Is the Frontal Lobe the Primary Target of SARS-CoV-2?

Acute delirium and other neuropsychiatric symptoms have frequently been reported in COVID-19 patients and are variably referred to as acute encephalopathy, COVID-19 encephalopathy, SARS-CoV-2 encephalitis, or steroid-responsive encephalitis. COVID-19 specific biomarkers of cognitive impairment are currently lacking, but there is some evidence that SARS-CoV-2 could preferentially and directly target the frontal lobes, as suggested by behavioral and dysexecutive symptoms, fronto-temporal hypoperfusion on MRI, EEG slowing in frontal regions, and frontal hypometabolism on 18F-FDG-PET imaging. We suggest that an inflammatory parainfectious process targeting preferentially the frontal lobes (and/or frontal networks) could be the underlying cause of these shared clinical, neurophysiological, and imaging findings in COVID-19 patients. We explore the biological mechanisms and the clinical biomarkers that might underlie such disruption of frontal circuits and highlight the need of standardized diagnostic procedures to be applied when investigating patients with these clinical findings. We also suggest the use of a unique label, to increase comparability across studies.

Acute Encephalitis Syndrome with an Unusual Diagnosis.

Four-year old boy was admitted with acute onset of fever with seizures and altered sensorium. His mother had history of contact with influenza A H1N1 virus (H1N1) infection. Blood counts, electrolytes, blood sugar and ammonia were normal. Liver enzymes were mildly elevated. CSF study showed elevated protein, normal sugar and no pleocytosis. Cerebrospinal fluid (CSF) viral panel was negative. Magnetic resonance imaging brain was suggestive of acute necrotizing encephalopathy. His throat swab and sputum polymerase chain reaction was positive for H1N1. He was managed with ventilation, intravenous steroids and other supportive measures. At discharge his sensorium improved but had neurological sequelae. We are presenting this case as this is a very rare complication of H1N1 infection with high rate of mortality. Early supportive measures and steroids/intravenous immunoglobulin may save the patient.

An Investigation on the Coinfection of Measles and HSV-1 in Hospitalized Acute Encephalitis Syndrome Patients in Eastern India.

Acute encephalitis syndrome (AES) is a clinical condition that occurs due to infectious and noninfectious agents- however, viruses are considered to be the dominant pathogen. agents- however, viruses are considered to be the dominant pathogen. In this study, suspected AES cases were enrolled and tested for viral etiology through serology and polymerase chain reaction (PCR)/reverse transcriptase PCR from August 2012-July 2013. During this period, 820 cases were investigated and 96 cases were diagnosed to have a viral etiology whereas 20 patients had IgM antibodies for measles in serum and HSV-1 DNA in cerebrospinal fluid. All 20 of the patients were children below 14 years of age. The median hospital stay was 15 days (IQR: 14.2-17 days) and median GCS score was 7(IQR: 6-8) and were significantly different with patients with co-infections when comapred with patients having HSV-1 infection only. It may be suspected that the measles infection may have a role in the pathogenesis and thus an impact on the prognosis of the AES when present with HSV-1.

Detection of human parvovirus 4 DNA in the patients with acute encephalitis syndrome during seasonal outbreaks of the disease in Gorakhpur, India.

Seasonal outbreaks of acute encephalitis syndrome (AES) at Gorakhpur, India have been recognized since 2006. So far, the causative agent has not been identified. Use of next generation sequencing identified human parvovirus 4 (HPARV4) sequences in a CSF/plasma pool. These sequences showed highest identity with sequences earlier identified in similar patients from south India. Real-time PCR detected HPARV4 DNA in 20/78 (25.6%) CSF and 6/31 (19.3%) plasma of AES patients. Phylogenetic analysis classified three almost complete genomes and 24 partial NS1 sequences as genotype 2A. The observed association of HPARV4 with AES needs further evaluation. ELISAs for the detection of IgM and IgG antibodies against scrub typhus (Orientia tsutsugamushi, OT) showed ∼70% IgM/IgG positivity suggestive of etiologic association. Prospective, comprehensive studies are needed to confirm association of these agents, singly or in combination with AES in Gorakhpur region.

Dengue virus is an under-recognised causative agent of acute encephalitis syndrome (AES): Results from a four year AES surveillance study of Japanese encephalitis in selected states of India.

BACKGROUND: Acute encephalitis syndrome (AES) surveillance in India has indicated that Japanese encephalitis virus (JEV) accounts for 5-35% of AES cases annually; the etiology remains unknown in the remaining cases. We implemented comprehensive AES surveillance to identify other etiological agents of AES, with emphasis on dengue virus. METHODS: Serum and cerebrospinal fluid (CSF) specimens were collected from patients enrolled prospectively in AES surveillance from 2014-2017 at selected sites of three high burden states of India. All samples were initially tested for JEV IgM. Specimens negative for JEV by serology were tested for IgM to scrub typhus, dengue virus (DEN), and West Nile virus; all JEV IgM-negative CSF samples were tested by PCR for S. pneumoniae, N. meningitidis, H. influenzae, herpes simplex virus type 1, enteroviruses and DEN. RESULTS: Of 10,107 AES patients, an etiology could be established in 49.2% of patients including JEV (16%), scrub typhus (16%) and DEN (5.2%) as the top three agents. Amongst the DEN positive cases (359/6892), seven (2%) were positive only for dengue virus RNA: one in serum and six in CSF. CONCLUSION: Amongst the pathogens identified, dengue accounted for 5% of all AES cases and was one of the three common etiological agents. These results underscore the importance of including dengue virus in routine testing of AES cases.

Emergence of human West Nile Virus infection among pediatric population in Madhya Pradesh, India.

Human infections caused by West Nile virus (WNV) mostly remain subclinical and self-limited. However, nearly 20% infected people suffer from febrile illness and very few of them (<1%) may get neuroinvasive illness. Mortality has been reported among children. India somehow has reported very less number of WNV cases in the past. We collected cerebrospinal fluid (CSF) samples from 75 pediatric age group patients clinically suffering from acute encephalitis syndrome. Three of these samples were positive by reverse transcriptase polymerase chain reaction using pan flavivirus primers. On sequencing of the 212 bp long-amplified fragment, it was found to be WNV belonging to lineage 1. This is probably the first report of WNV causing encephalitis from this central part of India.

Evidence of hepatitis A virus infection in the patients with acute encephalitis syndrome in Gorakhpur region, North India.

The etiological agent remained unidentified in a large number of patients hospitalized for acute encephalitis syndrome (AES) in 2008-2009 in Uttar Pradesh and Bihar, north India. All patients were found to present with fever and altered sensorium, while 28%, 19% and 13% showed hepatomegaly, splenomegaly and meningeal signs, respectively. Involvement mostly of children with abnormal hepatic features prompted us to undertake an exploratory study on viral hepatitis A to determine its association, if any, with hepatic derangements. AES patients (n = 2515) and healthy children (n = 167) were investigated for the presence of serum anti-hepatitis A virus (anti-HAV) IgM and anti-Japanese encephalitis (anti-JE) virus IgM by ELISA. Cerebrospinal fluids (CSFs, n = 595) and rectal swabs (n = 182) were examined for anti-HAV IgM and/or HAV RNA. Anti-HAV IgM was detected in the sera of 14.6% patients as against 6.6% of healthy children (p = 0.0042). Anti-JE virus IgM positivity was Keywords: acute encephalitis syndrome; cerebrospinal fluid; hepatitis A virus; anti-HAV IgM; non-Japanese encephalitis.

Serum Procalcitonin Levels in Acute Encephalopathy with Biphasic Seizures and Late Reduced Diffusion.

Procalcitonin (PCT) is used as a biomarker in severe infections. Here, we retrospectively investigated levels of serum PCT, C-reactive protein (CRP), and inflammatory cytokines (IL-6, TNF-α, and IFN-γ) in the second phase of patients with acute encephalopathy with biphasic seizures and late reduced diffusion (AESD). Nine AESD pediatric patients (4 men, 5 women; AESD group) admitted to Okayama University Hospital from 2010 to 2016 were compared with 10 control patients with febrile seizures (FS) (3 men, 7 women; FS group). Mean PCT concentrations (ng/mL) in the AESD and FS groups were significantly different, at 9.8 ± 6.7 and 0.8 ± 0.9, respectively (p = 0.0011). CRP (mg/dL) were 0.79 ± 0.89 and 1.4 ± 1.0 (p = 0.21), respectively; IL-6 (pg/mL) were 449.7 ± 705.0 and 118.3 ± 145.4 (p = 0.20), respectively; TNF-α (pg/mL) were 18.6 ± 12.5 and 16.6 ± 6.0 (p = 0.67), respectively; and IFN-γ (pg/mL) were 79.6 ± 158.5 and 41.9 ± 63.7 (p = 0.56), respectively. Ratios of PCT to CRP were 27.5 ± 34.2 and 3.2 ± 6.8 (p < 0.0001), respectively. The sensitivity and specificity in the diagnosis of AESD using a cutoff of PCT/CRP ratio of 1.0 were 100% and 80%, respectively. These results suggest that PCT and the PCT/CRP ratio are useful in auxiliary diagnosis of the second stage of AESD, and in AESD, PCT is likely to increase through a different mechanism.

Incidence of Japanese Encephalitis amongst acute encephalitis syndrome cases in upper Assam districts from 2012 to 2014: A report from a tertiary care hospital.

BACKGROUND & OBJECTIVES: Japanese encephalitis (JE) is a major public health problem in India because of high mortality rate and residual neuropsychiatric damage in the survivors. The present study was undertaken to investigate JE positivity amongst patients admitted with acute encephalitis syndrome (AES) in upper Assam districts and different parameters with their changing trends related to it. METHODS: It was a hospital-based prospective cross-sectional study conducted from January 2012 to December 2014. A total of 1707 consecutive non-repetitive hospitalized patients, satisfying the clinical case definition of AES as per the WHO guidelines, were included in the study. Cerebrospinal fluid (CSF) and serum samples were tested for JEV-specific IgM antibodies. RESULTS: Of the 1707 patients admitted, 696 (40.77 %) were diagnosed as JE with male-to-female ratio 1.7:1 and adult to paediatric ratio 2.2:1. Fever (100%), change in mental status (100%), headache (80.02%), neck rigidity (52.01%), unconsciousness (48.99%), seizure (37.64%) and paralysis (11.06%) were the major clinical findings. The majority of cases (94%) were from rural areas. There was a significant association of JE cases with rainy season of the year i.e., June to August (P<0.001). Overall, 14.94 per cent deaths were reported in JE positive cases. INTERPRETATION & CONCLUSIONS: A higher occurrence of JE was observed in above 15 yr age group. Cases were mainly from rural areas, and there was clustering of cases in rainy season.

Neuropathogenesis by Chandipura virus: An acute encephalitis syndrome in India.

Chandipura virus (CHPV) has been contributing to the rising number of premature deaths due to acute encephalitis syndrome for over a decade in India. CHPV belongs to the family Rhabdoviridae. Neuropathogenesis of CHPV has been well established but the exact route of entry into the central nervous system (CNS) and the triggering factor for neuronal death are still unknown. Rabies virus and vesicular stomatitis virus, which are related closely to CHPV, enter the CNS retrogradely from peripheral or olfactory neurons. Disruption of the blood-brain barrier has also been connoted in the entry of CHPV into the CNS. CHPV upon entering the neurons triggers cellular stress factors and release of reactive oxygen species (ROS). The stress granules produced in response to cellular stress have been implicated in viral replication and ROS generation, which stimulates neuronal death. Both these phenomena cohesively explain the neuropathogenesis and neurodegeneration following CHPV infection.