Use of Testing for West Nile Virus and Other Arboviruses.

In the United States, the most commonly diagnosed arboviral disease is West Nile virus (WNV) infection. Diagnosis is made by detecting WNV IgG or viral genomic sequences in serum or cerebrospinal fluid. To determine frequency of this testing in WNV-endemic areas, we examined the proportion of tests ordered for patients with meningitis and encephalitis at 9 hospitals in Houston, Texas, USA. We identified 751 patients (567 adults, 184 children), among whom 390 (52%) experienced illness onset during WNV season (June-October). WNV testing was ordered for 281 (37%) of the 751; results indicated acute infection for 32 (11%). Characteristics associated with WNV testing were acute focal neurologic deficits; older age; magnetic resonance imaging; empirically prescribed antiviral therapy; worse clinical outcomes: and concomitant testing for mycobacterial, fungal, or other viral infections. Testing for WNV is underutilized, and testing of patients with more severe disease raises the possibility of diagnostic bias in epidemiologic studies.

Medical and molecular perspectives into a forgotten epidemic: encephalitis lethargica, viruses, and high-throughput sequencing.

The emergence of encephalitis lethargica (EL), an acute-onset polioencephalitis of unknown etiology as an epidemic in the years 1917-1925 is still unexplainable today. Questioned by the first descriptor of EL himself, Constantin von Economo, there has been much debate shrouding a possible role of the "Spanish" H1N1 influenza A pandemic virus in the development of EL. Previous molecular studies employing conventional PCR for the detection of influenza A virus RNA in archived human brain samples from patients who died of acute EL were negative. However, the clinical and laboratory characteristics of EL and its epidemiology are consistent with an infectious disease, and recently a possible enterovirus cause was investigated. With the rapid development of high-throughput sequencing, new information about a possible viral etiology can be obtained if sufficient specimens for analysis were still available today. Here, we discuss the implications of these technologies for the investigation of a possible infectious cause of EL from archived material, as well as a prospectus for future work for acquiring viral nucleic acids from these sources.

Fiebre del nilo del oeste (west nile fever): una nueva amenaza de los viejos continentes / West Nile fever : a new threat of old continents

La Fiebre del nilo del oeste (WNF) ha sido conocido en los viejos continentes, desde hace 70 años. El virus fue aislado en Uganda por primera vez en 1937. Brotes de esta enfermedad han ocurrido en Israel desde 1950 involucrando a más del 60 por ciento de la población. Han ocurrido brotes también en el sur de Europa y Asia. La infección fue documentada por primera vez en el hemisferio occidental en ocasión de un brote de encefalitis en New York; siendo documentada serológicamente en 236 de 290 pacientes con síntomas agudos. ¿Qué interés y relación tiene esta antigua infección viral con los países latinoamericanos? Se demostró que este virus es transmitido entre aves salvajes por los mosquitos culex. Y los pájaros migratorios podrían fácilmente distribuir esta infección a Honduras. Durante los meses de verano, puede encontrarse el vector, culex pipiens en Honduras, lo mismo que los mosquitos aedes y anopheles que han sido asociados con WNF. Más aún, las características clínicas son muy similares a nuestras epidemias actuales de dengue. El virus fue documentado en Norteamérica, y las condiciones son apropiadas para su diseminación en el hemisferio Occidental. Es el propósito principal de este artículo, por lo tanto, brindar una actualización en este y otros aspectos del WNF al médico latinoaméricano

The Gordon Wilson lecture: unique interactions between viruses, neurons and the immune system.

The increased susceptibility of young individuals to alphavirus encephalitis is likely to be linked to the ease with which immature neurons are induced to undergo apoptosis after infection. In the more mature individuals, virus infection of neurons may not lead to apoptosis and in the absence of an effective immune response persistent infection is established. The major mechanism by which alphavirus infection of neurons is controlled is by production and local secretion of antibody to the surface glycoproteins. Antibody acts synergistically with interferon to decrease intracellular virus replication but does not eliminate the infected cell or the viral RNA within the cell. Therefore, the immune response controls, but does not cure the infection, leading to a requirement for long-term local synthesis of antiviral antibody in the CNS. For the host persistent intracellular RNA and need for longterm control is probably a reasonable price to pay for a noncytolytic mechanism for control of neuronal viral infection.

Viral infections in the intensive care unit.

Serious viral infections requiring intensive care generally occur in immunocompromised patients and in those patients with underlying cardiopulmonary disease. However, occasional cases may occur in normal hosts. This article reviews the serious viral diseases that are commonly encountered in the adult ICU, including viral pneumonia, encephalitis, and hepatitis, and focuses on diagnostic techniques and management principles. A separate section is devoted to cytomegalovirus infection, given the prominent role that this virus plays in the immunocompromised host receiving intensive care.

Viral encephalitis.

Viral encephalitis represents an important source of morbidity and mortality worldwide. Numerous viruses possess neurovirulence, producing encephalitic disorders that usually consist of fever, headache, vomiting, altered consciousness, focal or generalized seizures, and motor dysfunction. Contemporary virologic methods frequently allow rapid and specific identification of viral pathogens, but the etiologic agent remains uncertain in 25% or more of encephalitis patients. Although acyclovir substantially reduces mortality and improves outcome for patients with herpes simplex virus encephalitis, supportive care remains the only therapy available for most patients with virus encephalitis.

[Von Economo-Cruchet lethargic encephalitis and its relation to HIV infection]. / L'encéphalite léthargique de von Economo-Cruchet et ses rapports avec l'infection HIV.

The AIDS epidemic is currently considered to be the first retroviral disease in humans. However, in the large volume of work on von Economo-Cruchet's encephalitis lethargica, the authors reveal a series of common points between both diseases. The progress of both diseases is identical at every stage, with neurotropism, premature psychological disorders, mononucleasic syndrome, similar somatic manifestations of the viral attack and terminal dementia. The anatomo-pathological and epidemiological data, along with the hypothesis that encephalitis lethargica is sexually transmitted, reinforce the idea of a relationship between the two diseases. The interest which would be aroused by the discovery of a viral origin of encephalitis lethargica and the resulting experimental elements seem to make it worthwhile leaving the question open in order to find a precise answer. We are calling on all our colleagues in basic research to seek a solution to what we think is an essential question.

[Chronic fatigue syndrome--a new disease picture?]. / Das Chronic-fatigue-Syndrom--Ein neues Krankheitsbild?

The chronic fatigue syndrome has recently been more frequently diagnosed. Yet it is unknown if this syndrome represents a disease entity of its own or merely a diagnostic label for a miscellaneous group of disorders. Further investigations are needed to find out if the syndrome has an organic or psychosomatic aetiology, or a mixture of both. In the meantime it is the responsibility of the clinician to make this decision in each individual case.

[The clinico-laboratory characteristics of cases of diseases connected with viruses of the California encephalitis complex in the inhabitants of Moscow]. / Kliniko-laboratornaia kharakteristika sluchaev zabolevanii, sviazannykh s virusami kompleksa kaliforniiskogo éntsefalita, u zhitelei Moskvy.

To study the role of viruses of the California encephalitis virus complex (the family Bunyaviridae) in infectious pathology, 187 fever patients admitted to the Clinical Infectious Hospital in May-September 1986 were examined. In 10 of these patients the neutralization test revealed the presence of diagnostically significant changes in neutralizing antibodies (neutralization indices), which was indicative of the role played by Tahyna virus or other related viruses belonging to the California encephalitis virus complex in the etiology of the diseases. The analysis of the clinical picture showed that in all patients the disease took an acute course in its initial stage, starting with shivering and characterized by high fever, headache, pronounced toxicosis, the possibility of the formation of intracerebral hypertension and pneumonia.

[Treatment of neurological forms of Argentinian hemorrhagic fever with cytarabine]. / Traitement des formes nerveuses de la fièvre hémorragique argentine par la cytarabine.

The effects of cytarabine on neurological forms of Argentina Hemorrhagic Fever were evaluated in 125 patients. The mortality was 12.88 per cent compared to 61.40 per cent in untreated patients. (p less than 0.0001). The efficiency of this treatment depends on its early application. No side effect was observed.

The pathogenesis of acute viral encephalitis and postinfectious encephalomyelitis.

Japanese encephalitis and postmeasles encephalomyelitis represent two important forms of acute encephalitis in the developing world. Japanese encephalitis accounts for 20,000 acute illnesses per year, and measles encephalomyelitis accounts for as many as 100,000. Both are accompanied by mortalities of 20%-30%, and in both forms, approximately one-half of the survivors have neurological sequelae. Therefore, these two diseases are responsible for a considerable proportion of worldwide mental and motor disabilities. Furthermore, both diseases are preventable with use of safe vaccines. Despite these similarities, their very different pathologies appear to be based on different mechanisms of pathogenesis (table 2). In Japanese encephalitis there is direct invasion of the virus into the nervous system, selective infection and destruction of neurons, and evidence that both humoral and cellular immune responses attenuate the infection. In measles encephalomyelitis there is little evidence that the virus invades the nervous system. Rather, measles virus infects lymphoid cells and causes abnormalities in immune regulation. Humoral immune responses are not found within the nervous system, and the cellular immune response may be inappropriately directed against host antigens. In measles encephalomyelitis, the inflammatory cells entering the nervous system may be the effector cells of autoimmune disease.

Non-herpes simplex encephalitis is early exclusion of herpes simplex etiology possible?

Since effective antiviral treatment is available for herpes simplex encephalitis (HSE), early diagnosis or exclusion of herpes simplex etiology is essential for prognosis. In a retrospective study of 25 cases of acute viral encephalitis not caused by herpes simplex virus (non-HSE), we investigated whether HSE can be excluded in the early phase before serological evidence is present. Using clinical means, history, investigations of CSF (protein, cells), EEG, and CCT, HSE could not be excluded with reliability. This is because clinical signs and laboratory results are not pathognomonic for any form of viral encephalitis, even if periodic activity in EEG and temporal attenuation in CCT are more frequent in HSE than in other forms of encephalitis. Therefore, in all cases of severe encephalitis, acyclovir therapy should be initiated early.