Re-Emergence and Spread of Haemorrhagic Septicaemia in Germany: The Wolf as a Vector?

Peter Kutzer; Claudia A Szentiks; Sabine Bock; Guido Fritsch; Tibor Magyar; Christoph Schulze; Torsten Semmler; Christa Ewers

doi:10.3390/microorganisms9091999

Re-Emergence and Spread of Haemorrhagic Septicaemia in Germany: The Wolf as a Vector?

Microorganisms. 2021 Sep 21;9(9):1999. doi: 10.3390/microorganisms9091999.

Authors

Peter Kutzer¹, Claudia A Szentiks², Sabine Bock¹, Guido Fritsch³, Tibor Magyar⁴, Christoph Schulze¹, Torsten Semmler⁵, Christa Ewers⁶

Affiliations

¹ Landeslabor Berlin-Brandenburg, 15236 Frankfurt (Oder), Germany.
² Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, 10315 Berlin, Germany.
³ Department of Reproduction Management, Leibniz Institute for Zoo and Wildlife Research, 10315 Berlin, Germany.
⁴ Veterinary Medical Research Institute, Eötvös Lóránd Research Network (ELKH), 1143 Budapest, Hungary.
⁵ Microbial Genomics, Robert Koch Institute, 13353 Berlin, Germany.
⁶ Faculty of Veterinary Medicine, Institute for Hygiene and Infectious Diseases of Animals, Justus Liebig University Giessen, 35392 Giessen, Germany.

Abstract

Since 2010, outbreaks of haemorrhagic septicaemia (HS) caused by Pasteurella (P.) multocida capsular type B (PmB) emerged in Germany. In 2017, we noticed a close spatiotemporal relationship between HS outbreak sites and wolf (Canis lupus) territories. Thus, the main objectives of our study were to investigate the molecular epidemiology of German PmB-HS-isolates and to assess the role of wolves as putative vectors of this pathogen. We collected 83 PmB isolates from HS outbreaks that occurred between 2010 and 2019 and sampled 150 wolves, which were found dead in the years 2017 to 2019, revealing another three PmB isolates. A maximum-likelihood-based phylogeny of the core genomes of 65 PmB-HS-isolates and the three PmB-wolf-isolates showed high relatedness. Furthermore, all belonged to capsular:LPS:MLST genotype B:L2:ST122^RIRDC and showed highly similar virulence gene profiles, but clustered separately from 35 global ST122^RIRDC strains. Our data revealed that German HS outbreaks were caused by a distinct genomic lineage of PmB-ST122 strains, hinting towards an independent, ongoing epidemiologic event. We demonstrated for the first time, that carnivores, i.e., wolves, might harbour PmB as a part of their oropharyngeal microbiota. Furthermore, the results of our study imply that wolves can carry the pathogen over long distances, indicating a major role of that animal species in the ongoing epidemiological event of HS in Germany.

Keywords: MLST; Pasteurella multocida; core genome; domestic animals; virulence; wild boar.