SERIOUS MORBIDITY DUE TO ACUTE RESPIRATORY DISEASE ASSOCIATED WITH EPIDEMIC INFLUENZA

Current measures of the health impact of epidemic influenza are focused on analyses of death certificate data which may underestimate the true health effect. Previous investigations of influenza-related morbidity have either lacked virologic confirmation of influenza activity in the community or were not population-based. Community virologic surveillance in Houston has demonstrated that influenza viruses have produced epidemics each year since 1974. This study examined the relation of hospitalized for Acute Respiratory Disease (ARD) to the occurrence of influenza epidemics. Considering only Harris County residents, a total of 13,297 ARD hospital discharge records from hospitals representing 48.4% of Harris County hospital beds were compiled for the period July 1978 through June 1981. Variables collected from each discharge included: age, sex, race, dates of admission and discharge, length of stay, discharge disposition and a maximum of five diagnoses. This three year period included epidemics caused by Influenza A/Brazil (H1N1), Influenza B/Singapore, Influenza A/England (H1N1) and Influenza A/Bangkok (H3N2).^ Correlations of both ARD and pneumonia or influenza hospitalizations with indices of community morbidity (specifically, the weekly frequency of virologically-confirmed influenza virus infections) are consistently strong and suggest that hospitalization data reflect the pattern of influenza activity derived from virologic surveillance.^ While 65 percent of the epidemic period hospital deaths occurred in patients who were 65 years of age or older, fewer than 25 percent of epidemic period ARD hospitalizations occurred in persons of that age group. Over 97 percent of epidemic period hospital deaths were accompanied by a chronic underlying illness, however, 45 percent of ARD hospitalizations during epidemics had no mention of underlying illness. Over 2500 persons, approximately 35 percent of all persons hospitalized during the three epidemics, would have been excluded in an analysis for high risk candidates for influenza prophylaxis.^ These results suggest that examination of hospitalizations for ARD may better define the population-at-risk for serious morbidity associated with epidemic influenza. ^

The active oligomeric state of the minimalistic influenza virus M2 ion channel is a tetramer

The influenza A virus M2 integral membrane protein is an ion channel that permits protons to enter virus particles during uncoating of virions in endosomes and also modulates the pH of the trans-Golgi network in virus-infected cells. The M2 protein is a homo-oligomer of 97 residues, and analysis by chemical cross-linking and SDS/PAGE indicates M2 forms a tetramer. However, a higher order molecular form is sometimes observed and, thus, it is necessary to determine the active form of the molecule. This was done by studying the currents of oocytes that expressed mixtures of the wild-type M2 protein (epitope tagged) and the mutant protein M2-V27S, which is resistant to the inhibitor amantadine. The composition of mixed oligomers of the two proteins expressed at the plasma membrane of individual oocytes was quantified after antibody capture of the cell surface expressed molecules and it was found that the subunits mixed freely. When the ratio of wild-type to mutant protein subunits was 0.85:0.15, the amantadine sensitivity was reduced to 50% and for a ratio of 0.71:0.29 to 20%. These results are consistent with the amantadine-resistant mutant being dominant and the oligomeric state being a tetramer.

Characteristics of virus-specific CD8+ T cells in the liver during the control and resolution phases of influenza pneumonia

Dissection of the primary and secondary response to an influenza A virus established that the liver contains a substantial population of CD8+ T cells specific for the immunodominant epitope formed by H-2Db and the influenza virus nucleoprotein peptide fragment NP366–374 (DbNP366). The numbers of CD8+ DbNP366+ cells in the liver reflected the magnitude of the inflammatory process in the pneumonic lung, though replication of this influenza virus is limited to the respiratory tract. Analysis of surface phenotypes indicated that the liver CD8+ DbNP366+ cells tended to be more “activated” than the set recovered from lymphoid tissue but generally less so than those from the lung. The distinguishing characteristic of the lymphocytes from the liver was that the prevalence of the CD8+ DbNP366+ set was always much higher than the percentage of CD8+ T cells that could be induced to synthesize interferon γ after short-term, in vitro stimulation with the NP366–374 peptide, whereas these values were generally comparable for virus-specific CD8+ T cells recovered from other tissue sites. Also, the numbers of apoptotic CD8+ T cells were higher in the liver. The results overall are consistent with the idea that antigen-specific CD8+ T cells are destroyed in the liver during the control and resolution phases of this viral infection, though this destruction is not necessarily an immediate process.

New approach for inhibiting Rev function and HIV-1 production using the influenza virus NS1 protein.

The Rev protein of HIV-1, which facilitates the nuclear export of HIV-1 pre-mRNAs, has been a target for antiviral therapy. Here we describe a new strategy for inhibiting Rev function and HIV-1 replication. In contrast to previous approaches, we use a wild-type rather than a mutant Rev protein and covalently link this Rev sequence to the NS1 protein of influenza A virus, a protein that inhibits the nuclear export of mRNAs. The NS1 protein contains an RNA-binding domain mutation (RM), so that the only functional RNA-binding domain in the chimeric protein (NS1RM-Rev) is in the Rev protein sequence. In the presence of the NS1RM-Rev chimeric protein, HIV-1 pre-mRNAs were retained in, rather than exported from, the nucleus. In addition, this chimeric protein effectively inhibited Rev function in trans in transfection experiments and effectively inhibited the production of HIV-1 in tissue culture cells transfected with an infectious molecular clone of HIV-1 DNA. The inhibitory activities of the NS1RM-Rev chimera were at least equivalent to those of the Rev M10 mutant protein, which has been considered to be the prototype trans inhibitor of Rev function and is currently in phase I clinical trials for the treatment of AIDS patients. We discuss (i) the potential for increasing the inhibitory activity of NS1-Rev chimeras against HIV-1 and (ii) the need for additional studies to evaluate these chimeras for the treatment of AIDS.

Influenza H1N1: aspectos clínicos e epidemiológicos

Vídeo que apresenta o histórico e a situação mundial, em 2010, da influenza A, subtipo H1N1, mais conhecida como gripe A. Informa sobre as fases de contenção, pandemia e mitigação, aspectos gerais, mutações do vírus, modos de transmissão, período de incubação a transmissibilidade e a sazonalidade, aspectos clínicos, grupos de risco, espectro clínico, complicações, exames de sangue, exames de imagem para os casos mais complicados, apresentação de casos graves e imagens para análise do comprometimento do pulmão, as condutas em casos mais simples e em casos mais graves com síndrome respiratória aguda grave, notificação a vigilância municipal. Lista os sinais de alerta a serem observados em pacientes com o vírus ou com suspeita e as medidas de prevenção e controle.

Who should wear mask against airborne infections? Altering the contact network for controlling the spread of contagious diseases

There are several ways of controlling the propagation of a contagious disease. For instance, to reduce the spreading of an airborne infection, individuals can be encouraged to remain in their homes and/or to wear face masks outside their domiciles. However, when a limited amount of masks is available, who should use them: the susceptible subjects, the infective persons or both populations? Here we employ susceptible-infective-recovered (SIR) models described in terms of ordinary differential equations and probabilistic cellular automata in order to investigate how the deletion of links in the random complex network representing the social contacts among individuals affects the dynamics of a contagious disease. The inspiration for this study comes from recent discussions about the impact of measures usually recommended by health public organizations for preventing the propagation of the swine influenza A (H1N1) virus. Our answer to this question can be valid for other eco-epidemiological systems. (C) 2010 Elsevier BM. All rights reserved.

Clinical patterns and seasonal trends in respiratory syncytial virus hospitalizations in São Paulo, Brazil

The respiratory viruses are recognized as the most frequent lower respiratory tract pathogens for infants and young children in developed countries but less is known for developing populations. The authors conducted a prospective study to evaluate the occurrence, clinical patterns, and seasonal trends of viral infections among hospitalized children with lower respiratory tract disease (Group A). The presence of respiratory viruses in children's nasopharyngeal was assessed at admission in a pediatric ward. Cell cultures and immunofluorescence assays were used for viral identification. Complementary tests included blood and pleural cultures conducted for bacterial investigation. Clinical data and radiological exams were recorded at admission and throughout the hospitalization period. To better evaluate the results, a non- respiratory group of patients (Group B) was also constituted for comparison. Starting in February 1995, during a period of 18 months, 414 children were included- 239 in Group A and 175 in Group B. In Group A, 111 children (46.4%) had 114 viruses detected while only 5 children (2.9%) presented viruses in Group B. Respiratory Syncytial Virus was detected in 100 children from Group A (41.8%), Adenovirus in 11 (4.6%), Influenza A virus in 2 (0.8%), and Parainfluenza virus in one child (0.4%). In Group A, aerobic bacteria were found in 14 cases (5.8%). Respiratory Syncytial Virus was associated to other viruses and/or bacteria in six cases. There were two seasonal trends for Respiratory Syncytial Virus cases, which peaked in May and June. All children affected by the virus were younger than 3 years of age, mostly less than one year old. Episodic diffuse bronchial commitment and/or focal alveolar condensation were the clinical patterns more often associated to Respiratory Syncytial Virus cases. All children from Group A survived. In conclusion, it was observed that Respiratory Syncytial Virus was the most frequent pathogen found in hospitalized children admitted for severe respiratory diseases. Affected children were predominantly infants and boys presenting bronchiolitis and focal pneumonias. Similarly to what occurs in other subtropical regions, the virus outbreaks peak in the fall and their occurrence extends to the winter, which parallels an increase in hospital admissions due to respiratory diseases.

Genomic Signatures and Antiviral Drug Susceptibility Profile of A(H1N1)pdm09

Background: Genetic changes in influenza surface and internal genes can alter viral fitness and virulence. Mutation trend analysis and antiviral drug susceptibility profiling of A(H1N1)pdm09 viruses is essential for risk assessment of emergent strains and disease management. Objective: To profile genomic signatures and antiviral drug resistance of A(H1N1)pdm09 viruses and to discuss the potential role of mutated residues in human host adaptation and virulence. Study design: A(H1N1)pdm09 viruses circulating in Portugal during pandemic and post-pandemic periods and 2009/2010 season. Viruses were isolated in MDCK-SIAT1 cell culture and subjected to mutation analysis of surface and internal proteins, and to antiviral drug susceptibility profiling. Results: The A(H1N1)pdm09 strains circulating during the epidemic period in Portugal were resistant to amantadine. The majority of the strains were found to be susceptible to oseltamivir and zanamivir, with five outliers to neuraminidase inhibitors (NAIs) identified. Specific mutation patterns were detected within the functional domains of internal proteins PB2, PB1, PA, NP, NS1, M1 and NS2/NEP, which were common to all isolates and also some cluster-specific. Discussion: Modification of viral genome transcription, replication and apoptosis kinetics, changes in antigenicity and antiviral drug susceptibility are known determinants of virulence. We report several point mutations with putative roles in viral fitness and virulence, and discuss their potential to result in more virulent phenotypes. Monitoring of specific mutations and genetic patterns in influenza viral genes is essential for risk assessing emergent strains, disease epidemiology and public health implications.

In vivo activation of melanoma-specific CD8(+) T cells by endogenous tumor antigen and peptide vaccines. A comparison to virus-specific T cells.

Many new types of vaccines against infectious or malignant diseases are currently being proposed. Careful characterization of the induced immune response is required in assessing their efficiency. While in most studies human tumor antigen-specific T cells are analyzed after in vitro re-stimulation, we investigated these T cells directly ex vivo using fluorescent tetramers. In peripheral blood lymphocytes from untreated melanoma patients with advanced disease, a fraction of tumor antigen (Melan-A/MART-1)-specific T cells were non-naive, thus revealing tumor-driven immune activation. After immunotherapy with synthetic peptides plus adjuvant, we detected tumor antigen-specific T cells that proliferated and differentiated to memory cells in vivo in some melanoma patients. However, these cells did not present the features of effector cells as found in cytomegalovirus specific T cells analyzed in parallel. Thus, peptide plus adjuvant vaccines can lead to activation and expansion of antigen specific CD8(+) T cells in PBL. Differentiation to protective CD8(+) effector cells may, however, require additional vaccine components that stimulate T cells more efficiently, a major challenge for the development of future immunotherapy.

Trust in medical organizations predicts pandemic (H1N1) 2009 vaccination behavior and perceived efficacy of protection measures in the Swiss public

Following the recent avian influenza and pandemic (H1N1) 2009 outbreaks, public trust in medical and political authorities is emerging as a new predictor of compliance with officially recommended protection measures. In a two-wave longitudinal survey of adults in French-speaking Switzerland, trust in medical organizations longitudinally predicted actual vaccination status 6 months later, during the pandemic (H1N1) 2009 vaccination campaign. No other variables explained significant amounts of variance. Trust in medical organizations also predicted perceived efficacy of officially recommended protection measures (getting vaccinated, washing hands, wearing a mask, sneezing into the elbow), as did beliefs about health issues (perceived vulnerability to disease, threat perceptions). These findings show that in the case of emerging infectious diseases, actual behavior and perceived efficacy of protection measures may have different antecedents. Moreover, they suggest that public trust is a crucial determinant of vaccination behavior and underscore the practical importance of managing trust in disease prevention campaigns.

Sterblichkeit während Grippeepidemien in der Schweiz 1969-1985. [Mortality in influenza epidemics in Switzerland 1969-1985].

In Switzerland from 1969-1985, 9 out of 11 influenza epidemics were associated with a statistically significant increase in mortality. A total of 12,202 excess deaths from all causes was identified. Expected deaths were forecast for each epidemic period separately for 4 age groups using Fourier and Arima modeling. 75.7% of all-cause excess deaths occurred in age group 70 to 89 and 5.1% in age group 1-59. In the 70-89 years old group the excess mortality risk during influenza epidemics was 271.6 per 100,000, whereas in age group 1-59 it was only 1.7 per 100,000. Only 40% of all excess deaths had been ascribed to acute respiratory conditions. Influenza viruses A H3N2 were the most frequently identified agents. In some instances mortality increased before the morbidity reports of the Swiss practitioners indicated the occurrence of an epidemic. Also, morbidity reporting decreased over successive years. A decrease in mortality following the epidemics was not observed. A more complete vaccination of high risk patients in Switzerland is desirable.

Histopathological and immunohistochemical findings of swine with spontaneous influenza A infection in Brazil, 2009-2010

Swine influenza (SI) is caused by the type A swine influenza virus (SIV). It is a highly contagious disease with a rapid course and recovery. The major clinical signs and symptoms are cough, fever, anorexia and poor performance. The disease has been associated with other co-infections in many countries, but not in Brazil, where, however, the first outbreak has been reported in 2011. The main aim of this study was to characterize the histological features in association with the immunohistochemical (IHC) results for influenza A (IA), porcine circovirus type 2 (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV) in lung samples from 60 pigs submitted to Setor de Patologia Veterinária at the Universidade Federal do Rio Grande do Sul (SPV-UFRGS), Brazil, during 2009-2010. All of these lung samples had changes characterized by interstitial pneumonia with necrotizing bronchiolitis, never observed previously in the evaluation of swine lungs in our laboratory routine. Pigs in this study had showed clinical signs of a respiratory infection. Swine samples originated from Rio Grande do Sul 31 (52%), Santa Catarina 14 (23%), Paraná 11 (18%), and Mato Grosso do Sul 4 (7%). Positive anti-IA IHC labelling was observed in 45% of the cases, which were associated with necrotizing bronchiolitis, atelectasis, purulent bronchopneumonia and hyperemia. Moreover, type II pneumocyte hyperplasia, alveolar and bronchiolar polyp-like structures, bronchus-associated lymphoid tissue (BALT) hyperplasia and pleuritis were the significant features in negative anti-IA IHC, which were also associated with chronic lesions. There were only two cases with positive anti-PCV2 IHC and none to PRRSV. Therefore, SIV was the predominant infectious agent in the lung samples studied. The viral antigen is often absent due to the rapid progress of SI, which may explain the negative IHC results for IA (55%); therefore, IHC should be performed at the beginning of the disease. This study has shown how important a careful histological evaluation is for the diagnosis. Since 2009, a new histological feature of swine pneumonia in animals with respiratory clinical signs has been observed in samples from pigs with clinical respiratory disease submitted to SPV-UFRGS. In addition, the results proved the importance of histological evaluation for swine herd health management.

Emerging animal viruses: real threats or simple bystanders?

The list of animal viruses has been frequently added of new members raising permanent concerns to virologists and veterinarians. The pathogenic potential and association with disease have been clearly demonstrated for some, but not for all of these emerging viruses. This review describes recent discoveries of animal viruses and their potential relevance for veterinary practice. Dogs were considered refractory to influenza viruses until 2004, when an influenza A virus subtype H3N8 was transmitted from horses and produced severe respiratory disease in racing greyhounds in Florida/USA. The novel virus, named canine influenza virus (CIV), is considered now a separate virus lineage and has spread among urban canine population in the USA. A new pestivirus (Flaviviridae), tentatively called HoBi-like pestivirus, was identified in 2004 in commercial fetal bovine serum from Brazil. Hobi-like viruses are genetically and antigenically related to bovine viral diarrhea virus (BVDV) and induce similar clinical manifestations. These novel viruses seem to be widespread in Brazilian herds and have also been detected in Southeast Asia and Europe. In 2011, a novel mosquito-borne orthobunyavirus, named Schmallenberg virus (SBV), was associated with fever, drop in milk production, abortion and newborn malformation in cattle and sheep in Germany. Subsequently, the virus disseminated over several European countries and currently represents a real treat for animal health. The origin of SBV is still a matter of debate but it may be a reassortant from previous known bunyaviruses Shamonda and Satuperi. Hepatitis E virus (HEV, family Hepeviridae) is a long known agent of human acute hepatitis and in 1997 was first identified in pigs. Current data indicates that swine HEV is spread worldwide, mainly associated with subclinical infection. Two of the four HEV genotypes are zoonotic and may be transmitted between swine and human by contaminated water and undercooked pork meat. The current distribution and impact of HEV infection in swine production are largely unknown. Avian gyrovirus type 2 (AGV2) is a newly described Gyrovirus, family Circoviridae, which was unexpectedly found in sera of poultry suspected to be infected with chicken anemia virus (CAV). AGV2 is closely related to CAV but displays sufficient genomic differences to be classified as a distinct species. AGV2 seems to be distributed in Brazil and also in other countries but its pathogenic role for chickens is still under investigation. Finally, the long time and intensive search for animal relatives of human hepatitis C virus (HCV) has led to the identification of novel hepaciviruses in dogs (canine hepacivirus [CHV]), horses (non-primate hepaciviruses [NPHV] or Theiler's disease associated virus [TDAV]) and rodents. For these, a clear and definitive association with disease is still lacking and only time and investigation will tell whether they are real disease agents or simple spectators.

Isolation and Characterization of Ovomucin - a Bioactive Agent of Egg White

The hen’s egg is a source of new life. Therefore, it contains many biologically active compounds. In addition to being a very nutritious food and also commonly used in the food industry due to its many techno-functional properties, the egg can serve as a source of compounds used as nutra-, pharmaand cosmeceuticals. One such interesting compound is ovomucin, an egg white protein responsible for the gel-like properties of thick egg white. Previous studies have indicated that ovomucin and ovomucin-derived peptides have several different bioactive properties. The objectives of the present study were to develop isolation methods for ovomucin, to characterize the structure of ovomucin, to compare various egg fractions as sources of ovomucin, to study the effects of various dissolving methods for ovomucin, and to investigate the bioactive properties of ovomucin and ovomucin-derived peptides. A simple and rapid method for crude ovomucin separation was developed. By using this method crude ovomucin was isolated within hours, compared to the 1-2 days (including a dialysis step) needed when using several other methods. Structural characterization revealed that ovomucin is composed of two subunits, α- and β-ovomucin, as egg white protein formerly called α1-ovomucin seemed to be ovostatin. However, it might be possible that ovostatin is associated within β- and α-ovomucin. This interaction could even have some effect on the physical nature of various egg white layers. Although filtration by-product fraction was a very prominent source of both crude and β-ovomucin, process development has reduced its amount so significantly that it has no practical meaning anymore. Thus, the commercial liquid egg white is probably the best option, especially if it generally contains amounts of β-ovomucin as high as were found in these studies. Crude ovomucin was dissolved both by using physical and enzymic methods. Although sonication was the most effective physical method for ovomucin solubilisation, colloid milling seemed to be a very promising alternative. A milk-like, smooth and opaque crude ovomucin suspension was attained by using a colloid mill. The dissolved ovomucin fractions were further tested for bioactive properties, and it was found that three dissolving methods tested produced moderate antiviral activity against Newcastle disease virus, namely colloid milling, enzymatic hydrolysis and a combination of sonicaton and enzymatic hydrolysis. Moreover, trypsin-digested crude ovomucin was found to have moderate antiviral activity against avian influenza virus: both subtype H5 and H7.

Connections: can the 20th century coronary heart disease epidemic reveal something about the 1918 influenza lethality?

This essay proposes that the ecologic association shown between the 20th century coronary heart disease epidemic and the 1918 influenza pandemic could shed light on the mechanism associated with the high lethality of the latter. It suggests that an autoimmune interference at the apoB-LDL interface could explain both hypercholesterolemia and inflammation (through interference with the cellular metabolism of arachidonic acid). Autoimmune inflammation, then, would explain the 1950s-60s acute coronary events (coronary thrombosis upon influenza re-infection) and the respiratory failure seen among young adults in 1918. This hypothesis also argues that the lethality of the 1918 pandemic may have not depended so much on the 1918 virus as on an immune vulnerability to it, possibly resulting from an earlier priming of cohorts born around 1890 by the 1890 influenza pandemic virus.