Molecular detection of Cyclospora in water, soil, vegetables and humans in southern Italy signals a need for improved monitoring by health authorities

Abstract

To date, in Europe, there is scant information on the occurrence of Cyclospora in water from treatment plants and in humans, and no data are available on soil or fresh plant products. Here, we undertook the first molecular survey of Cyclospora in multiple biological matrices collected from the Apulia region of southern Italy. Samples of irrigation water from four municipal treatment plants, eight different types of vegetables or fruit (cucumber, lettuce, fennel, celery, tomato, melon, endive and chicory) and soil from the same farms on which these plants were grown, as well as faecal samples from humans living in the same region were tested by qPCR-coupled single-strand conformation polymorphism (SSCP) analysis and DNA sequencing. Cyclospora was detected in 15.5% of all 213 samples tested. Specifically, this protist was detected in (i) treated water (21.3% of 94 samples), well water (6.2% of 16), but not drinking water (0% of 3); (ii) soil (11.8% of 51 samples) and vegetables (12.2% of 49), with the highest prevalence (18.7%) on fennel; and (iii) human stools (27.5% of 40 samples). In environmental and food samples, Cyclospora was detected mainly in autumn and was significantly more prevalent in the faeces from humans of 40-50 years of age. This is the first comprehensive molecular survey of Cyclospora in environmental, food and human faecal samples in Europe. These data suggest that irrigation water, soil and vegetables might be contaminated by Cyclospora cayetanensis, which might represent a source of infection to humans in the study area and calls for monitoring by health authorities.

Keywords: Cyclospora cayetanensis; Food safety; Human; SSCP; Soil; Vegetable; Water; qPCR.