio, David; Neafsey, Daniel E; Schaffner, Stephen F; Milner, Danny A; Daily, Johanna P; Sarr, Ousmane; Ndiaye, Daouda; Ndir, Omar; Mboup, Soulyemane; Duraisingh, Manoj T; Lukens, Amanda; Derr, Alan; Stange-Thomann, Nicole; Waggoner, Skye; Onofrio, Robert; Ziaugra, Liuda; Mauceli, Evan; Gnerre, Sante; Jaffe, David B; Zainoun, Joanne; Wiegand, Roger C; Birren, Bruce W; Hartl, Daniel L; Galagan, James E; Lander, Eric S; Wirth, Dyann F

    2007-01-01

    Genetic variation allows the malaria parasite Plasmodium falciparum to overcome chemotherapeutic agents, vaccines and vector control strategies and remain a leading cause of global morbidity and mortality. Here we describe an initial survey of genetic variation across the P. falciparum genome. We performed extensive sequencing of 16 geographically diverse parasites and identified 46,937 SNPs, demonstrating rich diversity among P. falciparum parasites (pi = 1.16 x 10(-3)) and strong correlation with gene function. We identified multiple regions with signatures of selective sweeps in drug-resistant parasites, including a previously unidentified 160-kb region with extremely low polymorphism in pyrimethamine-resistant parasites. We further characterized 54 worldwide isolates by genotyping SNPs across 20 genomic regions. These data begin to define population structure among African, Asian and American groups and illustrate the degree of linkage disequilibrium, which extends over relatively short distances in African parasites but over longer distances in Asian parasites. We provide an initial map of genetic diversity in P. falciparum and demonstrate its potential utility in identifying genes subject to recent natural selection and in understanding the population genetics of this parasite.

  17. A systematic map of genetic variation in Plasmodium falciparum.

    PubMed

    Kidgell, Claire; Volkman, Sarah K; Daily, Johanna; Borevitz, Justin O; Plouffe, David; Zhou, Yingyao; Johnson, Jeffrey R; Le Roch, Karine; Sarr, Ousmane; Ndir, Omar; Mboup, Soulyemane; Batalov, Serge; Wirth, Dyann F; Winzeler, Elizabeth A

    2006-06-01

    Discovering novel genes involved in immune evasion and drug resistance in the human malaria parasite, Plasmodium falciparum, is of critical importance to global health. Such knowledge may assist in the development of new effective vaccines and in the appropriate use of antimalarial drugs. By performing a full-genome scan of allelic variability in 14 field and laboratory strains of P. falciparum, we comprehensively identified approximately 500 genes evolving at higher than neutral rates. The majority of the most variable genes have paralogs within the P. falciparum genome and may be subject to a different evolutionary clock than those without. The group of 211 variable genes without paralogs contains most known immunogens and a few drug targets, consistent with the idea that the human immune system and drug use is driving parasite evolution. We also reveal gene-amplification events including one surrounding pfmdr1, the P. falciparum multidrug-resistance gene, and a previously uncharacterized amplification centered around the P. falciparum GTP cyclohydrolase gene, the first enzyme in the folate biosynthesis pathway. Although GTP cyclohydrolase is not the known target of any current drugs, downstream members of the pathway are targeted by several widely used antimalarials. We speculate that an amplification of the GTP cyclohydrolase enzyme in the folate biosynthesis pathway may increase flux through this pathway and facilitate parasite resistance to antifolate drugs.

  18. Plasmodium falciparum Malaria: reduction of endothelial cell apoptosis in vitro.

    PubMed

    Hemmer, Christoph Josef; Lehr, Hans Anton; Westphal, Kathi; Unverricht, Marcus; Kratzius, Manja; Reisinger, Emil Christian

    2005-03-01

    Organ failure in Plasmodium falciparum malaria is associated with neutrophil activation and endothelial damage. This study investigates whether neutrophil-induced endothelial damage involves apoptosis and whether it can be prevented by neutralization of neutrophil secretory products. Endothelial cells from human umbilical veins were coincubated with neutrophils from healthy donors and with sera from eight patients with P. falciparum malaria, three patients with P. vivax malaria, and three healthy controls. Endothelial apoptosis was demonstrated by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) and annexin V staining. The rate of apoptosis of cells was markedly increased after incubation with patient serum compared to that with control serum. Apoptosis was most pronounced after incubation with sera from two patients with fatal cases of P. falciparum malaria, followed by sera of survivors with severe P. falciparum malaria and, finally, by sera of patients with mild P. falciparum and P. vivax malaria. Ascorbic acid, tocopherol, and ulinastatin reduced the apoptosis rate, but gabexate mesilate and pentoxifylline did not. Furthermore, in fatal P. falciparum malaria, apoptotic endothelial cells were identified in renal and pulmonary tissue by TUNEL staining. These findings show that apoptosis caused by neutrophil secretory products plays a major role in endothelial cell damage in malaria. The antioxidants ascorbic acid and tocopherol and the protease inhibitor ulinastatin can reduce malaria-associated endothelial apoptosis in vitro.

  19. Current status of the Plasmodium falciparum genome project.

    PubMed

    Dame, J B; Arnot, D E; Bourke, P F; Chakrabarti, D; Christodoulou, Z; Coppel, R L; Cowman, A F; Craig, A G; Fischer, K; Foster, J; Goodman, N; Hinterberg, K; Holder, A A; Holt, D C; Kemp, D J; Lanzer, M; Lim, A; Newbold, C I; Ravetch, J V; Reddy, G R; Rubio, J; Schuster, S M; Su, X Z; Thompson, J K; Werner, E B

    1996-07-01

    The Plasmodium falciparum Genome Project is a collaborative effort by many laboratories that will provide detailed molecular information about the parasite, which may be used for developing practical control measures. Initial goals are to prepare an electronically indexed clone bank containing partially sequenced clones representing up to 80% of the parasite's genes and to prepare an ordered set of overlapping clones spanning each of the parasite's 14 chromosomes. Currently, clones of genomic DNA, prepared as yeast artificial chromosomes, are arranged into contigs covering approximately 70% of the genome of parasite clone 3D7, gene sequence tags are available from more than contigs covering approximately 70% of the genome of parasite clone 3D7, gene sequence tags are available from more than 20% of the parasite's genes, and approximately 5% of the parasite's genes are tentatively identified from similarity searches of entries in the international sequence databases. A total of > 0.5 Mb of P. falciparum sequence tag data is available. The gene sequence tags are presently being used to complete YAC contig assembly and localize the cloned genes to positions on the physical map in preparation for sequencing the genome. Routes of access to project information and services are described.

  20. Genetic diversity of Plasmodium vivax in clinical isolates from Bangladesh.

    PubMed

    Kibria, Mohammad Golam; Elahi, Rubayet; Mohon, Abu Naser; Khan, Wasif A; Haque, Rashidul; Alam, Mohammad Shafiul

    2015-07-11

    Plasmodium vivax is the second most prevalent human malaria parasite in Bangladesh; however, there are no data of its genetic diversity. Several molecular markers are available where Pvcsp, Pvmsp 1 and Pvmsp 3α are most commonly used for P. vivax genotyping studies. The aim of the study was to investigate the population structure of P. vivax in Bangladesh. A total of 102 P. vivax-positive blood samples were collected from different malaria-endemic areas in Bangladesh and subsequently analysed for those three genotyping markers. Nested PCR was performed for diagnosis and genotyping analysis followed by PCR-RFLP to detect genetic diversity using Pvcsp, Pvmsp 1 and Pvmsp 3α markers. Analysis of Pvcsp showed that the VK210 repeat type was highly prevalent (64.7%, 66/102) compared to VK247 (35.3%, 36/102), although the prevalence of VK247 was higher than other Southeast Asian countries. Analysis of these three genes revealed a diverse, circulating population of P. vivax where a total of ten, 56 and 35 distinct genotypes were detected for Pvcsp, Pvmsp 1 and Pvmsp 3α, respectively. This genotyping observation of P. vivax is the first report from Bangladesh and will provide valuable information for establishing the genotyping methods and circulating genetic variants of these three markers available in Bangladesh.

  1. International population movements and regional Plasmodium falciparum malaria elimination strategies

    PubMed Central

    Tatem, Andrew J.; Smith, David L.

    2010-01-01

    Calls for the eradication of malaria require the development of global and regional strategies based on a strong and consistent evidence base. Evidence from the previous global malaria eradication program and more recent transborder control campaigns have shown the importance of accounting for human movement in introducing infections to areas targeted for elimination. Here, census-based migration data were analyzed with network analysis tools, Plasmodium falciparum malaria transmission maps, and global population databases to map globally communities of countries linked by relatively high levels of infection movements. The likely principal sources and destinations of imported cases in each region were also mapped. Results indicate that certain groups of countries, such as those in West Africa and central Asia are much more strongly connected by relatively high levels of population and infection movement than others. In contrast, countries such as Ethiopia and Myanmar display significantly greater isolation in terms of likely infection movements in and out. The mapping here of both communities of countries linked by likely higher levels of infection movement, and “natural” migration boundaries that display reduced movement of people and infections between regions has practical utility. These maps can inform the design of malaria elimination strategies by identifying regional communities of countries afforded protection from recolonization by surrounding regions of reduced migration. For more isolated countries, a nationally focused control or elimination program is likely to stand a better chance of success than those receiving high levels of visitors and migrants from high-transmission regions. PMID:20566870

  2. Retinal Changes in Uncomplicated and Severe Plasmodium knowlesi Malaria.

    PubMed

    Govindasamy, Gayathri; Barber, Bridget E; Ghani, Shuaibah A; William, Timothy; Grigg, Matthew J; Borooah, Shyamanga; Dhillon, Bal; Dondorp, Arjen M; Yeo, Tsin W; Anstey, Nicholas M; Maude, Richard J

    2016-05-01

    Plasmodium knowlesi causes severe malaria, but its pathogenesis is poorly understood. Retinal changes provide insights into falciparum malaria pathogenesis but have not been studied in knowlesi malaria. An observational study was conducted in Malaysian adults hospitalized with severe (n = 20) and nonsevere (n = 24) knowlesi malaria using indirect ophthalmoscopy (n = 44) and fundus photography (n = 29). The patients' median age was 44 years (range, 18-74 years). No coma or deaths occurred. Photography detected retinal changes in 11 of 12 patients (92%) with severe and 14 of 17 (82%) with nonsevere knowlesi malaria. Nonspecific retinal whitening occurred in 3 (35%) and 5 (29%) patients with severe and nonsevere disease, respectively; hemorrhages in 2 (17%) and 3 (18%); loss of retinal pigment epithelium in 1 (8%) and 4 (24%); and drusen in 9 (71%) and 12 (75%). All changes were mild, with no significant differences between severe and nonsevere disease. Patients with retinal hemorrhages had lower platelet counts than those without (median, 22 vs 43 × 10(9)/L; P= .04). The paucity of specific retinal findings associated with disease severity in knowlesi malaria contrasts with the retinopathy of severe adult falciparum malaria with and without coma, suggesting that falciparum-like microvascular sequestration in the brain is not a major component in severe knowlesi malaria pathogenesis. © The Author 2015. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

  3. Experimental Immunization Based on Plasmodium Antigens Isolated by Antibody Affinity

    PubMed Central

    Kamali, Ali N.; Marín-García, Patricia; Azcárate, Isabel G.; Puyet, Antonio; Diez, Amalia; Bautista, José M.

    2015-01-01

    Vaccines blocking malaria parasites in the blood-stage diminish mortality and morbidity caused by the disease. Here, we isolated antigens from total parasite proteins by antibody affinity chromatography to test an immunization against lethal malaria infection in a murine model. We used the sera of malaria self-resistant ICR mice to lethal Plasmodium yoelii yoelii 17XL for purification of their IgGs which were subsequently employed to isolate blood-stage parasite antigens that were inoculated to immunize BALB/c mice. The presence of specific antibodies in vaccinated mice serum was studied by immunoblot analysis at different days after vaccination and showed an intensive immune response to a wide range of antigens with molecular weight ranging between 22 and 250 kDa. The humoral response allowed delay of the infection after the inoculation to high lethal doses of P. yoelii yoelii 17XL resulting in a partial protection against malaria disease, although final survival was managed in a low proportion of challenged mice. This approach shows the potential to prevent malaria disease with a set of antigens isolated from blood-stage parasites. PMID:26539558

  4. Polycyclic amines as chloroquine resistance modulating agents in Plasmodium falciparum.

    PubMed

    Joubert, Jacques; Kapp, Erika; Taylor, Dale; Smith, Peter J; Malan, Sarel F

    2016-02-15

    Pentacycloundecylamines (PCUs) and adamantane amines, such as NGP1-01 (1) and amantadine, have shown significant channel blocking activities. They are postulated to act as chemosensitizers and circumvent the resistance of the plasmodia parasite against chloroquine (CQ) by inhibiting the p-glycoprotein efflux pump and enabling the accumulation of CQ inside the parasite digestive vacuole. Twelve polycyclic amines containing either a PCU or adamantane amine moiety conjugated to different aromatic functionalities through various tethered linkers were selected based on their channel blocking abilities and evaluated as potential chemosensitizers. Compounds 2, 4, 5 and 10 showed significant voltage-gated calcium channel (VGCC) blocking ability (IC50=0.27-35 μM) and were able to alter the CQ IC50 in differing degrees (45-81%) in the multidrug resistant Plasmodium falciparum Dd2 isolate. Among them, the PCU-dansyl amine compound (4) displayed the best potential to act as a chemosensitizer against the Dd2 strain at a 1 μM concentration (RMI=0.19) while displaying moderate antiplasmodial activity (Dd2 IC50=6.25 μM) and low in vitro cytotoxicity against a mammalian cell line (CHO, IC50=119 μM). Compounds 2 and 10 also showed some promising chemosensitizing abilities (RMI=0.36 and 0.35 respectively). A direct correlation was found between the VGCC blocking ability of these polycyclic amines and their capacity to act as CQ resistance modulating agents.

  5. Genetic diversity of Plasmodium vivax in Kolkata, India

    PubMed Central

    Kim, Jung-Ryong; Imwong, Mallika; Nandy, Amitabha; Chotivanich, Kesinee; Nontprasert, Apichart; Tonomsing, Naowarat; Maji, Ardhendu; Addy, Manjulika; Day, Nick PJ; White, Nicholas J; Pukrittayakamee, Sasithon

    2006-01-01

    Background Plasmodium vivax malaria accounts for approximately 60% of malaria cases in Kolkata, India. There has been limited information on the genotypic polymorphism of P. vivax in this malaria endemic area. Three highly polymorphic and single copy genes were selected for a study of genetic diversity in Kolkata strains. Methods Blood from 151 patients with P. vivax infection diagnosed in Kolkata between April 2003 and September 2004 was genotyped at three polymorphic loci: the P. vivax circumsporozoite protein (pvcs), the merozoite surface protein 1 (pvmsp1) and the merozoite surface protein 3-alpha (pvmsp3-alpha). Results Analysis of these three genetic markers revealed that P. vivax populations in Kolkata are highly diverse. A large number of distinguishable alleles were found from three genetic markers: 11 for pvcs, 35 for pvmsp1 and 37 for pvmsp3-alpha. These were, in general, randomly distributed amongst the isolates. Among the 151 isolates, 142 unique genotypes were detected the commonest genotype at a frequency of less than 2% (3/151). The overall rate of mixed genotype infections was 10.6%. Conclusion These results indicate that the P. vivax parasite population is highly diverse in Kolkata, despite the low level of transmission. The genotyping protocols used in this study may be useful for differentiating re-infection from relapse and recrudescence in studies assessing of malarial drug efficacy in vivax malaria. PMID:16907979

  6. Synchronous culture of Plasmodium falciparum at high parasitemia levels.

    PubMed

    Radfar, Azar; Méndez, Darío; Moneriz, Carlos; Linares, María; Marín-García, Patricia; Puyet, Antonio; Diez, Amalia; Bautista, José M

    2009-01-01

    This protocol describes a method for preparing cultures of Plasmodium falciparum synchronized at any intraerythrocytic stage. Using this method, around 60% parasitized cells may be obtained. On the basis of Trager and Jensen's original continuous culture method, our approach relies on the use of fresh human blood not older than 2 weeks, a low hematocrit between 0.8 and 1.5%, a starting frozen inoculum of 10% ring-stage parasitemia, human serum replaced with AlbuMAX I and alternating sorbitol and Percoll synchronization methods to shorten the cycle window to 4-6 h and reduce sorbitol toxicity. From our synchronized high parasite density cultures, 3-5 ml of infected red blood cells can be obtained in 1 week, corresponding to 1.2 mg of total parasite protein per ml of harvested culture. On the basis of the variables parasitemia and packed cell volume, we provide an equation to accurately calculate the amount of complete medium required every 24 h corrected for the cycle stage and capacity of the culture flask. Ten days suffice to complete the protocol from a frozen stock of parasites.

  7. Biology of Human Malaria Plasmodia Including Plasmodium Knowlesi

    PubMed Central

    Antinori, Spinello; Galimberti, Laura; Milazzo, Laura; Corbellino, Mario

    2012-01-01

    Malaria is a vector-borne infection caused by unicellular parasite of the genus Plasmodium. Plasmodia are obligate intracellular parasites that are able to infect and replicate within the erythrocytes after a clinically silent replication phase in the liver. Four species (P.falciparum, P.malariae, P.ovale and P.vivax) are traditionally recognized as responsible of natural infection in human beings but the recent upsurge of P.knowlesi malaria in South-East Asia has led clinicians to consider it as the fifth human malaria parasite. Recent studies in wild-living apes in Africa have revealed that P.falciparum, the most deadly form of human malaria, is not only human-host restricted as previously believed and its phylogenetic lineage is much more complex with new species identified in gorilla, bonobo and chimpanzee. Although less impressive, new data on biology of P.malariae, P.ovale and P.vivax are also emerging and will be briefly discussed in this review. PMID:22550559

  8. A molecular marker of artemisinin-resistant Plasmodium falciparum malaria

    PubMed Central

    Ariey, Frédéric; Witkowski, Benoit; Amaratunga, Chanaki; Beghain, Johann; Langlois, Anne-Claire; Khim, Nimol; Kim, Saorin; Duru, Valentine; Bouchier, Christiane; Ma, Laurence; Lim, Pharath; Leang, Rithea; Duong, Socheat; Sreng, Sokunthea; Suon, Seila; Chuor, Char Meng; Bout, Denis Mey; Ménard, Sandie; Rogers, William O.; Genton, Blaise; Fandeur, Thierry; Miotto, Olivo; Ringwald, Pascal; Le Bras, Jacques; Berry, Antoine; Barale, Jean-Christophe; Fairhurst, Rick M.; Benoit-Vical, Françoise; Mercereau-Puijalon, Odile; Ménard, Didier

    2016-01-01

    Plasmodium falciparum resistance to artemisinin derivatives in southeast Asia threatens malaria control and elimination activities worldwide. To monitor the spread of artemisinin resistance, a molecular marker is urgently needed. Here, using whole-genome sequencing of an artemisinin-resistant parasite line from Africa and clinical parasite isolates from Cambodia, we associate mutations in the PF3D7_1343700 kelch propeller domain (‘K13-propeller’) with artemisinin resistance in vitro and in vivo. Mutant K13-propeller alleles cluster in Cambodian provinces where resistance is prevalent, and the increasing frequency of a dominant mutant K13-propeller allele correlates with the recent spread of resistance in western Cambodia. Strong correlations between the presence of a mutant allele, in vitro parasite survival rates and in vivo parasite clearance rates indicate that K13-propeller mutations are important determinants of artemisinin resistance. K13-propeller polymorphism constitutes a useful molecular marker for large-scale surveillance efforts to contain artemisinin resistance in the Greater Mekong Subregion and prevent its global spread. PMID:24352242

  9. Molecular and structural insight into plasmodium falciparum RIO2 kinase.

    PubMed

    Chouhan, Devendra K; Sharon, Ashoke; Bal, Chandralata

    2013-02-01

    Among approximately 65 kinases of the malarial genome, RIO2 (right open reading frame) kinase belonging to the atypical class of kinase is unique because along with a kinase domain, it has a highly conserved N-terminal winged helix (wHTH) domain. The wHTH domain resembles the wing like domain found in DNA binding proteins and is situated near to the kinase domain. Ligand binding to this domain may reposition the kinase domain leading to inhibition of enzyme function and could be utilized as a novel allosteric site to design inhibitor. In the present study, we have generated a model of RIO2 kinase from Plasmodium falciparum utilizing multiple modeling, simulation approach. A novel putative DNA-binding site is identified for the first time in PfRIO2 kinase to understand the DNA binding events involving wHTH domain and flexible loop. Induced fit DNA docking followed by minimization, molecular dynamics simulation, energetic scoring and binding mode studies are used to reveal the structural basis of PfRIO2-ATP-DNA complex. Ser105 as a potential site of phosphorylation is revealed through the structural studies of ATP binding in PfRIO2. Overall the present study discloses the structural facets of unknown PfRIO2 complex and opens an avenue toward exploration of novel drug target.

  10. Plasmodium Drug Targets Outside the Genetic Control of the Parasite

    PubMed Central

    Sullivan, David J.

    2014-01-01

    Drug development often seeks to find “magic bullets” which target microbiologic proteins while not affecting host proteins. Paul Ehrlich tested methylene blue as an antimalarial but this dye was not superior to quinine. Many successful antimalarial therapies are “magic shotguns” which target many Plasmodium pathways with little interference in host metabolism. Two malaria drug classes, the 8-aminoquinolines and the artemisinins interact with cytochrome P450s and host iron protoporphyrin IX or iron, respectively, to generate toxic metabolites and/or radicals, which kill the parasite by interference with many proteins. The non 8-amino antimalarial quinolines like quinine or piperaquine bind heme to inhibit the process of heme crystallization, which results in multiple enzyme inhibition and membrane dysfunction. The quinolines and artemisinins are rapidly parasiticidal in contrast to metal chelators, which have a slower parasite clearance rate with higher drug concentrations. Iron chelators interfere with the artemisinins but otherwise represent a strategy of targeting multiple enzymes containing iron. Interest has been revived in antineoplastic drugs that target DNA metabolism as antimalarials. Specific drug targeting or investigation of the innate immunity directed to the more permeable trophozoite or schizont infected erythrocyte membrane has been under explored. Novel drug classes in the antimalarial development pipeline which either target multiple proteins or unchangeable cellular targets will slow the pace of drug resistance acquisition. PMID:22973888

  11. Plasmodium genetic loci linked to host cytokine and chemokine responses

    PubMed Central

    Pattaradilokrat, Sittiporn; Li, Jian; Wu, Jian; Qi, Yanwei; Eastman, Richard T.; Zilversmit, Martine; Nair, Sethu C.; Huaman, Maria Cecilia; Quinones, Mariam; Jiang, Hongying; Li, Na; Zhu, Jun; Zhao, Keji; Kaneko, Osamu; Long, Carole A.; Su, Xin-zhuan

    2014-01-01

    Both host and parasite factors contribute to disease severity of malaria infection; however, the molecular mechanisms responsible for the disease and the host-parasite interactions involved remain largely unresolved. To investigate effects of parasite factors on host immune responses and pathogenesis, we measured levels of plasma cytokines/chemokines (CC) and growth rates in mice infected with two Plasmodium yoelii strains having different virulence phenotypes and in progeny from a genetic cross of the two parasites. Quantitative trait loci (QTL) analysis linked levels of many CCs, particularly IL-1β, IP-10, IFN-γ, MCP-1, and MIG, and early parasite growth rate to loci on multiple parasite chromosomes, including chromosomes 7, 9, 10, 12, and 13. Comparison of the genome sequences spanning the mapped loci revealed various candidate genes. The loci on chromosome 7 and 13 had significant (p < 0.005) additive effects on IL-1β, IL-5, and IP-10 responses, and the chromosome 9 and 12 loci had significant (p = 0.017) interaction. Infection of knockout mice showed critical roles of MCP-1 and IL-10 in parasitemia control and host mortality. These results provide important information for better understanding of malaria pathogenesis and can be used to examine the role of these factors in human malaria infection. PMID:24452266

  12. Plasmodium genetic loci linked to host cytokine and chemokine responses.

    PubMed

    Pattaradilokrat, S; Li, J; Wu, J; Qi, Y; Eastman, R T; Zilversmit, M; Nair, S C; Huaman, M C; Quinones, M; Jiang, H; Li, N; Zhu, J; Zhao, K; Kaneko, O; Long, C A; Su, X-z

    2014-01-01

    Both host and parasite factors contribute to disease severity of malaria infection; however, the molecular mechanisms responsible for the disease and the host-parasite interactions involved remain largely unresolved. To investigate the effects of parasite factors on host immune responses and pathogenesis, we measured levels of plasma cytokines/chemokines (CCs) and growth rates in mice infected with two Plasmodium yoelii strains having different virulence phenotypes and in progeny from a genetic cross of the two parasites. Quantitative trait loci (QTL) analysis linked levels of many CCs, particularly IL-1β, IP-10, IFN-γ, MCP-1 and MIG, and early parasite growth rate to loci on multiple parasite chromosomes, including chromosomes 7, 9, 10, 12 and 13. Comparison of the genome sequences spanning the mapped loci revealed various candidate genes. The loci on chromosomes 7 and 13 had significant (P<0.005) additive effects on IL-1β, IL-5 and IP-10 responses, and the chromosome 9 and 12 loci had significant (P=0.017) interaction. Infection of knockout mice showed critical roles of MCP-1 and IL-10 in parasitemia control and host mortality. These results provide important information for a better understanding of malaria pathogenesis and can be used to examine the role of these factors in human malaria infection.

  13. Postrenal transplant Plasmodium vivax malaria: neglected and not benign.

    PubMed

    Kute, Vivek B; Vanikar, Aruna V; Shah, Pankaj R; Shrimali, Jigar D; Gumber, Manoj R; Patel, Himanshu V; Modi, Pranjal R; Trivedi, Hargovind L

    2013-04-01

    Plasmodium vivax is causing increasingly more cases of severe malaria worldwide. We reported a case of postrenal transplantation acute kidney injury (AKI) associated with P. vivax, a neglected human malaria parasite. The diagnosis of P. vivax monoinfection was confirmed by direct visualization of the parasite in blood smear and rapid diagnostic test. On admission, serum creatinine (SCr.) increased from 1.45 to 3.7 mg/dl. The other etiologies of fever and AKI were ruled out. He responded to prompt therapy with antimalarial drugs. There was no change in tacrolimus trough level before and after antimalarial drugs. Two weeks after discharge, his SCr. was 1.43 mg/dl. Our patient lived in an endemic malarial area and the transplant took place in December 2010. The patient subsequently presented with clinical malaria in June 2012, so we thought that posttransplantation transmission by the mosquito was a possibility and very less likely that other dormant form of the parasite had been the source of the clinical infection. P. vivax can lead to as AKI in renal transplant recipient. P. vivax should be considered in the differential diagnosis of fever in transplant recipients who had received organs or blood products from malaria-endemic area to facilitate a prompt diagnosis and adequate treatment.

  14. Complexity of Infection and Genetic Diversity in Cambodian Plasmodium vivax

    PubMed Central

    Friedrich, Lindsey R.; Popovici, Jean; Kim, Saorin; Dysoley, Lek; Zimmerman, Peter A.; Menard, Didier; Serre, David

    2016-01-01

    Background Plasmodium vivax is the most widely distributed human malaria parasite with 2.9 billion people living in endemic areas. Despite intensive malaria control efforts, the proportion of cases attributed to P. vivax is increasing in many countries. Genetic analyses of the parasite population and its dynamics could provide an assessment of the efficacy of control efforts, but, unfortunately, these studies are limited in P. vivax by the lack of informative markers and high-throughput genotyping methods. Methodology/Principal Findings We developed a sequencing-based assay to simultaneously genotype more than 100 SNPs and applied this approach to ~500 P. vivax-infected individuals recruited across nine locations in Cambodia between 2004 and 2013. Our analyses showed that the vast majority of infections are polyclonal (92%) and that P. vivax displays high genetic diversity in Cambodia without apparent geographic stratification. Interestingly, our analyses also revealed that the proportion of monoclonal infections significantly increased between 2004 and 2013, possibly suggesting that malaria control strategies in Cambodia may be successfully affecting the parasite population. Conclusions/Significance Our findings demonstrate that this high-throughput genotyping assay is efficient in characterizing P. vivax diversity and can provide valuable insights to assess the efficacy of malaria elimination programs or to monitor the spread of specific parasites. PMID:27018585

  15. Plasmodium falciparum heat shock protein 70 lacks immune modulatory activity.

    PubMed

    Pooe, Ofentse Jacob; Köllisch, Gabriele; Heine, Holger; Shonhai, Addmore

    2017-02-14

    Heat shock protein 70 (Hsp70) family are conserved molecules that constitute a major part of the cell's protein folding machinery. The role of Hsp70s of parasitic origin in host cell immune modulation has remained contentious. This is largely due to the fact that several studies implicating Hsp70 in immune modulation rely on the use of recombinant protein derived from bacteria which is often fraught contamination. Thus, in the current study, we expressed recombinant Plasmodium falciparum Hsp70 (PfHsp70) using in three bacterial expression hosts: E. coli XL1 Blue, E. coli ClearColi BL21 and Brevibacillus choshinensis, respectively. We further investigated the immunostimulatory capability of the protein by assessing cytokine production by murine immune cells cultured in the presence of the protein. Recombinant PfHsp70 obtained from E. coli XL1 Blue expression host induced IL6 and IL8 cytokines. On the other hand, PfHsp70 produced in E. coli ClearColi and B. choshinensis expression systems was associated with no detectable traces of LPS and exhibited no immunomodulatory activity. Our findings suggest that PfHsp70 does not possess immunomodulatory function. Furthermore, our study suggests that E. coli ClearColi and B. choshinensis are versatile for the production of recombinant protein for use in immunomodulatory studies.

  16. A molecular marker of artemisinin-resistant Plasmodium falciparum malaria.

    PubMed

    Ariey, Frédéric; Witkowski, Benoit; Amaratunga, Chanaki; Beghain, Johann; Langlois, Anne-Claire; Khim, Nimol; Kim, Saorin; Duru, Valentine; Bouchier, Christiane; Ma, Laurence; Lim, Pharath; Leang, Rithea; Duong, Socheat; Sreng, Sokunthea; Suon, Seila; Chuor, Char Meng; Bout, Denis Mey; Ménard, Sandie; Rogers, William O; Genton, Blaise; Fandeur, Thierry; Miotto, Olivo; Ringwald, Pascal; Le Bras, Jacques; Berry, Antoine; Barale, Jean-Christophe; Fairhurst, Rick M; Benoit-Vical, Françoise; Mercereau-Puijalon, Odile; Ménard, Didier

    2014-01-02

    Plasmodium falciparum resistance to artemisinin derivatives in southeast Asia threatens malaria control and elimination activities worldwide. To monitor the spread of artemisinin resistance, a molecular marker is urgently needed. Here, using whole-genome sequencing of an artemisinin-resistant parasite line from Africa and clinical parasite isolates from Cambodia, we associate mutations in the PF3D7_1343700 kelch propeller domain ('K13-propeller') with artemisinin resistance in vitro and in vivo. Mutant K13-propeller alleles cluster in Cambodian provinces where resistance is prevalent, and the increasing frequency of a dominant mutant K13-propeller allele correlates with the recent spread of resistance in western Cambodia. Strong correlations between the presence of a mutant allele, in vitro parasite survival rates and in vivo parasite clearance rates indicate that K13-propeller mutations are important determinants of artemisinin resistance. K13-propeller polymorphism constitutes a useful molecular marker for large-scale surveillance efforts to contain artemisinin resistance in the Greater Mekong Subregion and prevent its global spread.

  17. Sickle Cell Trait Protects Against Plasmodium falciparum Infection

    PubMed Central

    Billo, Mounkaila A.; Johnson, Eric S.; Doumbia, Seydou O.; Poudiougou, Belco; Sagara, Issaka; Diawara, Sory I.; Diakité, Mahamadou; Diallo, Mouctar; Doumbo, Ogobara K.; Tounkara, Anatole; Rice, Janet; James, Mark A.; Krogstad, Donald J.

    2012-01-01

    Although sickle cell trait protects against severe disease due to Plasmodium falciparum, it has not been clear whether sickle trait also protects against asymptomatic infection (parasitemia). To address this question, the authors identified 171 persistently smear-negative children and 450 asymptomatic persistently smear-positive children in Bancoumana, Mali (June 1996 to June 1998). They then followed both groups for 2 years using a cohort-based strategy. Among the 171 children with persistently negative smears, the median time for conversion to smear-positive was longer for children with sickle trait than for children without (274 vs. 108 days, P < 0.001; Cox hazard ratio = 0.56, 95% confidence interval: 0.33, 0.96; P = 0.036). Similar differences were found in the median times to reinfection after spontaneous clearance without treatment (365 days vs. 184 days; P = 0.01). Alternatively, among the 450 asymptomatic children with persistently positive smears, the median time for conversion to smear-negative (spontaneous clearance) was shorter for children with sickle trait than for children without (190 vs. 365 days; P = 0.02). These protective effects of sickle trait against asymptomatic P. falciparum infection under conditions of natural transmission were demonstrable using a cohort-based approach but not when the same data were examined using a cross-sectional approach. PMID:23035141

  18. Key Knowledge Gaps for Plasmodium vivax Control and Elimination

    PubMed Central

    Bassat, Quique; Velarde, Mar; Mueller, Ivo; Lin, Jessica; Leslie, Toby; Wongsrichanalai, Chansuda; Baird, J. Kevin

    2016-01-01

    There is inadequate understanding of the biology, pathology, transmission, and control of Plasmodium vivax, the geographically most widespread cause of human malaria. During the last decades, study of this species was neglected, in part due to the erroneous belief that it is intrinsically benign. In addition, many technical challenges in culturing the parasite also hampered understanding its fundamental biology and molecular and cellular responses to chemotherapeutics. Research on vivax malaria needs to be substantially expanded over the next decade to accelerate its elimination and eradication. This article summarizes key knowledge gaps identified by researchers, national malaria control programs, and other stakeholders assembled by the World Health Organization to develop strategies for controlling and eliminating vivax malaria. The priorities presented in this article emerged in these technical discussions, and were adopted by expert consensus of the authors. All involved understood the priority placed upon pragmatism in this research agenda, that is, focus upon tools delivering better prevention, diagnosis, treatment, and surveillance of P. vivax. PMID:27430544

  19. Characterisation of exogenous folate transport in Plasmodium falciparum.

    PubMed

    Wang, Ping; Wang, Qi; Sims, Paul F G; Hyde, John E

    2007-07-01

    Folate salvage by Plasmodium falciparum is an important source of key cofactors, but little is known about the underlying mechanism. Using synchronised parasite cultures, we observed that uptake of this dianionic species against the negative-inward electrochemical gradient is highly dependent upon cell-cycle stage, temperature and pH, but not on mono- or divalent metal ions. Energy dependence was tested with different sugars; glucose was necessary for folate import, although fructose was also able to function in this role, unlike sugars that cannot be processed through the glycolytic pathway. Import into both infected erythrocytes and free parasites was strongly inhibited by the anion-channel blockers probenecid and furosemide, which are likely to be acting predominantly on specific folate transporters in both cases. Import was not affected by high concentrations of the antifolate drugs pyrimethamine and sulfadoxine, but was inhibited by the close folate analogue methotrexate. The pH optimum for folate uptake into infected erythrocytes was 6.5-7.0. Dinitrophenol and nigericin, which strongly facilitate the equilibration of H(+) ions across biological membranes and thus abolish or substantially reduce the proton gradient, inhibited folate uptake profoundly. The ATPase inhibitor concanamycin A also greatly reduced folate uptake, further demonstrating a link to ATP-powered proton transport. These data strongly suggest that the principal folate uptake pathway in P. falciparum is specific, highly regulated, dependent upon the proton gradient across the parasite plasma membrane, and is likely to be mediated by one or more proton symporters.

  20. Contribution of inflammasome genetics in Plasmodium vivax malaria.

    PubMed

    Santos, Marina L S; Reis, Edione Cristina; Bricher, Pamela N; Sousa, Tais N; Brito, Cristiana F A; Lacerda, Marcus V G; Fontes, Cor J F; Carvalho, Luzia H; Pontillo, Alessandra

    2016-06-01

    Recent reports showed that, in mice, symptomatic Plasmodium infection triggers NLRP3/NLRP12-dependent inflammasome formation and caspase-1 activation in monocytes. In humans, few works demonstrated that inflammasome is activated in malaria. As Plasmodiumvivax is a potent inducer of inflammatory response we hypothesised that inflammasome genetics might affect P. vivax malaria clinical presentation. For this purpose, selected SNPs in inflammasome genes were analysed among patients with symptomatic P. vivax malaria. 157 Brazilian Amazon patients with P. vivax malaria were genotyped for 10 single nucleotide polymorphisms (SNPs) in inflammasome genes NLRP1, NLRP3, AIM2, CARD8, IL1B, IL18 and MEFV. Effect of SNPs on hematologic and clinical parameters was analysed by multivariate analysis. Our data suggested an important role of NLRP1 inflammasome receptor in shaping the clinical presentation of P. vivax malaria, in term of presence of fever, anaemia and thrombocytopenia. Moreover IL1B rs1143634 resulted significantly associated to patients' parasitaemia, while IL18 rs5744256 plays a protective role against the development of anaemia. Polymorphisms in inflammasome genes could affect one or other aspects of malaria pathogenesis. Moreover, these data reveal novel aspects of P.vivax/host interaction that involved NLRP1-inflammasome.

  1. Comparative genomics of the neglected human malaria parasite Plasmodium vivax

    PubMed Central

    Carlton, Jane M.; Adams, John H.; Silva, Joana C.; Bidwell, Shelby L.; Lorenzi, Hernan; Caler, Elisabet; Crabtree, Jonathan; Angiuoli, Samuel V.; Merino, Emilio F.; Amedeo, Paolo; Cheng, Qin; Coulson, Richard M. R.; Crabb, Brendan S.; del Portillo, Hernando A.; Essien, Kobby; Feldblyum, Tamara V.; Fernandez-Becerra, Carmen; Gilson, Paul R.; Gueye, Amy H.; Guo, Xiang; Kang’a, Simon; Kooij, Taco W. A.; Korsinczky, Michael; Meyer, Esmeralda V.-S.; Nene, Vish; Paulsen, Ian; White, Owen; Ralph, Stuart A.; Ren, Qinghu; Sargeant, Tobias J.; Salzberg, Steven L.; Stoeckert, Christian J.; Sullivan, Steven A.; Yamamoto, Marcio Massao; Hoffman, Stephen L.; Wortman, Jennifer R.; Gardner, Malcolm J.; Galinski, Mary R.; Barnwell, John W.; Fraser-Liggett, Claire M.

    2008-01-01

    The human malaria parasite Plasmodium vivax is responsible for 25-40% of the ~515 million annual cases of malaria worldwide. Although seldom fatal, the parasite elicits severe and incapacitating clinical symptoms and often relapses months after a primary infection has cleared. Despite its importance as a major human pathogen, P. vivax is little studied because it cannot be propagated in the laboratory except in non-human primates. We determined the genome sequence of P. vivax in order to shed light on its distinctive biologic features, and as a means to drive development of new drugs and vaccines. Here we describe the synteny and isochore structure of P. vivax chromosomes, and show that the parasite resembles other malaria parasites in gene content and metabolic potential, but possesses novel gene families and potential alternate invasion pathways not recognized previously. Completion of the P. vivax genome provides the scientific community with a valuable resource that can be used to advance scientific investigation into this neglected species. PMID:18843361

  2. The Dynamics of Naturally Acquired Immunity to Plasmodium falciparum Infection

    PubMed Central

    Pinkevych, Mykola; Petravic, Janka; Chelimo, Kiprotich; Kazura, James W.; Moormann, Ann M.; Davenport, Miles P.

    2012-01-01

    Severe malaria occurs predominantly in young children and immunity to clinical disease is associated with cumulative exposure in holoendemic settings. The relative contribution of immunity against various stages of the parasite life cycle that results in controlling infection and limiting disease is not well understood. Here we analyse the dynamics of Plasmodium falciparum malaria infection after treatment in a cohort of 197 healthy study participants of different ages in order to model naturally acquired immunity. We find that both delayed time-to-infection and reductions in asymptomatic parasitaemias in older age groups can be explained by immunity that reduces the growth of blood stage as opposed to liver stage parasites. We found that this mechanism would require at least two components – a rapidly acting strain-specific component, as well as a slowly acquired cross-reactive or general immunity to all strains. Analysis and modelling of malaria infection dynamics and naturally acquired immunity with age provides important insights into what mechanisms of immune control may be harnessed by malaria vaccine strategists. PMID:23093922

  3. MEIOTIC RECOMBINATION, CROSS-REACTIVITY, AND PERSISTENCE IN PLASMODIUM FALCIPARUM