Evaluation of the polymerase chain reaction for diagnosis of herpes simplex virus encephalitis

Cerebrospinal fluid samples from 257 patients with suspected herpes simplex virus encephalitis were prospectively analyzed by herpes simplex virus polymerase chain reaction. The polymerase chain reaction indicated herpes simplex virus encephalitis in 9 serologically proven cases and in 14 additional patients. Increased polymerase chain reaction signals were observed together with more severe neurological symptoms (P < 0.01) and within the first days of acyclovir treatment (P < 0.05).

Molecular evidence for the origin of the widespread Venezuelan equine encephalitis epizootic of 1969 to 1972

Venezuelan equine encephalitis (VEE) virus is a mosquito-borne pathogen that has caused encephalitis in equine species and humans during sporadic outbreaks in the western hemisphere. The last, and most widespread, VEE outbreak occurred in South America, Central America, Mexico and the U.S.A. (Texas) during 1969 to 1972. We have cloned and sequenced the genome of a virulent VEE subtype I-AB virus, strain 71-180, isolated in Texas in 1971. Thirty-four nucleotide differences were detected between the genome of 71-180 virus and that of the subtype I-AB Trinidad donkey (TRD) virus isolated during the 1943 VEE epizootic in Trinidad. Fifteen nucleotide changes occurred in the non-structural genes, 16 in the structural genes and three in the 3' non-coding region. Only six of the nucleotide differences resulted in amino acid substitutions: one change in each of non-structural proteins nsP1 and nsP3, two in the E2 envelope glycoprotein, one in the 6K polypeptide and one in the E1 envelope glycoprotein. The close genetic relationship between 71-180 virus and TRD virus, commonly used for production of formalin-inactivated VEE vaccines, suggests that incompletely inactivated virulent vaccine virus may have been the source of this and other VEE outbreaks. Use of formalized virulent virus was discontinued during the 1969 to 1972 panzootic. No VEE epizootics have been reported since the introduction of the live attenuated TC-83 vaccine virus.

[Epidemiology of encephalitis caused by arbovirus in the Brazilian Amazonia]

An overview of ecological, epidemiological and clinical findings of potential arthropod-borne encephalitis viruses circulating in the Amazon Region of Brazil are discussed. These viruses are the Eastern Equine Encephalitis (EEE), Western Equine Encephalitis (WEE), St. Louis Encephalitis (SLE), Mucambo (MUC) and Pixuna (PIX). These last two are subtypes (III and IV) of Venezuelan Equine Encephalitis virus. The areas of study were the highways and projects of development, as well as places where outbreaks of human diseases caused by arboviruses had been detected. These viruses are widespread in all Amazonia, and at least four of them, EEE, WEE, SLE and MUC are pathogenic to man. EEE and WEE infections were detected by serology, while SLE and MUC by either serology and virus isolation. The PIX virus has the lowest prevalence and, it was isolated in only a few cases, one being from a laboratory infection. Wild birds are the main hosts for all these viruses, except MUC, whose major hosts are rodents. The symptoms presented by infected people were generally a mild febrile illness. Although, jaundice was observed in two individuals from whom SLE was isolated. A comparison of the clinical symptoms presented by the patients in the Amazon Region and other areas of America, especially in the USA is made. In Brazilian Amazon region epidemics have not been detected although, at least, one EEE epizootic was recorded in Bragança, Para State, in 1960. At that time, of 500 horses that were examined 61% were positive to EEE by HI and of them 8.2% died. On the other hand, SLE has caused four epizootics in a forest near Belem. Wild birds and sentinel monkeys were infected, but no human cases were reported.

Astrogliosis in von Economo's and postencephalitic Parkinson's diseases supports probable viral etiology

A marked generalized astrogliosis was observed in the frontal and temporal white matter from a case of von Economo's disease and another of postencephalitic Parkinson's disease, which areas were otherwise devoid of any other demonstrable microscopic lesions. No similar astrocytic reaction of any severity was observed in the same areas in a number of other brain diseases or controls, except when other kinds of lesions were present in the same section, with reactive astrocytes being present within the primary or defining lesion or immediately close by. The marked astrogliosis in von Economo's and postencephalitic Parkinson's diseases in areas "distant" from the primary lesions seeming to indicate extensive pathological involvement, added to the strong qualitative and quantitative similarity of this reaction to that observed in concurrently studied cases of encephalitides caused by the human immunodeficiency virus, lend further factual support to the hypothesis of a viral etiology, albeit unspecified, in both von Economo's and postencephalitic Parkinson's diseases.

[Acute non-suppurative encephalitis in children]

From July 1973 to January 1988, 66 children aged from three months to 14 years, 36 boys and 29 girls, were seen at the Central Hospital, Viborg, with acute encephalitis. In 25 cases the encephalitis was caused by mumps, in eight by measles, in six by chicken pox, one by herpes simplex, one by RS-virus, and one by mycoplasma. One case was seen after vaccination, one after infection and in 22 cases the cause of the encephalitis remained unknown. Sequelae were seen in 17 cases. The risk of encephalitis after mumps, measles, and rubella is an important argument for the use of MMR-vaccination and the risk of encephalitis after chickenpox may justify a vaccination campaign against chickenpox.

Influenza caused epidemic encephalitis (encephalitis lethargica): the circumstantial evidence and a challenge to the naysayers

Circumstantial evidence implicates the influenza virus as the cause of epidemic encephalitis. Arguments used to refute influenza as the causative agent are examined and a challenge is made to naysayers to implicate a viral agent other than influenza.

Serologic prevalence of caprine arthritis-encephalitis virus in California goat dairies

Fifty-three percent of goats in 13 California goat dairies had antibodies to caprine arthritis-encephalitis virus (CAEV), as determined by agar-gel immunodiffusion. Those goat dairies that reared kids on pasteurized milk had a lower seroprevalence than those that did not. Age, rearing kids on unpasteurized milk, and the presence of large joints were associated with antibodies to CAEV. Breed was associated with seroreactivity, but the association was confounded by other factors. Sex was not associated with antibodies to CAEV. The relationship between age and antibodies to CAEV was observed for goats reared on pasteurized or unpasteurized milk, which indicated that continued horizontal (contact) transmission may be important on these dairies and limited the effect of a pasteurized rearing program on control of CAEV infection.

Human and viral gene detection in routine paraffin embedded tissue by in situ hybridisation with biotinylated probes: viral localisation in herpes encephalitis

A simple reproducible protocol for detecting multiple copy human genes and viral DNA in routine formalin fixed paraffin embedded tonsil and brain, by in situ hybridisation with biotinylated probes, is described. The protocol consists of digestion of formalin fixed paraffin sections, with 0.4% pepsin in 0.01 M hydrochloric acid for one hour at 37 degrees C, followed by hybridisation with biotinylated probes. The biotinylated probes used for establishing the conditions for in situ localisation of DNA were total placental DNA (TG1), pHY 2.1 (a Y chromosome probe), and herpes simplex virus I and II. In human male tonsil TG1 labelled all nuclei and pHY 2.1 reacted only with nuclear Y bodies. In herpes encephalitis the virus was detected in some glial cells and neurones.

Experimental La Crosse virus infection of red fox (Vulpes fulva), raccoon (Procyon lotor), opossum (Didelphis virginiana), and woodchuck (Marmota monax)

Susceptibility to infection, resulting viremia and antibody responses, and potential to provide infectious blood meals for Aedes triseriatus were determined and compared for the red fox (Vulpes fulva), raccoon (Procyon lotor), and opossum (Didelphis virginiana) exposed to La Crosse (LAC) virus transmitted by mosquitoes, Ae. triseriatus. Woodchucks (Marmota monax) were infected with LAC virus by needle and syringe. All 5 red foxes became viremic following the bite of a single LAC virus-infected female Ae. triseriatus. Maximum viremia titers were at or above the threshold of infection for Ae. triseriatus in 4 of 5 red foxes for 1-3 days. Biological transmission of LAC virus from infected red foxes to chipmunks (Tamias striatus) was accomplished by Ae. triseriatus. Neutralizing antibody titers in red foxes peaked between day 13 and 27 and were still detectable 3 months post-infection. Woodchucks appear to be efficient amplifiers of LAC virus. Three of 4 inoculated woodchucks became viremic. Maximum viremia titers were consistently above the experimentally determined threshold of infection for Ae. triseriatus. Raccoons and opossums were not as susceptible to LAC virus infection as were red foxes or woodchucks. Only 1 of 5 raccoons became viremic. The viremia titer was low and was detected on only 1 day. Four of 5 raccoons developed LAC virus-neutralizing antibody titers, however. None of the opossums became viremic and only 2 developed LAC virus-neutralizing antibody titers.

California serogroup viruses in New York State: the role of subtypes in human infections

The roles of various subtypes of the California serogroup viruses as infectious agents and as neuropathogens were evaluated by using the plaque reduction neutralization test. Sera from 394 patients with central nervous system (CNS) infections during 1971-1982 and from 501 persons without CNS manifestations were studied. Jamestown Canyon (JC) and La Crosse (LAC) viruses were found to have been common infectious agents in New York State for at least 16 years. JC virus was the prevalent indicated agent in patients with antibody to California serogroup viruses in screening tests (62 of 93 cases), followed by LAC virus (11 cases), snowshoe hare (2 cases), and trivittatus (1 case). In the remaining 17 patients the subtype was undetermined. LAC virus appears to be more pathogenic for children and to produce more serious illness, as judged by the frequent clinical diagnosis of encephalitis. JC virus affects mainly adults, and meningitis was the most common diagnosis. JC virus appears to cause a stronger neutralizing antibody response than does LAC virus, with a longer persistence of high levels of antibody. Some cases of JC virus infection may have been missed in the past due to the choice of a LAC-like isolate from New York State as the sole antigen in hemagglutination-inhibition (HI) screening tests. Comparison of the HI test and a single-dilution neutralization assay for screening for the two major subtypes, JC and LAC, indicated that the latter procedure is more broadly reactive and is less likely to miss cases if only one test antigen is used.

Neutralizing and non-neutralizing monoclonal antibodies to the E2 glycoprotein of Semliki Forest virus can protect mice from lethal encephalitis

Two monoclonal antibodies (UM 4.2 and UM 5.1) directed against the glycoprotein E2 of Semliki Forest virus (SFV) are described; both belong to the IgG2a isotype but are of different idiotype. Analysis employing isoelectric focusing resulted in different focusing patterns for both monoclonals (UM 4.2, pI 8; UM 5.1, pI 7.2). They further differed in their ability to neutralize virus. The UM 4.2 antibodies were inactive in neutralization, while the UM 5.1 antibodies exceeded conventional mouse hyperimmune serum in this respect. Both monoclonal antibodies, however, were able to protect mice passively from a lethal infection with SFV. Based on the amount of protein, the UM 5.1 antibodies were 100-fold more effective than the UM 4.2 antibodies in mouse protection tests.

Acute viral encephalitis: its diagnosis and outcome

Sixty patients with acute viral encephalitis admitted to The London Hospital in the last fifteen years have been reviewed. These consisted of 12 patients with known viral infection, 29 patients with acute viral infection of undetermined type, and 19 patients in whom an encephalitic illness followed a viral infection (post-infection encephalitis). The patients with primary viral encephalitis presented with an inflammatory brain disorder, including headaches and fever, and developed focal or diffuse neurological signs. Patients with post-infection encephalitis, usually following a 'flu'-like illness, presented with an acute neurological disturbance. The results of investigations, including virological studies, CSF examination, electroencephalography and neuroradiology, are described. Biopsy or autopsy material was available in 11 patients and these pathological findings supported the clinical classification of these patients. The mortality was highest in patients with herpes simplex virus encephalitis and lowest in patients with post-infection encephalitis. A considerable morbidity was found, not only in patients with primary viral encephalitis, but also in patients with encephalitis of unknown aetiology and post-infection encephalitis.

Emergence of a new arbovirus disease in Brazil. III. Isolation of Rocio virus from Psorophora Ferox (Humboldt, 1819)

A newly described flavivirus was responsible for a large encephalitis epidemic in São Paulo State, Brazil. The etiologic agent, Rocio virus, was isolated from human patients and sentinel mice. The natural history of the virus is unknown although presumed to be arthropod-borne. Rocio virus was isolated from a single pool containing 19 Psorophora ferox of 47 pools (283 specimens) of this species tested. The positive pool contained 16 deplete, 2 gravid, and 2 engorged mosquitoes. No isolations were made from 2183 pools of other species. The positive pool was collected during the year of the epidemic at the same approximate time and place where vertebrate isolations were made.

[Viral neuraxitis. Further studies of the current epidemiological and clinical aspects]

An epidemiological and clinical investigation upon ten cases of acute viral neuraxitis observed in the country of Alessandria between January 1978 - January 1979, is reported. Four cases of neuraxitis were due to coxsackie B4 virus, two to coxsackie B3, two to influenza type A and one to influenza type B virus, one to rubella and one to varicella-zooster virus. In all the cases blood chemistry, clinical and instrumental examinations (EEgraphy, cerebral scintigraphy and angiography) were coupled with determination of serum levels of complement fixing, haemagglutination inhibiting and neutralizing antibodies on two successive specimens, isolation of virus from cerebrospinal fluid, faeces and pharingeal secretions. Some particularly interesting epidemiological, immunological and clinical features of these neuraxitis are more fully discussed.

Early intrathecal synthesis of interferon in herpes encephalitis

Large quantities of type I interferon were detected in the cerebrospinal fluid (CSF) collected at the onset of herpes encephalitis. This interferon was synthesized intrathecally and disappeared about 10 days after the beginning of neurological signs. In 12 cases of post-eruptive measles encephalitis and in four post-rubella encephalitis, type I interferon was present only in low amounts, or not found at all, even in the CSF collected early. The existence of an intrathecal synthesis of interferon during encephalitis provides a valuable contribution to both the early diagnosis of herpes encephalitis and the study of the pathogenesis of virus infection of the central nervous system (CNS).

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.