Detection of herpes-simplex viral genome in brain tissue

Herpes-simplex virus type (HSV-1) nucleic-acid sequences were detected by in-situ hybridisation in thin sections of brains from mice which had been inoculated 24 weeks previously with HSV-1. These mice were not ill, and infectious virus could not be recovered from them. HSV-1 sequences were also present in brain smears from 3 of 4 elderly patients who had died with chronic psychiatric illness and neuropathological changes but not in smears from 2 patients who had had acute psychotic episodes and minimum abnormal histology. Adenovirus type 7 nucleic-acid sequences were not detected in these human specimens.

A hamster-attenuated, temperature-sensitive mutant of Venezuelan encephalitis virus

Pathogenicities of 10 temperature-sensitive mutants of Venezuelan encephalitis virus were studied using the hamster model of human virulence. The parental strain and nine of the temperature-sensitive mutants produced lethal infections in hamsters. Strain ts 126 showed reduced hamster virulence. Deaths with the lethal mutants usually occurred 1 to 3 days later than with parental virus. Nine mutants produced lower levels of viremia than parental virus. Attenuation of ts 126 was related to restriction of viral growth in spleen and probably bone marrow and to absence of the usual pathological lesions in hemopoietic tissues and brain, but was functionally unrelated to temperature sensitivity since temperatures of both normal and infected hamsters remained within the permissive range of the mutant. Deaths did not correlate with titers of the 10 mutants in blood at permissive temperatures or with reversions of four temperature-sensitive mutants to non-temperature-sensitive virus in hamsters.

Arboviruses in New York State: an attempt to determine the role of arboviruses in patients with viral encephalitis and meningitis

In a reveiw of 2,963 patients with signs of infections of the central nervous system in New York State in 1966--1977, arboviruses were found to be the confirmed or presumptive etiologic agents in 60 patients. California encephalitis (CE) virus was the most common (44 patients), followed by Powassan (POW) virus (8), St. Louis encephalitis virus (7), and eastern equine encephalitis (EEE) virus (1). Most patients (47) were children. The incidence of encephalitis was higher in patients with arbovirus findings than in infections with any other of the common neurotropic viruses. The disease was fatal in two patients, one infected with POW virus, the other with EEE virus. Most patients with CE virus infections resided in suburban areas. All POW infections were contracted in six rural counties known for their recreational facilities.

ECHO 25 focal encephalitis and subacute hemichorea

ECHO virus 25 focal encephalitis was documented for the first time in a 5-year-old boy with unequivocal hemichorea. Hemichorea caused by enterovirus CNS disease has never been reported. ECHO virus antigen in cerebrospinal fluid (CSF) cells was demonstrated by the indirect immunofluorescent technique and typed by a significant rise in neutralizing antibodies against ECHO virus 25. Sequential computerized tomographic (CT) studies with digital analysis demonstrated the evolution of a focal process in the head of the left caudate nucleus, ultimately leading to replacement of tissue by a CSF-containing cyst. In the unclarified pathogenesis of cerebral disease in enterovirus infection, this case suggests a focal inflammatory process rather than vasculitis, occlusion, and infarction. Finally, the near-complete recovery of our patient demonstrated that the mere loss of neostriatal tissue was not decisive in itself, because the tissue loss was permanent and the symptoms were transient.

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.

Herpes simplex retinitis

Fatal encephalitis with accompanying retinitis developed in a previously healthy 18-month-old infant. Clinically the disease appeared as whitish-yellow punctate lesions, perivascular cuffing, and hemorrhage. The antibody titer to herpes simplex rose from 1:8 on the day of admission to 1:256 on the day of death. Postmortem, intranuclear inclusion bodies that were typical of those found with herpesvirus were seen in the brain and retina. Viral particles consistent with those of herpesvirus were found by electron microscopy in the brain and in the inner-nuclear and ganglion-nerve fiber layers of the retina. This demonstrates the direct infectious nature of herpetic retinitis. Hematogenous spread of the virus to the retina is presumed.

Viral pathogenesis and molecular biology

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Multicystic cerebral degeneration in neonatal herpes simplex virus encephalitis

Typical herpetic papulovesicular skin lesions developed in an apparently normal infant at 12 days of age and were followed within 48 hours by signs and symptoms of acute encephalitis. Herpes simplex virus type 2 was cultured from the intact skin vesicles, and a fourfold increase in complement fixation titer to herpes simplex virus type 2 was found over the ensuing 24 days. The infant survived her acute illness, but was left with severe neurologic sequelae manifested as microcephaly with multicystic cerebral degeneration. The short-term and convalescent course is documented by serial, clinical, and EEG examinations, and the nature of the cerebral damage is demonstrated by computerized transaxial tomography.

Herpes simplex: a possible cause of brain-stem encephalitis

Herpes simplex virus was isolated from the tracheal aspirate of a 10-year-old boy presenting with acute onset of multiple cranial nerve palsies and a mild right hemiparesis. There was also an elevated herpes complement-fixation titer with decrease in the following weeks infection by herpes virus have been debated, we propose that this represents a case of brain-stem encephalitis due to herpes simplex infection. The importance of early diagnosis and evaluation of therapy are emphasized by this case in which the patient recovered completely.

Cerebrospinal fluid IgG level in herpes simplex encephalitis

Elevated levels of immunoglobulin G (IgG) in the cerebrospinal fluid (CSF) were associated with elevated herpes antibody in the CSF in a case of herpes simplex encephalitis. The case was also characterized by a prolonged course and a difficult virus isolation.

Isolation of Murray Valley encephalitis virus from the brains of three patients with encephalitis

Murray Valley encephalitis virus was isolated from the brains of three patients who died from encephalitis during the 1974 epidemic. Isolation of the virus from autopsy material was successful when death occurred within two weeks of the onset of illness; however, no isolations were made from specimens collected before death or from autopsy material obtained from patients who died more than two weeks after the onset of symptoms. The virus was recovered most frequently in embryonated eggs, but two strains were isolated in cell culture.

Trivittatus virus infections in wild mammals and sentinel rabbits in central Iowa

A serological survey was conducted in Iowa to determine the prevalence rate of California group virus antibodies in sera of several vertebrate species. Serum specimens were assayed for infectivity-neutralizing antibody in a microneutralization system with baby hamster kidney cell culture. Of 77 sera assayed, 21 (27%) neutralized trivittatus (TVT) virus infectivity. The antibody prevalence rate was highest for eastern cottontail rabbits inasmuch as 46% (10/22) of the serum specimens form this species possessed neutralizing activity. Other vertebrate species having TVT virus antibody included the fox squirrel, 29% (7/24), opossum, 12% (3/25), and raccoon, 17% (1/6). One cottontail rabbit serum neutralized both TVT virus and Jamestown Canyon (JC) virus infectivity, and one opossum serum specimen neutralized JC virus. None of the vertebrate sera neutralized La Crosse, St. Louis encephalitis, or western equine encephalomyelitis virus infectivity. Trivittatus virus neutralizing antibody was detected in the sera of sentinel rabbits, and TVT virus was isolated from the blood collected from one of these sentinels shortly after the first population peak of adult Aedes trivittatus mosquitoes in 1973. The implications of these data and the possibility of trans-ovarial transmission of TVT virus in A. trivittatus are discussed.

Cytarabine treatment of herpes simplex encephalitis in infants and small children. A report on three cases with a short review of the literature

Three cytarabine-treated infants and children with herpes simplex encephalitis are presented. The effect of the treatment was excellent in 2 cases. One boy who had a CP syndrome died. It is assumed that the treatment with cytarabine should be started as early as possible with a dosage of 3 mg/kg body weight given intravenously once a day in a single injection for 5 days. No serious side effects have been noted. The advantage of cytarabine over idoxuridine, especially when treating small children and herpetic infections in the central nervous system, are emphasized.

Isolates of California encephalitis (La Crosse) virus from field-collected eggs and larvae of Aedes triseriatus: identification of the overwintering site of California encephalitis

California encephalitis is caused primarily by La Crosse virus, a mosquito-borne agent of which the vector is the mosquito Aedes triseriatus. Once La Crosse virus has been detected in a given geographical area, observations in the same area during subsequent seasons usually have revealed continuing presence of the virus. Field studies were conducted around the homes of children who had had California encephalitis in an effort to define the mechanism by which the virus survived the winter. Eggs and larvae of A. triseriatus collected from natural breeding sites during the springs and summers of 1972-1974 were processed for viral isolation. Collections made during 1972 and 1973 yielded no virus. Eggs, obtained on April 29, 1974 from a basal tree hole of an American elm located approximately 150 feet from the homes of two children who had had California encephalitis in 1970, contained virus, as did larvae aspirated on May 16, 1974, from the same tree hole. This study in Minnesota confirms previous data from Wisconsin and suggests that La Crosse virus may be passed transovarially in A. triseriatus and may overwinter in the diapause stage of eggs.

California encephalitis virus development in mosquitoes as revealed by transmission studies, immunoperoxidase staining, and electron microscopy

Isolates of the snowshoe hare subtype of California encephalitis (CE) virus from Yukon mosquitoes during 1972 and 1973 were transmitted by bites of Aedes aegypti mosquitoes after 4 to 5 weeks of extrinsic incubation at 55 degrees F after intrathoracic injection, and the 1973 strain was transmitted after mosquitoes were fed virus and held for 3 to 4 weeks at 75 degrees F. Antigen of a 1971 isolate of CE virus (Marsh Lake 23) was detected in salivary glands of infected mosquitoes by the immunoperoxidase technique, using highly purified antiserum before and after conjugation with horseradish peroxidase, plus the use of orthotolidine as a substitute for benzidine. enveloped virions 45 nm in diameter were observed in thin sections of salivary glands of Culiseta inornata mosquitoes 59 days after intrathoracic injection with the 1971 isolate, afterincubation at 55 degrees F.