Medicine and Health Sciences Commons^™

Preclinical Characterization And Target Validation Of The Antimalarial Pantothenamide Mmv693183., Laura E. De Vries, Patrick A. M. Jansen, Catalina Barcelo, Justin Munro, Julie M. J. Verhoef, Charisse Flerida A. Pasaje, Kelly Rubiano, Josefine Striepen, Nada Abla, Luuk Berning, Judith M. Bolscher, Claudia Demarta-Gatsi, Rob W. M. Henderson, Tonnie Huijs, Karin M J Koolen, Patrick K. Tumwebaze, Tomas Yeo, Anna C. C. Aguiar, Iñigo Angulo-Barturen, Alisje Churchyard, Jake Baum, Benigno Crespo Fernández, Aline Fuchs, Francisco-Javier Gamo, Rafael V. C. Guido, María Belén Jiménez-Diaz, Dhelio B. Pereira, Rosemary Rochford, Camille Roesch, Laura M. Sanz, Graham Trevitt, Benoit Witkowski, Sergio Wittlin, Roland A. Cooper, Philip J. Rosenthal, Robert W. Sauerwein, Joost Schalkwijk, Pedro H. H. Hermkens, Roger V. Bonnert, Brice Campo, David A. Fidock, Manuel Llinás, Jacquin C. Niles, Taco W. A. Kooij, Koen J. Dechering

Natural Sciences and Mathematics | Faculty Scholarship

Drug resistance and a dire lack of transmission-blocking antimalarials hamper malaria elimination. Here, we present the pantothenamide MMV693183 as a first-in-class acetyl-CoA synthetase (AcAS) inhibitor to enter preclinical development. Our studies demonstrate attractive drug-like properties and in vivo efficacy in a humanized mouse model of Plasmodium falciparum infection. The compound shows single digit nanomolar in vitro activity against P. falciparum and P. vivax clinical isolates, and potently blocks P. falciparum transmission to Anopheles mosquitoes. Genetic and biochemical studies identify AcAS as the target of the MMV693183-derived antimetabolite, CoA-MMV693183. Pharmacokinetic-pharmacodynamic modelling predict that a single 30 mg oral dose is sufficient …

Discovery And Preclinical Pharmacology Of Ine963, A Potent And Fast-Acting Blood-Stage Antimalarial With A High Barrier To Resistance And Potential For Single-Dose Cures In Uncomplicated Malaria., Benjamin R. Taft, Fumiaki Yokokawa, Tom Kirrane, Anne-Catherine Mata, Richard Huang, Nicole Blaquiere, Grace Waldron, Bin Zou, Oliver Simon, Subramanyam Vankadara, Wai Ling Chan, Mei Ding, Sandra Sim, Judith Straimer, Armand Guiguemde, Suresh B Lakshminarayana, Jay Prakash Jain, Christopher Bodenreider, Christopher Thompson, Christian Lanshoeft, Wei Shu, Eric Fang, Jafri Qumber, Katherine Chan, Luying Pei, Yen-Liang Chen, Hanna Schulz, Jessie Lim, Siti Nurdiana Abas, Xiaoman Ang, Yugang Liu, Iñigo Angulo-Barturen, María Belén Jiménez-Díaz, Glaxosmithkline Gamo, Benigno Crespo-Fernandez, Philip J. Rosenthal, Roland A. Cooper, Patrick Tumwebaze, Anna Caroline Campos Aguiar, Brice Campo, Simon Campbell, Jürgen Wagner, Thierry T Diagana, Christopher Sarko

Natural Sciences and Mathematics | Faculty Scholarship

A series of 5-aryl-2-amino-imidazothiadiazole (ITD) derivatives were identified by a phenotype-based high-throughput screening using a blood stage Plasmodium falciparum (Pf) growth inhibition assay. A lead optimization program focused on improving antiplasmodium potency, selectivity against human kinases, and absorption, distribution, metabolism, excretion, and toxicity properties and extended pharmacological profiles culminated in the identification of INE963 (1), which demonstrates potent cellular activity against Pf 3D7 (EC50 = 0.006 μM) and achieves "artemisinin-like" kill kinetics in vitro with a parasite clearance time of/kg is fully curative in the Pf-humanized severe combined immunodeficient mouse model. INE963 (1) also exhibits a high barrier to resistance …

Can Repurposing Drugs Play A Role In Malaria Control?, Roland A. Cooper, Laura Kirkman

Natural Sciences and Mathematics | Faculty Scholarship

Innovative drug treatments for malaria, optimally with novel targets, are needed to combat the threat of parasite drug resistance. As drug development efforts continue, there may be a role for a host-targeting, repurposed cancer drug administered together with an artemisinin combination therapy that was shown to improve the speed of recovery from a malaria infection.

Associations Between Varied Susceptibilities To Pfatp4 Inhibitors And Genotypes In Ugandan Plasmodium Falciparum Isolates., Oriana Kreutzfeld, Stephanie A. Rasmussen, Aarti A. Ramanathan, Patrick K. Tumwebaze, Oswald Byaruhanga, Thomas Katairo, Victor Asua, Martin Okitwi, Stephen Orena, Jennifer Legac, Melissa D. Conrad, Samuel L. Nsobya, Ozkan Aydemir, Jeffrey Bailey, Maelle Duffey, Brett R. Bayles, Akhil B. Vaidya, Roland A. Cooper, Philip J. Rosenthal

Natural Sciences and Mathematics | Faculty Scholarship

Among novel compounds under recent investigation as potential new antimalarial drugs are three independently developed inhibitors of the Plasmodium falciparum P-type ATPase (PfATP4): KAE609 (cipargamin), PA92, and SJ733. We assessed ex vivo susceptibilities to these compounds of 374 fresh P. falciparum isolates collected in Tororo and Busia districts, Uganda, from 2016 to 2019. Median IC50s were 65 nM for SJ733, 9.1 nM for PA92, and 0.5 nM for KAE609. Sequencing of pfatp4 for 218 of these isolates demonstrated many nonsynonymous single nucleotide polymorphisms; the most frequent mutations were G1128R (69% of isolates mixed or mutant), Q1081K/R (68%), G223S (25%), N1045K …

Drug Susceptibility Of Plasmodium Falciparum In Eastern Uganda: A Longitudinal Phenotypic And Genotypic Study, Patrick K. Tumwebaze, Thomas Katairo, Martin Okitwi, Oswald Byaruhanga, Stephen Orena, Victor Asua, Marvin Duvalsaint, Jennifer Legac, Sevil Chelebieva, Frida G. Ceja, Stephanie A. Rasmussen, Melissa D. Conrad, Samuel L. Nsobya, Ozkan Aydemir, Jeffrey A. Bailey, Brett R. Bayles, Philip J. Rosenthal, Roland A. Cooper

Natural Sciences and Mathematics | Faculty Scholarship

Background: Treatment and control of malaria depends on artemisinin-based combination therapies (ACTs) and is challenged by drug resistance, but thus far resistance to artemisinins and partner drugs has primarily occurred in southeast Asia. The aim of this study was to characterise antimalarial drug susceptibility of Plasmodium falciparum isolates from Tororo and Busia districts in Uganda.

Methods: In this prospective longitudinal study, P falciparum isolates were collected from patients aged 6 months or older presenting at the Tororo District Hospital (Tororo district, a site with relatively low malaria incidence) or Masafu General Hospital (Busia district, a high-incidence site) in eastern Uganda …

The Antimalarial Mmv688533 Provides Potential For Single-Dose Cures With A High Barrier To, James M. Murithi, Cécile Pascal, Jade Bath, Xavier Boulenc, Nina F. Gnädig, Charisse Flerida A. Pasaje, Kelly Rubiano, Tomas Yeo, Sachel Mok, Sylvie Klieber, Paul Desert, María Belén Jiménez-Díaz, Jutta Marfurt, Mélanie Rouillier, Mohammed H. Cherkaoui-Rbati, Nathalie Gobeau, Sergio Wittlin, Anne-Catrin Uhlemann, Ric N. Price, Grennady Wirjanata, Rintis Noviyanti, Patrick K. Tumwebaze, Roland A. Cooper, Philip J. Rosenthal, Laura M. Sanz, Francisco-Javier Gamo, Jayan Joseph, Shivendra Singh, Sridevi Bashyam, Jean Michel Augereau, Elie Giraud, Tanguy Bozec, Thierry Vermat, Gilles Tuffal, Jean-Michel Guillon, Jérôme Menegotto, Laurent Sallé, Guillaume Louit, Marie-José Cabanis, Marie Françoise Nicolas, Michel Doubovetzky, Rita Merino, Nadir Bessila, Iñigo Angulo-Barturen, Delphine Baud, Lidiya Bebrevska, Fanny Escudié, Jacquin C. Niles, Benjamin Blasco, Simon Campbell, Gilles Courtemanche, Laurent Fraisse, Alain Pellet, David A. Fidock, Didier Leroy

Natural Sciences and Mathematics | Faculty Scholarship

The emergence and spread of Plasmodium falciparum resistance to first-line antimalarials creates an imperative to identify and develop potent preclinical candidates with distinct modes of action. Here, we report the identification of MMV688533, an acylguanidine that was developed following a whole-cell screen with compounds known to hit high-value targets in human cells. MMV688533 displays fast parasite clearance in vitro and is not cross-resistant with known antimalarials. In a P. falciparum NSG mouse model, MMV688533 displays a long-lasting pharmacokinetic profile and excellent safety. Selection studies reveal a low propensity for resistance, with modest loss of potency mediated by point mutations in …

The Antimalarial Mmv688533 Provides Potential For Single-Dose Cures With A High Barrier To, James M. Murithi, Cécile Pascal, Jade Bath, Xavier Boulenc, Nina F. Gnädig, Charisse Flerida A. Pasaje, Kelly Rubiano, Tomas Yeo, Sachel Mok, Sylvie Klieber, Paul Desert, María Belén Jiménez-Díaz, Jutta Marfurt, Mélanie Rouillier, Mohammed H. Cherkaoui-Rbati, Nathalie Gobeau, Sergio Wittlin, Anne-Catrin Uhlemann, Ric N. Price, Grennady Wirjanata, Rintis Noviyanti, Patrick Tumwebaze, Roland A. Cooper, Philip J. Rosenthal, Laura M. Sanz, Francisco-Javier Gamo, Jayan Joseph, Shivendra Singh, Sridevi Bashyam, Jean Michel Augereau, Elie Giraud, Tanguy Bozec, Thierry Vermat, Gilles Tuffal, Jean-Michel Guillon, Jérôme Menegotto, Laurent Sallé, Guillaume Louit, Marie-José Cabanis, Marie Françoise Nicolas, Michel Doubovetzky, Rita Merino, Nadir Bessila, Iñigo Angulo-Barturen, Delphine Baud, Lidiya Bebrevska, Fanny Escudié, Jacquin C. Niles, Benjamin Blasco, Simon Campbell, Gilles Courtemanche, Laurent Fraisse, Alain Pellet, David A. Fidock, Didier Leroy

Natural Sciences and Mathematics | Faculty Scholarship

The emergence and spread of Plasmodium falciparum resistance to first-line antimalarials creates an imperative to identify and develop potent preclinical candidates with distinct modes of action. Here, we report the identification of MMV688533, an acylguanidine that was developed following a whole-cell screen with compounds known to hit high-value targets in human cells. MMV688533 displays fast parasite clearance in vitro and is not cross-resistant with known antimalarials. In a P. falciparum NSG mouse model, MMV688533 displays a long-lasting pharmacokinetic profile and excellent safety. Selection studies reveal a low propensity for resistance, with modest loss of potency mediated by point mutations in …

Private Sector Role, Readiness And Performance For Malaria Case Management In Uganda, 2015., Kathryn A. O'Connell, Vamsi Vasireddy, Megan Littrell, Andria Rusk, Actwatch Group, Henry Kaula, Peter Buyungo, Jimmy Opigo

Collected Faculty and Staff Scholarship

BACKGROUND: Several interventions have been put in place to promote access to quality malaria case management services in Uganda's private sector, where most people seek treatment. This paper describes evidence using a mixed-method approach to examine the role, readiness and performance of private providers at a national level in Uganda. These data will be useful to inform strategies and policies for improving malaria case management in the private sector.

METHODS: The ACTwatch national anti-malarial outlet survey was conducted concurrently with a fever case management study. The ACTwatch nationally representative anti-malarial outlet survey was conducted in Uganda between May 18th 2015 …

Testing Times: Trends In Availability, Price, And Market Share Of Malaria Diagnostics In The Public And Private Healthcare Sector Across Eight Sub-Saharan African Countries From 2009 To 2015., Kathryn A. O'Connell, Vamsi Vasireddy, Megan Littrell, Andria Rusk, Actwatch Group, Kara Hanson, Catherine Goodman

Collected Faculty and Staff Scholarship

BACKGROUND: The World Health Organization guidelines have recommended that all cases of suspected malaria should receive a confirmatory test with microscopy or a malaria rapid diagnostic test (RDT), however evidence from sub-Saharan Africa (SSA) illustrates that only one-third of children under five with a recent fever received a test. The aim of this study was to evaluate availability, price and market share of microscopy and RDT from 2009/11 to 2014/15 in 8 SSA countries, to better understand barriers to improving access to malaria confirmatory testing in the public and private health sectors.

RESULTS: Repeated national cross-sectional quantitative surveys were conducted …

A Variant Pfcrt Isoform Can Contribute To Plasmodium Falciparum Resistance To The First-Line Partner Drug Piperaquine, Satish K. Dhingra, Devasha Redhi, Jill M. Combrinck, Tomas Yeo, John Okombo, Philipp P. Henrich, Ann N. Cowell, Purva Gupta, Matthew L. Stegman, Jonathan M. Hoke, Roland A. Cooper, Elizabeth Winzeler, Sachel Mok, Timothy J. Egan, David A. Fidock

Collected Faculty and Staff Scholarship

Current efforts to reduce the global burden of malaria are threatened by the rapid spread throughout Asia of Plasmodium falciparum resistance to artemisininbased combination therapies, which includes increasing rates of clinical failure with dihydroartemisinin plus piperaquine (PPQ) in Cambodia. Using zinc finger nucleasebased gene editing, we report that addition of the C101F mutation to the chloroquine (CQ) resistance-conferring PfCRT Dd2 isoform common to Asia can confer PPQ resistance to cultured parasites. Resistance was demonstrated as significantly higher PPQ concentrations causing 90% inhibition of parasite growth (IC90) or 50% parasite killing (50% lethal dose [LD50]). This mutation also reversed Dd2-mediated CQ …

Private Sector Opportunities And Threats To Achieving Malaria Elimination In The Greater Mekong Subregion: Results From Malaria Outlet Surveys In Cambodia, The Lao Pdr, Myanmar, And Thailand., Kathryn A. O'Connell, Vamsi Vasireddy, Megan Littrell, Andria Rusk, Actwatch Group, Sochea Phok, Saysana Phanalasy, Si Thu Thein, Asawin Likhitsup

Collected Faculty and Staff Scholarship

BACKGROUND: The aim of this paper is to review multi-country evidence of private sector adherence to national regulations, guidelines, and quality-assurance standards for malaria case management and to document current coverage of private sector engagement and support through ACTwatch outlet surveys implemented in 2015 and 2016.

RESULTS: Over 76,168 outlets were screened, and approximately 6500 interviews were conducted (Cambodia, N = 1303; the Lao People's Democratic Republic (PDR), N = 724; Myanmar, N = 4395; and Thailand, N = 74). There was diversity in the types of private sector outlets providing malaria treatment across countries, and the extent to which …

The Malaria Testing And Treatment Landscape In Benin., Kathryn A. O'Connell, Vamsi Vasireddy, Megan Littrell, Andria Rusk, Actwatch Group, Cyprien Zinsou, Adjibabi Bello Cherifath

Collected Faculty and Staff Scholarship

BACKGROUND: Since 2004, artemisinin-based combination therapy (ACT) has been the first-line treatment for uncomplicated malaria in Benin. In 2016, a medicine outlet survey was implemented to investigate the availability, price, and market share of anti-malarial treatment and malaria diagnostics. Results provide a timely and important benchmark to measure future interventions aimed at increasing access to quality malaria case management services.

METHODS: Between July 5th to August 6th 2016, a cross sectional, nationally-representative malaria outlet survey was conducted in Benin. A census of all public and private outlets with potential to distribute malaria testing and/or treatment was implemented among 30 clusters …

Anti-Malarial Landscape In Myanmar: Results From A Nationally Representative Survey Among Community Health Workers And The Private Sector Outlets In 2015/2016., Kathryn A. O'Connell, Vamsi Vasireddy, Megan Littrell, Andria Rusk, Actwatch Group, Si Thu Thein, Hnin Su Su Khin, Aung Thi

Collected Faculty and Staff Scholarship

BACKGROUND: In 2015/2016, an ACTwatch outlet survey was implemented to assess the anti-malarial and malaria testing landscape in Myanmar across four domains (Eastern, Central, Coastal, Western regions). Indicators provide an important benchmark to guide Myanmar's new National Strategic Plan to eliminate malaria by 2030.

METHODS: This was a cross-sectional survey, which employed stratified cluster-random sampling across four regions in Myanmar. A census of community health workers (CHWs) and private outlets with potential to distribute malaria testing and/or treatment was conducted. An audit was completed for all anti-malarials, malaria rapid diagnostic tests.

RESULTS: A total of 28,664 outlets were approached and …

Evidence On Anti-Malarial And Diagnostic Markets In Cambodia To Guide Malaria Elimination Strategies And Policies, Kathryn A. O'Connell, Vamsi Vasireddy, Megan Littrell, Andria Rusk, Actwatch Group, Sochea Phok, Dysoley Lek

Collected Faculty and Staff Scholarship

BACKGROUND: Understanding Cambodia's anti-malarial and diagnostic landscape in 2015 is critical for informing and monitoring strategies and policies as Cambodia moves forward with national efforts to eliminate malaria. The aim of this paper is to present timely and key findings on the public and private sector anti-malarial and diagnostic landscape in Cambodia. This evidence can serve as a baseline benchmark for guiding implementation of national strategies as well as other regional initiatives to address malaria elimination activities.

METHODS: From August 17th to October 1st, 2015, a cross sectional, nationally-representative malaria outlet survey was conducted in Cambodia. A census of all …

What Happened To Anti-Malarial Markets After The Affordable Medicines Facility-Malaria Pilot? Trends In Act Availability, Price And Market Share From Five African Countries Under Continuation Of The Private Sector Co-Payment Mechanism., Kathryn A. O'Connell, Vamsi Vasireddy, Megan Littrell, Andria Rusk, Actwatch Group, Sarah Tougher, Kara Hanson, Catherine Goodman

Collected Faculty and Staff Scholarship

BACKGROUND: The private sector supplies anti-malarial treatment for large proportions of patients in sub-Saharan Africa. Following the large-scale piloting of the Affordable Medicines Facility-malaria (AMFm) from 2010 to 2011, a private sector co-payment mechanism (CPM) provided continuation of private sector subsidies for quality-assured artemisinin combination therapies (QAACT). This article analyses for the first time the extent to which improvements in private sector QAACT supply and distribution observed during the AMFm were maintained or intensified during continuation of the CPM through 2015 in Kenya, Madagascar, Nigeria, Tanzania and Uganda using repeat cross-sectional outlet survey data.

RESULTS: QAACT market share in all …

Insights Into The Availability And Distribution Of Oral Artemisinin Monotherapy In Myanmar: Evidence From A Nationally Representative Outlet Survey., Kathryn A. O'Connell, Vamsi Vasireddy, Megan Littrell, Andria Rusk, Actwatch Group, Si Thu Thein, Hnin Su Su Khin, Aung Thi

Collected Faculty and Staff Scholarship

BACKGROUND: The containment of artemisinin resistance in Myanmar, historically an important probable origin and route of anti-malarial resistance to the India sub-continent and beyond, is crucial to global malaria control and elimination. This paper describes what is currently known about the sale and distribution of oral artemisinin monotherapy (AMT) across Myanmar, where this medicine is commonly found.

METHODS: A nationally representative 2015 outlet survey was conducted in the private sector, and among community health workers across four geographical domains. A national sample of outlets was screened for availability of malaria testing and treatment, and an audit was completed for all …

The Malaria Testing And Treatment Landscape In Mainland Tanzania, 2016., Kathryn A. O'Connell, Vamsi Vasireddy, Megan Littrell, Andria Rusk, Actwatch Group, Daniel Michael, Sigsbert Patila Mkunde

Collected Faculty and Staff Scholarship

BACKGROUND: Understanding the key characteristics of malaria testing and treatment is essential to the control of a disease that continues to pose a major risk of morbidity and mortality in mainland Tanzania, with evidence of a resurgence of the disease in recent years. The introduction of artemisinin combination therapy (ACT) as the first-line treatment for malaria, alongside policies to promote rational case management following testing, highlights the need for evidence of anti-malarial and testing markets in the country. The results of the most recent mainland Tanzania ACTwatch outlet survey are presented here, including data on the availability, market share and …

Geographically-Weighted Regression Of Knowledge And Behaviour Determinants To Anti-Malarial Recommending And Dispensing Practice Among Medicine Retailers In Western Kenya: Capacitating Targeted Interventions, Andria Rusk, Linda Highfield, J. Michael Wilkerson, Melissa Harrell, Andrew Obala, Benjamin Amick

Collected Faculty and Staff Scholarship

Background

Most patients with malaria seek treatment first in retail drug shops. Myriad studies have examined retailer behaviours and characteristics to understand the determinants to these behaviours. Geospatial methods are helpful in discovering if geographic location plays a role in the relationship between determinants and outcomes. This study aimed to discover if spatial autocorrelation exists in the relationship between determinants and retailer behaviours, and to provide specific geographic locations and target behaviours for tailoring future interventions.

Methods

Retailer behaviours and characteristics captured from a survey deployed to medicine retailers in the Webuye Demographic and Health Surveillance Site were analysed using …

Lack Of Resistance Of Plasmodium Falciparum To Dihydroartemisinin In Uganda Based On Parasitogolgical And Molecular Assays, Roland A. Cooper, Melissa D. Conrad, Quentin D. Watson, Stephanie J. Huezo, Harriet Ninsiima, Patrick Tumwebaze, Samuel L. Nsobya, Philip J. Rosenthal

Collected Faculty and Staff Scholarship

• Artemisinin-­‐based combination therapy is now standard treatment for falciparum malaria. However, this regimen is threatened by resistance to artemisinins, manifest as delayed clearance of parasitemia after therapy, in southeast Asia.

• Artemisinin resistance in southeast Asia is associated with increased parasitemias in culture, compared to those in sensi0ve parasites, 72 hours a=er a 6 hour pulse with 700 nM dihydroartemisinin (DHA), and with propeller domain polymorphisms in the Plasmodium falciparum kelch (K13; PF3D7_1343700) gene

• Given that artemether/lumefantrine has been adopted as standard therapy for malaria within the last decade in Uganda, we characterized artemisinin sensiBvity in fresh P. falciparum isolates from …

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Investigation Of Dual Stage Acridones As A Potent Malaria Treatment, Stephanie Huezo

Dissertations, Masters Theses, Capstones, and Culminating Projects

The need for potent antimalarials to prevent the emergence of drug resistant Plasmodium falciparum is urgent. Discovery of novel acridone chemotypes have shown promise for a new antimalarial drug treatment. Presently, two acridone chemotypes have intrinsic antimalarial potency against chloroquine sensitive and multidrug resistant parasites. Acridones lacking an N10 side chain are known as chemotype I acridones, whereas, chemotype II acridones are defined as having an alkyl side chain at the same position. The N10 substitution of chemotype II acridones is thought to target heme and inhibit hemozoin formation within the parasite’s digestive vacuole, and is known to provide synergistic …

Impact Of Antimalarial Treatment And Chemoprevention On The Drug Sensitivity Of Malaria Parasites Isolated From Ugandan Children, Patrick Tumwebaze, Melissa D. Conrad, Andrew Walakira, Norbert Leclair, Oswald Byaruhanga, Christine Nakazibwe, Benjamin Kozak, Jessica Bloome, Jaffer Okiring, Abel Kakuru, Victor Bigira, James Kapisi, Jennifer Legac, Jiri Gut, Roland A. Cooper, Moses R. Kamya, Diane V. Havlir, Grant Dorsey, Bryan Greenhouse, Samuel L. Nsobya, Philip J. Rosenthal

Collected Faculty and Staff Scholarship

Changing treatment practices may be selecting for changes in the drug sensitivity of malaria parasites. We characterized ex vivo drug sensitivity and parasite polymorphisms associated with sensitivity in 459 Plasmodium falciparum samples obtained from subjects enrolled in two clinical trials in Tororo, Uganda, from 2010 to 2013. Sensitivities to chloroquine and monodesethylamodiaquine varied widely; sensitivities to quinine, dihydroartemisinin, lumefantrine, and piperaquine were generally good. Associations between ex vivo drug sensitivity and parasite polymorphisms included decreased chloroquine and monodesethylamodiaquine sensitivity and increased lumefantrine and piperaquine sensitivity with pfcrt 76T, as well as increased lumefantrine sensitivity with pfmdr1 86Y, Y184, and 1246Y. …

Expanding Access To Malaria Diagnosis Through Retail Shops In Western Kenya: What Do Shop Workers Think?, Andria Rusk, Catherine Goodman, Violet Naanyu, Beatrice Koech, Andrew Obala, Wendy Prudhomme O'Meara

Collected Faculty and Staff Scholarship

Background. The common symptoms of malaria reduce the specificity of clinical diagnosis. Presumptive treatment is conventional but can lead to overdiagnosis of malaria, delay of appropriate treatment, overprescription of antimalarials, and drug resistance. Routine use of diagnostic tests can address many of these concerns. Though treatment is often procured from retailers, there is low availability of rapid diagnostic tests for malaria (MRDTs), a simple, inexpensive, and accurate diagnostic solution. We know little about the challenges to expanding access to diagnostics through these outlets. Methods. To understand the perceptions of the benefits and challenges to selling rapid diagnostic tests for malaria, …

Mutation In The Plasmodium Falciparum Crt Protein Determines The Stereospecific Activity Of Antimalarial Cinchona Alkaloids, Carol E. Griffin, Jonathan M. Hoke, Upeka Samarakoon, Junhui Duan, Jianbing Mu, Michael T. Ferdig, David C. Warhurst, Roland Cooper

Collected Faculty and Staff Scholarship

The Cinchona alkaloids are quinoline aminoalcohols that occur as diastereomer pairs, typified by (-)-quinine and (+)-quinidine. The potency of (+)-isomers is greater than the (-)-isomers in vitro and in vivo against Plasmodium falciparum malaria parasites. They may act by the inhibition of heme crystallization within the parasite digestive vacuole in a manner similar to chloroquine. Earlier studies showed that a K76I mutation in the digestive vacuole-associated protein, PfCRT (P. falciparum chloroquine resistance transporter), reversed the normal potency order of quinine and quinidine toward P. falciparum. To further explore PfCRT-alkaloid interactions in the malaria parasite, we measured the in vitro susceptibility …

Chloroquine Susceptibility And Reversibility In A Plasmodium Falciparum Genetic Cross, Jigar J. Patel, Drew Thacker, Jon C. Tan, Perri Pleeter, Lisa Checkley, Joseph M. Gonzales, Bingbing Deng, Paul D. Roepe, Roland A. Cooper, Michael T. Ferdig

Collected Faculty and Staff Scholarship

Mutations in the Plasmodium falciparum chloroquine (CQ) resistance transporter (PfCRT), are major determinants of verapamil (VP)-reversible CQ resistance (CQR). In the presence of mutant PfCRT, additional genes contribute to the wide range of CQ susceptibilities observed. It is not known if these genes influence mechanisms of chemosensitization by CQR reversal agents. Using quantitative trait locus (QTL) mapping of progeny clones from the HB3 × Dd2 cross, we show that the P. falciparum multidrug resistance gene 1 (pfmdr1) interacts with the Southeast Asiaderived mutant pfcrt haplotype to modulate CQR levels. A novel chromosome 7 locus is predicted to contribute with the …