Admission diagnoses of children 0-16 years of age hospitalized with influenza.

The prompt diagnosis of influenza enables the institution of antiviral therapy and adequate cohorting of patients, but scarce data are available to help clinicians correctly suspect influenza in children at the time of admission. This 16-year retrospective study assessed the main admission diagnoses of 401 children aged ≤16 years hospitalized with virologically confirmed influenza. The clinical data were derived from a systematic review of the medical records of the children. Sepsis-like illness was the main reason for admission in 52% of infants aged <6 months and in 7-16% of the older children. Respiratory symptoms accounted for 38% of admissions, and 15% of children were hospitalized due to acute neurologic conditions, primarily febrile convulsions. Wheezing or exacerbation of asthma was the primary reason for admission in 14% of children aged <3 years. No differences were observed in the admission diagnoses between children with influenza A and B infections. The main admission diagnoses vary widely in different age groups of children with influenza, and only a minority of children are hospitalized for respiratory symptoms. The leading role of sepsis-like illness in infants aged <6 months calls for increased efforts to find protective measures against influenza in this age group.

Feasibility of diagnosing influenza within 24 hours of symptom onset in children 1-3 years of age.

Diagnosing influenza at an early stage of illness is important for the initiation of effective antiviral treatment. However, especially in young children, influenza often commences with an abrupt onset of fever, with full-blown respiratory symptoms developing only later. We determined the feasibility of diagnosing influenza in young children already during the first signs of the illness. During confirmed influenza activity, we obtained nasal swabs from children aged 1-3 years who presented as outpatients within 24 hours of the onset of fever (≥38.0°C). The specimens were tested for influenza viruses with viral culture, antigen detection, PCR, and a rapid point-of-care test (Actim Influenza A&B, Medix Biochemica, Finland). In addition, follow-up specimens were obtained from a proportion of children 3-7 days later. Influenza virus was detected already within 24 hours of symptom onset in 56 of 61 (92%; 95% CI 82-97%) children in whom influenza was eventually confirmed in the laboratory. A total of 158 rapid tests performed within 24 hours of symptom onset yielded a sensitivity of 90% (95% CI 74-98%) for influenza A viruses but only 25% (95% CI 3-61%) for influenza B viruses (P < 0.001), resulting in an overall sensitivity of 77% (95% CI 61-89%) and specificity of 99% (95% CI 95-100%) for all influenza viruses. In most young children, influenza can already be accurately diagnosed within 24 hours of symptom onset. The rapid point-of-care test used was sensitive and specific for diagnosing influenza A, but its sensitivity for influenza B was limited.

Cytomegalovirus infection in early infancy: risk of induction and progression of autoimmunity associated with type 1 diabetes.

AIMS/HYPOTHESIS: Type 1 diabetes is an autoimmune disease resulting from a complex interplay between genetic and environmental factors. Cytomegalovirus (CMV) infection is one of the environmental factors implicated in the development of type 1 diabetes, although the association remains unproven. We aimed to clarify the possible correlation between CMV infections and type 1 diabetes-associated autoimmunity at the time point of autoantibody appearance in young children with HLA-conferred disease susceptibility. METHODS: CMV-specific IgG antibodies were analysed from serum samples of 169 children who had developed the first type 1 diabetes-associated autoantibody by the age of 2 years and who turned positive for multiple autoantibodies during later follow-up. We also studied 791 control children matched for sex, age and HLA genotype. The subsequent progression to clinical diabetes was analysed. The serum specimens used were collected at the time of autoantibody seroconversion or within the next 6 months. RESULTS: The frequency of CMV antibodies was similar in both study groups at the time of the first autoantibody appearance. Of the index children, 38 (22.5%) were CMV IgG antibody-positive, while the figure for control children was 206 (26.0%; p = 0.38). No association between perinatal CMV infection and progression to type 1 diabetes was observed. CONCLUSIONS/INTERPRETATION: According to these results, perinatal CMV infections are not associated with early serological signs of beta cell autoimmunity or progression to type 1 diabetes in children with diabetes risk-associated HLA genotype.

A randomized, double-blind study of the safety, transmissibility and phenotypic and genotypic stability of cold-adapted influenza virus vaccine.

BACKGROUND: Live attenuated influenza vaccine (LAIV; FluMist) is a trivalent vaccine containing cold-adapted influenza vaccine viruses that infect and replicate in cells lining the nasopharynx to induce immunity. Recovery of viruses (shedding) is measured by culture of nasal specimens. Shedding of vaccine viruses is not equated with transmission because transmission requires more virus than is detected in many nasal swabs. Previous studies with LAIV did not detect transmission to close contacts. The primary objective of this study was to estimate the probability of transmission to placebo contacts in a day care setting. METHODS: One hundred ninety-seven healthy children aged 9 to 36 months attending day care were randomized to receive vaccine or placebo. Postvaccination viral shedding, safety, genotype and phenotype of shed viruses and probability of transmission were assessed. RESULTS: Eighty percent of 98 vaccine recipients shed at least one vaccine strain. No clinically significant differences in solicited adverse events attributable to vaccine occurred; safety profiles were similar in both groups. Vaccine virus isolates retained their phenotypic characteristics (cold adaptation and temperature sensitivity) and did not revert at nucleotides known to confer an attenuating phenotype. There was one confirmed transmission of a vaccine strain to a single placebo recipient. According to the Reed-Frost model, the calculated probability of transmission to a child after contact with a single vaccinated child was 0.58% (95% confidence interval, 0-1.7%). There was no increased reactogenicity or other safety concerns in the recipient child. CONCLUSIONS: Young children in a day care setting had a high rate of shedding and a low rate of transmission. No clinically significant illness occurred among children who received vaccine or placebo or in the child to whom the vaccine virus was transmitted.

Etiology of aseptic meningitis and encephalitis in an adult population.

OBJECTIVE: To investigate the etiology of aseptic meningitis and encephalitis in an adult population using modern microbiologic methods. METHODS: Consecutive patients (ages > or =16) with aseptic meningitis or encephalitis treated in Turku University Hospital, Finland, during 1999 to 2003 were included in the study. Microbiologic tests were performed, including CSF PCR tests for enteroviruses, herpes simplex virus (HSV) 1, HSV-2, and varicella zoster virus (VZV), as well as serum and CSF antibody analysis for these viruses. Antibody testing was also performed for other pathogens commonly involved in neurologic infections. Virus culture was performed on CSF, fecal, and throat swab specimens. RESULTS: Etiology was defined in 95 of 144 (66%) patients with aseptic meningitis. Enteroviruses were the major causative agents (26%), followed by HSV-2 (17% of all, 25% of females) and VZV (8%). Etiology was identified in 15 of 42 (36%) patients with encephalitis, VZV (12%), HSV-1 (9%), and tick-borne encephalitis virus (9%) being the most commonly involved pathogens. Etiologic diagnosis was achieved by PCR in 43% of the patients with meningitis and in 17% of those with encephalitis. CONCLUSIONS: Enteroviruses and HSV-2 are the leading causes of adult aseptic meningitis, and PCR is of diagnostic value. However, in most cases of encephalitis, the etiology remains undefined.

Bronchoalveolar lavage in immunocompromised patients with haematological malignancy--value of new microbiological methods.

PURPOSE: To assess the usefulness of new culture-independent microbiological methods to analyse bronchoalveolar lavage (BAL) fluid from haematological patients with clinical pneumonia. PATIENTS AND METHODS: Results of 135 BALs from 122 disease episodes in 99 patients treated between 1996 and 2002 were retrospectively analysed. Forty-three patients had undergone haematopoietic stem cell transplantation and 56 patients had been treated with conventional chemotherapy for haematological malignancy. In addition to conventional microbiological methods, polymerase chain reaction (PCR) tests for Pneumocystis carinii, cytomegalovirus (CMV), Legionella sp., mycobacterium, Mycoplasma pneumoniae, and Chlamydia pneumoniae and the Aspergillus antigen test were performed. RESULTS: Three (2.2%) quantitative and four (3.0%) special bacterial cultures gave an aetiological diagnosis. A respiratory virus was isolated in 10 episodes (8.2%). The diagnostic yield increased to 35.6% (48 of 135) by other methods. The P. carinii PCR test was positive in 21 of 24 patients with P. carinii pneumonia, being the only microbiological indication of P. carinii in four cases. The CMV PCR test was positive in 18 patients, but in 14 patients the clinical significance of the finding remained unproven. The Aspergillus antigen test was positive in seven of nine patients with aspergillosis, being the only microbiological indication of Aspergillus in three cases. The result of BAL indicated commencement of specific antimicrobial treatment in 27 episodes (22.1%). CONCLUSION: The contribution of new culture-independent methods to the total diagnostic yield was of note. Among these methods, the P. carinii PCR and Aspergillus antigen tests proved the most valuable, while the CMV PCR test was not clinically useful.

Hospital admission of high risk infants for respiratory syncytial virus infection: implications for palivizumab prophylaxis.

OBJECTIVES: To determine the rates of hospital admission for respiratory syncytial virus (RSV) infection among children born at different gestational ages. To assess the theoretical impact of palivizumab prophylaxis on admissions for RSV infection. DESIGN: Retrospective cohort study of children born in 1991-2000. SETTING: Tertiary care university hospital. METHODS: Data on all children born during the 10 year period were combined with information on laboratory confirmed RSV infections in these children until the end of 2002. The theoretical impact of palivizumab on RSV associated admissions was estimated by applying the current recommendations for prophylaxis to the study population and using the observed rates of admission in the calculations. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Rates of RSV infection and hospital admission in different subgroups of children. RESULTS: Children with chronic lung disease (CLD) were admitted for RSV infection at a rate of 12.0%. The corresponding rates in children born at

Role of cytoskeleton components in measles virus replication.

Cellular factors have been indicated to be essential for the replication of Measles virus (MV), but the exact roles of these components are, however, not understood in detail. In this study, we investigated the role of actin and tubulin in productive MV infection by inducing disassembly of the microfilaments and microtubules. Vero cells were treated with latrunculin-A, which sequesters actin monomers, or nocodazole, which breaks the microtubules. The disruption of either of the structures efficiently inhibited the maturation of new infectious virus. Interestingly, virus spreading to neighboring cells still occurred by fusion and large syncytia typical for MV infection appeared. We also investigated a possible role for proteins of the ERM-family. Our results support an important role for actin filaments and microtubules for efficient MV replication.

Prevalence of Sindbis-related (Pogosta) virus infections in patients with arthritis.

OBJECTIVE: To determine the role of Pogosta virus as a triggering infection in non-specific arthritis. METHODS: Serum samples of 142 patients with acute arthritis were screened for the evidence of Pogosta virus infection. Serological tests for Chlamydia trachomatis, salmonella, parvovirus B19, and Borrelia burgdorferi were also carried out. As verified later, 78 of the patients had rheumatoid arthritis and 63 seronegative poly- or oligoarthritis, while one had systemic lupus erythematosus. RESULTS: In the early stage of the joint symptoms 4 patients with rheumatoid arthritis, 1 with seronegative polyarthritis and 1 with systemic lupus erythematosus had recent Pogosta virus infection. Four of them had probably had Pogosta disease at the time of the onset of arthritis. In 11 patients with a diagnosis of seronegative arthritis, serological evidence of preceding infection due to salmonella or Chlamydia trachomatis was found, strongly suggesting classical reactive arthritis in these cases. CONCLUSIONS: Our study suggests that also a Sindbis virus infection may be associated both to an acute joint inflammation as a part of Pogosta disease or chronic arthritis. At present, this possibility still needs further research.

The prevalence of antibodies against Sindbis-related (Pogosta) virus in different parts of Finland.

OBJECTIVE: To study the occurrence of Sindbis-related (Pogosta) disease in Finland by serological means. METHODS: A total of 2250 serum samples from five different areas were included in the study. Four hundred samples were collected from healthy blood donors and 1850 samples from patients who were suspected to have some viral infection. Antibodies of IgG and IgM classes against Pogosta virus were measured. RESULTS: Eleven per cent of 2250 samples were positive for IgG and 0.6% were positive for IgM class antibodies against Pogosta virus. The antibody prevalence in Finland was almost equally distributed, being highest in western Finland (17%) and lowest in southern and northern Finland (9%). Of all samples with IgG class antibodies, 25% were taken from children under 10 yr of age. CONCLUSIONS: The prevalence of antibodies against Pogosta virus was much higher than we expected. Additionally, they were detected from all locations studied and not only in eastern Finland, which has been thought to be the main endemic area for this disease. Pogosta disease has been considered to affect mainly middle-aged persons, but our results indicate a high prevalence also among children.

Measles virus induces apoptosis in uninfected bystander T cells and leads to granzyme B and caspase activation in peripheral blood mononuclear cell cultures.

BACKGROUND: Measles causes lymphopenia and depresses cell-mediated immunity, but the mechanisms of immunosuppression and cell loss are poorly known. METHODS: We have used an in vitro model of measles virus (MV)-infected peripheral blood mononuclear cells (PBMCs) and phytohaemagglutinin-stimulated PBMCs in order to assess MV-leucocyte interactions. Cell population undergoing apoptosis was measured by flow cytometry and Annexin-V-fluos staining. The expression of Fas, FasL, TNRF1, and Bcl-2 was analyzed by flow cytometry and Western blotting, and activation of caspase cascade was measured using a colourimetric caspase substrate set. The effects of caspase inhibitors were detected by flow cytometry. RESULTS: Measles virus was able to infect monocytes, but interestingly induced apoptosis in uninfected T cells, indicating that induction of apoptosis in T cells is mediated by MV-infected adherent cells. Only 1% of T cells contained MV antigen day 3 p.i. Interestingly the percentage of early apoptotic T cells at the same time was 35%, showing that apoptosis was not the result of MV infection in T cells. Measles virus-induced Fas but not FasL or TNFR1 expression on PMBC, as well as activation of granzyme B and caspase cascade. Simultaneously, overexpression of Bcl-2 protein was detected. Caspase inhibitor decreased the amount of apoptotic T cells. CONCLUSION: Measles virus-infected monocytes induce apoptosis in uninfected T cells, suggesting that infected monocytes probably interact via cell-surface molecules with uninfected T cells and induce apoptosis by indirect mechanisms. Apoptosis of the lymphocytes may contribute to the pathogenesis of MV-induced immunosuppression and cell loss.

Measles virus enhances the expression of cellular immediate-early genes and DNA-binding of transcription factor AP-1 in lung epithelial A549 cells.

In this work we investigated the effect of measles virus (MV) infection on the expression of immediate-early genes junB, c-jun and c-fos mRNA as well as AP-1 DNA-binding activity in the lung epithelial-like adenocarcinoma cell line A549. The transcription factor AP-1, which is a group of dimeric complexes of the Fos and Jun family proteins, is an important regulator in many cellular responses to different extracellular stimuli. Membrane cofactor protein CD46, which acts as a receptor for laboratory-adapted and vaccine strains of MV, has been reported to associate with beta1 integrin molecules, which are known to trigger signaling events and activate immediate-early genes. The expression of junB and c-jun mRNA was rapidly induced by MV. It was observed already at 1 h postinfection and detected again at the later phase of infection. Moreover, the expression of c-fos mRNA seemed to be weak and transient. The early induction was apparently associated with MV binding and CD46 clustering, whereas the later induction coincided with virus replication. MV infection also enhanced the activation of AP-1 DNA-binding. Our results suggest that changes in the expression of immediate-early genes and in the activation of AP-1 DNA-binding may have an important role in many cellular events detected in MV-infected cells.

Development of enzyme immunoassays to detect salivary sIgA to Chlamydia pneumoniae and Mycoplasma pneumoniae.

Enzyme immunoassays (EIAs) for the detection of secretory IgA antibody (sIgA) to Chlamydia pneumoniae and Mycoplasma pneumoniae from saliva are described. The presence of salivary sIgA in healthy laboratory personnel (mean age 40, range 25-62 years) was detected using conjugates of antibodies directed against secretory and alpha-chain domains. The EIA results for the detection of C pneumoniae sIgA antibodies were confirmed by a sensitive microimmunofluorescence method used as a reference. Circulating IgA antibody levels in sera were also determined using commercial EIAs. Secretory IgA antibodies to both C pneumoniae and M. pneumoniae were detectable only from persons with positive or borderline circulating IgA antibodies. Moreover, C. pneumoniae sIgA was found in the saliva of a clinically healthy person whose serum IgA antibody levels had been constantly elevated during the past 7 years. In conclusion, because of their specificity the described methods could be used in further delineation of the role of anti-C pneumoniae and M. pneumoniae sIgA antibodies. However, owing to the unexpected high frequency of these antibodies in saliva of clinically healthy persons, it seems unlikely that a single sIgA measurement from saliva is diagnostically more powerful than a single IgA measurement from serum to study and interpret the involvement of these pathogens in chronic respiratory diseases.

Multicenter evaluation of the novel enzyme immunoassay based on P1-enriched protein for the detection of Mycoplasma pneumoniae infection.

The aim of the study was to evaluate new Mycoplasma pneumoniae IgG, IgA and IgM EIA methods based on the enrichment of P1-protein (ThermoLabsystems, Helsinki, Finland) (L) for the detection of acute infection. This evaluation was performed in two independent routine clinical microbiology laboratories. The first laboratory used samples preselected by IgG and IgM Platelia enzyme immunoassay (P) and the second used samples preseleced by Serion ELISA Classic M. pneumoniae IgG, IgM (V). The L method was also compared to the FDA approved method of ImmunoWell M. pneumoniae IgG and IgM (G). When the agreement of two methods was applied as a serologic criteria for an acute infection, the following ratios of acute to nonacute infection were calculated 32/86 (totally 118) in the first and 20/72 (totally 92) in the second laboratory. In the first laboratory, the corresponding ratios by methods were 35/83 (sensitivity 100%, specificity 96.5%), 31/87 (sensitivity 97%, specificity 100%), and 55/63 (sensitivity 100%, specificity 79%) for the L, P and G methods, respectively. In the second laboratory, the ratios were 21/71 (sensitivity 100%, specificity 99%), 16/76 (sensitivity 83%, specificity 100%), and 53/39 (sensitivity 100, specificity 69%) for the L, V and G methods, respectively. Taking into account that the tested sample material was preselected by the P and V methods, which may have introduced some bias in their favor, the newly developed L method utilizing P1-enriched protein was found reliable for serodiagnosis of acute M. pneumoniae infection. The method G was the least specific in detection of acute infection.

Parainfluenza virus type 3 infections in a hematology unit.

Parainfluenza virus type 3 (PIV3) is associated with a high mortality rate in BMT recipients with lower respiratory tract infections. We describe nine patients with hematological malignancies (five having undergone either allogeneic or autologous stem cell transplantation) identified as having PIV3 infection during a 2-month period in a Hematology Unit. Four patients with infiltrates on chest radiograph received intravenous ribavirin therapy; all survived. The infection was community-acquired in two patients, while nosocomial origin of the disease was evident, or presumed, in the remaining seven. The policy implemented to control the spread of PIV3 was as follows: (1) nasopharyngeal samples for antigen detection were obtained from all patients presenting with respiratory symptoms; (2) all diagnosed (or suspected) PIV3-positive hematological patients were nursed following contact isolation precautions, preferably in the Infectious Diseases Unit; and (3) staff were given further education on hospital hygiene. Our experience shows that it may be possible to avoid mortality for PIV3 lower respiratory tract infection in immunocompromised patients by early commencement of intravenous ribavirin. It is also possible, even without closing the ward, to contain nosocomial spread of PIV3 by implementing systematic nasopharyngeal sampling for rapid diagnostics, and by strict adherence to cohorting and contact isolation precautions.

Cell membrane-associated measles virus components inhibit antigen processing.

Measles virus (MV)-induced immune suppression is an important reason for MV-associated mortality and morbidity. Despite numerous studies, the mechanisms of immune suppression still remain poorly defined. In the present study we analyzed the effect of MV components on the T-cell recognition of specific non-MV antigens. We demonstrated that even inactivated MV could inhibit the presentation of unprocessed protein antigen to specific T cells, whereas MV did not affect the responses of specific T cells to representative synthetic peptide epitopes derived from complex antigens. The inhibition was induced by MV-infected cell membranes. The kinetics of the MV-dependent inhibition suggested an impaired antigen processing in mononuclear cells as addition of MV-infected cell debris 4 h after the beginning of cell cultures no longer inhibited T-cell responsiveness.

Measles virus activates NF-kappa B and STAT transcription factors and production of IFN-alpha/beta and IL-6 in the human lung epithelial cell line A549.

Epithelial cells of the respiratory tract are the primary targets of measles virus (MV) infection. In this work we have studied the effect of MV infection on the activation of transcription factors nuclear factor (NF)-kappa B and signal transducer and activator of transcription (STAT) and the production of cytokines in the lung epithelial A549 cell line. NF-kappa B and STAT activation were induced by MV in A549 cells as analyzed by electrophoretic mobility shift assay. NF-kappa B activation was rapid and it was not inhibited by the protein synthesis inhibitor cycloheximide, suggesting that MV directly activates NF-kappa B. In contrast, Stat1, Stat3, and interferon-stimulated gene factor 3 (ISGF3) DNA binding was induced by MV infection with delayed kinetics compared to NF-kappa B activation. MV infection also resulted in an efficient interferon (IFN)-alpha/beta and interleukin-6 production. Cycloheximide and neutralizing anti-IFN-alpha/beta antibodies inhibited MV-induced activation of Stat1, Stat3, and ISGF3 DNA binding in A549 cells. In conclusion, the results suggest that MV infection activates transcription factors involved in the initiation of innate immune responses in epithelial cells by two different mechanisms: directly by leading to NF-kappa B activation and indirectly via IFN-alpha/beta leading to STAT activation.