[Viral encephalitis virus, a new bioterrorist menace]. / Les virus des encéphalites virales, une nouvelle menace bioterroriste.

Often responsible for little known infections, today viral encephalitis viruses appear as a new bioterrorist menace, because of their easy production and their great pathogenic potential. Spraying is the best way to permit the rapid diffusion of certain encephalitis viruses. Diagnosis of viral encephalitis, predominating in tropical surroundings, is difficult. In the majority of cases, symptoms differ little from those of common flu. With supplementary examinations, the biological abnormalities are usually non-specific. There are no characteristic images on scans or MRI. Identification of the virus in the nasopharynx, blood or cerebrospinal fluid, in serology, PCR or RT-PCR permits confirmation of the virus. Treatment is essentially symptomatic and relies on appropriate reanimation measures. Ribavirin can be indicated in some cases such as the Rift Valley fever, but is formally contraindicated in West Nile encephalitis. The aim of terrorist groups who would use this type of weapon is more to provoke panic and disorganisation than to kill as many people as possible.

Viral encephalitis in England, 1989-1998: what did we miss?

We analyzed hospitalizations in England from April 1, 1989, to March 31, 1998, and identified approximately 700 cases, 46 fatal, from viral encephalitis that occurred during each year; most (60%) were of unknown etiology. Of cases with a diagnosis, the largest proportion was herpes simplex encephalitis. Using normal and Poisson regression, we identified six possible clusters of unknown etiology. Over 75% of hospitalizations are not reported through the routine laboratory and clinical notification systems, resulting in underdiagnosis of viral encephalitis in England. Current surveillance greatly underascertains incidence of the disease and existence of clusters; in general, outbreaks are undetected. Surveillance systems must be adapted to detect major changes in epidemiology so that timely control measures can be implemented.

A new tick-borne encephalitis-like virus infecting New England deer ticks, Ixodes dammini.

To determine if eastern North American Ixodes dammini, like related ticks in Eurasia, maintain tick-borne encephalitis group viruses, we analyzed ticks collected from sites where the agent of Lyme disease is zoonotic. Two viral isolates were obtained by inoculating mice with homogenates from tick salivary glands. The virus, which was described by reverse transcriptase polymerase chain reaction and direct sequencing of the amplification products, was similar to, but distinct from, Powassan virus and is provisionally named "deer tick virus." Enzootic tick-borne encephalitis group viruses accompany the agents of Lyme disease, babesiosis, and granulocytic ehrlichiosis in a Holarctic assemblage of emergent deer tick pathogens.

Tick-borne viral encephalitis in Finland. The clinical features of Kumlinge disease during 1959-1987.

During 1959-1987, 126 patients in Aland Islands and main Finland had serologically verified infections with the virus of tick-borne encephalitis (Kumlinge disease). The most useful test for specific virological diagnosis was haemagglutination inhibition-IgM (HI-IgM). Most cases were from Aland Islands and nearby south-western main Finland. Two of the infections were imported. There were three laboratory infections and two transfusion infections. The disease occurred mainly from July to September. Detailed hospital records of 108 of the patients could be obtained. Ninety-five per cent of the patients had headaches, 82% had lymphocytosis of the cerebrospinal fluid, and 81% had high fever. Forty-four per cent had a confirmed biphasic course of disease. Seventeen per cent were severely ill. There were no deaths. The sequels were psychic irritability and fatigue for up to 1 year. There were eight cases of paresis, two of which became permanent.

Emergence of a new arbovirus disease in Brazil. I. Isolation and characterization of the etiologic agent, Rocio virus.

In April, 1975, an epidemic of human encephalitis was detected in several counties in the State of São Paulo, Brazil; the epidemic continued into 1976. A virus was isolated from central nervous system (CNS) tissues of a 39-year-old male who died on December 8, 1975; the virus was found to be a new flavivirus for which the name Rocio virus is proposed. Nine further isolations of Rocio virus were obtained from CNS tissues of 17 patients who died with clinical symptoms of encephalitis. Isolations of virus and serologic evidence of Rocio virus infection in a significant proportion of the encephalitis patients suggested that Rocio virus was the etiologic agent of the epidemic. Rocio virus was isolated only from patients who died within 5 days of onset of illness. The virus was isolated from two sentinel mice exposed in the epidemic zone and from a rufous collared sparrow (Zonotrichia capensis) collected in the area.

Chromatography of Venezuelan equine encephalomyelitis virus strains on calcium phosphate.

Column chromatography of selected Venezuelan equine encephalomyelitis (VEE) viruses on calcium phosphate gel offered a simple and reproducible method for examination of biochemical characteristics and relatedness of strains within the VEE complex. Members of antigenic subgroup I demonstrated a series of elution profiles within a narrow range of 0.22 to 0.25 M phosphate buffer. Members of antigenic subgroups II, III, and IV differed substantially among themselves and viruses of antigenic subgroup I. These differences in elution behavior may contribute to understanding of observed differences in biological behavior and antigenic variation among VEE viruses.