Chikungunya virus infections among travellers returning to Spain, 2008 to 2014.

Since the first documented autochthonous transmission of chikungunya virus in the Caribbean island of Saint Martin in 2013, the infection has been reported within the Caribbean region as well as North, Central and South America. The risk of autochthonous transmission of chikungunya virus becoming established in Spain may be elevated due to the large numbers of travellers returning to Spain from countries affected by the 2013 epidemic in the Caribbean and South America, as well as the existence of the Aedes albopictus vector in certain parts of Spain. We retrospectively analysed the laboratory diagnostic database of the National Centre for Microbiology, Institute of Health Carlos III (CNM-ISCIII) from 2008 to 2014. During the study period, 264 confirmed cases, of 1,371 suspected cases, were diagnosed at the CNM-ISCIII. In 2014 alone, there were 234 confirmed cases. The highest number of confirmed cases were reported from the Dominican Republic (n = 136), Venezuela (n = 30) and Haiti (n = 11). Six cases were viraemic in areas of Spain where the vector is present. This report highlights the need for integrated active case and vector surveillance in Spain and other parts of Europe where chikungunya virus may be introduced by returning travellers.

Imported Human West Nile Virus Lineage 2 Infection in Spain: Neurological and Gastrointestinal Complications.

We report the first human case of West Nile virus (WNV) lineage 2 infection imported to Spain by a traveler returning from Romania. Serum, cerebrospinal fluid and urine samples were analyzed and West Nile virus infection was identified by PCR and serological tests. The patient developed fever, diarrhea and neurological symptoms, accompanied by mild pancreatitis, described previously in very few cases as a complication of WNV infection and by alithiasic cholecystitis. Viral RNA was detected in urine until 30 days after the onset of symptoms and neutralizing antibodies were detected at very low titers. The phylogenetic analysis in a fragment of the NS5 gene of the virus showed a homology with sequences from WNV lineage 2 belonging to the monophyletic Central/Southern European group.

Evaluation of the LIAISON XL Zika Capture IgM II for the Diagnosis of Zika Virus Infections.

The aim of this study is to evaluate the performance characteristics of the LIAISON XL Zika Capture IgM II. For this purpose we tested 128 samples obtained from recent infections caused by the Zika (ZIKV; 74 samples), dengue (DENV; 10 samples), chikungunya (CHIK V; 11 samples), rubella (RUBV; 10 samples) and measles (MeV; 10 samples) viruses, as well as human parvovirus B19 (HPVB19; 13 samples). The results of the assay under evaluation are compared with those obtained from an indirect immunofluorescence (IIF) assay, and the discrepancies are resolved by considering other laboratory results (PCR and a plaque-reduction neutralization test). The LIAISON showed excellent sensitivity (100%). The specificity (91.25%) was hampered by some false-positive results in recent dengue virus, chikungunya virus, measles virus and human parvovirus B19 infections. The method evaluated is adequate, but the low specificity makes it necessary to consider the clinical and epidemiological contexts of patients, as well as other laboratory results.

The Application and Interpretation of IgG Avidity and IgA ELISA Tests to Characterize Zika Virus Infections.

In the absence of viremia, the diagnostics of Zika virus (ZIKV) infections must rely on serological techniques. In order to improve the serological diagnosis of ZIKV, ZIKV-IgA and ZIKV-IgG avidity assays were evaluated. Forty patients returning from ZIKV endemic areas, with confirmed or suspected ZIKV infections were studied. Samples were classified as early acute, acute and late acute according to the number of days post illness onset. Low avidity IgG was only detected at acute and late acute stages and IgA mostly at the early acute and acute stages. The date of sampling provides useful information and can help to choose the best technique to use at a determined moment in time and to interpret low avidity IgG and IgA results, improving the serological diagnosis of ZIKV.

Comparison of chemiluminescent immunoassay and ELISA for measles IgG and IgM.

In the context of measles elimination, the identification of recent infections is important for clinical laboratories. Serological diagnosis is achieved by detecting specific IgG and IgM. Recently an automated chemiluminescent immunoassay (CLIA) (Liaison, DiaSorin, Italy) has been used to quantify the measles antibody. The aim of this study was to compare this assay with Enzygnost ELISA (Siemens, Germany), with final classification of discrepancies by indirect immunofluorescence (Euroimmun, Germany). For measles IgM, 204 sera were analyzed: 50 IgM-positive, 104 IgM-negative/IgG-positive, and 50 from other viral infections (B19V, rubella, mumps, CMV, and EBV). For the measles IgG assay, 162 samples were tested: 106 were positive and 56 were negative. For measles IgM, the sensitivity and specificity of CLIA against ELISA were 94% (95% CI: 83.2-98.6) and 100% (95% CI: 97.1-100), respectively; the corrected figures after the final classification of discrepancies were 100% (95% CI: 91.0-100) and 99.4% (95% CI: 96.1-100), respectively. In relation to IgG, the sensitivity and specificity of CLIA against ELISA were, respectively, 97.2% (95% CI: 91.7-99.4) and 92.9% (95% CI: 82.5-97.7), and 95.5% (95% CI: 89.5-98.3) and 100% (95% CI: 91.8-100) after the final classification. CLIA showed excellent sensitivity and specificity in detecting measles IgG and IgM antibodies, eliminating the need to aliquot specimens before carrying out the assay.

Comparative evaluation of tests for detection of parvovirus B19 IgG and IgM.

The aim of this study was to evaluate enzyme immunoassays (EIA) (Euroimmun, Lübeck, Germany) and chemiluminiscent immunoassays (CLIA) (Diasorin, Saluggia, Italy) in their application to detect B19V-IgM and -IgG. For this purpose, one hundred and ninety samples were studied. Of them, 101 came from recent infection cases (B19V-specific IgM (86) and/or PCR (87), 42 from past infections, 18 from non-infected, and 29 from other viral recent infections (Epstein-Barr virus, measles, and rubella). Samples were characterized by capture (for IgM), or indirect (for IgG) EIA (Biotrin, Dublin, Ireland); indeterminate samples were classified by indirect immunofluorescence (IIF) (Biotrin). All the samples were used for testing IgM assays, and all but the cases from other viral infections were used for IgG tests. For IgM, CLIA, and EIA identified 76 and 62 of 86 IgM positives, respectively (sensitivity 88.4% and 72.1%). Considering B19V IgM negative samples, negative result was obtained in 95 and 92 of 104, being the specificity values of CLIA and EIA 91.3% and 88.5%, respectively. For IgG, CLIA and EIA identified correctly 114 and 115 of the 122 positive samples (sensitivity 93.4% and 94.3%, respectively), and 39 and 36 of 39 negative samples (specificity 100% and 92.3%). As conclusion, CLIA methods can be used in clinical laboratories as adequate alternatives to the well-established Biotrin EIAs.

[Comparison of five commercial assays for the detection of Legionella pneumophila antigens in urine]. / Comparación de cinco ensayos comerciales para la detección de antígenos de Legionella pneumophila en orina.

OBJECTIVE: Antigenuria detection is the main approach for diagnosing Legionella infections. The aim of this study was to compare 5 commercially available methods for detecting Legionella pneumophila soluble antigens in urine. METHODS: Seventy-one urine samples were tested, 62 from patients with bacterial infection and 9 from patients with respiratory syncytial virus infection. All samples were assayed for the presence of L. pneumophila by immunoenzymatic (ELISA) (Binax and Bartels), and immunochromatographic (IC) (Binax, SAS and Uni-Gold) methods. RESULTS: Identical results (35 positive and 17 negative) were obtained by the 5 assays in 52 samples (73.2%). Samples showing discrepant results were classified by the majority criterion, and/or other laboratory results (serology), and/or epidemiological findings. On this basis, 51 samples were ultimately classified as positive, and 20 as negative. Sensitivity values of ELISA-Binax, ELISA-Bartels, IC-Binax, IC-SAS and IC-Uni-Gold were 80.4, 100, 82.4, 86.3, and 70.6%, respectively. Corresponding values for specificity were 90, 95, 100, 95 and 100%. CONCLUSIONS: The results indicate that the methods compared are all adequate for diagnosing Legionella infection, although some have certain limitations regarding sensitivity.

Comparación de cinco ensayos comerciales para la detección de antígenos de Legionella pneumophila en orina / Comparison of five commercial assays for the detection of Legionella pneumophila antigens in urine

Objetivo: la detección de antigenuria es la herramienta fundamental para el diagnóstico de la infección por Legionella. El objetivo es comparar cinco métodos disponibles comercialmente para la detección de antígenos solubles de Legionella pneumophila en orina. Métodos: se han estudiado 71 muestras de orina procedentes de casos de infección por la bacteria (62 muestras) o de casos de infección por virus respiratorio sincitial (9 casos). Las muestras se han analizado para la detección de antígenos solubles de L. pneumophila por métodos inmunoenzimáticos (ELISA) (Binax y Bartels) e inmunocromatográficos (IC) (Binax, SAS y Uni-Gold). Resultados: se ha obtenido resultado idéntico en los cinco análisis en 52 muestras (73,2%) (35 positivas y 17 negativas). Las muestras con resultado discrepante se han clasificado por el criterio de la mayoría de los resultados y/u otros resultados de laboratorio (serología) y/o antecedentes epidemiológicos. Así han sido finalmente clasificadas como positivas 51 muestras, y como negativas, las 20 restantes. Los valores de sensibilidad de ELISA-Binax, ELISA-Bartels, IC-Binax, IC-SAS e IC-Uni-Gold han sido del 80,4, el 100, el 82,4, el 86,3 y el 70,6%, respectivamente. Los valores correspondientes de especificidad han sido del 90, el 95, el 100, el 95 y el 100%. Conclusiones: los resultados indican que los métodos evaluados son adecuados al diagnóstico de la infección por Legionella, con algunas reservas en cuanto a la sensibilidad de alguno de ellos (AU)

Objective: Antigenuria detection is the main approach for diagnosing Legionella infections. The aim of this study was to compare 5 commercially available methods for detecting Legionella pneumophila soluble antigens in urine. Methods: Seventy-one urine samples were tested, 62 from patients with bacterial infection and 9 from patients with respiratory syncytial virus infection. All samples were assayed for the presence of L. pneumophila by immunoenzymatic (ELISA) (Binax and Bartels), and immunochromatographic (IC) (Binax, SAS and Uni-Gold) methods. Results: Identical results (35 positive and 17 negative) were obtained by the 5 assays in 52 samples (73.2%). Samples showing discrepant results were classified by the majority criterion, and/or other laboratory results (serology), and/or epidemiological findings. On this basis, 51 samples were ultimately classified as positive, and 20 as negative. Sensitivity values of ELISA-Binax, ELISA-Bartels, IC-Binax, IC-SAS and IC-Uni-Gold were 80.4, 100, 82.4, 86.3, and 70.6%, respectively. Corresponding values for specificity were 90, 95, 100, 95 and 100%. Conclusions: The results indicate that the methods compared are all adequate for diagnosing Legionella infection, although some have certain limitations regarding sensitivity (AU)