Encephalitis and meningitis in Western Africa: a scoping review of pathogens

History and Current State of Neurosurgery in the Gambia

BACKGROUND

Despite global efforts to improve surgical care access, many low- and middle-income countries, especially in neurosurgery, face significant shortages. The Gambia exemplifies this, with only 1 fully qualified neurosurgeon serving its population of 2.5 million people. This scarcity results in higher morbidity and mortality.

OBJECTIVE

We aim to document the history and current state of neurosurgery in the Gambia to raise awareness and promote neurosurgery development.

METHODS

The study reviews the Gambia's health care system, infrastructure, neurosurgical history, workforce, disease burden, and progress, with information derived from reference sources as well as author experience and interviews with key partners in Gambian health care.

RESULTS

Neurosurgery in the Gambia began in the 1970s, facing constraints due to competing health care demands. Significant progress occurred much later in the early 2010s, marked by the initiation of Banjul Neuro Missions and the establishment of a dedicated neurosurgery unit. We report significant progress with neurosurgical interventions in the past few years showcasing the unit's dedication to advancing neurosurgical care in the Gambia. However, challenges persist, including a lack of trained neurosurgeons, equipment shortages such as ventilators and diagnostic imaging. Financial barriers for patients, particularly related to the costs of computer tomography scans, pose significant hurdles, impacting the timely diagnosis and intervention for neurological conditions.

CONCLUSIONS

Neurosurgery in the Gambia is progressing, but challenges like equipment scarcity hinder further progress. We emphasize the need for addressing cost barriers, improving infrastructure, and fostering research. Engaging the government and international collaborations are vital for sustained development in Gambian neurosurgery.

Contribution of CNS and extra-CNS infections to neurodegeneration: a narrative review

Central nervous system infections have been suggested as a possible cause for neurodegenerative diseases, particularly sporadic cases. They trigger neuroinflammation which is considered integrally involved in neurodegenerative processes. In this review, we will look at data linking a variety of viral, bacterial, fungal, and protozoan infections to Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis and unspecified dementia. This narrative review aims to bring together a broad range of data currently supporting the involvement of central nervous system infections in the development of neurodegenerative diseases. The idea that no single pathogen or pathogen group is responsible for neurodegenerative diseases will be discussed. Instead, we suggest that a wide range of susceptibility factors may make individuals differentially vulnerable to different infectious pathogens and subsequent pathologies.

Clinical epidemiology, determinants, and outcomes of viral encephalitis in Ghana; a cross-sectional study

Viral encephalitis is a rare, yet severe neurological disorder. It poses a significant public health threat due to its high morbidity and mortality. Despite the disproportionate burden of the disease in impoverished African countries, the true extent of the problem remains elusive due to the scarcity of accurate diagnostic methods. The absence of timely and effective diagnostic tools, particularly Real-time Polymerase Chain Reaction, has led to misguided treatment, and an underestimation of the disease burden in Ghana. We conducted a prospective cross-sectional study to determine the viral aetiologies of encephalitis among patients presenting to a major referral hospital in Ghana from May 2019 and August 2022. The study aimed at providing a comprehensive information on the clinical epidemiology, and outcomes of viral encephalitis in Ghana. Clinical samples were collected from patients presenting with signs and symptoms of encephalitis and tested for viral agents using real-time polymerase chain reaction. We assessed the clinical epidemiology, risk factors and outcome of individuals using descriptive and logistic regression analysis. Seventy-seven (77) patients were enrolled unto the study. The participants frequently presented with fever (85.7%), seizures (80.5%), lethargy (64.9%) and headache (50.6%). Viruses were detected in 40.3% of the study participants in either cerebrospinal fluid, rectal or oral swab samples. The most frequently detected viruses were cytomegalovirus (48.4%), enteroviruses (38.7%) and HSV (29.0%). Twenty-one (27.3%) of the patients died while on hospital admission. Gender (OR = 5.70 (1.536-1.172), p = 0.01), and negative polymerase chain reaction test results were identified as significant factors associated with death. Antiviral treatment increased the chance of survival of viral encephalitis patients by 21.8%. Our results validate the crucial role of molecular tools as essential for the rapid diagnosis of viral encephalitis, enabling effective treatment and improved patient outcomes. This study contributes valuable epidemiological and clinical insight into viral encephalitis in Ghana.

Epidemiology and Transmission Dynamics of Viral Encephalitides in West Africa

Encephalitis is an inflammation of the brain, often caused by an autoimmune reaction, or in most cases because of a direct viral, bacterial, or parasitic infection. Viral encephalitides (VE) presents a significant public health concern globally, especially in West Africa. There are more than five hundred known arthropod-borne viruses (arboviruses), with over a hundred of them identified to cause encephalitic diseases in humans and animals, giving rise to a tremendous burden of the diseases and socioeconomic strains in tropical and subtropical regions worldwide. Despite their importance, few effective preventive and control measures in the form of vaccines and therapies are available, and when they are, their use is limited. These limitations are largely hinged on the paucity of information about the molecular epidemiology and transmission patterns of VE in West Africa. Here, we reviewed the transmission dynamics, molecular epidemiology, and the ecological drivers of VE in West Africa. Collectively, timely and accurate interventions are essential for encephalitic viral disease control. Moreover, the integrated health system approach, combining surveillance, vaccination, vector control, and community engagement, could be effective in preventing viral encephalitis globally.

Surveillance of Viral Encephalitis in the Context of COVID-19: A One-Year Observational Study among Hospitalized Patients in Dakar, Senegal

The burden of encephalitis and its associated viral etiology is poorly described in Africa. Moreover, neurological manifestations of COVID-19 are increasingly reported in many countries, but less so in Africa. Our prospective study aimed to characterize the main viral etiologies of patients hospitalized for encephalitis in two hospitals in Dakar. From January to December 2021, all adult patients that met the inclusion criteria for clinical infectious encephalitis were enrolled. Cerebrospinal fluids, blood, and nasopharyngeal swabs were taken and tested for 27 viruses. During the study period, 122 patients were enrolled. Viral etiology was confirmed or probable in 27 patients (22.1%), with SARS-CoV-2 (n = 8), HSV-1 (n = 7), HHV-7 (n = 5), and EBV (n = 4) being the most detected viruses. Age groups 40–49 was more likely to be positive for at least one virus with an odds ratio of 7.7. The mortality was high among infected patients, with 11 (41%) deaths notified during hospitalization. Interestingly, SARS-CoV-2 was the most prevalent virus in hospitalized patients presenting with encephalitis. Our results reveal the crucial need to establish a country-wide surveillance of encephalitis in Senegal to estimate the burden of this disease in our population and implement strategies to improve care and reduce mortality.

Global magnitude of encephalitis burden and its evolving pattern over the past 30 years

OBJECTIVE

We aimed to estimate the spatiotemporal patterns of the encephalitis burden along with its attributable risk factors at the national, regional, and global levels, which may be helpful in guiding targeted prevention and treatment programs.

METHODS

Based on available data sources, the incidence, mortality, and disability-adjusted life years (DALYs) of encephalitis in 204 countries and regions from 1990 to 2019 were reconstructed by the Global Burden of Disease Study 2019 using the Cause of Death Ensemble model, spatiotemporal Gaussian process regression, and DisMod-MR 2.1. We conducted a systematic analysis on the epidemiological characteristics of encephalitis in detail by gender, region, and age over the past three decades.

RESULTS

Globally, 1,444,720 incident cases, 89,900 deaths, and 4.80 million DALYs related to encephalitis were estimated in 2019. The age-standardized incidence rate and age-standardized mortality rate (ASMR) decreased from 23.17 and 2.18 to 19.33 and 1.19 per 100,000 person-years over the past 30 years, respectively. However, beginning in 2011-2013, the burden of encephalitis has shown an inflection point, with a further decline of the ASRs ceasing. Lower socio-demographic index (SDI) regions in South Asia, Western and Eastern Sub-Saharan Africa had the highest burden of encephalitis in 2019. During the past three decades, most countries of South Asia achieved significant control of the burden. In contrast, developed countries with a higher SDI have shown a notable increase in ASMR and age-standardized DALYs rate. Children and older adults have always been high-risk groups for encephalitis.

CONCLUSION

Although the global burden of encephalitis has decreased in the past 30 years, a further decline stopped from 2011-2013. The diverse burden in different regions calls for differentiated management, and the persistent high burden in some low-SDI regions and the increased burden in developed countries with higher SDIs deserve more attention.

ABBREVIATIONS

ASDR: age-standardized DALY rate, ASIR: age-standardized incidence rate, ASMR: age-standardized mortality rate, ASR: age-standardized rate, CI: confidence interval, DALY: disability-adjusted life-year, EAPC: estimated annual percentage change, GBD: Global Burden of Disease Study, HAP: household air pollution from solid fuels, HSE: herpes simplex encephalitis, HSV: herpes simplex virus, ICD: International Classification of Diseases, JE: Japanese encephalitis, PCR: polymerase chain reaction, SDI: socio-demographic index, TBE: tick-borne encephalitis, UI: uncertainty interval.

The Influence of Virus Infection on Microglia and Accelerated Brain Aging

Microglia are the resident immune cells of the central nervous system contributing substantially to health and disease. There is increasing evidence that inflammatory microglia may induce or accelerate brain aging, by interfering with physiological repair and remodeling processes. Many viral infections affect the brain and interfere with microglia functions, including human immune deficiency virus, flaviviruses, SARS-CoV-2, influenza, and human herpes viruses. Especially chronic viral infections causing low-grade neuroinflammation may contribute to brain aging. This review elucidates the potential role of various neurotropic viruses in microglia-driven neurocognitive deficiencies and possibly accelerated brain aging.