[Etiological diagnostic methods and research progress of forest encephalitis].

Forest encephalitis is a natural focal disease transmitted through the bite of hard ticks, and its pathogen is the tick-borne encephalitis virus from the Flaviviridae family. The mortality rate of forest encephalitis is relatively high, making laboratory testing significant in diagnosing this disease. This article elaborates on the etiological diagnostic methods and recent research progress in forest encephalitis. Laboratory tests for forest encephalitis mainly include routine examinations, serological tests, virus isolation, and molecular biological testing. The detection of serum-specific IgM antibodies against the forest encephalitis virus is of great importance for early diagnosis, and specific IgG antibodies serve as a "gold standard" for differentiation from other diseases. Techniques such as enzyme-linked immunosorbent assay (ELISA) or indirect immunofluorescence assay for detecting specific IgM antibodies in serum and/or cerebrospinal fluid, the serum hemagglutination inhibition test or serum complement fixation test, and the double serum hemagglutination inhibition test or complement fixation test all contribute to the early diagnosis. The development of molecular testing methods is rapid, and techniques such as metabolomics, digital PCR, and matrix metalloproteinases are also applied in the early diagnosis of forest encephalitis.

Cell-binding IgM in CSF is distinctive of multiple sclerosis and targets the iron transporter SCARA5.

Intrathecal IgM production in multiple sclerosis is associated with a worse disease course. To investigate pathogenic relevance of autoreactive IgM in multiple sclerosis, CSF from two independent cohorts, including multiple sclerosis patients and controls, were screened for antibody binding to induced pluripotent stem cell-derived neurons and astrocytes, and a panel of CNS-related cell lines. IgM binding to a primitive neuro-ectodermal tumour cell line discriminated 10% of multiple sclerosis donors from controls. Transcriptomes of single IgM producing CSF B cells from patients with cell-binding IgM were sequenced and used to produce recombinant monoclonal antibodies for characterization and antigen identification. We produced five cell-binding recombinant IgM antibodies, of which one, cloned from an HLA-DR + plasma-like B cell, mediated antigen-dependent complement activation. Immunoprecipitation and mass spectrometry, and biochemical and transcriptome analysis of the target cells identified the iron transport scavenger protein SCARA5 as the antigen target of this antibody. Intrathecal injection of a SCARA5 antibody led to an increased T cell infiltration in an experimental autoimmune encephalomyelitis (EAE) model. CSF IgM might contribute to CNS inflammation in multiple sclerosis by binding to cell surface antigens like SCARA5 and activating complement, or by facilitating immune cell migration into the brain.

An algorithmic approach to identifying the aetiology of acute encephalitis syndrome in India: results of a 4-year enhanced surveillance study.

BACKGROUND: Annual outbreaks of acute encephalitis syndrome pose a major health burden in India. Although Japanese encephalitis virus (JEV) accounts for around 15% of reported cases, the aetiology of most cases remains unknown. We aimed to establish an enhanced surveillance network and to use a standardised diagnostic algorithm to conduct a systematic evaluation of acute encephalitis syndrome in India. METHODS: In this large-scale, systematic surveillance study in India, patients presenting with acute encephalitis syndrome (ie, acute onset of fever with altered mental status, seizure, or both) to any of the 18 participating hospitals across Uttar Pradesh, West Bengal, and Assam were evaluated for JEV (serum and cerebrospinal fluid [CSF] IgM ELISA) per standard of care. In enhanced surveillance, JEV IgM-negative specimens were additionally evaluated for scrub typhus, dengue virus, and West Nile virus by serum IgM ELISA, and for Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, dengue virus, herpes simplex virus, and enterovirus by CSF PCR across five referral laboratories. In 2017, chikungunya and Leptospira serum IgM by ELISA and Zika virus serum and CSF by PCR were also tested. FINDINGS: Of 10 107 patients with acute encephalitis syndrome enrolled in enhanced surveillance between Jan 1, 2014, and Dec 31, 2017, 5734 (57·8%) of 9917 participants with available data were male and 6179 (62·7%) of 9856 were children aged 15 years and younger. Among patients who provided a sample of either CSF or serum in enhanced surveillance, an aetiology was identified in 1921 (33·2%) of 5786 patients enrolled between 2014 and 2016 and in 1484 (34·3%) of 4321 patients enrolled in 2017. The most commonly identified aetiologies were JEV (1023 [17·7%] of 5786 patients), scrub typhus (645 [18·5%] of 3489), and dengue virus (161 [5·2%] of 3124). Among participants who provided both CSF and serum specimens, an aetiology was identified in 1446 (38·3%) of 3774 patients enrolled between 2014 and 2016 and in 936 (40·3%) of 2324 enrolled in 2017, representing a 3·1-times increase in the number of patients with acute encephalitis syndrome with an identified aetiology compared with standard care alone (299 [12·9%]; p<0·0001). INTERPRETATION: Implementation of a systematic diagnostic algorithm in an enhanced surveillance platform resulted in a 3·1-times increase in identification of the aetiology of acute encephalitis syndrome, besides JEV alone, and highlighted the importance of scrub typhus and dengue virus as important infectious aetiologies in India. These findings have prompted revision of the national testing guidelines for this syndrome across India. FUNDING: US Centers for Disease Control and Prevention.

The relationship between the laboratory diagnosis of Lyme neuroborreliosis and climate factors in Kalmar County Sweden - an overview between 2008 and 2019.

The purpose of this study was to describe the epidemiology of Lyme neuroborreliosis (LNB) in Kalmar County, in southern Sweden, between 2008 and 2019, and to analyse the relationship between the LNB incidence and climate factors. Data containing cerebrospinal fluid (CSF) cell counts and borrelia CSF/serum antibody index results was received from the departments of clinical chemistry and microbiology at Kalmar County hospital. For this study, we defined LNB as a case with a positive borrelia antibody CSF/serum index and CSF leukocytes > 5 × 106/L. Climate data including mean temperature, humidity and precipitation covering Kalmar County was collected from the Swedish Meteorological and Hydrological Institute. A total of 5051 paired serum-CSF samples from 4835 patients were investigated of which 251 laboratory LNB cases were found. The average annual LNB incidence in Kalmar County 2008-2019 was 8.8 cases per 100,000 inhabitants. Positive relationships were observed between mean temperature and LNB incidence (p < 0.001) as well as precipitation and LNB incidence (p = 0.003), both with a one calendar month delay. The results suggest an association between climate factors such as mean temperature and precipitation and LNB incidence, presumably through increased/decreased human-tick interactions. This calls for increased awareness of LNB in both the short perspective after periods of warmth and heavy precipitation as well as in a longer perspective in relation to possible climate change. Further studies with larger study groups, covering other geographical areas and over longer periods of time are needed to confirm these findings.

Assessing the presence of oligoclonal IgM bands as a prognostic biomarker of cognitive decline in the early stages of multiple sclerosis.

BACKGROUND: An association has been found between the presence of lipid-specific oligoclonal IgM bands (LS-OCMB) in cerebrospinal fluid and a more severe clinical multiple sclerosis course. OBJECTIVE: To investigate lipid-specific oligoclonal IgM bands as a prognostic biomarker of cognitive impairment in the early stages of multiple sclerosis. METHODS: Forty-four patients underwent neuropsychological assessment at baseline and 4 years. Cognitive performance at follow-up was compared adjusting by age, education, anxiety-depression, and baseline performance. RESULTS: LS-OCMB+ patients only performed worse for Long-Term Storage in the Selective Reminding Test (p = .018). CONCLUSION: There are no remarkable cognitive differences between LS-OCMB- and LS-OCMB+ patients in the early stages of MS.

Selected Biomarkers of Tick-Borne Encephalitis: A Review.

Tick-borne encephalitis (TBE) is an acute disease caused by the tick-borne encephalitis virus. Due to the viral nature of the condition, there is no effective causal treatment for full-blown disease. Current and nonspecific TBE treatments only relieve symptoms. Unfortunately, the first phase of TBE is characterized by flu-like symptoms, making diagnosis difficult during this period. The second phase is referred to as the neurological phase as it involves structures in the central nervous system-most commonly the meninges and, in more severe cases, the brain and the spinal cord. Therefore, it is important that early markers of TBE that will guide clinical decision-making and the choice of treatment are established. In this review, we performed an extensive search of literature reports relevant to biomarkers associated with TBE using the MEDLINE/PubMed database. We observed that apart from routinely determined specific immunoglobulins, free light chains may also be useful in the evaluation of intrathecal synthesis in the central nervous system (CNS) during TBEV infection. Moreover, selected metalloproteinases, chemokines, or cytokines appear to play an important role in the pathogenesis of TBE as a consequence of inflammatory reactions and recruitment of white blood cells into the CNS. Furthermore, we reported promising findings on tau protein or Toll-like receptors. It was also observed that some people may be predisposed to TBE. Therefore, to understand the role of selected tick-borne encephalitis biomarkers, we categorized these factors and discussed their potential application in the diagnosis, prognosis, monitoring, or management of TBE.

Prognostic utility of the IgM oligoclonal bands against myelin lipids in multiple sclerosis.

IgM oligoclonal bands (OCMBs) against myelin-specific lipids have been identified as a marker for poor prognosis in multiple sclerosis (MS). The aim is to examine the relation between lipid-specific OCMBs (LS-OCMBs) and the evolution of MS. An analytical, ambispective and individual-based study was conducted. We selected 116 patients, out of whom 95 had LS-OCMBs. The predominant lipid recognized was phosphatidylcholine. The positive gangliosides OCMB group reached better scores in the 9HPT, and the phosphatidylcholine, sphingolipids and phosphatidylethanolamine OCMB groups showed statistical differences in the magnetic resonance parameters. In conclusion: some LS-OCMBs showed statistically significant differences with functional or imaging tests.

Predicting Aggressive Multiple Sclerosis With Intrathecal IgM Synthesis Among Patients With a Clinically Isolated Syndrome.

OBJECTIVE: To determine the best method to measure intrathecal immunoglobulin (Ig) M synthesis (ITMS), a biomarker of worse prognosis in multiple sclerosis (MS). We compared the ability for predicting a poor evolution of 4 methods assessing ITMS (IgM oligoclonal bands [OCMBs], lipid-specific OCMBs [LS-OCMBs], Reibergram, and IgM index) in patients with a clinically isolated syndrome (CIS). METHODS: Prospective study with consecutive patients performed at a referral MS center. We used unadjusted and multivariate Cox regressions for predicting a second relapse, Expanded Disability Status Scale (EDSS) scores of 4 and 6, and development of secondary progressive MS (SPMS). RESULTS: A total of 193 patients were included, with a median (interquartile range) age of 31 (25-38) years and a median follow-up of 12.9 years. Among all methods, only OCMB, LS-OCMB, and Reibergram significantly identified patients at risk of some of the pre-established outcomes, being LS-OCMB the technique with the strongest associations. Adjusted hazard ratio (aHR) of LS-OCMB for predicting a second relapse was 2.50 (95% CI 1.72-3.64, p < 0.001). The risk of reaching EDSS scores of 4 and 6 and SPMS was significantly higher among patients with LS-OCMB (aHR 2.96, 95% CI 1.54-5.71, p = 0.001; aHR 4.96, 95% CI 2.22-11.07, p < 0.001; and aHR 2.31, 95% CI 1.08-4.93, p = 0.03, respectively). CONCLUSIONS: ITMS predicts an aggressive MS at disease onset, especially when detected as LS-OCMB. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that lipid-specific IgM oligoclonal bands can predict progression from CIS to MS and a worse disease course over a follow-up of at least 2 years.

Intrathecal Immunoglobulin M Synthesis is an Independent Biomarker for Higher Disease Activity and Severity in Multiple Sclerosis.

OBJECTIVE: We aimed to determine in relapsing multiple sclerosis (MS) whether intrathecal synthesis of immunoglobulin (Ig) M and IgG is associated with outcomes reflecting inflammatory activity and chronic worsening. METHODS: We compared cerebrospinal fluid analysis, clinical and magnetic resonance imaging data, and serum neurofilament light chain (sNfL) levels at baseline and follow-up in 530 patients with relapsing MS. Patients were categorized by the presence of oligoclonal IgG bands (OCGB) and intrathecal synthesis of IgG and IgM (intrathecal fraction [IF]: IgGIF and IgMIF ). Relationships with the time to first relapse, sNfL concentrations, T2-weighted (T2w) lesions, MS Severity Score (MSSS), and time to initiation of high-efficacy therapy were analyzed in covariate-adjusted statistical models. RESULTS: By categorical analysis, in patients with IgMIF the median time to first relapse was 28 months shorter and MSSS on average higher by 1.11 steps compared with patients without intrathecal immunoglobulin synthesis. Moreover, patients with IgMIF had higher sNfL concentrations, more new/enlarging T2w lesions, and higher total T2w lesion counts (all p ≤ 0.01). These associations were absent or equally smaller in patients who were positive for only OCGB or OCGB/IgGIF . Furthermore, quantitative analyses revealed that in patients with IgMIF ≥ median, the time to first relapse and to initiation of high-efficacy therapy was shorter by 32 and by 203 months, respectively (both p < 0.01), in comparison to patients with IgMIF < median. Dose-dependent associations were also found for IgMIF but not for IgGIF with magnetic resonance imaging-defined disease activity and sNfL. INTERPRETATION: This large study supports the value of intrathecal IgM synthesis as an independent biomarker of disease activity and severity in relapsing MS. ANN NEUROL 2021;90:477-489.

Kappa Free Light Chains in the Context of Blood Contamination, and Other IgA- and IgM-Related Cerebrospinal Fluid Disease Pattern.

In this retrospective, monocentric cohort study, we tested if an intrathecal free light chain kappa (FLC-k) synthesis reflects not only an IgG but also IgA and IgM synthesis. We also analysed if FLC-k can help to distinguish between an inflammatory process and a blood contamination of cerebrospinal fluid (CSF). A total of 296 patient samples were identified and acquired from patients of the department of Neurology, University Medicine Greifswald (Germany). FLC-k were analysed in paired CSF and serum samples using the Siemens FLC-k kit. To determine an intrathecal FLC-k and immunoglobulin (Ig) A/-M-synthesis we analysed CSF/serum quotients in quotient diagrams, according to Reiber et al. Patient samples were grouped into three cohorts: cohort I (n = 41), intrathecal IgA and/or IgM synthesis; cohort II (n = 16), artificial blood contamination; and the control group (n = 239), no intrathecal immunoglobulin synthesis. None of the samples had intrathecal IgG synthesis, as evaluated with quotient diagrams or oligoclonal band analysis. In cohort I, 98% of patient samples presented an intrathecal synthesis of FLC-k. In cohort II, all patients lacked intrathecal FLC-k synthesis. In the control group, 6.5% presented an intrathecal synthesis of FLC-k. The data support the concept that an intrathecal FLC-k synthesis is independent of the antibody class produced. In patients with an artificial intrathecal Ig synthesis due to blood contamination, FLC-k synthesis is lacking. Thus, additional determination of FLC-k in quotient diagrams helps to discriminate an inflammatory process from a blood contamination of CSF.

Ocular Findings in Infants with Congenital Toxoplasmosis after a Toxoplasmosis Outbreak.

PURPOSE: We investigated the prevalence of ocular abnormalities in infants vertically exposed to Toxoplasma gondii infection during an outbreak in Santa Maria City, Brazil. DESIGN: Consecutive case series. PARTICIPANTS: A total of 187 infants were included. METHODS: The infants were recruited from January 2018 to November 2019. All mothers were screened for syphilis and human immunodeficiency virus before delivery. Toxoplasmosis infection was confirmed in all mothers and infants based on the presence of serum anti-T. gondii immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies. All infants underwent an ophthalmologic examination; ocular abnormalities were documented using a wide-field digital imaging system. Neonatal cranial sonography or head computed tomography was performed in 181 infants, and the cerebrospinal fluid (CSF) was screened for anti-T. gondii IgG and IgM antibodies in 159 infants. Peripheral blood samples from 9 infants and their mothers were analyzed for the presence of T. gondii DNA by real-time polymerase chain reaction. MAIN OUTCOME MEASURES: Ocular abnormalities associated with congenital toxoplasmosis. RESULTS: A total of 187 infants were examined. Twenty-nine infants (15.5%) had congenital toxoplasmosis, of whom 19 (10.2%) had ocular abnormalities, including retinochoroiditis in 29 of 38 eyes (76.3%), optic nerve abnormalities in 5 eyes (13.2%), microphthalmia in 1 eye (2.6%), and cataract in 2 eyes (5.3%). Bilateral retinal choroidal lesions were found in 10 of 19 infants (52.6%). Nine eyes of 6 infants had active lesions, with retinal choroidal cellular infiltrates at the first examination. Thirteen (7.2%) of 181 infants screened presented with cerebral calcifications. Eighty-three percent of the screened infants were positive for anti-T. gondii IgG and negative for IgM antibodies in the CSF. Congenital toxoplasmosis was higher in mothers infected during the third pregnancy trimester, and maternal treatment during pregnancy was not associated with a lower rate of congenital toxoplasmosis. CONCLUSIONS: High prevalence rates of clinical manifestations were observed in infants with congenital toxoplasmosis after a waterborne toxoplasmosis outbreak, the largest yet described. Cerebral calcifications were higher in infants with ocular abnormalities, and maternal infection during the third pregnancy trimester was associated with a higher rate of congenital toxoplasmosis independent of maternal treatment.

MicroRNAs of Human Herpesvirus 6A and 6B in Serum and Cerebrospinal Fluid of Multiple Sclerosis Patients.

Human herpesvirus-6A (HHV-6A) and -6B (HHV-6B) might be involved in the etiopathogenesis of multiple sclerosis (MS), especially the HHV-6A. We aim at assessing, for the first time in the scientific literature, the HHV-6A/B microRNAs in MS patients. We analyzed the miRNAs of HHV-6A: miR-U86, and -6B: hhv6b-miR-Ro6-1, -2, -3-3p, -3-5p, and -4 in paired samples of serum and CSF of 42 untreated MS patients and 23 patients with other neurological diseases (OND), using Taqman MicroRNA Assays. Intrathecal HHV-6A/B antibody production and anti-HHV-6A/B IgG/IgM levels in serum were measured. MS clinical data were available. We detected the following miRNAs: hhv6b-miR-Ro6-2 (serum: MS:97.7%, OND:95.7%; CSF: MS:81%, OND:86.4%), 3-3p (serum: MS:4.8%, OND:0%; CSF: MS:2.4%, OND:4.5%), -3-5p (serum: MS:95.2%, OND:91.3%; CSF: MS:50%, OND:54.5%), and miR-U86 (serum: MS:54.8%, OND:47.8%; CSF: MS:11.9%, OND:9.1%). In the serum of the whole population (MS and OND patients) we found a significant correlation between the levels of hhv6b-miR-Ro6-2 and -3-5p (Spearman r = 0.839, pcorr = 3E-13), -2 and miR-U86 (Spearman r = 0.578, pcorr = 0.001) and -3-5p and miR-U86 (Spearman r = 0.698, pcorr = 1.34E-5); also in the CSF, between hhv6b-miR-Ro6-2 and -3-5p (Spearman r = 0.626, pcorr = 8.52E-4). These correlations remained statistically significant when both populations were considered separately. The anti-HHV-6A/B IgG levels in CSF and the intrathecal antibody production in positive MS patients for hhv6b-miR-Ro6-3-5p were statistically significant higher than in the negative ones (pcorr = 0.006 and pcorr = 0.036). The prevalence of miR-U86 (30.8%) in the CSF of individuals without gadolinium-enhancing lesions was higher (p = 0.035) than in the ones with these lesions (0%); however, the difference did not withstand Bonferroni correction (pcorr = 0.105). We propose a role of HHV-6A/B miRNAs in the maintenance of the viral latency state. Further investigations are warranted to validate these results and clarify the function of these viral miRNAs.

Semi-automated methodology for detection of IgM oligoclonal bands in cerebrospinal fluid and serum samples.

Among the new biomarkers to propose therapeutic decisions in patients suffering from multiple sclerosis (MS) are the IgM oligoclonal bands (OCBs) in cerebrospinal fluid (CSF). At the current time, however, IgM OCBs are detected in laboratories at investigation level and not in the routine practice due to their complexity. For this, we have applied a semi-automated method based on an isoelectrofocusing platform from Sebia of wide availability in clinical laboratories. The IgM OCBs results were validated in paired samples of CSF and serum from patients with MS previously carried out in a reference laboratory. We found a sensitivity of 91.67%, in agreement with previous data obtained with the reference method for IgM OCBs.

Coronavirus disease 2019 associated with aggressive neurological and mental abnormalities confirmed based on cerebrospinal fluid antibodies: A case report.

INTRODUCTION: Coronavirus disease (COVID-19) is spreading worldwide. The reported possible neurological symptoms are varied and range from subtle neurologic deficits to unconsciousness. Knowledge regarding the detection, diagnosis, treatment, and follow-up of COVID-19-associated neurological damage is still limited. We report a case of serious neurological damage and mental abnormalities in a patient who was finally confirmed to have COVID-19 based on IgM and IgG antibodies in the cerebrospinal fluid (CSF). PATIENT CONCERNS: A 68-year-old man had slight flu-like symptoms and transient loss of consciousness in early February. Exaggerated unconsciousness and deteriorating mental abnormalities occurred over the next month without severe respiratory symptoms. Craniocerebral computed tomography showed normal results, but antibodies against severe acute respiratory syndrome coronavirus 2 were 100 times higher in the CSF than in the serum; tests for viral ribonucleic acid showed negative results with both a nasopharyngeal swab and CSF sample. DIAGNOSIS: COVID-19 pneumonia was diagnosed based on symptoms and positive results for IgM and IgG in the CSF. INTERVENTIONS: Antiviral, fluid, and nutritional support were administered for 30 days before admission without obvious improvement. A further 18 days of routine antiviral therapy, immunoglobulin therapy (10 g per day for 5 days), and antipsychotic drug treatment were administered. OUTCOMES: The patient's neurological and mental abnormalities were greatly ameliorated. He was discharged with mild irritability, slight shaking of the hands, and walking fatigue. These symptoms have persisted up to our last follow-up (May 4, 2020). CONCLUSION: We believe this is the first case involving neural system injury in a patient who confirmed COVID-19 based on CSF antibody test results. Negative ribonucleic acid test results, strong positivity for antibodies, and high protein levels in the CSF suggest the possibility of autoimmune encephalitis secondary to COVID-19. This case highlights additional novel symptoms of COVID-19, and these data are important for the assessment and follow-up of COVID-19 patients.

Lipid-specific IgMs induce antiviral responses in the CNS: implications for progressive multifocal leukoencephalopathy in multiple sclerosis.

Progressive multi-focal leukoencephalopathy (PML) is a potentially fatal encephalitis caused by JC polyomavirus (JCV). PML principally affects people with a compromised immune system, such as patients with multiple sclerosis (MS) receiving treatment with natalizumab. However, intrathecal synthesis of lipid-reactive IgM in MS patients is associated with a markedly lower incidence of natalizumab-associated PML compared to those without this antibody repertoire. Here we demonstrate that a subset of lipid-reactive human and murine IgMs induce a functional anti-viral response that inhibits replication of encephalitic Alpha and Orthobunyaviruses in multi-cellular central nervous system cultures. These lipid-specific IgMs trigger microglia to produce IFN-ß in a cGAS-STING-dependent manner, which induces an IFN-α/ß-receptor 1-dependent antiviral response in glia and neurons. These data identify lipid-reactive IgM as a mediator of anti-viral activity in the nervous system and provide a rational explanation why intrathecal synthesis of lipid-reactive IgM correlates with a reduced incidence of iatrogenic PML in MS.

[Hemicerebellitis due to chikungunya associated with refractory status epilepticus in the paediatric age]. / Hemicerebelitis por chikungunya asociado a estado epiléptico refractario en edad pediátrica.

TITLE: Hemicerebelitis por chikungunya asociado a estado epiléptico refractario en edad pediátrica.

Investigation of Japanese encephalitis virus as a cause of acute encephalitis in southern Pakistan, April 2015-January 2018.

BACKGROUND: Japanese encephalitis (JE) occurs in fewer than 1% of JE virus (JEV) infections, often with catastrophic sequelae including death and neuropsychiatric disability. JEV transmission in Pakistan was documented in 1980s and 1990s, but recent evidence is lacking. Our objective was to investigate JEV as a cause of acute encephalitis in Pakistan. METHODS: Persons aged ≥1 month with possible JE admitted to two acute care hospitals in Karachi, Pakistan from April 2015 to January 2018 were enrolled. Cerebrospinal fluid (CSF) or serum samples were tested for JEV immunoglobulin M (IgM) using the InBios JE DetectTM assay. Positive or equivocal samples had confirmatory testing using plaque reduction neutralization tests. RESULTS: Among 227 patients, testing was performed on CSF in 174 (77%) and on serum in 53 (23%) patients. Six of eight patient samples positive or equivocal for JEV IgM had sufficient volume for confirmatory testing. One patient had evidence of recent West Nile virus (WNV) neurologic infection based on CSF testing. One patient each had recent dengue virus (DENV) infection and WNV infection based on serum results. Recent flavivirus infections were identified in two persons, one each based on CSF and serum results. Specific flaviviruses could not be identified due to serologic cross-reactivity. For the sixth person, JEV neutralizing antibodies were confirmed in CSF but there was insufficient volume for further testing. CONCLUSIONS: Hospital-based JE surveillance in Karachi, Pakistan could not confirm or exclude local JEV transmission. Nonetheless, Pakistan remains at risk for JE due to presence of the mosquito vector, amplifying hosts, and rice irrigation. Laboratory surveillance for JE should continue among persons with acute encephalitis. However, in view of serological cross-reactivity, confirmatory testing of JE IgM positive samples at a reference laboratory is essential.

Acute Flaccid Paralysis as the Initial Manifestation of Japanese Encephalitis: a Case Report.

Japanese encephalitis (JE) is a clinical disease caused by inflammation of the central nervous system. The symptoms of this disease range broadly in severity from mild febrile illness to acute meningomyeloencephalitis. JE has been associated with a variety of neurological abnormalities, such as altered sensorium, seizures, focal neurological deficit, and acute flaccid paralysis (AFP). However, to date, AFP has never been reported as an initial manifestation of JE. Here, we present a case of AFP manifesting as the initial symptom of JE in a Chinese patient. A 30-year-old Chinese man was admitted to the West China Hospital of Sichuan University after experiencing AFP in the right upper limb, followed by hyperpyrexia and unconsciousness. Assay of cerebrospinal fluid from a lumbar puncture revealed high levels of proteins and anti- JE virus IgM antibodies. Intravenous acyclovir was administered; however, the weakness persisted and more extensive muscle wasting from the proximal to distal right upper limb occurred over 7 months. This case report highlights that JE needs to be added to the differential diagnosis of AFP in adults, especially in JE endemic seasons and areas.

Double Crossed: A Case of La Crosse Encephalitis.

CASE REPORT: A 10-year-old male with T1DM and recent travel to North Carolina presented to an ED with 1 day of fever, vomiting, and headaches. He was discharged home with the presumptive diagnosis of viral gastroenteritis but returned nine hours later, agitated, and unable to speak. CSF showed pleocytosis. MRI brain was normal, and EEG showed intermittent seizures. He was started on antiepileptics. Antibiotics were discontinued after negative bacterial work-up. Repeat MRI brain one week later showed enhancement in the left cerebral cortex. IVIG was started due to concern for autoimmune encephalitis. Repeat lumbar puncture was positive for La Crosse virus IgM. DISCUSSION: This is the first case of La Crosse encephalitis (LACe) reported in Rhode Island.1 La Crosse virus (LACv) is a ssRNA Bunyavirus transmitted by the eastern tree-hole mosquito typically between July and September. LACv is endemic to the upper Midwestern US and Appalachia. In 2018, 81 of 86 total cases reported by the CDC were pediatric. Children are more likely to present with vomiting, seizures, and focal cortical inflammation or cerebral edema on brain imaging. IgM may be negative early in the disease course. Treatment is antiepileptics and supportive care.