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Ehrlich HY, Somé AF, Bazié T, Ebou CN, Dembélé EL, Balma R, Goodwin J, Wade M, Bei AK, Ouédraogo JB, Foy BD, Dabiré RK, Parikh S. Tracking antimalarial drug resistance using mosquito blood meals: a cross-sectional study. THE LANCET. MICROBE 2023; 4:e461-e469. [PMID: 37086737 PMCID: PMC10365133 DOI: 10.1016/s2666-5247(23)00063-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 02/06/2023] [Accepted: 02/07/2023] [Indexed: 04/24/2023]
Abstract
BACKGROUND Strong surveillance systems with wide geographic coverage are needed to detect and respond to reports of antimalarial drug resistance on the African continent. We aimed to assess the utility and feasibility of using blood-fed mosquitos (xenomonitoring) to conduct rapid surveillance of molecular markers associated with resistance in human populations. METHODS We conducted three cross-sectional surveys in two rainy seasons and the interim dry season in southwest Burkina Faso between Oct 10, 2018, and Sept 17, 2019. We collected human blood samples and blood-fed mosquitos residing in household clusters across seven village sectors. Samples were assessed for Plasmodium falciparum with ultrasensitive quantitative PCR, genotyped for two markers of reduced drug susceptibility, pfmdr1 256A>T (Asn86Tyr) and pfcrt 227A>C (Lys76Thr), and sequenced for four markers of clonality. We assessed statistical equivalence using a 10% margin of equivalence. FINDINGS We identified 551 infections in 1483 human blood samples (mean multiplicity of infection [MOI] 1·94, SD 1·47) and 346 infections in 2151 mosquito blood meals (mean MOI 2·2, SD 1·67). The frequency of pfmdr1 Asn86Tyr was 4% in survey 1, 2% in survey 2, and 12% in survey 3 in human samples, and 3% in survey 1, 0% in survey 2, and 8% in survey 3 in mosquito blood meals, and inter-host frequencies were statistically equivalent in surveys 1 and 2 (p<0·0001) but not Survey 3 (p=0·062) within a tolerability of 0·10. The frequency of pfcrt Lys76Thr was 16% in survey 1, 55% in survey 2, and 11% in survey 3 in humans and 40% in survey 1, 72% in survey 2, and 13% in survey 3 in mosquitos, and inter-host frequencies were equivalent in survey 3 only (p=0·032) within a tolerability of 0·10. In simulations, multiple but not preferential feeding behaviour in mosquitos reduced the accuracy of frequency estimates between hosts, particularly for markers circulating at higher frequencies. INTERPRETATION Molecular markers in mosquito blood meals and in humans exhibited similar temporal trends but frequencies were not statistically equivalent in all scenarios. More work is needed to determine empirical and pragmatic thresholds of difference. Xenomonitoring might be an efficient tool to provide rapid information on emerging antimalarial resistance in regions with insufficient surveillance. FUNDING National Institute of Allergy and Infectious Diseases. TRANSLATION For the French translation of the abstract see Supplementary Materials section.
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Affiliation(s)
- Hanna Y Ehrlich
- Department of Epidemiology of Microbial Diseases, Yale University, New Haven, CT, USA; One Health Institute, University of California, Davis, CA, USA.
| | - A Fabrice Somé
- Department of Parasitology, Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Thomas Bazié
- Department of Parasitology, Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Cathérine Neya Ebou
- Department of Parasitology, Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Estelle Lotio Dembélé
- Department of Parasitology, Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Richard Balma
- Department of Medical Entomology, Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Justin Goodwin
- Department of Epidemiology of Microbial Diseases, Yale University, New Haven, CT, USA
| | - Martina Wade
- Department of Epidemiology of Microbial Diseases, Yale University, New Haven, CT, USA
| | - Amy K Bei
- Department of Epidemiology of Microbial Diseases, Yale University, New Haven, CT, USA
| | - Jean-Bosco Ouédraogo
- Department of Epidemiology of Microbial Diseases, Yale University, New Haven, CT, USA; Department of Parasitology, Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Brian D Foy
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Roch K Dabiré
- Department of Medical Entomology, Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Sunil Parikh
- Department of Epidemiology of Microbial Diseases, Yale University, New Haven, CT, USA
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Nkya TE, Fillinger U, Sangoro OP, Marubu R, Chanda E, Mutero CM. Six decades of malaria vector control in southern Africa: a review of the entomological evidence-base. Malar J 2022; 21:279. [PMID: 36184603 PMCID: PMC9526912 DOI: 10.1186/s12936-022-04292-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 09/05/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Countries in the southern Africa region have set targets for malaria elimination between 2020 and 2030. Malaria vector control is among the key strategies being implemented to achieve this goal. This paper critically reviews published entomological research over the past six decades in three frontline malaria elimination countries namely, Botswana Eswatini and Namibia, and three second-line malaria elimination countries including Mozambique, Zambia, and Zimbabwe. The objective of the review is to assess the current knowledge and highlight gaps that need further research attention to strengthen evidence-based decision-making toward malaria elimination. METHODS Publications were searched on the PubMed engine using search terms: "(malaria vector control OR vector control OR malaria vector*) AND (Botswana OR Swaziland OR Eswatini OR Zambia OR Zimbabwe OR Mozambique)". Opinions, perspectives, reports, commentaries, retrospective analysis on secondary data protocols, policy briefs, and reviews were excluded. RESULTS The search resulted in 718 publications with 145 eligible and included in this review for the six countries generated over six decades. The majority (139) were from three countries, namely Zambia (59) and Mozambique (48), and Zimbabwe (32) whilst scientific publications were relatively scanty from front-line malaria elimination countries, such as Namibia (2), Botswana (10) and Eswatini (4). Most of the research reported in the publications focused on vector bionomics generated mostly from Mozambique and Zambia, while information on insecticide resistance was mostly available from Mozambique. Extreme gaps were identified in reporting the impact of vector control interventions, both on vectors and disease outcomes. The literature is particularly scanty on important issues such as change of vector ecology over time and space, intervention costs, and uptake of control interventions as well as insecticide resistance. CONCLUSIONS The review reveals a dearth of information about malaria vectors and their control, most noticeable among the frontline elimination countries: Namibia, Eswatini and Botswana. It is of paramount importance that malaria vector research capacity and routine entomological monitoring and evaluation are strengthened to enhance decision-making, considering changing vector bionomics and insecticide resistance, among other determinants of malaria vector control.
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Affiliation(s)
- Theresia Estomih Nkya
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- University of Dar es Salaam, Mbeya College of Health and Allied Sciences, Mbeya, Tanzania
| | - Ulrike Fillinger
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | | | - Rose Marubu
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Emmanuel Chanda
- World Health Organization-Regional Office for Africa, Brazzaville, Republic of Congo
| | - Clifford Maina Mutero
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
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Temporal trends in molecular markers of drug resistance in Plasmodium falciparum in human blood and profiles of corresponding resistant markers in mosquito oocysts in Asembo, western Kenya. Malar J 2022; 21:265. [PMID: 36100912 PMCID: PMC9472345 DOI: 10.1186/s12936-022-04284-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 08/30/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Over the last two decades, the scale-up of vector control and changes in the first-line anti-malarial, from chloroquine (CQ) to sulfadoxine-pyrimethamine (SP) and then to artemether-lumefantrine (AL), have resulted in significant decreases in malaria burden in western Kenya. This study evaluated the long-term effects of control interventions on molecular markers of Plasmodium falciparum drug resistance using parasites obtained from humans and mosquitoes at discrete time points. METHODS Dried blood spot samples collected in 2012 and 2017 community surveys in Asembo, Kenya were genotyped by Sanger sequencing for markers associated with resistance to SP (Pfdhfr, Pfdhps), CQ, AQ, lumefantrine (Pfcrt, Pfmdr1) and artemisinin (Pfk13). Temporal trends in the prevalence of these markers, including data from 2012 to 2017 as well as published data from 1996, 2001, 2007 from same area, were analysed. The same markers from mosquito oocysts collected in 2012 were compared with results from human blood samples. RESULTS The prevalence of SP dhfr/dhps quintuple mutant haplotype C50I51R59N108I164/S436G437E540A581A613 increased from 19.7% in 1996 to 86.0% in 2012, while an increase in the sextuple mutant haplotype C50I51R59N108I164/H436G437E540A581A613 containing Pfdhps-436H was found from 10.5% in 2012 to 34.6% in 2017. Resistant Pfcrt-76 T declined from 94.6% in 2007 to 18.3% in 2012 and 0.9% in 2017. Mutant Pfmdr1-86Y decreased across years from 74.8% in 1996 to zero in 2017, mutant Pfmdr1-184F and wild Pfmdr1-D1246 increased from 17.9% to 58.9% in 2007 to 55.9% and 90.1% in 2017, respectively. Pfmdr1 haplotype N86F184S1034N1042D1246 increased from 11.0% in 2007 to 49.6% in 2017. No resistant mutations in Pfk13 were found. Prevalence of Pfdhps-436H was lower while prevalence of Pfcrt-76 T was higher in mosquitoes than in human blood samples. CONCLUSION This study showed an increased prevalence of dhfr/dhps resistant markers over 20 years with the emergence of Pfdhps-436H mutant a decade ago in Asembo. The reversal of Pfcrt from CQ-resistant to CQ-sensitive genotype occurred following 19 years of CQ withdrawal. No Pfk13 markers associated with artemisinin resistance were detected, but the increased haplotype of Pfmdr1 N86F184S1034N1042D1246 was observed. The differences in prevalence of Pfdhps-436H and Pfcrt-76 T SNPs between two hosts and the role of mosquitoes in the transmission of drug resistant parasites require further investigation.
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Abstract
Population genetic diversity of Plasmodium falciparum antigenic loci is high despite large bottlenecks in population size during the parasite life cycle. The prevalence of genetically distinct haplotypes at these loci, while well characterized in humans, has not been thoroughly compared between human and mosquito hosts. We assessed parasite haplotype prevalence, diversity, and evenness using human and mosquito P. falciparum infections collected from the same households during a 14-month longitudinal cohort study using amplicon deep sequencing of two antigenic gene fragments (ama1 and csp). To a prior set of infected humans (n = 1,175/2,813; 86.2% sequencing success) and mosquito abdomens (n = 199/1,448; 95.5% sequencing success), we added sequences from infected mosquito heads (n = 134/1,448; 98.5% sequencing success). The overall and sample-level parasite populations were more diverse in mosquitoes than in humans. Additionally, haplotype prevalences were more even in the P. falciparum human population than in the mosquito population, consistent with balancing selection occurring at these loci in humans. In contrast, we observed that infections in humans were more likely to harbor a dominant haplotype than infections in mosquitoes, potentially due to removal of unfit strains by the human immune system. Finally, within a given mosquito, there was little overlap in genetic composition of abdomen and head infections, suggesting that infections may be cleared from the abdomen during a mosquito’s lifespan. Taken together, our observations provide evidence for the mosquito vector acting as a reservoir of sequence diversity in malaria parasite populations.
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Nkemngo FN, Mugenzi LMJ, Tchouakui M, Nguiffo-Nguete D, Wondji MJ, Mbakam B, Tchoupo M, Ndo C, Wanji S, Wondji CS. Xeno-monitoring of molecular drivers of artemisinin and partner drug resistance in P. falciparum populations in malaria vectors across Cameroon. Gene 2022; 821:146339. [PMID: 35183684 PMCID: PMC8942117 DOI: 10.1016/j.gene.2022.146339] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 02/10/2022] [Accepted: 02/14/2022] [Indexed: 01/29/2023]
Abstract
High Plasmodium infection rate in the major Anopheles vectors across Cameroon. Emerging signal of the R575I polymorphism in the k13 propeller domain backbone. Dominance of the N86F184mdr1 variants in natural P. falciparum populations. Low k13 and mdr1 genetic diversity in P. falciparum-infected mosquitoes.
Background Monitoring of drug resistance in Plasmodium populations is crucial for malaria control. This has primarily been performed in humans and rarely in mosquitoes where parasites genetic recombination occurs. Here, we characterized the Plasmodium spp populations in wild Anopheles vectors by analyzing the genetic diversity of the P. falciparum kelch13 and mdr1 gene fragments implicated in artemisinin and partner drug resistance across Cameroon in three major malaria vectors. Methods Anopheles mosquitoes were collected across nine localities in Cameroon and dissected into the head/thorax (H/T) and abdomen (Abd) after species identification. A TaqMan assay was performed to detect Plasmodium infection. Fragments of the Kelch 13 and mdr1 genes were amplified in P. falciparum positive samples and directly sequenced to assess their drug resistance polymorphisms and genetic diversity profile. Results The study revealed a high Plasmodium infection rate in the major Anopheles vectors across Cameroon. Notably, An. funestus vector recorded the highest sporozoite (8.0%) and oocyst (14.4%) infection rates. A high P. falciparum sporozoite rate (80.08%) alongside epidemiological signatures of significant P. malariae (15.9%) circulation were recorded in these vectors. Low genetic diversity with six (A578S, R575I, G450R, L663L, G453D, N458D) and eight (H53H, V62L, V77E, N86Y, G102G, L132I, H143H, Y184F) point mutations were observed in the k13 and mdr1 backbones respectively. Remarkably, the R575I (4.4%) k13 and Y184F (64.2%) mdr1 mutations were the predominant variants in the P. falciparum populations. Conclusion The emerging signal of the R575I polymorphism in the Pfk13 propeller backbone entails the regular surveillance of molecular markers to inform evidence-based policy decisions. Moreover, the high frequency of the 86N184F allele highlights concerns on the plausible decline in efficacy of artemisinin-combination therapies (ACTs); further implying that parasite genotyping from mosquitoes can provide a more relevant scale for quantifying resistance epidemiology in the field.
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Affiliation(s)
- Francis N Nkemngo
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon; Department of Microbiology and Parasitology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon.
| | - Leon M J Mugenzi
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon.
| | - Magellan Tchouakui
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon.
| | - Daniel Nguiffo-Nguete
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon.
| | - Murielle J Wondji
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon; Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom.
| | - Bertrand Mbakam
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon.
| | - Micareme Tchoupo
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon.
| | - Cyrille Ndo
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon; Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon.
| | - Samuel Wanji
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon; Research Foundation in Tropical Diseases and Environment, Buea, Cameroon.
| | - Charles S Wondji
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon; Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom.
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The Rare, the Best: Spread of Antimalarial-Resistant Plasmodium falciparum Parasites by Anopheles Mosquito Vectors. Microbiol Spectr 2021; 9:e0085221. [PMID: 34668767 PMCID: PMC8528099 DOI: 10.1128/spectrum.00852-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The emergence of resistance to antimalarials has prompted the steady switch to novel therapies for decades. Withdrawal of antimalarials, such as chloroquine in sub-Saharan Africa in the late 1990s, led to rapid declines in the prevalence of resistance markers after a few years, raising the possibility of reintroducing them for malaria treatment. Here, we provide evidence that the mosquito vector plays a crucial role in maintaining parasite genetic diversity. We followed the transmission dynamics of Plasmodium falciparum parasites through its vector in natural infections from gametocytes contained in the blood of asymptomatic volunteers until sporozoites subsequently developed in the mosquito salivary glands. We did not find any selection of the mutant or wild-type pfcrt 76 allele during development in the Anopheles mosquito vector. However, microsatellite genotyping indicated that minority genotypes were favored during transmission through the mosquito. The analysis of changes in the proportions of mutant and wild-type pfcrt 76 alleles showed that, regardless of the genotype, the less-represented allele in the gametocyte population was more abundant in mosquito salivary glands, indicating a selective advantage of the minority allele in the vector. Selection of minority genotypes in the vector would explain the persistence of drug-resistant alleles in the absence of drug pressure in areas with high malaria endemicity and high genetic diversity. Our results may have important epidemiological implications, as they predict the rapid re-emergence and spread of resistant genotypes if antimalarials that had previously selected resistant parasites are reintroduced for malaria prevention or treatment. IMPORTANCE Drug selection pressure in malaria patients is the cause of the emergence of resistant parasites. Resistance imposes a fitness cost for parasites in untreated infections, so withdrawal of the drug leads to the return of susceptible parasites. Little is known about the role of the malaria vector in this phenomenon. In an experimental study conducted in Cameroon, an area of high malaria transmission, we showed that the vector did not favor the parasites based on sensitivity or resistance criteria, but it did favor the selection of minority clones. This finding shows that the vector increases the diversity of plasmodial populations and could play an important role in falciparum malaria epidemiology by maintaining resistant clones despite the absence of therapeutic pressure.
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Mharakurwa S, Matsena-Zingoni Z, Mudare N, Matimba C, Gara TX, Makuwaza A, Maponga G, Munyati S, Gwanzura L, Mutambu SL, Mason P, Kobayashi T, Midzi N, Moss WJ, Ippolito MM. Steep Rebound of Chloroquine-Sensitive Plasmodium falciparum in Zimbabwe. J Infect Dis 2021; 223:306-309. [PMID: 32594154 DOI: 10.1093/infdis/jiaa368] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Accepted: 06/19/2020] [Indexed: 11/13/2022] Open
Abstract
Removal of chloroquine from national malaria formularies can lead to the reversion of resistant Plasmodium falciparum to wild-type. We report a steep decline in chloroquine-resistant P falciparum within 10 years of national discontinuation of chloroquine monotherapy in Zimbabwe. Drug resistance surveillance is a vital component of malaria control programs, and the experience with chloroquine in Zimbabwe and elsewhere in sub-Saharan Africa is illustrative of the potentially rapid and dramatic impact of drug policy on antimalarial resistance.
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Affiliation(s)
| | | | - Nobert Mudare
- Department of Health Sciences, Africa University, Mutare, Zimbabwe
| | | | | | - Aramu Makuwaza
- National Institute of Health Research Malaria Section, Harare, Zimbabwe
| | - Gladys Maponga
- National Institute of Health Research Malaria Section, Harare, Zimbabwe
| | - Shungu Munyati
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Lovemore Gwanzura
- Biomedical Research and Training Institute, Harare, Zimbabwe.,College of Health Sciences, University of Zimbabwe, Harare, Zimbabwe
| | - Susan L Mutambu
- Department of Health Sciences, Africa University, Mutare, Zimbabwe
| | - Peter Mason
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.,Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Nicholas Midzi
- National Institute of Health Research Malaria Section, Harare, Zimbabwe
| | - William J Moss
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.,Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Matthew M Ippolito
- Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.,Division of Clinical Pharmacology and Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Neff E, Evans CC, Jimenez Castro PD, Kaplan RM, Dharmarajan G. Drug Resistance in Filarial Parasites Does Not Affect Mosquito Vectorial Capacity. Pathogens 2020; 10:2. [PMID: 33375024 PMCID: PMC7822010 DOI: 10.3390/pathogens10010002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 12/15/2020] [Accepted: 12/18/2020] [Indexed: 12/19/2022] Open
Abstract
Parasite drug resistance presents a major obstacle to controlling and eliminating vector-borne diseases affecting humans and animals. While vector-borne disease dynamics are affected by factors related to parasite, vertebrate host and vector, research on drug resistance in filarial parasites has primarily focused on the parasite and vertebrate host, rather than the mosquito. However, we expect that the physiological costs associated with drug resistance would reduce the fitness of drug-resistant vs. drug-susceptible parasites in the mosquito wherein parasites are not exposed to drugs. Here we test this hypothesis using four isolates of the dog heartworm (Dirofilaria immitis)-two drug susceptible and two drug resistant-and two vectors-the yellow fever mosquito (Aedes aegypti) and the Asian tiger mosquito (Ae. albopictus)-as our model system. Our data indicated that while vector species had a significant effect on vectorial capacity, there was no significant difference in the vectorial capacity of mosquitoes infected with drug-resistant vs. drug-susceptible parasites. Consequently, contrary to expectations, our data indicate that drug resistance in D. immitis does not appear to reduce the transmission efficiency of these parasites, and thus the spread of drug-resistant parasites in the vertebrate population is unlikely to be mitigated by reduced fitness in the mosquito vector.
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Affiliation(s)
- Erik Neff
- Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, SC 29802, USA
| | - Christopher C. Evans
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA; (C.C.E.); (P.D.J.C.); (R.M.K.)
| | - Pablo D. Jimenez Castro
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA; (C.C.E.); (P.D.J.C.); (R.M.K.)
- Grupo de Parasitología Veterinaria, Universidad Nacional de Colombia, Bogotá 11001000, Colombia
| | - Ray M. Kaplan
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA; (C.C.E.); (P.D.J.C.); (R.M.K.)
| | - Guha Dharmarajan
- Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, SC 29802, USA
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Moser KA, Madebe RA, Aydemir O, Chiduo MG, Mandara CI, Rumisha SF, Chaky F, Denton M, Marsh PW, Verity R, Watson OJ, Ngasala B, Mkude S, Molteni F, Njau R, Warsame M, Mandike R, Kabanywanyi AM, Mahende MK, Kamugisha E, Ahmed M, Kavishe RA, Greer G, Kitojo CA, Reaves EJ, Mlunde L, Bishanga D, Mohamed A, Juliano JJ, Ishengoma DS, Bailey JA. Describing the current status of Plasmodium falciparum population structure and drug resistance within mainland Tanzania using molecular inversion probes. Mol Ecol 2020; 30:100-113. [PMID: 33107096 DOI: 10.1111/mec.15706] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/25/2020] [Accepted: 10/13/2020] [Indexed: 02/05/2023]
Abstract
High-throughput Plasmodium genomic data is increasingly useful in assessing prevalence of clinically important mutations and malaria transmission patterns. Understanding parasite diversity is important for identification of specific human or parasite populations that can be targeted by control programmes, and to monitor the spread of mutations associated with drug resistance. An up-to-date understanding of regional parasite population dynamics is also critical to monitor the impact of control efforts. However, this data is largely absent from high-burden nations in Africa, and to date, no such analysis has been conducted for malaria parasites in Tanzania countrywide. To this end, over 1,000 P. falciparum clinical isolates were collected in 2017 from 13 sites in seven administrative regions across Tanzania, and parasites were genotyped at 1,800 variable positions genome-wide using molecular inversion probes. Population structure was detectable among Tanzanian P. falciparum parasites, approximately separating parasites from the northern and southern districts and identifying genetically admixed populations in the north. Isolates from nearby districts were more likely to be genetically related compared to parasites sampled from more distant districts. Known drug resistance mutations were seen at increased frequency in northern districts (including two infections carrying pfk13-R561H), and additional variants with undetermined significance for antimalarial resistance also varied by geography. Malaria Indicator Survey (2017) data corresponded with genetic findings, including average region-level complexity-of-infection and malaria prevalence estimates. The parasite populations identified here provide important information on extant spatial patterns of genetic diversity of Tanzanian parasites, to which future surveys of genetic relatedness can be compared.
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Affiliation(s)
- Kara A Moser
- Institute for Global Health and Infectious Diseases, University of North Carolina Chapel Hill, Chapel Hill, NC, USA
| | | | - Ozkan Aydemir
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, USA
| | - Mercy G Chiduo
- National Institute for Medical Research, Tanga, Tanzania
| | - Celine I Mandara
- National Institute for Medical Research, Tanga, Tanzania.,Kilimanjaro Christian Medical Centre/Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Susan F Rumisha
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Frank Chaky
- National Malaria Control Program (NMCP), Dodoma, Tanzania
| | - Madeline Denton
- Institute for Global Health and Infectious Diseases, University of North Carolina Chapel Hill, Chapel Hill, NC, USA
| | - Patrick W Marsh
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, USA
| | - Robert Verity
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Oliver J Watson
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, USA.,MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Billy Ngasala
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Sigsbert Mkude
- National Malaria Control Program (NMCP), Dodoma, Tanzania
| | | | - Ritha Njau
- World Health Organization Country Office, Dar es Salaam, Tanzania
| | - Marian Warsame
- Gothenburg University, Gothenburg, Sweden.,Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | - Renata Mandike
- National Malaria Control Program (NMCP), Dodoma, Tanzania
| | | | | | - Erasmus Kamugisha
- Catholic University of Health and Allied Sciences/Bugando Medical Centre, Mwanza, Tanzania
| | - Maimuna Ahmed
- Catholic University of Health and Allied Sciences/Bugando Medical Centre, Mwanza, Tanzania
| | - Reginald A Kavishe
- Kilimanjaro Christian Medical Centre/Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - George Greer
- U.S. President's Malaria Initiative, U.S. Agency for International Development, U.S. Embassy, Dar es Salaam, Tanzania
| | - Chonge A Kitojo
- U.S. President's Malaria Initiative, U.S. Agency for International Development, U.S. Embassy, Dar es Salaam, Tanzania
| | - Erik J Reaves
- U.S. President's Malaria Initiative, U.S. Agency for International Development, U.S. Embassy, Dar es Salaam, Tanzania
| | - Linda Mlunde
- Jhpiego/Boresha Afya Project, Dar es Salaam, Tanzania
| | | | - Ally Mohamed
- National Malaria Control Program (NMCP), Dodoma, Tanzania
| | - Jonathan J Juliano
- Institute for Global Health and Infectious Diseases, University of North Carolina Chapel Hill, Chapel Hill, NC, USA.,Curriculum in Genetics and Molecular Biology, University of North Carolina Chapel Hill, Chapel Hill, NC, USA.,Department of Epidemiology, Gillings School of Global Public Health, Chapel Hill, NC, USA
| | - Deus S Ishengoma
- National Institute for Medical Research, Dar es Salaam, Tanzania.,Faculty of Pharmaceutical Sciences, Monash University, Melbourne, Vic, Australia.,Harvard T.H. Chan School of Public health, Harvard University, Boston, MA, USA
| | - Jeffrey A Bailey
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, USA
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10
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Balasubramanian S, Rahman RS, Lon C, Parobek C, Ubalee R, Hathaway N, Kuntawunginn W, My M, Vy D, Saxe J, Lanteri C, Lin FC, Spring M, Meshnick SR, Juliano JJ, Saunders DL, Lin JT. Efficient Transmission of Mixed Plasmodium falciparum/vivax Infections From Humans to Mosquitoes. J Infect Dis 2020; 221:428-437. [PMID: 31549156 PMCID: PMC7184918 DOI: 10.1093/infdis/jiz388] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 07/23/2019] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND In Southeast Asia, people are often coinfected with different species of malaria (Plasmodium falciparum [Pf] and Plasmodium vivax [Pv]) as well as with multiple clones of the same species. Whether particular species or clones within mixed infections are more readily transmitted to mosquitoes remains unknown. METHODS Laboratory-reared Anopheles dirus were fed on blood from 119 Pf-infected Cambodian adults, with 5950 dissected to evaluate for transmitted infection. Among 12 persons who infected mosquitoes, polymerase chain reaction and amplicon deep sequencing were used to track species and clone-specific transmission to mosquitoes. RESULTS Seven of 12 persons that infected mosquitoes harbored mixed Pf/Pv infection. Among these 7 persons, all transmitted Pv with 2 transmitting both Pf and Pv, leading to Pf/Pv coinfection in 21% of infected mosquitoes. Up to 4 clones of each species were detected within persons. Shifts in clone frequency were detected during transmission. However, in general, all parasite clones in humans were transmitted to mosquitoes, with individual mosquitoes frequently carrying multiple transmitted clones. CONCLUSIONS Malaria diversity in human hosts was maintained in the parasite populations recovered from mosquitoes fed on their blood. However, in persons with mixed Pf/Pv malaria, Pv appears to be transmitted more readily, in association with more prevalent patent gametocytemia.
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Affiliation(s)
- Sujata Balasubramanian
- Institute of Global Health and Infectious Diseases, University of North Carolina, Chapel Hill
| | - Rifat S Rahman
- Institute of Global Health and Infectious Diseases, University of North Carolina, Chapel Hill
| | - Chanthap Lon
- Armed Forces Research Institute of Medical Sciences, Phnom Penh, Cambodia
| | - Christian Parobek
- Institute of Global Health and Infectious Diseases, University of North Carolina, Chapel Hill
| | - Ratawan Ubalee
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Nicholas Hathaway
- Department of Bioinformatics and Integrated Biology, University of Massachusetts, Worcester
| | - Worachet Kuntawunginn
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Mok My
- Royal Cambodian Armed Forces, Phnom Penh, Cambodia
| | - Dav Vy
- Royal Cambodian Armed Forces, Phnom Penh, Cambodia
| | - Jeremy Saxe
- Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina, Chapel Hill
| | - Charlotte Lanteri
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Feng-Chang Lin
- Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina, Chapel Hill
| | - Michele Spring
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Steven R Meshnick
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill
| | - Jonathan J Juliano
- Institute of Global Health and Infectious Diseases, University of North Carolina, Chapel Hill
| | - David L Saunders
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
- US Army Medical Materiel Development Activity, Fort Detrick, Maryland
| | - Jessica T Lin
- Institute of Global Health and Infectious Diseases, University of North Carolina, Chapel Hill
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11
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Sekihara M, Tachibana SI, Yamauchi M, Yatsushiro S, Tiwara S, Fukuda N, Ikeda M, Mori T, Hirai M, Hombhanje F, Mita T. Lack of significant recovery of chloroquine sensitivity in Plasmodium falciparum parasites following discontinuance of chloroquine use in Papua New Guinea. Malar J 2018; 17:434. [PMID: 30477515 PMCID: PMC6260888 DOI: 10.1186/s12936-018-2585-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Accepted: 11/21/2018] [Indexed: 11/20/2022] Open
Abstract
Background Chloroquine treatment for Plasmodium falciparum has been discontinued in almost all endemic regions due to the spread of resistant isolates. Reversal of chloroquine susceptibility after chloroquine discontinuation has been reported in dozens of endemic regions. However, this phenomenon has been mostly observed in Africa and is not well documented in other malaria endemic regions. To investigate this, an ex vivo study on susceptibility to chloroquine and lumefantrine was conducted during 2016–2018 in Wewak, Papua New Guinea where chloroquine had been removed from the official malaria treatment regimen in 2010. Genotyping of pfcrt and pfmdr1 was also performed. Results In total, 368 patients were enrolled in this study. Average IC50 values for chloroquine were 106.6, 80.5, and 87.6 nM in 2016, 2017, and 2018, respectively. These values were not significantly changed from those obtained in 2002/2003 (108 nM). The majority of parasites harboured a pfcrt K76T the mutation responsible for chloroquine resistance. However, a significant upward trend was observed in the frequency of the K76 (wild) allele from 2.3% in 2016 to 11.7% in 2018 (P = 0.008; Cochran–Armitage trend test). Conclusions Eight years of chloroquine withdrawal has not induced a significant recovery of susceptibility in Papua New Guinea. However, an increasing tendency of parasites harbouring chloroquine-susceptible K76 suggests a possibility of resurgence of chloroquine susceptibility in the future. Electronic supplementary material The online version of this article (10.1186/s12936-018-2585-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Makoto Sekihara
- Department of Tropical Medicine and Parasitology, Juntendo University, Faculty of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Shin-Ichiro Tachibana
- Department of Tropical Medicine and Parasitology, Juntendo University, Faculty of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Masato Yamauchi
- Department of Tropical Medicine and Parasitology, Juntendo University, Faculty of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Shoki Yatsushiro
- Health Technology Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Takamatsu, Japan
| | - Steven Tiwara
- Wewak General Hospital, Wewak, East Sepik Province, Papua New Guinea
| | - Naoyuki Fukuda
- Department of Tropical Medicine and Parasitology, Juntendo University, Faculty of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Mie Ikeda
- Department of Tropical Medicine and Parasitology, Juntendo University, Faculty of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Toshiyuki Mori
- Department of Tropical Medicine and Parasitology, Juntendo University, Faculty of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Makoto Hirai
- Department of Tropical Medicine and Parasitology, Juntendo University, Faculty of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Francis Hombhanje
- Centre for Health Research & Diagnostics, Divine Word University, P.O. Box 483, Madang, Papua New Guinea
| | - Toshihiro Mita
- Department of Tropical Medicine and Parasitology, Juntendo University, Faculty of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
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12
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Grignard L, Gonçalves BP, Early AM, Daniels RF, Tiono AB, Guelbéogo WM, Ouédraogo A, van Veen EM, Lanke K, Diarra A, Nebie I, Sirima SB, Targett GA, Volkman SK, Neafsey DE, Wirth DF, Bousema T, Drakeley C. Transmission of molecularly undetectable circulating parasite clones leads to high infection complexity in mosquitoes post feeding. Int J Parasitol 2018; 48:671-677. [PMID: 29738740 PMCID: PMC6018601 DOI: 10.1016/j.ijpara.2018.02.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 01/04/2018] [Accepted: 02/26/2018] [Indexed: 11/24/2022]
Abstract
Additional parasite alleles were consistently identified in mosquitoes compared with the human blood sample they had fed on. Assessments of Plasmodium falciparum complexity relying on single time-point collections miss transmissible clones. Low-density gametocyte – producing clones are capable of successfully establishing infections in mosquitoes.
Plasmodium falciparum malaria infections often comprise multiple distinct parasite clones. Few datasets have directly assessed infection complexity in humans and mosquitoes they infect. Examining parasites using molecular tools may provide insights into the selective transmissibility of isolates. Using capillary electrophoresis genotyping and next generation amplicon sequencing, we analysed complexity of parasite infections in human blood and in the midguts of mosquitoes that became infected in membrane feeding experiments using the same blood material in two West African settings. Median numbers of clones in humans and mosquitoes were higher in samples from Burkina Faso (4.5, interquartile range 2–8 for humans; and 2, interquartile range 1–3 for mosquitoes) than in The Gambia (2, interquartile range 1–3 and 1, interquartile range 1–3, for humans and mosquitoes, respectively). Whilst the median number of clones was commonly higher in human blood samples, not all transmitted alleles were detectable in the human peripheral blood. In both study sample sets, additional parasite alleles were identified in mosquitoes compared with the matched human samples (10–88.9% of all clones/feeding assay, n = 73 feeding assays). The results are likely due to preferential amplification of the most abundant clones in peripheral blood but confirm the presence of low density clones that produce transmissible sexual stage parasites.
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Affiliation(s)
- Lynn Grignard
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK.
| | - Bronner P Gonçalves
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK
| | | | - Rachel F Daniels
- Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Alfred B Tiono
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Wamdaogo M Guelbéogo
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Alphonse Ouédraogo
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Elke M van Veen
- Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Kjerstin Lanke
- Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Amidou Diarra
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Issa Nebie
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Sodiomon B Sirima
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Geoff A Targett
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK
| | - Sarah K Volkman
- Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA; School of Nursing and Health Sciences, Simmons College, Boston, MA, USA
| | | | - Dyann F Wirth
- Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Teun Bousema
- Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK
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13
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Conrad MD, Mota D, Musiime A, Kilama M, Rek J, Kamya M, Dorsey G, Rosenthal PJ. Comparative Prevalence of Plasmodium falciparum Resistance-Associated Genetic Polymorphisms in Parasites Infecting Humans and Mosquitoes in Uganda. Am J Trop Med Hyg 2017; 97:1576-1580. [PMID: 29016309 PMCID: PMC5817777 DOI: 10.4269/ajtmh.17-0351] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Controlling malaria in high transmission areas, such as much of sub-Saharan Africa, will require concerted efforts to slow the spread of drug resistance and to impede malaria transmission. Understanding the fitness costs associated with the development of drug resistance, particularly within the context of transmission, can help guide policy decisions to accomplish these goals, as fitness constraints might lead to decreased transmission of drug-resistant strains. To determine if Plasmodium falciparum resistance-mediating polymorphisms impact on development at different parasite stages, we compared the genotypes of parasites infecting humans and mosquitoes from households in Uganda. Genotypes at 14 polymorphic loci in genes encoding putative transporters (pfcrt and pfmdr1) and folate pathway enzymes (pfdhfr and pfdhps) were characterized using ligase detection reaction-fluorescent microsphere assays. In paired analysis using the Wilcoxon signed-rank test, prevalences of mutations at 12 loci did not differ significantly between parasites infecting humans and mosquitoes. However, compared with parasites infecting humans, those infecting mosquitoes were enriched for the pfmdr1 86Y mutant allele (P = 0.0001) and those infecting Anopheles gambiae s.s. were enriched for the pfmdr1 86Y (P = 0.0001) and pfcrt 76T (P = 0.0412) mutant alleles. Our results suggest modest directional selection resulting from varied fitness costs during the P. falciparum life cycle. Better appreciation of the fitness implications of drug resistance mediating mutations can inform optimal malaria treatment and prevention strategies.
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Affiliation(s)
- Melissa D. Conrad
- Department of Medicine, University of California, San Francisco, California
| | - Daniel Mota
- Department of Medicine, University of California, San Francisco, California
| | - Alex Musiime
- Infectious Disease Research Collaboration, Kampala, Uganda
| | - Maxwell Kilama
- Infectious Disease Research Collaboration, Kampala, Uganda
| | - John Rek
- Infectious Disease Research Collaboration, Kampala, Uganda
| | - Moses Kamya
- Infectious Disease Research Collaboration, Kampala, Uganda;,Makerere University College of Health Sciences, Kampala, Uganda
| | - Grant Dorsey
- Department of Medicine, University of California, San Francisco, California
| | - Philip J. Rosenthal
- Department of Medicine, University of California, San Francisco, California;,Address correspondence to Philip J. Rosenthal, Department of Medicine, University of California, Box 0811, San Francisco, CA 94946. E-mail:
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14
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Zhang J, Huang J, Zhu F, Zhang J. Differential gene expression in Anopheles stephensi following infection with drug-resistant Plasmodium yoelii. Parasit Vectors 2017; 10:401. [PMID: 28851458 PMCID: PMC5576267 DOI: 10.1186/s13071-017-2326-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 08/08/2017] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The transmission of drug-resistant parasites by the mosquito may be influenced by the altered biological fitness of drug-resistant parasites and different immune reactions or metabolic change in the mosquito. At this point, little is known about the variations in mosquito immunity and metabolism when mosquitoes are infected with drug-resistant parasites. To understand the differential gene expression in Anopheles following infection with drug-resistant Plasmodium, we conducted a genome-wide transcriptomic profiling analysis of Anopheles stephensi following feeding on mice with drug-resistant or drug-sensitive P. yoelii, observed changes in gene expression profiles and identified transcripts affected by the drug-resistant parasite. RESULTS To study the impact of drug-resistant Plasmodium infections on An. stephensi gene transcription, we analyzed the three major transition stages of Plasmodium infections: at 24 h and 13 and 19 days after blood-feeding. Six cDNA libraries (R-As24h, R-As13d, R-As19d,S-As24h, S-As13dand S-As19d) were constructed, and RNA sequencing was subsequently performed. In total, approximately 50.1 million raw reads, 47.9 million clean reads and 7.18G clean bases were obtained. Following differentially expressed gene (DEG) analysis, GO enrichment analysis of DEGs, and functional classification by KEGG, we showed that the variations in gene expression in An. stephensi infected by the drug-resistant P. yoelii NSM occurred mainly at 13 days after blood meal during sporozoite migration through the hemolymph. The differentially expressed genes included those functioning in some important immune reaction and iron metabolism pathways, such as pattern recognition receptors, regulators of the JNK pathway, components of the phagosome pathway, regulators of the melanization response, activators of complement reactions, insulin signaling cascade members, oxidative stress and detoxification proteins. CONCLUSIONS Our study shows that drug-resistant P. yoelii NSM has an impact on the transcript abundance levels of An.stephensi mostly at 13 days after blood meal during sporozoite migration through the hemolymph and that most differentially expressed genes were downregulated. Our results highlight the need for a better understanding of selective pressures from these differentially expressed genes of the drug-resistant Plasmodium in the mosquito and the different transmission patterns of drug-resistant Plasmodium by Anopheles.
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Affiliation(s)
- Jingru Zhang
- Department of Pathobiology, the Third Military Medical University, Chongqing, People's Republic of China
| | - Jiacheng Huang
- Students brigade 5, The Third Military Medical University, Chongqing, People's Republic of China
| | - Feng Zhu
- Department of Pathobiology, the Third Military Medical University, Chongqing, People's Republic of China
| | - Jian Zhang
- Department of Pathobiology, the Third Military Medical University, Chongqing, People's Republic of China.
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15
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Evolution of Fitness Cost-Neutral Mutant PfCRT Conferring P. falciparum 4-Aminoquinoline Drug Resistance Is Accompanied by Altered Parasite Metabolism and Digestive Vacuole Physiology. PLoS Pathog 2016; 12:e1005976. [PMID: 27832198 PMCID: PMC5104409 DOI: 10.1371/journal.ppat.1005976] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 10/03/2016] [Indexed: 11/19/2022] Open
Abstract
Southeast Asia is an epicenter of multidrug-resistant Plasmodium falciparum strains. Selective pressures on the subcontinent have recurrently produced several allelic variants of parasite drug resistance genes, including the P. falciparum chloroquine resistance transporter (pfcrt). Despite significant reductions in the deployment of the 4-aminoquinoline drug chloroquine (CQ), which selected for the mutant pfcrt alleles that halted CQ efficacy decades ago, the parasite pfcrt locus is continuously evolving. This is highlighted by the presence of a highly mutated allele, Cam734 pfcrt, which has acquired the singular ability to confer parasite CQ resistance without an associated fitness cost. Here, we used pfcrt-specific zinc-finger nucleases to genetically dissect this allele in the pathogenic setting of asexual blood-stage infection. Comparative analysis of drug resistance and growth profiles of recombinant parasites that express Cam734 or variants thereof, Dd2 (the most common Southeast Asian variant), or wild-type pfcrt, revealed previously unknown roles for PfCRT mutations in modulating parasite susceptibility to multiple antimalarial agents. These results were generated in the GC03 strain, used in multiple earlier pfcrt studies, and might differ in natural isolates harboring this allele. Results presented herein show that Cam734-mediated CQ resistance is dependent on the rare A144F mutation that has not been observed beyond Southeast Asia, and reveal distinct impacts of this and other Cam734-specific mutations on CQ resistance and parasite growth rates. Biochemical assays revealed a broad impact of mutant PfCRT isoforms on parasite metabolism, including nucleoside triphosphate levels, hemoglobin catabolism and disposition of heme, as well as digestive vacuole volume and pH. Results from our study provide new insights into the complex molecular basis and physiological impact of PfCRT-mediated antimalarial drug resistance, and inform ongoing efforts to characterize novel pfcrt alleles that can undermine the efficacy of first-line antimalarial drug regimens. Point mutations in the Plasmodium falciparum chloroquine resistance transporter (PfCRT) earlier thwarted the clinical efficacy of chloroquine, the former gold standard, and constitute a major determinant of parasite susceptibility to antimalarial drugs. Recently, we reported that the highly mutated Cambodian PfCRT isoform Cam734 is fitness-neutral in terms of parasite growth, unlike other less fit isoforms such as Dd2 that are outcompeted by wild-type parasites in the absence of CQ pressure. Using pfcrt-specific zinc-finger nucleases to genetically dissect the Cam734 allele, we report that its unique constituent mutations directly contribute to CQ resistance and collectively offset fitness costs associated with intermediate mutational steps. We also report that these mutations can contribute to resistance or increased sensitivity to multiple first-line partner drugs. Using isogenic parasite lines, we provide evidence of changes in parasite metabolism associated with the Cam734 allele compared to Dd2. We also observe a close correlation between CQ inhibition of hemozoin formation and parasite growth, and provide evidence that Cam734 PfCRT can modulate drug potency depending on its membrane electrochemical gradient. Our data highlight the capacity of PfCRT to evolve new states of antimalarial drug resistance and to offset associated fitness costs through its impact on parasite physiology and hemoglobin catabolism.
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16
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Gabryszewski SJ, Modchang C, Musset L, Chookajorn T, Fidock DA. Combinatorial Genetic Modeling of pfcrt-Mediated Drug Resistance Evolution in Plasmodium falciparum. Mol Biol Evol 2016; 33:1554-70. [PMID: 26908582 PMCID: PMC4868112 DOI: 10.1093/molbev/msw037] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The emergence of drug resistance continuously threatens global control of infectious diseases, including malaria caused by the protozoan parasite Plasmodium falciparum. A critical parasite determinant is the P. falciparum chloroquine resistance transporter (PfCRT), the primary mediator of chloroquine (CQ) resistance (CQR), and a pleiotropic modulator of susceptibility to several first-line artemisinin-based combination therapy partner drugs. Aside from the validated CQR molecular marker K76T, P. falciparum parasites have acquired at least three additional pfcrt mutations, whose contributions to resistance and fitness have been heretofore unclear. Focusing on the quadruple-mutant Ecuadorian PfCRT haplotype Ecu1110 (K76T/A220S/N326D/I356L), we genetically modified the pfcrt locus of isogenic, asexual blood stage P. falciparum parasites using zinc-finger nucleases, producing all possible combinations of intermediate pfcrt alleles. Our analysis included the related quintuple-mutant PfCRT haplotype 7G8 (Ecu1110 + C72S) that is widespread throughout South America and the Western Pacific. Drug susceptibilities and in vitro growth profiles of our combinatorial pfcrt-modified parasites were used to simulate the mutational trajectories accessible to parasites as they evolved CQR. Our results uncover unique contributions to parasite drug resistance and growth for mutations beyond K76T and predict critical roles for the CQ metabolite monodesethyl-CQ and the related quinoline-type drug amodiaquine in driving mutant pfcrt evolution. Modeling outputs further highlight the influence of parasite proliferation rates alongside gains in drug resistance in dictating successful trajectories. Our findings suggest that P. falciparum parasites have navigated constrained pfcrt adaptive landscapes by means of probabilistically rare mutational bursts that led to the infrequent emergence of pfcrt alleles in the field.
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Affiliation(s)
| | - Charin Modchang
- Department of Physics, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Lise Musset
- Laboratoire de Parasitologie, WHO Collaborating Center for Surveillance of Anti-Malarial Drug Resistance, Institut Pasteur de la Guyane, Cayenne, French Guiana
| | - Thanat Chookajorn
- Genomics and Evolutionary Medicine Unit, Center of Excellence in Malaria, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - David A Fidock
- Department of Microbiology and Immunology, Columbia University Medical Center, New York Division of Infectious Diseases, Department of Medicine, Columbia University Medical Center, New York, NY
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17
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Cui L, Mharakurwa S, Ndiaye D, Rathod PK, Rosenthal PJ. Antimalarial Drug Resistance: Literature Review and Activities and Findings of the ICEMR Network. Am J Trop Med Hyg 2015; 93:57-68. [PMID: 26259943 PMCID: PMC4574275 DOI: 10.4269/ajtmh.15-0007] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 04/27/2015] [Indexed: 11/07/2022] Open
Abstract
Antimalarial drugs are key tools for the control and elimination of malaria. Recent decreases in the global malaria burden are likely due, in part, to the deployment of artemisinin-based combination therapies. Therefore, the emergence and potential spread of artemisinin-resistant parasites in southeast Asia and changes in sensitivities to artemisinin partner drugs have raised concerns. In recognition of this urgent threat, the International Centers of Excellence for Malaria Research (ICEMRs) are closely monitoring antimalarial drug efficacy and studying the mechanisms underlying drug resistance. At multiple sentinel sites of the global ICEMR network, research activities include clinical studies to track the efficacies of antimalarial drugs, ex vivo/in vitro assays to measure drug susceptibilities of parasite isolates, and characterization of resistance-mediating parasite polymorphisms. Taken together, these efforts offer an increasingly comprehensive assessment of the efficacies of antimalarial therapies, and enable us to predict the emergence of drug resistance and to guide local antimalarial drug policies. Here we briefly review worldwide antimalarial drug resistance concerns, summarize research activities of the ICEMRs related to drug resistance, and assess the global impacts of the ICEMR programs.
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Affiliation(s)
- Liwang Cui
- *Address correspondence to Liwang Cui, Department of Entomology, Pennsylvania State University, 501 ASI Building, University Park, PA 16802, E-mail: or Philip J. Rosenthal, Department of Medicine, Box 0811, University of California, San Francisco, CA 94110. E-mail:
| | | | | | | | - Philip J. Rosenthal
- *Address correspondence to Liwang Cui, Department of Entomology, Pennsylvania State University, 501 ASI Building, University Park, PA 16802, E-mail: or Philip J. Rosenthal, Department of Medicine, Box 0811, University of California, San Francisco, CA 94110. E-mail:
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18
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Petersen I, Gabryszewski SJ, Johnston GL, Dhingra SK, Ecker A, Lewis RE, de Almeida MJ, Straimer J, Henrich PP, Palatulan E, Johnson DJ, Coburn-Flynn O, Sanchez C, Lehane AM, Lanzer M, Fidock DA. Balancing drug resistance and growth rates via compensatory mutations in the Plasmodium falciparum chloroquine resistance transporter. Mol Microbiol 2015; 97:381-95. [PMID: 25898991 DOI: 10.1111/mmi.13035] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2015] [Indexed: 11/28/2022]
Abstract
The widespread use of chloroquine to treat Plasmodium falciparum infections has resulted in the selection and dissemination of variant haplotypes of the primary resistance determinant PfCRT. These haplotypes have encountered drug pressure and within-host competition with wild-type drug-sensitive parasites. To examine these selective forces in vitro, we genetically engineered P. falciparum to express geographically diverse PfCRT haplotypes. Variant alleles from the Philippines (PH1 and PH2, which differ solely by the C72S mutation) both conferred a moderate gain of chloroquine resistance and a reduction in growth rates in vitro. Of the two, PH2 showed higher IC50 values, contrasting with reduced growth. Furthermore, a highly mutated pfcrt allele from Cambodia (Cam734) conferred moderate chloroquine resistance and enhanced growth rates, when tested against wild-type pfcrt in co-culture competition assays. These three alleles mediated cross-resistance to amodiaquine, an antimalarial drug widely used in Africa. Each allele, along with the globally prevalent Dd2 and 7G8 alleles, rendered parasites more susceptible to lumefantrine, the partner drug used in the leading first-line artemisinin-based combination therapy. These data reveal ongoing region-specific evolution of PfCRT that impacts drug susceptibility and relative fitness in settings of mixed infections, and raise important considerations about optimal agents to treat chloroquine-resistant malaria.
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Affiliation(s)
- Ines Petersen
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.,Hygiene Institut, Abteilung Parasitologie, Universitätsklinikum Heidelberg, 69120, Heidelberg, Germany
| | - Stanislaw J Gabryszewski
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Geoffrey L Johnston
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.,School of International and Public Affairs, Columbia University, New York, NY, 10027, USA
| | - Satish K Dhingra
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.,Department of Biological Sciences, Binghamton University, Binghamton, NY, 13902, USA
| | - Andrea Ecker
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Rebecca E Lewis
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | | | - Judith Straimer
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Philipp P Henrich
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Eugene Palatulan
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - David J Johnson
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Olivia Coburn-Flynn
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Cecilia Sanchez
- Hygiene Institut, Abteilung Parasitologie, Universitätsklinikum Heidelberg, 69120, Heidelberg, Germany
| | - Adele M Lehane
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Michael Lanzer
- Hygiene Institut, Abteilung Parasitologie, Universitätsklinikum Heidelberg, 69120, Heidelberg, Germany
| | - David A Fidock
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.,Division of Infectious Diseases, Department of Medicine, Columbia University Medical Center, New York, NY, 10032, USA
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19
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Heinberg A, Kirkman L. The molecular basis of antifolate resistance in Plasmodium falciparum: looking beyond point mutations. Ann N Y Acad Sci 2015; 1342:10-8. [PMID: 25694157 DOI: 10.1111/nyas.12662] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Drugs that target the folate-synthesis pathway have a long history of effectiveness against a variety of pathogens. As antimalarials, the antifolates were safe and well tolerated, but resistance emerged quickly and has persisted even with decreased drug pressure. The primary determinants of resistance in Plasmodium falciparum are well-described point mutations in the enzymes dihydropteroate synthase and dihydrofolate reductase targeted by the combination sulfadoxine-pyrimethamine. Recent work has highlighted the contributions of additional parasite adaptation to antifolate resistance. In fact, the evolution of antifolate-resistant parasites is multifaceted and complex. Gene amplification of the first enzyme in the parasite folate synthesis pathway, GTP-cyclohydrolase, is strongly associated with resistant parasites and potentially contributes to persistence of resistant parasites. Further understanding of how parasites adjust flux through the folate pathway is important to the further development of alternative agents targeting this crucial synthesis pathway.
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