| neuroimaging findings in cases of St. Louis encephalitis (StLE) have yet to be reported despite the relatively high frequency of this entity. An epidemic permitted the documentation of isolated hyperintensity of the substantia nigra on T2-weighted images in two patients with StLE. This distribution of MR imaging abnormality in cases of StLE mirrors the reports presented in the literature that implicate the substantia nigra as peculiarly susceptible to the StLE virus. Isolated lesions of the substantia nigra revealed by T2-weighted imaging should suggest the possibility of StLE. ( info) |
| The distinction between intracranial viral infections and inflammatory conditions requiring immunosuppression is important. Although specific laboratory reagents are readily available for some viruses, diagnosis of arbovirus infection is more difficult. Transmission electron microscopy (TEM) theoretically allows identification of viral particles independent of reagent availability, but it has limited sensitivity. We report two cases of human flavivirus encephalitis diagnosed by TEM. Laser scanning confocal microscopy (LSCM) was used in one case to survey unembedded tissue slices for focal abnormalities, from which fragments smaller than 1 mm2 were excised for epoxy embedding. This facilitated TEM identification of intracytoplasmic, budding, 35-40 nm spherical virus particles, confirmed by serology as St. Louis encephalitis. In contrast to mosquitoes and newborn mice, in which high viral loads are associated with minimal tissue responses, these biopsies showed florid angiodestructive inflammation and microgliosis, with rare virions in necrotic perivascular cells and astrocytes. To our knowledge, this represents the first ultrastructural study of St. Louis encephalitis in humans, indicating the potential value of LSCM-aided TEM. ( info) |
3/9. The neurobehavioural consequences of St. Louis encephalitis infection. BACKGROUND: St. Louis encephalitis (SLE) is a relatively common cause of neurological illness, yet little is known about its cognitive and psychosocial consequences. PURPOSE: To describe the cognitive, emotional, psychophysiological, and psychosocial consequences of SLE infection. METHOD: A comprehensive neuropsychological and psychophysiological evaluation of a high functioning woman 6 weeks and 1 year after acute SLE infection is presented. The focus and course of rehabilitation is also examined. RESULTS: The primary cognitive consequences of SLE infection involved attention, working memory, speed of processing, and cognitive efficiency. depression was also observed. Psychometric testing suggested that these deficits largely resolved after 1 year. CONCLUSIONS: SLE produces neurocognitive deficits which are reflected in both psychometric and psychophysiologic measures and functional status. Psychometric and vocational improvement were observed over 1 year. However, the normal vocational return came at a significant psychosocial cost. This case emphasizes the importance of a comprehensive neuropsychological evaluation and illustrates the importance of an integrated rehabilitation programme. ( info) |
| Neurologic illness associated with acute St. Louis encephalitis, West Nile, and Japanese encephalitis virus infection includes acute aseptic meningitis, encephalomyelitis, and a poliomyelitis-like syndrome. Few post-infectious immune-mediated neurologic events associated with flaviviral infection have been reported. The authors report on a woman with apparent post-infectious encephalomyelitis associated with recent St. Louis encephalitis virus infection, suggesting that neurologic illness from flaviviruses may also be seen in the post-infectious period following mild clinical illness. ( info) |
5/9. St. Louis encephalitis in early infancy. We describe a case of St. Louis encephalitis in a 19-day-old infant who presented with fever and seizure activity. To our knowledge, this is the youngest case of St. Louis encephalitis ever reported. ( info) |
6/9. St. Louis encephalitis virus: first isolation from a human in Sao Paulo State, brazil. This paper reports the isolation of St. Louis encephalitis virus (SLEV) from a febrile human case suspected to be dengue, in Sao Pedro, Sao Paulo State. A MAC-ELISA done on the patient's acute and convalescent sera was inconclusive and hemagglutination inhibition test detected IgG antibody for flaviviruses. An indirect immunofluorescent assay done on the C6/36 cell culture inoculated with the acute serum was positive for flaviviruses but negative when tested with dengue monoclonal antibodies. rna extracted from the infected cell culture supernatant was amplified by RT-PCR in the presence of NS5 universal flavivirus primers and directly sequenced. Results of BLAST search indicated that this sequence shares 93% nucleotide similarity with the sequence of SLEV (strain-MSI.7), confirmed by RT-PCR performed with SLEV specific primers. Since SLEV was identified as the cause of human disease, it is necessary to improve surveillance in order to achieve early detection of this agent in the state of Sao Paulo and in brazil. This finding is also an alert to health professionals about the need for more complete clinical and epidemiological investigations of febrile illnesses as in the reported case. SLEV infections can be unrecognized or confused with other ones caused by an arbovirus, such as dengue. ( info) |
| Recent studies have revealed that encephalitis lethargica (EL) may not be related to influenza virus infection but more likely to be a post-infectious autoimmune disease. The diagnostic clinical criteria for EL like illness include subacute hypersomnolence and ophthalmoparesis followed by Parkinsonism, oculogyric crisis, neuropsychiatric disorders and central respiratory abnormality. Recently, magnetic resonance imaging (MRI), which depicts hypersignal intensity on T2 weighted, and FLAIR images at midbrain, tegmentum, and basal ganglia, have been very helpful diagnostic tests in EL like illness. Nevertheless, EL like illness has never been reported in thailand. A 17 year-old man presented with hypersomnolence one week before admission. physical examination revealed drowsiness and ophthalmoparesis. MRI showed bilateral hypersignal intensity lesions on T2 weighted and FLAIR images at midbrain, basal ganglia and temporal lobes. CSF studies showed normal profiles. CSF-PCR for herpes simplex virus, varicella zoster virus, cytomegalovirus, Epstein-Barr virus, Pan-enterovirus and Westnile virus were negative. CSF dengue and Japanese encephalitis virus hemagglutination test were negative. He was treated with intravenous dexamethasone and immunoglobulin. Somnolence and ophthalmoparesis were improved. Two months later, he developed schizophreniform features and Parkinsonism. MRI revealed improvement of midbrain and basal ganglia lesions. CSF studies showed normal CSF profiles while oligoclonal bands were positive. Autoimmune profiles and serological tests for post-streptococcal infection as well as syphilis were negative. thyroid function tests and serum ceruloplasmin were within normal limits. Levo-Dopa, clonazepam and sodium valproate had been prescribed and the clinical syndrome was gradually improved. ( info) |
8/9. St Louis encephalitis with particular involvement of the brain stem. We report a case of St Louis encephalitis in a 4-year-old child in which the main clinical features were dominated by brain stem dysfunction. We document an drome and present a review. We also discuss St Louis encephalitis, with special attention to the ocular manifestations. ( info) |
| arboviruses are mosquitoborne and tickborne agents that persist in nature in complex cycles involving birds and mammals, including humans. Characteristics of arboviral infection include fever, headache, encephalitis, and sometimes death. In 1994, health departments in 20 states reported 100 presumptive or confirmed human cases of arboviral disease to CDC. Of these, 76 were california (CAL) serogroup encephalitis; 20, St. Louis encephalitis (SLE); two, western equine encephalomyelitis (WEE); one, eastern equine encephalomyelitis (EEE); and one, Powassan encephalitis (POW). This report summarizes information about arboviral disease in the united states during 1994. ( info) |