Zoonotic pathogens in equids in Central Europe: a systematic review

Equids serve diverse roles in contemporary society. Their use as companion animals, in sports, transportation, and food production brings them into close contact with humans, creating potential zoonotic risks. This review had two objectives: (i) to catalogue zoonotic pathogens detected in equids across Central Europe, and (ii) to analyse research trends and collaborations in equid zoonosis studies within the region. We conducted a systematic literature search following PRISMA guidelines to identify publications on naturally occurring zoonotic pathogens in equids from nine countries: Austria, the Czech Republic, Germany, Hungary, Italy, Liechtenstein, Slovakia, Slovenia, and Switzerland. We searched three databases-PubMed, Scopus, and CABI-yielding 1,435 publications, of which 256 were included in the review, spanning 58 years of research (1964-2022).

Our findings revealed increased publications on equine-associated zoonotic pathogens in the region since the 1990s, reflecting growing global concerns about zoonoses, with a recent surge in research on emerging zoonotic agents. A total of 191 zoonotic pathogens were investigated during the study period, with the top 10 most studied pathogens representing 60.2% of the included literature. Researchers from 24 countries, organised into nine research communities, collaborated on equine zoonotic diseases in the region. Germany, Italy, the Czech Republic, and the USA played pivotal roles in the research network. Additionally, we reported 183 zoonotic taxa potentially infecting equids and humans in Central Europe, of which 79.2% were bacteria, 15.8% were eukaryotes, and 4.9% were viruses. This expanded list marks a notable increase from the 56 pathogens reported in previous studies. Pairwise comparisons revealed that Italy and Germany shared the highest number of pathogens (40 taxa), followed by Italy and Switzerland (25 taxa), and Germany and Switzerland (25 taxa).

This study offers an updated list of zoonotic pathogens in equids in Central Europe, highlights emerging threats such as West Nile virus, and underscores the importance of continued surveillance and cross-border collaboration to mitigate these risks.