Prevalence of Salmonella, Cryptosporidium and Leptospira in Invasive Pond Slider (Trachemys scripta) in North-Western Italy

Abstract

Natural lakes and ponds typically feature green areas where people engage in recreational and sporting activities. In Italy, these areas are often inhabited by non-native freshwater turtles, even at high densities. However, freshwater turtles have been identified as natural carriers for various pathogens that can be transmitted to humans, making their sanitary monitoring crucial to prevent accidental transmission through direct or indirect contact. In this study, we investigated the presence of three potentially zoonotic pathogens, namely Salmonella, Leptospira and Cryptosporidium, in a group of 83 freshwater turtles (Trachemys scripta) captured in Piedmont, Northwest Italy. Overall infection prevalence was 9.6%. Salmonella spp. was detected in ten specimens of T. s. elegans and Cryptosporidium ducismarci in one specimen of T. s. scripta. Salmonella enterica subsp. diarizonae was confirmed in ten freshwater turtles. No Leptospira DNA was detected. Our findings highlight that turtles, as asymptomatic carriers of zoonotic pathogens, contribute to environmental contamination and public health risks, underscoring the need for sanitary monitoring of invasive alien species under a 'One Health' approach.

Keywords: alien species; apicomplexan; pathogen; protozoan; reptile; zoonosis.

FIGURE 1

Map of location site: (a) Italy with the Piedmont region in yellow; (b) Avigliana Lakes (Lago Grande and Lago Piccolo), with the capture area in yellow.