Detection of Gastrointestinal Pathogens with Zoonotic Potential in Horses Used in Free-Riding Activities during a Countrywide Study in Greece

Abstract

The objectives of this study were (a) to detect zoonotic gastrointestinal pathogens in faecal samples of horses using the FilmArray^® GI Panel and (b) to identify variables potentially associated with their presence. Faecal samples collected from 224 horses obtained during a countrywide study in Greece were tested by means of the BioFire^® FilmArray^® Gastrointestinal (GI) Panel, which uses multiplex-PCR technology for the detection of 22 pathogens. Gastrointestinal pathogens were detected in the faecal samples obtained from 97 horses (43.3%). Zoonotic pathogens were detected more frequently in samples from horses in courtyard housing (56.0%) than in samples from horses in other housing types (39.7%) (p = 0.040). The most frequently detected zoonotic pathogens were enteropathogenic Escherichia coli (19.2% of horses) and Shiga-like toxin-producing E. coli stx1/stx2 (13.8%). During multivariable analysis, two variables emerged as significant predictors for the outcome 'detection of at least one zoonotic pathogen in the faecal sample from an animal': (a) the decreasing age of horses (p = 0.0001) and (b) the presence of livestock at the same premises as the horses (p = 0.013). As a significant predictor for the outcome 'detection of two zoonotic pathogens concurrently in the faecal sample from an animal', only the season of sampling of animals (autumn) emerged as significant in the multivariable analysis (p = 0.049). The results indicated a diversity of gastrointestinal pathogens with zoonotic potential in horses and provided evidence for predictors for the infections; also, they can serve to inform horse owners and handlers regarding the possible risk of transmission of pathogens with zoonotic potential. In addition, our findings highlight the importance of continuous surveillance for zoonotic pathogens in domestic animals.

Keywords: Campylobacter; Cryptosporidium; Escherichia coli; FilmArray; Giardia; Norovirus; Salmonella; Vibrio; Yersinia; diarrhoea; donkey; horse; zoonotic infection.

Figure 1

Location of horses (n = 224) from which faecal samples were collected in Greece.

Figure 2

Proportion of faecal samples from horses (n = 224) in Greece, in which zoonotic gastrointestinal pathogens were detected, in accordance with the type of horse housing. Grey bars: proportions of horses in which pathogens were detected; green bars: proportions of horses in which pathogens were not detected.

Figure 3

Seasonal change in the detection rate of zoonotic gastrointestinal pathogens in faecal samples from horses (n = 224) in Greece. The dashed line is the trendline.

Figure 4

Box and whisker plot of the age of horses (n = 224) in Greece, in accordance with the detection of zoonotic gastrointestinal pathogens in faecal samples and the presence of livestock at the same premises. Green bars: horses in which pathogens were not detected; grey bars: horses in which pathogens were detected; motif pattern: no presence of livestock at same premises; full pattern: presence of livestock at same premises.

Figure 5

Biplot of results of principal component analysis for detection of zoonotic gastrointestinal pathogens in faecal samples from horses in Greece, in accordance with season when sampling took place, location of horse (part of the country), age of horse, and presence of livestock at the same premises. Grey dots: horses in which pathogens were detected; green dots: horses in which pathogens were not detected.

Figure 6

Seasonal change in the detection rate of two zoonotic gastrointestinal pathogens concurrently in faecal samples from horses (n = 224) in Greece. The dashed line is the trendline.