Search

The constantly changing pattern in the dominance of viral strains and their evolving subclades during the seasons substantially influences influenza vaccine effectiveness (IVE). In order to further substantiate the importance of detailed data of genetic virus characterization for IVE estimates during the seasons, we performed influenza virus type and subtype specific IVE estimates. IVE estimates were assessed using a test-negative case-control design, in the context of the intraseasonal changes of the heterogeneous mix of circulating influenza virus strains for three influenza seasons (2016/17 to 2018/19) in Austria. Adjusted overall IVE over the three seasons 2016/17, 2017/18, and 2018/19 were −26, 39, and 63%, respectively. In accordance with the changing pattern of the circulating strains a broad range of overall and subtype specific IVEs was obtained: A(H3N2) specific IVE ranged between −26% for season 2016/17 to 58% in season 2018/19, A(H1N1)pdm09 specific IVE was 25% for the season 2017/18 and 65% for the season 2018/19 and Influenza B specific IVE for season 2017/18 was 45%. The results obtained in our study over the three seasons demonstrate the increasingly complex dynamic of the ever changing genetic pattern of the circulating influenza viruses and their influence on IVE estimates. This emphasizes the importance of detailed genetic virus surveillance for reliable IVE estimates.

During the influenza pandemic 2009 children and adults differed in the clinical course of the influenza disease. In following the question arose, if the case definitions used within the national and international organizations are an adequate tool for the clinical diagnosis of influenza in children as well as in adults. Therefore medical charts from 146 children and 229 adults were retrospectively analyzed. In addition, the initial viral loads of all 375 patients and the duration of virus shedding of a subset of 79 patients were also investigated. Children show a wider clinical spectrum including gastro enteric symptoms and also a different spectrum of laboratory parameters like elevated CRP-levels, leucocytosis, and higher viral loads. Further, children show significantly more often complications, for example, myositis that may be underdiagnosed. In patients receiving antiviral-therapy complications occurred significantly less often and the presence of symptoms was significantly shorter compared to the untreated group (2.3 days vs. 6.0 days). In summary, the differences in the clinical picture between children and adults should be taken into consideration for the clinical diagnosis of influenza and also for a future discussion on age specific influenza case definitions.

The publisher regrets that the co-authors in the “European region influenza surveillance network” were not tagged correctly. The full and complete list of authors and their affiliations for this article is given above. The publisher would like to apologise for any inconvenience caused.

Respiratory syncytial virus (RSV) is one of the most important pathogen causing severe lower respiratory tract infections in all age groups often requiring hospitalization. Rapid laboratory diagnosis of RSV infection significantly decreases the use of antibiotics, additional laboratory testing and is associated with shorter hospitalization periods. The specific diagnosis of RSV infection is based on the detection of virus or viral antigens or virus specific nucleic acid sequences in respiratory secretions. The kind and quality of the clinical specimen exerts a considerable influence on the results of all currently used viral detection assays. Antigen based tests are widely available, easy to perform and the results are available in a short time but their reduced sensitivity and specificity represent a considerable shortcoming. Among the methods available isolation in cell culture was considered the gold standard for the sensitive identification of RSV but is gradually replaced by highly sensitive and specific nucleic acid amplification assays that provide more rapid results. Of these reverse transcription polymerase chain reaction (PCR) was the first and is still the most frequently used nucleic acid-based assay. New methodologies, as for example the real-time PCR methods allow the quantification of viral nucleic acids in the clinical sample. Disadvantages of the nucleic acid based assays are their high costs and their limited standardization. Future research on new methodologies for the diagnosis of viral respiratory tract infections should focus on the development of sensitive, rapid and cost effective test systems allowing the screening for all probable causative agents. In addition varying testing protocols for summer and winter months based on epidemiologic data are needed to direct their practical use.

BACKGROUND. The nonstructural protein NS1 of influenza virus counteracts the interferon-mediated immune response of the host. By deleting the open reading frame of NS1, we have generated a novel type of influenza vaccine. We studied the safety and immunogenicity of an influenza strain lacking the NS1 gene (DeltaNS1-H1N1) in healthy volunteers. METHODS. Healthy seronegative adult volunteers were randomized to receive either a single intranasal dose of the DeltaNS1-H1N1 A/New Caledonia vaccine at 1 of 5 dose levels (6.4, 6.7, 7.0, 7.4, and 7.7 log(10) median tissue culture infective dose) (n = 36 recipients) or placebo (n = 12 recipients). RESULTS. Intranasal vaccination with the replication-deficient DeltaNS1-H1N1 vaccine was well tolerated. Rhinitis-like symptoms and headache were the most common adverse events identified during the 28-day observation period. Adverse events were similarly distributed between the treatment and placebo groups. Vaccine-specific local and serum antibodies were induced in a dose-dependent manner. In the highest dose group, vaccine-specific antibodies were detected in 10 of 12 volunteers. Importantly, the vaccine also induced neutralizing antibodies against heterologous drift variants. CONCLUSIONS. We show that vaccination with an influenza virus strain lacking the viral interferon antagonist NS1 induces statistically significant levels of strain-specific and cross-neutralizing antibodies despite the highly attenuated replication-deficient phenotype. Further studies are warranted to determine whether these results translate into protection from influenza virus infection. TRIAL REGISTRATION. ClinicalTrials.gov identifier: NCT00724997 .

Human metapneumovirus (HMPV) is considered an important respiratory pathogen in young children. To gain insight into the seasonality and epidemiologic characteristics of HMPV infection, this study determined the frequency of HMPV infections in hospitalized infants during a 7-year period.By use of real-time reverse-transcriptase polymerase chain reaction, nasopharyngeal aspirates from 1612 infants less than 2 years of age who were hospitalized for acute respiratory tract illness were tested for the presence of HMPV. Weekly HMPV testing data were analyzed to assess the timing of HMPV activity. Season variability was estimated by comparing the onset, duration, peak, and end of outbreaks from October 2000 through October 2007.Overall, 109 (6.8%) of 1612 cases of acute respiratory illness were associated with HMPV infection. Seasonal HMPV activity varied substantially from year to year, both in prevalence rates of HMPV cases and in seasonal timing of outbreaks. HMPV activity was characterized by a biennial rhythm, with spring seasons occurring every second year, and these accounted for a substantial proportion, up to 30%, of hospitalized cases of acute respiratory tract illness.HMPV activity varies substantially from year to year, both in the frequency and timing of illness and shows a biennial pattern of alternating winter and spring activity.

Background. Cytomegalovirus (CMV) is a major pathogen in lung transplant recipients (LTRs). The emergence of different CMV strains in lung and blood after transplantation has not yet been analyzed. Methods. In total, 75 serum and 91 broncheoalveolar lavage (BAL) samples obtained from 25 LTRs in the follow-up after transplantation were tested for the presence of different CMV strains. The gB, gN, and gO genes of the CMV isolates were analyzed by subtype-specific PCR, restriction fragment length polymorphism (RFLP), sequencing, and phylogenetic analysis. Results. Mixed CMV-strain populations were detected after cessation of antiviral prophylaxis in up to 80% and 90% of the patients' BAL and serum, respectively, and this was independent of the CMV serostatus of donor and recipient. In five patients, the same single CMV strain was consistently detectable over at least 1 year in lung and blood, although in two of these cases donor and recipient had both been CMV-seropositive. Most CMV strains were distributed in the lung and blood compartment. Symptomatic CMV infection within the first year after transplantation was observed only in patients with mixed CMV-strain populations (P

Background: There is an increasing awareness of the need for external quality control of diagnostic virology. Objectives: To assess the quality of nucleic acid amplification tests (NAT) of herpes simplex within Europe. Study design: Herpes simplex virus (HSV) proficiency panels were produced at the Swedish Institute for Infectious Disease Control on behalf of the European Union Concerted Action for Quality Control of Nucleic Acid Amplification in 1999 and 2000. Nine reference laboratories evaluated the production process. Each panel consisted of 12 coded samples with various concentrations of inactivated, freeze-dried HSV type 1 (HSV-1), and HSV type 2 (HSV-2), or negative controls. Positive samples included HSV-1 and HSV-2 in a range of concentrations (2×102 to 2×107 genome copies per ml) similar to those found in cerebrospinal fluids from patients with HSV encephalitis. Results: Sixty-six participants reported a total of 76 data sets for panel 1, and 71 reported 78 data sets for panel 2. The majority of the participants employed qualitative ‘in-house’ polymerase chain reaction (PCR) methods, either in a single, nested or semi-nested format. For panel 2, 9 laboratories reported use of ‘real-time’ PCR in contrast to 3 for panel 1. Three laboratories submitted quantitative results on both panels. Thirty percent of the data sets had correct results for the entire panel 1. In 6 data sets (8%) a total of 11 false positive results were reported. For panel 2, 28% of the data sets had correct result. Nineteen false positive results were reported in 14 data sets (18%), but most of the incorrect results reflected a lack of test sensitivity. Conclusions: The relatively high frequency of false positive results and the large number of false-negative results, albeit at low copy number, stress the need for improvement in the quality of HSV NAT and for external quality control programmes.

Serum samples from 68 immunocompetent infants (mean age, 12.6 months) with an acute adenovirus infection of the respiratory tract (39 experiencing their first adenovirus infection) were tested for the presence of adenovirus DNA, to investigate whether viral dissemination via the blood is usually present in the immunocompetent patient. Using a nested polymerase chain reaction assay, adenovirus DNA could be detected in acute-phase serum samples from 28 (41%) children. Adenovirus DNA was never found in follow-up serum samples, indicating a short period ( approximately 1 week) of viral dissemination. In children experiencing their first adenovirus infection, viral DNA could be detected in 72% of the acute-phase serum samples collected within the first week after onset of symptoms. Adenovirus DNA could also be detected in 25% of the acute-phase serum samples from patients with reinfection.

During the influenza pandemic 2009 children and adults differed in the clinical course of the influenza disease. In following the question arose, if the case definitions used within the national and international organizations are an adequate tool for the clinical diagnosis of influenza in children as well as in adults. Therefore medical charts from 146 children and 229 adults were retrospectively analyzed. In addition, the initial viral loads of all 375 patients and the duration of virus shedding of a subset of 79 patients were also investigated. Children show a wider clinical spectrum including gastro enteric symptoms and also a different spectrum of laboratory parameters like elevated CRP-levels, leucocytosis, and higher viral loads. Further, children show significantly more often complications, for example, myositis that may be underdiagnosed. In patients receiving antiviral-therapy complications occurred significantly less often and the presence of symptoms was significantly shorter compared to the untreated group (2.3 days vs. 6.0 days). In summary, the differences in the clinical picture between children and adults should be taken into consideration for the clinical diagnosis of influenza and also for a future discussion on age specific influenza case definitions.

The objectives of this study were to evaluate the reliability of herpes simplex virus (HSV) PCR testing in cerebrospinal fluid (CSF) for the detection of herpes simplex encephalitis. This was done by examining retrospectively the clinical follow-up of a large group of patients tested routinely by HSV-PCR. In addition, an attempt was made to assess the incidence of herpes simplex encephalitis in a central European population. CSF samples from 1,427 patients from all Vienna hospitals were submitted for HSV-PCR testing during a period of 4 years and 8 months. Herpes simplex encephalitis was detected by PCR in 12 cases and by serological methods in one additional patient. Retrospective analysis of the course of disease, which was possible in 799 PCR-negative patients, led to the identification of three additional cases in which herpes simplex encephalitis appears to have occurred despite negative PCR results. Failure of the PCR in these patients is most likely due to the time of obtaining CSF during the course of disease. A high specificity of the assay was demonstrated by the lack of false positive results in any of the 708 cases in which other causes for the neurological symptoms had been identified in the follow-up. The incidence of herpes simplex encephalitis in the population of Vienna was between 1 case/469,000–577,000 individuals/year. The highest annual incidence was detected in the age group between 3 months and 3 years, which, however, could not be confirmed statistically. J. Med. Virol. 64:531–536, 2001. © 2001 Wiley-Liss, Inc.

BACKGROUND: Human metapneumovirus (HMPV) is a major cause of respiratory tract illness in young children and causes annual outbreaks in winter and spring seasons. We evaluated the subgroups of HMPV that caused annual outbreaks and its seasonal occurrence during a 21-year period. METHODS: Real-time PCR was used for detection of HMPV in 3576 nasopharyngeal aspirates that had been continuously collected year-round for the years 1987 to 2008 from infants hospitalized with acute respiratory tract illness. Phylogenetic analysis was used to assess HMPV subgroups. RESULTS: Of the 3576 samples obtained, 202 (5.6%) tested positive for HMPV. All known HMPV subgroups (A1, A2a, A2b, B1, B2) could be identified as important respiratory tract pathogens in infants. We found that one HMPV subgroup predominated each year, and it was displaced by another subgroup every 1 to 3 years. Besides the frequent change in predominant HMPV subgroups, we observed a yearly shift in the seasonal occurrence, with a strong peak of HMPV activity in late spring-summer months every second year. CONCLUSION: HMPV activity is characterized by a periodic change in the predominant subgroup and it shows a stable seasonal rhythm of alternating winter and spring activity.

A seminested RT-PCR for amplification of Respiratory syncytial virus (RSV)-RNA in nasal aspirates has been developed and used to test nasopharyngeal aspirates (NPAs) from 132 infants hospitalized with acute respiratory tract infections during winter epidemics. The results were compared with those obtained by virus isolation in tissue culture and antigen detection with an enzyme-linked immunosorbent assay (Ag-ELISA). RSV-RNA was detected by seminested RT-PCR in 57 of the 59 samples that were positive by virus isolation and/or ELISA, as well as in 25 of 73 samples negative by virus isolation and ELISA. Eighteen of these 25 samples were obtained from children older than one year of age, 17 of whom were experiencing reinfection, as indicated by the presence of preexisting serum RSV-IgG antibodies. These results indicate that seminested RT-PCR is more sensitive than conventional methods for the detection of RSV in patients experiencing reinfections and suggest that this assay might also be useful for rapid diagnosis of RSV infections in older people. J. Med. Virol. 53:366–371, 1997. © 1997 Wiley-Liss, Inc.

Influenza epidemics lead to an increase in hospitalizations and deaths. Up to now the overall impact of attributable deaths due to seasonal and pandemic influenza viruses in Austria has not been investigated in detail. Therefore we compared the number and age distribution of influenza associated deaths during ten influenza epidemic seasons to those observed during the pandemic influenza A(H1N1)2009 season. A Poisson model, relating age and daily deaths to week of influenza season using national mortality and viral surveillance data adjusted for the confounding effect of co-circulating Respiratory Syncytial Virus was used. We estimated an average of 316 influenza associated deaths per seasonal influenza epidemic (1999/2000–2008/2009) and 264 for the pandemic influenza season 2009/2010 in the area of Vienna, Austria. Comparing the mortality data for seasonal and pandemic influenza viruses in different age groups revealed a statistically significant increase in mortality for pandemic A(H1N1)2009 influenza virus in the age groups below 34 years of age and a significant decrease in mortality in those above 55 years. Our data adjusted for co-circulating RSV confirm the different mortality pattern of seasonal and pandemic influenza A(H1N1)2009 virus in different age groups.

To differentiate active human herpesvirus type 6 (HHV-6) infection from inherited HHV-6 (iHHV-6), we analyzed dried blood spots from archived newborn screening cards in 3 patients with high HHV-6 DNA copy numbers. Two patients were positive for HHV-6 DNA as neonates suggesting iHHV-6. In 1 patient, the absence of HHV-6 DNA excluded iHHV-6.

Contemporary influenza B virus strains were generated encoding C-terminally truncated NS1 proteins. Viable viruses containing the N-terminal 14, 38, 57 or 80 aa of the NS1 protein were rescued in Vero cells. The influenza B virus NS1-truncated mutants were impaired in their ability to counteract interferon (IFN) production, induce antiviral pro-inflammatory cytokines early after infection and show attenuated or restricted growth in IFN-competent hosts. In Vero cells, all of the mutant viruses replicated to high titres comparable to the wild-type influenza B virus. Mice that received a single, intranasal immunization of the NS1-truncated mutants elicited an antibody response and protection against wild-type virus challenge. Therefore, these NS1-truncated mutants should prove useful as potential candidates for live-attenuated influenza virus vaccines.

Human influenza viruses are subject to continuous antigenic drift and this phenomenon poses great problems for the annual production of vaccines which should ideally be manufactured from strains closely matching the predominant strains of the coming influenza season. We have investigated the dynamics of antigenic and genetic changes in the hemagglutinins of circulating influenza A/H3N2 strains in three consecutive seasons (2002/2003 to 2004/2005) in Austria by sequence analysis of the HA1 domain and by antigenic characterization using a hemagglutination inhibition assay. Each of the three seasons was dominated by a single and different H3N2 variant, but in all cases sequencing revealed the co-circulation of a drift variant which would have been missed by conventional antigenic analysis. These emerging strains always showed already a close genetic relationship to the dominating strain of the following season. Our results underscore the value of monitoring seasonal influenza strain dynamics by sequence analysis as an instrument that can provide important and timely information on the appearance of strains with epidemiologic significance.

Dual respiratory viral infections are frequently associated with lower respiratory tract illness in infants. This study aimed to determine the impact of a dual respiratory viral infection on specific aspects of the infant's immune response and the clinical course of illness.A prospective study was performed with 772 infants hospitalized from October 2000 through July 2004. Sensitive polymerase chain reaction methodology revealed the presence of a single respiratory virus in 443 (57%) of 772 cases, whereas dual infections were identified in 153 (20%) of cases. From 250 infants with confirmed respiratory viral infection, fresh heparinized blood was analyzed for interferon-gamma (IFN-gamma) responses by flow cytometry. Of these, 191 patients had a single infection with respiratory syncytial virus (RSV), rhinoviruses, adenoviruses or influenza viruses; and 59 patients had a dual infection with RSV and rhinoviruses, RSV and adenoviruses, influenza viruses and rhinoviruses or adenoviruses and rhinoviruses. The clinical features and peripheral lymphocyte IFN-gamma responses were compared among infants with single or dual infections.It was found that dual infections with non-RSV respiratory viruses induced peripheral blood mononuclear cell IFN-gamma responses that mimic those of single infections, whereas coinfection with RSV was associated with reduced IFN-gamma responses and a more severe clinical course of lower respiratory tract disease.The results indicate that the clinical characteristics and the IFN-gamma response differ significantly in single and dual respiratory viral infection, depending on the nature of the simultaneously detected viruses. In dual infections, RSV involvement was associated with a decreased IFN-gamma response in peripheral blood mononuclear cell and an increase in severity of illness.

We examined the in vivo cell-mediated immune response in infants with respiratory syncytial virus (RSV) infection in order to gain information about the pathogenesis of severe RSV disease in infancy. Semiquantitative reverse transcription-polymerase chain reaction and three-color flow cytometry were used to determine the levels of messenger RNA (mRNA) for interferon (IFN)-gamma in peripheral blood mononuclear cells, and the distribution of lymphocyte subsets in infants with acute RSV infection. The findings were correlated with the severity of the patients' illness and the production of RSV-specific IgE antibodies (RSV-IgE). Significantly lower IFN-gamma levels and T-lymphocyte counts in the acute phase of illness were observed in infants with severe RSV disease than in those with a milder clinical course of illness. The induction of RSV-IgE was not related to IFN-gamma levels in the acute phase of illness, but rather correlated with IFN-gamma expression during convalescence. The data indicate that reduced IFN-gamma expression may be an important factor in the pathogenesis of severe RSV disease in infancy.

We report a case of persistent infection with human parvovirus B19 (PVB19), manifesting clinically as recurrent agranulocytosis and in bone marrow biopsy as recurrent pure granulocytic aplasia. Persistence of parvovirus infection was documented by the presence of PVB19 DNA and anti-PVB19-IgM antibodies in the serum for a period of 19 months. Granulocytic aplasia occurred only when anti-PVB19-IgG antibodies were not detectable in the serum and granulopoiesis showed immediate recovery with high dose intravenous immunoglobulin treatment. This case report suggests that the erythroid precursor cell may not be the only target cell of PVB19 infection. We suggest testing for active parvovirus infection in cases of aplasia of any lineage of the haematopoietic system.

Rhinoviruses were isolated from nasopharyngeal secretions of 49 children hospitalized because of severe respiratory tract infection. The isolates were typed using 90 type-specific antisera. No obvious relation between certain serotypes and the severity of illness was found. Serum samples were drawn from all children simultaneously with the nasopharyngeal secretions and screened for the presence of type-specific neutralizing antibodies. Children aged 1 week t o 6 months had higher neutralizing antibody titers and revealed a lower degree of morbidity than older children. The decline of neutralizing serum antibodies with increasing age was correlated with a higher incidence of severe disease in those aged 7-12 months. Nevertheless, also in this age group children with mild clinical courses of disease were observed despite a low concentration or an absence of neutralizing serum antibodies. This indicates that not only neutralizing serum antibodies, but other factors also influence the clinical expression of RHV-induced disease.

Im allgemeinen treten virale Erkrankungen des zentralen Nervensystems als Komplikationen systemischer Viruserkrankungen auf, in deren Verlauf die Viren die Meningen, das Gehirn bzw. Ruckenmark erreichen. Die klinischen Verdachtsdiagnose virale Meningitis, Meningioenzephalitis bzw. Enzephalomyelitis wird aufgrund der klinischen Befunde (z. B. Nackensteifigkeit, Bewustseinstrubung, Fieber, Exanthem etc.); dem Liquorbefund (in der Regel: klar, Pleozytose von 40–400/3 Zellen mit Uberwiegen der mononuklearen Zellen, normale bis leicht erhohte Protein- und Zuckerwerte); den anamnestischen Erhebungen (z. B.: Insektenstiche, Fernreisen, Impfungen etc.) gestellt.

A commercially available monoclonal antibody against the 72000 Dalton early nuclear protein (EA) of cytomegalovirus (CMV) strain AD169 was used in an indirect immunofluorescence staining procedure (IF) for rapid detection of CMV-infected cells in tissue cultures inoculated with clinical specimens (200 urines, 22 throat washings, 5 stools, 4 bronchoalveolar lavage fluids). The results obtained by this method were compared with those obtained by virus isolation with and without centrifugal enhancement of viral infectivity. In 66 (28.6%) of the 231 samples, CMV was detected by at least one of the methods used. Of 59 specimens producing CMV-specific cytopathic effect (CPE) in tissue culture, 46 (78%) were also positive in the EA test 16 hours after inoculation. Seven CPE-negative samples were, however, positive in the EA test. Five (38%) of the false negative EA test results were due to CMV strains that did not react with the monoclonal antibody used.

A retrospective study on the frequency, site and distribution of rabies and Herpes simplex virus (HSV) type 1 antigens by means of immunofluorescence (IF) and immunoperoxidase (IP) techniques was performed on routinely processed (formol-fixed, paraffin-embedded) brain autopsy material stored for up to 25 years. In 2 animal and 2 human rabies cases, inclusion bodies in neuronal cytoplasm and processes were brilliantly stained for rabies antigens by IF but were much less prominent or absent in usual histological stains. In 33 cases of histopathologically diagnosed necrotizing encephalitis, HSV antigens were demonstrated in 18 of 26 acute cases; 7 subacute cases (course longer than 4 weeks) were all negative for HSV antigens. Neuronal cytoplasm and nuclear membranes were the main sites of HSV antigens; nuclear inclusion bodies were inconstantly stained. Since most of HSV antigen negative cases also showed intranuclear inclusion bodies in HE stains, such nuclear inclusions are no reliable criterion for an HSV aetiology. On the other hand, their absence does not rule out a herpetic aetiology, but such a constellation is rare (only one of 18 HSV positive cases). Distribution of cells showing a positive reaction for HSV antigens may be patchy and irregular; therefore, a false negative result must be expected if very small tissue samples are examined (e.g, in needle biopsies from temporal lobe). In the leptomeninges, HSV antigen positive cells were found inconstantly and only in small numbers; this finding makes unlikely the possibility of an intravital diagnosis of HSV encephalitis by immunostaining of cerebrospinal fluid (CSF) cell preparations. Both immunohistological techniques applied in this study (IF and IP) gave the same results. Imprint preparations are useful when quick diagnosis is necessary. Immunohistological investigations are a simple and effective means to demonstrate a viral aetiology even in routinely processed material; the use of such material rules out hazards in laboratories which are not designed to handle highly infectious fresh material.

A prospective study was carried out to investigate the contribution of rhinoviruses to respiratory viral infections in children and to investigate the influence of age, passive smoking, and educational level of the head of the family on the clinical course of viral respiratory disease. Nasopharyngeal aspirates from 519 infants (90.8% inpatients, 9.2% outpatients) were screened for the presence of rhinoviruses, respiratory syncytial virus (RSV), adenoviruses, parainfluenza virus types 1, 2, 3, influenza virus types A and B, and enteroviruses by tissue culture isolation procedure, enzyme-linked immunosorbent assay, and/or indirect immunofluorescence method. The total detection rate was 42.4%. The rate decreased with increasing age. Higher detection rates were observed in specimens from children suffering from a more severe respiratory disease, and the highest rate of virus-positive specimens was found in those aged 0-6 months. Second to RSV (23.1%), rhinoviruses were the most frequently recovered pathogens found in 11.8% of children with acute respiratory tract infections (RTI). In the age group 0-6 months the majority of severe respiratory illnesses was due to RSV. In infants aged 6 months to 1 year a decrease in the number of severe illnesses caused by RSV and an increase in the number of children suffering from a more severe RTI caused by rhinoviruses was found. With the possible exception of one group of children infected with rhinoviruses, a negative effect of passive smoking on the incidence and severity of viral RTI could not be established. A beneficial effect of breast feeding on the severity of viral RTI could not be definitely demonstrated.

The protein specificities of IgG, IgM, and IgA antibodies induced during respiratory syncytial virus (RSV) infection in 74 patients (4 weeks to 81 years of age) were investigated using the technique of immunoblotting. Although the pattern of antibody reactivity varied among patients, most of the humoral immune response in all age groups was directed against the 48, 42, 35, and 27 K proteins. An infant's own antibody response was discernible in 55 of the 57 children below 1 year of age, despite the presence of maternally derived antibodies. Antibody against the 90 K surface glycoprotein was not detectable in those less than 1 year of age. Primary RSV infection induced antibodies only against a subset of RSV proteins. Although a broadening of the antibody response occurred with increasing age and in the course of reinfection, an immune response to all the viral structural proteins was observed rarely.

In serum and CSF-specimens from 41 patients with recent TBE, antibodies of the IgM and IgG type against TBE and mumps were determined. In all sera IgM- and IgG-anti-bodies against TBE were present, but only 20 CSF samples also contained both antibodies, in 2 only IgM- and in 8 only IgG-antibodies against TBE were detectable. The ratio of CSF to serum antibody was determined. Low ratios indicate a defect in the blood brain barrier or a local antibody production in the brain. Such a low ratio for IgG- or IgM- or for both antibody-classes was detected in 21 patients. Antibodies (only IgG-type) against mumps were found in 39 sera and in 20 CSF specimens of 41 TBE patients. Again the ratio of CSF to serum mumps antibodies were calculated and a low ratio was detected in 6 patients. A high antibody ratio for mumps IgG-antibodies, but a low for TBE antibodies (IgM and IgG) was found in 6 patients. This indicates in those cases a local antibody production in the brain itself.

Immunofluorescence (IF) techniques performed on formol-fixed, paraffin-embedded and protease-pretreated sections from autopsy brain for demonstration of rabies and Herpes simplex type 1 (HSV-1) antigens proved to be a simple and effective method to ensure the etiology of some viral encephalitides. In contrast to fresh material, the use of formol-fixed tissues rules out any risk in handling highly infectious material. Another major advantage is the possibility of comparing IF appearance with normal histology of the same section by post-staining with hematoxilin-eosin (H.E.) or other stains.

Mumps virus specific antibody concentrations were determined by enzyme-linked immunosorbent assay (ELISA), hemolysis-in-gel (HIG) test, and hemagglutination-inhibition (HI) test in 17 adult volunteers before and after vaccination with a new live mumps vaccine, Pariorix. The results of the present study indicate that the strain Urabe-Am 9 of the mumps virus (Pariorix) induces antibodies in 100% of seronegative adults when measured by ELISA and in 70.6% and 64.7% in HIG and HI, respectively. ELISA is therefore a very sensitive and reliable method for the demonstration of sero-conversion after vaccination. The vaccine was well tolerated and clinically acceptable in the group of adult volunteers.

A prospective, randomised clinical trial was conducted to evaluate the efficacy of two live attenuated mumps-measles vaccines, the Urabe Am 9-Schwarz and the Jeryl Lynn-Moraten vaccine, in 400 young children aged 9 months-4.5 years (median 13.4 months). Antibody responses to both vaccine components were measured by the enzyme-linked immunosorbent assay (ELISA); 96.9% of the seronegative children who received the Urabe Am 9-Schwarz vaccine showed satisfactory mumps antibody responses compared to 90% of the Jeryl Lynn-Moraten vaccine recipients (P less than .01). Similar proportions of both groups, 98.5% and 96.8%, respectively, developed measles virus specific antibodies. Both vaccines were equally well tolerated and clinically acceptable.

An ELISA for the detection of mumps virus-specific IgG and IgM antibodies was developed. Three different antigen preparations were compared. Equally good results were obtained with virus concentrated by ultracentrifugation and with virus that was further purified by sucrose gradient centrifugation. Crude infected allantoic fluid was unsuitable for use an antigen. The variability and reproducibility of the tests were satisfactory. When the ELISA was compared to conventional serological methods, a good correlation of IgG absorbance values with complement fixation (CF) antibody titers was found (r = 0.574), the ELISA being more sensitive in detecting antibodies in acute-phase sera. For the determination of immunity, ELISA IgG values were compared with results obtained in hemagglutination-inhibition (HI) and hemolysis-in-gel (HIG) tests. Again there was a good correlation with both tests (rHI = 0.528, rHIG = 0.667). The ELISA was more sensitive than the HI and HIG test for the detection of low levels of antibodies.

Nasal secretions from 349 Austrian children under six years of age who were hospitalized for respiratory illnesses were screened for the presence of respiratory syncytial virus (RSV), parainfluenza virus 1 and 3, adenovirus and influenza A virus over a period of four years by the immunofluorescence technique. 35% of the specimens were found to be positive for one of the five viruses investigated. RSV was detected in 31% of the nasal secretions and was thus the most frequently encountered causative agent of respiratory infections in the age group investigated. RSV infections occurred almost exclusively in the winter months and were mainly associated with bronchiolitis and pneumonia. Only sporadic infections were found with one of the other viruses investigated.

An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of respiratory syncytial virus (RSV) antigens in nasopharyngeal secretions (NPS) from children with acute respiratory disease. Antisera against RSV nucleocapsids were used as immunoreagents for this test system. The results obtained by RSV antigen ELISA were compared to those of indirect immunofluorescence (IF) and tissue culture virus isolation (TC). Of the 404 NPS obtained, 278 were tested in parallel by ELISA and IF and 205 by ELISA and TC, and 89 were screened in parallel by all three methods. The sensitivity of ELISA in relation to IF was 86.7%, the specificity 95.7%. Sensitivity and specificity obtained by ELISA were 89.9% and 94.4%, respectively, compared to TC. False-negative results were obtained with all three test systems used.