[The benefit from mumps virus IgG antibody avidity testing in the population with high vaccine coverage in the context of other serological methods for laboratory diagnosis of mumps and the current epidemiological]. / Prínos avidity IgG protilátek u príusnic ve vysoce proockované populaci v kontextu s ostatními sérologickými metodami laboratorní diagnostiky príusnic a soucasnou epidemiologickou situací.

AIM: Regular vaccination against mumps resulted in a significant reduction in epidemic mumps in the Czech Republic. However, mumps cases have recently shown an upward trend, even in the vaccinated population where a considerable proportion of cases have occurred. The aim of this study was to find out, by mumps virus IgG antibody avidity testing, whether the high incidence of mumps in the vaccinated population is a result of primary or secondary vaccine failure and whether the vaccinated differ from the naturally immunised in anamnestic antibody avidity. Given the problematic laboratory diagnosis of mumps in the population with high vaccination coverage, the informative value of the detected IgM, IgA, and IgG antibodies was also considered as well as the potential of antibody avidity testing for improving laboratory diagnosis from a single sample of blood, the most commonly analysed clinical material, in patients with suspected mumps. MATERIAL AND METHODS: Sixty-four patients laboratory confirmed with mumps, whose vaccination status was known, were included in the study (groups 1 and 2). Other study groups were 30 healthy naturally immunised subjects (group 3) and 22 vaccinated children 2-4-years of age with no etiological link to the mumps virus (group 4). The avidity index (AI) was determined using the Siemens Enzygnost Anti-Mumps/IgG kit and 6M urea, able to induce the dissociation of antigen-antibody bonds proportionally to the antibody avidity. IgM, IgG, and IgA antibodies were tested using the Siemens Enzygnost Anti-Mumps/IgM and /IgG, and Mast Diagnostica Mastazyme Mumps IgA kits. The EPIDAT system served as the data source. RESULTS: The results showed that the mumps virus induces antibodies with a low AI after both vaccination, even recent, and natural immunisation. Antibodies with a high AI were only detected in convalescent sera of the vaccinated patients or in re-infected, naturally immunised persons, as a result of recent contact with the mumps virus. The comparison of the results of acute sera testing revealed that in the vaccinated patients, 56% of cases were laboratory confirmed based on IgA positivity, i.e. 20% more cases in comparison with routine detection of IgM antibodies, while of unvaccinated cases, 87% were IgA positive and 74% IgM positive. CONCLUSION: The results of mumps virus IgG antibody avidity testing suggest that the high proportion of cases in the vaccinated patients result from secondary vaccine failure, also known as waning immunity. Diagnostic benefit from antibody avidity testing has been observed in convalescent sera and/or acute sera from both vaccinated and naturally immunised patients collected from day 6 after the onset of the disease when significant increase in AI occurs.The comparison of the serological methods for the detection of IgM, IgG, and IgA antibodies in acute sera revealed that the highest percentage of mumps infection was detected by IgA antibody testing. The addition of this serological method to mumps laboratory diagnosis made the latter considerably more effective, particularly in the vaccinated patients.

[Differential diagnosis of the viral etiology of suspected mumps in a population with high vaccine coverage]. / Diferenciální diagnostika virové etiologie suspektních príusnic ve vysoce proockované populaci.

AIM: In this study, buccal swabs from patients with the clinical picture of parotitis epidemica in whom mumps virus (MV) infection was not confirmed by direct detection or serologically were tested. The aim was to detect by molecular methods nucleic acids (NAs) of other respiratory viruses possibly involved in salivary gland swelling. At the same time, paired sera, if available, were tested. MATERIAL AND METHODS: The study group consisted of 72 buccal swabs from patients of the Clinic of infectious, tropical, and parasitic diseases, Na Bulovce Hospital. Paired sera were available from ten patients. Samples were collected in 2013 to 2015. Buccal swabs were tested by PCR for the presence of NAs of adenoviruses (AdV), bocaviruses (hBoV), parainfluenza viruses of types 1-4 (HPIV), human metapneumovirus (hMPV), coronaviruses (HCoV: NL63, OC43, HKU1, and 229E), respiratory syncytial virus (RSV), influenza A virus, influenza B virus, and Epstein-Barr virus (EBV). Paired sera were screened by the complement fixation test (AdV and influenza A and B viruses), hemagglutination inhibition test (HPIV types 2 and 3), ELISA (AdV, EBV), and immunofluorescence (EBV). RESULTS: NAs from viruses other than the mumps virus were detected in 27 of 72 patients with clinical symptoms of parotitis epidemica, and serological tests revealed etiological links with parainfluenza viruses in three more cases. Overall, 30 (41.7%) of 72 patients with suspected mumps tested positive for one or more viruses from the study panel. The most commonly detected viruses were AdV 11/72 (15.3%), EBV 9/72 (12.5%), and HPIV 3/72 (4.2%), but influenza A virus (H3N2) 1/72 (1.4%) was also found. Some patients tested positive for more than one virus: 2/72 (3%) for AdV plus hBoV and 1/72 (1.4%) for HPIV plus HCoV. In addition, examination of paired sera revealed HPIV positivity in three more patients. PCR and serology detected etiological link with HPIV in six (8.3%) of 72 patients tested. CONCLUSION: In our study group, nearly 42% of patients with the clinical picture of parotitis epidemica in whom mumps virus (MV) infection was not confirmed by direct detection or serologically tested positive for viruses other than the mumps virus. Thorough laboratory diagnosis of suspected mumps in vaccinated persons is important not only for the treatment of patients and adoption of isolation and other measures, but also for a better understanding of the epidemiology of the disease and outcomes of the immunisation programmes.

[Contribution of the detection of IgA antibodies to the laboratory diagnosis of mumps in the population with a high vaccination coverage]. / Prínos stanovení protilátek IgA pro laboratorní diagnostiku príusnic ve vysoce proockované populaci.

STUDY OBJECTIVE: Serological diagnosis of epidemic mumps can be difficult in vaccinated persons, particularly due to the absence of specific IgM antibodies. The aim was to find whether adding the detection of IgA antibodies to the currently used routine serological diagnosis of mumps (detection of IgM and IgG antibodies in an acute serum sample) would make the serological diagnosis of mumps more effective in a population with a high vaccination coverage. At the same time, ELISA kits for the detection of early IgA and IgM antibodies against the mumps virus were compared and statistical analysis of the results was performed. MATERIAL AND METHODS: Sixty-four acute sera from patients with laboratory confirmed diagnosis of mumps were included in the study. Clinical specimens were collected at the onset of clinical symptoms. To test the sera, the MASTAZYME ELISA Mumps IgA kit (MAST DIAGNOSTICA, Germany) with the MASTSORB sorbent (RF and IgG) and Enzygnost Anti-Parotitis-Virus/IgM kit (Siemens, Germany) were used. A panel of 121 acute sera with no epidemiological link to mumps virus served as specificity controls for the IgA assay. The epidemiological data were derived from the EPIDAT system. The level of agreement was assessed using the McNemara test and Cohen's coefficient kappa. The Stata 9.2 software (Stata Corp LP, College Station, USA) was used for statistical analysis. RESULTS: The detection of IgA and IgM antibodies against the mumps virus yielded concordant results in 50/64 acute sera, 32 positive and 18 negative, i.e. an agreement of 78.12 %. Of the remaining 14 samples, 13 were only IgA positive and one was only IgM positive. The controls showed non-specific IgA positivity in 5/121 samples which indicates a 96% specificity. CONCLUSION: The absence of specific IgM antibodies against mumps virus is relatively often seen in vaccinated indivi-duals; nevertheless, the test is routinely used in patients with suspected active infection. The test for IgA antibodies, which is not routinely performed, significantly increased the detection rate of the disease. Based on the results of the present study, it can be concluded that the combination of the anti-mumps IgM and IgA assays increased the effectiveness of the serological diagnosis at the onset of clinical symptoms from less than 52% to nearly 72%.

[Phylogenetic and molecular analysis of A/H1N1pdm influenza viruses isolated in the epidemic season 2012/2013 from hospitalised patients with -symptoms of influenza-like illness]. / Fylogenetická a molekulární analýza viru chripky A/H1N1pdm izolovaných v epidemické sezone 2012/2013 od pacientu hospitalizovaných s príznaky ILI.

AIM: To perform phylogenetic and molecular analysis of A/H1N1pdm influenza viruses isolated in the epidemic season 2012/2013 from hospitalised patients with symptoms of influenza-like illness (ILI). MATERIAL AND METHODS: The study set included 34 strains of the A/H1N1pdm influenza virus isolated in the Czech Republic in the epidemic season 2012/2013. The strains were analysed by partial or whole-genome sequencing. The genome segments were compared at the nucleotide and amino acid levels, absolute and percentage sequence identity were determined, and phylogenetic relations were identified. The last steps were the comparison of the H1 molecule with that of the most recent vaccine strain and identification of the genotypic structure and molecular markers linked to the pathogenicity and antiviral resistance. RESULTS: Phylogenetic analysis of the H1 molecule suggested that all 34 A/H1N1pdm isolates from the 2012/2013 season in the Czech Republic should be assigned to H1 group 6 divided into sublineages 6A and 6B. The comparison of the known antigenic regions of the H1 molecule with those in the most recent vaccine strain revealed two stable changes in antigenic regions Sb and Ca1. Furthermore, sporadic mutations were identified in antigenic regions Ca2, Cb, and Sb. Genotyping revealed co-circulation of two related but clearly distiguishable genotypes of A/H1N1pdm. All isolates showed sensitivity to oseltamivir. One strain consisted of two N1 sub-populations, one oseltamivir sensitive and the other oseltamivir resistant, in nearly equimolar proportions. CONCLUSION: All A/H1N1pdm isolates from the epidemic season 2012/2013 in the Czech Republic formed a phenotypically uniform group. At the nucleotide level, the divergence was relatively more pronounced and H1 sublineages and discrete genotypes were possible to identify. H1 molecules were highly identical to those of the vaccine strain A/California/7/2009 (H1N1) which showed that the current vaccine was protective enough. All strains were sensitive to oseltamivir; however, the selection of oseltamivir resistant N1 subpopulations was observed.

[Clinical and epidemiological characteristics of patients hospitalized with severe influenza in the season 2012-2013]. / Klinické a epidemiologické charakteristiky pacientu hospitalizovaných pro tezký prubeh chripky v sezone 2012-2013.

AIM OF THE STUDY: To characterize the clinical and epidemiological features of patients hospitalized with moderate to severe influenza infection at the infec-tious diseases department of a tertiary care hospital in the epidemic season 2012-2013. MATERIAL AND METHODS: A prospective observational study of patients hospitalized with influenza infection in the season 2012-2013 was carried out at the Infectious Diseases Department, Na Bulovce Hospital in Prague. Influenza infection was diagnosed by real-time quantitative polymerase chain reaction (RT-qPCR) in nasopharyngeal swab or tracheal aspirate specimens. Demographic, clinical, and laboratory data were recorded along with the disease course and outcome. RESULTS: One hundred and ninety-nine patients, 85 females and 114 males (age median 47, range 1-87 years), were hospitalized with confirmed influenza in the epidemic season 2012-2013. Only seven of them got the influenza vaccine. Altogether 136 patients were diagnosed with influenza type A (91 with H1N1pdm, 33 with H3N2, and 12 with an unknown subtype), 66 patients with type B, and three patients with both types A and B. One hundred and eight patients (54%) had an underlying chronic disease, most often cardiovascular or pulmonary. The main symptoms of influenza were fever, cough, headache, myalgia, and arthralgia. Pneumonia was the most common complication: twenty-one patients suffered from primary viral pneumonia and 35 from bacterial pneumonia. Twenty-three patients (12%) needed intensive care. Six patients died and the leading cause of death was heart failure. CONCLUSION: During the epidemic influenza season 2012-2013, more patients were hospitalized than in the pandemic season 2009-2010. Also the proportions of complicated cases and case fatality ratios were fully comparable in both seasons. The fact that most patients were not vaccinated clearly supports the recommendation to vaccinate every year both the individuals at high risk of complications due to comorbidities and the healthy population.