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Kearney EA, Amratia P, Kang SY, Agius PA, Alene KA, O’Flaherty K, Oo WH, Cutts JC, Htike W, Da Silva Goncalves D, Razook Z, Barry AE, Drew D, Thi A, Aung KZ, Thu HK, Thein MM, Zaw NN, Htay WYM, Soe AP, Beeson JG, Simpson JA, Gething PW, Cameron E, Fowkes FJI. Geospatial joint modeling of vector and parasite serology to microstratify malaria transmission. Proc Natl Acad Sci U S A 2024; 121:e2320898121. [PMID: 38833464 PMCID: PMC11181033 DOI: 10.1073/pnas.2320898121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 04/30/2024] [Indexed: 06/06/2024] Open
Abstract
The World Health Organization identifies a strong surveillance system for malaria and its mosquito vector as an essential pillar of the malaria elimination agenda. Anopheles salivary antibodies are emerging biomarkers of exposure to mosquito bites that potentially overcome sensitivity and logistical constraints of traditional entomological surveys. Using samples collected by a village health volunteer network in 104 villages in Southeast Myanmar during routine surveillance, the present study employs a Bayesian geostatistical modeling framework, incorporating climatic and environmental variables together with Anopheles salivary antigen serology, to generate spatially continuous predictive maps of Anopheles biting exposure. Our maps quantify fine-scale spatial and temporal heterogeneity in Anopheles salivary antibody seroprevalence (ranging from 9 to 99%) that serves as a proxy of exposure to Anopheles bites and advances current static maps of only Anopheles occurrence. We also developed an innovative framework to perform surveillance of malaria transmission. By incorporating antibodies against the vector and the transmissible form of malaria (sporozoite) in a joint Bayesian geostatistical model, we predict several foci of ongoing transmission. In our study, we demonstrate that antibodies specific for Anopheles salivary and sporozoite antigens are a logistically feasible metric with which to quantify and characterize heterogeneity in exposure to vector bites and malaria transmission. These approaches could readily be scaled up into existing village health volunteer surveillance networks to identify foci of residual malaria transmission, which could be targeted with supplementary interventions to accelerate progress toward elimination.
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Affiliation(s)
- Ellen A. Kearney
- Disease Elimination Program, Burnet Institute, Melbourne, VIC3004, Australia
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC3010, Australia
| | - Punam Amratia
- Malaria Atlas Project, Telethon Kids Institute, Perth, WA6009, Australia
| | - Su Yun Kang
- Malaria Atlas Project, Telethon Kids Institute, Perth, WA6009, Australia
| | - Paul A. Agius
- Disease Elimination Program, Burnet Institute, Melbourne, VIC3004, Australia
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC3010, Australia
- Biostatistics Unit, Faculty of Health, Deakin University, Melbourne, VIC3125, Australia
| | - Kefyalew Addis Alene
- Malaria Atlas Project, Telethon Kids Institute, Perth, WA6009, Australia
- Faculty of Health Sciences, Curtin University, Perth, WA6102, Australia
| | | | - Win Han Oo
- Health Security and Malaria Program, Burnet Institute Myanmar, Yangon11201, Myanmar
| | - Julia C. Cutts
- Disease Elimination Program, Burnet Institute, Melbourne, VIC3004, Australia
- Department of Medicine at the Doherty Institute, The University of Melbourne, Melbourne, VIC3000, Australia
| | - Win Htike
- Health Security and Malaria Program, Burnet Institute Myanmar, Yangon11201, Myanmar
| | | | - Zahra Razook
- Disease Elimination Program, Burnet Institute, Melbourne, VIC3004, Australia
- Institute for Physical and Mental Health and Clinical Translation, School of Medicine, Deakin University, Geelong, VIC3216, Australia
| | - Alyssa E. Barry
- Disease Elimination Program, Burnet Institute, Melbourne, VIC3004, Australia
- Institute for Physical and Mental Health and Clinical Translation, School of Medicine, Deakin University, Geelong, VIC3216, Australia
| | - Damien Drew
- Disease Elimination Program, Burnet Institute, Melbourne, VIC3004, Australia
| | - Aung Thi
- Department of Public Health, Myanmar Ministry of Health and Sports, Nay Pyi Taw15011, Myanmar
| | - Kyaw Zayar Aung
- Health Security and Malaria Program, Burnet Institute Myanmar, Yangon11201, Myanmar
| | - Htin Kyaw Thu
- Health Security and Malaria Program, Burnet Institute Myanmar, Yangon11201, Myanmar
| | - Myat Mon Thein
- Health Security and Malaria Program, Burnet Institute Myanmar, Yangon11201, Myanmar
| | - Nyi Nyi Zaw
- Health Security and Malaria Program, Burnet Institute Myanmar, Yangon11201, Myanmar
| | - Wai Yan Min Htay
- Health Security and Malaria Program, Burnet Institute Myanmar, Yangon11201, Myanmar
| | - Aung Paing Soe
- Health Security and Malaria Program, Burnet Institute Myanmar, Yangon11201, Myanmar
| | - James G. Beeson
- Disease Elimination Program, Burnet Institute, Melbourne, VIC3004, Australia
- Department of Infectious Diseases, The University of Melbourne, Melbourne, VIC3000, Australia
- Department of Microbiology, Monash University, Melbourne, VIC3800, Australia
- Central Clinical School, Monash University, Melbourne, VIC3004, Australia
| | - Julie A. Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC3010, Australia
| | - Peter W. Gething
- Malaria Atlas Project, Telethon Kids Institute, Perth, WA6009, Australia
- Faculty of Health Sciences, Curtin University, Perth, WA6102, Australia
| | - Ewan Cameron
- Malaria Atlas Project, Telethon Kids Institute, Perth, WA6009, Australia
- Faculty of Health Sciences, Curtin University, Perth, WA6102, Australia
| | - Freya J. I. Fowkes
- Disease Elimination Program, Burnet Institute, Melbourne, VIC3004, Australia
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC3010, Australia
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC3004, Australia
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Kremer R, Roth S, Bross A, Danielli A, Noam Y. Using Temporally and Spatially Resolved Measurements to Improve the Sensitivity of Fluorescence-Based Immunoassays. BIOSENSORS 2024; 14:220. [PMID: 38785694 PMCID: PMC11117981 DOI: 10.3390/bios14050220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 04/17/2024] [Accepted: 04/24/2024] [Indexed: 05/25/2024]
Abstract
Detecting low concentrations of biomarkers is essential in clinical laboratories. To improve analytical sensitivity, especially in identifying fluorescently labeled molecules, typical optical detection systems, consisting of a photodetector or camera, utilize time-resolved measurements. Taking a different approach, magnetic modulation biosensing (MMB) is a novel technology that combines fluorescently labeled probes and magnetic particles to create a sandwich assay with the target molecules. By concentrating the target molecules and then using time-resolved measurements, MMB provides the rapid and highly sensitive detection of various biomarkers. Here, we propose a novel signal-processing algorithm that enhances the detection and estimation of target molecules at low concentrations. By incorporating both temporally and spatially resolved measurements using human interleukin-8 as a target molecule, we show that the new algorithm provides a 2-4-fold improvement in the limit of detection and an ~25% gain in quantitative resolution.
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Macalinao MLM, Fornace KM, Reyes RA, Hall T, Bareng APN, Adams JH, Huon C, Chitnis CE, Luchavez JS, Tetteh KK, Yui K, Hafalla JCR, Espino FEJ, Drakeley CJ. Analytical approaches for antimalarial antibody responses to confirm historical and recent malaria transmission: an example from the Philippines. THE LANCET REGIONAL HEALTH. WESTERN PACIFIC 2023; 37:100792. [PMID: 37693871 PMCID: PMC10485684 DOI: 10.1016/j.lanwpc.2023.100792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 03/20/2023] [Accepted: 04/28/2023] [Indexed: 09/12/2023]
Abstract
Background Assessing the status of malaria transmission in endemic areas becomes increasingly challenging as countries approach elimination. Serology can provide robust estimates of malaria transmission intensities, and multiplex serological assays allow for simultaneous assessment of markers of recent and historical malaria exposure. Methods Here, we evaluated different statistical and machine learning methods for analyzing multiplex malaria-specific antibody response data to classify recent and historical exposure to Plasmodium falciparum and Plasmodium vivax. To assess these methods, we utilized samples from a health-facility based survey (n = 9132) in the Philippines, where we quantified antibody responses against 8 P. falciparum and 6 P. vivax-specific antigens from 3 sites with varying transmission intensity. Findings Measurements of antibody responses and seroprevalence were consistent with the 3 sites' known endemicity status. Among the models tested, a machine learning (ML) approach (Random Forest model) using 4 serological markers (PfGLURP R2, Etramp5.Ag1, GEXP18, and PfMSP119) gave better predictions for P. falciparum recent infection in Palawan (AUC: 0.9591, CI 0.9497-0.9684) than individual antigen seropositivity. Although the ML approach did not improve P. vivax infection predictions, ML classifications confirmed the absence of recent exposure to P. falciparum and P. vivax in both Occidental Mindoro and Bataan. For predicting historical P. falciparum and P. vivax transmission, seroprevalence and seroconversion rates based on cumulative exposure markers AMA1 and MSP119 showed reliable trends in the 3 sites. Interpretation Our study emphasizes the utility of serological markers in predicting recent and historical exposure in a sub-national elimination setting, and also highlights the potential use of machine learning models using multiplex antibody responses to improve assessment of the malaria transmission status of countries aiming for elimination. This work also provides baseline antibody data for monitoring risk in malaria-endemic areas in the Philippines. Funding Newton Fund, Philippine Council for Health Research and Development, UK Medical Research Council.
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Affiliation(s)
- Maria Lourdes M. Macalinao
- Department of Parasitology and National Reference Laboratory for Malaria and Other Parasites, Research Institute for Tropical Medicine, Department of Health, Muntinlupa City, Philippines
- Faculty of Infectious and Tropical Diseases, Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
| | - Kimberly M. Fornace
- Faculty of Infectious and Tropical Diseases, Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Ralph A. Reyes
- Department of Parasitology and National Reference Laboratory for Malaria and Other Parasites, Research Institute for Tropical Medicine, Department of Health, Muntinlupa City, Philippines
| | - Tom Hall
- Faculty of Infectious and Tropical Diseases, Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Alison Paolo N. Bareng
- Department of Parasitology and National Reference Laboratory for Malaria and Other Parasites, Research Institute for Tropical Medicine, Department of Health, Muntinlupa City, Philippines
| | | | - Christèle Huon
- Malaria Parasite Biology and Vaccines Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France
| | - Chetan E. Chitnis
- Malaria Parasite Biology and Vaccines Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France
| | - Jennifer S. Luchavez
- Department of Parasitology and National Reference Laboratory for Malaria and Other Parasites, Research Institute for Tropical Medicine, Department of Health, Muntinlupa City, Philippines
| | - Kevin K.A. Tetteh
- Faculty of Infectious and Tropical Diseases, Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Katsuyuki Yui
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
- Shionogi Global Infectious Diseases Division, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Julius Clemence R. Hafalla
- Faculty of Infectious and Tropical Diseases, Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Fe Esperanza J. Espino
- Department of Parasitology and National Reference Laboratory for Malaria and Other Parasites, Research Institute for Tropical Medicine, Department of Health, Muntinlupa City, Philippines
| | - Chris J. Drakeley
- Faculty of Infectious and Tropical Diseases, Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Biabi MFAB, Fogang B, Essangui E, Maloba F, Donkeu C, Keumoe R, Cheteug G, Magoudjou N, Slam C, Kemleu S, Efange N, Perraut R, Nsango SE, Eboumbou Moukoko CE, Assam JPA, Etoa FX, Lamb T, Ayong L. High Prevalence of Polyclonal Plasmodium falciparum Infections and Association with Poor IgG Antibody Responses in a Hyper-Endemic Area in Cameroon. Trop Med Infect Dis 2023; 8:390. [PMID: 37624328 PMCID: PMC10459087 DOI: 10.3390/tropicalmed8080390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 06/29/2023] [Accepted: 06/30/2023] [Indexed: 08/26/2023] Open
Abstract
Malaria remains a major public health problem worldwide, with eradication efforts thwarted by drug and insecticide resistance and the lack of a broadly effective malaria vaccine. In continuously exposed communities, polyclonal infections are thought to reduce the risk of severe disease and promote the establishment of asymptomatic infections. We sought to investigate the relationship between the complexity of P. falciparum infection and underlying host adaptive immune responses in an area with a high prevalence of asymptomatic parasitaemia in Cameroon. A cross-sectional study of 353 individuals aged 2 to 86 years (median age = 16 years) was conducted in five villages in the Centre Region of Cameroon. Plasmodium falciparum infection was detected by multiplex nested PCR in 316 samples, of which 278 were successfully genotyped. Of these, 60.1% (167/278) were polyclonal infections, the majority (80.2%) of which were from asymptomatic carriers. Host-parasite factors associated with polyclonal infection in the study population included peripheral blood parasite density, participant age and village of residence. The number of parasite clones per infected sample increased significantly with parasite density (r = 0.3912, p < 0.0001) but decreased with participant age (r = -0.4860, p < 0.0001). Parasitaemia and the number of clones per sample correlated negatively with total plasma levels of IgG antibodies to three highly reactive P. falciparum antigens (MSP-1p19, MSP-3 and EBA175) and two soluble antigen extracts (merozoite and mixed stage antigens). Surprisingly, we observed no association between the frequency of polyclonal infection and susceptibility to clinical disease as assessed by the recent occurrence of malarial symptoms or duration since the previous fever episode. Overall, the data indicate that in areas with the high perennial transmission of P. falciparum, parasite polyclonality is dependent on underlying host antibody responses, with the majority of polyclonal infections occurring in persons with low levels of protective anti-plasmodial antibodies.
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Affiliation(s)
- Marie Florence A Bite Biabi
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Biochemistry, Faculty of Science, University of Douala, Douala BP 2701, Cameroon
| | - Balotin Fogang
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde I, Yaounde BP 812, Cameroon
| | - Estelle Essangui
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala BP 2701, Cameroon
| | - Franklin Maloba
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
| | - Christiane Donkeu
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde I, Yaounde BP 812, Cameroon
| | - Rodrigue Keumoe
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Biochemistry, Faculty of Science, University of Yaounde I, Yaounde BP 812, Cameroon
| | - Glwadys Cheteug
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Medical Laboratory Sciences, Faculty of Science, University of Buea, Buea BP 63, Cameroon
| | - Nina Magoudjou
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Biochemistry, Faculty of Science, University of Yaounde I, Yaounde BP 812, Cameroon
| | - Celine Slam
- Department of Pathology, School of Medicine, University of Utah, 15 N Medical Drive, Salt Lake City, UT 84112, USA;
| | - Sylvie Kemleu
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
| | - Noella Efange
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Biochemistry, Faculty of Science, University of Buea, Buea BP 63, Cameroon
| | - Ronald Perraut
- Centre Pasteur du Cameroun Annex, Garoua BP 921, Cameroon;
| | - Sandrine Eveline Nsango
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala BP 2701, Cameroon
| | - Carole Else Eboumbou Moukoko
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala BP 2701, Cameroon
| | - Jean Paul Assam Assam
- Department of Microbiology, Faculty of Science, University of Yaounde I, Yaounde BP 812, Cameroon; (J.P.A.A.); (F.-X.E.)
| | - François-Xavier Etoa
- Department of Microbiology, Faculty of Science, University of Yaounde I, Yaounde BP 812, Cameroon; (J.P.A.A.); (F.-X.E.)
| | - Tracey Lamb
- Department of Pathology, School of Medicine, University of Utah, 15 N Medical Drive, Salt Lake City, UT 84112, USA;
| | - Lawrence Ayong
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
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Benié EMA, Silué KD, Ding XC, Yeo I, Assamoi JB, Tuo K, Gnagne AP, Esso LJCE, Coulibaly JT, Assi SB, Bonfoh B, Yavo W, N’Goran EK. Accuracy of a rapid diagnosis test, microscopy and loop-mediated isothermal amplification in the detection of asymptomatic Plasmodium infections in Korhogo, Northern Côte d’Ivoire. Malar J 2022; 21:111. [PMID: 35366883 PMCID: PMC8976314 DOI: 10.1186/s12936-022-04133-6] [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: 07/09/2021] [Accepted: 03/21/2022] [Indexed: 11/26/2022] Open
Abstract
Background Highly sensitive and accurate malaria diagnostic tools are essential to identify asymptomatic low parasitaemia infections. This study evaluated the performance of histidine-rich protein 2 (HRP-2) based rapid diagnostic tests (RDTs), microscopy and loop-mediated isothermal amplification (LAMP) for the detection of asymptomatic Plasmodium spp. infections in Northern Côte d’Ivoire, using nested polymerase chain reaction (nPCR) as reference. Methods A household-based survey was carried out in July 2016, in the health district of Korhogo, involving 1011 adults without malaria symptom nor history of fever during the week before recruitment. The fresh capillary blood samples were collected to detect Plasmodium infections using on HRP-2-based RDTs, microscopy and LAMP and stored as dried blood spots (DBS). A subset of the DBS (247/1011, 24.4%) was randomly selected for nPCR analyses. Additionally, venous blood samples, according to LAMP result (45 LAMP positive and 65 LAMP negative) were collected among the included participants to perform the nested PCR used as the reference. Results The prevalence of asymptomatic Plasmodium spp. infections determined by RDT, microscopy, and LAMP were 4% (95% confidence interval (CI) 2.8–5.3), 5.2% (95% CI 3.9–6.6) and 18.8% (95% CI 16.4–21.2), respectively. Considering PCR on venous blood as reference, performed on 110 samples, the sensibility and specificity were, respectively, 17.8% (95% CI 6.1–29.4) and 100% for RDT, 20.0% (95% CI 7.8–32) and 100% for microscopy, and 93.3% (95% CI 85.7–100) and 95.4% (95% CI 92.2–100) for LAMP. Conclusion In Northern Côte d’Ivoire, asymptomatic Plasmodium infection was found to be widely distributed as approximately one out of five study participants was found to be Plasmodium infected. LAMP appears currently to be the only available diagnostic method that can identify in the field this reservoir of infections and should be the method to consider for potential future active case detection interventions targeting elimination of these infections.
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Kearney EA, Agius PA, Chaumeau V, Cutts JC, Simpson JA, Fowkes FJI. Anopheles salivary antigens as serological biomarkers of vector exposure and malaria transmission: A systematic review with multilevel modelling. eLife 2021; 10:e73080. [PMID: 34939933 PMCID: PMC8860437 DOI: 10.7554/elife.73080] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 12/21/2021] [Indexed: 12/25/2022] Open
Abstract
Background Entomological surveillance for malaria is inherently resource-intensive and produces crude population-level measures of vector exposure which are insensitive in low-transmission settings. Antibodies against Anopheles salivary proteins measured at the individual level may serve as proxy biomarkers for vector exposure and malaria transmission, but their relationship is yet to be quantified. Methods A systematic review of studies measuring antibodies against Anopheles salivary antigens (PROSPERO: CRD42020185449). Multilevel modelling (to account for multiple study-specific observations [level 1], nested within study [level 2], and study nested within country [level 3]) estimated associations between seroprevalence with Anopheles human biting rate (HBR) and malaria transmission measures. Results From 3981 studies identified in literature searches, 42 studies across 16 countries were included contributing 393 study-specific observations of anti-Anopheles salivary antibodies determined in 42,764 samples. A positive association between HBR (log transformed) and seroprevalence was found; overall a twofold (100% relative) increase in HBR was associated with a 23% increase in odds of seropositivity (OR: 1.23, 95% CI: 1.10-1.37; p<0.001). The association between HBR and Anopheles salivary antibodies was strongest with concordant, rather than discordant, Anopheles species. Seroprevalence was also significantly positively associated with established epidemiological measures of malaria transmission: entomological inoculation rate, Plasmodium spp. prevalence, and malarial endemicity class. Conclusions Anopheles salivary antibody biomarkers can serve as a proxy measure for HBR and malaria transmission, and could monitor malaria receptivity of a population to sustain malaria transmission. Validation of Anopheles species-specific biomarkers is important given the global heterogeneity in the distribution of Anopheles species. Salivary biomarkers have the potential to transform surveillance by replacing impractical, inaccurate entomological investigations, especially in areas progressing towards malaria elimination. Funding Australian National Health and Medical Research Council, Wellcome Trust.
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Affiliation(s)
- Ellen A Kearney
- The McFarlane Burnet Institute of Medical Research and Public HealthMelbourneAustralia
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of MelbourneMelbourneAustralia
| | - Paul A Agius
- The McFarlane Burnet Institute of Medical Research and Public HealthMelbourneAustralia
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of MelbourneMelbourneAustralia
- Department of Epidemiology and Preventive Medicine, Monash UniversityMelbourneAustralia
| | - Victor Chaumeau
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityMae SotThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - Julia C Cutts
- The McFarlane Burnet Institute of Medical Research and Public HealthMelbourneAustralia
- Department of Medicine at the Doherty Institute, The University of MelbourneMelbourneAustralia
| | - Julie A Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of MelbourneMelbourneAustralia
| | - Freya JI Fowkes
- The McFarlane Burnet Institute of Medical Research and Public HealthMelbourneAustralia
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of MelbourneMelbourneAustralia
- Department of Epidemiology and Preventive Medicine, Monash UniversityMelbourneAustralia
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Stueber DD, Villanova J, Aponte I, Xiao Z, Colvin VL. Magnetic Nanoparticles in Biology and Medicine: Past, Present, and Future Trends. Pharmaceutics 2021; 13:943. [PMID: 34202604 PMCID: PMC8309177 DOI: 10.3390/pharmaceutics13070943] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/27/2021] [Accepted: 06/16/2021] [Indexed: 12/23/2022] Open
Abstract
The use of magnetism in medicine has changed dramatically since its first application by the ancient Greeks in 624 BC. Now, by leveraging magnetic nanoparticles, investigators have developed a range of modern applications that use external magnetic fields to manipulate biological systems. Drug delivery systems that incorporate these particles can target therapeutics to specific tissues without the need for biological or chemical cues. Once precisely located within an organism, magnetic nanoparticles can be heated by oscillating magnetic fields, which results in localized inductive heating that can be used for thermal ablation or more subtle cellular manipulation. Biological imaging can also be improved using magnetic nanoparticles as contrast agents; several types of iron oxide nanoparticles are US Food and Drug Administration (FDA)-approved for use in magnetic resonance imaging (MRI) as contrast agents that can improve image resolution and information content. New imaging modalities, such as magnetic particle imaging (MPI), directly detect magnetic nanoparticles within organisms, allowing for background-free imaging of magnetic particle transport and collection. "Lab-on-a-chip" technology benefits from the increased control that magnetic nanoparticles provide over separation, leading to improved cellular separation. Magnetic separation is also becoming important in next-generation immunoassays, in which particles are used to both increase sensitivity and enable multiple analyte detection. More recently, the ability to manipulate material motion with external fields has been applied in magnetically actuated soft robotics that are designed for biomedical interventions. In this review article, the origins of these various areas are introduced, followed by a discussion of current clinical applications, as well as emerging trends in the study and application of these materials.
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Affiliation(s)
- Deanna D. Stueber
- Center for Biomedical Engineering, School of Engineering, Brown University, 171 Meeting Street, Providence, RI 02912, USA; (D.D.S.); (J.V.); (I.A.)
| | - Jake Villanova
- Center for Biomedical Engineering, School of Engineering, Brown University, 171 Meeting Street, Providence, RI 02912, USA; (D.D.S.); (J.V.); (I.A.)
- Department of Chemistry, Brown University, 324 Brook Street, Providence, RI 02912, USA;
| | - Itzel Aponte
- Center for Biomedical Engineering, School of Engineering, Brown University, 171 Meeting Street, Providence, RI 02912, USA; (D.D.S.); (J.V.); (I.A.)
| | - Zhen Xiao
- Department of Chemistry, Brown University, 324 Brook Street, Providence, RI 02912, USA;
| | - Vicki L. Colvin
- Center for Biomedical Engineering, School of Engineering, Brown University, 171 Meeting Street, Providence, RI 02912, USA; (D.D.S.); (J.V.); (I.A.)
- Department of Chemistry, Brown University, 324 Brook Street, Providence, RI 02912, USA;
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8
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Gimenez AM, Marques RF, Regiart M, Bargieri DY. Diagnostic Methods for Non-Falciparum Malaria. Front Cell Infect Microbiol 2021; 11:681063. [PMID: 34222049 PMCID: PMC8248680 DOI: 10.3389/fcimb.2021.681063] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/31/2021] [Indexed: 11/13/2022] Open
Abstract
Malaria is a serious public health problem that affects mostly the poorest countries in the world, killing more than 400,000 people per year, mainly children under 5 years old. Among the control and prevention strategies, the differential diagnosis of the Plasmodium-infecting species is an important factor for selecting a treatment and, consequently, for preventing the spread of the disease. One of the main difficulties for the detection of a specific Plasmodium sp is that most of the existing methods for malaria diagnosis focus on detecting P. falciparum. Thus, in many cases, the diagnostic methods neglect the other non-falciparum species and underestimate their prevalence and severity. Traditional methods for diagnosing malaria may present low specificity or sensitivity to non-falciparum spp. Therefore, there is high demand for new alternative methods able to differentiate Plasmodium species in a faster, cheaper and easier manner to execute. This review details the classical procedures and new perspectives of diagnostic methods for malaria non-falciparum differential detection and the possibilities of their application in different circumstances.
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Affiliation(s)
- Alba Marina Gimenez
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Rodolfo F. Marques
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Matías Regiart
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Daniel Youssef Bargieri
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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Oboh MA, Oyebola KM, Idowu ET, Badiane AS, Otubanjo OA, Ndiaye D. Rising report of Plasmodium vivax in sub-Saharan Africa: Implications for malaria elimination agenda. SCIENTIFIC AFRICAN 2020. [DOI: 10.1016/j.sciaf.2020.e00596] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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10
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Surtees R, Stern D, Ahrens K, Kromarek N, Lander A, Kreher P, Weiss S, Hewson R, Punch EK, Barr JN, Witkowski PT, Couacy-Hymann E, Marzi A, Dorner BG, Kurth A. Development of a multiplex microsphere immunoassay for the detection of antibodies against highly pathogenic viruses in human and animal serum samples. PLoS Negl Trop Dis 2020; 14:e0008699. [PMID: 33095766 PMCID: PMC7641473 DOI: 10.1371/journal.pntd.0008699] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 11/04/2020] [Accepted: 08/11/2020] [Indexed: 11/18/2022] Open
Abstract
Surveillance of highly pathogenic viruses circulating in both human and animal populations is crucial to unveil endemic infections and potential zoonotic reservoirs. Monitoring the burden of disease by serological assay could be used as an early warning system for imminent outbreaks as an increased seroprevalance often precedes larger outbreaks. However, the multitude of highly pathogenic viruses necessitates the need to identify specific antibodies against several targets from both humans as well as from potential reservoir animals such as bats. In order to address this, we have developed a broadly reactive multiplex microsphere immunoassay (MMIA) for the detection of antibodies against several highly pathogenic viruses from both humans and animals. To this aim, nucleoproteins (NP) of Ebola virus (EBOV), Marburg virus (MARV) and nucleocapsid proteins (NP) of Crimean-Congo haemorrhagic fever virus, Rift Valley fever virus and Dobrava-Belgrade hantavirus were employed in a 5-plex assay for IgG detection. After optimisation, specific binding to each respective NP was shown by testing sera from humans and non-human primates with known infection status. The usefulness of our assay for serosurveillance was shown by determining the immune response against the NP antigens in a panel of 129 human serum samples collected in Guinea between 2011 and 2012 in comparison to a panel of 88 sera from the German blood bank. We found good agreement between our MMIA and commercial or in-house reference methods by ELISA or IIFT with statistically significant higher binding to both EBOV NP and MARV NP coupled microspheres in the Guinea panel. Finally, the MMIA was successfully adapted to detect antibodies from bats that had been inoculated with EBOV- and MARV- virus-like particles, highlighting the versatility of this technique and potentially enabling the monitoring of wildlife as well as human populations with this assay. We were thus able to develop and validate a sensitive and broadly reactive high-throughput serological assay which could be used as a screening tool to detect antibodies against several highly pathogenic viruses.
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Affiliation(s)
- Rebecca Surtees
- Biosafety Level-4 Laboratory, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Daniel Stern
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Katharina Ahrens
- Biosafety Level-4 Laboratory, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Nicole Kromarek
- Biosafety Level-4 Laboratory, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Angelika Lander
- Biosafety Level-4 Laboratory, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Petra Kreher
- Biosafety Level-4 Laboratory, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Sabrina Weiss
- Institute of Virology, Charité -Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Germany
| | - Roger Hewson
- Virology and Pathogenesis Group, National Infection Service, Public Health England, Porton Down, United Kingdom
| | - Emma K Punch
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, United Kingdom
| | - John N Barr
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, United Kingdom
| | - Peter T Witkowski
- Institute of Virology, Charité -Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Germany
| | | | - Andrea Marzi
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, United States of America
| | - Brigitte G Dorner
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Andreas Kurth
- Biosafety Level-4 Laboratory, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
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Wu L, Hall T, Ssewanyana I, Oulton T, Patterson C, Vasileva H, Singh S, Affara M, Mwesigwa J, Correa S, Bah M, D'Alessandro U, Sepúlveda N, Drakeley C, Tetteh KKA. Optimisation and standardisation of a multiplex immunoassay of diverse Plasmodium falciparum antigens to assess changes in malaria transmission using sero-epidemiology. Wellcome Open Res 2020; 4:26. [PMID: 32518839 PMCID: PMC7255915 DOI: 10.12688/wellcomeopenres.14950.1] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2020] [Indexed: 09/12/2023] Open
Abstract
Background: Antibody responses have been used to characterise transmission and exposure history in malaria-endemic settings for over a decade. Such studies have typically been conducted on well-standardised enzyme-linked immunosorbent assays (ELISAs). However, recently developed quantitative suspension array technologies (qSAT) are now capable of high-throughput and multiplexed screening of up to hundreds of analytes at a time. This study presents a customised protocol for the Luminex MAGPIX © qSAT using a diverse set of malaria antigens. The aim is to develop a standardised assay for routine serological surveillance that is implementable across laboratories and epidemiological settings. Methods: A panel of eight Plasmodium falciparum recombinant antigens, associated with long- and short-lived antibody responses, was designed for the Luminex MAGPIX © platform. The assay was optimised for key steps in the protocol: antigen-bead coupling concentration, buffer composition, serum sample dilution, and bead storage conditions. Quality control procedures and data normalisation methods were developed to address high-throughput assay processing. Antigen-specific limits of quantification (LOQs) were also estimated using both in-house and WHO reference serum as positive controls. Results: Antigen-specific bead coupling was optimised across five serum dilutions and two positive controls, resulting in concentrations operational within stable analytical ranges. Coupled beads were stable after storage at room temperature (22⁰C) for up to eight weeks. High sensitivity and specificity for distinguishing positive and negative controls at serum sample dilutions of 1:500 (AUC 0.94 95%CI 0.91-0.96) and 1:1000 (AUC 0.96 95%CI 0.94-0.98) were observed. LOQs were also successfully estimated for all analytes but varied by antigen and positive control. Conclusions: This study demonstrates that developing a standardised malaria-specific qSAT protocol for a diverse set of antigens is achievable, though further optimisations may be required. Quality control and data standardisation methods may also be useful for future analysis of large sero-epidemiological surveys.
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Affiliation(s)
- Lindsey Wu
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Tom Hall
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Isaac Ssewanyana
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
- Infectious Diseases Research Collaboration (IDRC), Kampala, P O. Box 7475, Uganda
| | - Tate Oulton
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Catriona Patterson
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Hristina Vasileva
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Susheel Singh
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
- Centre for Medical Parasitology at Department of International Health, University of Copenhagen, Copenhagen, Denmark
| | - Muna Affara
- Infectious Disease Epidemiology Department, Bernhard Nocht Institute for Tropical Medicine, Hamburg, 20359, Germany
| | - Julia Mwesigwa
- MRC Unit at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Simon Correa
- MRC Unit at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Mamadou Bah
- MRC Unit at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Umberto D'Alessandro
- MRC Unit at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Nuno Sepúlveda
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Kevin K A Tetteh
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
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12
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Wu L, Hall T, Ssewanyana I, Oulton T, Patterson C, Vasileva H, Singh S, Affara M, Mwesigwa J, Correa S, Bah M, D'Alessandro U, Sepúlveda N, Drakeley C, Tetteh KKA. Optimisation and standardisation of a multiplex immunoassay of diverse Plasmodium falciparum antigens to assess changes in malaria transmission using sero-epidemiology. Wellcome Open Res 2020; 4:26. [PMID: 32518839 PMCID: PMC7255915 DOI: 10.12688/wellcomeopenres.14950.2] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2020] [Indexed: 11/30/2022] Open
Abstract
Background: Antibody responses have been used to characterise transmission and exposure history in malaria-endemic settings for over a decade. Such studies have typically been conducted on well-standardised enzyme-linked immunosorbent assays (ELISAs). However, recently developed quantitative suspension array technologies (qSAT) are now capable of high-throughput and multiplexed screening of up to hundreds of analytes at a time. This study presents a customised protocol for the Luminex MAGPIX
© qSAT using a diverse set of malaria antigens. The aim is to develop a standardised assay for routine serological surveillance that is implementable across laboratories and epidemiological settings. Methods: A panel of eight
Plasmodium falciparum recombinant antigens, associated with long- and short-lived antibody responses, was designed for the Luminex MAGPIX
© platform. The assay was optimised for key steps in the protocol: antigen-bead coupling concentration, buffer composition, serum sample dilution, and bead storage conditions. Quality control procedures and data normalisation methods were developed to address high-throughput assay processing. Antigen-specific limits of quantification (LOQs) were also estimated using both in-house and WHO reference serum as positive controls. Results: Antigen-specific bead coupling was optimised across five serum dilutions and two positive controls, resulting in concentrations operational within stable analytical ranges. Coupled beads were stable after storage at room temperature (22⁰C) for up to eight weeks. High sensitivity and specificity for distinguishing positive and negative controls at serum sample dilutions of 1:500 (AUC 0.94 95%CI 0.91-0.96) and 1:1000 (AUC 0.96 95%CI 0.94-0.98) were observed. LOQs were also successfully estimated for all analytes but varied by antigen and positive control. Conclusions: This study demonstrates that developing a standardised malaria-specific qSAT protocol for a diverse set of antigens is achievable, though further optimisations may be required. Quality control and data standardisation methods may also be useful for future analysis of large sero-epidemiological surveys.
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Affiliation(s)
- Lindsey Wu
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Tom Hall
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Isaac Ssewanyana
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK.,Infectious Diseases Research Collaboration (IDRC), Kampala, P O. Box 7475, Uganda
| | - Tate Oulton
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Catriona Patterson
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Hristina Vasileva
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Susheel Singh
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark.,Centre for Medical Parasitology at Department of International Health, University of Copenhagen, Copenhagen, Denmark
| | - Muna Affara
- Infectious Disease Epidemiology Department, Bernhard Nocht Institute for Tropical Medicine, Hamburg, 20359, Germany
| | - Julia Mwesigwa
- MRC Unit at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Simon Correa
- MRC Unit at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Mamadou Bah
- MRC Unit at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Umberto D'Alessandro
- MRC Unit at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Nuno Sepúlveda
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Kevin K A Tetteh
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
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13
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Varela ML, Koffi D, White M, Niang M, Mbengue B, Diene Sarr F, Touré AO, Perraut R. Practical example of multiple antibody screening for evaluation of malaria control strategies. Malar J 2020; 19:117. [PMID: 32192514 PMCID: PMC7082935 DOI: 10.1186/s12936-020-03186-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 03/09/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Ongoing efforts to fight Plasmodium falciparum malaria has reduced malaria in many areas, but new tools are needed to monitor further progress, including indicators of decreasing exposure to parasite infection. Sero-surveillance is considered promising to monitor exposure, transmission and immunity. METHODS IgG responses to three antigen biomarkers were evaluated in a retrospective study involving: (i) surveys of 798 asymptomatic villagers from 2 Senegalese endemic settings conducted before 2002 and after the 2013 intensification of control measures, and (ii) in 105 symptomatic individuals from different settings in Côte d'Ivoire. Response to up to eight P. falciparum antigens, including recombinant MSP1p9 antigen and LSA141 peptide, were analysed using multiplex technology and responses to whole P. falciparum schizont extract (SE, local strain adapted to culture) were measured by ELISA. RESULTS MSP1p9 and LSA141 IgG responses were shown to be relevant indicators monitoring immune status in the different study sites both from Côte d'Ivoire and Senegal. Between 2002 and 2013, individuals participating in both studies showed higher decline of sero-positivity in young (< 15 years: range 12% to 50%) than older (> 15 years: no decline to 15%) individuals from Dielmo and Ndiop. A mathematical sero-catalytic model from the complete Dielmo/Ndiop survey was used to reconstruct declining levels of sero-positivity in more detail, demonstrating that anti-SE seroprevalence levels most accurately reflected malaria exposure in the two villages. CONCLUSION For standard screening of population immune status at sites envisaging elimination, the use of ELISA-based assays targeting selected antigens can contribute to provide important epidemiologic surveillance data to aid malaria control programmes.
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Affiliation(s)
| | - David Koffi
- Unité de Paludologie, Institut Pasteur de Côte d'Ivoire, Abidjan, Côte d'Ivoire
| | - Michael White
- Malaria Unit, Parasites and hosts, Institut Pasteur, Paris, France
| | - Makhtar Niang
- Unité d'Immunologie, Institut Pasteur de Dakar, Dakar, Senegal
| | - Babacar Mbengue
- Unité d'Immunogénétique, Institut Pasteur de Dakar, Dakar, Senegal.,Service d'Immunologie FMPO, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | | | | | - Ronald Perraut
- Unité d'Immunologie, Institut Pasteur de Dakar, Dakar, Senegal. .,Unité d'Immunogénétique, Institut Pasteur de Dakar, Dakar, Senegal. .,Centre Pasteur du Cameroun, Annexe de Garoua, Garoua, Cameroun.
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14
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Stern M, Cohen M, Danielli A. Configuration and Design of Electromagnets for Rapid and Precise Manipulation of Magnetic Beads in Biosensing Applications. MICROMACHINES 2019; 10:mi10110784. [PMID: 31731737 PMCID: PMC6915540 DOI: 10.3390/mi10110784] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 11/05/2019] [Accepted: 11/13/2019] [Indexed: 11/16/2022]
Abstract
Rapid and precise manipulation of magnetic beads on the nano and micro scales is essential in many biosensing applications, such as separating target molecules from background molecules and detecting specific proteins and DNA sequences in plasma. Accurately moving magnetic beads back and forth requires at least two adjustable magnetic field gradients. Unlike permanent magnets, electromagnets are easy to design and can produce strong and adjustable magnetic field gradients without mechanical motion, making them desirable for use in robust and safe medical devices. However, using multiple magnetic field sources to manipulate magnetic beads presents several challenges, including overlapping magnetic fields, added bulk, increased cost, and reduced durability. Here, we provide a thorough analysis, including analytical calculations, numerical simulations, and experimental measurements, of using two electromagnets to manipulate magnetic beads inside a miniature glass cell. We analyze and experimentally demonstrate different aspects of the electromagnets’ design, such as their mutual influence, the advantages and disadvantages of different pole tip geometries, and the correlation between the electromagnets’ positions and the beads’ aggregation during movement. Finally, we have devised a protocol to maximize the magnetic forces acting on magnetic beads in a two-electromagnet setup while minimizing the electromagnets’ size. We used two such electromagnets in a small footprint magnetic modulation biosensing system and detected as little as 13 ng/L of recombinant Zika virus antibodies, which enables detection of Zika IgM antibodies as early as 5 days and as late as 180 days post symptoms onset, significantly extending the number of days that the antibodies are detectable.
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15
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Bendezu J, Villasis E, Morales Ruiz S, Garro K, Infante B, Gutierrez-Loli R, Rodríguez P, Fernández-Díaz M, Gamboa D, Torres K. Evaluation of Plasmodium falciparum MSP10 and its development as a serological tool for the Peruvian Amazon region. Malar J 2019; 18:327. [PMID: 31547821 PMCID: PMC6757379 DOI: 10.1186/s12936-019-2959-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 09/11/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Different antigens are needed to characterize Plasmodium falciparum infection in terms of seroreactivity and targets for invasion inhibition, in order to guide and identify the proper use of such proteins as tools for the development of serological markers and/or as vaccine candidates. METHODS IgG responses in 84 serum samples from individuals with P. falciparum infection [classified as symptomatic (Sym) or asymptomatic (Asym)], or acute Plasmodium vivax infection, from the Peruvian Amazon region, were evaluated by enzyme-linked immunosorbent assays specific for a baculovirus-produced recombinant protein P. falciparum Merozoite Surface Protein 10 (rMSP10) and for non-EGF region selected peptides of PfMSP10 selected by a bioinformatics tool (PfMSP10-1, PfMSP10-2 and PfMSP10-3). Monoclonal antibodies against the selected peptides were evaluated by western blotting, confocal microscopy and inhibition invasion assays. RESULTS Seroreactivity analysis of the P. falciparum Sym- and Asym-infected individuals against rMSP10 showed a higher response as compared to the individuals with P. vivax acute infection. IgG responses against peptide PfMSP10-1 were weak. Interestingly high IgG response was found against peptide PfMSP10-2 and the combination of peptides PfMSP10-1 + PfMSP10-2. Monoclonal antibodies were capable of detecting native PfMSP10 on purified schizonts by western blot and confocal microscopy. A low percentage of inhibition of merozoite invasion of erythrocytes in vitro was observed when the monoclonal antibodies were compared with the control antibody against AMA-1 antigen. Further studies are needed to evaluate the role of PfMSP10 in the merozoite invasion. CONCLUSIONS The rMSP10 and the PfMSP10-2 peptide synthesized for this study may be useful antigens for evaluation of P. falciparum malaria exposure in Sym and Asym individuals from the Peruvian Amazon region. Moreover, these antigens can be used for further investigation of the role of this protein in other malaria-endemic areas.
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Affiliation(s)
- Jorge Bendezu
- Laboratorios de Investigación y Desarrollo, FARVET, Carretera Panamericana Sur No 766 km 198.5, Chincha Alta, Ica, Peru.
| | - Elizabeth Villasis
- Laboratorios de Investigación y Desarrollo "Abraham Vaisberg Wolach, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Instituto de Medicina Tropical Alexander von Humboldt-Universidad Peruana Cayetano Heredia, Av. Honorio Delgado 430, San Martín de Porres, Lima, Peru
| | - Sandra Morales Ruiz
- Laboratorios de Investigación y Desarrollo, FARVET, Carretera Panamericana Sur No 766 km 198.5, Chincha Alta, Ica, Peru
| | - Katherine Garro
- Laboratorios de Investigación y Desarrollo "Abraham Vaisberg Wolach, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Berónica Infante
- Laboratorios de Investigación y Desarrollo "Abraham Vaisberg Wolach, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Renzo Gutierrez-Loli
- Laboratorios de Investigación y Desarrollo "Abraham Vaisberg Wolach, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Pamela Rodríguez
- Laboratorios de Investigación y Desarrollo "Abraham Vaisberg Wolach, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Manolo Fernández-Díaz
- Laboratorios de Investigación y Desarrollo, FARVET, Carretera Panamericana Sur No 766 km 198.5, Chincha Alta, Ica, Peru
| | - Dionicia Gamboa
- Laboratorios de Investigación y Desarrollo "Abraham Vaisberg Wolach, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Instituto de Medicina Tropical Alexander von Humboldt-Universidad Peruana Cayetano Heredia, Av. Honorio Delgado 430, San Martín de Porres, Lima, Peru
| | - Katherine Torres
- Laboratorios de Investigación y Desarrollo "Abraham Vaisberg Wolach, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru.
- Instituto de Medicina Tropical Alexander von Humboldt-Universidad Peruana Cayetano Heredia, Av. Honorio Delgado 430, San Martín de Porres, Lima, Peru.
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16
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Teige LH, Kumar S, Johansen GM, Wessel Ø, Vendramin N, Lund M, Rimstad E, Boysen P, Dahle MK. Detection of Salmonid IgM Specific to the Piscine Orthoreovirus Outer Capsid Spike Protein Sigma 1 Using Lipid-Modified Antigens in a Bead-Based Antibody Detection Assay. Front Immunol 2019; 10:2119. [PMID: 31552049 PMCID: PMC6743345 DOI: 10.3389/fimmu.2019.02119] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 08/22/2019] [Indexed: 11/13/2022] Open
Abstract
Bead-based multiplex immunoassays are promising tools for determination of the specific humoral immune response. In this study, we developed a multiplexed bead-based immunoassay for the detection of Atlantic salmon (Salmo salar) antibodies against Piscine orthoreovirus (PRV). Three different genotypes of PRV (PRV-1, PRV-2, and PRV-3) cause disease in farmed salmonids. The PRV outer capsid spike protein σ1 is predicted to be a host receptor binding protein and a target for neutralizing and protective antibodies. While recombinant σ1 performed poorly as an antigen to detect specific antibodies, N-terminal lipid modification of recombinant PRV-1 σ1 enabled sensitive detection of specific IgM in the bead-based assay. The specificity of anti-PRV-1 σ1 antibodies was confirmed by western blotting and pre-adsorption of plasma. Binding of non-specific IgM to beads coated with control antigens also increased after PRV infection, indicating a release of polyreactive antibodies. This non-specific binding was reduced by heat treatment of plasma. The same immunoassay also detected anti-PRV-3 σ1 antibodies from infected rainbow trout. In summary, a refined bead based immunoassay created by N-terminal lipid-modification of the PRV-1 σ1 antigen allowed sensitive detection of anti-PRV-1 and anti-PRV-3 antibodies from salmonids.
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Affiliation(s)
- Lena Hammerlund Teige
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Subramani Kumar
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway.,Stem Cell and Cancer Biology Lab, Centre for Biotechnology, Anna University, Chennai, India
| | - Grethe M Johansen
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Øystein Wessel
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Niccolò Vendramin
- National Institute of Aquatic Resources, Technical University of Denmark, Lyngby, Denmark
| | - Morten Lund
- Department of Fish Health, Norwegian Veterinary Institute, Oslo, Norway.,PatoGen, Alesund, Norway
| | - Espen Rimstad
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Preben Boysen
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Maria K Dahle
- Department of Fish Health, Norwegian Veterinary Institute, Oslo, Norway
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17
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Surendra H, Wijayanti MA, Murhandarwati EH, Irnawati, Yuniarti T, Mardiati, Herdiana, Sumiwi ME, Hawley WA, Lobo NF, Cook J, Drakeley C, Supargiyono. Analysis of serological data to investigate heterogeneity of malaria transmission: a community-based cross-sectional study in an area conducting elimination in Indonesia. Malar J 2019; 18:227. [PMID: 31286973 PMCID: PMC6615161 DOI: 10.1186/s12936-019-2866-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 07/03/2019] [Indexed: 01/22/2023] Open
Abstract
Background Analysis of anti-malarial antibody responses has the potential to improve characterization of the variation in exposure to infection in low transmission settings, where conventional measures, such as entomological estimates and parasitaemia point prevalence become less sensitive and expensive to measure. This study evaluates the use of sero-epidemiological analysis to investigate heterogeneity of transmission in area conducting elimination in Indonesia. Methods Filter paper bloodspots and epidemiological data were collected through a community-based cross-sectional study conducted in two sub-districts in Sabang municipality, Aceh province, Indonesia in 2013. Antibody responses to merozoite surface protein 1 (MSP-119) and apical membrane antigen 1 (AMA-1) for Plasmodium falciparum and Plasmodium vivax were measured using indirect enzyme-linked immunosorbent assay (ELISA). Seroconversion rates (SCR) were estimated by fitting a simple reversible catalytic model to seroprevalence data for each antibody. Spatial analysis was performed using a Normal model (SaTScan v.9.4.2) to identify the clustering of higher values of household antibody responses. Multiple logistic regression was used to investigate factors associated with exposure. Results 1624 samples were collected from 605 households. Seroprevalence to any P. falciparum antigen was higher than to any P. vivax antigen, 6.9% (95% CI 5.8–8.2) vs 2.0% (95% CI 1.4–2.8). SCR estimates suggest that there was a significant change in P. falciparum transmission with no exposure seen in children under 5 years old. Plasmodium falciparum SCR in over 5 years old was 0.008 (95% CI 0.003–0.017) and 0.012 (95% CI 0.005–0.030) in Sukakarya and Sukajaya sub-districts, respectively. Clusters of exposure were detected for both P. falciparum and P. vivax, most of them in Sukajaya sub-district. Higher age, P. vivax seropositivity and use of long-lasting insecticide-treated bed net (LLIN) were associated with higher P. falciparum exposure. Conclusion Analysis of community-based serological data helps describe the level of transmission, heterogeneity and factors associated with malaria transmission in Sabang. This approach could be an important additional tool for malaria monitoring and surveillance in low transmission settings in Indonesia. Electronic supplementary material The online version of this article (10.1186/s12936-019-2866-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Henry Surendra
- Infection Biology Department, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK. .,Centre for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia.
| | - Mahardika A Wijayanti
- Centre for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia.,Department of Parasitology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia
| | - Elsa H Murhandarwati
- Centre for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia.,Department of Parasitology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia
| | - Irnawati
- Sabang Municipal Health Office, Sabang, Aceh, Indonesia
| | | | - Mardiati
- Sabang Municipal Health Office, Sabang, Aceh, Indonesia
| | - Herdiana
- Child Survival and Development Cluster, UNICEF Aceh Field Office, Jakarta, Indonesia
| | - Maria E Sumiwi
- Child Survival and Development Cluster, UNICEF Aceh Field Office, Jakarta, Indonesia
| | - William A Hawley
- Child Survival and Development Cluster, UNICEF Indonesia Country Office, Jakarta, Indonesia
| | - Neil F Lobo
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Jackie Cook
- MRC Tropical Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Chris Drakeley
- Infection Biology Department, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Supargiyono
- Centre for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia.,Department of Parasitology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia
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18
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Belardin LB, Antoniassi MP, Camargo M, Intasqui P, Fraietta R, Bertolla RP. Semen levels of matrix metalloproteinase (MMP) and tissue inhibitor of metallorproteinases (TIMP) protein families members in men with high and low sperm DNA fragmentation. Sci Rep 2019; 9:903. [PMID: 30696858 PMCID: PMC6351682 DOI: 10.1038/s41598-018-37122-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 11/23/2018] [Indexed: 12/20/2022] Open
Abstract
Matrix Metalloproteinases (MMPs) and their regulators – Tissue Inhibitors of Matrix Metalloproteinases (TIMPs) – participate in extracellular matrix remodeling, fibrosis, and semen liquefaction, as well as to inflammatory activity. Seminal plasma has been shown to contain MMPs (MMP-2 and MMP-9) and TIMPs (TIMP-1 and TIMP-2). Also, a link between MMPs gene expression and excessive reactive oxygen species (ROS) has been established. In semen, ROS are associated with altered sperm function and increased DNA fragmentation. In this study, it is hypothesized that seminal MMPs and TIMPs levels are associated with sperm DNA fragmentation due to the fact that MMPs have been associated with semen quality. We also hypothesized that these proteins could predict DNA fragmentation status in sperm. Therefore, this study set out to verify if sperm DNA fragmentation levels relate to seminal levels of members of the MMP and TIMP protein families. The High sperm DNA fragmentation group presented lower seminal plasma levels of MMP-2, MMP-7, TIMP-1, TIMP-2 and TIMP-4 when compared to Low sperm DNA fragmentation group. Also, samples in the high sperm DNA fragmentation group presented higher acrosome integrity and lower mitochondrial activity levels when compared to low sperm DNA fragmentation samples. In the logistic regression analysis, MMP-2, MMP-7, and TIMP-4 classified samples as low and high sperm DNA fragmentation, with an overall model fit of 74.5%. Results from this study may demonstrate a specific inflammatory mechanism in samples with high sperm DNA fragmentation. This, in turn, can lead to the development of new studies regarding this mechanism and, in the future, create an opportunity to treat these patients for sperm DNA fragmentation by treating inflammatory seminal activity.
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Affiliation(s)
| | | | - Mariana Camargo
- Department of Surgery, Division of Urology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Paula Intasqui
- Department of Surgery, Division of Urology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Renato Fraietta
- Department of Surgery, Division of Urology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Ricardo Pimenta Bertolla
- Department of Surgery, Division of Urology, Universidade Federal de São Paulo, São Paulo, Brazil. .,Hospital São Paulo, São Paulo, Brazil.
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19
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Specificity of the IgG antibody response to Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, and Plasmodium ovale MSP1 19 subunit proteins in multiplexed serologic assays. Malar J 2018; 17:417. [PMID: 30413163 PMCID: PMC6230236 DOI: 10.1186/s12936-018-2566-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 11/01/2018] [Indexed: 11/21/2022] Open
Abstract
Background Multiplex bead assays (MBA) that measure IgG antibodies to the carboxy-terminal 19-kDa sub-unit of the merozoite surface protein 1 (MSP119) are currently used to determine malaria seroprevalence in human populations living in areas with both stable and unstable transmission. However, the species specificities of the IgG antibody responses to the malaria MSP119 antigens have not been extensively characterized using MBA. Methods Recombinant Plasmodium falciparum (3D7), Plasmodium malariae (China I), Plasmodium ovale (Nigeria I), and Plasmodium vivax (Belem) MSP119 proteins were covalently coupled to beads for MBA. Threshold cut-off values for the assays were estimated using sera from US citizens with no history of foreign travel and by receiver operator characteristic curve analysis using diagnostic samples. Banked sera from experimentally infected chimpanzees, sera from humans from low transmission regions of Haiti and Cambodia (N = 12), and elutions from blood spots from humans selected from a high transmission region of Mozambique (N = 20) were used to develop an antigen competition MBA for antibody cross-reactivity studies. A sub-set of samples was further characterized using antibody capture/elution MBA, IgG subclass determination, and antibody avidity measurement. Results Total IgG antibody responses in experimentally infected chimpanzees were species specific and could be completely suppressed by homologous competitor protein at a concentration of 10 μg/ml. Eleven of 12 samples from the low transmission regions and 12 of 20 samples from the high transmission area had antibody responses that were completely species specific. For 7 additional samples, the P. falciparum MSP119 responses were species specific, but various levels of incomplete heterologous competition were observed for the non-P. falciparum assays. A pan-malaria MSP119 cross-reactive antibody response was observed in elutions of blood spots from two 20–30 years old Mozambique donors. The antibody response from one of these two donors had low avidity and skewed almost entirely to the IgG3 subclass. Conclusions Even when P. falciparum, P. malariae, P. ovale, and P. vivax are co-endemic in a high transmission setting, most antibody responses to MSP119 antigens are species-specific and are likely indicative of previous infection history. True pan-malaria cross-reactive responses were found to occur rarely. Electronic supplementary material The online version of this article (10.1186/s12936-018-2566-0) contains supplementary material, which is available to authorized users.
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20
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Optimization of a magnetic bead-based assay (MAGPIX ®-Luminex) for immune surveillance of exposure to malaria using multiple Plasmodium antigens and sera from different endemic settings. Malar J 2018; 17:324. [PMID: 30189885 PMCID: PMC6127931 DOI: 10.1186/s12936-018-2465-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 08/27/2018] [Indexed: 01/08/2023] Open
Abstract
Background Serological markers are potentially useful tools for monitoring the progress of malaria control programs, but a better understanding of antibody response dynamics is necessary. The use of a magnetic bead-based immunoassay (MBA) is advantageous compared to ELISA, due to its multiplexing capacity, but limited information is available on the standardization and validation of this assay. Methods Several parameters for multiplex testing of antibodies to Plasmodium antigens were analysed using a set of 4 antigens and 98 sera from Senegalese rural asymptomatic and urban symptomatic individuals. The 4 antigens included Plasmodium falciparum CSP and PfAMA1 peptides, recombinant P. falciparum MSP4p20 and a Plasmodium malariae CSP (PmCSP) peptide. Comparisons with ELISA were done using MSP4p20 and whole schizont extract (SE) antigens. Results The use of fewer beads (1000 beads per well instead of 2000) and 5 µg of antigen per 106 bead were validated as lower amounts. The use of a carrier protein (BSA) was shown to be critical when using peptides and the effect of a 24 h delayed measures was evaluated (5–25% signal decrease). Analysis of Ab responses showed almost equally high levels and prevalence in all transmission settings. Clear distinctions between rural and urban malaria were noted using PmCSP and SE antigens. Conclusions This study underlines the importance of further optimization of the MBA technique and highlights the interest of using multistage/multispecies antigens for surveillance of malaria in endemic settings.
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21
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Oyebola KM, Aina OO, Bah MM, Ajibaye S, Correa S, Awandare GA, Amambua-Ngwa A. Assessing naturally acquired immune response and malaria treatment outcomes in Lagos, Nigeria. AAS Open Res 2018. [DOI: 10.12688/aasopenres.12828.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background: There are emerging reports of poor efficacy of artemisinin-based combination treatment (ACT). However, mutations on the Kelch-13 gene marking delayed parasite clearance have no clinically defined relationship with ACT resistance across Africa. With increasing malaria control efforts, declining acquired immunity could be responsible for varying drug response profiles that may be dependent on levels of exposure to infections. To examine antibody responses against malaria and the influence on the efficacy of artemether-lumefantrine (AL), plasma samples were collected, prior to treatment, from individuals presenting with uncomplicated malaria. Methods: Participants were stratified into two groups: early (within 24 hours, N = 20) and late (between 48 – 72 hours, N = 30) parasite clearance after treatment, as determined by var gene acidic terminal sequence (varATS) polymerase chain reaction. Magnetic bead-based luminex assay was used to profile antibody responses specific to a panel of 21 Plasmodium falciparum sporozoite, merozoite and An. gambiae salivary antigens. Results: Median fluorescence intensity (MFI) of the antibodies was highest against glutamate-rich protein (GLURP-R0) and lowest against merozoite surface protein (MSP2) antigen. Analysis showed a positive correlation between expression of immunity and age of individuals (P = 0.023). However, there was no association between parasite density and antibody responses, except a significant positive relationship with reticulocyte binding protein-like homologue 5 (Rh5), P = 0.047; Plasmodium exported protein (Hyp2), P = 0.037 and merozoite surface protein 11 (H103), P = 0.038. Though higher levels of antibodies against erythrocyte binding antigens (EBA 140 and 175), MSP1.19, GLURP, circumsporozoite protein (CSP) and Rh4.2 were observed in individuals who recorded early parasite clearance, there was no significant difference in antibody responses in the early and late parasitological response groups. Conclusions: Characterization of additional markers in larger populations is required to reveal potential immunological correlates of drug efficacy.
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22
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Perraut R, Varela ML, Loucoubar C, Niass O, Sidibé A, Tall A, Trape JF, Wotodjo AN, Mbengue B, Sokhna C, Vigan-Womas I, Touré A, Richard V, Mercereau-Puijalon O. Serological signatures of declining exposure following intensification of integrated malaria control in two rural Senegalese communities. PLoS One 2017; 12:e0179146. [PMID: 28609450 PMCID: PMC5469466 DOI: 10.1371/journal.pone.0179146] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/24/2017] [Indexed: 01/26/2023] Open
Abstract
Recent control scale-up has reduced malaria in many areas but new tools are needed to monitor further progress, including indicators of decreasing exposure to parasite infection. Although serology is considered a promising approach in this regard, the serological impact of control interventions has been so far studied using indirect quantification of exposure. Cohort surveys concomitantly recording entomological and malariometric indices have been conducted in two Senegalese settings where supervised control intensification implemented in 2006 shifted malaria from historically holoendemic in Dielmo and mesoendemic in Ndiop to hypoendemic in both settings by 2013. We analyse here serological signatures of declining transmission using archived blood samples. Responses against ten pre-erythrocytic and erythrocytic antigens from Plasmodium falciparum and P. malariae alongside an Anopheles gambiae salivary gland antigen were analysed. Cross-sectional surveys conducted before (2002) and after (2013) control intensification showed a major impact of control intensification in both settings. The age-associated prevalence, magnitude and breadth of the IgG responses to all antigens were village-specific in 2002. In 2013, remarkably similar patterns were observed in both villages, with marginal responses against all parasite antigens in the 0-5y children and reduced responses in all previously seropositive age groups. Waning of humoral responses of individuals who were immune at the time of control intensification was studied from 2006 to 2013 using yearly samplings. Longitudinal data were analysed using the Cochran-Armittage trend test and an age-related reversible catalytic conversion model. This showed that the antigen-specific antibody declines were more rapid in older children than adults. There was a strong association of antibody decline with the declining entomological inoculation rate. We thus identified serological markers of declining exposure to malaria parasites that should help future monitoring of progress towards malaria elimination.
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Affiliation(s)
- Ronald Perraut
- Institut Pasteur de Dakar, Unité d’Immunologie, Dakar, Sénégal
- * E-mail:
| | - Marie-Louise Varela
- Institut Pasteur de Dakar, G4 Biostatistiques Bioinformatique et Modélisation, Dakar, Sénégal
| | - Cheikh Loucoubar
- Institut Pasteur de Dakar, G4 Biostatistiques Bioinformatique et Modélisation, Dakar, Sénégal
| | - Oumy Niass
- Institut Pasteur de Dakar, Unité d’Immunologie, Dakar, Sénégal
| | - Awa Sidibé
- Institut Pasteur de Dakar, Unité d’Immunologie, Dakar, Sénégal
| | - Adama Tall
- Institut Pasteur de Dakar, Unité d’Epidémiologie, Dakar, Sénégal
| | | | | | - Babacar Mbengue
- Institut Pasteur de Dakar, Unité d’Immunogénétique, Dakar, Sénégal
| | - Cheikh Sokhna
- Institut de Recherche pour le Développement (IRD), URMITE, Dakar, Sénégal
| | - Inès Vigan-Womas
- Institut Pasteur de Madagascar, Unité d’Immunologie des Maladies Infectieuses, Antanarivo, Madagascar
- Institut Pasteur, Department of Parasitology and Insect Vectors, 25 Rue du Dr Roux, Paris, France
| | - Aissatou Touré
- Institut Pasteur de Dakar, Unité d’Immunologie, Dakar, Sénégal
| | - Vincent Richard
- Institut Pasteur de Dakar, Unité d’Epidémiologie, Dakar, Sénégal
| | - Odile Mercereau-Puijalon
- Institut Pasteur, Department of Parasitology and Insect Vectors, 25 Rue du Dr Roux, Paris, France
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23
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Teige LH, Lund M, Haatveit HM, Røsæg MV, Wessel Ø, Dahle MK, Storset AK. A bead based multiplex immunoassay detects Piscine orthoreovirus specific antibodies in Atlantic salmon (Salmo salar). FISH & SHELLFISH IMMUNOLOGY 2017; 63:491-499. [PMID: 28254501 DOI: 10.1016/j.fsi.2017.02.043] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 02/16/2017] [Accepted: 02/24/2017] [Indexed: 06/06/2023]
Abstract
Future growth in aquaculture relies strongly on the control of diseases and pathogens. Vaccination has been a successful strategy for obtaining control of bacterial diseases in fish, but for viral diseases, vaccine development has been more challenging. Effective long-term protection against viral infections is not yet fully understood for fish, and in addition, optimal tools to monitor adaptive immunity are limited. Assays that can detect specific antibodies produced in response to viral infection in fish are still in their early development. Multiplex bead based assays have many advantages over traditional assays, since they are more sensitive and allow detection of multiple antigen-specific antibodies simultaneously in very small amounts of plasma or serum. In the present study, a bead based assay have been developed for detection of plasma IgM directed against Piscine orthoreovirus (PRV), the virus associated with the disease Heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon. Using recombinant PRV proteins coated on beads, antibodies targeting the structural outer capsid protein μ1 and the non-structural protein μNS were detected. Results from a PRV cohabitation challenge trial indicated that the antibody production was initiated approximately two weeks after the peak phase of PRV infection, coinciding with typical HSMI pathology. Thereafter, the antibody production increased while the epicardial inflammation became less prominent. In conclusion, the novel assay can detect PRV-specific antibodies that may play a role in viral defence. The bead-based immunoassay represents a valuable tool for studies on HSMI and possibly other diseases in aquaculture.
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Affiliation(s)
- Lena Hammerlund Teige
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, N-0454 Oslo, Norway
| | - Morten Lund
- Norwegian Veterinary Institute, N-0454 Oslo, Norway
| | - Hanne M Haatveit
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, N-0454 Oslo, Norway
| | - Magnus Vikan Røsæg
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, N-0454 Oslo, Norway; SalMar ASA, N-7266 Kverva, Norway
| | - Øystein Wessel
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, N-0454 Oslo, Norway
| | - Maria K Dahle
- Norwegian Veterinary Institute, N-0454 Oslo, Norway.
| | - Anne K Storset
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, N-0454 Oslo, Norway
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24
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Koffi D, Varela ML, Loucoubar C, Beourou S, Vigan-Womas I, Touré A, Djaman JA, Touré AO, Perraut R. Longitudinal analysis of antibody responses in symptomatic malaria cases do not mirror parasite transmission in peri-urban area of Cote d'Ivoire between 2010 and 2013. PLoS One 2017; 12:e0172899. [PMID: 28245264 PMCID: PMC5330500 DOI: 10.1371/journal.pone.0172899] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Accepted: 02/10/2017] [Indexed: 11/19/2022] Open
Abstract
Background In the agenda towards malaria eradication, assessment of both malaria exposure and efficacy of anti-vectorial and therapeutic strategies is a key component of management and the follow-up of field interventions. The simultaneous use of several antigens (Ags) as serological markers has the potential for accurate evaluation of malaria exposure. Here we aimed to measure the longitudinal evolution of the background levels of immunity in an urban setting in confirmed clinical cases of malaria. Methods A retrospective serological cross-sectional study on was carried out using 234 samples taken from 2010 to 2013 in peri-urban sentinel facility of Cote d’Ivoire. Antibody responses to recombinant proteins or BSA-peptides, 8 Plasmodium falciparum (PfAMA1, PfMSP4, PfMSP1, PfEMP1-DBL1α1-PF13, PfLSA1-41, PfLSA3-NR2, PfGLURP and PfCSP), one P. malariae (PmCSP) and one Anopheles gambiae salivary (gSG6-P1) antigens were measured using magnetic bead-based multiplex immunoassay (MBA). Total anti- P. falciparum IgG responses against schizont lysate from african 07/03 strain (adapted to culture) and 3D7 strain was measured by ELISA. Results High prevalence (7–93%) and levels of antibody responses to most of the antigens were evidenced. However, analysis showed only marginal decreasing trend of Ab responses from 2010 to 2013 that did not parallel the reduction of clinical malaria prevalence following the implementation of intervention in this area. There was a significant inverse correlation between Ab responses and parasitaemia (P<10−3, rho = 0.3). The particular recruitment of asymptomatic individuals in 2011 underlined a high background level of immunity almost equivalent to symptomatic patients, possibly obscuring observable yearly variations. Conclusion The use of cross-sectional clinical malaria surveys and MBA can help to identify endemic sites where control measures have unequal impact providing relevant information about population immunity and possible decrease of transmission. However, when immunity is substantially boosted despite observable clinical decline, a larger cohort including asymptomatic recruitment is needed to monitor the impact of control measures on level of immunity.
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Affiliation(s)
- David Koffi
- Institut Pasteur de Côte d’Ivoire, Unité de Paludologie, Abidjan, Côte d’Ivoire
- Université Félix Houphouet Boigny, UFR Biosciences, Abidjan, Côte d’Ivoire
| | | | - Cheikh Loucoubar
- Institut Pasteur de Dakar, G4 Biostatistiques Bioinformatique et Modélisation, Dakar, Sénégal
| | - Sylvain Beourou
- Institut Pasteur de Côte d’Ivoire, Unité de Paludologie, Abidjan, Côte d’Ivoire
| | - Inès Vigan-Womas
- Institut Pasteur, Unité d’Immunologie Moléculaire des Parasites, Paris, France
- Institut Pasteur de Madagascar, Unité d’Immunologie, Antanarivo, Madagascar
| | - Aissatou Touré
- Institut Pasteur de Dakar, Unité d’Immunologie, Dakar, Sénégal
| | | | | | - Ronald Perraut
- Institut Pasteur de Dakar, Unité d’Immunologie, Dakar, Sénégal
- * E-mail:
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25
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Kerkhof K, Sluydts V, Willen L, Kim S, Canier L, Heng S, Tsuboi T, Sochantha T, Sovannaroth S, Ménard D, Coosemans M, Durnez L. Serological markers to measure recent changes in malaria at population level in Cambodia. Malar J 2016; 15:529. [PMID: 27809852 PMCID: PMC5096337 DOI: 10.1186/s12936-016-1576-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Accepted: 10/27/2016] [Indexed: 11/10/2022] Open
Abstract
Background Serological markers for exposure to different Plasmodium species have recently been used in multiplex immunoassays based on the Luminex technology. However, interpretation of the assay results requires consideration of the half-life of specific antibodies against these markers. Therefore, the aim of the present study was to document the half-life of malaria specific serological makers, as well as assessing the sensitivity of these markers to pick up recent changes in malaria exposure. Methods A recently developed multiplex immunoassay was used to measure the intensity of antibody (Ab) responses against 19 different Plasmodium specific antigens, covering different human malaria parasites and two vector saliva antigens. Therefore, 8439 blood samples from five cross-sectional surveys in Ratanakiri, Cambodia, were analysed. These involve a random selection from two selected surveys, and an additional set of blood samples of individuals that were randomly re-sampled three, four or five times. A generalized estimating equation model and linear regression models were fitted on log transformed antibody intensity data. Results Results showed that most (17/21) Ab-responses are higher in PCR positive than PCR negative individuals. Furthermore, these antibody-responses follow the same upward trend within each age group. Estimation of the half-lives showed differences between serological markers that reflect short- (seasonal) and long-term (year round) transmission trends. Ab levels declined significantly together with a decrease of PCR prevalence in a group of malaria endemic villages. Conclusion For Plasmodium falciparum, antibodies against LSA3.RE, GLURP and Pf.GLURP.R2 are most likely to be a reflexion of recent (range from 6 to 8 months) exposure in the Mekong Subregion. PvEBP is the only Plasmodium vivax Ag responding reasonably well, in spite of an estimated Ab half-life of more than 1 year. The use of Ab intensity data rather dichotomizing the continuous Ab-titre data (positive vs negative) will lead to an improved approach for serological surveillance. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1576-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Karen Kerkhof
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium. .,Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.
| | - Vincent Sluydts
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.,Department of Biology, University of Antwerp, Antwerp, Belgium
| | - Laura Willen
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.,Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Saorin Kim
- Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Lydie Canier
- Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Somony Heng
- National Centre for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Tho Sochantha
- National Centre for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Siv Sovannaroth
- National Centre for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Didier Ménard
- Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Marc Coosemans
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.,Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Lies Durnez
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
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26
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Yin F, Chan JFW, Zhu Q, Fu R, Chen JHK, Choi GKY, Tee KM, Li L, Qian S, Yam WC, Lu G, Yuen KY. Development and in-use evaluation of a novel Luminex MicroPlex microsphere-based (TRIOL) assay for simultaneous identification of Mycobacterium tuberculosis and detection of first-line and second-line anti-tuberculous drug resistance in China. J Clin Pathol 2016; 70:342-349. [PMID: 27646524 DOI: 10.1136/jclinpath-2016-203952] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 08/23/2016] [Accepted: 08/28/2016] [Indexed: 11/03/2022]
Abstract
AIMS Rapid and accurate diagnostic assays with simultaneous microbial identification and drug resistance detection are essential for optimising treatment and control of tuberculosis. METHODS We developed a novel multiplex (TRIOL, Tuberculosis-Rifampicin-Isoniazid-Ofloxacin-Luminex) assay using the Luminex xMAP system that simultaneously identifies Mycobacterium tuberculosis and detects resistance to first-line and second-line anti-tuberculous drugs, and compared its performance with that by PCR sequencing, using phenotypic drug susceptibility testing as the gold standard. RESULTS Identification of M. tuberculosis by the TRIOL assay was highly sensitive (100%) and specific (100%). The overall drug-specific specificities were excellent (100%). The overall sensitivity of the TRIOL assay was lower than that of the PCR-sequencing assays (72.4% vs 82.8%) because of a lower sensitivity of detecting rifampicin resistance (71.4% vs 92.9%). The sensitivity of detecting isoniazid and ofloxacin resistance was as good as the PCR-sequencing assays. Importantly, the TRIOL assay did not miss any mutations that were included in the assay. All of the resistant isolates that were missed had uncommon mutations or unknown resistance mechanisms that were not included in the assay. CONCLUSIONS The TRIOL assay has higher throughput, lower cost and is less labour intensive than the PCR-sequencing assays. The TRIOL assay is advantageous in having the capability to detect resistance to multiple drugs and an open-architecture system that allows addition of more specific primers to detect uncommon mutations. Inclusion of additional primers for the identification of non-tuberculous mycobacteria, spoligotyping and improvement of rifampicin resistance detection would enhance the use of the TRIOL assay in future clinical and epidemiological studies.
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Affiliation(s)
- Feifei Yin
- Key Laboratory of Translation Medicine Tropical Diseases, Department of Ministry of Education, Hainan Medical University, Haikou, Hainan, China.,Department of Pathogen Biology, Hainan Medical University, Haikou, Hainan, China
| | - Jasper Fuk-Woo Chan
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China.,Department of Microbiology, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China.,Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China.,Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China
| | - Qixuan Zhu
- Key Laboratory of Translation Medicine Tropical Diseases, Department of Ministry of Education, Hainan Medical University, Haikou, Hainan, China.,Department of Pathogen Biology, Hainan Medical University, Haikou, Hainan, China
| | - Ruijia Fu
- Key Laboratory of Translation Medicine Tropical Diseases, Department of Ministry of Education, Hainan Medical University, Haikou, Hainan, China.,Department of Pathogen Biology, Hainan Medical University, Haikou, Hainan, China
| | - Jonathan Hon-Kwan Chen
- Department of Microbiology, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China
| | - Garnet Kwan-Yue Choi
- Department of Microbiology, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China
| | - Kah-Meng Tee
- Department of Microbiology, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China
| | - Lihua Li
- Key Laboratory of Translation Medicine Tropical Diseases, Department of Ministry of Education, Hainan Medical University, Haikou, Hainan, China.,Department of Pathogen Biology, Hainan Medical University, Haikou, Hainan, China
| | - Shiuyun Qian
- Key Laboratory of Translation Medicine Tropical Diseases, Department of Ministry of Education, Hainan Medical University, Haikou, Hainan, China.,Department of Pathogen Biology, Hainan Medical University, Haikou, Hainan, China
| | - Wing-Cheong Yam
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China.,Department of Microbiology, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China.,Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China.,Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China
| | - Gang Lu
- Key Laboratory of Translation Medicine Tropical Diseases, Department of Ministry of Education, Hainan Medical University, Haikou, Hainan, China.,Department of Pathogen Biology, Hainan Medical University, Haikou, Hainan, China
| | - Kwok-Yung Yuen
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China.,Department of Microbiology, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China.,Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China.,Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China
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