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Kim J, Lim DH, Mihn DC, Nam J, Jang WS, Lim CS. Clinical Usefulness of LabChip Real-time PCR using Lab-On-a-Chip Technology for Diagnosing Malaria. THE KOREAN JOURNAL OF PARASITOLOGY 2021; 59:77-82. [PMID: 33684990 PMCID: PMC7939964 DOI: 10.3347/kjp.2021.59.1.77] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 11/30/2020] [Accepted: 12/06/2020] [Indexed: 12/29/2022]
Abstract
As malaria remains a major health problem worldwide, various diagnostic tests have been developed, including microscopy-based and rapid diagnostic tests. LabChip real-time PCR (LRP) is a small and portable device used to diagnose malaria using lab-on-a-chip technology. This study aimed to evaluate the diagnostic performance of LRP for detecting malaria parasites. Two hundred thirteen patients and 150 healthy individuals were enrolled from May 2009 to October 2015. A diagnostic detectability of LRP for malaria parasites was compared to that of conventional RT-PCR. Sensitivity of LRP for Plasmodium vivax, P. falciparum, P. malariae, and P. ovale was 95.5%, 96.0%, 100%, and 100%, respectively. Specificity of LRP for P. vivax, P. falciparum, P. malariae, and P. ovale was 100%, 99.3%, 100%, and 100%, respectively. Cohen's Kappa coefficients between LRP and CFX96 for detecting P. vivax, P. falciparum, P. malariae, and P. ovale were 0.96, 0.98, 1.00, and 1.00, respectively. Significant difference was not observed between the results of LRP and conventional RT-PCR and microscopic examination. A time required to amplify DNAs using LRP and conventional RT-PCR was 27 min and 86 min, respectively. LRP amplified DNAs 2 times more fast than conventional RT-PCR due to the faster heat transfer. Therefore, LRP could be employed as a useful tool for detecting malaria parasites in clinical laboratories.
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Affiliation(s)
- Jeeyong Kim
- Department of Laboratory Medicine, Korea University College of Medicine, Seoul 08308, Korea
| | - Da Hye Lim
- Department of Laboratory Medicine, Korea University College of Medicine, Seoul 08308, Korea
| | - Do-CiC Mihn
- Department of Diagnostic Immunology, Seegene Medical Foundation, Seoul 04805, Korea
| | - Jeonghun Nam
- Department of Laboratory Medicine, Korea University College of Medicine, Seoul 08308, Korea
| | - Woong Sik Jang
- Department of Laboratory Medicine, Korea University College of Medicine, Seoul 08308, Korea
| | - Chae Seung Lim
- Department of Laboratory Medicine, Korea University College of Medicine, Seoul 08308, Korea
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2
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A Comparison Between Manual Count, Flow Cytometry and Quantitative Real-Time Polymerase Chain Reaction as a Means of Determining Babesia rossi Parasitaemia in Naturally Infected Dogs. Acta Parasitol 2020; 65:128-135. [PMID: 31721056 DOI: 10.2478/s11686-019-00134-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 10/03/2019] [Indexed: 11/20/2022]
Abstract
PURPOSE Light microscopic manual count is the current gold standard for parasite quantification. The ability to determine parasite density in whole blood is crucial to understanding disease pathogenesis and finding a suitable automated method of Babesia rossi parasite quantification would facilitate higher throughput and provide results that are more objective. This study investigated both peripheral capillary and central venous whole blood to estimate the correlations between light microscopy, flow cytometry and quantitative real-time polymerase chain reaction (qPCR). METHODS Peripheral capillary and central venous blood were sampled from 40 naturally B. rossi-infected dogs and 10 healthy control dogs. Samples were analysed by reverse line blot hybridization assay to confirm a mono-B. rossi infection. Capillary blood parasite density was detected using light microscopic manual counting and venous blood parasitaemia detected by manual counts, flow cytometry and qPCR. RESULTS A significant correlation was found between the venous manual counts and flow cytometry (rs = 0.465; P < 0.001), as well as qPCR (rs = - 0.500; P < 0.001). A significant correlation was also observed between the capillary manual counts compared to venous manual counts (rs = 0.793; P < 0.001), flow cytometry (rs = 0.399; P = 0.004), and qPCR (rs = - 0.526; P < 0.001). CONCLUSIONS The study results suggest that qPCR is of value as an alternative to the gold standard manual count for detecting B. rossi parasitaemia in canine whole blood and that flow cytometry may be useful with further refinement of issues such as background fluorescence and the influence of reticulocytes.
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Genome Mining-Based Identification of Identical Multirepeat Sequences in Plasmodium falciparum Genome for Highly Sensitive Real-Time Quantitative PCR Assay and Its Application in Malaria Diagnosis. J Mol Diagn 2019; 21:824-838. [PMID: 31158524 DOI: 10.1016/j.jmoldx.2019.04.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 04/02/2019] [Accepted: 04/30/2019] [Indexed: 11/21/2022] Open
Abstract
Developing ultrasensitive methods capable of detecting submicroscopic parasitemia-a challenge that persists in low transmission areas, asymptomatic carriers, and patients showing recrudescence-is vital to achieving malaria eradication. Nucleic acid amplification techniques offer improved analytical sensitivity but are limited by the number of copies of the amplification targets. Herein, we perform a novel genome mining approach to identify a pair of identical multirepeat sequences (IMRSs) that constitute 170 and 123 copies in the Plasmodium falciparum genome and explore their potential as primers for PCR. Real-time quantitative PCR analyses have shown the ability of P. falciparum IMRSs to amplify as low as 2.54 fg of P. falciparum genomic DNA (approximately 0.1 parasite), with a striking 100-fold increase in detection limit when compared with P. falciparum 18S rRNA (251.4 fg; approximately 10 parasites). Validation with clinical samples from malaria-endemic regions has shown 6.70 ± 1.66 cycle better detection threshold in terms of Ct value for P. falciparum IMRSs, with approximately 100% sensitivity and specificity. Plasmodium falciparum IMRS assays are also capable of detecting submicroscopic infections in asymptomatic samples. To summarize, this approach of initiating amplification at multiple loci across the genome and generating more products with increased analytical sensitivity is different from classic approaches amplifying multicopy genes or tandem repeats. This can serve as a platform technology to develop advanced diagnostics for various pathogens.
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Yin J, Li M, Yan H, Zhou S. Considerations on PCR-based methods for malaria diagnosis in China malaria diagnosis reference laboratory network. Biosci Trends 2019; 12:510-514. [PMID: 30473560 DOI: 10.5582/bst.2018.01198] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Precise diagnosis is a key measurement for malaria control and elimination, traditional microscopy and rapid diagnostic tests cannot satisfy the requirements especially in the low transmission endemic areas or in the malaria elimination phase. Polymerase chain reaction (PCR) with high sensitivity and specificity can be considered as a diagnostic standard while no uniform PCR assay was established due to variations in their performance and lack of formal external quality assurance programs for validation for PCR assays in use. Here, 24 articles including 43 paired comparative evaluations limited to paired comparison of diagnostic performance between real-time PCR and conventional PCR to detect plasmodium in blood samples of human subjects from clinics or the field are systematically summarized. And according to the Landis and Koch classification, nineteen pairs showed almost perfect agreement, followed by 8 pairs of moderate agreement and 4 pairs of good agreement, while the kappa values of 12 pairs couldn't be examined. Moreover, the performance of 14 pairs were completely the same and 8 pairs had no differences, but 14 pairs were significant different including 8 pairs of real-time PCR with better performance than conventional PCR. Therefore, it is still an outstanding issue to choose PCR methods, and more work such as the standardization of materials and methods in use and their availability are needed to settle priority to better promote the role of malaria diagnosis reference laboratories.
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Affiliation(s)
- Jianhai Yin
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Diseases Research, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasite and Vector Biology, Ministry of Health
| | - Mei Li
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Diseases Research, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasite and Vector Biology, Ministry of Health
| | - He Yan
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Diseases Research, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasite and Vector Biology, Ministry of Health
| | - Shuisen Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Diseases Research, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasite and Vector Biology, Ministry of Health
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Almeida-de-Oliveira NK, Moreira OC, de Lavigne AR, Mendonça-Lima L, Werneck GL, Daniel-Ribeiro CT, Ferreira-da-Cruz MDF. Analytical validation of real-time quantitative PCR assays for optimum diagnosis of vivax malaria. Mem Inst Oswaldo Cruz 2019; 114:e180350. [PMID: 30726341 PMCID: PMC6358008 DOI: 10.1590/0074-02760180350] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 12/26/2018] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND The prompt diagnosis of plasmodial species for effective treatment prevents
worsening of individual health and avoids transmission maintenance or even
malaria reintroduction in areas where Plasmodium does not
exist. Polymerase chain reaction (PCR) allows for the detection of parasites
below the threshold of microscopic examination. OBJECTIVE Our aim was to develop a real-time PCR test to reduce diagnostic errors and
increase efficacy. METHODS The lower limit of quantification and the linearity/analytical sensitivity
to measure sensitivity or limit of detection (LoD) were determined.
Intra-assay variations (repeatability) and alterations between assays,
operators, and instruments (reproducibility) were also assessed to set
precision. FINDINGS The linearity in SYBR™ Green and TaqMan™ systems was 106 and
102 copies and analytical sensitivity 1.13 and 1.17
copies/μL, respectively. Real-time PCR was more sensitive than conventional
PCR, showing a LoD of 0.01 parasite (p)/μL. Reproducibility and
repeatability (precision) were 100% for up to 0.1 p/μL in SYBR™ Green and 1
p/μL in TaqMan™ and conventional PCR. CONCLUSION Real-time PCR may replace conventional PCR in reference laboratories for
P. vivax detection due to its rapidity. The TaqMan™
system is the most indicated when quantification assays are required.
Performing tests in triplicate when diagnosing
Plasmodium-infected-asymptomatic individuals is recommended
to minimise diagnostic errors.
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Affiliation(s)
| | - Otacílio C Moreira
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Biologia Molecular e Doenças Endêmicas, Rio de Janeiro, RJ, Brasil
| | - Aline Rosa de Lavigne
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Pesquisa em Malária, Rio de Janeiro, RJ, Brasil
| | - Leila Mendonça-Lima
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Genômica Funcional e Bioinformática, Rio de Janeiro, RJ, Brasil
| | - Guilherme Loureiro Werneck
- Universidade do Estado do Rio de Janeiro, Instituto de Medicina Social, Departamento de Epidemiologia, Rio de Janeiro, RJ, Brasil
| | - Cláudio Tadeu Daniel-Ribeiro
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Pesquisa em Malária, Rio de Janeiro, RJ, Brasil
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Kitutu FE, Wamani H, Selling KE, Katabazi FA, Kuteesa RB, Peterson S, Kalyango JN, Mårtensson A. Can malaria rapid diagnostic tests by drug sellers under field conditions classify children 5 years old or less with or without Plasmodium falciparum malaria? Comparison with nested PCR analysis. Malar J 2018; 17:365. [PMID: 30326926 PMCID: PMC6192306 DOI: 10.1186/s12936-018-2508-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 10/06/2018] [Indexed: 01/02/2023] Open
Abstract
Background Malaria rapid diagnostic tests (RDTs) available as dipsticks or strips, are simple to perform, easily interpretable and do not require electricity nor infrastructural investment. Correct interpretation of and compliance with the RDT results is a challenge to drug sellers. Thus, drug seller interpretation of RDT strips was compared with laboratory scientist re-reading, and PCR analysis of Plasmodium DNA extracted from RDT nitrocellulose strips and fast transient analysis (FTA) cards. Malaria RDT cassettes were also assessed as a potential source of Plasmodium DNA. Methods A total of 212 children aged between 2 and 60 months, 199 of whom had complete records at two study drug shops in south western Uganda participated in the study. Duplicate 5 μL samples of capillary blood were picked from the 212 children, dispensed onto the sample well of the CareStart™ Pf-HRP2 RDT cassette and a FTA, Whatman™ 3MM filter paper in parallel. The RDT strip was interpreted by the drug seller within 15–20 min, visually re-read centrally by laboratory scientist and from it; Plasmodium DNA was recovered and detected by PCR, and compared with FTA recovered P. falciparum DNA PCR detection. Results Malaria positive samples were 62/199 (31.2%, 95% CI 24.9, 38.3) by drug seller interpretation of RDT strip, 59/212 (27.8%, 95% CI 22.2, 34.3) by laboratory scientist, 55/212 (25.9%, 95% CI 20.0, 32.6) by RDT nitrocellulose strip PCR and 64/212 (30.2%, 95% CI 24.4, 37.7). The overall agreement between the drug seller interpretation and laboratory scientist re-reading of the RDT strip was 93.0% with kappa value of 0.84 (95% CI 0.75, 0.92). The drug seller compliance with the reported RDT results was 92.5%. The performance of the three diagnostic strategies compared with FTA-PCR as the gold standard had sensitivity between 76.6 and 86.9%, specificity above 90%, positive predictive values ranging from 79.0 to 89.8% and negative predictive values above 90%. Conclusion Drug sellers can use RDTs in field conditions and achieve acceptable accuracy for malaria diagnosis, and they comply with the RDT results. Plasmodium DNA can be recovered from RDT nitrocellulose strips even in the context of drug shops. Future malaria surveillance and diagnostic quality control studies with RDT cassette as a source of Plasmodium DNA are recommended. Electronic supplementary material The online version of this article (10.1186/s12936-018-2508-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Freddy Eric Kitutu
- Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Uppsala, Sweden. .,Pharmacy Department, Makerere University College of Health Sciences, Kampala, Uganda.
| | - Henry Wamani
- School of Public Health, Makerere University College of Health Sciences, Kampala, Uganda
| | - Katarina Ekholm Selling
- Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Uppsala, Sweden
| | - Fred Ashaba Katabazi
- Department of Medical Microbiology, Makerere University College of Health Sciences, Kampala, Uganda
| | - Ronald Bisaso Kuteesa
- Infectious Disease Institute, Makerere University College of Health Sciences, Kampala, Uganda
| | - Stefan Peterson
- Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Uppsala, Sweden.,School of Public Health, Makerere University College of Health Sciences, Kampala, Uganda.,UNICEF, Health Section, 3 UN Plaza, New York, NY, 10017, USA
| | - Joan Nakayaga Kalyango
- Pharmacy Department, Makerere University College of Health Sciences, Kampala, Uganda.,Clinical Epidemiology and Biostatistics Unit, Makerere University College of Health Sciences, Kampala, Uganda
| | - Andreas Mårtensson
- Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Uppsala, Sweden
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Björkman A, Cook J, Sturrock H, Msellem M, Ali A, Xu W, Molteni F, Gosling R, Drakeley C, Mårtensson A. Spatial Distribution of Falciparum Malaria Infections in Zanzibar: Implications for Focal Drug Administration Strategies Targeting Asymptomatic Parasite Carriers. Clin Infect Dis 2018; 64:1236-1243. [PMID: 28431115 PMCID: PMC5399945 DOI: 10.1093/cid/cix136] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Indexed: 12/30/2022] Open
Abstract
Background. Optimal use of mass/targeted screen-and-treat or mass or focal drug administration as malaria elimination strategies remains unclear. We therefore studied spatial distribution of Plasmodium falciparum infections to compare simulated effects of these strategies on reducing the parasite reservoir in a pre-elimination setting. Methods. P. falciparum rapid diagnostic tests (RDTs) and molecular (polymerase chain reaction [PCR]) and serological (enzyme-linked immunosorbent assay) analyses were performed on finger-prick blood samples from a population-based survey in 3 adjacent communities. Results. Among 5278 persons screened, 13 (0.2%) were positive by RDT and 123 (2.3%) by PCR. PCR-positive individuals were scattered over the study area, but logistic regression analysis suggested a propensity of these infections to cluster around RDT-positive individuals. The odds ratios for being PCR positive was 7.4 (95% confidence interval, 2.8–19.9) for those living in the household of an RDT-positive individual and 1.64 (1.0–2.8; P = .06) for those living within <300 m, compared with >1000 m. Treating everyone within households of RDT-positive individuals (1% population) would target 13% of those who are PCR positive. Treating all living within a radius of <300 or <1000 m (14% or 58% population) would target 30% or 66% of infections, respectively. Among 4431 serologically screened individuals, 26% were seropositive. Treating everyone within seropositive households (63% population) would target 77% of PCR-positive individuals. Conclusions. Presumptive malaria treatment seemed justified within RDT-positive households and potentially worth considering within, for example, a radius of <300 m. Serology was not discriminative enough in identifying ongoing infections for improving focal interventions in this setting but may rather be useful to detect larger transmission foci.
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Affiliation(s)
- Anders Björkman
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Jackie Cook
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.,MRC Tropical Epidemiology Group, Faculty of Epidemiology and Population Health
| | - Hugh Sturrock
- Global Health Group, University of California, San Francisco, CA, USA
| | - Mwinyi Msellem
- Zanzibar Malaria Elimination Programme, Zanzibar Ministry of Health, Stone Town, Zanzibar, United Republic of Tanzania
| | - Abdullah Ali
- Zanzibar Malaria Elimination Programme, Zanzibar Ministry of Health, Stone Town, Zanzibar, United Republic of Tanzania
| | - Weiping Xu
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Fabrizio Molteni
- Swiss Tropical and Public Health Institute, Dar es Salaam, Tanzania
| | - Roly Gosling
- Global Health Group, University of California, San Francisco, CA, USA
| | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Andreas Mårtensson
- Department of Women's and Children's Health, International Maternal and Child Health, Uppsala University, Sweden
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Chen C, Ye S, Hu H, Xue C, Yu X. Use of electrical penetration graphs (EPG) and quantitative PCR to evaluate the relationship between feeding behaviour and Pandora neoaphidis infection levels in green peach aphid, Myzus persicae. JOURNAL OF INSECT PHYSIOLOGY 2018; 104:9-14. [PMID: 29133229 DOI: 10.1016/j.jinsphys.2017.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 11/08/2017] [Accepted: 11/09/2017] [Indexed: 06/07/2023]
Abstract
A real-time qPCR method was developed, validated, and used to quantity the fungal pathogen, P. neoaphidis, within aphids at different times during infection; colonization rate fitted the Gompertz model well (R2 = 0.9356). Feeding behaviour of P. neoaphidis-infected and uninfected M. persicae were investigated, for the first time, using DC-electrical penetration graphs (DC-EPG) that characterized the waveforms made during different aphid stylet probing periods corresponding to epidermis penetration, salivation and ingestion. In the 6 h following the 12-h incubation period (to achieve infection), there were significant differences in the number of events of Np (non-probing) and C (stylet pathway) between infected and uninfected aphids. However, the difference between total duration of Np and C were not significantly different between infected and uninfected aphids. There were no significant differences in the number of events or total duration of E1 (phloem salivation) or E2 (phloem ingestion) between infected and uninfected aphids. There were significant differences in mean number of events and total duration of the pd waveform (intracellular punctures) in infected and uninfected aphids. In the 16 h prior to death, the same differences in behaviour were observed but they were even more obvious. Furthermore, the total duration time of E2 was significantly greater in uninfected aphids than infected aphids, a change that had not been observed in the first 6 h observation period. In conclusion, qPCR quantification demonstrated 'molecular' colonization levels throughout infection, and EPG data analysis during the two periods (during early infection and then during late infection just prior to death) demonstrated the actual physical effects of fungal infection on feeding behaviour of M. persicae; this has the potential to decrease the aphid's capacity of transmission and dispersal. These studies increase our understanding of the interaction between P. neoaphidis and its host aphid.
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Affiliation(s)
- Chun Chen
- China Jiliang University, Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, Hangzhou 310018, China.
| | - Sudan Ye
- Zhejiang Economic & Trade Polytechnic, Hangzhou 310018, China
| | - Huajun Hu
- China Jiliang University, Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, Hangzhou 310018, China
| | - Chengmei Xue
- China Jiliang University, Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, Hangzhou 310018, China
| | - Xiaoping Yu
- China Jiliang University, Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, Hangzhou 310018, China
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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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10
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Hofmann N, Mwingira F, Shekalaghe S, Robinson LJ, Mueller I, Felger I. Ultra-sensitive detection of Plasmodium falciparum by amplification of multi-copy subtelomeric targets. PLoS Med 2015; 12:e1001788. [PMID: 25734259 PMCID: PMC4348198 DOI: 10.1371/journal.pmed.1001788] [Citation(s) in RCA: 239] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 01/08/2015] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Planning and evaluating malaria control strategies relies on accurate definition of parasite prevalence in the population. A large proportion of asymptomatic parasite infections can only be identified by surveillance with molecular methods, yet these infections also contribute to onward transmission to mosquitoes. The sensitivity of molecular detection by PCR is limited by the abundance of the target sequence in a DNA sample; thus, detection becomes imperfect at low densities. We aimed to increase PCR diagnostic sensitivity by targeting multi-copy genomic sequences for reliable detection of low-density infections, and investigated the impact of these PCR assays on community prevalence data. METHODS AND FINDINGS Two quantitative PCR (qPCR) assays were developed for ultra-sensitive detection of Plasmodium falciparum, targeting the high-copy telomere-associated repetitive element 2 (TARE-2, ∼250 copies/genome) and the var gene acidic terminal sequence (varATS, 59 copies/genome). Our assays reached a limit of detection of 0.03 to 0.15 parasites/μl blood and were 10× more sensitive than standard 18S rRNA qPCR. In a population cross-sectional study in Tanzania, 295/498 samples tested positive using ultra-sensitive assays. Light microscopy missed 169 infections (57%). 18S rRNA qPCR failed to identify 48 infections (16%), of which 40% carried gametocytes detected by pfs25 quantitative reverse-transcription PCR. To judge the suitability of the TARE-2 and varATS assays for high-throughput screens, their performance was tested on sample pools. Both ultra-sensitive assays correctly detected all pools containing one low-density P. falciparum-positive sample, which went undetected by 18S rRNA qPCR, among nine negatives. TARE-2 and varATS qPCRs improve estimates of prevalence rates, yet other infections might still remain undetected when absent in the limited blood volume sampled. CONCLUSIONS Measured malaria prevalence in communities is largely determined by the sensitivity of the diagnostic tool used. Even when applying standard molecular diagnostics, prevalence in our study population was underestimated by 8% compared to the new assays. Our findings highlight the need for highly sensitive tools such as TARE-2 and varATS qPCR in community surveillance and for monitoring interventions to better describe malaria epidemiology and inform malaria elimination efforts.
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Affiliation(s)
- Natalie Hofmann
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Felista Mwingira
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- Biological Sciences Department, Dar es Salaam University College of Education, Dar es Salaam, Tanzania
| | | | - Leanne J. Robinson
- Papua New Guinea Institute of Medical Research, Madang and Maprik, Papua New Guinea
- Walter and Eliza Hall Institute, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Ivo Mueller
- Walter and Eliza Hall Institute, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
- Centre de Recerca en Salut Internacional de Barcelona, Barcelona, Spain
| | - Ingrid Felger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail:
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11
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Kim JY, Goo YK, Ji SY, Shin HI, Han ET, Hong Y, Chung DI, Cho SH, Lee WJ. Development and efficacy of real-time PCR in the diagnosis of vivax malaria using field samples in the Republic of Korea. PLoS One 2014; 9:e105871. [PMID: 25148038 PMCID: PMC4141806 DOI: 10.1371/journal.pone.0105871] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 07/25/2014] [Indexed: 11/18/2022] Open
Abstract
The development of sensitive, rapid, and accurate diagnostic methods for vivax malaria is essential for the effective control of malaria in the Republic of Korea, where vivax malaria patients usually show low parasitemia. In this study, a TaqMan-based real-time polymerase chain reaction (PCR) method was established and compared with other PCR-based assays, including nested PCR, loop-mediated isothermal amplification, and multiplex PCR, using samples from febrile patients with suspected vivax malaria. The established real-time PCR had a high sensitivity (99.6%) and specificity (100%). Therefore, this sensitive, specific, rapid, and quantitative real-time PCR method could be used for the routine diagnosis of vivax malaria in the laboratory of the Korea National Institute of Health.
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Affiliation(s)
- Jung-Yeon Kim
- Division of Malaria and Parasitic Diseases, National Institute of Health, Korea CDC, Osong Saeng-myeong 2 ro, Osong Health Technology Administration Complex 187, Osong, Republic of Korea
| | - Youn-Kyoung Goo
- Division of Malaria and Parasitic Diseases, National Institute of Health, Korea CDC, Osong Saeng-myeong 2 ro, Osong Health Technology Administration Complex 187, Osong, Republic of Korea
- Department of Parasitology and Tropical Medicine, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - So-Young Ji
- Division of Malaria and Parasitic Diseases, National Institute of Health, Korea CDC, Osong Saeng-myeong 2 ro, Osong Health Technology Administration Complex 187, Osong, Republic of Korea
| | - Hyun-Il Shin
- Division of Malaria and Parasitic Diseases, National Institute of Health, Korea CDC, Osong Saeng-myeong 2 ro, Osong Health Technology Administration Complex 187, Osong, Republic of Korea
| | - Eun-Taek Han
- Department of Parasitology, Kangwon National University College of Medicine, Chuncheon, Republic of Korea
| | - Yeonchul Hong
- Department of Parasitology and Tropical Medicine, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Dong-Il Chung
- Department of Parasitology and Tropical Medicine, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Shin-Hyung Cho
- Division of Malaria and Parasitic Diseases, National Institute of Health, Korea CDC, Osong Saeng-myeong 2 ro, Osong Health Technology Administration Complex 187, Osong, Republic of Korea
| | - Won-Ja Lee
- Division of Malaria and Parasitic Diseases, National Institute of Health, Korea CDC, Osong Saeng-myeong 2 ro, Osong Health Technology Administration Complex 187, Osong, Republic of Korea
- * E-mail:
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12
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Lei W, Li S, Peng Q, Zhang G, Liu X. A real-time qPCR assay to quantify Ophiocordyceps sinensis biomass in Thitarodes larvae. J Microbiol 2013; 51:229-33. [PMID: 23625225 DOI: 10.1007/s12275-013-2241-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 12/21/2012] [Indexed: 12/01/2022]
Abstract
Ophiocordyceps sinensis, an entomogenous fungus parasitic in the larvae of moths (Lepidoptera), is one of the most valuable medicinal fungi, and it only distributed naturally on the Tibetan Plateau. The parasitical amount of O. sinensis in various tissues of the host Thitarodes larvae has an important role in study the occurrence and developmental mechanisms of O. sinensis, but there no an effective method to detect the fungal anamorph. A real-time quantitative PCR (qPCR) system, including a pair of species-specific ITS primers and its related program, was developed for O. sinensis assay with high reliability and efficiency. A calibration curve was established and exhibited a very good linear correlation between the fungal biomass and the C T values (R (2)=0.999419) by the qPCR system. Based on this method, O. sinensis was detected rapidly in four tissues of its host caterpillars, and the results were shown as following: the maximum content of O. sinensis parasitized in the fat-body, and next came body-wall; both of them were much larger than that observed in the haemolymph and intestinal-wall. Taken together, these results show that qPCR assays may become useful tools for study on developmental mechanism of O. sinensis.
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Affiliation(s)
- Wei Lei
- Food and Health Engineering Research Center of State Education Ministry, School of Life Sciences, Sun Yat-sen University, Guangzhou, P. R. China
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13
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Yan J, Li N, Wei X, Li P, Zhao Z, Wang L, Li S, Li X, Wang Y, Li S, Yang Z, Zheng B, Zhou G, Yan G, Cui L, Cao Y, Fan Q. Performance of two rapid diagnostic tests for malaria diagnosis at the China-Myanmar border area. Malar J 2013; 12:73. [PMID: 23433230 PMCID: PMC3599043 DOI: 10.1186/1475-2875-12-73] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 02/18/2013] [Indexed: 12/02/2022] Open
Abstract
Background Rapid diagnostic tests (RDTs) have become an essential tool in the contemporary malaria control and management programmes in the world. This study aims to evaluate the performance of two commonly used RDTs for malaria diagnosis in the China-Myanmar border area. Methods A total 606 febrile patients in the China-Myanmar border were recruited to this study and were diagnosed for malaria infections by microscopy, two RDTs tests (Pf/Pan device, and Pv/Pf device) and nested PCR. Results Malaria parasites were found in 143 patients by microscopy, of which 51, 73, and 19 were Plasmodium falciparum, Plasmodium vivax and P. falciparum/P. vivax mixed infections, respectively. Compared to microscopy, the sensitivity of the Pf/Pan device was 88.6% for P. falciparum and 69.9% for P. vivax with the specificity of 90.4%. For a subset of 350 patients, the sensitivity of the Pf/Pan device and Pv/Pf device for detection of P. falciparum was 87.5% and 91.7%, respectively; and for detection of P. vivax was 72.0% and 73.8%, respectively. The specificity of the Pf/Pan device and Pv/Pf device was 94.3% and 96.5%, respectively. Nested PCR detected malaria parasites in 174 of 606 samples, of which 67, 79, two and 26 were P. falciparum, P. vivax, P. ovale and P. falciparum/P. vivax mixed infections, respectively. Compared to nested PCR, all other methods had sensitivity below 80%, suggesting that a significant number of cases were missed. Conclusions Compared to PCR, both microscopy and RDTs had lower sensitivities. RDTs had similar performance to microscopy for P. falciparum diagnosis, but performed worse for P. vivax diagnosis. Other RDT products should be selected with higher sensitivity (and good specificity) for both P. falciparum and P. vivax diagnosis.
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Affiliation(s)
- Juan Yan
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China
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14
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Brown T, Smith LS, Oo EKS, Shawng K, Lee TJ, Sullivan D, Beyrer C, Richards AK. Molecular surveillance for drug-resistant Plasmodium falciparum in clinical and subclinical populations from three border regions of Burma/Myanmar: cross-sectional data and a systematic review of resistance studies. Malar J 2012; 11:333. [PMID: 22992214 PMCID: PMC3518194 DOI: 10.1186/1475-2875-11-333] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 08/15/2012] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Confirmation of artemisinin-delayed parasite clearance in Plasmodium falciparum along the Thai-Myanmar border has inspired a global response to contain and monitor drug resistance to avert the disastrous consequences of a potential spread to Africa. However, resistance data from Myanmar are sparse, particularly from high-risk areas where limited health services and decades of displacement create conditions for resistance to spread. Subclinical infections may represent an important reservoir for resistance genes that confer a fitness disadvantage relative to wild-type alleles. This study estimates the prevalence of resistance genotypes in three previously unstudied remote populations in Myanmar and tests the a priori hypothesis that resistance gene prevalence would be higher among isolates collected from subclinical infections than isolates collected from febrile clinical patients. A systematic review of resistance studies is provided for context. METHODS Community health workers in Karen and Kachin States and an area spanning the Indo-Myanmar border collected dried blood spots from 988 febrile clinical patients and 4,591 villagers with subclinical infection participating in routine prevalence surveys. Samples positive for P. falciparum 18 s ribosomal RNA by real-time PCR were genotyped for P. falciparum multidrug resistance protein (pfmdr1) copy number and the pfcrt K76T polymorphism using multiplex real-time PCR. RESULTS Pfmdr1 copy number increase and the pfcrt K76 polymorphism were determined for 173 and 269 isolates, respectively. Mean pfmdr1 copy number was 1.2 (range: 0.7 to 3.7). Pfmdr1 copy number increase was present in 17.5%, 9.6% and 11.1% of isolates from Karen and Kachin States and the Indo-Myanmar border, respectively. Pfmdr1 amplification was more prevalent in subclinical isolates (20.3%) than clinical isolates (6.4%, odds ratio 3.7, 95% confidence interval 1.1 - 12.5). Pfcrt K76T prevalence ranged from 90-100%. CONCLUSIONS Community health workers can contribute to molecular surveillance of drug resistance in remote areas of Myanmar. Marginal and displaced populations under-represented among previous resistance investigations can and should be included in resistance surveillance efforts, particularly once genetic markers of artemisinin-delayed parasite clearance are identified. Subclinical infections may contribute to the epidemiology of drug resistance, but determination of gene amplification from desiccated filter samples requires further validation when DNA concentration is low.
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Affiliation(s)
- Tyler Brown
- Johns Hopkins University School of Medicine, Broadway Research Building, 733 N. Broadway, Suite 147, Baltimore, MD, 21205, USA
- Global Health Access Program, 2550 Ninth Street, Ste 111, Berkeley, CA, 94710, USA
| | - Linda S Smith
- Global Health Access Program, 2550 Ninth Street, Ste 111, Berkeley, CA, 94710, USA
| | - Eh Kalu Shwe Oo
- Karen Department of Health and Welfare, PO Box 189, Mae Sot, Tak, 63110, Thailand
| | - Kum Shawng
- Office of the Director of the Health Department, Kachin Baptist Convention 135/Shan Su (South), Myitkyina, Kachin State, Myanmar
| | - Thomas J Lee
- Global Health Access Program, 2550 Ninth Street, Ste 111, Berkeley, CA, 94710, USA
- School of Medicine, University of California at Los Angeles, 924 Westwood Blvd, Suite 300, Los Angeles, CA, 90024, USA
| | - David Sullivan
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health 615 North Wolfe St, Room E5628, Baltimore, MD, 21205, USA
| | - Chris Beyrer
- Department of Epidemiology Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St., Suite E7152, Baltimore, MD, 21205, USA
| | - Adam K Richards
- Global Health Access Program, 2550 Ninth Street, Ste 111, Berkeley, CA, 94710, USA
- Department of General Internal Medicine and Health Services Research, University of California at Los Angeles, 911 Broxton Ave, Los Angeles, CA, 90025, USA
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Sanpool O, Intapan PM, Thanchomnang T, Janwan P, Lulitanond V, Doanh PN, Van Hien H, Dung DT, Maleewong W, Nawa Y. Rapid detection and differentiation of Clonorchis sinensis and Opisthorchis viverrini eggs in human fecal samples using a duplex real-time fluorescence resonance energy transfer PCR and melting curve analysis. Parasitol Res 2012; 111:89-96. [PMID: 22246366 DOI: 10.1007/s00436-011-2804-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 12/21/2011] [Indexed: 12/27/2022]
Abstract
We developed a single step duplex real-time fluorescence resonance energy transfer (FRET) PCR merged with melting curve analysis for the fast detection and differentiation of Clonorchis sinensis and Opisthorchis viverrini eggs in human fecal samples. Two species of mitochondrial NADH dehydrogenase subunit 2 (nad2) DNA elements, the 165-bp nad2 product of C. sinensis and the 209-bp nad2 product of O. viverrini, were amplified by species-specific primers, and the fluorescence melting curve analyses were generated from hybrid of amplicons and two pairs of species-specific fluorophore-labeled probes. By their different fluorescence channels and melting temperatures, both C. sinensis and O. viverrini eggs in infected human fecal samples were detected and differentiated with high (100%) sensitivity and specificity. Detection limit was as little as a single C. sinensis egg and two O. viverrini eggs in 100 mg of fecal sample. The assay could distinguish the DNA of both parasites from the DNA of negative fecal samples and fecal samples with other parasitosis, as well as from the well-defined genomic DNA of human leukocytes and other parasites. It can reduce labor time of microscopic examination and is not prone to carry over contamination of agarose electrophoresis. Our duplex real-time FRET PCR method would be useful to determine the accurate range of endemic areas and/or to discover the co-endemic areas of two liver flukes, C. sinensis and O. viverrini, in Asia. This method also would be helpful for the differential diagnosis of the suspected cases of liver fluke infections among travelers who had visited the endemic countries of those parasites.
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Affiliation(s)
- Oranuch Sanpool
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
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