Histomonosis in German turkey flocks: possible ways of pathogen introduction

ABSTRACT

Histomonosis has become an important disease of turkeys since the ban of effective feed additives and therapeutics. Some critical risk factors for pathogen introduction into a farm have already been identified but open questions remain. Therefore, a retrospective case–control-study was used to identify the most significant risk factors for Histomonas (H.) meleagridis-introduction into a turkey farm. A total of 113 questionnaires were collected from 73 control-farms and 40 Histomonas-positive case-farms in Germany between 20 April 2021 and 31 January 2022. The data were analysed for possible risk factors by descriptive and univariate, single- and multi-factorial analysis. The presence of earthworms, snails and beetles, as vectors of H. meleagridis, as well as the proximity to other poultry-keeping farms in addition to a frequent observation of wild birds nearby the turkey farm, showed the highest risk potential for histomonosis outbreaks. Furthermore, poor biosecurity measures seem to have increased the probability for an outbreak. Insufficient climate management, straw as litter material and an inadequate litter refill frequency might have promoted a favourable humidity for vector- or pathogen survival providing important areas for improved disease control measures in the future.

RESEARCH HIGHLIGHTS

• A retrospective case–control-study was conducted to identify impactful risk factors for a H. meleagridis introduction.

• The probability of a histomonosis outbreak was increased by the presence of vectors and reservoirs nearby a farm.

• Impactful risk factors concerning biosecurity measures, climate and litter management were identified.

KEYWORDS:

• Histomonas meleagridis
• histomonosis
• epidemiology
• case–control-study
• risk factor
• turkey

Acknowledgements

The authors would like to thank the association of German poultry industry (ZDG, Berlin, Germany), especially Eva-Maria Gefeller and Marie-Louise Schneider for their support in advertising our survey. Our thanks need to be given to Christoph Üffing (Veterinarian, Hopsten, Germany), Ronald Günther (Veterinarian for commercial poultry and advice, Magdeburg, Germany), Bettina Schneider and Fritjof Freise (IBEI, University of Veterinary Medicine, Foundation, Hannover, Germany) for their support in the development of our survey and in statistical analysis. In addition, we would like to thank all cooperation partners for distributing our survey.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the QS-Wissenschaftsfonds and QS-Fachgesellschaft Geflügel GmbH (Bonn, Germany). This Open Access publication was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – 491094227 “Open Access Publication Costs” and the University of Veterinary Medicine Hannover, Foundation.