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PubMed1995

[Acute encephalitis and bacterial meningitis in children in Aichi Prefecture (1984-1993)].

A survey was performed of acute encephalitis and bacterial meningitis in infancy and childhood from 1984 to 1993 using a questionnaire directed to departments of pediatrics in large hospitals in Aichi prefecture. The case records for 391 patients with acute encephalitis including related diseases and 328 patients with bacterial meningitis were obtained from 63 hospitals. Of 391 patients with acute encephalitis, 224 were male and 167 were female. Of 328 patients with bacterial meningitis, 200 were male and 128 were female. Sex ratio were 1.3, 1.6 respectively. Of the patients, 52.4% of encephalitis and 84.8% of meningitis were under 4 years of age and 0 year olds made up 53.7% of the latter. The causes of these diseases were confirmed in 38.7% and 82.9% of the encephalitis and meningitis patients, respectively, etiologically. In encephalitis, rubella virus was the most frequent with 29 cases, followed by measles virus (27 cases), herpes simplex virus (24) and varicella-zostervirus (19). In meningitis H. influenzae (95 cases), S. pneumoniae (56), Group B streptococcus (41) and E. coli (27) were frequently diagnosed. These diseases showed respective patterns of age distribution and clinical course, and moreover, the increases in their onset were clearly related to the prevalence of causal infections. Therefore, the results of this study should be utilized in the development of administrative measures for prevention of these diseases.

Acute Disease↗
PubMed2002

Burden of encephalitis-associated hospitalizations in the United States, 1988-1997.

Analysis of the National Hospital Discharge Survey data for 1988-1997 revealed a substantial disease burden associated with encephalitis in the United States: on average, there were nearly 19,000 hospitalizations (7.3 hospitalizations per 100,000 population), 230,000 hospital days, and 1400 deaths annually. For most encephalitis-associated hospitalizations (59.5%), the etiologic agent was unknown or not recorded; the most common etiologic categories among known causes were "viral" (38.2%) and "other infectious" (34.1%). The most common individual diagnoses with known agents were herpetic and toxoplasmic encephalitides (each associated with an annual average of 2100 hospitalizations). Human immunodeficiency virus infection was listed among discharge diagnoses for 15.6% of hospitalizations. Rates of encephalitis-associated hospitalization were highest for children <1 year old and persons > or =65 years old. The etiology of encephalitis was unknown for persons > or =65 years old significantly more often than it was for younger persons. The average cost of an encephalitis-associated hospitalization, as determined by the Healthcare Cost and Utilization Project for 1997, was $28,151, for an annual national cost of hospitalization of $650 million.

Adolescent↗
PubMed1996

[Surveillance of St. Louis encephalitis, Eastern equine and Western equine in the province of Ciego de Avila].

Serological studies were carried out using the haemagglutination inhibition and neutralization tests so as to know the circulation dynamics of some arboviruses with the use of Western and Eastern equine encephalitis antigens and St Louis encephalitis antigens in human serum from sound and symptomatic individuals, as well as from sentinel birds, between 1987 and 1991, and during 1994. 1.7% of the asymptomatic subjects tested presented neutralizing antibodies to to Eastern equine and 4.8% to St Louis encephalitis. 16 patients with seroconversion by haemagglutination inhibition to St Louis virus were detected. Surveillance of sentinel birds showed that during 1988, 1989, and 1994. St. Louis circulated in the municipalities of Morón, Bolivia and Chambas; whereas in the latter the Eastern equine encephalitis circulated in 1988 and 1989. Antibodies to Western equine encephalitis were detected in sound individuals by haemagglutination inhibition due seemingly to heterologous antibodies, since there were no neutralizing antibodies against this virus.

Antibodies, Viral↗
PubMed2006

Visual influences on primate encephalization.

Primates differ from most other mammals in having relatively large brains. As a result, numerous comparative studies have attempted to identify the selective variables influencing primate encephalization. However, none have examined the effect of the total amount of visual input on relative brain size. According to Jerison's principle of proper mass, functional areas of the brain devoted primarily to processing visual information should exhibit increases in size when the amount of visual input to those areas increases. As a result, the total amount of visual input to the brain could exert a large influence on encephalization because visual areas comprise a large proportion of total brain mass in primates. The goal of this analysis is to test the expectation of a direct relationship between visual input and encephalization using optic foramen size and optic nerve size as proxies for total visual input. Data were collected for a large comparative sample of primates and carnivorans, and three primary analyses were undertaken. First, the relationship between relative proxies for visual input and relative endocranial volume were examined using partial correlations and phylogenetic comparative methods. Second, to examine the generality of the results derived for extant primates, a parallel series of partial correlation and comparative analyses were undertaken using data for carnivorans. Third, data for various Eocene and Oligocene primates were compared with those for living primates in order to determine whether the fossil taxa demonstrate a similar relationship between relative brain size and visual input. All three analyses confirm the expectations of proper mass and favor the conclusion that the amount of visual input has been a major influence on the evolution of relative brain size in both primates and carnivorans. Furthermore, this study suggests that differences in visual input may partly explain (1) the high encephalization of primates relative to the primitive eutherian condition, (2) the high encephalization of extant anthropoids relative to other primates, and (3) the very low encephalization of Eocene adapiforms.

Animals↗
PubMed1998

A comparison of encephalization between odontocete cetaceans and anthropoid primates.

There have been very few studies of brain size and encephalization in cetaceans and essentially none that have made direct quantitative comparisons of cetaceans and another mammalian group using large normative samples. In the present study two different measures of encephalization were calculated and used to rank and compare 21 odontocete species and 60 anthropoid primate species. Comparisons were made both within and between the two groups. Results show that the encephalization level of Homo sapiens is still extraordinary relative to that of nonhuman species. Nevertheless, a subset of delphinid odontocetes are significantly more highly encephalized than the most highly encephalized anthropoid primates and narrow the gap in encephalization between humans and nonhumans substantially. These findings may have implications for comparative models of the relative importance of brain size versus brain organization for the evolution of intelligence.

Animals↗
PubMed2006

Characteristic abnormalities in cerebrospinal fluid biochemistry in children with cerebral malaria compared to viral encephalitis.

BACKGROUND: In developing countries where Plasmodium falciparum malaria is endemic, viral encephalitis and cerebral malaria are found in the same population, and parasitemia with Plasmodium falciparum is common in asymptomatic children. The objective of this study was to investigate the cerebrospinal fluid (CSF) biochemistry in children with cerebral malaria compared to those with presumed viral encephalitis. METHODS: We studied the following CSF parameters: cell count, glucose, protein, lactic dehydrogenase (LDH) and adenosine deaminase (ADA) levels, in children with cerebral malaria, with presumed viral encephalitis, and in control subjects who had a lumbar puncture after a febrile convulsion with postictal coma. RESULTS: We recruited 12 children with cerebral malaria, 14 children with presumed viral encephalitis and 20 controls prospectively, over 2 years in the Government General Hospital in Kakinada, India. Patients with cerebral malaria had significantly lower CSF glucose, and higher protein, LDH, CSF/blood LDH ratio and CSF ADA levels but a lower CSF/serum ADA ratio compared to controls (p < 0.01). Patients with cerebral malaria had lower CSF white cell count, glucose, protein, LDH levels and CSF/serum ADA ratio compared to patients with presumed viral encephalitis. CSF/serum ADA ratio was lower in patients with cerebral malaria due to the fact that serum ADA levels were significantly higher in patients with cerebral malaria compared to the other two groups. A CSF/serum ADA ratio of <0.38 and a CSF glucose level of <3.4 mmol/l were selected as the cut-off values with the highest sensitivities and specificities for comparing the two conditions. CONCLUSION: CSF/serum ADA ratio and CSF glucose levels were the best discriminators of cerebral malaria from presumed viral encephalitis in our study. Further studies are needed to explore their usefulness in epidemiological studies.

Journal Article↗
PubMed2000

[Identification of the encephalitis equine virus, Parana, Brazil].

INTRODUCTION: In the period of 1996-1999 some virus associated with encephalitis have been reported in horses from different regions of Paraná State, Brazil. To identify the etiologic agent associated with this illness, mosquitoes and serum samples were collected in the endemic area. METHODS: The study area corresponded to four municipalities of Paraná State, Brazil. Mosquitoes were captured in Shannon trap and human bait. After identification, they were processed for virus isolation. Blood of equines were collected in the municipalities of Querência do Norte and Colorado. Antibodies to different Alphavirus and Flavivirus were analyzed by hemagglutination inhibition test. Specific seroneutralization reactions were performed in those sera with a positive reaction in the hemagglutination test. RESULTS: The mosquitoes genus collected were: Culex, Aedes, Mansonia, Coquillettidia, Psorophora, Sabethes, Wyeomyia, and Limatus. Even thought no virus was isolated, serologic analyses showed hemagglutinazing antibodies to Eastern equine encephalitis, Mucambo, Pixuna, Maguari, and St Luis encephalitis viruses. The neutralization test showed specific reaction to Eastern equine encephalitis virus in 12 tested sera. CONCLUSIONS: Species of mosquitoes that could be potential vectors of encephalitis, buniavirus, and other arboviruses of epidemiological importance were collected. It is believed that Eastern equine encephalitis virus affected the equines populations in the study regions because of the symptoms and antibodies for the virus in the sera detected in these equines.

Alphavirus↗
PubMed1992

[Teratogenic effect of the Venezuelan equine encephalitis virus: a review of the problem].

Clinical findings on Venezuelan Equine Encephalitis virus infection and the teratogenic effects of several Togaviruses are described. Similarities between the intrauterine alterations induced by Venezuelan Equine Encephalitis virus and rubella virus are pointed out. Findings described by Wenger in 1967 were those of massive cerebral necrosis in fetuses of women presumably suffering of encephalitis and they are commented along with the development of an animal experimental model at the end of 1970-1980. Pathogenesis of the intrauterine infection seemed to be related to changes in the placental vessels, vascular changes in the central nervous system were also described in rats surviving Venezuelan Equine Encephalitis experimental infection; similar changes were described in the brain of children with post rubella syndrome. The need for multidisciplinary studies in the endemic areas of Venezuelan Equine Encephalitis in order to detect sequelae of the viral effects in utero is emphasized. Finally, some experimental animal models are proposed to examine diverse aspects on intrauterine effect of Venezuelan Equine Encephalitis virus.

Animals↗
PubMed1996

Amnesia in acute herpetic and nonherpetic encephalitis.

OBJECTIVES: To evaluate how often global amnesia syndrome is encountered as a sequel of herpes simplex virus type 1 encephalitis (HSVE) and in other types of acute encephalitides, and to evaluate whether there are qualitative differences in amnesia caused by different encephalitides. SUBJECTS: Forty-five consecutive patients with encephalitis (mean age, 40.8 years) studied prospectively within a 5-year period, 8 of whom had HSVE. There were 24 normal controls. MEASURES: Neuropsychological assessment and memory evaluation after the acute stage of encephalitis, as well as at follow-up after 27.7 +/- 18.6 months. RESULTS: Three patients (6%), including 1 with HSVE, had persistent anterc grade and retrograde memory defects, typical features of global amnesia. Twelve patients had anterograde amnesia in the first assessment. No statistically significant differences in the memory measures were found between the HSVE (n = 4) and the non-HSVE (n = 8) groups. Some patients had predominantly semantic difficulty, some had a "frontal-type" memory disorder, and in some patients rapid forgetting was the prominent feature. CONCLUSIONS: The frequency of amnesia can reliably be evaluated only in consecutive series of patients. Previous literature, mainly case reports, may give the impression that global amnesia is a common consequence of encephalitis. Our findings do not support that view. Furthermore, there are clear differences in the quality of the memory impairment between cases of acute encephalitides. Our findings suggest that amnesia as a consequence of encephalitis, even HSVE, should not be considered a uniform phenomenon.

Acute Disease↗
PubMed2005

Empiric acyclovir is infrequently initiated in the emergency department to patients ultimately diagnosed with encephalitis.

STUDY OBJECTIVE: We evaluate the frequency of empiric acyclovir administration to patients in the emergency department (ED) who are ultimately diagnosed with encephalitis. METHODS: We conducted an explicit retrospective medical record review of consecutive patients discharged with a final diagnosis of herpes simplex encephalitis or viral encephalitis not otherwise specified for the period 1993 to 2003. The frequency of ED administration of empiric acyclovir was measured for patients who met the inclusion criteria of fever, neuropsychiatric abnormality, and cerebrospinal fluid pleocytosis with a negative Gram's stain result in the ED. RESULTS: Of the 90 patients reviewed, 24 (27%) met the inclusion criteria of fever, neuropsychiatric abnormality, and cerebrospinal fluid pleocytosis with a negative Gram's stain result in the ED. Of these 24 patients, 7 (29%) received empiric acyclovir in the ED, 6 (86%) patients after cerebrospinal fluid results were available, with a median time to administration of 1.5 hours (95% confidence interval [CI] 0 to 3.1 hours). The remaining 17 (71%) patients did not receive acyclovir in the ED, with median times of 16 hours (95% CI 7.5 to 44 hours) before initiation of acyclovir in inpatient settings. CONCLUSION: The majority of patients in our institution who were ultimately diagnosed with encephalitis did not receive empiric acyclovir in the ED, despite clinical presentations consistent with encephalitis.

Acyclovir↗
PubMed2006

Murray Valley encephalitis in an adult traveller complicated by long-term flaccid paralysis: case report and review of the literature.

Murray Valley encephalitis (MVE) virus, a mosquito-borne flavivirus, is the most common cause of viral encephalitis in the tropical 'Top End' of northern Australia. Clinical encephalitis due to MVE virus has a mortality rate of approximately 30%, with a similar proportion of patients being left with significant neurological deficits. We report the case of a 25-year-old man from the UK who acquired MVE while travelling through northern Australia. He required prolonged admission to the Intensive Care Unit and several years later remains partly ventilator-dependent, with flaccid quadriparesis. To our knowledge, this is the first reported case of MVE virus-induced flaccid paralysis in an adult in northern Australia, although it is well described in children. Paralysis was thought to be due to anterior horn cell involvement in the spinal cord and extensive bilateral thalamic destruction, both of which are well recognised complications of infection with MVE virus. Cases of flaccid paralysis with similar pathology have been described following infection with the related flavivirus Japanese encephalitis virus as well as more recently with West Nile virus. Our case highlights the potential severity of flavivirus-induced encephalitis and the importance of avoiding mosquito bites while travelling through endemic areas.

Adult↗
PubMed2003

Tick-borne encephalitis.

Tick-borne encephalitis (TBE) is one of the most dangerous human infections occurring in Europe and many parts of Asia. The etiological agent Tick-borne encephalitis virus (TBEV), is a member of the virus genus Flavivirus, of the family Flaviviridae. TBEV is believed to cause at least 11,000 human cases of encephalitis in Russia and about 3000 cases in the rest of Europe annually. Related viruses within the same group, Louping ill virus (LIV), Langat virus (LGTV) and Powassan virus (POWV), also cause human encephalitis but rarely on an epidemic scale. Three other viruses within the same group, Omsk hemorrhagic fever virus (OHFV), Kyasanur Forest disease virus (KFDV) and Alkhurma virus (ALKV), are closely related to the TBEV complex viruses and tend to cause fatal hemorrhagic fevers rather than encephalitis. This review describes the clinical manifestations associated with TBEV infections, the main molecular-biological properties of these viruses, and the different factors that define the incidence and severity of disease. The role of ticks and their local hosts in the emergence of new virus variants with different pathogenic characteristics is also discussed. This review also contains a brief history of vaccination against TBE including trials with live attenuated vaccine and modern tendencies in developing of vaccine virus strains.

Animals↗
PubMed2000

Japanese encephalitis virus up-regulates expression of macrophage migration inhibitory factor (MIF) mRNA in the mouse brain.

Macrophage migration inhibitory factor (MIF) is known as a proinflammatory cytokine, glucocorticoid-induced immunomodulator, and pituitary hormone, and contributes to broad-spectrum immune and inflammatory response. To investigate the expression of MIF in the central nervous system in an event of viral infection, we evaluated MIF mRNA expression in the mouse brain infected with Japanese encephalitis virus (JEV). In situ hybridization revealed that MIF mRNA expression was significantly up-regulated in the whole brain by intracranial JEV inoculation at 2 days post-inoculation (d.p.i.). Neurons as well as glial cells expressed MIF transcripts in which some of these cells were co-labeled by double staining for JEV antigens and MIF mRNA. At 4 d.p.i., when typical symptoms of encephalitis were observed, JEV antigen-positive cells were much increased in parallel with enhanced MIF mRNA, consistent with the results of Northern blot analysis. Reverse transcription-polymerase chain reaction showed that MIF mRNA was minimally changed at 1 d.p.i. in comparison with that at 0 d.p.i., but markedly up-regulated after 2 d.p.i. and sustained up to 4 d.p.i. On the other hand, a significant increase of tumor necrosis factor (TNF)-alpha mRNA was observed after only 3 d.p.i. These data suggest the possibility that MIF is involved in virus-induced encephalitis with regard to not only immune responses in the early stage, but also the exacerbation of inflammation in concert with TNF-alpha in the late stages. This is the first evidence demonstrating that MIF is up-regulated in the case of virus-induced encephalitis, which should contribute to the further understanding of the pathological mechanism of JEV-induced encephalitis.

Animals↗
PubMed1999

LTB4 and LTC4 are absent in the cerebrospinal fluid of human immunodeficiency virus type 1-seropositive persons with toxoplasmic encephalitis: evidence for inhibition of 5-lipoxygenase by Toxoplasma gondii.

Previous studies on macrophages have shown that Toxoplasma gondii alters the metabolism of arachidonic acid with subsequent inability to generate leukotrienes (LT)s. LTB4 and LTC4 were analyzed in cerebrospinal fluid of 3 groups of human immunodeficiency virus (HIV) type 1-seropositive patients: with toxoplasmic encephalitis (TE) (n=10), with herpes simplex encephalitis (n=5), and without encephalitis (n=10) and in HIV-1-seronegative controls without inflammatory diseases (n=30) by specific immunoassays and gas chromatography-mass spectrometry. In HIV-1-seropositive subjects with TE, LTB4 and LTC4 were below the detection limit (<5.0 pg/mL) and thus significantly decreased (P<.01) compared with HIV-1-seropositive patients with herpes simplex encephalitis (LTB4, 148.5+/-47.6 pg/mL; LTC4, 116.4+/-36.9 pg/mL) and in those without encephalitis (LTB4, 46.1+/-16.8 pg/mL; LTC4, 48.3+/-21.3 pg/mL), and in controls (LTB4, 43.6+/-21.2; LTC4, 45.2+/-18.9 pg/mL). These results point to an essential role of inhibition of 5-lipoxygenase with subsequent failure of LT release as an important mechanism for the survival of T. gondii in vivo.

Adult↗
PubMed2004

Impaired T helper 1 function of nonstructural protein 3-specific T cells in Japanese patients with encephalitis with neurological sequelae.

Japanese encephalitis virus (JEV) is the principal cause of viral encephalitis. The predominance of children among patients with encephalitis in areas where JEV is endemic that do not have immunization programs suggests that acquired immunity is critical in protecting adults against symptomatic JEV encephalitis. We characterized and compared the T cell response to nonstructural (NS) protein 3 between healthy individuals naturally exposed to JEV and patients in the convalescent phase of JEV encephalitis. The NS3 protein, used as a fusion to the 11-amino acid protein transduction domain of human immunodeficiency virus Tat, elicited CD4(+) and T helper-dependent CD8(+) T cell responses. The production of interferon (IFN)- gamma by responding T cells was significantly higher in healthy donors than in patients, correlating strongly with acquired protective immunity to JEV. Furthermore, a striking inverse association between IFN- gamma levels and the severity of postencephalitic sequelae in patients implicated a role of IFN- gamma in recovery.

Antibody Formation↗
PubMed2004

Clinical analysis of anti-Ma2-associated encephalitis.

Increasing experience indicates that anti-Ma2-associated encephalitis differs from classical paraneoplastic limbic or brainstem encephalitis, and therefore may be unrecognized. To facilitate its diagnosis we report a comprehensive clinical analysis of 38 patients with anti-Ma2 encephalitis. Thirty-four (89%) patients presented with isolated or combined limbic, diencephalic or brainstem dysfunction, and four with other syndromes. Considering the clinical and MRI follow-up, 95% of the patients developed limbic, diencephalic or brainstem encephalopathy. Only 26% had classical limbic encephalitis. Excessive daytime sleepiness affected 32% of the patients, sometimes with narcolepsy-cataplexy and low CSF hypocretin. Additional hormonal or MRI abnormalities indicated diencephalic-hypothalamic involvement in 34% of the patients. Eye movement abnormalities were prominent in 92% of the patients with brainstem dysfunction, but those with additional limbic or diencephalic deficits were most affected; 60% of these patients had vertical gaze paresis that sometimes evolved to total external ophthalmoplegia. Three patients developed atypical parkinsonism, and two a severe hypokinetic syndrome with a tendency to eye closure and dramatic reduction of verbal output. Neurological symptoms preceded the tumour diagnosis in 62% of the patients. Brain MRI abnormalities were present in 74% of all patients and 89% of those with limbic or diencephalic dysfunction. Among the 34 patients with cancer, 53% had testicular germ-cell tumours. Two patients without evidence of cancer had testicular microcalcification and one cryptorchidism, risk factors for testicular germ-cell tumours. After neurological syndrome development, 17 of 33 patients received oncological treatment (nine also immunotherapy), 10 immunotherapy alone, and six no treatment. Overall, 33% of the patients had neurological improvement, three with complete recovery; 21% had long-term stabilization, and 46% deteriorated. Features significantly associated with improvement or stabilization included, male gender, age <45 years, testicular tumour with complete response to treatment, absence of anti-Ma1 antibodies and limited CNS involvement. Immunosuppression was not found to be associated with improvement but was clearly effective in some patients. Fifteen patients (10 women, five men) had additional antibodies to Ma1. These patients were more likely to have tumours other than testicular cancer and to develop ataxia, and had a worse prognosis than patients with only anti-Ma2 antibodies (two women, 21 men); 67% of deceased patients had anti-Ma1 antibodies. Anti-Ma2 encephalitis (with or without anti-Ma1 antibodies) should be suspected in patients with limbic, diencephalic or brainstem dysfunction, MRI abnormalities in these regions, and inflammatory changes in the CSF. In young male patients, the primary tumour is usually in the testis, in other patients the leading neoplasm is lung cancer.

Adult↗
PubMed1987

Epidemiologic aspects of a St. Louis encephalitis outbreak in Mesa County, Colorado.

An epidemic of St. Louis encephalitis in 1985 in Mesa County, Colorado, led to 17 cases, including one fatality. Risk was associated with advanced age and residence in Grand Junction, the county's principal city. A trend was observed toward higher risk in females. However, increased risk in females was not associated with higher infection rates (increased exposure). Capture enzyme immunoassays detected specific immunoglobulin M (IgM) and immunoglobulin A after infection. A serosurvey of Grand Junction residents disclosed an infection rate of 4.0%, indicating that 1,123 epidemic St. Louis encephalitis infections may have occurred in the city. Evidence of previous St. Louis encephalitis virus infection was found in 11.2% of survey respondents who had neutralizing antibody to the virus without specific IgM. The prevalence of St. Louis encephalitis virus antibody was similar to rates observed in serosurveys undertaken 30 years earlier, indicating that the level of endemic St. Louis encephalitis transmission in the city had not changed appreciably in that interval.

Adolescent↗
PubMed1988

Entomologic studies after a St. Louis encephalitis epidemic in Grand Junction, Colorado.

In 1986, after a St. Louis encephalitis epidemic in Grand Junction, Colorado, in 1985, vector mosquitoes in the city were surveyed to correlate their bionomics and infection rates with the occurrence of human disease. No human cases were reported, but mosquito surveillance disclosed St. Louis encephalitis virus in Culex tarsalis and Culex pipiens pipiens. Mosquitoes were collected with gravid traps designed to attract Cx. p. pipiens and with Centers for Disease Control light traps. Culex p. pipiens was the predominant vector mosquito collected and was captured chiefly in gravid traps. The Culex tarsalis population emerged and expanded approximately one month earlier than did the Cx. p. pipiens population. Consequently, Cx. p. pipiens was the predominant vector species after August. Infection rates throughout the surveillance period (June to September) were severalfold higher in Cx. tarsalis than in Cx. p. pipiens; however, in late summer, diminished numbers of Cx. tarsalis and a persistent population of Cx. p. pipiens resulted in relatively larger numbers of infected Cx. p. pipiens. Thus, the participation of Cx. p. pipiens as a St. Louis encephalitis vector would have been underestimated in previous studies employing light traps alone. These studies provide further evidence that Cx. p. pipiens-associated urban St. Louis encephalitis and rural Cx. tarsalis-associated St. Louis encephalitis cycles may coexist in the West.

Animals↗