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Chaianantakul N, Sungkapong T, Nikhomkham K, Sanseewong K, Kornsang S. A Novel Nested Multiplex Polymerase Chain Reaction Assay for Malaria Diagnosis Using the Hydroxymethyl Dihydropterin Pyrophosphokinase-Dihydropteroate Synthase (hppk-dhps) Gene. Am J Trop Med Hyg 2023; 109:770-777. [PMID: 37696509 PMCID: PMC10551067 DOI: 10.4269/ajtmh.23-0130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 07/21/2023] [Indexed: 09/13/2023] Open
Abstract
There are many techniques for malaria diagnosis. Currently, the nested polymerase chain reaction (PCR) method based on a small subunit ribosomal RNA gene (18S rRNA) has been used as a confirmatory method. However, this method is time-consuming, laborious, and costly. Therefore, the objective of this study was to develop nested multiplex PCR for Plasmodium species identification using the dihydropterin pyrophosphokinase-dihydropteroate synthase (hppk-dhps) gene. Genus- and species-specific primers for the hppk-dhps gene were designed. The performance of the novel nested multiplex PCR was compared with 18S rRNA nested PCR. A total of 115 blood samples were used in this study, including 84 infected samples and 31 uninfected samples. Analysis of the blood samples by nested multiplex PCR targeting the hppk-dhps gene identified 81 infected cases. The level of agreement between this novel method and 18S rRNA nested PCR was 97.4%. Further, the novel method successfully detected all human malaria parasites except Plasmodium ovale and detected mixed Plasmodium falciparum/Plasmodium vivax infections. The sensitivity and specificity obtained from this novel method were 96.4% and 100%, respectively. The limit of detection of the hppk-dhps nested multiplex PCR for P. falciparum and P. vivax was 500 parasites/µL and 4 parasites/µL, respectively. The lowest parasite gDNA detected by this method was 0.5 ng/µL for P. falciparum and 0.1 ng/µL for P. vivax. These results corroborate that the hppk-dhps gene is a novel amplification target for the detection of human malaria. This novel target PCR-based method is a beneficial approach for malaria diagnosis, as well as species identification and differentiation.
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Affiliation(s)
- Natpasit Chaianantakul
- Department of Medical Technology, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok, Thailand
| | - Tippawan Sungkapong
- Department of Medical Technology, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok, Thailand
| | - Kanokwan Nikhomkham
- Department of Medical Technology, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok, Thailand
| | - Kansuda Sanseewong
- Department of Medical Technology, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok, Thailand
| | - Sawanya Kornsang
- Department of Medical Technology, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok, Thailand
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2
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Leutenegger CM, Lozoya CE, Tereski J, Andrews J, Mitchell KD, Meeks C, Willcox JL, Freeman G, Richmond HL, Savard C, Evason MD. Comparative study of a broad qPCR panel and centrifugal flotation for detection of gastrointestinal parasites in fecal samples from dogs and cats in the United States. Parasit Vectors 2023; 16:288. [PMID: 37587483 PMCID: PMC10433665 DOI: 10.1186/s13071-023-05904-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 07/27/2023] [Indexed: 08/18/2023] Open
Abstract
BACKGROUND For decades, zinc sulfate centrifugal fecal flotation microscopy (ZCF) has been the mainstay technique for gastrointestinal (GI) parasite screening at veterinary clinics and laboratories. Elsewhere, PCR has replaced microscopy because of generally increased sensitivity and detection capabilities; however, until recently it has been unavailable commercially. Therefore, the primary aim of this study was to compare the performance of real-time PCR (qPCR) and ZCF for fecal parasite screening. Secondary aims included further characterization of markers for hookworm treatment resistance and Giardia spp. assemblages with zoonotic potential and qPCR optimization. METHODS A convenience sampling of 931 canine/feline fecal samples submitted to a veterinary reference laboratory for routine ZCF from the Northeast US (11/2022) was subsequently evaluated by a broad qPCR panel following retention release. Detection frequency and agreement (kappa statistics) were evaluated between ZCF and qPCR for seven GI parasites [hookworm/(Ancylostoma spp.), roundworm/(Toxocara spp.), whipworm/(Trichuris spp.), Giardia duodenalis, Cystoisospora spp., Toxoplasma gondii, and Tritrichomonas blagburni] and detections per sample. Total detection frequencies were compared using a paired t-test; positive sample and co-infection frequencies were compared using Pearson's chi-squared test (p ≤ 0.05 significant) and qPCR frequency for hookworm benzimidazole (BZ) resistance (F167Y) and zoonotic Giardia spp. assemblage markers calculated. Confirmatory testing, characterization, and qPCR optimization were carried out with Sanger sequencing. RESULTS qPCR detected a significantly higher overall parasite frequency (n = 679) compared to ZCF (n = 437) [p = < 0.0001, t = 14.38, degrees-of-freedom (df) = 930] and 2.6 × the co-infections [qPCR (n = 172) vs. ZCF (n = 66)], which was also significant (p = < 0.0001, X2 = 279.49; df = 1). While overall agreement of parasite detection was substantial [kappa = 0.74; (0.69-0.78], ZCF-undetected parasites reduced agreement for individual and co-infected samples. qPCR detected markers for Ancylostoma caninum BZ resistance (n = 5, 16.1%) and Giardia with zoonotic potential (n = 22, 9.1%) as well as two parasites undetected by ZCF (T. gondii/T. blagburni). Sanger sequencing detected novel roundworm species, and qPCR optimization provided detection beyond ZCF. CONCLUSIONS These results demonstrate the statistically significant detection frequency advantage offered by qPCR compared to routine ZCF for both single and co-infections. While overall agreement was excellent, this rapid, commercially available qPCR panel offers benefits beyond ZCF with detection of markers for Giardia assemblages with zoonotic potential and hookworm (A. caninum) BZ resistance.
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Affiliation(s)
| | | | | | - Jan Andrews
- Antech Diagnostics, Inc, Fountain Valley, CA, USA
| | | | - Cathy Meeks
- Antech Diagnostics, Inc, Fountain Valley, CA, USA
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3
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Chavtur C, Staubus WJ, Ho M, Hergott DEB, Seilie AM, Healy S, Duffy P, Jackson L, Talley A, Kappe SHI, Hoffman SL, Richie TL, Kublin JG, Chang M, Murphy SC. Plasmodium 18S Ribosomal RNA Biomarker Clearance After Food and Drug Administration-Approved Antimalarial Treatment in Controlled Human Malaria Infection Trials. Open Forum Infect Dis 2023; 10:ofad202. [PMID: 37265668 PMCID: PMC10230565 DOI: 10.1093/ofid/ofad202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 04/12/2023] [Indexed: 06/03/2023] Open
Abstract
Background Sensitive molecular assays, such as quantitative reverse-transcription polymerase chain reaction (qRT-PCR) of Plasmodium 18S ribosomal RNA (rRNA), are increasingly the primary method of detecting infections in controlled human malaria infection (CHMI) trials. However, thick blood smears (TBSs) remain the main method for confirming clearance of parasites after curative treatment, in part owing to uncertainty regarding biomarker clearance rates. Methods For this analysis, 18S rRNA qRT-PCR data were compiled from 127 Plasmodium falciparum-infected participants treated with chloroquine or atovaquone-proguanil in 6 CHMI studies conducted in Seattle, Washington, over the past decade. A survival analysis approach was used to compare biomarker and TBS clearance times among studies. The effect of the parasite density at which treatment was initiated on clearance time was estimated using linear regression. Results The median time to biomarker clearance was 3 days (interquartile range, 3-5 days), while the median time to TBS clearance was 1 day (1-2 days). Time to biomarker clearance increased with the parasite density at which treatment was initiated. Parasite density did not have a significant effect on TBS clearance. Conclusions The Plasmodium 18S rRNA biomarker clears quickly and can be relied on to confirm the adequacy of Food and Drug Administration-approved treatments in CHMI studies at nonendemic sites.
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Affiliation(s)
- Chris Chavtur
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Weston J Staubus
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Mabel Ho
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Dianna E B Hergott
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
- Department of Epidemiology, School of Public Health, University of Washington, Seattle, Washington, USA
| | - Annette M Seilie
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Sara Healy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
| | - Patrick Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
| | - Lisa Jackson
- Kaiser Permanente Washington Health Research Institute, Seattle, Washington, USA
| | | | - Stefan H I Kappe
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
- Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | | | | | - James G Kublin
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
- Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Ming Chang
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Sean C Murphy
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
- Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
- Department of Microbiology, University of Washington, Seattle, Washington, USA
- Department of Laboratories, Seattle Children's Hospital, Seattle, Washington, USA
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4
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Flannery EL, Kangwanrangsan N, Chuenchob V, Roobsoong W, Fishbaugher M, Zhou K, Billman ZP, Martinson T, Olsen TM, Schäfer C, Campo B, Murphy SC, Mikolajczak SA, Kappe SH, Sattabongkot J. Plasmodium vivax latent liver infection is characterized by persistent hypnozoites, hypnozoite-derived schizonts, and time-dependent efficacy of primaquine. Mol Ther Methods Clin Dev 2022; 26:427-440. [PMID: 36092359 PMCID: PMC9418049 DOI: 10.1016/j.omtm.2022.07.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 07/31/2022] [Indexed: 01/13/2023]
Abstract
Plasmodium vivax is a malaria-causing pathogen that establishes a dormant form in the liver (the hypnozoite), which can activate weeks, months, or years after the primary infection to cause a relapse, characterized by secondary blood-stage infection. These asymptomatic and undetectable latent liver infections present a significant obstacle to the goal of global malaria eradication. We use a human liver-chimeric mouse model (FRG huHep) to study P. vivax hypnozoite latency and activation in an in vivo model system. Functional activation of hypnozoites and formation of secondary schizonts is demonstrated by first eliminating primary liver schizonts using a schizont-specific antimalarial tool compound, and then measuring recurrence of secondary liver schizonts in the tissue and an increase in parasite RNA within the liver. We also reveal that, while primaquine does not immediately eliminate hypnozoites from the liver, it arrests developing schizonts and prevents activation of hypnozoites, consistent with its clinical activity in humans. Our findings demonstrate that the FRG huHep model can be used to study the biology of P. vivax infection and latency and assess the activity of anti-relapse drugs.
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Affiliation(s)
- Erika L. Flannery
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA 98109, USA
- Corresponding author Erika L. Flannery, Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA 98109, USA.
| | - Niwat Kangwanrangsan
- Department of Pathobiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Vorada Chuenchob
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA 98109, USA
| | - Wanlapa Roobsoong
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Matthew Fishbaugher
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA 98109, USA
| | - Kevin Zhou
- Department of Laboratory Medicine and Pathology, and Department of Microbiology, University of Washington, Seattle, WA 98115, USA
| | - Zachary P. Billman
- Department of Laboratory Medicine and Pathology, and Department of Microbiology, University of Washington, Seattle, WA 98115, USA
| | - Thomas Martinson
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA 98109, USA
| | - Tayla M. Olsen
- Department of Laboratory Medicine and Pathology, and Department of Microbiology, University of Washington, Seattle, WA 98115, USA
| | - Carola Schäfer
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA 98109, USA
| | - Brice Campo
- Medicines for Malaria Venture, Geneva, Switzerland
| | - Sean C. Murphy
- Department of Laboratory Medicine and Pathology, and Department of Microbiology, University of Washington, Seattle, WA 98115, USA
| | - Sebastian A. Mikolajczak
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA 98109, USA
| | - Stefan H.I. Kappe
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA 98109, USA
- Department of Pediatrics, University of Washington, Seattle, WA 98105, USA
- Corresponding author Stefan H.I. Kappe, Department of Pediatrics, University of Washington, Seattle, WA 98105, USA.
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Corresponding author Jetsumon Sattabongkot, Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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5
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Matsubara J, Chang M, Seilie AM, Murphy SC. Flow Cytometric Sorting of Infected Erythrocytes Demonstrates Reliable Detection of Individual Ring-Stage Plasmodium falciparum Parasites by Plasmodium 18S rRNA Reverse Transcription Polymerase Chain Reaction. Am J Trop Med Hyg 2022; 106:tpmd211226. [PMID: 35405648 PMCID: PMC9209910 DOI: 10.4269/ajtmh.21-1226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 01/17/2022] [Indexed: 11/12/2022] Open
Abstract
Molecular diagnostic tests for Plasmodium falciparum parasites are increasingly used to enable ultrasensitive detection of infection in clinical trials and field surveillance studies. Ribonucleic acid (RNA)-based assays targeting 18S rRNA are particularly sensitive with limits of detection reported to comprise a single infected red blood cell (RBC) in a relatively large volume of blood. However, the validation testing at such limiting concentrations is hampered by the so-called Poisson distribution of such rare events, which can lead laboratorians to inaccurately set the limit of detection higher (i.e., less sensitive) than the assay can actually detect. Here we set out to formally demonstrate the analytical sensitivity of the Plasmodium 18S rRNA quantitative reverse transcription PCR (qRT-PCR). Fluorescence-activated cell sorting (FACS) was used on synchronous P. falciparum cultures doubly stained for DNA and RNA and was followed by qRT-PCR on the individual sorted cells spiked with negative whole blood. Over 95% of individual single-ring infected RBCs were detected by qRT-PCR. The formally measured median 18S rRNA content per individual ring-stage P. falciparum parasite was 9,550 copies (interquartile range 8,130-12,300). Thus, one can confidently rely on Plasmodium 18S rRNA qRT-PCR to detect one parasite per 50-µL blood sample.
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Affiliation(s)
- Jokichi Matsubara
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington
- Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Ming Chang
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington
- Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Annette M Seilie
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington
- Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Sean C Murphy
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington
- Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
- Department of Microbiology, University of Washington, Seattle, Washington
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6
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Goswami D, Kumar S, Betz W, Armstrong JM, Haile MT, Camargo N, Parthiban C, Seilie AM, Murphy SC, Vaughan AM, Kappe SH. A Plasmodium falciparum ATP binding cassette transporter is essential for liver stage entry into schizogony. iScience 2022; 25:104224. [PMID: 35521513 PMCID: PMC9061783 DOI: 10.1016/j.isci.2022.104224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 03/01/2022] [Accepted: 04/06/2022] [Indexed: 11/27/2022] Open
Abstract
Plasmodium sporozoites invade hepatocytes and transform into liver stages within a parasitophorous vacuole (PV). The parasites then grow and replicate their genome to form exoerythrocytic merozoites that infect red blood cells. We report that the human malaria parasite Plasmodium falciparum (Pf) expresses a C-type ATP-binding cassette transporter, Pf ABCC2, which marks the transition from invasive sporozoite to intrahepatocytic early liver stage. Using a humanized mouse infection model, we show that Pf ABCC2 localizes to the parasite plasma membrane in early and mid-liver stage parasites but is not detectable in late liver stages. Pf abcc2— sporozoites invade hepatocytes, form a PV, and transform into liver stage trophozoites but cannot transition to exoerythrocytic schizogony and fail to transition to blood stage infection. Thus, Pf ABCC2 is an expression marker for early phases of parasite liver infection and plays an essential role in the successful initiation of liver stage replication. Pf ABCC2 expression marks the transition from sporozoite to early liver stage Pf ABCC2 localizes to the early and mid-liver stage plasma membrane Pf ABCC2 is critical for initiation of exoerythrocytic schizogony Pf abcc2– liver stages fail to transition to blood stage infection
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7
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Mpina M, Stabler TC, Schindler T, Raso J, Deal A, Acuche Pupu L, Nyakarungu E, Del Carmen Ovono Davis M, Urbano V, Mtoro A, Hamad A, Lopez MSA, Pasialo B, Eyang MAO, Rivas MR, Falla CC, García GA, Momo JC, Chuquiyauri R, Saverino E, Preston Church LW, Kim Lee Sim B, Manguire B, Tanner M, Maas C, Abdulla S, Billingsley PF, Hoffman SL, Jongo S, Richie TL, Daubenberger CA. Diagnostic performance and comparison of ultrasensitive and conventional rapid diagnostic test, thick blood smear and quantitative PCR for detection of low-density Plasmodium falciparum infections during a controlled human malaria infection study in Equatorial Guinea. Malar J 2022; 21:99. [PMID: 35331251 PMCID: PMC8943516 DOI: 10.1186/s12936-022-04103-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/23/2022] [Indexed: 12/02/2022] Open
Abstract
Background Progress towards malaria elimination has stagnated, partly because infections persisting at low parasite densities comprise a large reservoir contributing to ongoing malaria transmission and are difficult to detect. This study compared the performance of an ultrasensitive rapid diagnostic test (uRDT) designed to detect low density infections to a conventional RDT (cRDT), expert microscopy using Giemsa-stained thick blood smears (TBS), and quantitative polymerase chain reaction (qPCR) during a controlled human malaria infection (CHMI) study conducted in malaria exposed adults (NCT03590340). Methods Blood samples were collected from healthy Equatoguineans aged 18–35 years beginning on day 8 after CHMI with 3.2 × 103 cryopreserved, infectious Plasmodium falciparum sporozoites (PfSPZ Challenge, strain NF54) administered by direct venous inoculation. qPCR (18s ribosomal DNA), uRDT (Alere™ Malaria Ag P.f.), cRDT [Carestart Malaria Pf/PAN (PfHRP2/pLDH)], and TBS were performed daily until the volunteer became TBS positive and treatment was administered. qPCR was the reference for the presence of Plasmodium falciparum parasites. Results 279 samples were collected from 24 participants; 123 were positive by qPCR. TBS detected 24/123 (19.5% sensitivity [95% CI 13.1–27.8%]), uRDT 21/123 (17.1% sensitivity [95% CI 11.1–25.1%]), cRDT 10/123 (8.1% sensitivity [95% CI 4.2–14.8%]); all were 100% specific and did not detect any positive samples not detected by qPCR. TBS and uRDT were more sensitive than cRDT (TBS vs. cRDT p = 0.015; uRDT vs. cRDT p = 0.053), detecting parasitaemias as low as 3.7 parasites/µL (p/µL) (TBS and uRDT) compared to 5.6 p/µL (cRDT) based on TBS density measurements. TBS, uRDT and cRDT did not detect any of the 70/123 samples positive by qPCR below 5.86 p/µL, the qPCR density corresponding to 3.7 p/µL by TBS. The median prepatent periods in days (ranges) were 14.5 (10–20), 18.0 (15–28), 18.0 (15–20) and 18.0 (16–24) for qPCR, TBS, uRDT and cRDT, respectively; qPCR detected parasitaemia significantly earlier (3.5 days) than the other tests. Conclusions TBS and uRDT had similar sensitivities, both were more sensitive than cRDT, and neither matched qPCR for detecting low density parasitaemia. uRDT could be considered an alternative to TBS in selected applications, such as CHMI or field diagnosis, where qualitative, dichotomous results for malaria infection might be sufficient. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04103-y.
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Affiliation(s)
- Maxmillian Mpina
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland. .,Ifakara Health Institute, Ifakara, Tanzania.
| | - Thomas C Stabler
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Tobias Schindler
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Jose Raso
- Medical Care Development International, Malabo, Equatorial Guinea.,Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Anna Deal
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | | | - Elizabeth Nyakarungu
- Ifakara Health Institute, Ifakara, Tanzania.,Medical Care Development International, Malabo, Equatorial Guinea
| | | | - Vicente Urbano
- Medical Care Development International, Malabo, Equatorial Guinea.,Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Ali Mtoro
- Ifakara Health Institute, Ifakara, Tanzania.,Medical Care Development International, Malabo, Equatorial Guinea
| | - Ali Hamad
- Ifakara Health Institute, Ifakara, Tanzania.,Medical Care Development International, Malabo, Equatorial Guinea
| | - Maria Silvia A Lopez
- Medical Care Development International, Malabo, Equatorial Guinea.,Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Beltran Pasialo
- Medical Care Development International, Malabo, Equatorial Guinea.,Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Marta Alene Owono Eyang
- Medical Care Development International, Malabo, Equatorial Guinea.,Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Matilde Riloha Rivas
- Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | | | | | - Juan Carlos Momo
- Medical Care Development International, Malabo, Equatorial Guinea.,Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Raul Chuquiyauri
- Medical Care Development International, Malabo, Equatorial Guinea.,Sanaria Inc., 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | | | | | - B Kim Lee Sim
- Sanaria Inc., 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | | | - Marcel Tanner
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Carl Maas
- Marathon EG production Ltd., Houston, USA
| | | | | | | | - Said Jongo
- Ifakara Health Institute, Ifakara, Tanzania.,Medical Care Development International, Malabo, Equatorial Guinea
| | - Thomas L Richie
- Sanaria Inc., 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Claudia A Daubenberger
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
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8
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Kapulu MC, Njuguna P, Hamaluba M, Kimani D, Ngoi JM, Musembi J, Ngoto O, Otieno E, Billingsley PF. Safety and PCR monitoring in 161 semi-immune Kenyan adults following controlled human malaria infection. JCI Insight 2021; 6:e146443. [PMID: 34264864 PMCID: PMC8492329 DOI: 10.1172/jci.insight.146443] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 07/14/2021] [Indexed: 11/26/2022] Open
Abstract
BACKGROUNDNaturally acquired immunity to malaria is incompletely understood. We used controlled human malaria infection (CHMI) to study the impact of past exposure on malaria in Kenyan adults in relation to infection with a non-Kenyan parasite strain.METHODSWe administered 3.2 × 103 aseptic, purified, cryopreserved Plasmodium falciparum sporozoites (Sanaria PfSPZ Challenge, NF54 West African strain) by direct venous inoculation and undertook clinical monitoring and serial quantitative PCR (qPCR) of the 18S ribosomal RNA gene. The study endpoint was met when parasitemia reached 500 or more parasites per μL blood, clinically important symptoms were seen, or at 21 days after inoculation. All volunteers received antimalarial drug treatment upon meeting the endpoint.RESULTSOne hundred and sixty-one volunteers underwent CHMI between August 4, 2016, and February 14, 2018. CHMI was well tolerated, with no severe or serious adverse events. Nineteen volunteers (11.8%) were excluded from the analysis based on detection of antimalarial drugs above the minimal inhibitory concentration or parasites genotyped as non-NF54. Of the 142 volunteers who were eligible for analysis, 26 (18.3%) had febrile symptoms and were treated; 30 (21.1%) reached 500 or more parasites per μL and were treated; 53 (37.3%) had parasitemia without meeting thresholds for treatment; and 33 (23.2%) remained qPCR negative.CONCLUSIONWe found that past exposure to malaria, as evidenced by location of residence, in some Kenyan adults can completely suppress in vivo growth of a parasite strain originating from outside Kenya.TRIAL REGISTRATIONClinicalTrials.gov NCT02739763.FUNDINGWellcome Trust.
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Affiliation(s)
- Melissa C. Kapulu
- Centre for Geographic Medicine Research, Coast, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Patricia Njuguna
- Centre for Geographic Medicine Research, Coast, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Mainga Hamaluba
- Centre for Geographic Medicine Research, Coast, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Domtila Kimani
- Centre for Geographic Medicine Research, Coast, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Joyce M. Ngoi
- Centre for Geographic Medicine Research, Coast, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Janet Musembi
- Centre for Geographic Medicine Research, Coast, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Omar Ngoto
- Centre for Geographic Medicine Research, Coast, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Edward Otieno
- Centre for Geographic Medicine Research, Coast, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
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Gnangnon B, Duraisingh MT, Buckee CO. Deconstructing the parasite multiplication rate of Plasmodium falciparum. Trends Parasitol 2021; 37:922-932. [PMID: 34119440 DOI: 10.1016/j.pt.2021.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 05/05/2021] [Accepted: 05/06/2021] [Indexed: 01/22/2023]
Abstract
Epidemiological indicators describing population-level malaria transmission dynamics are widely used to guide policy recommendations. However, the determinants of malaria outcomes within individuals are still poorly understood. This conceptual gap partly reflects the fact that there are few indicators that robustly predict the trajectory of individual infections or clinical outcomes. The parasite multiplication rate (PMR) is a widely used indicator for the Plasmodium intraerythrocytic development cycle (IDC), for example, but its relationship to clinical outcomes is complex. Here, we review its calculation and use in P. falciparum malaria research, as well as the parasite and host factors that impact it. We also provide examples of metrics that can help to link within-host dynamics to malaria clinical outcomes when used alongside the PMR.
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Affiliation(s)
- Bénédicte Gnangnon
- Center for Communicable Diseases Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Immunology & Infectious Diseases Department, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Manoj T Duraisingh
- Immunology & Infectious Diseases Department, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Caroline O Buckee
- Center for Communicable Diseases Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
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10
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Goswami D, Betz W, Locham NK, Parthiban C, Brager C, Schäfer C, Camargo N, Nguyen T, Kennedy SY, Murphy SC, Vaughan AM, Kappe SH. A replication-competent late liver stage-attenuated human malaria parasite. JCI Insight 2020; 5:135589. [PMID: 32484795 DOI: 10.1172/jci.insight.135589] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 05/21/2020] [Indexed: 01/06/2023] Open
Abstract
Whole-sporozoite vaccines engender sterilizing immunity against malaria in animal models and importantly, in humans. Gene editing allows for the removal of specific parasite genes, enabling generation of genetically attenuated parasite (GAP) strains for vaccination. Using rodent malaria parasites, we have previously shown that late liver stage-arresting replication-competent (LARC) GAPs confer superior protection when compared with early liver stage-arresting replication-deficient GAPs and radiation-attenuated sporozoites. However, generating a LARC GAP in the human malaria parasite Plasmodium falciparum (P. falciparum) has been challenging. Here, we report the generation and characterization of a likely unprecedented P. falciparum LARC GAP generated by targeted gene deletion of the Mei2 gene: P. falciparum mei2-. Robust exoerythrocytic schizogony with extensive cell growth and DNA replication was observed for P. falciparum mei2- liver stages in human liver-chimeric mice. However, P. falciparum mei2- liver stages failed to complete development and did not form infectious exoerythrocytic merozoites, thereby preventing their transition to asexual blood stage infection. Therefore, P. falciparum mei2- is a replication-competent, attenuated human malaria parasite strain with potentially increased potency, useful for vaccination to protect against P. falciparum malaria infection.
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Affiliation(s)
- Debashree Goswami
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - William Betz
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Navin K Locham
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | | | - Carolyn Brager
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Carola Schäfer
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Nelly Camargo
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Thao Nguyen
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Spencer Y Kennedy
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | | | - Ashley M Vaughan
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA.,Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Stefan Hi Kappe
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA.,Department of Pediatrics, University of Washington, Seattle, Washington, USA
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11
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Recombinase Polymerase Amplification and Lateral Flow Assay for Ultrasensitive Detection of Low-Density Plasmodium falciparum Infection from Controlled Human Malaria Infection Studies and Naturally Acquired Infections. J Clin Microbiol 2020; 58:JCM.01879-19. [PMID: 32102854 DOI: 10.1128/jcm.01879-19] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 02/06/2020] [Indexed: 11/20/2022] Open
Abstract
Microscopy and rapid diagnostic tests (RDTs) are the main diagnostic tools for malaria but fail to detect low-density parasitemias that are important for maintaining malaria transmission. To complement existing diagnostic methods, an isothermal reverse transcription-recombinase polymerase amplification and lateral flow assay (RT-RPA) was developed. We compared the performance with that of ultrasensitive reverse transcription-quantitative PCR (uRT-qPCR) using nucleic acid extracts from blood samples (n = 114) obtained after standardized controlled human malaria infection (CHMI) with Plasmodium falciparum sporozoites. As a preliminary investigation, we also sampled asymptomatic individuals (n = 28) in an area of malaria endemicity (Lambaréné, Gabon) to validate RT-RPA and assess its performance with unprocessed blood samples (dbRT-RPA). In 114 samples analyzed from CHMI trials, the positive percent agreement to uRT-qPCR was 90% (95% confidence interval [CI], 80 to 96). The negative percent agreement was 100% (95% CI, 92 to 100). The lower limit of detection was 64 parasites/ml. In Gabon, RT-RPA was 100% accurate with asymptomatic volunteers (n = 28), while simplified dbRT-RPA showed 89% accuracy. In a subgroup analysis, RT-RPA detected 9/10 RT-qPCR-positive samples, while loop-mediated isothermal amplification (LAMP) detected 2/10. RT-RPA is a reliable diagnostic test for asymptomatic low-density infections. It is particularly useful in settings where uRT-qPCR is difficult to implement.
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12
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Cunningham JA, Thomson RM, Murphy SC, de la Paz Ade M, Ding XC, Incardona S, Legrand E, Lucchi NW, Menard D, Nsobya SL, Saez AC, Chiodini PL, Shrivastava J. WHO malaria nucleic acid amplification test external quality assessment scheme: results of distribution programmes one to three. Malar J 2020; 19:129. [PMID: 32228615 PMCID: PMC7106789 DOI: 10.1186/s12936-020-03200-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 03/23/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The World Health Organization (WHO) recommends parasite-based diagnosis of malaria. In recent years, there has been surge in the use of various kinds of nucleic-acid amplification based tests (NAATs) for detection and identification of Plasmodium spp. to support clinical care in high-resource settings and clinical and epidemiological research worldwide. However, these tests are not without challenges, including lack (or limited use) of standards and lack of reproducibility, due in part to variation in protocols amongst laboratories. Therefore, there is a need for rigorous quality control, including a robust external quality assessment (EQA) scheme targeted towards malaria NAATs. To this effect, the WHO Global Malaria Programme worked with the UK National External Quality Assessment Scheme (UK NEQAS) Parasitology and with technical experts to launch a global NAAT EQA scheme in January 2017. METHODS Panels of NAAT EQA specimens containing five major species of human-infecting Plasmodium at various parasite concentrations and negative samples were created in lyophilized blood (LB) and dried blood spot (DBS) formats. Two distributions per year were sent, containing five LB and five DBS specimens. Samples were tested and validated by six expert referee laboratories prior to distribution. Between 37 and 45 laboratories participated in each distribution and submitted results using the online submission portal of UK NEQAS. Participants were scored based on their laboratory's stated capacity to identify Plasmodium species, and individual laboratory reports were sent which included performance comparison with anonymized peers. RESULTS Analysis of the first three distributions revealed that the factors that most significantly affected performance were sample format (DBS vs LB), species and parasite density, while laboratory location and the reported methodology used (type of nucleic acid extraction, amplification, or DNA vs RNA target) did not significantly affect performance. Referee laboratories performed better than non-referee laboratories. CONCLUSIONS Globally, malaria NAAT assays now inform a range of clinical, epidemiological and research investigations. EQA schemes offer a way for laboratories to assess and improve their performance, which is critical to safeguarding the reliability of data and diagnoses especially in situations where various NAAT methodologies and protocols are in use.
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Affiliation(s)
| | | | - Sean C Murphy
- Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, USA
| | - Maria de la Paz Ade
- Department of Communicable Diseases and Health Analysis, Pan American Health Organization/World Health Organization, Washington, DC, USA
| | - Xavier C Ding
- Foundation for Innovative New Diagnostics, Geneva, Switzerland
| | | | - Eric Legrand
- Biology of Host-Parasite Interactions Unit, Institut Pasteur, INSERM U1201/CNRS ERL9195, Paris, France
| | - Naomi W Lucchi
- Malaria Branch, Division of Parasitic Diseases and MalariaCenter for Global Health, Centers for Disease Control and Prevention, Atlanta, USA
| | - Didier Menard
- Biology of Host-Parasite Interactions Unit, Institut Pasteur, INSERM U1201/CNRS ERL9195, Paris, France
| | - Samuel L Nsobya
- Department of Pathology, School of Biomedical Science, Makerere University, Kampala, Uganda
| | - Agatha C Saez
- UK NEQAS Parasitology, Public Health England, London, UK
| | - Peter L Chiodini
- UK NEQAS Parasitology, Public Health England, London, UK
- The Hospital for Tropical Diseases, London, UK
| | - Jaya Shrivastava
- UK NEQAS Parasitology, Public Health England, London, UK
- The Hospital for Tropical Diseases, London, UK
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13
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Assefa A, Ahmed AA, Deressa W, Wilson GG, Kebede A, Mohammed H, Sassine M, Haile M, Dilu D, Teka H, Murphy MW, Sergent S, Rogier E, Zhiyong Z, Wakeman BS, Drakeley C, Shi YP, Von Seidlein L, Hwang J. Assessment of subpatent Plasmodium infection in northwestern Ethiopia. Malar J 2020; 19:108. [PMID: 32131841 PMCID: PMC7057598 DOI: 10.1186/s12936-020-03177-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 02/22/2020] [Indexed: 12/30/2022] Open
Abstract
Background Ethiopia has set a goal for malaria elimination by 2030. Low parasite density infections may go undetected by conventional diagnostic methods (microscopy and rapid diagnostic tests) and their contribution to malaria transmission varies by transmission settings. This study quantified the burden of subpatent infections from samples collected from three regions of northwest Ethiopia. Methods Sub-samples of dried blood spots from the Ethiopian Malaria Indicator Survey 2015 (EMIS-2015) were tested and compared using microscopy, rapid diagnostic tests (RDTs), and nested polymerase chain reaction (nPCR) to determine the prevalence of subpatent infection. Paired seroprevalence results previously reported along with gender, age, and elevation of residence were explored as risk factors for Plasmodium infection. Results Of the 2608 samples collected, the highest positive rate for Plasmodium infection was found with nPCR 3.3% (95% CI 2.7–4.1) compared with RDT 2.8% (95% CI 2.2–3.5) and microscopy 1.2% (95% CI 0.8–1.7). Of the nPCR positive cases, Plasmodium falciparum accounted for 3.1% (95% CI 2.5–3.8), Plasmodium vivax 0.4% (95% CI 0.2–0.7), mixed P. falciparum and P. vivax 0.1% (95% CI 0.0–0.4), and mixed P. falciparum and Plasmodium malariae 0.1% (95% CI 0.0–0.3). nPCR detected an additional 30 samples that had not been detected by conventional methods. The majority of the nPCR positive cases (61% (53/87)) were from the Benishangul-Gumuz Region. Malaria seropositivity had significant association with nPCR positivity [adjusted OR 10.0 (95% CI 3.2–29.4), P < 0.001]. Conclusion Using nPCR the detection rate of malaria parasites increased by nearly threefold over rates based on microscopy in samples collected during a national cross-sectional survey in 2015 in Ethiopia. Such subpatent infections might contribute to malaria transmission. In addition to strengthening routine surveillance systems, malaria programmes may need to consider low-density, subpatent infections in order to accelerate malaria elimination efforts.
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Affiliation(s)
- Ashenafi Assefa
- Ethiopian Public Health Institute, Arbegnoch Street, Mail Box: 19922, Addis Ababa, Ethiopia. .,School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Ahmed Ali Ahmed
- School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia
| | - Wakgari Deressa
- School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia
| | - G Glenn Wilson
- Department of Biology, University of Southern Denmark, 5230, Odense M, Denmark
| | - Amha Kebede
- African Society for Laboratory Medicine, Addis Ababa, Ethiopia
| | - Hussein Mohammed
- Ethiopian Public Health Institute, Arbegnoch Street, Mail Box: 19922, Addis Ababa, Ethiopia
| | - Maruon Sassine
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Mebrahtom Haile
- Disease Prevention and Control Directorate, Federal Ministry of Health, Addis Ababa, Ethiopia
| | - Dereje Dilu
- Disease Prevention and Control Directorate, Federal Ministry of Health, Addis Ababa, Ethiopia
| | - Hiwot Teka
- U.S. President's Malaria Initiative, United States Agency for International Development, Addis Ababa, Ethiopia
| | - Matthew W Murphy
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, U.S. President's Malaria Initiative, Addis Ababa, Ethiopia
| | - Sheila Sergent
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Eric Rogier
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Zhou Zhiyong
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Brian S Wakeman
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Chris Drakeley
- London School of Hygiene and Tropical Medicine, London, UK
| | - Ya Ping Shi
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | | | - Jimee Hwang
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, U.S. President's Malaria Initiative, Atlanta, GA, USA
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14
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Seilie AM, Chang M, Hanron AE, Billman ZP, Stone BC, Zhou K, Olsen TM, Daza G, Ortega J, Cruz KR, Smith N, Healy SA, Neal J, Wallis CK, Shelton L, Mankowski TV, Wong-Madden S, Mikolajczak SA, Vaughan AM, Kappe SHI, Fishbaugher M, Betz W, Kennedy M, Hume JCC, Talley AK, Hoffman SL, Chakravarty S, Sim BKL, Richie TL, Wald A, Plowe CV, Lyke KE, Adams M, Fahle GA, Cowan EP, Duffy PE, Kublin JG, Murphy SC. Beyond Blood Smears: Qualification of Plasmodium 18S rRNA as a Biomarker for Controlled Human Malaria Infections. Am J Trop Med Hyg 2020; 100:1466-1476. [PMID: 31017084 PMCID: PMC6553913 DOI: 10.4269/ajtmh.19-0094] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
18S rRNA is a biomarker that provides an alternative to thick blood smears in controlled human malaria infection (CHMI) trials. We reviewed data from CHMI trials at non-endemic sites that used blood smears and Plasmodium 18S rRNA/rDNA biomarker nucleic acid tests (NATs) for time to positivity. We validated a multiplex quantitative reverse transcription–polymerase chain reaction (qRT-PCR) for Plasmodium 18S rRNA, prospectively compared blood smears and qRT-PCR for three trials, and modeled treatment effects at different biomarker-defined parasite densities to assess the impact on infection detection, symptom reduction, and measured intervention efficacy. Literature review demonstrated accelerated NAT-based infection detection compared with blood smears (mean acceleration: 3.2–3.6 days). For prospectively tested trials, the validated Plasmodium 18S rRNA qRT-PCR positivity was earlier (7.6 days; 95% CI: 7.1–8.1 days) than blood smears (11.0 days; 95% CI: 10.3–11.8 days) and significantly preceded the onset of grade 2 malaria-related symptoms (12.2 days; 95% CI: 10.6–13.3 days). Discrepant analysis showed that the risk of a blood smear–positive, biomarker-negative result was negligible. Data modeling predicted that treatment triggered by specific biomarker-defined thresholds can differentiate complete, partial, and non-protective outcomes and eliminate many grade 2 and most grade 3 malaria-related symptoms post-CHMI. Plasmodium 18S rRNA is a sensitive and specific biomarker that can justifiably replace blood smears for infection detection in CHMI trials in non-endemic settings. This study led to biomarker qualification through the U.S. Food and Drug Administration for use in CHMI studies at non-endemic sites, which will facilitate biomarker use for the qualified context of use in drug and vaccine trials.
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Affiliation(s)
- Annette M Seilie
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Ming Chang
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Amelia E Hanron
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Zachary P Billman
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Brad C Stone
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Kevin Zhou
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Tayla M Olsen
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Glenda Daza
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Jose Ortega
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Kurtis R Cruz
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Nahum Smith
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Sara A Healy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.,Division of Pediatric Infectious Diseases, Department of Pediatrics, University of Washington, Seattle, Washington.,Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | - Jillian Neal
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Carolyn K Wallis
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Lisa Shelton
- Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | - Tracie VonGoedert Mankowski
- Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | - Sharon Wong-Madden
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Sebastian A Mikolajczak
- Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | - Ashley M Vaughan
- Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | - Stefan H I Kappe
- Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | - Matt Fishbaugher
- Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | - Will Betz
- Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | - Mark Kennedy
- Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | - Jen C C Hume
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Angela K Talley
- Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | | | | | | | | | - Anna Wald
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington
| | | | - Kirsten E Lyke
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Matthew Adams
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Gary A Fahle
- Microbiology Service, Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland
| | | | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - James G Kublin
- Seattle Malaria Clinical Trials Center, Fred Hutch Cancer Research Center, Seattle, Washington.,Vaccine and Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Sean C Murphy
- Department of Microbiology, University of Washington, Seattle, Washington.,Seattle Malaria Clinical Trials Center, Fred Hutch Cancer Research Center, Seattle, Washington.,Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington.,Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
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15
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Simultaneous Quantification of Plasmodium Antigens and Host Factor C-Reactive Protein in Asymptomatic Individuals with Confirmed Malaria by Use of a Novel Multiplex Immunoassay. J Clin Microbiol 2019; 57:JCM.00948-18. [PMID: 30404944 PMCID: PMC6322473 DOI: 10.1128/jcm.00948-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 10/29/2018] [Indexed: 12/14/2022] Open
Abstract
Malaria rapid diagnostic tests (RDTs) primarily detect Plasmodium falciparum antigen histidine-rich protein 2 (HRP2) and the malaria-conserved antigen lactate dehydrogenase (LDH) for P. vivax and other malaria species. The performance of RDTs and their utility is dependent on circulating antigen concentration distributions in infected individuals in a population in which malaria is endemic and on the limit of detection of the RDT for the antigens. Malaria rapid diagnostic tests (RDTs) primarily detect Plasmodium falciparum antigen histidine-rich protein 2 (HRP2) and the malaria-conserved antigen lactate dehydrogenase (LDH) for P. vivax and other malaria species. The performance of RDTs and their utility is dependent on circulating antigen concentration distributions in infected individuals in a population in which malaria is endemic and on the limit of detection of the RDT for the antigens. A multiplexed immunoassay for the quantification of HRP2, P. vivax LDH, and all-malaria LDH (pan LDH) was developed to accurately measure circulating antigen concentration and antigen distribution in a population with endemic malaria. The assay also measures C-reactive protein (CRP) levels as an indicator of inflammation. Validation was conducted with clinical specimens from 397 asymptomatic donors from Myanmar and Uganda, confirmed by PCR for infection, and from participants in induced blood-stage malaria challenge studies. The assay lower limits of detection for HRP2, pan LDH, P. vivax LDH, and CRP were 0.2 pg/ml, 9.3 pg/ml, 1.5 pg/ml, and 26.6 ng/ml, respectively. At thresholds for HRP2, pan LDH, and P. vivax LDH of 2.3 pg/ml, 47.8 pg/ml, and 75.1 pg/ml, respectively, and a specificity ≥98.5%, the sensitivities for ultrasensitive PCR-confirmed infections were 93.4%, 84.9%, and 48.9%, respectively. Plasmodium LDH (pLDH) concentration, in contrast to that of HRP2, correlated closely with parasite density. CRP levels were moderately higher in P. falciparum infections with confirmed antigenemia versus those in clinical specimens with no antigen. The 4-plex array is a sensitive tool for quantifying diagnostic antigens in malaria infections and supporting the evaluation of new ultrasensitive RDTs.
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16
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Olsen TM, Stone BC, Chuenchob V, Murphy SC. Prime-and-Trap Malaria Vaccination To Generate Protective CD8 + Liver-Resident Memory T Cells. THE JOURNAL OF IMMUNOLOGY 2018; 201:1984-1993. [PMID: 30127085 DOI: 10.4049/jimmunol.1800740] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 08/02/2018] [Indexed: 11/19/2022]
Abstract
Tissue-resident memory CD8+ T (Trm) cells in the liver are critical for long-term protection against pre-erythrocytic Plasmodium infection. Such protection can usually be induced with three to five doses of i.v. administered radiation-attenuated sporozoites (RAS). To simplify and accelerate vaccination, we tested a DNA vaccine designed to induce potent T cell responses against the SYVPSAEQI epitope of Plasmodium yoelii circumsporozoite protein. In a heterologous "prime-and-trap" regimen, priming using gene gun-administered DNA and boosting with one dose of RAS attracted expanding Ag-specific CD8+ T cell populations to the liver, where they became Trm cells. Vaccinated in this manner, BALB/c mice were completely protected against challenge, an outcome not reliably achieved following one dose of RAS or following DNA-only vaccination. This study demonstrates that the combination of CD8+ T cell priming by DNA and boosting with liver-homing RAS enhances formation of a completely protective liver Trm cell response and suggests novel approaches for enhancing T cell-based pre-erythrocytic malaria vaccines.
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Affiliation(s)
- Tayla M Olsen
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98109.,Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, WA 98109
| | - Brad C Stone
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98109.,Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, WA 98109
| | - Vorada Chuenchob
- Center for Infectious Disease Research, University of Washington, Seattle, WA 98109; and
| | - Sean C Murphy
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98109; .,Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, WA 98109.,Department of Microbiology, University of Washington, Seattle, WA 98195
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17
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Murphy SC, Ishizuka AS, Billman ZP, Olsen TM, Seilie AM, Chang M, Smith N, Chuenchob V, Chakravarty S, Sim BKL, Kappe SHI, Hoffman SL, Seder RA. Plasmodium 18S rRNA of intravenously administered sporozoites does not persist in peripheral blood. Malar J 2018; 17:275. [PMID: 30053881 PMCID: PMC6062992 DOI: 10.1186/s12936-018-2422-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 07/19/2018] [Indexed: 01/14/2023] Open
Abstract
Background Plasmodium 18S rRNA is a biomarker used to monitor blood-stage infections in malaria clinical trials. Plasmodium sporozoites also express this biomarker, and there is conflicting evidence about how long sporozoite-derived 18S rRNA persists in peripheral blood. If present in blood for an extended timeframe, sporozoite-derived 18S rRNA could complicate use as a blood-stage biomarker. Methods Blood samples from Plasmodium yoelii infected mice were tested for Plasmodium 18S rRNA and their coding genes (rDNA) using sensitive quantitative reverse transcription PCR and quantitative PCR assays, respectively. Blood and tissues from Plasmodium falciparum sporozoite (PfSPZ)-infected rhesus macaques were similarly tested. Results In mice, when P. yoelii sporozoite inoculation and blood collection were performed at the same site (tail vein), low level rDNA positivity persisted for 2 days post-infection. Compared to intact parasites with high rRNA-to-rDNA ratios, this low level positivity was accompanied by no increase in rRNA-to-rDNA, indicating detection of residual, non-viable parasite rDNA. When P. yoelii sporozoites were administered via the retro-orbital vein and blood sampled by cardiac puncture, neither P. yoelii 18S rRNA nor rDNA were detected 24 h post-infection. Similarly, there was no P. falciparum 18S rRNA detected in blood of rhesus macaques 3 days after intravenous injection with extremely high doses of PfSPZ. Plasmodium 18S rRNA in the rhesus livers increased by approximately 101-fold from 3 to 6 days post infection, indicating liver-stage proliferation. Conclusions Beyond the first few hours after injection, sporozoite-derived Plasmodium 18S rRNA was not detected in peripheral blood. Diagnostics based on 18S rRNA are unlikely to be confounded by sporozoite inocula in human clinical trials.
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Affiliation(s)
- Sean C Murphy
- Departments of Laboratory Medicine and Microbiology, University of Washington, 750 Republican St., E630, Seattle, WA, 98109, USA. .,Center for Emerging and Re-emerging Infectious Diseases, University of Washington, 750 Republican St., Seattle, WA, 98109, USA.
| | - Andrew S Ishizuka
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Building 40, Room 3512, 40 Convent Drive, Bethesda, MD, 20814, USA
| | - Zachary P Billman
- Departments of Laboratory Medicine and Microbiology, University of Washington, 750 Republican St., E630, Seattle, WA, 98109, USA
| | - Tayla M Olsen
- Departments of Laboratory Medicine and Microbiology, University of Washington, 750 Republican St., E630, Seattle, WA, 98109, USA
| | - Annette M Seilie
- Departments of Laboratory Medicine and Microbiology, University of Washington, 750 Republican St., E630, Seattle, WA, 98109, USA
| | - Ming Chang
- Departments of Laboratory Medicine and Microbiology, University of Washington, 750 Republican St., E630, Seattle, WA, 98109, USA
| | - Nahum Smith
- Departments of Laboratory Medicine and Microbiology, University of Washington, 750 Republican St., E630, Seattle, WA, 98109, USA
| | - Vorada Chuenchob
- Center for Infectious Disease Research, 307 Westlake Ave N #500, Seattle, WA, 98109, USA
| | - Sumana Chakravarty
- Sanaria, Inc., 9800 Medical Center Drive, Suite A209, Rockville, MD, 20850, USA
| | - B Kim Lee Sim
- Sanaria, Inc., 9800 Medical Center Drive, Suite A209, Rockville, MD, 20850, USA
| | - Stefan H I Kappe
- Center for Infectious Disease Research, 307 Westlake Ave N #500, Seattle, WA, 98109, USA
| | - Stephen L Hoffman
- Sanaria, Inc., 9800 Medical Center Drive, Suite A209, Rockville, MD, 20850, USA
| | - Robert A Seder
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Building 40, Room 3512, 40 Convent Drive, Bethesda, MD, 20814, USA
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18
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Lell B, Mordmüller B, Dejon Agobe JC, Honkpehedji J, Zinsou J, Mengue JB, Loembe MM, Adegnika AA, Held J, Lalremruata A, Nguyen TT, Esen M, KC N, Ruben AJ, Chakravarty S, Lee Sim BK, Billingsley PF, James ER, Richie TL, Hoffman SL, Kremsner PG. Impact of Sickle Cell Trait and Naturally Acquired Immunity on Uncomplicated Malaria after Controlled Human Malaria Infection in Adults in Gabon. Am J Trop Med Hyg 2018; 98:508-515. [PMID: 29260650 PMCID: PMC5929186 DOI: 10.4269/ajtmh.17-0343] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Accepted: 11/02/2017] [Indexed: 11/07/2022] Open
Abstract
Controlled human malaria infection (CHMI) by direct venous inoculation (DVI) with 3,200 cryopreserved Plasmodium falciparum sporozoites (PfSPZ) consistently leads to parasitemia and malaria symptoms in malaria-naive adults. We used CHMI by DVI to investigate infection rates, parasite kinetics, and malaria symptoms in lifelong malaria-exposed (semi-immune) Gabonese adults with and without sickle cell trait. Eleven semi-immune Gabonese with normal hemoglobin (IA), nine with sickle cell trait (IS), and five nonimmune European controls with normal hemoglobin (NI) received 3,200 PfSPZ by DVI and were followed 28 days for parasitemia by thick blood smear (TBS) and quantitative polymerase chain reaction (qPCR) and for malaria symptoms. End points were time to parasitemia and parasitemia plus symptoms. PfSPZ Challenge was well tolerated and safe. Five of the five (100%) NI, 7/11 (64%) IA, and 5/9 (56%) IS volunteers developed parasitemia by TBS, and 5/5 (100%) NI, 9/11 (82%) IA, and 7/9 (78%) IS by qPCR, respectively. The time to parasitemia by TBS was longer in IA (geometric mean 16.9 days) and IS (19.1 days) than in NA (12.6 days) volunteers (P = 0.016, 0.021, respectively). Five of the five, 6/9, and 1/7 volunteers with parasitemia developed symptoms (P = 0.003, NI versus IS). Naturally adaptive immunity (NAI) to malaria significantly prolonged the time to parasitemia. Sickle cell trait seemed to prolong it further. NAI plus sickle cell trait, but not NAI alone, significantly reduced symptom rate. Twenty percent (4/20) semi-immunes demonstrated sterile protective immunity. Standardized CHMI with PfSPZ Challenge is a powerful tool for dissecting the impact of innate and naturally acquired adaptive immunity on malaria.
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Affiliation(s)
- Bertrand Lell
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen and German Center for Infection Research (DZIF), Tübingen, Germany
| | - Benjamin Mordmüller
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen and German Center for Infection Research (DZIF), Tübingen, Germany
| | | | | | - Jeannot Zinsou
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | - Juliana Boex Mengue
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen and German Center for Infection Research (DZIF), Tübingen, Germany
| | | | - Ayola Akim Adegnika
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen and German Center for Infection Research (DZIF), Tübingen, Germany
| | - Jana Held
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen and German Center for Infection Research (DZIF), Tübingen, Germany
| | - Albert Lalremruata
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen and German Center for Infection Research (DZIF), Tübingen, Germany
| | - The Trong Nguyen
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen and German Center for Infection Research (DZIF), Tübingen, Germany
| | - Meral Esen
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen and German Center for Infection Research (DZIF), Tübingen, Germany
| | - Natasha KC
- Sanaria Inc., Rockville, Maryland
- Protein Potential, LLC, Rockville, Maryland
| | | | | | | | | | | | | | - Stephen L. Hoffman
- Sanaria Inc., Rockville, Maryland
- Protein Potential, LLC, Rockville, Maryland
| | - Peter G. Kremsner
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen and German Center for Infection Research (DZIF), Tübingen, Germany
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19
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Roestenberg M, Mordmüller B, Ockenhouse C, Mo A, Yazdanbakhsh M, Kremsner PG. The frontline of controlled human malaria infections: A report from the controlled human infection models Workshop in Leiden University Medical Centre 5 May 2016. Vaccine 2017; 35:7065-7069. [PMID: 29153778 DOI: 10.1016/j.vaccine.2017.10.093] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 10/30/2017] [Accepted: 10/31/2017] [Indexed: 12/22/2022]
Abstract
Controlled Human Malaria Infection (CHMI) is the most practiced controlled human infection model nowadays and there is an exponential increase in implementation of the model worldwide. During the Controlled Human Infection Models Workshop in Leiden, one day was dedicated to the discussion of the advances made and gaps in Controlled Human Malaria Infection (CHMI) trials. Factors contributing to this impressive expansion in the number of CHMI trials have been related to the ability to perform CHMI using injectable cryopreserved sporozoites (a product from Sanaria Inc. - PfSPZ Challenge), the development of a transmission blocking CHMI model and the need to test more vaccine candidates particularly in the field of whole-sporozoite vaccine development. However, with an increasing number of CHMI trials being undertaken, in an ever-growing number of trial sites, heterogeneity in trial design may compromise universal interpretation of results and require an ongoing dialogue on the need and feasibility of standardization. At the workshop, CHMI investigators convened to share their experiences in CHMI trials and discuss the possibilities for future trials.
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Affiliation(s)
| | - Benjamin Mordmüller
- Universitätsklinikum Tübingen, Germany and Centre de Recherches Médicales de Lambaréné, Gabon
| | | | - Annie Mo
- Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, USA
| | | | - Peter G Kremsner
- Universitätsklinikum Tübingen, Germany and Centre de Recherches Médicales de Lambaréné, Gabon
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20
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Sack BK, Mikolajczak SA, Fishbaugher M, Vaughan AM, Flannery EL, Nguyen T, Betz W, Jane Navarro M, Foquet L, Steel RWJ, Billman ZP, Murphy SC, Hoffman SL, Chakravarty S, Sim BKL, Behet M, Reuling IJ, Walk J, Scholzen A, Sauerwein RW, Ishizuka AS, Flynn B, Seder RA, Kappe SHI. Humoral protection against mosquito bite-transmitted Plasmodium falciparum infection in humanized mice. NPJ Vaccines 2017; 2:27. [PMID: 29263882 PMCID: PMC5634440 DOI: 10.1038/s41541-017-0028-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Revised: 07/25/2017] [Accepted: 09/07/2017] [Indexed: 01/05/2023] Open
Abstract
A malaria vaccine that prevents infection will be an important new tool in continued efforts of malaria elimination, and such vaccines are under intense development for the major human malaria parasite Plasmodium falciparum (Pf). Antibodies elicited by vaccines can block the initial phases of parasite infection when sporozoites are deposited into the skin by mosquito bite and then target the liver for further development. However, there are currently no standardized in vivo preclinical models that can measure the inhibitory activity of antibody specificities against Pf sporozoite infection via mosquito bite. Here, we use human liver-chimeric mice as a challenge model to assess prevention of natural Pf sporozoite infection by antibodies. We demonstrate that these mice are consistently infected with Pf by mosquito bite and that this challenge can be combined with passive transfer of either monoclonal antibodies or polyclonal human IgG from immune serum to measure antibody-mediated blocking of parasite infection using bioluminescent imaging. This methodology is useful to down-select functional antibodies and to investigate mechanisms or immune correlates of protection in clinical trials, thereby informing rational vaccine optimization.
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Affiliation(s)
| | | | | | | | | | - Thao Nguyen
- Center for Infectious Disease Research, Seattle, WA USA
| | - Will Betz
- Center for Infectious Disease Research, Seattle, WA USA
| | | | - Lander Foquet
- Center for Infectious Disease Research, Seattle, WA USA
| | | | - Zachary P. Billman
- Departments of Laboratory Medicine and Microbiology and the Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, WA USA
| | - Sean C. Murphy
- Center for Infectious Disease Research, Seattle, WA USA
- Departments of Laboratory Medicine and Microbiology and the Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, WA USA
| | | | | | | | | | | | - Jona Walk
- Radboud University, Nijmegen, The Netherlands
| | | | | | | | | | | | - Stefan H. I. Kappe
- Center for Infectious Disease Research, Seattle, WA USA
- Department of Global Health, University of Washington, Seattle, WA USA
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21
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Das S, Jang IK, Barney B, Peck R, Rek JC, Arinaitwe E, Adrama H, Murphy M, Imwong M, Ling CL, Proux S, Haohankhunnatham W, Rist M, Seilie AM, Hanron A, Daza G, Chang M, Nakamura T, Kalnoky M, Labarre P, Murphy SC, McCarthy JS, Nosten F, Greenhouse B, Allauzen S, Domingo GJ. Performance of a High-Sensitivity Rapid Diagnostic Test for Plasmodium falciparum Malaria in Asymptomatic Individuals from Uganda and Myanmar and Naive Human Challenge Infections. Am J Trop Med Hyg 2017; 97:1540-1550. [PMID: 28820709 PMCID: PMC5817764 DOI: 10.4269/ajtmh.17-0245] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Sensitive field-deployable diagnostic tests can assist malaria programs in achieving elimination. The performance of a new Alere™ Malaria Ag P.f Ultra Sensitive rapid diagnostic test (uRDT) was compared with the currently available SD Bioline Malaria Ag P.f RDT in blood specimens from asymptomatic individuals in Nagongera, Uganda, and in a Karen Village, Myanmar, representative of high- and low-transmission areas, respectively, as well as in pretreatment specimens from study participants from four Plasmodium falciparum-induced blood-stage malaria (IBSM) studies. A quantitative reverse transcription PCR (qRT-PCR) and a highly sensitive enzyme-linked immunosorbent assay (ELISA) test for histidine-rich protein II (HRP2) were used as reference assays. The uRDT showed a greater than 10-fold lower limit of detection for HRP2 compared with the RDT. The sensitivity of the uRDT was 84% and 44% against qRT-PCR in Uganda and Myanmar, respectively, and that of the RDT was 62% and 0% for the same two sites. The specificities of the uRDT were 92% and 99.8% against qRT-PCR for Uganda and Myanmar, respectively, and 99% and 99.8% against the HRP2 reference ELISA. The RDT had specificities of 95% and 100% against qRT-PCR for Uganda and Myanmar, respectively, and 96% and 100% against the HRP2 reference ELISA. The uRDT detected new infections in IBSM study participants 1.5 days sooner than the RDT. The uRDT has the same workflow as currently available RDTs, but improved performance characteristics to identify asymptomatic malaria infections. The uRDT may be a useful tool for malaria elimination strategies.
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Affiliation(s)
- Smita Das
- Diagnostics Program, PATH, Seattle, Washington
| | | | | | - Roger Peck
- Diagnostics Program, PATH, Seattle, Washington
| | - John C Rek
- Infectious Disease Research Collaboration, Kampala, Uganda
| | | | - Harriet Adrama
- Infectious Disease Research Collaboration, Kampala, Uganda
| | - Maxwell Murphy
- University of California San Francisco, San Francisco, California
| | - Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Clare L Ling
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Stephane Proux
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Warat Haohankhunnatham
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Melissa Rist
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Annette M Seilie
- Department of Laboratory Medicine, University of Washington, Seattle, Washington
| | - Amelia Hanron
- Department of Laboratory Medicine, University of Washington, Seattle, Washington
| | - Glenda Daza
- Department of Laboratory Medicine, University of Washington, Seattle, Washington
| | - Ming Chang
- Department of Laboratory Medicine, University of Washington, Seattle, Washington
| | | | | | | | - Sean C Murphy
- Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington.,Department of Microbiology, University of Washington, Seattle, Washington.,Department of Laboratory Medicine, University of Washington, Seattle, Washington
| | | | - Francois Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom.,Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Bryan Greenhouse
- University of California San Francisco, San Francisco, California
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22
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A sensitive species-specific reverse transcription real-time PCR method for detection of Plasmodium falciparum and Plasmodium vivax. Parasite Epidemiol Control 2017; 2:70-76. [PMID: 29774283 PMCID: PMC5952667 DOI: 10.1016/j.parepi.2017.04.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 04/05/2017] [Accepted: 04/05/2017] [Indexed: 11/25/2022] Open
Abstract
As the global burden of malaria decreases and countries strive towards disease elimination, there is a greater demand for sensitive diagnostics to target the submicroscopic reservoir of infection. We describe here a sensitive species-specific RT-qPCR method to differentiate between Plasmodium falciparum and P. vivax infections at the submicroscopic level. With amplification of the 18S rRNA genes from total nucleic acids (both DNA and RNA), we discern P. falciparum and P. vivax with a limit of detection of 10 parasites/mL and 18 copies/μL, respectively. This assay was validated with 519 blood samples, negative by thick-smear, from febrile and asymptomatic cohorts from Colombia. These results were directly compared to a qPCR-based method (DNA only) as the gold standard. Of the samples from patients who presented with fever (n = 274), 34 infections were identified by RT-qPCR (16 P. falciparum, 15 P. vivax, and 3 mixed), of which only 10 infections were identified at the species level by qPCR. Within the asymptomatic cohort (n = 245), 13 infections were identified by RT-qPCR (3 P. falciparum, 3 P. vivax, and 7 mixed), whereas the species for only one infection was determined by qPCR. We conclude that this species-specific RT-qPCR method provides a more sensitive tool for species identification compared to DNA based qPCR methods.
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23
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Hanron AE, Billman ZP, Seilie AM, Chang M, Murphy SC. Detection of Babesia microti parasites by highly sensitive 18S rRNA reverse transcription PCR. Diagn Microbiol Infect Dis 2016; 87:226-228. [PMID: 27986353 DOI: 10.1016/j.diagmicrobio.2016.11.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/29/2016] [Accepted: 11/30/2016] [Indexed: 11/20/2022]
Abstract
Babesia are increasingly appreciated as a cause of transfusion-transmitted infection. Sensitive methods are needed to screen blood products. We report herein that B. microti 18S rRNA is over 1,000-fold more abundant than its coding genes, making reverse transcription PCR (RT-PCR) much more sensitive than PCR. Babesia 18S rRNA may be useful for screening the blood supply.
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Affiliation(s)
- Amelia E Hanron
- Department of Laboratory Medicine, University of Washington, Seattle, WA, USA
| | - Zachary P Billman
- Department of Laboratory Medicine, University of Washington, Seattle, WA, USA; Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, WA, USA
| | - Annette M Seilie
- Department of Laboratory Medicine, University of Washington, Seattle, WA, USA
| | - Ming Chang
- Department of Laboratory Medicine, University of Washington, Seattle, WA, USA
| | - Sean C Murphy
- Department of Laboratory Medicine, University of Washington, Seattle, WA, USA; Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, WA, USA; Department of Microbiology, University of Washington, Seattle, WA, USA.
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24
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Kemleu S, Guelig D, Eboumbou Moukoko C, Essangui E, Diesburg S, Mouliom A, Melingui B, Manga J, Donkeu C, Epote A, Texier G, LaBarre P, Burton R, Ayong L. A Field-Tailored Reverse Transcription Loop-Mediated Isothermal Assay for High Sensitivity Detection of Plasmodium falciparum Infections. PLoS One 2016; 11:e0165506. [PMID: 27824866 PMCID: PMC5100904 DOI: 10.1371/journal.pone.0165506] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 10/13/2016] [Indexed: 11/19/2022] Open
Abstract
Highly sensitive and field deployable molecular diagnostic tools are critically needed for detecting submicroscopic, yet transmissible levels of malaria parasites prevalent in malaria endemic countries worldwide. A reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed and evaluated in comparison with thick blood smear microscopy, an antigen-based rapid diagnostic test (RDT), and an in-house RT-PCR targeting the same RT-LAMP transcript. The optimized assay detected Plasmodium falciparum infections in as little as 0.25ng of total parasite RNA, and exhibited a detection limit of 0.08 parasites/ μL when tested directly on infected whole blood lysates, or ~0.0008 parasites/ μL when using RNA extracts. Assay positivity was observed as early as eight minutes from initiation of the RT-LAMP and in most cases the reaction was complete before twenty minutes. Clinical evaluation of the assay on 132 suspected malaria cases resulted in a positivity rate of 90% for RT-LAMP using extracted RNA, and 85% when using whole blood lysates. The positivity rates were 70% for P. falciparum-specific RDT, 83% for RT-PCR, and 74% for thick blood smear microscopy (Mean parasite density = 36,986 parasites/ μL). Concordance rates between the developed RT-LAMP and comparator tests were greater than 75%, the lowest being with light microscopy (78%, McNemar's test: P = 0.0002), and the highest was with RT-PCR (87%, McNemar's test: P = 0.0523). Compared to reference RT-PCR, assay sensitivity was 90% for RT-LAMP on whole blood, and 96% for RT-LAMP using corresponding RNA extracts. Electricity-free heaters were further developed and evaluated in comparison with a battery-operated isothermal amplification machine for use with the developed test in resource-limited settings. Taken together, the data highlight the benefits of targeting high abundant RNA transcripts in molecular diagnosis, as well as the potential usefulness of the developed RT-LAMP-assay in malaria diagnosis in low to high parasite density settings.
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Affiliation(s)
- Sylvie Kemleu
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaoundé, Cameroon
| | - Dylan Guelig
- PATH, Seattle, Washington, United States of America
| | - Carole Eboumbou Moukoko
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaoundé, Cameroon
- Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
| | - Estelle Essangui
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaoundé, Cameroon
- Faculty of Sciences, University of Douala, Douala, Cameroon
| | | | - Abas Mouliom
- Hematology Unit, Centre Pasteur du Cameroun, Yaoundé, Cameroon
| | | | - Jeanne Manga
- Hematology Unit, Centre Pasteur du Cameroun, Yaoundé, Cameroon
| | - Christiane Donkeu
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaoundé, Cameroon
| | - Annie Epote
- Hematology Unit, Centre Pasteur du Cameroun, Yaoundé, Cameroon
| | - Gaëtan Texier
- Public Health & Epidemiology Unit, Centre Pasteur du Cameroun, Yaoundé, Cameroon
| | - Paul LaBarre
- PATH, Seattle, Washington, United States of America
| | | | - Lawrence Ayong
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaoundé, Cameroon
- * E-mail:
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25
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Schlappi TS, McCalla SE, Schoepp NG, Ismagilov RF. Flow-through Capture and in Situ Amplification Can Enable Rapid Detection of a Few Single Molecules of Nucleic Acids from Several Milliliters of Solution. Anal Chem 2016; 88:7647-53. [PMID: 27429181 DOI: 10.1021/acs.analchem.6b01485] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Detecting nucleic acids (NAs) at zeptomolar concentrations (few molecules per milliliter) currently requires expensive equipment and lengthy processing times to isolate and concentrate the NAs into a volume that is amenable to amplification processes, such as PCR or LAMP. Shortening the time required to concentrate NAs and integrating this procedure with amplification on-device would be invaluable to a number of analytical fields, including environmental monitoring and clinical diagnostics. Microfluidic point-of-care (POC) devices have been designed to address these needs, but they are not able to detect NAs present in zeptomolar concentrations in short time frames because they require slow flow rates and/or they are unable to handle milliliter-scale volumes. In this paper, we theoretically and experimentally investigate a flow-through capture membrane that solves this problem by capturing NAs with high sensitivity in a short time period, followed by direct detection via amplification. Theoretical predictions guided the choice of physical parameters for a chitosan-coated nylon membrane; these predictions can also be applied generally to other capture situations with different requirements. The membrane is also compatible with in situ amplification, which, by eliminating an elution step enables high sensitivity and will facilitate integration of this method into sample-to-answer detection devices. We tested a wide range of combinations of sample volumes and concentrations of DNA molecules using a capture membrane with a 2 mm radius. We show that for nucleic acid detection, this approach can concentrate and detect as few as ∼10 molecules of DNA with flow rates as high as 1 mL/min, handling samples as large as 50 mL. In a specific example, this method reliably concentrated and detected ∼25 molecules of DNA from 50 mL of sample.
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Affiliation(s)
- Travis S Schlappi
- Division of Chemistry and Chemical Engineering, California Institute of Technology , 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Stephanie E McCalla
- Division of Chemistry and Chemical Engineering, California Institute of Technology , 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Nathan G Schoepp
- Division of Chemistry and Chemical Engineering, California Institute of Technology , 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Rustem F Ismagilov
- Division of Chemistry and Chemical Engineering, California Institute of Technology , 1200 East California Boulevard, Pasadena, California 91125, United States
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26
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Elbadry MA, Al-Khedery B, Tagliamonte MS, Yowell CA, Raccurt CP, Existe A, Boncy J, Weppelmann TA, Beau De Rochars VEM, Lemoine JF, Okech BA, Dame JB. High prevalence of asymptomatic malaria infections: a cross-sectional study in rural areas in six departments in Haiti. Malar J 2015; 14:510. [PMID: 26689195 PMCID: PMC4687167 DOI: 10.1186/s12936-015-1051-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 12/12/2015] [Indexed: 11/25/2022] Open
Abstract
Background Public health measures are poised for transition from malaria control to malaria elimination on the island of Hispaniola. Assessment of the reservoir of asymptomatic infections from which acute malaria cases may derive is critical to plan and evaluate elimination efforts. Current field technology is ill suited for detecting sub-microscopic infections, thus highly sensitive survey methods capable of detecting virtually all infections are needed. In this study the prevalence of infection with Plasmodium falciparum was determined in patients seeking medical care primarily for non-febrile conditions in six departments in Haiti using a newly designed qRT-PCR-based assay. Methods Three different methods of parasite detection were compared to assess their utility in approximating the prevalence of P. falciparum infections in the population: malaria rapid diagnostic test (RDT) designed to detect histidine-rich protein 2 (HRP2), thick smear microscopy, and a quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay based upon the small sub-unit ribosomal RNA. The limit of detection of the qRT-PCR assay utilized was 0.0003 parasite/µL of blood. Venous blood was obtained from a total of 563 subjects from six departments in Haiti, all of whom were seeking medical attention without complaints consistent with malaria. Each subject was questioned for knowledge and behaviour using demographic and epidemiological survey to identify risk factors for disease transmission. Results Among the 563 samples tested, ten and 16 were found positive for malaria by RDT and microscopy, respectively. Using the qRT-PCR test to assess the infection status of these subjects, an additional 92 were identified for a total of 108. Based upon the qRT-PCR assay results, a wide variation in prevalence of infection in asymptomatic subjects was seen between geographic locations ranging from 4–41 %. The prevalence of infection was highest in the Grand Anse, Nord and Sud-Est Departments, and demographic data from questionnaires provide evidence for focal disease transmission. Conclusions The qRT-PCR assay is sufficiently sensitive to identify an unexpectedly large number of asymptomatic, submicroscopic infections. Identifying and clearing these infections presents a significant challenge to both control and elimination efforts, but the qRT-PCR assay offers a reliable method to identify them.
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Affiliation(s)
- Maha A Elbadry
- Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, USA. .,Emerging Pathogen Institute, University of Florida, Gainesville, FL, USA.
| | - Basima Al-Khedery
- Interdisciplinary Center for Biotechnology Research (ICBR), University of Florida, Gainesville, USA.
| | - Massimiliano S Tagliamonte
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, USA.
| | - Charles A Yowell
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, USA.
| | - Christian P Raccurt
- Laboratoire National de Santé Publique (LNSP), Ministère de la Santé Publique et de la Population (MSPP), Port-au-Prince, Haiti.
| | - Alexandre Existe
- Laboratoire National de Santé Publique (LNSP), Ministère de la Santé Publique et de la Population (MSPP), Port-au-Prince, Haiti.
| | - Jacques Boncy
- Laboratoire National de Santé Publique (LNSP), Ministère de la Santé Publique et de la Population (MSPP), Port-au-Prince, Haiti.
| | - Thomas A Weppelmann
- Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, USA. .,Emerging Pathogen Institute, University of Florida, Gainesville, FL, USA.
| | - Valery E M Beau De Rochars
- Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, USA. .,Emerging Pathogen Institute, University of Florida, Gainesville, FL, USA. .,Department of Health Services Research, Management and Policy, College of Public Health and Health Professions, University of Florida, Gainesville, USA.
| | - Jean F Lemoine
- Programme National de Contrôle de la Malaria, Port-au-Prince, Haiti.
| | - Bernard A Okech
- Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, USA. .,Emerging Pathogen Institute, University of Florida, Gainesville, FL, USA.
| | - John B Dame
- Emerging Pathogen Institute, University of Florida, Gainesville, FL, USA. .,Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, USA.
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27
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Viebig NK, D'Alessio F, Draper SJ, Sim BKL, Mordmüller B, Bowyer PW, Luty AJF, Jungbluth S, Chitnis CE, Hill AVS, Kremsner P, Craig AG, Kocken CHM, Leroy O. Workshop report: Malaria vaccine development in Europe--preparing for the future. Vaccine 2015; 33:6137-44. [PMID: 26431986 DOI: 10.1016/j.vaccine.2015.09.074] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 09/03/2015] [Accepted: 09/22/2015] [Indexed: 10/23/2022]
Abstract
The deployment of a safe and effective malaria vaccine will be an important tool for the control of malaria and the reduction in malaria deaths. With the launch of the 2030 Malaria Vaccine Technology Roadmap, the malaria community has updated the goals and priorities for the development of such a vaccine and is now paving the way for a second phase of malaria vaccine development. During a workshop in Brussels in November 2014, hosted by the European Vaccine Initiative, key players from the European, North American and African malaria vaccine community discussed European strategies for future malaria vaccine development in the global context. The recommendations of the European malaria community should guide researchers, policy makers and funders of global health research and development in fulfilling the ambitious goals set in the updated Malaria Vaccine Technology Roadmap.
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Affiliation(s)
- Nicola K Viebig
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany.
| | - Flavia D'Alessio
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany
| | - Simon J Draper
- The Jenner Institute, University of Oxford , Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - B Kim Lee Sim
- Sanaria Inc., 9800 Medical Center Drive, Suite A209, Rockville, MD 20850, USA
| | - Benjamin Mordmüller
- Institut für Tropenmedizin, Universitätsklinikum Tübingen, Wilhelmstraße 27, 72074 Tübingen, Germany; Centre de Recherches Médicales de Lambaréné, B.P. 118 Lambaréné, Gabon
| | - Paul W Bowyer
- The National Institute for Biological Standards and Control (NIBSC), Blanche Lane, South Mimms, Potters Bar, Hertfordshire, EN6 3QG, UK
| | - Adrian J F Luty
- IRD MERIT UMR 216, 75006 Paris, France; COMUE Sorbonne Paris Cité, Université Paris Descartes, Faculté des Sciences Pharmaceutiques et Biologiques, 75270 Paris, France
| | - Stefan Jungbluth
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany
| | - Chetan E Chitnis
- Institut Pasteur, 25-28 Rue du Docteur Roux, 75015 Paris, France
| | - Adrian V S Hill
- The Jenner Institute, University of Oxford , Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Peter Kremsner
- Institut für Tropenmedizin, Universitätsklinikum Tübingen, Wilhelmstraße 27, 72074 Tübingen, Germany; Centre de Recherches Médicales de Lambaréné, B.P. 118 Lambaréné, Gabon
| | - Alister G Craig
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Clemens H M Kocken
- Biomedical Primate Research Centre, Department of Parasitology, Lange Kleiweg 161, 2288 GJ Rijswijk, The Netherlands
| | - Odile Leroy
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany
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28
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Dunachie S, Hill AVS, Fletcher HA. Profiling the host response to malaria vaccination and malaria challenge. Vaccine 2015; 33:5316-20. [PMID: 26256528 PMCID: PMC4582768 DOI: 10.1016/j.vaccine.2015.07.107] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 07/27/2015] [Accepted: 07/29/2015] [Indexed: 12/21/2022]
Abstract
A vaccine for malaria is urgently required. The RTS,S vaccine represents major progress, but is only partially effective. Development of the next generation of highly effective vaccines requires elucidation of the protective immune response. Immunity to malaria is known to be complex, and pattern-based approaches such as global gene expression profiling are ideal for understanding response to vaccination and protection against disease. The availability of experimental sporozoite challenge in humans to test candidate malaria vaccines offers a precious opportunity unavailable for other current targets of vaccine research such as HIV, tuberculosis and Ebola. However, a limited number of transcriptional profiling studies in the context of malaria vaccine research have been published to date. This review outlines the background, existing studies, limits and opportunities for gene expression studies to accelerate malaria vaccine research.
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Affiliation(s)
- Susanna Dunachie
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Churchill Hospital, Oxford OX3 7LJ, UK; Mahidol-Oxford Tropical Medicine Research Unit, 3rd Floor, 60th Anniversary Chalermprakiat Building, 420/6 Ratchawithi Road, Bangkok 10400, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford, Old Road Campus, Roosevelt Drive, Oxford OX3 7FZ, UK.
| | - Adrian V S Hill
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Churchill Hospital, Oxford OX3 7LJ, UK
| | - Helen A Fletcher
- London School of Hygiene & Tropical Medicine, London, W1CE 7HT, UK; The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Churchill Hospital, Oxford OX3 7LJ, UK
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29
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Roth JM, Korevaar DA, Leeflang MMG, Mens PF. Molecular malaria diagnostics: A systematic review and meta-analysis. Crit Rev Clin Lab Sci 2015; 53:87-105. [DOI: 10.3109/10408363.2015.1084991] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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30
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Siddiqui AJ, Bhardwaj J, Goyal M, Prakash K, Soni A, Tiwari V, Puri SK. Assessment of real-time method to detect liver parasite burden under different experimental conditions in mice infected with Plasmodium yoelii sporozoites. Microb Pathog 2015; 89:35-42. [PMID: 26341953 DOI: 10.1016/j.micpath.2015.08.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 08/19/2015] [Accepted: 08/24/2015] [Indexed: 10/23/2022]
Abstract
Use of highly specific, sensitive and quantitative Real-Time PCR (qRT-PCR) based methods greatly facilitate the monitoring of experimental drug intervention and vaccination efficacy targeting liver stage malaria parasite. Here, in this study we have used qRT-PCR to detect the growing liver stage parasites following inoculation of Plasmodium yoelii sporozoite. Route of sporozoite administration and size of the sporozoite inoculums are two major determinants that affect the liver stage parasite load and therefore its detection and quantification. Thus, these factors need to be addressed to determine the accuracy of detection and quantification of Real-Time PCR method. Furthermore, applicability of quantitative RT-PCR system needs to be confirmed by analyzing the effect of different antimalarials on liver stage parasite burden. We have observed that parasite burden in mice infected via intravenous route was higher compared to that in subcutaneous, intradermal and intraperitoneal route infected mice. Moreover, this method detected liver stage parasite load with as low as 50 sporozoites. The inhibition studies with primaquine and atovaquone revealed inhibition of liver stage parasite and well correlated with patency and course of blood stage infection. This study characterized the simplicity, accuracy, and quantitative analysis of liver stage parasite development by real time PCR under different experimental conditions. Use of real time PCR method greatly improves the reproducibility and applicability to estimate the efficacy and potency of vaccine or drug candidates targeting liver stage parasite.
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Affiliation(s)
- Arif Jamal Siddiqui
- Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow 226031, Uttar Pradesh, India; Academy of Scientific and Innovative Research, (AcSIR), Anusandhan Bhawan, New Delhi, India.
| | - Jyoti Bhardwaj
- Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow 226031, Uttar Pradesh, India; Academy of Scientific and Innovative Research, (AcSIR), Anusandhan Bhawan, New Delhi, India.
| | - Manish Goyal
- Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow 226031, Uttar Pradesh, India.
| | - Kirtika Prakash
- Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow 226031, Uttar Pradesh, India.
| | - Awakash Soni
- Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow 226031, Uttar Pradesh, India; Academy of Scientific and Innovative Research, (AcSIR), Anusandhan Bhawan, New Delhi, India.
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, Rajasthan, India.
| | - Sunil K Puri
- Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow 226031, Uttar Pradesh, India; Academy of Scientific and Innovative Research, (AcSIR), Anusandhan Bhawan, New Delhi, India.
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31
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Golassa L, Baliraine FN, Enweji N, Erko B, Swedberg G, Aseffa A. Microscopic and molecular evidence of the presence of asymptomatic Plasmodium falciparum and Plasmodium vivax infections in an area with low, seasonal and unstable malaria transmission in Ethiopia. BMC Infect Dis 2015; 15:310. [PMID: 26242405 PMCID: PMC4526179 DOI: 10.1186/s12879-015-1070-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 07/29/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The presence of asymptomatic infections has serious implications for malaria elimination campaigns. Since asymptomatic carriers do not seek treatment for their infection and may become gametocyte carriers, they undoubtedly contribute to the persistence of malaria transmission in a population. The presence of asymptomatic parasitemias was noted in areas with seasonal malaria transmission. In Ethiopia there is a paucity of data regarding the prevalence of asymptomatic malaria carriage. This study was undertaken to assess the presence and prevalence of asymptomatic Plasmodium falciparum and Plasmodium vivax infections in south-central Oromia, Ethiopia. METHODS A total of 1094 apparently healthy individuals ≥ 2 years of age in south-central Oromia, Ethiopia, an area with seasonal and unstable malaria transmission, were screened for the presence of asymptomatic plasmodial infections. Finger-prick blood samples were taken from each participant for blood film preparation for microscopy and the rapid diagnostic test (RDT). Blood samples were also spotted on Whatman 3MM filter paper for parasite DNA extraction. RESULTS The prevalence of asymptomatic Plasmodium carriage (P. falciparum, P. vivax and mixed species) was 5.0 % (55/1,094) as determined by microscopy, while the prevalence as determined using RDT was 8.2 % (90/1,094). PCR was done on 47 of 55 microscopy-confirmed and on 79 of 90 RDT-confirmed samples. PCR detected parasite DNA in 89.4 % (42/47) of the microscopy-positive samples and in 77.2 % (61/79) of the RDT-positive samples. No significant difference was observed in the prevalence of asymptomatic P. falciparum or P. vivax infections in the study area (P > 0.1). However, the prevalence of asymptomatic parasitaemia was significantly associated with gender (OR = 0.47, P = 0.015; being higher in males than females) and age (X(2) = 25, P < 0.001; being higher in younger than in older individuals). Age and parasite densities had an inverse relationship. CONCLUSIONS This study confirms the presence of asymptomatic P. falciparum and P. vivax infections in south-central Oromia, an area with low, seasonal and unstable malaria transmission in Ethiopia. Of 55 microscopically confirmed asymptomatic infections, P. falciparum monoinfection accounted for 45.5 % and of 90 RDT positive asymptomatic infections, 66.7 % were P. falciparum. Although not statistically significant, P. falciparum accounted for a relatively large number of the asymptomatic infections as determined by both tests. The prevalence of asymptomatic parasitaemia was highest in the younger age group. HRP-2-based RDTs specific for P. falciparum showed high false positivity rate compared to Plasmodium lactate dehydrogenase (pLDH) specific to P. vivax. Although microscopy and RDT detected substantial numbers of asymptomatic infections in apparently healthy inhabitants, the use of a highly sensitive molecular diagnostics offers a more accurate assessment of the magnitude of asymptomatic infections.
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Affiliation(s)
- Lemu Golassa
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia. .,Armauer Hansen Research Institute, Addis Ababa, Ethiopia.
| | | | - Nizar Enweji
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
| | - Berhanu Erko
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Göte Swedberg
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
| | - Abraham Aseffa
- Armauer Hansen Research Institute, Addis Ababa, Ethiopia.
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