Wissenschaftlich

L. Könenkamp, U. Ziegler, T. Naucke, M.H. Groschup, I. Steffen

Transboundary and Emerging Diseases, June 2022 69(7)

Abstract: Flavivirus diagnostics are complicated by substantial cross-reactivity of antibodiesbetween different flavivirus species. This is of particular importance in regions withmultiple endemic flaviviruses in co-circulation. Tick-borne encephalitis virus (TBEV) isthe causative agent of tick-borne encephalitis, the most common infection of the cen-tral nervous system in endemic regions of Europe and Asia. Since 2018, the relatedWest Nile virus (WNV) has spread to Germany where its geographic distributionoverlaps with TBEV endemic regions. Besides humans, various animal species aresusceptible to TBEV and WNV infection. To compare antibody responses againstthese flaviviruses and test for cross-reactivity, we developed a multi-species luciferaseimmunoprecipitation system antibody detection assay for several different antigens.We performed a serosurvey of 682 dogs from five different European countries todetect antibodies against TBEV and WNV. Twelve specimens were positive for TBEVNS1 only and seven for WNV NS1 only. Two specimens were reactive to both NS1antigens and another two were equivocal for WNV NS1. Interestingly, 89.5% of pos-itive specimens had TBEV/WNV or WNV/TBEV signal ratios of 10 to >300 betweenindividual NS1 antigens, allowing for a clear distinction between the two viruses. Theremaining 10.5% of reactive specimens showed a five- to 10-fold difference betweenthe two viruses and included possible dual exposures to both viruses. In contrast,equivocal samples showed low signal ratios between the NS1 antigens, suggestingunspecific reactivity. Based on these data, we found the NS1 protein to be a suit-able antigen to distinguish between TBEV- and WNV-specific antibodies in dogs withsensitivity and specificity similar to virus neutralization tests.

Download (extern)

S. Oerther, H. Jöst, A. Heitmann, R. Lühken, A. Krüger, I. Steinhausen, C. Brinker, S. Lorentz, M. Marx, J. Schmidt‑Chanasit, T. Naucke and N. Becker

Parasites Vectors 13, 173 (2020)

Abstract
Background: Vector‑borne diseases (VBD) are of growing global importance. Sand flies are potential vectors forphleboviruses (family Phenuiviridae) including Toscana virus (TOSV), Sicilian virus, Sandfly fever, Naples virus, and Leishmania parasites in Europe. To date, only two phlebotomine species have been recorded for Germany: Phlebotomus perniciosus and Phlebotomus mascittii. This study updates the distribution and abundance of the two occurringspecies.

Methods: An entomological field study was carried out during 2015–2018 to assess the abundance of sand flies inSouthwest Germany within the federal states Baden‑Wuerttemberg (BW) and Rhineland‑Palatinate (RLP). A total of 176 collection sites were examined using CDC light traps.

Results: A total of 149 individuals of P. mascittii were collected. During 2015–2018, P. mascittii was found at all sitesknown positive from previous studies and was detected at 15 additional sites previously unknown for the presenceof sand flies. Although the environment has changed considerably in 30 years, no significant difference in sand flydynamics and distribution was found. Phlebotomus perniciosus has only been trapped once since 2001.

Conclusions: This study showed that sand flies occur in different areas in Southern Germany where they had notbeen recorded previously. Therefore, it can be assumed that they are more widespread than expected. In addition,sand flies could be found over several years at the same trapping sites, indicating population stability. This supportsthe need for continued surveillance of possible vector populations and urgent clarification of the vector competenceof P. mascittii.

Download (extern)