Read by QxMD icon Read

falciparum polymorphism

Eric P M Grist, Jennifer A Flegg, Georgina Humphreys, Ignacio Suay Mas, Tim J C Anderson, Elizabeth A Ashley, Nicholas P J Day, Mehul Dhorda, Arjen M Dondorp, M Abul Faiz, Peter W Gething, Tran T Hien, Tin M Hlaing, Mallika Imwong, Jean-Marie Kindermans, Richard J Maude, Mayfong Mayxay, Marina McDew-White, Didier Menard, Shalini Nair, Francois Nosten, Paul N Newton, Ric N Price, Sasithon Pukrittayakamee, Shannon Takala-Harrison, Frank Smithuis, Nhien T Nguyen, Kyaw M Tun, Nicholas J White, Benoit Witkowski, Charles J Woodrow, Rick M Fairhurst, Carol Hopkins Sibley, Philippe J Guerin
BACKGROUND: Artemisinin-resistant Plasmodium falciparum malaria parasites are now present across much of mainland Southeast Asia, where ongoing surveys are measuring and mapping their spatial distribution. These efforts require substantial resources. Here we propose a generic 'smart surveillance' methodology to identify optimal candidate sites for future sampling and thus map the distribution of artemisinin resistance most efficiently. METHODS: The approach uses the 'uncertainty' map generated iteratively by a geostatistical model to determine optimal locations for subsequent sampling...
October 24, 2016: International Journal of Health Geographics
Sittiporn Pattaradilokrat, Vorthon Sawaswong, Phumin Simpalipan, Morakot Kaewthamasorn, Napaporn Siripoon, Pongchai Harnyuttanakorn
BACKGROUND: An effective malaria vaccine is an urgently needed tool to fight against human malaria, the most deadly parasitic disease of humans. One promising candidate is the merozoite surface protein-3 (MSP-3) of Plasmodium falciparum. This antigenic protein, encoded by the merozoite surface protein (msp-3) gene, is polymorphic and classified according to size into the two allelic types of K1 and 3D7. A recent study revealed that both the K1 and 3D7 alleles co-circulated within P. falciparum populations in Thailand, but the extent of the sequence diversity and variation within each allelic type remains largely unknown...
October 21, 2016: Malaria Journal
Reyaud Rahman, Maria Jesus Sanchez Martin, Shamdeo Persaud, Nicolas Ceron, Dwayne Kellman, Lise Musset, Keith H Carter, Pascal Ringwald
Because of concerns about possible emergence of artemisinin resistance strains of Plasmodium falciparum in mining areas of the interior of Guyana, a 7-day artesunate trial was conducted from March to December 2014. The day-3 parasite clearance rate, the efficacy of artesunate at day 28, and polymorphism of Kelch 13 (PfK13)-the marker of artemisinin resistance-were assessed. The study confirmed the continued sensitivity of P falciparum to artemisinin. A 7-day course of artesunate was 100% efficacious with only 2% (95% confidence interval, ...
September 2016: Open Forum Infectious Diseases
Manuel E Patarroyo, Jorge Aza-Conde, Armando Moreno-Vranich, Laura Pabón, Yahson Varela, Manuel A Patarroyo
Like Thomas Hardy's famous novel Far from the Madding Crowd, Plasmodium falciparum parasites display their most relevant survival structures (proteins) involved in host cell invasion far away from the immune system's susceptible regions, displaying tremendous genetic variability, to attract the immune response and escape immune pressure. The 3D structure localisation of the conserved amino acid sequences of this deadly parasite's most relevant proteins involved in host cell invasion, as well as the location of the highly polymorphic, highly immunogenic regions, clearly demonstrates that such structures are far apart, sometimes 90° to 180° opposite, thereby rendering the immune response useless...
October 4, 2016: Current Issues in Molecular Biology
Bart W Faber, Stephan Hellwig, Sophie Houard, Nicolas Havelange, Jürgen Drossard, Hubert Mertens, Alexander Croon, Robin Kastilan, Richard Byrne, Nicole van der Werff, Marjolein van der Eijk, Alan W Thomas, Clemens H M Kocken, Edmond J Remarque
Plasmodium falciparum apical membrane antigen 1 (PfAMA1) is a leading asexual blood stage vaccine candidate for malaria. In preparation for clinical trials, three Diversity Covering (DiCo) PfAMA1 ectodomain proteins, designed to overcome the intrinsic polymorphism that is present in PfAMA1, were produced under Good Manufacturing Practice (GMP) in Pichia pastoris. Using identical methodology, the 3 strains were cultivated in 70-L scale fed-batch fermentations and PfAMA1-DiCos were purified by two chromatography steps, an ultrafiltration/diafiltration procedure and size exclusion chromatography, resulting in highly pure (>95%) PfAMA1-DiCo1, PfAMA1 DiCo2 and PfAMA1 DiCo3, with final yields of 1...
2016: PloS One
Zenglei Wang, Mynthia Cabrera, Jingyun Yang, Lili Yuan, Bhavna Gupta, Xiaoying Liang, Karen Kemirembe, Sony Shrestha, Awtum Brashear, Xiaolian Li, Stephen F Porcella, Jun Miao, Zhaoqing Yang, Xin-Zhuan Su, Liwang Cui
Drug resistance has emerged as one of the greatest challenges facing malaria control. The recent emergence of resistance to artemisinin (ART) and its partner drugs in ART-based combination therapies (ACT) is threatening the efficacy of this front-line regimen for treating Plasmodium falciparum parasites. Thus, an understanding of the molecular mechanisms that underlie the resistance to ART and the partner drugs has become a high priority for resistance containment and malaria management. Using genome-wide association studies, we investigated the associations of genome-wide single nucleotide polymorphisms with in vitro sensitivities to 10 commonly used antimalarial drugs in 94 P...
October 3, 2016: Scientific Reports
Bhavna Gupta, Daniel M Parker, Qi Fan, B P Niranjan Reddy, Guiyun Yan, Jetsumon Sattabongkot, Liwang Cui
Malaria transmission along international borders of the Greater Mekong Subregion is a big challenge for regional malaria elimination. At the Thai-Myanmar border, Plasmodium falciparum cases have dropped dramatically; however, increasing P. vivax prevalence and the emerging reports on hidden malaria burden due to asymptomatic infections demand attention. We conducted cross-sectional surveys to detect asymptomatic malaria infections in a small village located at Thai-Myanmar border and genotyped P. vivax infections in order to understand the level of genetic diversity on such a microgeographic scale...
September 28, 2016: Infection, Genetics and Evolution
Edward H Ntege, Nobuko Arisue, Daisuke Ito, Tomoyuki Hasegawa, Nirianne M Q Palacpac, Thomas G Egwang, Toshihiro Horii, Eizo Takashima, Takafumi Tsuboi
Genetic variability in Plasmodium falciparum malaria parasites hampers current malaria vaccine development efforts. Here, we hypothesize that to address the impact of genetic variability on vaccine efficacy in clinical trials, conserved antigen targets should be selected to achieve robust host immunity across multiple falciparum strains. Therefore, suitable vaccine antigens should be assessed for levels of polymorphism and genetic diversity. Using a total of one hundred and two clinical isolates from a region of high malaria transmission in Uganda, we analyzed extent of polymorphism and genetic diversity in four recently reported novel blood-stage malaria vaccine candidate proteins: Rh5 interacting protein (PfRipr), GPI anchored micronemal antigen (PfGAMA), rhoptry-associated leucine zipper-like protein 1 (PfRALP1) and Duffy binding-like merozoite surface protein 1 (PfMSPDBL1)...
September 28, 2016: Vaccine
Selorme Adukpo, Ben A Gyan, Michael F Ofori, Daniel Dodoo, Thirumalaisamy P Velavan, Christian G Meyer
BACKGROUND: Malaria elicits inflammatory responses, which, if not well regulated, may exert detrimental effects. When activated, triggering receptor expressed on myeloid cells (TREM)-1 enhances inflammatory responses by increasing secretion of IL-8 and other Th1 cytokines. In contrast, TREM-like transcript 1 (TREML-1) promotes anti-inflammatory responses by binding to TREM-1 ligands and competing with TREM-1, thus antagonizing TREM-1 activation to reduce inflammation. Endothelial protein C receptor (EPCR) also mediates anti-inflammatory responses by activating endothelial protein C (PC)...
September 27, 2016: Tropical Medicine & International Health: TM & IH
Anju Verma, Hema Joshi, Vineeta Singh, Anup Anvikar, Neena Valecha
BACKGROUND: Plasmodium vivax is the most widely distributed human malaria parasite and accounts for approximately the same number of malaria cases as Plasmodium falciparum in India. Compared with P. falciparum, P. vivax is difficult to eradicate because of its tendency to cause relapses, which impacts treatment and control strategies. The genetic diversity of these parasites, particularly of the merozoite surface protein-3 alpha (msp-3α) gene, can be used to help develop a potential vaccine...
2016: Malaria Journal
Damien R Drew, Danny W Wilson, Salenna R Elliott, Nadia Cross, Ulrich Terheggen, Anthony N Hodder, Peter M Siba, Kiprotich Chelimo, Arlene E Dent, James W Kazura, Ivo Mueller, James G Beeson
BACKGROUND: The polymorphic nature of many malaria vaccine candidates presents major challenges to achieving highly efficacious vaccines. Presently, there is very little knowledge on the prevalence and patterns of functional immune responses to polymorphic vaccine candidates in populations to guide vaccine design. A leading polymorphic vaccine candidate against blood-stage Plasmodium falciparum is apical membrane antigen 1 (AMA1), which is essential for erythrocyte invasion. The importance of AMA1 as a target of acquired human inhibitory antibodies, their allele specificity and prevalence in populations is unknown, but crucial for vaccine design...
September 23, 2016: BMC Medicine
Fredrick Kateera, Sam L Nsobya, Steven Tukwasibwe, Emmanuel Hakizimana, Leon Mutesa, Petra F Mens, Martin P Grobusch, Michèle van Vugt, Nirbhay Kumar
Faced with intense levels of chloroquine (CQ) resistance in Plasmodium falciparum malaria, Rwanda replaced CQ with amodiaquine (AQ)+sulfadoxine-pyrimethamine (SP) in 2001, and subsequently with artemether-lumefantrine (AL) in 2006, as first-line treatments for uncomplicated malaria. Following years of discontinuation of CQ use, re-emergence of CQ-susceptible parasites has been reported in countries including Malawi, Kenya and Tanzania. In contrast, high levels of SP resistant mutant parasites continue to be reported even in countries of presumed reduced SP drug selection pressure...
September 17, 2016: Acta Tropica
Jean Baptiste Roseau, Bruno Pradines, Nicolas Paleiron, Serge Vedy, Marylin Madamet, Fabrice Simon, Emilie Javelle
BACKGROUND: Artemisinin-based combination therapy (ACT) introduced in the mid-1990s has been recommended since 2005 by the World Health Organization as first-line treatment against Plasmodium falciparum in all endemic countries. In 2010, the combination dihydroartemisinin-piperaquine (DP) was recommended for the treatment of uncomplicated P. falciparum malaria. DP is one of the first-line treatments used by the French army since 2013. CASE PRESENTATION: A case of P...
2016: Malaria Journal
Lorna J Chebon, Bidii S Ngalah, Luicer A Ingasia, Dennis W Juma, Peninah Muiruri, Jelagat Cheruiyot, Benjamin Opot, Emmanuel Mbuba, Mabel Imbuga, Hoseah M Akala, Wallace Bulimo, Ben Andagalu, Edwin Kamau
Genetically determined artemisinin resistance in Plasmodium falciparum has been described in Southeast Asia. The relevance of recently described Kelch 13-propeller mutations for artemisinin resistance in Sub-Saharan Africa parasites is still unknown. Southeast Asia parasites have low genetic diversity compared to Sub-Saharan Africa, where parasites are highly genetically diverse. This study attempted to elucidate whether genetics provides a basis for discovering molecular markers in response to artemisinin drug treatment in P...
2016: PloS One
Sabina Dahlström Otienoburu, Oumou Maïga-Ascofaré, Birgit Schramm, Vincent Jullien, Joel J Jones, Yah M Zolia, Pascal Houzé, Elizabeth A Ashley, Jean-René Kiechel, Philippe J Guérin, Jacques Le Bras, Sandrine Houzé
BACKGROUND: Plasmodium falciparum uncomplicated malaria can successfully be treated with an artemisinin-based combination therapy (ACT). However resistance is spreading to the different ACT compounds; the artemisinin derivative and the partner drug. Studies of P. falciparum polymorphisms associated with drug resistance can provide a useful tool to track resistance and guide treatment policy as well as an in-depth understanding of the development and spread of resistance. METHODS: The role of P...
2016: Malaria Journal
Costanza Tacoli, Prabhanjan P Gai, Claude Bayingana, Kevin Sifft, Dominik Geus, Jules Ndoli, Augustin Sendegeya, Jean Bosco Gahutu, Frank P Mockenhaupt
Emerging artemisinin resistance is a threat to global malaria control. Mutations in the Plasmodium falciparum Kelch 13 (K13) propeller domain confer artemisinin resistance and constitute molecular markers for its detection and monitoring. We sequenced 222 P. falciparum isolates obtained from community children in the Huye District of southern Rwanda in 2010, 2014, and 2015 to investigate the presence of K13 polymorphisms. No polymorphisms were observed in 2010 but they were present in 2.5% and 4.5% in 2014 and 2015, respectively...
August 29, 2016: American Journal of Tropical Medicine and Hygiene
Moses Ocan, Freddie Bwanga, Alfred Okeng, Fred Katabazi, Edgar Kigozi, Samuel Kyobe, Jasper Ogwal-Okeng, Celestino Obua
BACKGROUND: In the absence of an effective vaccine, malaria treatment and eradication is still a challenge in most endemic areas globally. This is especially the case with the current reported emergence of resistance to artemisinin agents in Southeast Asia. This study therefore explored the prevalence of K13-propeller gene polymorphisms among Plasmodium falciparum parasites in northern Uganda. METHODS: Adult patients (≥18 years) presenting to out-patients department of Lira and Gulu regional referral hospitals in northern Uganda were randomly recruited...
2016: BMC Infectious Diseases
Alistair Miles, Zamin Iqbal, Paul Vauterin, Richard Pearson, Susana Campino, Michel Theron, Kelda Gould, Daniel Mead, Eleanor Drury, John O'Brien, Valentin Ruano Rubio, Bronwyn MacInnis, Jonathan Mwangi, Upeka Samarakoon, Lisa Ranford-Cartwright, Michael Ferdig, Karen Hayton, Xin-Zhuan Su, Thomas Wellems, Julian Rayner, Gil McVean, Dominic Kwiatkowski
The malaria parasite Plasmodium falciparum has a great capacity for evolutionary adaptation to evade host immunity and develop drug resistance. Current understanding of parasite evolution is impeded by the fact that a large fraction of the genome is either highly repetitive or highly variable and thus difficult to analyze using short-read sequencing technologies. Here, we describe a resource of deep sequencing data on parents and progeny from genetic crosses, which has enabled us to perform the first genome-wide, integrated analysis of SNP, indel and complex polymorphisms, using Mendelian error rates as an indicator of genotypic accuracy...
September 2016: Genome Research
Roméo Karl Imboumy-Limoukou, Sidney Maghendi-Nzondo, Charlene Lady Kouna, Lotfi Bounaadja, Sophie Mbang, Jean Claude Biteghe, Carole Eboumbou, Franck Prugnolle, Isabelle Florent, Jean-Bernard Lekana-Douki
Pf113 is a P. falciparum putatively GPI-anchored protein that has been so far localized at the surface of merozoites, suggesting it could interact with RBC surface during merozoite invasion. Previous studies conducted in Papua New Guinea and in Kenya have revealed that this protein is recognized by natural antibodies in individuals living in malaria-endemic areas and is associated with protective immunity in malaria, further supporting the potential of Pf113 for the development of anti-malaria vaccines. However, in Central Africa, no study on the immunogenicity of this protein has been conducted...
November 2016: Acta Tropica
Wahib M Atroosh, Hesham M Al-Mekhlafi, Adel Al-Jasari, Hany Sady, Salwa S Dawaki, Fatin N Elyana, Mona A Al-Areeqi, Nabil A Nasr, Awatif M Abdulsalam, Lahvanya R Subramaniam, Meram Azzani, Init Ithoi, Yee Ling Lau, Johari Surin
Introduction. Despite the efforts of the malaria control programme, malaria morbidity is still a common health problem in Yemen, with 60% of the population at risk. Plasmodium falciparum is responsible for 99% of malaria cases. The emergence in Yemen of parasite resistance to chloroquine (CQ) prompted the adoption of artemisinin combination therapy (ACT) in 2009, which involves the use of artesunate plus sulphadoxine-pyrimethamine (AS + SP). However, CQ was retained as the drug of choice for vivax malaria. To assess the impact of the change in the malaria treatment policy five years after its introduction, the present study investigated the mutations in the CQ resistance transporter (pfcrt) and multidrug resistance 1 (pfmdr1) genes...
2016: PeerJ
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"