Deliverable JRP18-WP3-T6-Contamination of vegetables for human consumption by Em/Eg

A total of 1,120 lettuce samples but also 69 from other vegetables (mainly parsley, spinach and chard) were collected during the summers 2020-2021 from local markets, producers, kitchen gardens and supermarkets with around 50-100 samples collected by each partner which realized the first washing step of the filtration method. The sequential sieving and molecular detection were realized at the Anses to assure homogenous assays and the correct limit of detection which was estimated at 3 eggs in 95% of the cases and 2 and 1 eggs in 75% and 50% of the cases, respectively. When possible pools of two lettuces from the same origin were realized. Considering Em endemic areas, the proportion of Em positive lettuce samples was 1.1%, while it was 2.1% for Eg sl considering all areas (Table X). Additionally, other Taenidae species were detected in 2.4% of the samples mainly Hydatigera sp. and T. hydatigena.

A second mutlicentre on the detection of Echinococcus spp. eggs in berries was realized mainly concerning strawberries and blueberries. The filtration method was validated on strawberries with 95% probability of detection of 3 eggs in 200g sample (88% for both 1 and 2 eggs). In 2022, 12 partners (including external partners Finland and Tunisia) have collected 20 to 30 samples per country trying to prioritize local markets and completed by supermarkets if needed. In total, 412 berries samples were collected. Em was detected in 12 cases (6.9%) in strawberries and 6 cases (7.8%) in blueberries from all known endemic countries excepting Poland with higher proportions for the two Baltic countries. Eg ss was detected in 1.3% of strawberries and 1% of blueberries for European countries with very high proportion of 81.3% in strawberries from Tunisia. No case of Em and Eg sl were obtained from the others types of berries. In Europe, the proportions of contaminations in strawberries and blueberries is similar for Em and for Eg sl but seems more important for Em comparing to lettuces.  Others cestode species were detected in six cases.

This are the two largest epidemiological study ever conducted on contamination of vegetables and berries by Em and Eg which will contribute to the understanding of foodborne transmission.