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Reis J, Spencer PS. An introduction to environmental neurotoxicology: Lessons from a clinical perspective. J Neurol Sci 2024; 463:123108. [PMID: 38991324 DOI: 10.1016/j.jns.2024.123108] [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: 06/19/2024] [Accepted: 06/20/2024] [Indexed: 07/13/2024]
Abstract
In 1992, the Committee on Neurotoxicology and Models for Assessing Risk of the National Academy of Sciences in Washington DC focused with a scientific perspective on the identification of substances with neurotoxic potential, studies of exposed populations, risk assessment, and biologic markers of disease. This Committee recommended: "all physicians should be trained to take a thorough occupational-exposure history and to be aware of other possible sources of toxic exposure". Although convened after several outbreaks of neurotoxic syndromes, clinical neurological considerations were lacking. After defining keys words, namely Environment, Neurotoxicology and Neurotoxicants, we present some demonstrative cases; e.g., the Epidemic Neuropathy in Cuba, Minamata disease, ALS/PDC on Guam, and the ALS hot spot in the French Alps. Always with a clinical and practical approach, we will then review the milieux that contain and convey potential neurotoxicants, the different exposure routes and the clinical presentations. Drawing lessons from clinical cases, we offer some thoughts concerning the future of Environmental Neurotoxicology (ENT). Pointing notably to the diffuse chemical contamination of ecosystems and living beings, including Homo sapiens, we question the real impact of agents with neurotoxic potential on the human brain, considering the effects, for example, of air pollution, endocrine disruptors and nanoparticles. Concern is expressed over the lack of knowledge of the non-monotonic kinetics of many of these chemicals, the major concern being related to mixtures and low-dose exposures, as well as the delayed appearance in clinical expression of prevalent neurodegenerative diseases.
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Affiliation(s)
- J Reis
- Department of Neurology, University Hospital of Strasbourg, 67000 Strasbourg, France; Association RISE, 67205 Oberhausbergen, France.
| | - P S Spencer
- Department of Neurology, School of Medicine, and Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR 97239, USA
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Brindle HE, Bastos LS, Christley R, Contamin L, Dang LH, Anh DD, French N, Griffiths M, Nadjm B, van Doorn HR, Thai PQ, Duong TN, Choisy M. The spatio-temporal distribution of acute encephalitis syndrome and its association with climate and landcover in Vietnam. BMC Infect Dis 2023; 23:403. [PMID: 37312047 PMCID: PMC10262680 DOI: 10.1186/s12879-023-08300-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 05/03/2023] [Indexed: 06/15/2023] Open
Abstract
BACKGROUND Acute encephalitis syndrome (AES) differs in its spatio-temporal distribution in Vietnam with the highest incidence seen during the summer months in the northern provinces. AES has multiple aetiologies, and the cause remains unknown in many cases. While vector-borne disease such as Japanese encephalitis and dengue virus and non-vector-borne diseases such as influenza and enterovirus show evidence of seasonality, associations with climate variables and the spatio-temporal distribution in Vietnam differs between these. The aim of this study was therefore to understand the spatio-temporal distribution of, and risk factors for AES in Vietnam to help hypothesise the aetiology. METHODS The number of monthly cases per province for AES, meningitis and diseases including dengue fever; influenza-like-illness (ILI); hand, foot, and mouth disease (HFMD); and Streptococcus suis were obtained from the General Department for Preventive Medicine (GDPM) from 1998-2016. Covariates including climate, normalized difference vegetation index (NDVI), elevation, the number of pigs, socio-demographics, JEV vaccination coverage and the number of hospitals were also collected. Spatio-temporal multivariable mixed-effects negative binomial Bayesian models with an outcome of the number of cases of AES, a combination of the covariates and harmonic terms to determine the magnitude of seasonality were developed. RESULTS The national monthly incidence of AES declined by 63.3% over the study period. However, incidence increased in some provinces, particularly in the Northwest region. In northern Vietnam, the incidence peaked in the summer months in contrast to the southern provinces where incidence remained relatively constant throughout the year. The incidence of meningitis, ILI and S. suis infection; temperature, relative humidity with no lag, NDVI at a lag of one month, and the number of pigs per 100,000 population were positively associated with the number of cases of AES in all models in which these covariates were included. CONCLUSIONS The positive correlation of AES with temperature and humidity suggest that a number of cases may be due to vector-borne diseases, suggesting a need to focus on vaccination campaigns. However, further surveillance and research are recommended to investigate other possible aetiologies such as S. suis or Orientia tsutsugamushi.
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Affiliation(s)
- Hannah E Brindle
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK.
- Oxford University Clinical Research Unit, Hanoi City, Vietnam.
| | - Leonardo S Bastos
- Scientific Computing Programme, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Robert Christley
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Lucie Contamin
- Institut de Recherche Pour Le Développement, Hanoi, Vietnam
| | - Le Hai Dang
- National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
| | - Dang Duc Anh
- National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
| | - Neil French
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Michael Griffiths
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Behzad Nadjm
- Oxford University Clinical Research Unit, Hanoi City, Vietnam
- MRC Unit The Gambia at the London, School of Hygiene & Tropical Medicine, Fajara, The Gambia
| | - H Rogier van Doorn
- Oxford University Clinical Research Unit, Hanoi City, Vietnam
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Pham Quang Thai
- National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
- School Preventive Medicine and Public Health, Hanoi Medical University, Hanoi, Vietnam
| | - Tran Nhu Duong
- National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
| | - Marc Choisy
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
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Singh AK, Jhalani M, Shahi SK, Christopher R, Kumar B, Das MK. Acute Encephalopathy in Children From Muzaffarpur, Bihar, India, and the Potential Role of Ambient Heat Stress-Induced Mitochondrial Dysfunction. Cureus 2023; 15:e37073. [PMID: 37153288 PMCID: PMC10156069 DOI: 10.7759/cureus.37073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2023] [Indexed: 04/05/2023] Open
Abstract
BACKGROUND Periodic outbreaks of acute encephalopathy in children have been reported from Muzaffarpur, Bihar, India. No infectious cause has been identified for this. This study presents the clinical and metabolic profile of children hospitalized with acute encephalopathy and the potential role of ambient heat stress. METHODS This cross-sectional study included children (<15 years) with acute encephalopathy admitted from April 4, 2019, to July 4, 2019. The clinical and laboratory investigations included infections, metabolic abnormalities, and muscle tissue analysis. The children who had metabolic derangements but no infectious cause were labeled as acute metabolic encephalopathy. The descriptive analysis summarized the clinical, laboratory, and histopathology findings, and their association with the ambient heat parameters was explored. RESULTS Out of the 450 children hospitalized (median age, four years), 94 (20.9%) died. Children had early morning onset (89%), seizures (99%), fever (82%), hypoglycemia at admission (64%), raised aminotransferases (60%), and high blood urea (66%). Blood lactate (50%), lactate dehydrogenase (84%), pyruvate (100%), ammonia (32%), and creatinine phosphokinase (69%) were raised. Viral marker tests were negative. The patients had abnormal metabolic markers like decreased blood-free carnitine, elevated blood acylcarnitines, and elevated urinary lactate, oxalate, maleate, adipate, and fatty acid metabolites. Blood carnitine and acylcarnitine levels normalized in 75% of the patients treated with carnitine and coenzyme-Q. Muscle tissues showed megamitochondria on electron microscopy and reduced respiratory enzyme complex-I activity. A significant correlation between the number of admissions and ambient heat indices was observed. CONCLUSIONS The findings suggest secondary mitochondrial dysfunction as a possible mechanism for acute encephalopathy in children from Muzaffarpur, Bihar, and ambient heat stress as a possible risk factor.
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Pommier JD, Gorman C, Crabol Y, Bleakley K, Sothy H, Santy K, Tran HTT, Nguyen LV, Bunnakea E, Hlaing CS, Aye AMM, Cappelle J, Herrant M, Piola P, Rosset B, Chevalier V, Tarantola A, Channa M, Honnorat J, Pinto AL, Rattanavong S, Vongsouvath M, Mayxay M, Phangmanixay S, Phongsavath K, Tin OS, Kyaw LL, Tin HH, Linn K, Tran TMH, Pérot P, Thuy NTT, Hien N, Phan PH, Buchy P, Dussart P, Laurent D, Eloit M, Dubot-Pérès A, Lortholary O, de Lamballerie X, Newton PN, Lecuit M. Childhood encephalitis in the Greater Mekong region (the SouthEast Asia Encephalitis Project): a multicentre prospective study. Lancet Glob Health 2022; 10:e989-e1002. [PMID: 35714649 PMCID: PMC9210261 DOI: 10.1016/s2214-109x(22)00174-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 03/09/2022] [Accepted: 03/23/2022] [Indexed: 12/11/2022]
Abstract
BACKGROUND Encephalitis is a worldwide public health issue, with a substantially high burden among children in southeast Asia. We aimed to determine the causes of encephalitis in children admitted to hospitals across the Greater Mekong region by implementing a comprehensive state-of-the-art diagnostic procedure harmonised across all centres, and identifying clinical characteristics related to patients' conditions. METHODS In this multicentre, observational, prospective study of childhood encephalitis, four referral hospitals in Cambodia, Vietnam, Laos, and Myanmar recruited children (aged 28 days to 16 years) who presented with altered mental status lasting more than 24 h and two of the following minor criteria: fever (within the 72 h before or after presentation), one or more generalised or partial seizures (excluding febrile seizures), a new-onset focal neurological deficit, cerebrospinal fluid (CSF) white blood cell count of 5 per mL or higher, or brain imaging (CT or MRI) suggestive of lesions of encephalitis. Comprehensive diagnostic procedures were harmonised across all centres, with first-line testing was done on samples taken at inclusion and results delivered within 24 h of inclusion for main treatable causes of disease and second-line testing was done thereafter for mostly non-treatable causes. An independent expert medical panel reviewed the charts and attribution of causes of all the included children. Using multivariate analyses, we assessed risk factors associated with unfavourable outcomes (ie, severe neurological sequelae and death) at discharge using data from baseline and day 2 after inclusion. This study is registered with ClinicalTrials.gov, NCT04089436, and is now complete. FINDINGS Between July 28, 2014, and Dec 31, 2017, 664 children with encephalitis were enrolled. Median age was 4·3 years (1·8-8·8), 295 (44%) children were female, and 369 (56%) were male. A confirmed or probable cause of encephalitis was identified in 425 (64%) patients: 216 (33%) of 664 cases were due to Japanese encephalitis virus, 27 (4%) were due to dengue virus, 26 (4%) were due to influenza virus, 24 (4%) were due to herpes simplex virus 1, 18 (3%) were due to Mycobacterium tuberculosis, 17 (3%) were due to Streptococcus pneumoniae, 17 (3%) were due to enterovirus A71, 74 (9%) were due to other pathogens, and six (1%) were due to autoimmune encephalitis. Diagnosis was made within 24 h of admission to hospital for 83 (13%) of 664 children. 119 (18%) children had treatable conditions and 276 (42%) had conditions that could have been preventable by vaccination. At time of discharge, 153 (23%) of 664 children had severe neurological sequelae and 83 (13%) had died. In multivariate analyses, risk factors for unfavourable outcome were diagnosis of M tuberculosis infection upon admission (odds ratio 3·23 [95% CI 1·04-10·03]), coma on day 2 (2·90 [1·78-4·72]), supplementary oxygen requirement (1·89 [1·25-2·86]), and more than 1 week duration between symptom onset and admission to hospital (3·03 [1·68-5·48]). At 1 year after inclusion, of 432 children who were discharged alive from hospital with follow-up data, 24 (5%) had died, 129 (30%) had neurological sequelae, and 279 (65%) had completely recovered. INTERPRETATION In southeast Asia, most causes of childhood encephalitis are either preventable or treatable, with Japanese encephalitis virus being the most common cause. We provide crucial information that could guide public health policy to improve diagnostic, vaccination, and early therapeutic guidelines on childhood encephalitis in the Greater Mekong region. FUNDING Institut Pasteur, Institut Pasteur International Network, Fondation Merieux, Aviesan Sud, INSERM, Wellcome Trust, Institut de Recherche pour le Développement (IRD), and Fondation Total.
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Affiliation(s)
- Jean David Pommier
- Epidemiology and Public Health Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia; Institut Pasteur, Biology of Infection Unit, Paris, France; Inserm U1117, Paris, France; Intensive Care Department, University Hospital of Guadeloupe, Guadeloupe, France
| | - Chris Gorman
- Virology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Yoann Crabol
- Epidemiology and Public Health Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Kevin Bleakley
- Université Paris-Saclay, CNRS, Inria, Laboratoire de Mathématiques d'Orsay, Orsay, France
| | - Heng Sothy
- Kantha Bopha IV Children's Hospital, Phnom Penh, Cambodia
| | - Ky Santy
- Kantha Bopha IV Children's Hospital, Phnom Penh, Cambodia
| | | | | | - Em Bunnakea
- Kantha Bopha IV Children's Hospital, Phnom Penh, Cambodia
| | | | | | - Julien Cappelle
- Epidemiology and Public Health Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia; French Agricultural Research Centre for International Development (CIRAD), Montpellier, France
| | - Magali Herrant
- International Department, Institut Pasteur, Paris, France
| | - Patrice Piola
- Epidemiology and Public Health Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Bruno Rosset
- French Agricultural Research Centre for International Development (CIRAD), Montpellier, France
| | - Veronique Chevalier
- Epidemiology and Public Health Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia; French Agricultural Research Centre for International Development (CIRAD), Montpellier, France
| | - Arnaud Tarantola
- Epidemiology and Public Health Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Mey Channa
- Virology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Jerome Honnorat
- French Reference Center for Paraneoplastic Neurological Syndromes and Autoi mmune Encephalitis, Hospices Civils de Lyon, Synatac Team, NeuroMyoGene Institute, Inserm U1217/CNRS UMR5310, Université de Lyon, Lyon, France
| | - Anne Laure Pinto
- French Reference Center for Paraneoplastic Neurological Syndromes and Autoi mmune Encephalitis, Hospices Civils de Lyon, Synatac Team, NeuroMyoGene Institute, Inserm U1217/CNRS UMR5310, Université de Lyon, Lyon, France
| | - Sayaphet Rattanavong
- Lao-Oxford-Mahosot Hospital, Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
| | - Manivanh Vongsouvath
- Lao-Oxford-Mahosot Hospital, Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
| | - Mayfong Mayxay
- Lao-Oxford-Mahosot Hospital, Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos; Unité des Virus Émergents, Marseille, France
| | | | | | | | | | | | - Kyaw Linn
- Yangon Children's Hospital, Yangon, Myanmar
| | | | - Philippe Pérot
- Laboratory for Pathogen Discovery, Institut Pasteur, Paris, France
| | | | - Nguyen Hien
- National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
| | | | - Philippe Buchy
- Virology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Philippe Dussart
- Virology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Denis Laurent
- Kantha Bopha IV Children's Hospital, Phnom Penh, Cambodia
| | - Marc Eloit
- Laboratory for Pathogen Discovery, Institut Pasteur, Paris, France; Ecole Nationale Vétérinaire d'Alfort, Maisons-Alfort, France
| | - Audrey Dubot-Pérès
- Lao-Oxford-Mahosot Hospital, Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos; Unité des Virus Émergents, Marseille, France; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Churchill Hospital, Oxford, UK
| | - Olivier Lortholary
- Université Paris Cité, Department of Infectious Diseases and Tropical Medicine, Necker-Enfants Malades University Hospital, Institut Imagine, Assistance Publique-Hôpitaux de Paris, Paris, France; Institut Pasteur, CNRS, Molecular Mycology Unit, National Reference Center for Mycoses and Antifungals, UMR 2000, Paris, France
| | | | - Paul N Newton
- Lao-Oxford-Mahosot Hospital, Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Churchill Hospital, Oxford, UK
| | - Marc Lecuit
- Institut Pasteur, Biology of Infection Unit, Paris, France; Inserm U1117, Paris, France; Université Paris Cité, Department of Infectious Diseases and Tropical Medicine, Necker-Enfants Malades University Hospital, Institut Imagine, Assistance Publique-Hôpitaux de Paris, Paris, France.
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