A nationwide outbreak of Reye's Syndrome. Its epidemiologic relationship of influenza B

Neurologic aspects of influenza viruses

Although influenza A and B viruses are primarily known as respiratory viruses and mainly infected only the upper respiratory tract in humans, patients with influenza often develop signs and symptoms that are not due to the respiratory system. Frequently individuals with influenza develop headaches, meningismus, and even seizures in addition to their typical respiratory symptoms. In the past decades, influenza viruses have also been associated with serious non-respiratory signs. The famous 1918 strain of influenza was associated with von Economo's encephalitis lethargica and postencephalitic parkinsonism. In the 1960s influenza virus infections in children were associated with Reye's syndrome characterized often by fatty non-inflammatory hepatic disease and an encephalopathy with marked non-inflammatory cerebral edema. Intermittently children with influenza develop focal myalgia and myositis. Guillain–Barré syndrome was epidemiologically associated with the 1978 killed influenza vaccine but not subsequent vaccines. Although occasional children with influenza have developed encephalopathy, from 2000 through 2004 there was an increase in the number of serious cases of acute necrotizing encephalopathy accompanying infection with the influenza A 2009 strain. The current H5N1 strain of bird influenza occasionally infects humans with a high mortality rate and some appear to have central nervous signs. This chapter explores what is known about these influenza neurologic associations.

Reye's or Reye's-like syndrome in western lowland gorilla (Gorilla gorilla gorilla)

BACKGROUND

A 15-year-old western lowland gorilla (Gorilla gorilla gorilla) died shortly after transfer to the North Carolina Zoo.

METHODS

Complete blood count, serum biochemical analysis, and necropsy were performed.

RESULTS

Combination of compatible clinical signs, biochemical and histopathological findings fulfilled all of the CDC definition criteria of Reye's or a Reye's like syndrome.

CONCLUSIONS

This report describes a case of Reye's syndrome or Reye's-like syndrome in a non-human primate.

Preparation and characterization of egg yolk immunoglobulin Y specific to influenza B virus

The aim of this study was to prepare egg yolk immunoglobulin (IgY) for use in the prevention and treatment of influenza B viral infections. Laying hens were immunized with inactivated influenza B virus (IBV), and IgY was isolated from the egg yolk by multiple polyethylene glycol (PEG) 6000 extraction and ammonium sulfate purification steps. The titers and specificity of the purified antibodies were assessed. The specific IgY titer increased beginning the second week after the first immunization, with the titer peaking at the fifth week. The yield of IgY was 76.5mg per yolk, and the purity was 98.2%. The use of western blotting and the hemagglutination inhibition (HI) test demonstrated that IBV-specific IgY binds specifically to influenza B virus proteins, and a plaque reduction assay revealed the neutralization efficacy of IBV-specific IgY at reducing influenza infection in MDCK cells. Furthermore, when mice were treated intranasally prior to or after influenza B virus infection, IBV-specific IgY protected the mice from influenza infection or reduced viral replication in their lungs, respectively. These findings indicate that IgY is an easily prepared and rich source of antibodies that offers a potential alternative strategy for preventing and treating influenza B infections.

Fatal case of Reye's syndrome associated with H3N2 influenza virus infection and salicylate intake in a 12-year-old patient

We describe a fatal case of Reye's syndrome in a 12-year-old male patient during an influenza A (H3N2) infection for which he received salicylates. In the current situation of the novel A/H1N1 virus pandemic, we believe that it is of high importance to emphasize the risks associated with salicylate intake to avoid the reappearance of Reye's syndrome.

Live, attenuated influenza virus (LAIV) vehicles are strong inducers of immunity toward influenza B virus

Historically, vaccines developed toward influenza viruses of the B type using methodologies developed for influenza A viruses as a blueprint have not been equally efficacious or effective. Because most influenza research and public attention concerns influenza A viruses, these shortcomings have not been adequately addressed. In this manuscript, we utilized different influenza vaccine vehicles to compare immunogenicity and protection in mice and ferrets after vaccination against an influenza B virus. We report that plasmid DNA vaccines demonstrate low immunogenicity profiles and poor protection compared to either whole, inactivated influenza virus (IIV) or, live, attenuated influenza virus (LAIV) vaccines. When mixed prime:boost regimens using LAIV and IIV were studied, we observed a boosting effect in mice after priming with LAIV that was not seen when IIV was used as the prime. In ferrets LAIV induced high antibody titers after a single dose and provided a boost in IIV-primed animals. Regimens including LAIV as a prime demonstrated enhanced protection, and adjuvantation was required for efficacy using the IIV preparation. Our results differ from generally accepted influenza A virus vaccine models, and argue that strategies for control of influenza B virus should be considered separately from those for influenza A virus.

Essential sequence of influenza B virus hemagglutinin DNA to provide protection against lethal homologous viral infection

Hemagglutinin (HA) is the main surface glycoprotein of influenza B virus. The B/Ibaraki/2/85 virus HA gene is 1758 bp in length, including signal peptide sequence, HA1 sequence, and HA2 sequence. We previously proved that B/Ibaraki/2/85 HA DNA induced immune response and provided effective protection in mice against challenge with homologous virus. In this study, a series of recombinant plasmids encoding truncated HA gene were constructed by PCR. BALB/c mice were immunized with the plasmids and challenged with a lethal dose of homologous virus. The essential sequence of HA DNA against influenza virus was explored by evaluation of survival rate, lung virus titer, bodyweight change, and serum anti-HA antibody titer of mice. The result showed that serial deletion did not deprive HA DNA of its protective ability until 885 nucleotides (295 amino acids) at 3'-terminal or 9 nucleotides of the signal peptide sequence at 5'-terminal were deleted. When the signal peptide sequence was kept intact and the 5'-terminal deletion started at the beginning of the HA1 sequence, deletion of 51 nucleotides (17 amino acids) made HA DNA lose its protective ability. This suggests that the sequence nt94-876 of B/Ibaraki/2/85 virus HA DNA played an important role in protection against infection.

Influenza virus and CNS manifestations

Neurological involvement during influenza infection has been described during epidemics and is often consistent with serious sequelae or death. An increasing incidence of influenza-associated encephalitis/encephalopathy has been reported in Japan, mainly in children. A variety of other clinical CNS manifestations, such as Reye's syndrome, acute necrotising encephalopathy (ANE), and myelitis as well as autoimmune conditions, such as Guillain-Barre's syndrome, may occur during the course of influenza infection. Virological diagnosis is essential and based on virus isolation, antigen detection, RNA detection by PCR, and serological analyses. Neuroimaging with CT and MRI of the brain are of prognostic value. The pathogenic mechanisms behind the influenza CNS complications are unknown. The treatment is symptomatic, with control of vital functions in the intensive care unit, antiepileptic medication and treatment against brain oedema.

Protection against influenza B virus infection by immunization with DNA vaccines

Protection against a lethal influenza B virus infection was examined in BALB/c mice immunized with plasmid DNAs encoding hemagglutinin (HA), neuraminidase (NA and NB) and nucleoprotein (NP) from the B/Ibaraki/2/85 virus. Each DNA vaccine was administered twice, 3 weeks apart, at a dose of 1 microg per mouse by particle-mediated DNA transfer to the epidermis (gene gun) or at a dose of 30 microg per mouse by electroporation into the muscle. Three weeks after the second vaccination, the mice were challenged with a lethal dose of homologous virus. HA and NA DNAs conferred complete protection against the lethal viral challenge, whereas NB and NP DNAs failed to provide protection against infection. Furthermore, protection in different strains of mice, BALB/c, B10 and C3H, immunized with HA and NA DNAs was compared. Both HA and NA DNAs conferred complete protection against the lethal challenge in all the tested mouse strains. These results suggest that both the HA and NA molecules can be used as vaccine components to provide effective protection against influenza B virus infection.

Chronic sodium salicylate treatment exacerbates brain neurodegeneration in rats infected with Trypanosoma brucei

We have reported previously that axonal degeneration in specific brain regions occurs in rats infected with the parasite Trypanosoma brucei. These degenerative changes occur in spatiotemporal association with over-expression of pro-inflammatory cytokine messenger RNAs in the brain. To test how aspirin-like anti-inflammatory drugs might alter the disease process, we fed trypanosome-infected rats with 200mg/kg of sodium salicylate (the first metabolite of aspirin) daily in their drinking water. Sodium salicylate treatment in uninfected rats did not cause any neural damage. However, sodium salicylate treatment greatly exacerbated neurodegeneration in trypanosome-infected rats, resulting in extensive terminal and neuronal cell body degeneration in the cortex, hippocampus, striatum, thalamus, and anterior olfactory nucleus. The exaggerated neurodegeneration, which occurred in late stages of infection, was temporally and somewhat spatially associated with a late-appearing enhancement of messenger RNA expression of interleukin-1beta, interleukin-1beta converting enzyme, tumor necrosis factor-alpha, and inhibitory factor kappaBalpha in the brain parenchyma. Restricted areas showed elevations in messenger RNA expression of interleukin-1 receptor antagonist, interleukin-6, inducible nitric oxide synthase, interferon-gamma, and inducible cyclooxygenase. The association suggests that increased production of pro-inflammatory cytokines in the brain may be an underlying mechanism for neural damage induced by the chronic sodium salicylate treatment. Furthermore, the results reveal a serious complication in using aspirin-like drugs for the treatment of trypanosome infection.

Reye's syndrome in the United States from 1981 through 1997

BACKGROUND

Reye's syndrome is characterized by encephalopathy and fatty degeneration of the liver, usually after influenza or varicella. Beginning in 1980, warnings were issued about the use of salicylates in children with those viral infections because of the risk of Reye's syndrome.

METHODS

To describe the pattern of Reye's syndrome in the United States, characteristics of the patients, and risk factors for poor outcomes, we analyzed national surveillance data collected from December 1980 through November 1997. The surveillance system is based on voluntary reporting with the use of a standard case-report form.

RESULTS

From December 1980 through November 1997 (surveillance years 1981 through 1997), 1207 cases of Reye's syndrome were reported in patients less than 18 years of age. Among those for whom data on race and sex were available, 93 percent were white and 52 percent were girls. The number of reported cases of Reye's syndrome declined sharply after the association of Reye's syndrome with aspirin was reported. After a peak of 555 cases in children reported in 1980, there have been no more than 36 cases per year since 1987. Antecedent illnesses were reported in 93 percent of the children, and detectable blood salicylate levels in 82 percent. The overall case fatality rate was 31 percent. The case fatality rate was highest in children under five years of age (relative risk, 1.8; 95 percent confidence interval, 1.5 to 2.1) and in those with a serum ammonia level above 45 microg per deciliter (26 micromol per liter) (relative risk, 3.4; 95 percent confidence interval, 1.9 to 6.2).

CONCLUSIONS

Since 1980, when the association between Reye's syndrome and the use of aspirin during varicella or influenza-like illness was first reported, there has been a sharp decline in the number of infants and children reported to have Reye's syndrome. Because Reye's syndrome is now very rare, any infant or child suspected of having this disorder should undergo extensive investigation to rule out the treatable inborn metabolic disorders that can mimic Reye's syndrome.

Chapter 25 Respiratory tract viruses

Respiratory tract infections are among the commonest of illnesses, and most individuals will experience two to five infections during each year of their lives. The illnesses vary from relatively mild common colds caused by rhinoviruses and coronaviruses, to severe bronchiolitis and pneumonia caused by adenoviruses and influenza viruses and respiratory syncytial virus (RSV) in infants: the former is associated with little morbidity and no mortality, while influenza is responsible annually for between 1 and 25 thousand deaths per 50 million population. Over 140 viruses cause respiratory tract infections, with the added complications of influenza viruses where new antigenic variants are recognized almost annually; and immunity to infection by one virus strain offers little or no protection to infection by others. Knowledge of the mechanisms of spread of respiratory viruses is largely understood and has helped in infection control; however, the clinical signs and symptoms of infection tend not to be diagnostic of the causative agent; and although vaccines have been developed for the more serious infections such as influenza and some adenovirus infection, none are available for other important infections. Treatment is largely symptomatic, but the compounds ribovirin for RSV infection and amantadine for influenza virus infection have been shown to be effective. Much remains to be discovered before more effective measures can be implemented to limit the enormous costs incurred by these infections. The number of viruses involved is large, and the spectrum of illness complex: in the present chapter, the viruses are described, together with the features of the epidemiology, pathogenesis, clinical disease, and treatment.

Reye's syndrome

Reye's syndrome is a rare disorder appearing almost always in childhood. It is characterized by acute encephalopathy and fatty degeneration of the viscera. The mortality is high and many survivors have neurologic sequelae. A viral illness, particularly varicella or influenza B, usually precedes the syndrome. It has been associated with the use of aspirin during such infections. The number of cases has declined in countries where there has been a public education campaign and aspirin products have been withdrawn from sale. It is suggested that the same campaign is initiated in Denmark.

Pharmacokinetic profile of dodecanedioic acid, a proposed alternative fuel substrate

Dodecanedioic acid (C12), a saturated, aliphatic dicarboxylic acid with 12 carbon atoms, was given as an intravenous bolus (800 mumol/kg of body weight [kgBW]) in male Wistar rats to study its pharmacokinetic profile. Because total plasma C12, which results from the sum of both free and albumin binding fractions, was measured by high-performance liquid chromatography, an in vitro experimental session was carried out to determine the binding curve of C12 in rat plasma. These data were then used to calculate the plasma C12 free fraction in in vivo experiments. The best fit obtained for the experimental data of albumin binding was obtained with the equation of reversible, saturable binding to one, two, or three classes of noninteracting equivalent sites. Only a single binding site was clearly identified with a dissociation constant of 147 mumol/L and a maximal predicted binding of 1.57 mol/mol albumin. The urinary excretion of C12 was 3.90 +/- 1.62% of the administered dose. The pharmacokinetic analysis was performed by one-compartment model with linear transfer to the tissues, taking into account simultaneously both plasma concentration and urine excretion data. The apparent volume of distribution of C12 was 0.248 +/- 0.035 L/kgBW, the apparent first order rate constant to the tissues was 0.0535 +/- 0.0123 min-1 and that from plasma to urine was 0.00206 +/- 0.00051 min-1. The C12 plasma half-life was 12.47 minutes. Renal clearance was 0.00051 L/kgBW per minute, whereas the systemic clearance was 0.0138 L/kgBW per minute. Because the renal clearance was much less than the rat inulin clearance reported in literature, the presence of C12 passive back-diffusion was hypothesized.

Experimental study on Reye's syndrome: inhibitory effect of interferon alfa on acetylsalicylate-induced injury to rat liver mitochondria

Viral infection and acetylsalicylate (ASA)-induced mitochondrial aberration have been reported to play important roles in the pathogenesis of Reye's syndrome. We report that increasing amounts of ASA (0 to 250 mumol/L) resulted in increases in state 4 respiration and decreases in state 3 respiration in rat liver mitochondria in vitro when using alpha-ketoglutarate and/or beta-hydroxybutyrate as respiratory substrates, but not when using succinate as substrate. Interferon alfa (IFN-alpha) (1.5 to 5 x 10(4)IU/mL, approximately 1/100 the therapeutic dosage for humans) and interleukin-1 (IL-1) (1.5 to 2 x 10(4)IU/mL, nearly equivalent to the therapeutic dosage) decreased the severity of the above effects via interaction with mitochondrial membranes. Interferon gamma (IFN-gamma) and interleukin-2 (IL-2) had no such protective effect. Electron microscopic observation indicated that IFN-alpha prevented the induction of mitochondrial swelling by ASA. These results suggest that IFN-alpha may prove to be effective for the treatment of Reye's syndrome.

Role of influenza B virus in hepatic steatosis and mitochondrial abnormalities in a mouse model of Reye syndrome

The hepatic steatosis observed in the influenza B virus mouse model of Reye syndrome has been attributed to infectious virus or, alternately, to decreased food intake in the virus-treated mice or impurities in the virus preparation. To resolve this issue, 4- to 6-wk-old male Balb C mice were given, by intravenous injection, 12,800 hemagglutination units of influenza B Lee/40 virus in phosphate buffered saline/1% bovine serum albumin using virus prepared by ultra-centrifugation from infected allantoic fluid, by sucrose density-gradient purification of virus prepared by ultracentrifugation from infected allantoic fluid or by irradiation of virus prepared by ultracentrifugation from infected allantoic fluid to inactivate virus. The infectivity titer of virus prepared by ultracentrifugation from infected allantoic fluid was much higher than that of sucrose density-gradient purified virus prepared from infected allantoic fluid: 50% egg infectious dose for virus prepared by ultracentrifugation from infected allantoic fluid was 3.9 x 10(4)/hemagglutination unit vs. 8.7 50% egg infectious dose/hemagglutination unit for sucrose density-gradient purified virus prepared from infected allantoic fluid. Control mice received phosphate-buffered saline/1% bovine serum albumin or uninfected allantoic fluid diluted in phosphate-buffered saline/1% bovine serum albumin. Mice were fasted to eliminate dietary variation, and livers were obtained 36 hr after virus administration. Of the above treatments, only virus prepared by ultracentrifugation from infected allantoic fluid caused clinical illness and increased hepatic triglycerides (p less than 0.02) compared with controls. Hepatic triglycerides in virus prepared by ultracentrifugation from infected allantoic fluid correlated with histopathological vacuolization scores (r = 0.5773; p less than 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Cross-protection against influenza B type virus infection by intranasal inoculation of the HA vaccines combined with cholera toxin B subunit

The relationship between the antibody responses to various influenza B type virus HA vaccines and protection against live B virus infection was investigated in Balb/c mice which had been inoculated intranasally with a combination of the HA vaccines and B subunit of cholera toxin (CTB) 4 weeks previously. The inoculation of HA vaccine, prepared from B/Ibaraki/2/85 (B/Ibaraki), B/Nagasaki/1/87 (B/Nagasaki) or B/Aichi/5/88 (B/Aichi) viruses, combined with CTB induced high levels of both nasal IgA and serum HI antibodies to any of B/Ibaraki, B/Nagasaki and B/Aichi viral antigens. Simultaneous inoculation of each CTB-combined HA vaccine provided complete protection against B/Ibaraki virus infection which is demonstrated by both rapid clearance of pulmonary virus and complete survival. On the other hand, the inoculation of HA vaccine prepared from B/Yamagata/16/88 (B/Yamagata) virus together with CTB induced only a low level of nasal IgA antibodies, cross-reactive to B/Ibaraki, B/Nagasaki and B/Aichi viral antigens and protected only partially against B/Ibaraki virus challenge. The involvement of the B type virus-specific immunity in this protection was suggested by the absence of protection against B/Ibaraki virus infection in mice previously inoculated with both A/PR/8/34 (H1N1) virus HA vaccine and CTB. These results suggest that antibodies to various influenza B viruses are cross-reactive to each B type virus antigens and that cross-protection against B virus infection could be conferred depending on the degree of B type virus cross-reactive immunity including secretory IgA antibodies.

Reye and Reye-like syndromes: results of a pilot study in Peninsular Malaya, 1986

A pilot epidemiologic study of all cases of Reye and Reye-like syndromes was undertaken at 8 representative major hospitals in Peninsular Malaya from January 1st to December 31st 1986. The cases were classified as definitive Reye's syndrome, clinical Reye's syndrome and encephalo-hepatopathies. Less than 50% of cases reviewed fulfilled the National Center for Disease Control criteria for clinical Reye's syndrome. Causes of Reye-like syndromes/encephalo-hepatopathies included fulminant hepatitis, Japanese B encephalitis, dengue, septicaemia, and complex febrile fits. It was not possible to differentiate clinical Reye's syndrome from the other encephalo-hepatopathies by either the clinical features (except for jaundice) or biochemical parameters. Liver biopsy is necessary for a definitive diagnosis of Reye's syndrome in Malaysia, because of the high prevalence of Reye-like diseases. The mortality rate in the 2 groups of patients is similar. Ingestion of salicylates was not found to be significantly associated with Reye and Reye-like syndromes in this study.

Glutaric aciduria type II: autopsy study of a case with electron-transferring flavoprotein dehydrogenase deficiency

An autopsy study of glutaric aciduria type II in a 62-day-old Japanese boy is presented. The diagnosis was made by analysis of organic acids in the urine. Immunoblot analysis of liver homogenate confirmed the diagnosis, revealing absence of electron-transferring flavoprotein dehydrogenase. The major findings were fatty changes of variable degree in many organs and tissues, the most severe being found in cardiac myocytes, hepatocytes, renal tubular epithelium, and skeletal muscle fibers. Other pertinent findings included multicystic and dysplastic kidney, pulmonary alveolar proteinosis, and spongiosis and gliosis of the spinal cord. The thymus was markedly depleted, and lymphocytes in the lymph nodes were mainly B cells. Although some of these changes may have been secondary to the sepsis and immunosuppression complicating 2 months of intensive care, the abnormal organic acid metabolism with severe acidosis may have been a significant contributing factor.

Demonstration of zoster virus antibodies in cerebrospinal fluid cells

A method is presented that allows the immunocytochemical detection of varicella zoster virus antigen-binding cerebrospinal fluid cells in zoster ganglionitis. Antigen-binding cells were found only in patients suffering from this disease. The technique is sensitive, specific, inexpensive and relatively fast, and is potentially applicable to other inflammatory central nervous system diseases with immunoglobulin-containing cells (ICC) in CSF. The detection of antigen-binding CSF cells may represent a very early diagnostic test comparable with the early IgM antibodies of the systemic immune response.

Adult Reye's syndrome

A 40-year-old woman with a history of alcohol abuse, drug-related suicide attempts, and depression presented with a flu-like illness, vomiting, and changes in mentation. On admission, therapeutic blood levels of salicylates, trazadone, and acetaminophen were found. A tentative diagnosis of a psychotic crisis with possible superimposed drug overdose was made. The etiology of the patient's acute encephalopathy remained unclear until a plasma ammonia and liver biopsy established the diagnosis of Reye's syndrome. The patient was given supportive therapy and recovered completely.

Clinical manifestations and consequences of influenza

The spread of influenza virus through a community typically causes large increases in medical visits for febrile respiratory disease. Increased school absenteeism occurs early in the epidemic, and school children appear to be important for disseminating the virus. Industrial absenteeism, hospitalizations of adults and infants for pneumonia, and deaths due to pneumonia-influenza all tend to peak later in the epidemic. Although influenza infection rates are highest in persons of school age, hospitalizations and deaths occur primarily in infants and in the elderly, particularly among those with pulmonary, cardiovascular, or other debilitating disorders. Influenza viruses can be spread by aerosol or contact. The primary target cells are those of the respiratory epithelium. In healthy adults, the typical influenza syndrome includes fever, cough, and general aches for three to seven days, but lassitude, cough, and evidence of small-airways disease may persist for weeks. Laryngotracheobronchitis, pneumonia, and unexplained fever are prominent manifestations of influenza that lead to hospitalization of young children. Adults are more likely to have complications of bacterial pneumonia and worsening of chronic pulmonary disease or congestive heart failure. Less frequent complications include myositis, various neurologic disorders, and Reye's syndrome. These consequences of influenza clearly justify strenuous efforts at prevention and control.

Influenza virus-induced encephalopathy in mice: interferon production and natural killer cell activity during acute infection

Mice injected intracerebrally with infectious influenza virus (60 hemagglutinin units) developed lethargy, seizures, comas, and died 2 to 5 days postinfection. As early as 6 h after infection, the cerebrospinal fluid (CSF) in these animals was infiltrated with polymorphonuclear cells, mononuclear leukocytes, and large granular lymphocytes. Potent natural killer (NK) cell activity was observed for both CSF and spleen cell populations over the same period. This NK cell activity correlated with interferon (IFN) levels in the CSF and serum. Treatment of lethally infected mice with either anti-IFN alpha-IFN beta or anti-ganglio-n-tetraoglyceramide antiserum ameliorated the disease, reduced mortality, and effected changes in the relative proportions of inflammatory cell populations infiltrating the CSF. The possible significance of IFN and NK cell activity in the development of this influenza virus-induced encephalopathy is discussed.

Reye's syndrome in Denmark. A retrospective study

We tried to determine the incidence of Reye's syndrome (RS) in Denmark in a retrospective study. As RS is often preceded by influenza B, we chose the year 1979, where an epidemic of influenza B was registered in Denmark. All children aged 1 month to 18 years, who died, were identified, excluding children who died from accidents or malignant diseases. Two hundred and forty-two children died in hospital. Review of the records revealed one case of RS. One hundred and five died outside hospital. Reviewing death certificates and autopsy reports, none of these fulfilled the criteria for RS. All paediatric departments were asked if they had made a diagnosis of RS. None had. In 1979 approximately 1.1 mill. children aged 1 month to 14 years lived in Denmark. This gives an incidence of 0.09 per 100 000 for 1979. Although this is a minimum figure, the incidence of RS in Denmark, for unknown reasons, seems very low.

Differentiation of strains of varicella-zoster virus by changes in neutral lipid metabolism in infected cells

Eleven isolates of varicella-zoster virus were tested for their effects on the incorporation of [14C]acetate into lipids in infected human embryonic lung cells. By relative percent, all virus isolates demonstrated a shift from polar lipid synthesis to neutral lipid, especially triglyceride, synthesis. By data expressed as counts per minute per microgram of protein, the VZV strains could be separated into two groups: those strains which depressed lipid synthesis and those strains which did not depress, and may even have stimulated, lipid, especially triglyceride, synthesis. These results may be useful in understanding the development of lipid changes seen in children affected with Reye's syndrome following chickenpox.

[Encephalitis and hepatitis after varicella. Relations with Reye's syndrome]

We report the case of a 32 year old man who present two weeks after a typical varicella an alteration of consciousness with pleocytosis in the cerebrospinal fluid and abnormalities of EEG and CT Scan. An hepatic dysfunction with cytolysis and a high level of transaminases and ammonia was noted. About this case the author precise the encephalitic complication of varicella, and the different liver abnormalities, such as Reye's syndrome, hepatitis with parcellar necrosis, or hepatitis with hyperammonemia but without cytolysis or necrosis, as in our own.

Influenza B virus model of Reye's syndrome in mice: the effect of aspirin

Aspirin is a possible cofactor with influenza B virus in Reye's syndrome. In an attempt to determine whether single or multiple doses of acetylsalicylic acid (ASA) alter mortality in an influenza B virus mouse model of Reye's syndrome, either ASA (300 to 667 mg/kg) or saline was given intraperitoneally to 3-week-old Balb/c mice. Two hours later, one median lethal dose (LD50) of influenza B/Lee virus was given intravenously. Mortality was not significantly increased by the single ASA dose. Blood ASA levels rose as high as 68 mg/dl. The average ASA blood levels in mice 12 hours after receiving the virus plus 667 mg/kg ASA was 22.6 mg/dl, which was significantly higher than the 3.4 mg/dl for mice who received saline plus ASA. No significant increase in mortality occurred in mice given 67 mg/kg ASA twice daily for 7 days and one LD50 dose of virus on day 4. We conclude that a single dose of ASA at up to half the median lethal dose or multiple doses of ASA do not significantly increase mortality in this influenza virus model of Reye's syndrome. However, influenza B virus infection appears to interfere with ASA metabolism.

Reye syndrome

Reye syndrome has emerged as the quintessential example of an acute metabolic encephalopathy with an annual incidence ranging from 0.3 to 6.0 cases per 100,000 children. The general management has become standardized, and the mortality has declined to approximately 10 per cent. The role of aspirin in the etiopathogenesis remains controversial.

Aflatoxin and Reye's syndrome: a study of livers from deceased cases

In order to reinvestigate a strong reported association, we attempted to identify aflatoxin in the livers of 12 children who presumably died of Reye's Syndrome and in the liver of one child who died accidentally. Aflatoxins were detected, but not confirmed in only one of the liver specimens (limits of detection 20 ppt). In addition, the microscopic appearance of the livers was reviewed. Although most of the cases fit the clinical definition of Reye's Syndrome, the microscopic appearance of the liver was varied. We conclude that aflatoxin is not regularly recoverable from cases of Reye's Syndrome at a high rate, and question the proposed etiologic relationship. We confirm the varied appearance of the liver late in the course of Reye's Syndrome; however, microvesicular fat was present in most cases.

Effects of influenza infection, aspirin, and an arginine-deficient diet on the inner ear in Reye's syndrome

The individual effects of an influenza B viral infection, aspirin, and an arginine-deficient diet on the inner ear were assessed in the ferret model for Reye's syndrome using both functional and morphological parameters. Auditory brainstem evoked responses recorded from inoculated ferrets revealed threshold elevations and increased latencies during the first 72 hours, but approximated those of control animals by 96 hours. Although there was a mild distention of Reissner's membrane, no pronounced structural alterations in sensory or supporting cells were observed in cochleas from inoculated ferrets. The administration of aspirin appeared to alter neither the functional nor the structural integrity of the cochlea. The presentation of an arginine-deficient diet, creating a hyperammonemic condition, led to both altered auditory evoked responses and vacuolization of cochlear tissues after treated animals had undergone seizures and coma. These data demonstrated that both influenza B and the arginine-deficient diet individually affected the hearing of treated animals. The individual agents did not alter the cochlea as severely as when they were presented in combination. These results suggest that hearing impairment in patients with Reye's syndrome may be a result of potentiation of certain metabolic-altering agents.

Altered auditory brainstem evoked responses in the ferret model for Reye's syndrome

The effects of influenza B, aspirin and hyperammonemia on the functional integrity of the cochlea were examined using the ferret model for Reye's syndrome. Auditory brainstem evoked responses (ABR) were recorded from treated ferrets and compared to those recorded from controls. Delayed latencies of all waves, as well as increased I-IV Interwave latencies were observed in recordings from treated ferrets. Importantly, the latencies of Wave I, nerve generator potential from the eighth nerve, and Wave IV, response potential from the brainstem nuclei, increased on Days 3 and 5 of the study. However, recorded ABR from treated ferrets on Day 10 showed that while the latencies of Wave IV were approximate to those of controls, Wave I remained delayed. These results suggest that systemic effects of influenza B, aspirin and hyperammonemia may lead acutely to both peripheral and central auditory dysfunction, and that the functional integrity of the central auditory system may recover more quickly than that of the peripheral system. Furthermore, these results suggest that such effects may lead to acute transient hearing impairment in patients with Reye's syndrome.

The viral mechanism of Reye's syndrome

In the initial stages of Reye's Syndrome, following an influenza infection, the viral RNA polymerase activates liver host cell ornithine decarboxylase by combining with this enzyme. Once the reaction has occurred, ornithine decarboxylase is no longer available to combine with and to activate host cell RNA polymerase. The virally activated ornithine decarboxylase removes ornithine from participation in the urea cycle by metabolizing ornithine to putrescine which, in turn, is metabolized to spermidine. Once ornithine has been removed from participation in the urea cycle, mitochondrial carbamoyl phosphate levels increase until the carbamoyl phosphate passes from the mitochondria into the cytosol where it is metabolized by the de novo pyrimidine synthesis pathway. Through the implementation of this process, the virus has insured that: host cell RNA polymerase in liver cells is inactivated, viral RNA polymerase has complete access to newly synthesized pyrimidines, production of pyrimidines for the synthesis of viral messenger RNA is initiated, spermidine, a mRNA stabilizer is produced, many of the components necessary for viral mRNA synthesis are provided by the host cell's RNA synthesizing mechanism.