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Anwar MN, Smith L, Devine A, Mehra S, Walker CR, Ivory E, Conway E, Mueller I, McCaw JM, Flegg JA, Hickson RI. Mathematical models of Plasmodium vivax transmission: A scoping review. PLoS Comput Biol 2024; 20:e1011931. [PMID: 38483975 DOI: 10.1371/journal.pcbi.1011931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 03/26/2024] [Accepted: 02/19/2024] [Indexed: 03/27/2024] Open
Abstract
Plasmodium vivax is one of the most geographically widespread malaria parasites in the world, primarily found across South-East Asia, Latin America, and parts of Africa. One of the significant characteristics of the P. vivax parasite is its ability to remain dormant in the human liver as hypnozoites and subsequently reactivate after the initial infection (i.e. relapse infections). Mathematical modelling approaches have been widely applied to understand P. vivax dynamics and predict the impact of intervention outcomes. Models that capture P. vivax dynamics differ from those that capture P. falciparum dynamics, as they must account for relapses caused by the activation of hypnozoites. In this article, we provide a scoping review of mathematical models that capture P. vivax transmission dynamics published between January 1988 and May 2023. The primary objective of this work is to provide a comprehensive summary of the mathematical models and techniques used to model P. vivax dynamics. In doing so, we aim to assist researchers working on mathematical epidemiology, disease transmission, and other aspects of P. vivax malaria by highlighting best practices in currently published models and highlighting where further model development is required. We categorise P. vivax models according to whether a deterministic or agent-based approach was used. We provide an overview of the different strategies used to incorporate the parasite's biology, use of multiple scales (within-host and population-level), superinfection, immunity, and treatment interventions. In most of the published literature, the rationale for different modelling approaches was driven by the research question at hand. Some models focus on the parasites' complicated biology, while others incorporate simplified assumptions to avoid model complexity. Overall, the existing literature on mathematical models for P. vivax encompasses various aspects of the parasite's dynamics. We recommend that future research should focus on refining how key aspects of P. vivax dynamics are modelled, including spatial heterogeneity in exposure risk and heterogeneity in susceptibility to infection, the accumulation of hypnozoite variation, the interaction between P. falciparum and P. vivax, acquisition of immunity, and recovery under superinfection.
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Affiliation(s)
- Md Nurul Anwar
- School of Mathematics and Statistics, The University of Melbourne, Parkville, Australia
- Department of Mathematics, Bangabandhu Sheikh Mujibur Rahman Science and Technology University, Gopalganj, Bangladesh
| | - Lauren Smith
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - Angela Devine
- Division of Global and Tropical Health, Menzies School of Health Research, Charles Darwin University, Darwin, Australia
- Health Economics Unit, Centre for Health Policy, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Australia
| | - Somya Mehra
- School of Mathematics and Statistics, The University of Melbourne, Parkville, Australia
| | - Camelia R Walker
- School of Mathematics and Statistics, The University of Melbourne, Parkville, Australia
| | - Elizabeth Ivory
- School of Mathematics and Statistics, The University of Melbourne, Parkville, Australia
| | - Eamon Conway
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - Ivo Mueller
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - James M McCaw
- School of Mathematics and Statistics, The University of Melbourne, Parkville, Australia
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Australia
| | - Jennifer A Flegg
- School of Mathematics and Statistics, The University of Melbourne, Parkville, Australia
| | - Roslyn I Hickson
- School of Mathematics and Statistics, The University of Melbourne, Parkville, Australia
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, Australia
- Commonwealth Scientific and Industrial Research Organisation, Townsville, Australia
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Nekkab N, Obadia T, Monteiro WM, Lacerda MV, White M, Mueller I. Accelerating towards P. vivax elimination with a novel serological test-and-treat strategy: a modelling case study in Brazil. LANCET REGIONAL HEALTH. AMERICAS 2023; 22:100511. [PMID: 37250687 PMCID: PMC10209700 DOI: 10.1016/j.lana.2023.100511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 04/05/2023] [Accepted: 05/04/2023] [Indexed: 05/31/2023]
Abstract
Background Plasmodium vivax malaria is challenging to control and eliminate. Treatment with radical cure drugs fails to target the hidden asymptomatic and hypnozoite reservoirs in populations. PvSeroTAT, a novel serological test-and-treat intervention using a serological diagnostic to screen hypnozoite carriers for radical cure eligibility and treatment, could accelerate P. vivax elimination. Methods Using a previously developed mathematical model of P. vivax transmission adapted to the Brazilian context as a case study for implementation, we evaluate the public health impact of various deployment strategies of PvSeroTAT as a mass campaign. We compare relative reductions in prevalence, cases averted, glucose-6-phosphate dehydrogenase (G6PD) tests, and treatment doses of PvSeroTAT campaigns to strengthened case management alone or mass drug administration (MDA) campaigns across different settings. Findings Deploying a single round of PvSeroTAT with 80% coverage to treat cases with a high efficacy radical cure regimen with primaquine is predicted to reduce point population prevalence by 22.5% [95% UI: 20.2%-24.8%] in a peri-urban setting with high transmission and by 25.2% [95% UI: 9.6%-42.2%] in an occupational setting with moderate transmission. In the latter example, while a single PvSeroTAT achieves 9.2% less impact on prevalence and averts 300 less cases per 100,000 than a single MDA (25.2% [95% UI: 9.6%-42.2%] point prevalence reduction versus 34.4% [95% UI: 24.9%-44%]), PvSeroTAT requires 4.6 times less radical cure treatments and G6PD tests. Layering strengthened case management and deploying four rounds of PvSeroTAT six months apart is predicted to reduce point prevalence by a mean of 74.1% [95% UI: 61.3%-86.3%] or more in low transmission settings with less than 10 cases per 1000 population. Interpretation Modelling predicts that mass campaigns with PvSeroTAT are predicted to reduce P. vivax parasite prevalence across a range of transmission settings and require fewer resources than MDA. In combination with strengthened case management, mass campaigns of serological test-and-treat interventions can accelerate towards P. vivax elimination. Funding This project was funded in part by the Bill and Melinda Gates Foundation and the National Health and Medical Research Council.
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Affiliation(s)
- Narimane Nekkab
- Institut Pasteur, Université Paris Cité, G5 Épidémiologie et Analyse des Maladies Infectieuses, Paris, France
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Thomas Obadia
- Institut Pasteur, Université Paris Cité, G5 Épidémiologie et Analyse des Maladies Infectieuses, Paris, France
- Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics Hub, Paris, France
| | - Wuelton M. Monteiro
- Escola Superior de Ciências da Saúde, Universidade do Estado do Amazonas, Manaus, Brazil
- Diretoria de Ensino e Pesquisa, Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Manaus, Brazil
| | - Marcus V.G. Lacerda
- Diretoria de Ensino e Pesquisa, Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Manaus, Brazil
- Instituto Leônidas e Maria Deane, Fundação Oswaldo Cruz, Manaus, Brazil
| | - Michael White
- Institut Pasteur, Université Paris Cité, G5 Épidémiologie et Analyse des Maladies Infectieuses, Paris, France
| | - Ivo Mueller
- Population Health & Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Australia
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Stresman G, DePina AJ, Nelli L, Monteiro DDS, Leal SDV, Moreira AL, Furtado UD, Roka JCL, Neatherlin J, Gomes C, Tfeil AK, Lindblade KA. Factors related to human-vector contact that modify the likelihood of malaria transmission during a contained Plasmodium falciparum outbreak in Praia, Cabo Verde. FRONTIERS IN EPIDEMIOLOGY 2022; 2:1031230. [PMID: 38455281 PMCID: PMC10910924 DOI: 10.3389/fepid.2022.1031230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 11/10/2022] [Indexed: 03/09/2024]
Abstract
Background Determining the reproductive rate and how it varies over time and space (RT) provides important insight to understand transmission of a given disease and inform optimal strategies for controlling or eliminating it. Estimating RT for malaria is difficult partly due to the widespread use of interventions and immunity to disease masking incident infections. A malaria outbreak in Praia, Cabo Verde in 2017 provided a unique opportunity to estimate RT directly, providing a proxy for the intensity of vector-human contact and measure the impact of vector control measures. Methods Out of 442 confirmed malaria cases reported in 2017 in Praia, 321 (73%) were geolocated and informed this analysis. RT was calculated using the joint likelihood of transmission between two cases, based on the time (serial interval) and physical distance (spatial interval) between them. Log-linear regression was used to estimate factors associated with changes in RT, including the impact of vector control interventions. A geostatistical model was developed to highlight areas receptive to transmission where vector control activities could be focused in future to prevent or interrupt transmission. Results The RT from individual cases ranged between 0 and 11 with a median serial- and spatial-interval of 34 days [interquartile range (IQR): 17-52] and 1,347 m (IQR: 832-1,985 m), respectively. The number of households receiving indoor residual spraying (IRS) 4 weeks prior was associated with a reduction in RT by 0.84 [95% confidence interval (CI) 0.80-0.89; p-value <0.001] in the peak-and post-epidemic compared to the pre-epidemic period. Conclusions Identifying the effect of reduced human-vector contact through IRS is essential to determining optimal intervention strategies that modify the likelihood of malaria transmission and can inform optimal intervention strategies to accelerate time to elimination. The distance within which two cases are plausibly linked is important for the potential scale of any reactive interventions as well as classifying infections as imported or introduced and confirming malaria elimination.
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Affiliation(s)
- Gillian Stresman
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
- College of Public Health, University of South Florida, Tampa, FL, United States
| | | | - Luca Nelli
- School of Biodiversity, One Health, and Veterinary Medicine, University of Glasgow, Glasgow, United Kingdom
| | | | - Silvânia da Veiga Leal
- Laboratório de Entomologia Médica, Instituto Nacional de Saúde Pública, Praia, Cabo Verde
| | | | | | | | - John Neatherlin
- U.S. Centers for Disease Control and Prevention, Atlanta, GA, United States
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Tan AF, Sakam SSB, Rajahram G, William T, Abd Rachman Isnadi M, Daim S, Barber B, Kho S, Sutherland CJ, Anstey NM, Yerlikaya S, van Schalkwyk DA, Grigg MJ. Diagnostic accuracy and limit of detection of ten malaria parasite lactate dehydrogenase-based rapid tests for Plasmodium knowlesi and P. falciparum. Front Cell Infect Microbiol 2022; 12:1023219. [PMID: 36325471 PMCID: PMC9618705 DOI: 10.3389/fcimb.2022.1023219] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 09/26/2022] [Indexed: 11/21/2022] Open
Abstract
Background Plasmodium knowlesi causes zoonotic malaria across Southeast Asia. First-line diagnostic microscopy cannot reliably differentiate P. knowlesi from other human malaria species. Rapid diagnostic tests (RDTs) designed for P. falciparum and P. vivax are used routinely in P. knowlesi co-endemic areas despite potential cross-reactivity for species-specific antibody targets. Methods Ten RDTs were evaluated: nine to detect clinical P. knowlesi infections from Malaysia, and nine assessing limit of detection (LoD) for P. knowlesi (PkA1-H.1) and P. falciparum (Pf3D7) cultures. Targets included Plasmodium-genus parasite lactate dehydrogenase (pan-pLDH) and P. vivax (Pv)-pLDH. Results Samples were collected prior to antimalarial treatment from 127 patients with microscopy-positive PCR-confirmed P. knowlesi mono-infections. Median parasitaemia was 788/µL (IQR 247-5,565/µL). Pan-pLDH sensitivities ranged from 50.6% (95% CI 39.6–61.5) (SD BIOLINE) to 87.0% (95% CI 75.1–94.6) (First Response® and CareStart™ PAN) compared to reference PCR. Pv-pLDH RDTs detected P. knowlesi with up to 92.0% (95% CI 84.3-96.7%) sensitivity (Biocredit™). For parasite counts ≥200/µL, pan-pLDH (Standard Q) and Pv-pLDH RDTs exceeded 95% sensitivity. Specificity of RDTs against 26 PCR-confirmed negative controls was 100%. Sensitivity of six highest performing RDTs were not significantly different when comparing samples taken before and after (median 3 hours) antimalarial treatment. Parasite ring stages were present in 30% of pre-treatment samples, with ring stage proportions (mean 1.9%) demonstrating inverse correlation with test positivity of Biocredit™ and two CareStart™ RDTs. For cultured P. knowlesi, CareStart™ PAN demonstrated the lowest LoD at 25 parasites/µL; LoDs of other pan-pLDH ranged from 98 to >2000 parasites/µL. Pv-pLDH LoD for P. knowlesi was 49 parasites/µL. No false-positive results were observed in either P. falciparum-pLDH or histidine-rich-protein-2 channels. Conclusion Selected RDTs demonstrate sufficient performance for detection of major human malaria species including P. knowlesi in co-endemic areas where microscopy is not available, particularly for higher parasite counts, although cannot reliably differentiate among non-falciparum malaria.
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Affiliation(s)
- Angelica F. Tan
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, N T, Australia
- Infectious Diseases Society Kota Kinabalu Sabah – Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
- *Correspondence: Angelica F. Tan, ; Matthew J. Grigg,
| | - Sitti Saimah binti Sakam
- Infectious Diseases Society Kota Kinabalu Sabah – Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | - Giri S. Rajahram
- Infectious Diseases Society Kota Kinabalu Sabah – Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
- Clinical Research Centre, Queen Elizabeth Hospital, Ministry of Health, Kota Kinabalu, Sabah, Malaysia
- Department of Medicine, Queen Elizabeth Hospital II, Kota Kinabalu, Sabah, Malaysia
| | - Timothy William
- Infectious Diseases Society Kota Kinabalu Sabah – Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
- Clinical Research Centre, Queen Elizabeth Hospital, Ministry of Health, Kota Kinabalu, Sabah, Malaysia
| | | | - Sylvia Daim
- Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Bridget E. Barber
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, N T, Australia
- Clinical Malaria, Queensland Institute of Medical Research (QIMR) Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Steven Kho
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, N T, Australia
| | - Colin J. Sutherland
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Nicholas M. Anstey
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, N T, Australia
- Infectious Diseases Society Kota Kinabalu Sabah – Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | - Seda Yerlikaya
- Malaria and Fever, Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland
| | - Donelly A. van Schalkwyk
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Matthew J. Grigg
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, N T, Australia
- Infectious Diseases Society Kota Kinabalu Sabah – Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
- *Correspondence: Angelica F. Tan, ; Matthew J. Grigg,
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A framework for evaluating health system surveillance sensitivity to support public health decision-making for malaria elimination: a case study from Indonesia. BMC Infect Dis 2022; 22:619. [PMID: 35840923 PMCID: PMC9288013 DOI: 10.1186/s12879-022-07581-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 06/30/2022] [Indexed: 12/01/2022] Open
Abstract
Background The effectiveness of a surveillance system to detect infections in the population is paramount when confirming elimination. Estimating the sensitivity of a surveillance system requires identifying key steps in the care-seeking cascade, from initial infection to confirmed diagnosis, and quantifying the probability of appropriate action at each stage. Using malaria as an example, a framework was developed to estimate the sensitivity of key components of the malaria surveillance cascade.
Methods Parameters to quantify the sensitivity of the surveillance system were derived from monthly malaria case data over a period of 36 months and semi-quantitative surveys in 46 health facilities on Java Island, Indonesia. Parameters were informed by the collected empirical data and estimated by modelling the flow of an infected individual through the system using a Bayesian framework. A model-driven health system survey was designed to collect empirical data to inform parameter estimates in the surveillance cascade. Results Heterogeneity across health facilities was observed in the estimated probability of care-seeking (range = 0.01–0.21, mean ± sd = 0.09 ± 0.05) and testing for malaria (range = 0.00–1.00, mean ± sd = 0.16 ± 0.29). Care-seeking was higher at facilities regularly providing antimalarial drugs (Odds Ratio [OR] = 2.98, 95% Credible Intervals [CI]: 1.54–3.16). Predictably, the availability of functioning microscopy equipment was associated with increased odds of being tested for malaria (OR = 7.33, 95% CI = 20.61). Conclusions The methods for estimating facility-level malaria surveillance sensitivity presented here can help provide a benchmark for what constitutes a strong system. The proposed approach also enables programs to identify components of the health system that can be improved to strengthen surveillance and support public-health decision-making.
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Dasgupta RR, Mao W, Ogbuoji O. Addressing child health inequity through case management of under-five malaria in Nigeria: an extended cost-effectiveness analysis. Malar J 2022; 21:81. [PMID: 35264153 PMCID: PMC8905868 DOI: 10.1186/s12936-022-04113-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 03/02/2022] [Indexed: 11/27/2022] Open
Abstract
Background Under-five malaria in Nigeria is a leading cause of global child mortality, accounting for 95,000 annual child deaths. High out-of-pocket medical expenditure contributes to under-five malaria mortality by discouraging care-seeking and use of effective anti-malarials in the poorest households. The significant inequity in child health outcomes in Nigeria stresses the need to evaluate the outcomes of potential interventions across socioeconomic lines. Methods Using a decision tree model, an extended cost-effectiveness analysis was done to determine the effects of subsidies covering the direct and indirect costs of case management of under-five malaria in Nigeria. This analysis estimates the number of child deaths averted, out-of-pocket (OOP) expenditure averted, cases of catastrophic health expenditure (CHE) averted, and cost of implementation. An optimization analysis was also done to determine how to optimally allocate money across wealth groups using different combinations of interventions. Results Fully subsidizing direct medical, non-medical, and indirect costs could annually avert over 19,000 under-five deaths, 8600 cases of CHE, and US$187 million in OOP spending. Per US$1 million invested, this corresponds to an annual reduction of 76 under-five deaths, 34 cases of CHE, and over US$730,000 in OOP expenditure. Due to low initial treatment coverage in poorer socioeconomic groups, health and financial-risk protection benefits would be pro-poor, with the poorest 40% of Nigerians accounting for 72% of all deaths averted, 55% of all OOP expenditure averted, and 74% of all cases of CHE averted. Subsidies targeted to the poor would see greater benefits per dollar spent than broad, non-targeted subsidies. In an optimization scenario, the strategy of fully subsidizing direct medical costs would be dominated by a partial subsidy of direct medical costs as well as a full subsidy of direct medical, nonmedical, and indirect costs. Conclusion Subsidizing case management of under-five malaria for the poorest and most vulnerable would reduce illness-related impoverishment and child mortality in Nigeria while preserving limited financial resources. This study is an example of how focusing a targeted policy-intervention on a single, high-burden disease can yield large health and financial-risk protection benefits in a low and middle-income country context and address equity consideration in evidence-informed policymaking. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04113-w.
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Affiliation(s)
- Rishav Raj Dasgupta
- Trinity College of Arts and Sciences, Duke University, Durham, NC, USA. .,Center for Policy Impact in Global Health at Duke Global Health Institute, Durham, NC, USA.
| | - Wenhui Mao
- Center for Policy Impact in Global Health at Duke Global Health Institute, Durham, NC, USA
| | - Osondu Ogbuoji
- Center for Policy Impact in Global Health at Duke Global Health Institute, Durham, NC, USA. .,Duke Margolis Center for Health Policy, Durham, NC, USA.
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Mooney JP, DonVito SM, Lim R, Keith M, Pickles L, Maguire EA, Wagner-Gamble T, Oldfield T, Bermejo Pariente A, Ehimiyien AM, Philbey AA, Bottomley C, Riley EM, Thompson J. Intestinal inflammation and increased intestinal permeability in Plasmodium chabaudi AS infected mice. Wellcome Open Res 2022; 7:134. [PMID: 36408291 PMCID: PMC9647155 DOI: 10.12688/wellcomeopenres.17781.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2022] [Indexed: 11/20/2022] Open
Abstract
Background: Gastrointestinal symptoms are commonly associated with acute Plasmodium spp infection. Malaria-associated enteritis may provide an opportunity for enteric pathogens to breach the intestinal mucosa, resulting in life-threatening systemic infections. Methods: To investigate whether intestinal pathology also occurs during infection with a murine model of mild and resolving malaria, C57BL/6J mice were inoculated with recently mosquito-transmitted Plasmodium chabaudi AS. At schizogony, intestinal tissues were collected for quantification and localisation of immune mediators and malaria parasites, by PCR and immunohistochemistry. Inflammatory proteins were measured in plasma and faeces and intestinal permeability was assessed by FITC-dextran translocation after oral administration. Results: Parasitaemia peaked at approx. 1.5% at day 9 and resolved by day 14, with mice experiencing significant and transient anaemia but no weight loss. Plasma IFN-γ, TNF-α and IL10 were significantly elevated during peak infection and quantitative RT-PCR of the intestine revealed a significant increase in transcripts for ifng and cxcl10. Histological analysis revealed parasites within blood vessels of both the submucosa and intestinal villi and evidence of mild crypt hyperplasia. In faeces, concentrations of the inflammatory marker lactoferrin were significantly raised on days 9 and 11 and FITC-dextran was detected in plasma on days 7 to 14. At day 11, plasma FITC-dextran concentration was significantly positively correlated with peripheral parasitemia and faecal lactoferrin concentration. Conclusions: In summary, using a relevant, attenuated model of malaria, we have found that acute infection is associated with intestinal inflammation and increased intestinal permeability. This model can now be used to explore the mechanisms of parasite-induced intestinal inflammation and to assess the impact of increased intestinal permeability on translocation of enteropathogens.
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Affiliation(s)
- Jason P Mooney
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK
| | - Sophia M DonVito
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK
| | - Rivka Lim
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK
| | - Marianne Keith
- Division of Infection and Immunity, The Roslin Institute, University of Edinburgh, Edinburgh, EH25 9RG, UK
| | - Lia Pickles
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK
| | - Eleanor A Maguire
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK
| | - Tara Wagner-Gamble
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK
| | - Thomas Oldfield
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK
| | - Ana Bermejo Pariente
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK.,Editorial Team, F1000 Ltd., London, UK
| | - Ajoke M Ehimiyien
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK.,Department of Veterinary Medicine, Ahmadu Bello University, Zaria, Nigeria
| | - Adrian A Philbey
- Easter Bush Pathology, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom., Edinburgh, EH25 9RG, UK
| | - Christian Bottomley
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Eleanor M Riley
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK
| | - Joanne Thompson
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK
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Mooney JP, DonVito SM, Lim R, Keith M, Pickles L, Maguire EA, Wagner-Gamble T, Oldfield T, Bermejo Pariente A, Ehimiyein AM, Philbey AA, Bottomley C, Riley EM, Thompson J. Intestinal inflammation and increased intestinal permeability in Plasmodium chabaudi AS infected mice. Wellcome Open Res 2022; 7:134. [PMID: 36408291 PMCID: PMC9647155 DOI: 10.12688/wellcomeopenres.17781.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/15/2022] [Indexed: 11/20/2022] Open
Abstract
Background: Gastrointestinal symptoms are commonly associated with acute Plasmodium spp infection. Malaria-associated enteritis may provide an opportunity for enteric pathogens to breach the intestinal mucosa, resulting in life-threatening systemic infections. Methods: To investigate whether intestinal pathology also occurs during infection with a murine model of mild and resolving malaria, C57BL/6J mice were inoculated with recently mosquito-transmitted Plasmodium chabaudi AS. At schizogony, intestinal tissues were collected for quantification and localisation of immune mediators and malaria parasites, by PCR and immunohistochemistry. Inflammatory proteins were measured in plasma and faeces and intestinal permeability was assessed by FITC-dextran translocation after oral administration. Results: Parasitaemia peaked at approx. 1.5% at day 9 and resolved by day 14, with mice experiencing significant and transient anaemia but no weight loss. Plasma IFNγ, TNFα and IL10 were significantly elevated during peak infection and quantitative RT-PCR of the intestine revealed a significant increase in transcripts for ifng and cxcl10. Histological analysis revealed parasites within blood vessels of both the submucosa and intestinal villi and evidence of mild crypt hyperplasia. In faeces, concentrations of the inflammatory marker lactoferrin were significantly raised on days 9 and 11 and FITC-dextran was detected in plasma on days 7 to 14. At day 11, plasma FITC-dextran concentration was significantly positively correlated with peripheral parasitemia and faecal lactoferrin concentration. Conclusions: In summary, using a relevant, attenuated model of malaria, we have found that acute infection is associated with intestinal inflammation and increased intestinal permeability. This model can now be used to explore the mechanisms of parasite-induced intestinal inflammation and to assess the impact of increased intestinal permeability on translocation of enteropathogens.
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Affiliation(s)
- Jason P Mooney
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK
| | - Sophia M DonVito
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK
| | - Rivka Lim
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK
| | - Marianne Keith
- Division of Infection and Immunity, The Roslin Institute, University of Edinburgh, Edinburgh, EH25 9RG, UK
| | - Lia Pickles
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK
| | - Eleanor A Maguire
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK
| | - Tara Wagner-Gamble
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK
| | - Thomas Oldfield
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK
| | - Ana Bermejo Pariente
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK.,Editorial Team, F1000 Ltd., London, UK
| | - Ajoke M Ehimiyein
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK.,Department of Veterinary Medicine, Ahmadu Bello University, Zaria, Nigeria
| | - Adrian A Philbey
- Easter Bush Pathology, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom., Edinburgh, EH25 9RG, UK
| | - Christian Bottomley
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Eleanor M Riley
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK
| | - Joanne Thompson
- Institute of Immunology and Infection Research, University of Ediburgh, Edinburgh, Midlothian, EH93JT, UK
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9
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Hatherell HA, Simpson H, Baggaley RF, Hollingsworth TD, Pullan RL. Sustainable Surveillance of Neglected Tropical Diseases for the Post-Elimination Era. Clin Infect Dis 2021; 72:S210-S216. [PMID: 33977302 PMCID: PMC8201586 DOI: 10.1093/cid/ciab211] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The World Health Organization’s (WHO’s) 2030 road map for neglected tropical diseases (NTDs) emphasizes the importance of strengthened, institutionalized “post-elimination” surveillance. The required shift from disease-siloed, campaign-based programming to routine, integrated surveillance and response activities presents epidemiological, logistical, and financial challenges, yet practical guidance on implementation is lacking. Nationally representative survey programs, such as demographic and health surveys (DHS), may offer a platform for the integration of NTD surveillance within national health systems and health information systems. Here, we describe characteristics of DHS and other surveys conducted within the WHO Africa region in terms of frequency, target populations, and sample types and discuss applicability for post-validation and post-elimination surveillance. Maximizing utility depends not only on the availability of improved diagnostics but also on better understanding of the spatial and temporal dynamics of transmission at low prevalence. To this end, we outline priorities for obtaining additional data to better characterize optimal post-elimination surveillance platforms.
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Affiliation(s)
- Hollie-Ann Hatherell
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Hope Simpson
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Rebecca F Baggaley
- Department of Respiratory Sciences, University of Leicester, Leicester, United Kingdom
| | | | - Rachel L Pullan
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom
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10
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Prusty D, Gupta N, Upadhyay A, Dar A, Naik B, Kumar N, Prajapati VK. Asymptomatic malaria infection prevailing risks for human health and malaria elimination. INFECTION GENETICS AND EVOLUTION 2021; 93:104987. [PMID: 34216796 DOI: 10.1016/j.meegid.2021.104987] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 06/23/2021] [Accepted: 06/27/2021] [Indexed: 01/09/2023]
Abstract
There has been a consistent rise in malaria cases in the last few years. The existing malaria control measures are challenged by insecticide resistance in the mosquito vector, drug résistance in parasite populations, and asymptomatic malaria (ASM) in healthy individuals. The absence of apparent malaria symptoms and the presence of low parasitemia makes ASM a hidden reservoir for malaria transmission and an impediment in malaria elimination efforts. This review focuses on ASM in malaria-endemic countries and the past and present research trends from those geographical locations. The harmful impacts of asymptomatic malaria on human health and its contribution to disease transmission are highlighted. We discuss certain crucial genetic changes in the parasite and host immune response necessary for maintaining low parasitemia leading to long-term parasite survival in the host. Since the chronic health effects and the potential roles for disease transmission of ASM remain mostly unknown to significant populations, we offer proposals for developing general awareness. We also suggest advanced technology-based diagnostic methods, and treatment strategies to eliminate ASM.
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Affiliation(s)
- Dhaneswar Prusty
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer, 305817, Rajasthan, India.
| | - Nidhi Gupta
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer, 305817, Rajasthan, India
| | - Arun Upadhyay
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer, 305817, Rajasthan, India
| | - Ashraf Dar
- Department of Biochemistry, University of Kashmir, Hazaratbal, Srinagar 190006, Jammu and Kashmir, India
| | - Biswajit Naik
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer, 305817, Rajasthan, India
| | - Navin Kumar
- School of Biotechnology, Gautam Buddha University, Greater Noida, 201308, UP, India
| | - Vijay Kumar Prajapati
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer, 305817, Rajasthan, India
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11
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Kamau A, Mtanje G, Mataza C, Malla L, Bejon P, Snow RW. The relationship between facility-based malaria test positivity rate and community-based parasite prevalence. PLoS One 2020; 15:e0240058. [PMID: 33027313 PMCID: PMC7540858 DOI: 10.1371/journal.pone.0240058] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 09/17/2020] [Indexed: 02/06/2023] Open
Abstract
INTRODUCTION Malaria surveillance is a key pillar in the control of malaria in Africa. The value of using routinely collected data from health facilities to define malaria risk at community levels remains poorly defined. METHODS Four cross-sectional parasite prevalence surveys were undertaken among residents at 36 enumeration zones in Kilifi county on the Kenyan coast and temporally and spatially matched to fever surveillance at 6 health facilities serving the same communities over 12 months. The age-structured functional form of the relationship between test positivity rate (TPR) and community-based parasite prevalence (PR) was explored through the development of regression models fitted by alternating the linear, exponential and polynomial terms for PR. The predictive ranges of TPR were explored for PR endemicity risk groups of control programmatic value using cut-offs of low (PR <5%) and high (PR ≥ 30%) transmission intensity. RESULTS Among 28,134 febrile patients encountered for malaria diagnostic testing in the health facilities, 12,143 (43.2%: 95% CI: 42.6%, 43.7%) were positive. The overall community PR was 9.9% (95% CI: 9.2%, 10.7%) among 6,479 participants tested for malaria. The polynomial model was the best fitting model for the data that described the algebraic relationship between TPR and PR. In this setting, a TPR of ≥ 49% in all age groups corresponded to an age-standardized PR of ≥ 30%, while a TPR of < 40% corresponded to an age-standardized PR of < 5%. CONCLUSION A non-linear relationship was observed between the relative change in TPR and changes in the PR, which is likely to have important implications for malaria surveillance programs, especially at the extremes of transmission. However, larger, more spatially diverse data series using routinely collected TPR data matched to community-based infection prevalence data are required to explore the more practical implications of using TPR as a replacement for community PR.
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Affiliation(s)
- Alice Kamau
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
- * E-mail:
| | - Grace Mtanje
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Christine Mataza
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Ministry of Health, Kilifi County Government, Kilifi, Kenya
| | - Lucas Malla
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Philip Bejon
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Robert W. Snow
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
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12
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Ketema T, Bassat Q. Estimating the hidden magnitude of the malaria community burden. THE LANCET. INFECTIOUS DISEASES 2020; 20:881-883. [PMID: 32277909 DOI: 10.1016/s1473-3099(20)30142-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 11/26/2022]
Affiliation(s)
- Tsige Ketema
- Jimma University, Department of Biology, College of Natural Sciences, Jimma, Ethiopia
| | - Quique Bassat
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain; Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique; ICREA, Pg. Lluís Companys 23, Barcelona, Spain; Pediatric Infectious Diseases Unit, Pediatrics Department, Hospital Sant Joan de Déu (University of Barcelona), Barcelona, Spain; Consorcio de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain.
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