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Vollmuth N, Sin J, Kim BJ. Host-microbe interactions at the blood-brain barrier through the lens of induced pluripotent stem cell-derived brain-like endothelial cells. mBio 2024; 15:e0286223. [PMID: 38193670 PMCID: PMC10865987 DOI: 10.1128/mbio.02862-23] [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] [Indexed: 01/10/2024] Open
Abstract
Microbe-induced meningoencephalitis/meningitis is a life-threatening infection of the central nervous system (CNS) that occurs when pathogens are able to cross the blood-brain barrier (BBB) and gain access to the CNS. The BBB consists of highly specialized brain endothelial cells that exhibit specific properties to allow tight regulation of CNS homeostasis and prevent pathogen crossing. However, during meningoencephalitis/meningitis, the BBB fails to protect the CNS. Modeling the BBB remains a challenge due to the specialized characteristics of these cells. In this review, we cover the induced pluripotent stem cell-derived, brain-like endothelial cell model during host-pathogen interaction, highlighting the strengths and recent work on various pathogens known to interact with the BBB. As stem cell technologies are becoming more prominent, the stem cell-derived, brain-like endothelial cell model has been able to reveal new insights in vitro, which remain challenging with other in vitro cell-based models consisting of primary human brain endothelial cells and immortalized human brain endothelial cell lines.
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Affiliation(s)
- Nadine Vollmuth
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, USA
| | - Jon Sin
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, USA
| | - Brandon J. Kim
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, USA
- Department of Microbiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
- Center for Convergent Biosciences and Medicine, University of Alabama, Tuscaloosa, Alabama, USA
- Alabama Life Research Institute, University of Alabama, Tuscaloosa, Alabama, USA
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2
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Türkün C, Gölgeli M, Atay FM. A mathematical interpretation for outbreaks of bacterial meningitis under the effect of time-dependent transmission parameters. NONLINEAR DYNAMICS 2023; 111:1-18. [PMID: 37361004 PMCID: PMC10235855 DOI: 10.1007/s11071-023-08577-6] [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: 02/21/2023] [Accepted: 05/08/2023] [Indexed: 06/28/2023]
Abstract
We consider a SIR-type compartmental model divided into two age classes to explain the seasonal exacerbations of bacterial meningitis, especially among children outside of the meningitis belt. We describe the seasonal forcing through time-dependent transmission parameters that may represent the outbreak of the meningitis cases after the annual pilgrimage period (Hajj) or uncontrolled inflows of irregular immigrants. We present and analyse a mathematical model with time-dependent transmission. We consider not only periodic functions in the analysis but also general non-periodic transmission processes. We show that the long-time average values of transmission functions can be used as a stability marker of the equilibrium. Furthermore, we interpret the basic reproduction number in case of time-dependent transmission functions. Numerical simulations support and help visualize the theoretical results.
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Affiliation(s)
- Can Türkün
- Department of Mathematics, TOBB University of Economics and Technology, Ankara, Turkey
- Present Address: Department of Industrial Engineering, Altınbaş University, Istanbul, Turkey
| | - Meltem Gölgeli
- Department of Mathematics, TOBB University of Economics and Technology, Ankara, Turkey
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Cutland CL, Peyrani P, Webber C, Newton R, Cutler M, Perez JL. A phase 3, randomized, controlled, open-label study to evaluate the persistence up to 5 years of 1 or 2 doses of meningococcal conjugate vaccine MenACWY-TT given with or without 13-valent pneumococcal conjugate vaccine in 12-14-month-old children. Vaccine 2023; 41:1153-1160. [PMID: 36621408 DOI: 10.1016/j.vaccine.2022.11.048] [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: 01/10/2022] [Revised: 10/28/2022] [Accepted: 11/20/2022] [Indexed: 01/07/2023]
Abstract
BACKGROUND Immunogenicity and safety up to 5 years after administration of 1 or 2 doses of quadrivalent meningococcal serogroup A, C, W, and Y tetanus toxoid conjugate vaccine (MenACWY-TT) given alone or with 13-valent pneumococcal conjugate vaccine (PCV13) in children was investigated. METHODS This phase 3 study randomized healthy 12-24-month-olds to MenACWY-TT at Month 0 (ACWY1d), MenACWY-TT at Months 0 and 2 (ACWY2d), MenACWY-TT and PCV13 at Month 0 (Co-Ad), or PCV13 at Month 0 and MenACWY-TT at Month 2 (PCV13/ACWY). Immune responses 1, 3, and 5 years after primary vaccination were evaluated with serum bactericidal activity using rabbit complement (rSBA) titers ≥ 1:8 and geometric mean titers (GMTs). Evaluation of serious adverse events up to 5 years after primary vaccination are reported. RESULTS Of the 802 children randomized in the study, 619 completed the study through Year 5. Immune responses after vaccination declined over time but were higher 5 years after vaccination compared with levels before vaccination. At Year 5, the percentages of children with rSBA titers ≥ 1:8 across all serogroups were 20.5 %-58.6 %, 28.4 %-65.8 %, 23.9 %-52.8 %, and 19.4 %-55.8 % in the ACWY1d, ACWY2d, Co-Ad, and PCV13/ACWY groups, respectively. Comparable antibody persistence at Year 5 was observed for participants receiving 1 or 2 doses of MenACWY-TT, although GMTs were elevated in those who received 2 versus 1 dose. The percentage of children with protective antibody titers at Year 5 was similar in participants who received PCV13 and MenACWY-TT compared with that observed for participants who only received 1 or 2 MenACWY-TT doses. No new safety concerns were identified during the study period. CONCLUSION Antibody responses persisted in the majority of children up to 5 years after primary vaccination with MenACWY-TT administered in a 1- or 2-dose regimen with or without PCV13, with no new safety concerns identified. CLINICALTRIALS gov Identifier NCT01939158; EudraCT number 2013-001083-28.
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Affiliation(s)
- Clare L Cutland
- African Leadership in Vaccinology Expertise Unit (Alive), Johannesburg, South Africa; Department of Science and Technology National Research Foundation, Vaccine Preventable Diseases, Johannesburg, South Africa; Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Paula Peyrani
- Medical Development/Clinical and Scientific Affairs, Pfizer Inc, Collegeville, PA, USA
| | - Chris Webber
- Vaccine Research and Development, Pfizer, Hurley, Berkshire, UK.
| | - Ryan Newton
- Vaccine Research and Development, Pfizer, Hurley, Berkshire, UK
| | - Mark Cutler
- Vaccine Research and Development, Pfizer Inc, Pearl River, NY, USA
| | - John L Perez
- Vaccine Research and Development, Pfizer Inc, Collegeville, PA, USA
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4
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Mazamay S, Guégan JF, Diallo N, Bompangue D, Bokabo E, Muyembe JJ, Taty N, Vita TP, Broutin H. An overview of bacterial meningitis epidemics in Africa from 1928 to 2018 with a focus on epidemics "outside-the-belt". BMC Infect Dis 2021; 21:1027. [PMID: 34592937 PMCID: PMC8485505 DOI: 10.1186/s12879-021-06724-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 08/10/2021] [Indexed: 11/10/2022] Open
Abstract
Background Bacterial meningitis occurs worldwide but Africa remains the most affected continent, especially in the "Meningitis belt" that extends from Senegal to Ethiopia. Three main bacteria are responsible for causing bacterial meningitis, i.e., N. meningitidis (Nm), S. pneumoniae and H. influenzae type b. Among Nm, serogroup A used to be responsible for up to 80 to 85% of meningococcal meningitis cases in Africa. Since 2000, other Nm serogroups including W, X and C have also been responsible for causing epidemics. This overview aims to describe the main patterns of meningitis disease cases and pathogens from 1928 to 2018 in Africa with a special focus on disease conditions “out-of-the-belt” area that is still usually unexplored. Based on basic spatio-temporal methods, and a 90-years database of reported suspected meningitis cases and death from the World Health Organization, we used both geographic information system and spatio-temporal statistics to identify the major localizations of meningitis epidemics over this period in Africa. Results Bacterial meningitis extends today outside its historical limits of the meningitis belt. Since the introduction of MenAfrivac vaccine in 2010, there has been a dramatic decrease in NmA cases while other pathogen species and Nm variants including NmW, NmC and Streptococcus pneumoniae have become more prevalent reflecting a greater diversity of bacterial strains causing meningitis epidemics in Africa today. Conclusion Bacterial meningitis remains a major public health problem in Africa today. Formerly concentrated in the region of the meningitis belt with Sub-Saharan and Sudanian environmental conditions, the disease extends now outside these historical limits to reach more forested regions in the central parts of the continent. With global environmental changes and massive vaccination targeting a unique serogroup, an epidemiological transition of bacterial meningitis is ongoing, requiring both a better consideration of the etiological nature of the responsible agents and of their proximal and distal determinants. Supplementary Information The online version contains supplementary material available at 10.1186/s12879-021-06724-1.
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Affiliation(s)
- Serge Mazamay
- Département de Microbiologie, Faculté de Médecine, Université de Kinshasa, Kinshasa, Democratic Republic of Congo. .,MIVEGEC, Université de Montpellier, IRD, CNRS, 911 avenue Agropolis, BP 64501, 34394, Montpellier Cedex 5, France.
| | - Jean-François Guégan
- MIVEGEC, Université de Montpellier, IRD, CNRS, 911 avenue Agropolis, BP 64501, 34394, Montpellier Cedex 5, France.,ASTRE, INRAE, Cirad, Université de Montpellier, Campus international de Baillarguet, 34398, Montpellier Cedex 5, France
| | - Neby Diallo
- Département de Microbiologie, Faculté de Médecine, Université de Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Didier Bompangue
- Département de Microbiologie, Faculté de Médecine, Université de Kinshasa, Kinshasa, Democratic Republic of Congo.,Chrono-Environnement, UMR CNRS 6249 Université de Franche-Comté, Besançon, France
| | - Eric Bokabo
- Département de Microbiologie, Faculté de Médecine, Université de Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Jean-Jacques Muyembe
- Département de Microbiologie, Faculté de Médecine, Université de Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Nadège Taty
- Département de Microbiologie, Faculté de Médecine, Université de Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Tonton Paul Vita
- Département de Microbiologie, Faculté de Médecine, Université de Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Hélène Broutin
- MIVEGEC, Université de Montpellier, IRD, CNRS, 911 avenue Agropolis, BP 64501, 34394, Montpellier Cedex 5, France.,Département de Parasitologie-Mycologie, Faculté de Médecine, Université Cheikh Anta Diop (UCAD), Dakar, Sénégal.,Centre de Recherche en Ecologie et Evolution de la Santé (CREES), Montpellier, France
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5
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Mazamay S, Bompangue D, Guégan JF, Muyembe JJ, Raoul F, Broutin H. Understanding the spatio-temporal dynamics of meningitis epidemics outside the belt: the case of the Democratic Republic of Congo (DRC). BMC Infect Dis 2020; 20:291. [PMID: 32312246 PMCID: PMC7168871 DOI: 10.1186/s12879-020-04996-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 03/27/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Bacterial meningitis remains a major threat for the population of the meningitis belt. Between 2004 and 2009, in the countries of this belt, more than 200,000 people were infected with a 10% mortality rate. However, for almost 20 years, important meningitis epidemics are also reported outside this belt. Research is still very poorly developed in this part of the word like in the Democratic Republic of Congo (DRC), which experiences recurrent epidemics. This article describes for the first time the spatio-temporal patterns of meningitis cases and epidemics in DRC, in order to provide new insights for surveillance and control measures. METHODS Based on weekly suspected cases of meningitis (2000-2012), we used time-series analyses to explore the spatio-temporal dynamics of the disease. We also used both geographic information systems and geostatistics to identify spatial clusters of cases. Both using conventional statistics and the Cleveland's algorithm for decomposition into general trend, seasonal and residuals, we searched for the existence of seasonality. RESULTS We observed a low rate of biological confirmation of cases (11%) using soluble antigens search, culture and PCR. The main strains found are Streptococcus pneumoniae, Haemophilus influenzae and Neisseria meningitidis (A and C) serogroups. We identified 8 distinct spatial clusters, located in the northeastern and southeastern part of DRC, and in the capital city province, Kinshasa. A low seasonal trend was observed with higher incidence and attack rate of meningitis during the dry season, with a high heterogeneity in seasonal patterns occurring across the different districts and regions of DRC. CONCLUSION Despite challenges related to completeness of data reporting, meningitis dynamics shows weak seasonality in DRC. This tends to suggest that climatic, environmental factors might be less preponderant in shaping seasonal patterns in central Africa. The characterization of 8 distinct clusters of meningitis could be used for a better sentinel meningitis surveillance and optimization of vaccine strategy in DRC. Improving biological monitoring of suspected cases should be a priority for future eco-epidemiological studies to better understand the emergence and spread of meningitis pathogens, and the potential ecological, environmental drivers of this disease.
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Affiliation(s)
- Serge Mazamay
- Département de Microbiologie, Faculté de Médecine, Université de Kinshasa, Kinshasa, Democratic Republic of Congo
- MIVEGEC, UMR IRD CNRS UM, 911 avenue Agropolis, BP 64501, 34394 Montpellier Cedex 5, France
| | - Didier Bompangue
- Département de Microbiologie, Faculté de Médecine, Université de Kinshasa, Kinshasa, Democratic Republic of Congo
- UMR CNRS 6249 Chrono-Environnement, Besançon, France
| | - Jean-François Guégan
- MIVEGEC, UMR IRD CNRS UM, 911 avenue Agropolis, BP 64501, 34394 Montpellier Cedex 5, France
- ASTRE UMR INRAE Cirad UM, Campus International de Baillarguet, 34398 Montpellier 722 Cedex 5, France
| | - Jean-Jacques Muyembe
- Département de Microbiologie, Faculté de Médecine, Université de Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Francis Raoul
- UMR CNRS 6249 Chrono-Environnement, Besançon, France
| | - Hélène Broutin
- MIVEGEC, UMR IRD CNRS UM, 911 avenue Agropolis, BP 64501, 34394 Montpellier Cedex 5, France
- Département de Parasitologie-Mycologie, Faculté de Médecine, Université Cheikh Anta Diop (UCAD), Dakar, Senegal
- CREES (Centre de Recherche en Ecologie et Evolution de la Santé), Montpellier, France
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6
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Abdullahi Baba I, Ibrahim Olamilekan L, Yusuf A, Baleanu D. Analysis of meningitis model: A case study of northern Nigeria. AIMS BIOENGINEERING 2020. [DOI: 10.3934/bioeng.2020016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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7
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Mathematical Modelling of Bacterial Meningitis Transmission Dynamics with Control Measures. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2018; 2018:2657461. [PMID: 29780431 PMCID: PMC5892307 DOI: 10.1155/2018/2657461] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Accepted: 01/04/2018] [Indexed: 12/03/2022]
Abstract
Vaccination and treatment are the most effective ways of controlling the transmission of most infectious diseases. While vaccination helps susceptible individuals to build either a long-term immunity or short-term immunity, treatment reduces the number of disease-induced deaths and the number of infectious individuals in a community/nation. In this paper, a nonlinear deterministic model with time-dependent controls has been proposed to describe the dynamics of bacterial meningitis in a population. The model is shown to exhibit a unique globally asymptotically stable disease-free equilibrium ℰ0, when the effective reproduction number ℛVT ≤ 1, and a globally asymptotically stable endemic equilibrium ℰ1, when ℛVT > 1; and it exhibits a transcritical bifurcation at ℛVT = 1. Carriers have been shown (by Tornado plot) to have a higher chance of spreading the infection than those with clinical symptoms who will sometimes be bound to bed during the acute phase of the infection. In order to find the best strategy for minimizing the number of carriers and ill individuals and the cost of control implementation, an optimal control problem is set up by defining a Lagrangian function L to be minimized subject to the proposed model. Numerical simulation of the optimal problem demonstrates that the best strategy to control bacterial meningitis is to combine vaccination with other interventions (such as treatment and public health education). Additionally, this research suggests that stakeholders should press hard for the production of existing/new vaccines and antibiotics and their disbursement to areas that are most affected by bacterial meningitis, especially Sub-Saharan Africa; furthermore, individuals who live in communities where the environment is relatively warm (hot/moisture) are advised to go for vaccination against bacterial meningitis.
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8
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Yue RPH, Lee HF. Pre-industrial plague transmission is mediated by the synergistic effect of temperature and aridity index. BMC Infect Dis 2018; 18:134. [PMID: 29554882 PMCID: PMC5859406 DOI: 10.1186/s12879-018-3045-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Accepted: 03/13/2018] [Indexed: 01/14/2023] Open
Abstract
Background Although the linkage between climate change and plague transmission has been proposed in previous studies, the dominant approach has been to address the linkage with traditional statistical methods, while the possible non-linearity, non-stationarity and low frequency domain of the linkage has not been fully considered. We seek to address the above issue by investigating plague transmission in pre-industrial Europe (AD1347–1760) at both continental and country levels. Methods We apply Granger Causality Analysis to identify the casual relationship between climatic variables and plague outbreaks. We then apply Wavelet Analysis to explore the non-linear and non-stationary association between climate change and plague outbreaks. Results Our results show that 5-year lagged temperature and aridity index are the significant determinants of plague outbreaks in pre-industrial Europe. At the multi-decadal time scale, there are more frequent plague outbreaks in a cold and arid climate. The synergy of temperature and aridity index, rather than their individual effect, is more imperative in driving plague outbreaks, which is valid at both the continental and country levels. Conclusions Plague outbreaks come after cold and dry spells. The multi-decadal climate variability is imperative in driving the cycles of plague outbreaks in pre-industrial Europe. The lagged and multi-decadal effect of climate change on plague outbreaks may be attributable to the complexity of ecological, social, or climate systems, through which climate exerts its influence on plague dynamics. These findings may contribute to improve our understanding of the epidemiology of plague and other rodent-borne or flea-borne infectious diseases in human history. Electronic supplementary material The online version of this article (10.1186/s12879-018-3045-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ricci P H Yue
- Department of Geography, The University of Hong Kong, Pok Fu Lam, Hong Kong.
| | - Harry F Lee
- Department of Geography, The University of Hong Kong, Pok Fu Lam, Hong Kong. .,International Center for China Development Studies, The University of Hong Kong, Pok Fu Lam, Hong Kong.
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9
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Shaker R, Fayad D, Dbaibo G. Challenges and opportunities for meningococcal vaccination in the developing world. Hum Vaccin Immunother 2018; 14:1084-1097. [PMID: 29393729 DOI: 10.1080/21645515.2018.1434463] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Meningococcal disease continues to be a life threatening infection with high morbidity and mortality even in appropriately treated patients. Meningococcal vaccination plays a major role in the control of the disease; however, implementing vaccination remains problematic in the developing world. The objective of this review is to identify the challenges facing the use of meningococcal vaccines in the developing world in order to discuss the opportunities and available solutions to improve immunization in these countries. Inadequate epidemiologic information necessary to implement vaccination and financial challenges predominate. Multiple measures are needed to achieve the successful implementation of meningococcal conjugate vaccination programs that protect against circulating serogroups in developing countries including enhanced surveillance systems, financial support and aid through grants, product development partnerships that are the end result of effective collaboration and communication between different interdependent stakeholders to develop affordable vaccines, and demonstration of the cost-effectiveness of new meningococcal vaccines.
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Affiliation(s)
- Rouba Shaker
- a Department of Pediatrics and Adolescent Medicine, Division of Pediatric Infectious Diseases, and Center for Infectious Diseases Research , American University of Beirut Medical Center , Beirut , Lebanon
| | - Danielle Fayad
- a Department of Pediatrics and Adolescent Medicine, Division of Pediatric Infectious Diseases, and Center for Infectious Diseases Research , American University of Beirut Medical Center , Beirut , Lebanon
| | - Ghassan Dbaibo
- a Department of Pediatrics and Adolescent Medicine, Division of Pediatric Infectious Diseases, and Center for Infectious Diseases Research , American University of Beirut Medical Center , Beirut , Lebanon.,b Department of Biochemistry and Molecular Genetics , American University of Beirut , Beirut , Lebanon
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10
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Basta NE, Berthe A, Keita M, Onwuchekwa U, Tamboura B, Traore A, Hassan-King M, Manigart O, Nascimento M, Stuart JM, Trotter C, Blake J, Carr AD, Gray SJ, Newbold LS, Deng Y, Wolfson J, Halloran ME, Greenwood B, Borrow R, Sow SO. Meningococcal carriage within households in the African meningitis belt: A longitudinal pilot study. J Infect 2017; 76:140-148. [PMID: 29197599 PMCID: PMC5790055 DOI: 10.1016/j.jinf.2017.11.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 11/22/2017] [Indexed: 10/29/2022]
Abstract
OBJECTIVES Carriers of Neisseria meningitidis are a key source of transmission. In the African meningitis belt, where risk of meningococcal disease is highest, a greater understanding of meningococcal carriage dynamics is needed. METHODS We randomly selected an age-stratified sample of 400 residents from 116 households in Bamako, Mali, and collected pharyngeal swabs in May 2010. A month later, we enrolled all 202 residents of 20 of these households (6 with known carriers) and collected swabs monthly for 6 months prior to MenAfriVac vaccine introduction and returned 10 months later to collect swabs monthly for 3 months. We used standard bacteriological methods to identify N. meningitidis carriers and fit hidden Markov models to assess acquisition and clearance overall and by sex and age. RESULTS During the cross-sectional study 5.0% of individuals (20/400) were carriers. During the longitudinal study, 73 carriage events were identified from 1422 swabs analyzed, and 16.3% of individuals (33/202) were identified as carriers at least once. The majority of isolates were non-groupable; no serogroup A carriers were identified. CONCLUSIONS Our results suggest that the duration of carriage with any N. meningitidis averages 2.9 months and that males and children acquire and lose carriage more frequently in an urban setting in Mali. Our study informed the design of a larger study implemented in seven countries of the African meningitis belt.
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Affiliation(s)
- Nicole E Basta
- Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, Minnesota 55454, USA.
| | - Abdoulaye Berthe
- Centre pour les Vaccins en Developpement-Mali, Centre National d'Appui a la lutte contre la Maladie (CNAM) Ministère de la Santé, Ex-Institut Marchoux, BP 251, Bamako, Mali
| | - Mahamadou Keita
- Centre pour les Vaccins en Developpement-Mali, Centre National d'Appui a la lutte contre la Maladie (CNAM) Ministère de la Santé, Ex-Institut Marchoux, BP 251, Bamako, Mali
| | - Uma Onwuchekwa
- Centre pour les Vaccins en Developpement-Mali, Centre National d'Appui a la lutte contre la Maladie (CNAM) Ministère de la Santé, Ex-Institut Marchoux, BP 251, Bamako, Mali
| | - Boubou Tamboura
- Centre pour les Vaccins en Developpement-Mali, Centre National d'Appui a la lutte contre la Maladie (CNAM) Ministère de la Santé, Ex-Institut Marchoux, BP 251, Bamako, Mali
| | - Awa Traore
- Centre pour les Vaccins en Developpement-Mali, Centre National d'Appui a la lutte contre la Maladie (CNAM) Ministère de la Santé, Ex-Institut Marchoux, BP 251, Bamako, Mali
| | - Musa Hassan-King
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, United Kingdom
| | - Olivier Manigart
- Centre pour les Vaccins en Developpement-Mali, Centre National d'Appui a la lutte contre la Maladie (CNAM) Ministère de la Santé, Ex-Institut Marchoux, BP 251, Bamako, Mali; London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, United Kingdom
| | - Maria Nascimento
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, United Kingdom
| | - James M Stuart
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, United Kingdom
| | - Caroline Trotter
- Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES, United Kingdom
| | - Jayne Blake
- Meningococcal Reference Unit, Public Health England, Manchester Royal Infirmary, Manchester, M13 9WL, United Kingdom
| | - Anthony D Carr
- Meningococcal Reference Unit, Public Health England, Manchester Royal Infirmary, Manchester, M13 9WL, United Kingdom
| | - Stephen J Gray
- Meningococcal Reference Unit, Public Health England, Manchester Royal Infirmary, Manchester, M13 9WL, United Kingdom
| | - Lynne S Newbold
- Meningococcal Reference Unit, Public Health England, Manchester Royal Infirmary, Manchester, M13 9WL, United Kingdom
| | - Yangqing Deng
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, Minnesota 55454, USA
| | - Julian Wolfson
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, Minnesota 55454, USA
| | - M Elizabeth Halloran
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA; Department of Biostatistics, University of Washington, Seattle, Washington 98195, USA
| | - Brian Greenwood
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, United Kingdom
| | - Ray Borrow
- Meningococcal Reference Unit, Public Health England, Manchester Royal Infirmary, Manchester, M13 9WL, United Kingdom
| | - Samba O Sow
- Centre pour les Vaccins en Developpement-Mali, Centre National d'Appui a la lutte contre la Maladie (CNAM) Ministère de la Santé, Ex-Institut Marchoux, BP 251, Bamako, Mali
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Agier L, Martiny N, Thiongane O, Mueller JE, Paireau J, Watkins ER, Irving TJ, Koutangni T, Broutin H. Towards understanding the epidemiology of Neisseria meningitidis in the African meningitis belt: a multi-disciplinary overview. Int J Infect Dis 2016; 54:103-112. [PMID: 27826113 DOI: 10.1016/j.ijid.2016.10.032] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 10/21/2016] [Accepted: 10/29/2016] [Indexed: 01/22/2023] Open
Abstract
OBJECTIVES Neisseria meningitidis is the major cause of seasonal meningitis epidemics in the African meningitis belt. In the changing context of a reduction in incidence of serogroup A and an increase in incidence of serogroups W and C and of Streptococcus pneumoniae, a better understanding of the determinants driving the disease transmission dynamics remains crucial to improving bacterial meningitis control. METHODS The literature was searched to provide a multi-disciplinary overview of the determinants of meningitis transmission dynamics in the African meningitis belt. RESULTS Seasonal hyperendemicity is likely predominantly caused by increased invasion rates, sporadic localized epidemics by increased transmission rates, and larger pluri-annual epidemic waves by changing population immunity. Carriage likely involves competition for colonization and cross-immunity. The duration of immunity likely depends on the acquisition type. Major risk factors include dust and low humidity, and presumably human contact rates and co-infections; social studies highlighted environmental and dietary factors, with supernatural explanations. CONCLUSIONS Efforts should focus on implementing multi-country, longitudinal seroprevalence and epidemiological studies, validating immune markers of protection, and improving surveillance, including more systematic molecular characterizations of the bacteria. Integrating climate and social factors into disease control strategies represents a high priority for optimizing the public health response and anticipating the geographic evolution of the African meningitis belt.
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Affiliation(s)
- Lydiane Agier
- Combining Health Information, Computation and Statistics, Lancaster Medical School, Lancaster University, Lancaster, UK.
| | - Nadège Martiny
- Centre de Recherches de Climatologie (CRC), UMR 6282 CNRS Biogeosciences, Université de Bourgogne, Dijon, France
| | - Oumy Thiongane
- Institut de Recherche pour le Développement, UMR INTERTRYP IRD-CIRAD, Antenne IRD Bobo Dioulasso, Bobo, Burkina Faso
| | - Judith E Mueller
- EHESP French School of Public Health, Sorbonne Paris Cité, Rennes, France; Unité de l'Epidémiologie des Maladies Emergentes, Institut Pasteur, Paris, France
| | - Juliette Paireau
- Unité de l'Epidémiologie des Maladies Emergentes, Institut Pasteur, Paris, France; Department of Ecology and Evolutionary Biology, Princeton Environmental Institute, Princeton University, Princeton, New Jersey, USA
| | | | - Tom J Irving
- School of Social and Community Medicine, University of Bristol, Bristol, UK
| | - Thibaut Koutangni
- EHESP French School of Public Health, Sorbonne Paris Cité, Rennes, France; Unité de l'Epidémiologie des Maladies Emergentes, Institut Pasteur, Paris, France
| | - Hélène Broutin
- MIVEGEC, UMR 590CNRS/224IRD/UM, Montpellier, France; Service de Parasitologie-Mycologie, Faculté de Médecine, Université Cheikh Anta Diop, Fann, Dakar, Senegal
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12
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Diokhane AM, Jenkins GS, Manga N, Drame MS, Mbodji B. Linkages between observed, modeled Saharan dust loading and meningitis in Senegal during 2012 and 2013. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2016; 60:557-75. [PMID: 26296434 DOI: 10.1007/s00484-015-1051-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 08/08/2015] [Accepted: 08/09/2015] [Indexed: 05/24/2023]
Abstract
The Sahara desert transports large quantities of dust over the Sahelian region during the Northern Hemisphere winter and spring seasons (December-April). In episodic events, high dust concentrations are found at the surface, negatively impacting respiratory health. Bacterial meningitis in particular is known to affect populations that live in the Sahelian zones, which is otherwise known as the meningitis belt. During the winter and spring of 2012, suspected meningitis cases (SMCs) were with three times higher than in 2013. We show higher surface particular matter concentrations at Dakar, Senegal and elevated atmospheric dust loading in Senegal for the period of 1 January-31 May during 2012 relative to 2013. We analyze simulated particulate matter over Senegal from the Weather Research and Forecasting (WRF) model during 2012 and 2013. The results show higher simulated dust concentrations during the winter season of 2012 for Senegal. The WRF model correctly captures the large dust events from 1 January-31 March but has shown less skill during April and May for simulated dust concentrations. The results also show that the boundary conditions are the key feature for correctly simulating large dust events and initial conditions are less important.
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Affiliation(s)
- Aminata Mbow Diokhane
- Centre de Gestion de la Qualité de l'Air (CGQA), from the Direction de l'Environnement et des Etablissements Classés (DEEC), Dakar, Senegal
| | - Gregory S Jenkins
- Department of Physics and Astronomy, Howard University, Washington, DC, USA.
| | - Noel Manga
- Unité de formation et de recherche en Sciences de la santé (UFR-2S), Université Assane Seck Ziguinchor (UASZ), Ziguinchor, Senegal
| | - Mamadou S Drame
- Laboratory for Atmospheric-Oceanic Physics-Simeon Fongang (LPAO-SF), Cheikh Anta Diop University, Dakar, Senegal
| | - Boubacar Mbodji
- Centre de Gestion de la Qualité de l'Air (CGQA), from the Direction de l'Environnement et des Etablissements Classés (DEEC), Dakar, Senegal
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13
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Ferrari MJ, Fermon F, Nackers F, Llosa A, Magone C, Grais RF. Time is (still) of the essence: quantifying the impact of emergency meningitis vaccination response in Katsina State, Nigeria. Int Health 2014; 6:282-90. [PMID: 25193978 DOI: 10.1093/inthealth/ihu062] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND In 2009, a large meningitis A epidemic affected a broad region of northern Nigeria and southern Niger, resulting in more than 75 000 cases and 4000 deaths. In collaboration with state and federal agencies, Médecins Sans Frontières (MSF) intervened with a large-scale vaccination campaign using polysaccharide vaccine. Here the authors analyze the impact (cases averted) of the vaccination response as a function of the timing and coverage achieved. METHODS Phenomenological epidemic models were fitted to replicate meningitis surveillance data from the Nigerian Ministry of Health/WHO surveillance system and from reinforced surveillance conducted by MSF in both vaccinated and unvaccinated areas using a dynamic, state-space framework to account for under-reporting of cases. RESULTS The overall impact of the vaccination campaigns (reduction in meningitis cases) in Katsina State, northern Nigeria, ranged from 4% to 12%. At the local level, vaccination reduced cases by as much as 50% when campaigns were conducted early in the epidemic. CONCLUSIONS Reactive vaccination with polysaccharide vaccine during meningitis outbreaks can significantly reduce the case burden when conducted early and comprehensively. Introduction of the conjugate MenAfriVac vaccine has reduced rates of disease caused by serogroup A Neisseria meningitidis in the region. Despite this, reactive campaigns with polysaccharide vaccine remain a necessary and important tool for meningitis outbreak response.
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Affiliation(s)
- Matthew J Ferrari
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, PA 16802 USA
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14
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Codjoe SNA, Nabie VA. Climate change and cerebrospinal meningitis in the Ghanaian meningitis belt. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2014; 11:6923-39. [PMID: 25003550 PMCID: PMC4113853 DOI: 10.3390/ijerph110706923] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Revised: 06/19/2014] [Accepted: 06/24/2014] [Indexed: 11/16/2022]
Abstract
Cerebrospinal meningitis (CSM) is one of the infectious diseases likely to be affected by climate change. Although there are a few studies on the climate change-CSM nexus, none has considered perceptions of community members. However, understanding public perception in relation to a phenomenon is very significant for the design of effective communication and mitigation strategies as well as coping and adaptation strategies. This paper uses focus group discussions (FGDs) to fill this knowledge lacuna. Results show that although a few elderly participants ascribed fatal causes (disobedience to gods, ancestors, and evil spirits) to CSM infections during FGDs, majority of participants rightly linked CSM infections to dry, very hot and dusty conditions experienced during the dry season. Finally, community members use a suite of adaptation options to curb future CSM epidemics.
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Affiliation(s)
- Samuel Nii Ardey Codjoe
- Regional Institute for Population Studies, University of Ghana, P.O. Box LG 96, Legon, Ghana.
| | - Vivian Adams Nabie
- Regional Institute for Population Studies, University of Ghana, P.O. Box LG 96, Legon, Ghana.
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15
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García-Pando C, Thomson MC, Stanton MC, Diggle PJ, Hopson T, Pandya R, Miller RL, Hugonnet S. Meningitis and climate: from science to practice. ACTA ACUST UNITED AC 2014. [DOI: 10.1186/2194-6434-1-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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16
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Agier L, Broutin H, Bertherat E, Djingarey MH, Lingani C, Perea W, Hugonnet S. Timely detection of bacterial meningitis epidemics at district level: a study in three countries of the African Meningitis Belt. Trans R Soc Trop Med Hyg 2013; 107:30-6. [PMID: 23296695 DOI: 10.1093/trstmh/trs010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Bacterial meningitis is a major public health problem in the African 'Meningitis Belt', where recurrent unpredictable epidemics occur. Despite the introduction in 2010 of the conjugate A vaccine, the reactive strategy remains important for responding to epidemics caused by other bacteria and in areas not yet vaccinated. Review of weekly numbers of suspected cases in Niger, Mali and Burkina Faso identified spatial disparities in the annual patterns of meningitis, which suggested a more local way of defining epidemics and initiating a timely vaccination campaign. METHOD We defined an epidemic district-year as an excess of cases compared to the incidence previously experienced in the given district. Groups of similar districts in terms of seasonal patterns were identified by cluster analysis. We investigated a cluster-specific criterion of early epidemic onset to anticipate epidemic district-years. RESULTS These were encouraging, as epidemic district-years were fairly efficiently captured, with an average time gained of 2.5 weeks over the current strategy. CONCLUSION This early-onset criterion could help ensure timely implementation of vaccination campaigns without the need to modify the implemented surveillance system. The next step is to extend this study to other countries of the Meningitis Belt, and to explain the differences in seasonal patterns in the different clusters.
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Affiliation(s)
- Lydiane Agier
- Epidemic and Pandemic Alert and Response, World Health Organization, Geneva, Switzerland.
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17
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Agier L, Deroubaix A, Martiny N, Yaka P, Djibo A, Broutin H. Seasonality of meningitis in Africa and climate forcing: aerosols stand out. J R Soc Interface 2012; 10:20120814. [PMID: 23221989 DOI: 10.1098/rsif.2012.0814] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Bacterial meningitis is an ongoing threat for the population of the African Meningitis Belt, a region characterized by the highest incidence rates worldwide. The determinants of the disease dynamics are still poorly understood; nevertheless, it is often advocated that climate and mineral dust have a large impact. Over the last decade, several studies have investigated this relationship at a large scale. In this analysis, we scaled down to the district-level weekly scale (which is used for in-year response to emerging epidemics), and used wavelet and phase analysis methods to define and compare the time-varying periodicities of meningitis, climate and dust in Niger. We mostly focused on detecting time-lags between the signals that were consistent across districts. Results highlighted the special case of dust in comparison to wind, humidity or temperature: a strong similarity between districts is noticed in the evolution of the time-lags between the seasonal component of dust and meningitis. This result, together with the assumption of dust damaging the pharyngeal mucosa and easing bacterial invasion, reinforces our confidence in dust forcing on meningitis seasonality. Dust data should now be integrated in epidemiological and forecasting models to make them more realistic and usable in a public health perspective.
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Affiliation(s)
- L Agier
- Combining Health Information, Computation and Statistics, School of Health and Medicine, Lancaster University, Lancaster, UK.
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18
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A multi-state spatio-temporal Markov model for categorized incidence of meningitis in sub-Saharan Africa. Epidemiol Infect 2012; 141:1764-71. [PMID: 22995184 DOI: 10.1017/s0950268812001926] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Meningococcal meningitis is a major public health problem in the African Belt. Despite the obvious seasonality of epidemics, the factors driving them are still poorly understood. Here, we provide a first attempt to predict epidemics at the spatio-temporal scale required for in-year response, using a purely empirical approach. District-level weekly incidence rates for Niger (1986-2007) were discretized into latent, alert and epidemic states according to pre-specified epidemiological thresholds. We modelled the probabilities of transition between states, accounting for seasonality and spatio-temporal dependence. One-week-ahead predictions for entering the epidemic state were generated with specificity and negative predictive value >99%, sensitivity and positive predictive value >72%. On the annual scale, we predict the first entry of a district into the epidemic state with sensitivity 65∙0%, positive predictive value 49∙0%, and an average time gained of 4∙6 weeks. These results could inform decisions on preparatory actions.
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19
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Shibl A, Tufenkeji H, Khalil M, Memish Z. Consensus recommendation for meningococcal disease prevention in children and adolescents in the Middle East region. J Epidemiol Glob Health 2012; 2:23-30. [PMID: 23856395 PMCID: PMC7320358 DOI: 10.1016/j.jegh.2012.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Revised: 01/31/2012] [Accepted: 02/10/2012] [Indexed: 12/01/2022] Open
Abstract
Facing the availability of the new generation of quadrivalent meningococcal conjugate vaccines (Menveo®, Menactra® and others pending for license) and their recent implementation in Saudi Arabia, experts from 11 countries of the Middle East region met at a “Meningococcal Leadership Forum” (MLF), which took place in May 2010 in Dubai. The participants of the conference discussed the importance of introducing the concept of conjugate vaccines – especially for children and adolescents – and elaborated a consensus recommendation to support healthcare professionals and decision makers with their expertise. In experts’ opinion, conjugate vaccines are the best choice for the prevention of meningococcal disease caused by serogroups A, C, W-135 and Y. As quadrivalent meningococcal conjugate vaccines are registered and available in the Middle East region, they should replace plain polysaccharide vaccines and be integrated in pediatric and adolescent vaccination schedules, including infant vaccination concomitantly with basic EPI vaccines when licensed.
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Affiliation(s)
- Atef Shibl
- King Saud University, Riyadh, Saudi Arabia.
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20
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Paireau J, Girond F, Collard JM, Maïnassara HB, Jusot JF. Analysing spatio-temporal clustering of meningococcal meningitis outbreaks in Niger reveals opportunities for improved disease control. PLoS Negl Trop Dis 2012; 6:e1577. [PMID: 22448297 PMCID: PMC3308932 DOI: 10.1371/journal.pntd.0001577] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 02/09/2012] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Meningococcal meningitis is a major health problem in the "African Meningitis Belt" where recurrent epidemics occur during the hot, dry season. In Niger, a central country belonging to the Meningitis Belt, reported meningitis cases varied between 1,000 and 13,000 from 2003 to 2009, with a case-fatality rate of 5-15%. METHODOLOGY/PRINCIPAL FINDINGS In order to gain insight in the epidemiology of meningococcal meningitis in Niger and to improve control strategies, the emergence of the epidemics and their diffusion patterns at a fine spatial scale have been investigated. A statistical analysis of the spatio-temporal distribution of confirmed meningococcal meningitis cases was performed between 2002 and 2009, based on health centre catchment areas (HCCAs) as spatial units. Anselin's local Moran's I test for spatial autocorrelation and Kulldorff's spatial scan statistic were used to identify spatial and spatio-temporal clusters of cases. Spatial clusters were detected every year and most frequently occurred within nine southern districts. Clusters most often encompassed few HCCAs within a district, without expanding to the entire district. Besides, strong intra-district heterogeneity and inter-annual variability in the spatio-temporal epidemic patterns were observed. To further investigate the benefit of using a finer spatial scale for surveillance and disease control, we compared timeliness of epidemic detection at the HCCA level versus district level and showed that a decision based on threshold estimated at the HCCA level may lead to earlier detection of outbreaks. CONCLUSIONS/SIGNIFICANCE Our findings provide an evidence-based approach to improve control of meningitis in sub-Saharan Africa. First, they can assist public health authorities in Niger to better adjust allocation of resources (antibiotics, rapid diagnostic tests and medical staff). Then, this spatio-temporal analysis showed that surveillance at a finer spatial scale (HCCA) would be more efficient for public health response: outbreaks would be detected earlier and reactive vaccination would be better targeted.
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Affiliation(s)
- Juliette Paireau
- Unité d'Epidémiologie des Maladies Emergentes, Institut Pasteur, Paris, France.
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21
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Clones des souches de Neisseria meningitidis au Mali. Med Mal Infect 2011; 41:7-13. [DOI: 10.1016/j.medmal.2010.07.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2009] [Revised: 04/11/2010] [Accepted: 07/16/2010] [Indexed: 11/22/2022]
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22
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Ferrari MJ, Djibo A, Grais RF, Bharti N, Grenfell BT, Bjornstad ON. Rural-urban gradient in seasonal forcing of measles transmission in Niger. Proc Biol Sci 2010; 277:2775-82. [PMID: 20427338 DOI: 10.1098/rspb.2010.0536] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Seasonally driven cycles of incidence have been consistently observed for a range of directly transmitted pathogens. Though frequently observed, the mechanism of seasonality for directly transmitted human pathogens is rarely well understood. Despite significant annual variation in magnitude, measles outbreaks in Niger consistently begin in the dry season and decline at the onset of the seasonal rains. We estimate the seasonal fluctuation in measles transmission rates for the 38 districts and urban centres of Niger, from 11 years of weekly incidence reports. We show that transmission rates are consistently in anti-phase to the rainfall patterns across the country. The strength of the seasonal forcing of transmission is not correlated with the latitudinal rainfall gradient, as would be expected if transmission rates were determined purely by environmental conditions. Rather, seasonal forcing is correlated with the population size, with larger seasonal fluctuation in more populous, urban areas. This pattern is consistent with seasonal variation in human density and contact rates due to agricultural cycles. The stronger seasonality in large cities drives deep inter-epidemic troughs and results in frequent local extinction of measles, which contrasts starkly to the conventional observation that large cities, by virtue of their size, act as reservoirs of measles.
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Affiliation(s)
- Matthew J Ferrari
- The Center for Infectious Disease Dynamics, Department of Biology, The Pennsylvania State University, , University Park, PA 16802, USA.
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23
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Ford TE, Colwell RR, Rose JB, Morse SS, Rogers DJ, Yates TL. Using satellite images of environmental changes to predict infectious disease outbreaks. Emerg Infect Dis 2010. [PMID: 19788799 PMCID: PMC2819876 DOI: 10.3201/eid/1509.081334] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
A strong global satellite imaging system is essential for predicting outbreaks. Recent events clearly illustrate a continued vulnerability of large populations to infectious diseases, which is related to our changing human-constructed and natural environments. A single person with multidrug-resistant tuberculosis in 2007 provided a wake-up call to the United States and global public health infrastructure, as the health professionals and the public realized that today’s ease of airline travel can potentially expose hundreds of persons to an untreatable disease associated with an infectious agent. Ease of travel, population increase, population displacement, pollution, agricultural activity, changing socioeconomic structures, and international conflicts worldwide have each contributed to infectious disease events. Today, however, nothing is larger in scale, has more potential for long-term effects, and is more uncertain than the effects of climate change on infectious disease outbreaks, epidemics, and pandemics. We discuss advances in our ability to predict these events and, in particular, the critical role that satellite imaging could play in mounting an effective response.
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24
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Mosavi-Jarrahi A, Esteghamati A, Asgari F, Heidarnia M, Mousavi-Jarrahi Y, Goya M. Temporal analysis of the incidence of meningitis in the Tehran metropolitan area, 1999-2005. Popul Health Metr 2009; 7:19. [PMID: 20030846 PMCID: PMC2806853 DOI: 10.1186/1478-7954-7-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 12/23/2009] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVES The aim of this study was to describe the temporal determinants of meningitis incidence in the population living in the Tehran metropolis. METHODS All cases of meningitis reported to health districts throughout the Tehran metropolis from 1999 to 2005 were abstracted from patient files. Referral cases (patients who did not reside in the Tehran metropolis) were excluded. For each year, sex- and age-specific incidences were estimated. Temporality and its determinants were analyzed using Poisson regression. RESULTS Age-specific incidence is highest among males younger than 5 years of age at 10.2 cases per 100,000 population per year. The lowest incidence was among females aged 30 to 40 years at 0.72 cases per 100,000 population per year, with an overall male-to-female incidence ratio of 2.1. The temporal analysis showed seasonality, with a higher risk of meningitis in spring at a rate ratio of 1.31 with a 95% confidence interval (CI) of 1.20 to 1.41 and in autumn (rate ratio = 1.16, 95% CI 1.06, 1.27). For periodicity, we found a peak of occurrence around the years 2000 and 2003. CONCLUSION The epidemiology of meningitis in Iran follows similar patterns of age, sex, and seasonality distribution as found in other countries and populations.
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Affiliation(s)
- Alireza Mosavi-Jarrahi
- Department of Epidemiology, School of Public Health, Shaheed Beheshti University of Medical Sciences and Health Services, Tehran, I. R. of Iran
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25
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Joint reviews and inspections: Strategic forms of collaboration for strengthening the regulatory oversight of vaccine clinical trials in Africa. Vaccine 2009; 28:571-5. [DOI: 10.1016/j.vaccine.2009.09.117] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2009] [Accepted: 09/24/2009] [Indexed: 11/17/2022]
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26
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Palmgren H. Meningococcal disease and climate. Glob Health Action 2009; 2. [PMID: 20052424 PMCID: PMC2799239 DOI: 10.3402/gha.v2i0.2061] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 09/21/2009] [Accepted: 09/22/2009] [Indexed: 11/25/2022] Open
Affiliation(s)
- Helena Palmgren
- Department of Infectious Diseases, Umeå University, Umeå, Sweden
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27
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Ford TE, Colwell RR, Rose JB, Morse SS, Rogers DJ, Yates TL. Using satellite images of environmental changes to predict infectious disease outbreaks. Emerg Infect Dis 2009; 15:1341-6. [PMID: 19788799 PMCID: PMC2819876 DOI: 10.3201/eid1509.081334] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Recent events clearly illustrate a continued vulnerability of large populations to infectious diseases, which is related to our changing human-constructed and natural environments. A single person with multidrug-resistant tuberculosis in 2007 provided a wake-up call to the United States and global public health infrastructure, as the health professionals and the public realized that today's ease of airline travel can potentially expose hundreds of persons to an untreatable disease associated with an infectious agent. Ease of travel, population increase, population displacement, pollution, agricultural activity, changing socioeconomic structures, and international conflicts worldwide have each contributed to infectious disease events. Today, however, nothing is larger in scale, has more potential for long-term effects, and is more uncertain than the effects of climate change on infectious disease outbreaks, epidemics, and pandemics. We discuss advances in our ability to predict these events and, in particular, the critical role that satellite imaging could play in mounting an effective response.
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28
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Kinlin LM, Spain CV, Ng V, Johnson CC, White ANJ, Fisman DN. Environmental exposures and invasive meningococcal disease: an evaluation of effects on varying time scales. Am J Epidemiol 2009; 169:588-95. [PMID: 19164421 PMCID: PMC2640162 DOI: 10.1093/aje/kwn383] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Invasive meningococcal disease (IMD) is an important cause of meningitis and bacteremia worldwide. Seasonal variation in IMD incidence has long been recognized, but mechanisms responsible for this phenomenon remain poorly understood. The authors sought to evaluate the effect of environmental factors on IMD risk in Philadelphia, Pennsylvania, a major urban center. Associations between monthly weather patterns and IMD incidence were evaluated using multivariable Poisson regression models controlling for seasonal oscillation. Short-term weather effects were identified using a case-crossover approach. Both study designs control for seasonal factors that might otherwise confound the relation between environment and IMD. Incidence displayed significant wintertime seasonality (for oscillation, P < 0.001), and Poisson regression identified elevated monthly risk with increasing relative humidity (per 1% increase, incidence rate ratio = 1.04, 95% confidence interval: 1.004, 1.08). Case-crossover methods identified an inverse relation between ultraviolet B radiation index 1–4 days prior to onset and disease risk (odds ratio = 0.54, 95% confidence interval: 0.34, 0.85). Extended periods of high humidity and acute changes in ambient ultraviolet B radiation predict IMD occurrence in Philadelphia. The latter effect may be due to decreased pathogen survival or virulence and may explain the wintertime seasonality of IMD in temperate regions of North America.
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Affiliation(s)
- Laura M Kinlin
- Research Institute of the Hospital for Sick Children, Toronto, Ontario, Canada
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29
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Laboratory-based surveillance for patients with acute meningitis in Sudan, 2004–2005. Eur J Clin Microbiol Infect Dis 2008; 28:429-35. [DOI: 10.1007/s10096-008-0643-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Accepted: 10/03/2008] [Indexed: 10/21/2022]
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30
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Philippon S, Broutin H, Constantin de Magny G, Toure K, Diakite CH, Fourquet N, Courel MF, Sultan B, Guégan JF. Meningococcal meningitis in Mali: a long-term study of persistence and spread. Int J Infect Dis 2008; 13:103-9. [PMID: 18674942 DOI: 10.1016/j.ijid.2008.05.1223] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Revised: 04/29/2008] [Accepted: 05/01/2008] [Indexed: 10/21/2022] Open
Abstract
OBJECTIVES Meningococcal meningitis (MM) is still a huge threat in the African meningitis belt. To fight against epidemics, a strengthened health information system, based upon weekly collected data, was set up in Mali. We aimed to study the spatio-temporal dynamics of MM in this country between 1992 and 2003. METHODS We were first interested in the impact of population size on the disease persistence. We then used cross-correlation analysis to study the spread of the disease on three different spatial scales, i.e., inter-region (global) and inter-district and intra-district (local) levels. RESULTS We found no persistence of MM at district level in Mali during the whole of the study period. However, we found persistence on a nationwide scale after the 1997 big epidemics, as opposed to the 1992-1996 time periods. In terms of spread, two main regions seem to lead MM dynamics in Mali, even if on a local scale the 'cities-villages' diffusion pattern was not systematically observed. CONCLUSIONS This study improves knowledge on the spread and persistence of MM in Mali in recent years. It constitutes a first spatial study describing persistence and spread of MM in an African meningitis belt country. The next step should be the integration of vaccination and genetic variability data to clarify the route of spread of the disease in the human population.
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Yaka P, Sultan B, Broutin H, Janicot S, Philippon S, Fourquet N. Relationships between climate and year-to-year variability in meningitis outbreaks: a case study in Burkina Faso and Niger. Int J Health Geogr 2008; 7:34. [PMID: 18597686 PMCID: PMC2504476 DOI: 10.1186/1476-072x-7-34] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Accepted: 07/02/2008] [Indexed: 11/28/2022] Open
Abstract
Background Every year, West Africa is afflicted with Meningococcal Meningitis (MCM) disease outbreaks. Although the seasonal and spatial patterns of disease cases have been shown to be linked to climate, the mechanisms responsible for these patterns are still not well identified. Results A statistical analysis of annual incidence of MCM and climatic variables has been performed to highlight the relationships between climate and MCM for two highly afflicted countries: Niger and Burkina Faso. We found that disease resurgence in Niger and in Burkina Faso is likely to be partly controlled by the winter climate through enhanced Harmattan winds. Statistical models based only on climate indexes work well in Niger showing that 25% of the disease variance from year-to-year in this country can be explained by the winter climate but fail to represent accurately the disease dynamics in Burkina Faso. Conclusion This study is an exploratory attempt to predict meningitis incidence by using only climate information. Although it points out significant statistical results it also stresses the difficulty of relating climate to interannual variability in meningitis outbreaks.
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Affiliation(s)
- Pascal Yaka
- ProdiG, UMR 8586, 2 rue Valette, 75005, Paris, France.
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