Diagnosis of Fatal Human Case of St. Louis Encephalitis Virus Infection by Metagenomic Sequencing, California, 2016.

We used unbiased metagenomic next-generation sequencing to diagnose a fatal case of meningoencephalitis caused by St. Louis encephalitis virus in a patient from California in September 2016. This case is associated with the recent 2015-2016 reemergence of this virus in the southwestern United States.

[Outbreak of St. Louis encephalitis in the Metropolitan Buenos Aires Area]. / Brote de encefalitis de San Luis en el área metropolitana Buenos Aires.

We describe the epidemiological and clinical findings of 13 patients with diagnosis of infection by St. Louis encephalitis virus, transmitted between January and March 2010 in Buenos Aires Metropolitan Area (AMBA). Thirteen patients, average age 38 years, had an acute onset with hyperthermia and headache. Between days two and ten of the onset of symptoms, 7/13 patients had signs and symptoms of neurological involvement. This was characterized by meningitis without encephalic sings in 1/7 and in 6/7 the most frequent findings were: stiff neck, disorientation, photophobia, confusion and language impairment. Two MR and one EEG revealed signs of involvement of temporal lobes. The cerebrospinal fluid showed pleocytosis with predominance of mononuclear cells, normal glucose and moderately elevated protein. There were no fatalities cases. In 6/13 patients the initial clinical suspicion was dengue. As epidemic virus circulation had not been previously reported in the AMBA it can be considered an outbreak of St. Louis encephalitis for the spatial and temporal clustering of cases.

Brote de encefalitis de San Luis en el Área Metropolitana Buenos Aires / Outbreack of St. Luis encephalitis in the Metropolitan Buenos Aires Area

Se describen los hallazgos epidemiológicos y clínicos de 13 enfermos con diagnóstico de infección por virus de la encefalitis de San Luis, con transmisión entre enero y marzo de 2010, en el Area Metropolitana Buenos Aires (AMBA). Los 13 enfermos, promedio de edad 38 años, tuvieron un comienzo agudo caracterizado por hipertermia y cefalea. Entre los días dos y diez de iniciados los síntomas, 7/13 enfermos tuvieron signos y síntomas de compromiso neurológico caracterizado por meningitis sin signos encefálicos en 1/7. En 6/7 los hallazgos más frecuentes fueron: rigidez de nuca, desorientación temporoespacial, fotofobia, confusión y alteración del lenguaje. Dos resonancias magnéticas y un electroencefalograma presentaron signos de afectación de lóbulos temporales. El líquido cefalorraquídeo se caracterizó por pleocitosis con predominio de células mononucleadas, glucorraquia normal y discreto aumento de proteínas. No hubo casos fatales. En 6/13 pacientes la sospecha clínica inicial fue dengue. Por la agrupación espacial y temporal de los casos puede considerarse un brote epidémico, el primero conocido en el AMBA, ya que no se había notificado previamente la circulación epidémica del virus.

We describe the epidemiological and clinical findings of 13 patients with diagnosis of infection by St. Louis encephalitis virus, transmitted between January and March 2010 in Buenos Aires Metropolitan Area (AMBA). Thirteen patients, average age 38 years, had an acute onset with hyperthermia and headache. Between days two and ten of the onset of symptoms, 7/13 patients had signs and symptoms of neurological involvement. This was characterized by meningitis without encephalic sings in 1/7 and in 6/7 the most frequent findings were: stiff neck, disorientation, photophobia, confusion and language impairment. Two MR and one EEG revealed signs of involvement of temporal lobes. The cerebrospinal fluid showed pleocytosis with predominance of mononuclear cells, normal glucose and moderately elevated protein. There were no fatalities cases. In 6/13 patients the initial clinical suspicion was dengue. As epidemic virus circulation had not been previously reported in the AMBA it can be considered an outbreak of St. Luis encephalitis for the spatial and temporal clustering of cases.

Validation of a microsphere-based immunoassay for detection of anti-West Nile virus and anti-St. Louis encephalitis virus immunoglobulin m antibodies.

A microsphere-based immunoassay (MIA) was previously developed that is capable of determining the presence of anti-West Nile (WN) virus or anti-St. Louis encephalitis (SLE) virus immunoglobulin M (IgM) antibodies in human serum or cerebrospinal fluid. The original data set on which the classification rules were based comprised 491 serum specimens obtained from the serum bank at the Division of Vector-Borne Infectious Diseases of the Centers for Disease Control and Prevention (DVBID). The classification rules were used to provide a result and to determine whether confirmatory testing was necessary for a given sample. A validation study was coordinated between the DVBID and five state health laboratories to determine (i) the reproducibility of the test between different laboratories, (ii) the correlation between the IgM-enzyme-linked immunosorbent assay (MAC-ELISA) and the MIA, and (iii) whether the initial nonspecific parameters could be refined to reduce the volume of confirmatory testing. Laboratorians were trained in the method, and reagents and data analysis software developed at the DVBID were shipped to each validating laboratory. Validating laboratories performed tests on approximately 200 samples obtained from their individual states, the collections of which comprised approximately equal numbers of WN virus-positive and -negative samples, as determined by MAC-ELISA. In addition, 377 samples submitted to the DVBID for arbovirus testing were analyzed using the MIA and MAC-ELISA at the DVBID only. For the specimens tested at both the state and the DVBID laboratories, a correlation of results indicated that the technology is readily transferable between laboratories. The detection of IgM antibodies to WN virus was more consistent than detection of IgM antibodies to SLE virus. Some changes were made to the analysis software that resulted in an improved accuracy of diagnosis.

Encephalitis lethargica like illness: case report and literature review.

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.

Use of immunoglobulin m cross-reactions in differential diagnosis of human flaviviral encephalitis infections in the United States.

To define the virus specificity of the immunoglobulin M (IgM) antibody-capture enzyme-linked immunosorbent assay (MAC-ELISA) among the medically important members of the Japanese encephalitis (JE) virus serocomplex of flaviviruses, 103 IgM-positive human serum samples from patients with confirmed West Nile (WN) virus, St. Louis encephalitis (SLE) virus, or JE virus infections were assembled and simultaneously tested against all three viral antigens in a standardized MAC-ELISA. Of the serum samples tested, 96 (93%) showed higher positive-to-negative absorbance ratios (P/Ns) with the infecting virus antigen compared to those obtained with the other two virus antigens. Of the seven specimens with higher P/Ns with heterologous virus antigens, six were from patients with SLE virus infections (the serum samples had higher levels of reactivity with WN virus antigen) and one was from a patient with a JE virus infection (this serum sample also had a higher level of reactivity with WN virus antigen). Not surprisingly, similar virus specificity was observed with WN virus-elicited IgM in cerebrospinal fluid. As shown in previous studies, a subset of these specimens was even less reactive in the MAC-ELISA with dengue virus, a member of a different flavivirus serocomplex. The degree of virus cross-reactivity did not appear to be related to days postonset, at least during the first 40 days of infection. Infections with WN virus could be correctly distinguished from infections with SLE virus on the basis of the observed anti-viral IgM cross-reactivities alone 92% of the time. Infections with SLE virus resulted in antibody that was more cross-reactive, so identification of SLE virus as the infecting agent by use of MAC-ELISA cross-reactivity alone was more problematic.

St. Louis encephalitis--Florida 1977. Patterns of a widespread outbreak.

From 8 August through 5 December 1977, 110 laboratory-documented cases (78 confirmed, 32 presumptive) of St. Louis encephalitis (SLE) occurred in 20 counties throughout central-south Florida. Most cases were initially identified through an active surveillance system involving repeated contact of hospital infection control officers. This outbreak had three characteristics that are unusual for SLE epidemics in the eastern United States: it lacked an urban focus, a disproportionate number of cases affected young males, and the epidemic period extended into December. There was no significant difference between attack rates for blacks and whites. Males were significantly more often affected than females. Because of the time required for laboratory confirmation of cases, most outbreak control measures were initiated after the outbreak was declining. Reporting of clinically suspected SLE cases to initiate epidemic mosquito control should improve the timeliness of control measures in future outbreaks.

St Louis encephalitis in Ohio, September 1975: clinical and EEG studies in 16 cases.

In 1975, during the largest epidemic of St Louis encephalitis (SLE) in the United States, 416 cases were diagnosed in Ohio. Persons who were admitted to two Columbus (Ohio) hospitals with suspected acute viral CNS infection were prospectively studied to define the virologic and clinical aspects of SLE. Sixteen cases of SLE were diagnosed serologically. Fifteen patients had signs of encephalitis and one had aseptic meningitis. Six patients had the syndrome of inappropriate antidiuretic hormone secretion. Other frequent findings included moderate peripheral leukocytosis and CSF pleocytosis, with mild elevation of CSF protein levels but normal glucose levels. Severe neurologic sequelae were infrequent. The EEG proved valuable in diagnosis and prognosis. Results of brain scans were normal. Virus in CSF or urine was not demonstrated, nor was viral antigen in CSF or urine sediments. Specific antibody was found in the sera and CSF of all patients who were tested, but interferon was not detected.