Browsing by Subject "Flavivirus"

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Comparison of five serological methods for the detection of West Nile Virus antibodies
(2024) Girl, Philipp; Euringer, Kathrin; Coroian, Mircea; Mihalca, Andrei Daniel; Borde, Johannes P.; Dobler, Gerhard
The West Nile Virus (WNV), a member of the family Flaviviridae, is an emerging mosquito-borne flavivirus causing potentially severe infections in humans and animals involving the central nervous system (CNS). Due to its emerging tendency, WNV now occurs in many areas where other flaviviruses are co-occurring. Cross-reactive antibodies with flavivirus infections or vaccination (e.g., tick-borne encephalitis virus (TBEV), Usutu virus (USUV), yellow fever virus (YFV), dengue virus (DENV), Japanese encephalitis virus (JEV)) therefore remain a major challenge in diagnosing flavivirus infections. Virus neutralization tests are considered as reference tests for the detection of specific flavivirus antibodies, but are elaborate, time-consuming and need biosafety level 3 facilities. A simple and straightforward assay for the differentiation and detection of specific WNV IgG antibodies for the routine laboratory is urgently needed. In this study, we compared two commercially available enzyme-linked immunosorbent assays (anti-IgG WNV ELISA and anti-NS1-IgG WNV), a commercially available indirect immunofluorescence assay, and a newly developed in-house ELISA for the detection of WNV-NS1-IgG antibodies. All four tests were compared to an in-house NT to determine both the sensitivity and specificity of the four test systems. None of the assays could match the specificity of the NT, although the two NS1-IgG based ELISAs were very close to the specificity of the NT at 97.3% and 94.6%. The in-house WNV-NS1-IgG ELISA had the best performance regarding sensitivity and specificity. The specificities of the ELISA assays and the indirect immunofluorescence assays could not meet the necessary specificity and/or sensitivity.
Development and validation of a novel enzyme-linked immunosorbent assay for the differentiation of tick-borne encephalitis infections caused by different virus subtypes
(2025) Freimane, Zane; Dobler, Gerhard; Chitimia-Dobler, Lidia; Karelis, Guntis; Girl, Philipp; Kuzmane, Sanita; Savicka, Oksana; Erber, Wilhelm; Zavadska, Dace
Objectives: Tick-borne encephalitis (TBE) is an infection caused by the tick-borne encephalitis virus (TBEV) that can lead to symptoms of central nervous system inflammation. There are five subtypes of TBEV, three of which – European, Siberian and Far Eastern – occur in Europe. As it is thought that different subtype infections exhibit varying clinical courses and outcomes, serological differentiation of the virus subtypes is clearly important. However, to date, this has proved difficult to achieve. Methods: An ELISA format was developed based on TBE virus NS1 antigen against the European, Siberian and Far Eastern subtype. The three NS1 antigens were biotechnologically produced in a human cell line and used for ELISA coating. Sera from German (European subtype) and Russian (Siberian and/or Far Eastern subtypes) TBE patients with positive TBEV IgG were used to test the reactivity against these three NS1 antigens. Results: Testing of 23 German and 32 Russian TBEV IgG-positive sera showed that the ELISA was able to differentiate between TBEV European subtype and TBEV Siberian and Far Eastern subtype infections. Conclusions: In geographical areas where two or more TBEV subtype infections can occur, the NS1-IgG ELISA developed here constitutes an important diagnostic tool to differentiate between European subtype infections and Siberian/Far Eastern subtype infections and to use the new assay for epidemiological studies to clarify the importance of particular subtype infections in an area. Consequently, it may help to better describe and anticipate the clinical courses and outcomes of particular TBEV subtype infections.