Seroprevalence and Risk Factors for Equine West Nile Virus Infections in Eastern Germany, 2020

Stefanie Ganzenberg; Michael Sieg; Ute Ziegler; Martin Pfeffer; Thomas W Vahlenkamp; Uwe Hörügel; Martin H Groschup; Katharina L Lohmann

doi:10.3390/v14061191

Seroprevalence and Risk Factors for Equine West Nile Virus Infections in Eastern Germany, 2020

Viruses. 2022 May 30;14(6):1191. doi: 10.3390/v14061191.

Authors

Stefanie Ganzenberg¹, Michael Sieg², Ute Ziegler³, Martin Pfeffer⁴, Thomas W Vahlenkamp², Uwe Hörügel⁵, Martin H Groschup³, Katharina L Lohmann¹

Affiliations

¹ Department for Horses, Faculty of Veterinary Medicine, Leipzig University, 04103 Leipzig, Germany.
² Institute of Virology, Faculty of Veterinary Medicine, Leipzig University, 04103 Leipzig, Germany.
³ Friedrich-Loeffler Institut (FLI), Federal Research Institute for Animal Health, Institute of Novel and Emerging Infectious Diseases, 17493 Greifswald-Insel Riems, Germany.
⁴ Institute of Animal Hygiene and Veterinary Public Health, Faculty of Veterinary Medicine, Leipzig University, 04103 Leipzig, Germany.
⁵ Animal Diseases Fund Saxony, Pferdegesundheitsdienst, 01099 Dresden, Germany.

Abstract

West Nile virus (WNV) infections were first detected in Germany in 2018, but information about WNV seroprevalence in horses is limited. The study's overall goal was to gather information that would help veterinarians, horse owners, and veterinary-, and public health- authorities understand the spread of WNV in Germany and direct protective measures. For this purpose, WNV seroprevalence was determined in counties with and without previously registered WNV infections in horses, and risk factors for seropositivity were estimated. The cohort consisted of privately owned horses from nine counties in Eastern Germany. A total of 940 serum samples was tested by competitive panflavivirus ELISA (cELISA), and reactive samples were further tested by WNV IgM capture ELISA and confirmed by virus neutralization test (VNT). Information about potential risk factors was recorded by questionnaire and analyzed by logistic regression. A total of 106 serum samples showed antibodies against flaviviruses by cELISA, of which six tested positive for WNV IgM. The VNT verified a WNV infection for 54 samples (50.9%), while 35 sera neutralized tick-borne encephalitis virus (33.0%), and eight sera neutralized Usutu virus (7.5%). Hence, seroprevalence for WNV infection was 5.8% on average and was significantly higher in counties with previously registered infections (p = 0.005). The risk factor analysis showed breed type (pony), housing in counties with previously registered infections, housing type (24 h turn-out), and presence of outdoor shelter as the main significant risk factors for seropositivity. In conclusion, we estimated the extent of WNV infection in the resident horse population in Eastern Germany and showed that seroprevalence was higher in counties with previously registered equine WNV infections.

Keywords: Germany; Usutu virus; West Nile virus; epidemiology; horses; risk factors; seroprevalence; tick-borne encephalitis virus.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Antibodies, Viral
Encephalitis Viruses, Tick-Borne*
Enzyme-Linked Immunosorbent Assay
Horse Diseases* / epidemiology
Horses
Humans
Immunoglobulin M
Risk Factors
Seroepidemiologic Studies
West Nile Fever* / epidemiology
West Nile Fever* / veterinary
West Nile virus*

Substances

Antibodies, Viral
Immunoglobulin M

Grants and funding

This research was funded by Boehringer Ingelheim Vetmedica GmbH, Germany (funding number: 493469). The funding body had no role in the design of the study, nor in the implementation of the experiment, or the collection, analysis, or interpretation of the data; in the writing of the manuscript, or in the decision to publish the results.