Importance of cerebrospinal fluid investigation during dengue infection in Brazilian Amazonia Region.

BACKGROUND Amazon, the largest tropical forest of the world, has suffered from dengue outbreaks since 1998. Cerebrospinal fluid (CSF) of patients, from Amazonas state, suspected of central nervous system (CNS) viral infection was studied using molecular and immunological methods. OBJECTIVE To evaluate the importance of CSF investigation in patients with acute dengue virus (DENV) infection of CNS. METHODS CSF samples of 700 patients were analysed by reverse transcription polymerase chain reaction (RT-PCR) to detect the presence of dengue virus (DENV) RNA and by enzyme-linked immunosorbent assay (ELISA) to detect presence of DENV specific IgM. FINDINGS DENV infection was detected in 4.3% of the CSF samples; 85.7% (24/28) by DENV IgM and 14.3% (4/28) by viral RNA. DENV detected by viral RNA were to be found serotypes DENV-2 (three patients) and DENV-1 (one patient). The neurological diagnosis in patients CNS infection of DENV included encephalitis (10), meningoencephalitis (10), meningitis (6), acute myelitis (1), and encephalomyelitis (1). The majority (89.3%) had intrathecal inflammation: pleocytosis, hyperproteinorrachia and DENV IgM antibodies. Hypoglycorrhachia and/or high levels of lactate in CSF were found in 36% of the patients. Co-infection (CMV, HIV, EBV, and/or Mycobacterium tuberculosis) was observed in eight (28.6%) cases. CONCLUSIONS We found intense inflammatory CSF that is unusual in CNS disorders caused by dengue infection. It may be due co-infections or the immunogenetic background of the local Amerindian Brazilian population. CSF examination is an important diagnostic support tool for neurological dengue diagnosis.

Meningitis Associated with Simultaneous Infection by Multiple Dengue Virus Serotypes in Children, Brazil.

To determine the causes of viral meningitis, we analyzed 22 cerebrospinal fluid samples collected during the 2014-2015 dengue epidemics in Brazil. We identified 3 serotypes of dengue virus (DENV-1, -2, and -3), as well as co-infection with 2 or 3 serotypes. We also detected the Asian II genotype of DENV-2.

Study of interleukin-6 and interleukin-8 levels in patients with neurological manifestations of dengue.

CONTEXT: Pro-inflammatory markers play a key role in the pathogenesis of various Flavivirus infection. AIM: In this study, we evaluated the role of these markers in neurological manifestations of dengue. SETTINGS AND DESIGNS: Consecutive dengue cases with different neurological manifestations who presented between August 2012 and July 2014 were studied in hospital-based case-control study. MATERIALS AND METHODS: Interleukin (IL-6) and IL-8 level were measured in serum and cerebrospinal fluid (CSF) of dengue cases with different neurological manifestations and also in age- and sex-matched controls. Level was analyzed with various parameters and outcomes. STATISTICAL ANALYSIS: Statistical analysis was done using SPSS version 16.0 by applying appropriate statistical methods. P < 0.05 considered statistically significant. RESULTS: Out of the 40 enrolled cases of dengue with neurological manifestations, 29 had central nervous system and 11 had peripheral nervous system (CNS/PNS) manifestations. In CNS group, both IL-6 and IL-8 (CSF and serum) were significantly elevated (P < 0.001), whereas CSF IL-6 (P = 0.008), serum IL-6 (P = 0.001), and serum IL-8 (P = 0.005) were significantly elevated in PNS group. CSF IL-6, serum IL-6, and IL-8 were significantly elevated in poor outcome patients in CNS group (P < 0.05). CSF IL-6 and IL-8 were significantly elevated in CSF dengue positive cases as compared to CSF negative patients (P < 0.05). Cytokine level was not significantly correlated with neuroimaging abnormality in CNS group. Nine patients died and the remainder recovered. CONCLUSION: Elevated level of IL-6 and IL-8 is associated with different neurological manifestations and poor outcome, but whether they are contributing to neuropathogenesis or simply a correlate of severe disease remains to be determined.

Dengue in patients with central nervous system manifestations, Brazil.

We investigated the prevalence of dengue in patients with suspected viral meningitis/meningoencephalitis in a dengue-endemic area. Cerebrospinal fluid analysis showed positive results and a 6.74× greater likelihood of identifying positive fluid in patients who died. Our findings support testing patients with neurologic manifestations for the virus in dengue-endemic areas.

Complete genome analysis and characterization of neurotropic dengue virus 2 cosmopolitan genotype isolated from the cerebrospinal fluid of encephalitis patients.

Dengue virus (DENV) infection remains a major public health concern in many parts of the world, including Southeast Asia and the Americas. Sri Lanka experienced its largest dengue outbreak in 2017. Neurological symptoms associated with DENV infection have increasingly been reported in both children and adults. Here, we characterize DENV type 2 (DENV-2) strains, which were isolated from cerebrospinal fluid (CSF) and/or serum of patients with dengue encephalitis. Acute serum and CSF samples from each patient were subjected to dengue-specific non-structural protein 1 (NS1) antigen test, IgM and IgG enzyme-linked immunosorbent assay (ELISA), virus isolation, conventional and real-time polymerase chain reaction (PCR), and next-generation sequencing (NGS). Among the 5 dengue encephalitis patients examined, 4 recovered and 1 died. DENV-2 strains were isolated from serum and/or CSF samples of 3 patients. The highest viral genome levels were detected in the CSF and serum of the patient who succumbed to the illness. A phylogenetic tree revealed that the DENV-2 isolates belonged to a new clade of cosmopolitan genotype and were genetically close to strains identified in China, South Korea, Singapore, Malaysia, Thailand, and the Philippines. According to the NGS analysis, greater frequencies of nonsynonymous and synonymous mutations per gene were identified in the nonstructural genes. The full genomes of serum- and CSF-derived DENV-2 from the same patient shared 99.7% similarity, indicating that the virus spread across the blood-brain barrier. This is the first report to describe neurotropic DENV-2 using whole-genome analysis and to provide the clinical, immunological, and virological characteristics of dengue encephalitis patients during a severe dengue outbreak in Sri Lanka in 2017.

Japanese Encephalitis- and Dengue-Associated Acute Encephalitis Syndrome Cases in Myanmar.

This study was conducted to find the burden of dengue virus (DENV) and Japanese encephalitis virus (JEV) among children under the age of 13, who presented with acute encephalitis syndrome at Mandalay Children Hospital in Myanmar in 2013. Molecular and serological investigations were performed on 123 cerebrospinal fluid (CSF) samples collected from these patients. By neutralization tests and/or virus isolation, four (3.3%) JEV- and one DENV-associated encephalitis cases (0.8%) were confirmed. Antibody titer against JEV Genotype 3 was the highest among the laboratory-confirmed JEV cases. One strain of DENV-1 with Genotype 1 was isolated from the CSF sample of the dengue encephalitis patient; this was similar to the virus circulating in the study area and neighboring countries. This study shows that flaviviruses are important pathogens causing encephalitis in Myanmar. Active disease surveillance, vector control, and vaccination programs should be enforced to reduce the morbidity and mortality caused by flavivirus encephalitis.

Oligosymptomatic dengue infection: a potential cause of Guillain Barré syndrome.

BACKGROUND: Dengue infection may cause neurological manifestations such as encephalitis, myelitis, mononeuropathies, acute disseminated encephalomyelitis, and Guillain Barré syndrome (GBS). In endemic regions, the infection course can be oligosymptomatic making difficult the diagnosis of the neurological picture associated with dengue infection. OBJECTIVE: To report dengue infection and GBS association, even in oligosymptomatic cases of this infection. METHOD: During the dengue epidemic in Rio de Janeiro city we looked for GBS cases, testing IgM antibodies for dengue and dengue polymerase chain reaction (PCR) in the cerebrospinal fluid (CSF) and serum. RESULTS: We report seven cases (46.6%), presenting dengue positive IgM in serum but with poor or without clinical symptoms of the previous infection. Two of them had also positive IgM antibodies in CSF. CONCLUSION: These data show that search for dengue infection should be a routine in GBS cases living in endemic areas.

Arboviral Surveillance among Pediatric Patients with Acute Febrile Illness in Houston, Texas.

We instituted active surveillance among febrile patients presenting to the largest Houston-area pediatric emergency department to identify acute infections of dengue virus (DENV), West Nile virus (WNV), and chikungunya virus (CHIKV). In 2014, 1,063 children were enrolled, and 1,015 (95%) had blood and/or cerebrospinal fluid specimens available for DENV, WNV, and CHIKV testing. Almost half (49%) reported recent mosquito bites, and 6% (N = 60) reported either recent international travel or contact with an international traveler. None were positive for acute WNV; three had false-positive CHIKV results; and two had evidence of DENV. One DENV-positive case was an acute infection associated with international travel, whereas the other was identified as a potential secondary acute infection, also likely travel-associated. Neither of the DENV-positive cases were clinically recognized, highlighting the need for education and awareness. Health-care professionals should consider the possibility of arboviral disease among children who have traveled to or from endemic areas.

Acute disseminated encephalomyelitis in classic dengue.

Neurological manifestation is uncommon in dengue infection. The pathogenesis of central nervous system involvement is controversial. We report a rare case of acute disseminated encephalomyelitis in classic dengue, with isolation of serotype 3 in liquor. This condition was associated with significant structural damage detected by magnetic resonance.

Neurological manifestations in children with dengue fever: an Indian perspective.

Ours was a descriptive observational cross-sectional study carried out in a tertiary care hospital in eastern India over a period of one year to study the profile of neurological involvement in paediatric dengue patients. Of 71 laboratory-confirmed cases, 20 (28.17%) had neurological involvement. Common forms observed were acute encephalopathy (40%), encephalitis (30%), pure motor weakness (15%), transverse myelitis (5%), acute disseminated encephalomyelitis (5%) and Guillain-Barré syndrome (5%). The dengue IgM antibody could be detected in the cerebrospinal fluid of only two patients with encephalitis. Neurological involvement was present in all four patients who died during the study period (two-tailed P value = 0.005).

Etiological agents of viral meningitis in children from a dengue-endemic area, Southeast region of Brazil.

Meningitis is a disease with a global distribution that constitutes a worldwide burden, with viruses as the primary etiologic agents. The range of viral meningitis severity depends mainly on age, immune status and etiological agent. The aim of this work was to investigate the suspected cases of viral meningitis using molecular techniques to confirm the viral infection. The diagnosed virus was correlated with clinical findings and cytochemical parameters in cerebrospinal liquid (CSF) of patients. CSF of 70 children with the presumptive diagnosis of viral meningitis was analyzed by real time PCR (qPCR). Viruses were identified by qPCR in 44 CSF samples (62.9%). Among them, 31 were identified as Enterovirus (ENTV) (70.4%), six as Human herpes virus 3 (HHV-3) (13.6%), five as Dengue virus (DENV) (11.7%), one as Human herpes virus 1-2 (2.3%) and one as Human herpes virus 5 (2.3%). Patients in the HHV-positive groups had increased percentage of polymorphonuclear neutrophils (PMN) (mean of 81%) while the groups of patients with DENV and ENTV had a mean of 30.9%. This study contributes to the knowledge of the epidemiological distribution of viral agents in CNS infections in children. In addition, it raises the relevance of DENV as an agent of CNS infection, and reinforces the importance for molecular in the cases of CNV infection.

Acute disseminated encephalomyelitis complicating dengue infection with neuroimaging mimicking multiple sclerosis: A report of two cases.

Acute disseminated encephalomyelitis (ADEM) complicating dengue infection is still exceedingly rare even in endemic countries such as Malaysia. Here we report two such cases, the first in an elderly female patient and the second in a young man. Both presented with encephalopathy, brainstem involvement and worsening upper and lower limb weakness. Initial magnetic resonance imaging (MRI) of the brain was normal in the first case. Serum for dengue Ig M and NS-1 was positive in both cases. Cerebrospinal fluid (CSF) showed pleocytosis in both with Dengue IgM and NS-1 positive in the second case but not done in the first. MRI brain showed changes of perpendicular subcortical palisading white matter, callosal and brainstem disease mimicking multiple sclerosis (MS) in both patients though in the former case there was a lag between the onset of clinical symptoms and MRI changes which was only clarified on reimaging. The temporal evolution and duration of the clinical symptoms, CSF changes and neuroimaging were more suggestive of Dengue ADEM rather than an encephalitis though initially the first case began as dengue encephalitis. Furthermore in dengue encephalitis neuroimaging is usually normal or rarely edema, haemorrhage, brainstem, thalamic or focal lesions are seen. Therefore, early recognition of ADEM as a sequelae of dengue infection with neuroimaging mimicking MS and repeat imaging helped in identifying these two cases. Treatment with intravenous steroids followed by maintenance oral steroids produced good outcome in both patients.

Dengue encephalitis: a true entity?

Involvement of the central nervous system in dengue fever and dengue hemorrhagic fever has always been thought to be secondary to vasculitis with resultant fluid extravasation, cerebral edema, hypoperfusion, hyponatremia, liver failure, and/or renal failure. Thus, the condition has been referred to as dengue encephalopathy. Encephalitis or direct involvement of the brain by the virus was thought to be unlikely. This paper reports on six children who were seen over a period of two years presenting on the second or third day of illness with dengue encephalitis. The diagnosis was based upon a clinical picture of encephalitis and confirmed by cerebrospinal fluid (CSF) microscopy and electroencephalography changes. All six cases were confirmed dengue infections. Dengue 3 virus was isolated from the CSF of four cases and in one case, dengue 2 was detected by the polymerase chain reaction in both the CSF and blood. In the sixth case, virologic evidence was negative but dengue immunoglobulin M was detected in the CSF and blood. Since the onset of encephalitis appears early in the course of illness coinciding with the viremic phase, we postulate that the virus crosses the blood-brain barrier and directly invades the brain causing encephalitis. This study provides strong evidence that dengue 2 and 3 viruses have neurovirulent properties and behave similarly to other members of the Flaviviridae.

Detection of IgM antibodies from cerebrospinal fluid and sera of dengue fever patients.

During the dengue epidemic from late 1987 to 1989, 6 specimens of cerebrospinal fluid (CSF) and sera for IgM detection were collected from 4 cases virologically confirmed dengue patients who had neural symptoms. Another 20 serum specimens, which had been diagnosed as dengue infection either virologically or serologically, were sent to the laboratory from Kaohsiung Medical College Hospital. All these specimens were also taken to detect the existence of IgM. The results showed that IgM could be detected from 14 out of 20 serum specimens. One of the positive specimens showed IgM can last up to 252 days after onset of illness. In addition, IgM was detected from both CSF and sera of all four dengue patients with neural symptoms. The IgM titer in CSF (less than or equal to 1:20) was always lower than that in serum (greater than or equal to 1:80). Two cases with sequentially collected specimens showed the fading of IgM titer in CSF. As a matter of fact, it became undetectable about a month after onset of illness, which is apparently different from the situation in serum.

Neurological manifestations in dengue patients.

To determine the frequency and the natural history of neurological manifestations of dengue infection in Thai children, 1,493 children diagnosed with dengue infection by serology and admitted to the Department of Pediatrics, Chulalongkorn Hospital, Bangkok, Thailand from 1987 to 1998 were reviewed from prospectively recorded medical charts. There were 80 children identified with neurological manifestations, an incidence of 5.4% of all dengue patients. Of these, there were 41 males and 39 females, with ages ranging from 3 months to 14 years. They were categorized into 20 cases of dengue fever, 26 cases of dengue hemorrhagic fever and 34 cases of dengue shock syndrome. All cases experienced the neurological manifestations during the febrile stage of the illness. The patients were classified into an encephalitic group (called "dengue encephalopathy") (42), a seizure group (35) and a miscellaneous group (3). Encephalitic patients presented with alteration of consciousness (83.3%), seizure (45.2%), mental confusion (23.8%), nuchal rigidity (21.4%), spasticity of limbs (9.5%), positive clonus (4.8%), hemiplegia (2.4%) and positive kernig (2.4%), and were older than those in the other groups. Patients in the seizure group presented with seizure (100%) and positive clonus (2.9%). Abnormal laboratory findings included hyponatremia, abnormal liver enzymes and CSF pleocytosis. Dengue IgM and dengue PCR were not demonstrated in 16 CSF specimens. An autopsy finding of a child in the encephalitic group showed histologic evidence of encephalitis, the only case of confirmed dengue encephalitis in this study. One patient with encephalitic symptoms suffered from long-term neurological sequelae. The overall mortality rate was 5%. In conclusion, neurological manifestations including seizure and encephalopathy in children with dengue are not uncommon whereas dengue encephalitis is a rare entity.

Neurological complications in dengue infection: a review for clinical practice.

Dengue is an important global public health problem. The World Health Organization estimates that 2/5 of entire world population are in risk of dengue infection. Almost 50 millions cases occur annually, with at least 20 thousand deaths. The etiological agent of this acute febrile disease is a single-strand positive-sense RNA virus of Flavivirus genus. It is an arboviral disease transmitted by Aedes sp. mosquitoes (Aedes aegypti and A. albopictus). Most infected individuals present asymptomatic infection, but some may develop clinical signs. Therefore, a wide spectrum of illness can be observed, ranging from unapparent, mild disease, called dengue fever, to a severe and occasionally fatal dengue hemorrhagic fever/dengue shock syndrome. Currently, neurological manifestations related to dengue infections are increasingly been observed and appears as a challenge for medical practice. In this study the neurological complications of dengue infection will be reviewed, focusing a better understanding of the disease for the clinical practice.

Identification of Oropouche Orthobunyavirus in the cerebrospinal fluid of three patients in the Amazonas, Brazil.

Oropouche fever is the second most frequent arboviral infection in Brazil, surpassed only by dengue. Oropouche virus (OROV) causes large and explosive outbreaks of acute febrile illness in cities and villages in the Amazon and Central-Plateau regions. Cerebrospinal fluid (CSF) samples from 110 meningoencephalitis patients were analyzed. The RNA extracted from fluid was submitted to reverse transcription-polymerase chain reaction and sequencing to identify OROV. Three CSF samples showed the presence of OROV causing infection in the central nervous system (CNS). These patients are adults. Two of the patients had other diseases affecting CNS and immune systems: neurocysticercosis and acquired immunodeficiency syndrome, respectively. Nucleotide sequence analysis showed that the OROV from the CSF of these patients belonged to genotype I. We show here that severe Oropouche disease is occurring during outbreaks of this virus in Brazil.