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Background. Knowledge of central nervous system (CNS) opportunistic infections (OIs) among people living with human immunodeficiency virus (HIV) in sub-Saharan Africa is limited. Methods. We analyzed 1 cerebrospinal fluid (CSF) sample from each of 331 HIV-infected adults with symptoms suggestive of CNS OI at a tertiary care center in Zambia. We used pathogen-specific primers to detect DNA from JC virus (JCV), varicella zoster virus (VZV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus (HSV) types 1 and 2, Mycobacterium tuberculosis, and Toxoplasma gondii via real-time polymerase chain reaction (PCR). Results. The patients' median CD4 + T-cell count was 89 cells/μL (interquartile range, 38–191 cells/μL). Of 331 CSF samples, 189 (57.1%) had at least 1 pathogen. PCR detected DNA from EBV in 91 (27.5%) patients, M. tuberculosis in 48 (14.5%), JCV in 20 (6.0%), CMV in 20 (6.0%), VZV in 13 (3.9%), HSV-1 in 5 (1.5%), and HSV-2 and T. gondii in none. Fungal and bacteriological studies showed Cryptococcus in 64 (19.5%) patients, pneumococcus in 8 (2.4%), and meningococcus in 2 (0.6%). Multiple pathogens were found in 68 of 189 (36.0%) samples. One hundred seventeen of 331 (35.3%) inpatients died during their hospitalization. Men were older than women (median, 37 vs 34 years; P = .01), more recently diagnosed with HIV (median, 30 vs 63 days; P = .03), and tended to have a higher mortality rate (40.2% vs 30.2%; P = .07). Conclusions. CNS OIs are frequent, potentially treatable complications of AIDS in Zambia. Multiple pathogens often coexist in CSF. EBV is the most prevalent CNS organism in isolation and in coinfection. Whether it is associated with CNS disease or a marker of inflammation requires further investigation. More comprehensive testing for CNS pathogens could improve treatment and patient outcomes in Zambia.

The elevation of neopterin in cerebrospinal fluid (CSF) has been reported in several neuroinflammatory disorders. However, it is not expected that neopterin alone can discriminate among different neuroinflammatory etiologies. We conducted an observational retrospective and case–control study to analyze the CSF biomarkers neopterin, total proteins, and leukocytes in a large cohort of pediatric patients with neuroinflammatory disorders. CSF samples from 277 subjects were included and classified into four groups: Viral meningoencephalitis, bacterial meningitis, acquired immune-mediated disorders, and patients with no-immune diseases (control group). CSF neopterin was analyzed with high-performance liquid chromatography. Microbiological diagnosis included bacterial CSF cultures and several specific real-time polymerase chain reactions. Molecular testing for multiple respiratory pathogens was also included. Antibodies against neuronal and glial proteins were tested. Canonical discriminant analysis of the three biomarkers was conducted to establish the best discriminant functions for the classification of the different clinical groups. Model validation was done by biomarker analyses in a new cohort of 95 pediatric patients. CSF neopterin displayed the highest values in the viral and bacterial infection groups. By applying canonical discriminant analysis, it was possible to classify the patients into the different groups. Validation analyses displayed good results for neuropediatric patients with no-immune diseases and for viral meningitis patients, followed by the other groups. This study provides initial evidence of a more efficient approach to promote the timely classification of patients with viral and bacterial infections and acquired autoimmune disorders. Through canonical equations, we have validated a new tool that aids in the early and differential diagnosis of these neuroinflammatory conditions.

The viral-inflammatory hypothesis of Alzheimer’s disease offers a new paradigm, yet interventions like antivirals and vaccination present a paradox that challenge therapeutic development. This perspective examines the critical research gap concerning cerebrospinal fluid (CSF) synaptic biomarkers in immunomodulatory therapy trials. Following decades of partially successful amyloid-centric trials, focus has shifted to upstream triggers including viral infections like Herpes Simplex Virus Type 1, Varicella Zoster Virus, and Severe Acute Respiratory Syndrome Coronavirus 2. While large observational and quasi-experimental studies suggest antivirals and vaccines reduce long-term dementia risk, the first major antiviral randomized controlled trial (Valacyclovir for Alzheimer’s Disease) was negative. This perspective posits that this paradox arises from a fundamental flaw in trial design: the absence of synaptic integrity biomarkers. Synaptic loss, not amyloid or tau burden, is the strongest correlate of cognitive decline. Therefore, CSF synaptic protein biomarkers such as the prognostic YWHAG: NPTX2 ratio, postsynaptic Neurogranin (Ng), and presynaptic Growth-Associated Protein 43 (GAP-43) are the most clinically relevant endpoints. The paradoxical trial results may arise from omitting these synaptic measures, creating a mechanistic “black box” obscuring their true biological effects. A strategic framework is proposed, centered on the mandatory inclusion of CSF synaptic biomarkers and relevant co-pathology markers like TAR DNA-Binding Protein 43 (TDP-43; a proteinopathy linked to viral triggers) in all antiviral and vaccine trials. This approach is critical to resolve existing paradoxes, elucidate mechanisms of neuroprotection, and accelerate developing effective therapies that preserve synaptic integrity to prevent and treat dementia.

Although the CNS is in part protected from peripheral insults by the blood–brain barrier and the blood‐cerebrospinal fluid barrier, a number of human viruses gain access to the brain, replicate within this organ, or sustain latent infection. The efficacy of antiviral drugs towards the cerebral viral load is often limited as both blood–brain interfaces impede their cerebral distribution. For polar compounds, the major factor restricting their entry lies in the tight junctions that occlude the paracellular pathway across these barriers. For compounds with more favourable lipid solubility properties, CNS penetration will be function of a number of physicochemical factors that include the degree of lipophilicity, size and ability to bind to protein or red blood cells, as well as other factors inherent to the vascular and choroidal systems, such as the local cerebral blood flow and the surface area available for exchange. In addition, influx and efflux transport systems, or metabolic processes active in both capillary endothelial cells and choroid plexus epithelial cells, can greatly change the bioavailability of a drug in one or several compartments of the CNS. The relative importance of these various factors with respect to the CNS delivery of the different classes of antiviral drugs is illustrated and discussed. Copyright © 2004 John Wiley & Sons, Ltd.

Objective:To determine the aetiologies and clinical characteristics of infants with fever and a bulging fontanelle.Design:The medical records of all febrile infants with a bulging fontanelle who underwent a lumbar puncture from January 2000 to February 2008 in Assaf Harofeh Medical Center, a university affiliated hospital in central Israel, were identified.Results:153 patients met the inclusion criteria. The male to female ratio was 100:53; age range was 3–11 months with a mean age of 5.6 (SD 1.8) months and a median age of 5 months. Cerebrospinal fluid pleocytosis was found in 42 cases (27.3%), including one case of bacterial meningitis (0.6%). Other leading diagnoses were aseptic meningitis (26.7%), upper respiratory tract infection (18.3%), viral disease not otherwise specified (15.6%), roseola infantum (8.5%) and acute otitis media (6.5%). Appearance on admission was described as good to excellent in 113 (73.8%) infants, none of whom had bacterial meningitis. 32 had aseptic meningitis and 17 had other bacterial disease (pneumonia, acute otitis media, pyelonephritis, bacteraemia, shigella or salmonella gastroenteritis). All the latter had, upon admission, symptoms, signs, laboratory tests or imaging studies suggesting a bacterial aetiology.Conclusions:In this large cohort, all infants who appeared well on admission and had normal clinical, laboratory and imaging studies had benign (non-bacterial) disease. In an infant who appears well and has no evidence of bacterial disease, it is reasonable to observe the infant and withhold lumbar puncture. Prospective studies should be carried out to confirm this approach.

This study examined children with an acute encephalopathy illness for evidence of viral infection, disordered blood–brain barrier function, intrathecal immunoglobulin synthesis, and interferon (IFN) production, and related their temporal occurrence to outcome. A prospective study of 22 children (13 males, 9 females; age range 1mo to 13y, median 2y 4mo), recorded clinical details, with serum and cerebrospinal fluid (CSF) analysis near presentation and then on convalescent specimens taken up to day 39 of the neurological illness. Outcome was assessed with standard scales between 18 months and 3 years after presentation. A history consistent with viral infection was given in 17 children but laboratory evidence of viral infection was found in only 7 (7/17). In 18 out of 21 children, an elevated CSF:serum albumin ratio indicative of impairment of the blood–CSF and blood–brain barriers was detected at some stage of the illness. In 14 of the 15 children with a raised immunoglobulin G index, and in 12 of the 14 children where the CSF was positive for oligoclonal bands, this was preceded by, or was observed at the same time as, an abnormal albumin ratio. Sixteen children (16/18) had elevated IFN-α levels in serum, or CSF, or in both. We conclude that these findings indicate an initial disruption of the blood–brain barrier followed by intrathecal antibody production by activated lymphocytes, clonally restricted to a few antigens. This is the first in vivo study to show this as an important pathogenetic mechanism of encephalitis in children. Poor outcome was associated with young age, a deteriorating electroencephalogram pattern from grade 1 to grade 2, and the degree of blood–brain barrier impairment, particularly when prolonged, but not with Glasgow Coma Scale score. The persistence of IFN-α was associated with a good prognosis.

Standard laboratory techniques, such as viral culture and serology, provide only circumstantial or retrospective evidence of viral infections of the central nervous system (CNS). We assessed the diagnostic accuracy of PCR of cerebrospinal fluid (CSF) in the diagnosis of viral infections of the CNS. We examined all the CSF samples that were received at our diagnostic virology laboratory between May, 1994, and May, 1996, by nested PCR for viruses associated with CNS infections in the UK. We collected clinical and laboratory data for 410 patients from Oxford city hospitals (the Oxford cohort) whose CSF was examined between May, 1994, and May, 1995. These patients were classified according to the likelihood of a viral infection of the CNS. We used stratified logistic regression analysis to identify the clinical factors independently associated with a positive PCR result. We calculated likelihood ratios to estimate the clinical usefulness of PCR amplification of CSF. We tested 2233 consecutive CSF samples from 2162 patients. A positive PCR result was obtained in 143 patients, including 22 from the Oxford cohort. Logistic regression analysis of the Oxford cohort showed that fever, a virus-specific rash, and a CSF white-cell count of 5/μL or more were independent predictors of a positive PCR result. The likelihood ratio for a definite diagnosis of viral infection of the CNS in a patient with a positive PCR result, relative to a negative PCR result, was 88·2 (95% CI 20·6–378). The likelihood ratio for a possible diagnosis of viral infection of the CNS in a patient with a negative PCR result, relative to a positive PCR result, was 0·10 (0·03–0·39). A patient with a positive PCR result was 88 times as likely to have a definite diagnosis of viral infection of the CNS as a patient with a negative PCR result. A negative PCR result can be used with moderate confidence to rule out a diagnosis of viral infection of the CNS. We believe that PCR will become the first-line diagnostic test for viral meningitis and encephalitis.

Objectives: The value of measurements of serum C-reactive protein (CRP) in differentiating central nervous system (CNS) infections of varying etiologies in the Philippines was investigated. Methods: A wide array of bacteriologic and virologic methods as well as computed tomography, typical clinical presentation, and autopsy were used for etiologic diagnosis. Results: Among 103 patients with CNS infection, etiology was identified in 60 (58%) cases. Bacteria were found in 19 (including 7 Streptococcus pneumoniae, 5 Haemophilus influenzae, 3 Neisseria meningitidis), tuberculosis in 4, viruses in 38 (including 20 coxsackievirus, 8 measles, 4 adenovirus, and 4 poliovirus infections), and brain abscess in 3 patients. C-reactive protein was elevated on admission in all 18 cases of bacterial meningitis tested, exceeding 50 mg/L in 17 (94%), and was not affected by prior antibacterial treatment. The mean CRP was significantly higher in the bacterial group than in the viral group (207 ± 111 mg/L vs. 39 ± 34 mg/L; P < 0.001). In the viral group one third had CRP above 50 mg/L. In patients with tuberculous meningitis, brain abscess, or cryptococcal meningitis, CRP was moderately to highly elevated. Conclusions: In the presence of a normal CRP concentration (below 10 mg/mL) acute bacterial meningitis is excluded even in a developing country setting and antimicrobial therapy is not warranted.

The HHV6 virus had not yet been identified, although it was known that roseola infantum was often associated with febrile convulsions in children less than 1 year old, when roseola had its peak incidence. 3 Today, the expansion of techniques of rapid viral diagnosis, including the polymerase chain reaction, might lead to recognition of more \"neurotropic\" viruses and further support the proposition that a febrile convulsion occurs when a child with a genetic predisposition is exposed to a systemic virus or bacterium at a susceptible stage in brain development.