Investigation of parasitic contamination of salad vegetables sold by street vendors in city markets in Damascus, Syria

Abstract

Monitoring parasitic contamination in raw vegetables used in salads is an important measure in controlling the occurrence of gastroenterological diseases, which may be life-threatening. This study aimed to inspect the parasitological contamination of some raw vegetables used in salads. Eight commonly consumed vegetable types were purchased from street vendors in the city markets. Vegetables were washed and the sediments were obtained for microscopic examination. Genomic DNA was isolated from contaminated samples. Our result showed that 34.4% of the studied samples were contaminated with one or more species of parasites. Lettuce was the most commonly contaminated vegetable type (29.5%), while tarragon leaves showed the lowest level of contamination (2.3%). The risk of contamination was significantly higher in lettuce samples in comparison with the other samples studied. Giardia duodenalis was the most prevalent parasite detected (38.6%) and was abundantly found in lettuce isolates (23.5%). Molecular typing revealed that all Giardia samples found in the contaminated specimens belonged to Assemblage B. Blastocystis spp. were the second most prevalent parasite in samples (29.5%), they were frequently detected in lettuce leaves (30.8%). Other parasites were found in low frequencies. The high level of parasitic contamination found in our study indicates an urgent need to identify the sources of contamination and to monitor irrigation water and ensure its cleanliness.

Blastocystis One Health Approach in a Rural Community of Northern Thailand: Prevalence, Subtypes and Novel Transmission Routes

“…Water in the vessels is also used to wash vegetables and tubers hence transfer of cysts of a variety of subtypes could occur this way. Indeed Blastocystis has been previously found in vegetables ( Al Nahhas and Aboualchamat, 2020 ; Li et al, 2020 ). Through fine-scale analysis we identified a case of ST3 in humans overlapping with the subtypes found in their rain collection vessels.…”

The Presence of Potentially Pathogenic Protozoa in Lettuce (Lactuca sativa) Sold in Markets in the Central Peruvian Andes

“…Worldwide, lettuce is one of the most dangerous vegetables because of the presence of pathogens. It was determined that the risk of contamination was 65 times higher in lettuce samples than in tarragon samples and more than 7, 9, and 30 times higher than in spearmint, watercress, and coriander samples, respectively [38]. Therefore, surveillance of parasitic contamination in raw vegetables used in salads, such as lettuce, is a crucial measure to control the occurrence of human gastroenterological diseases [38].…”

Occurrence of Intestinal Parasites of Public Health Significance in Fresh Horticultural Products Sold in Maputo Markets and Supermarkets, Mozambique

“…Blastocysts hominis has been more recently referred as a potentially pathogenic species commonly detected in immunocompromised individuals and associated with a variety of human gastrointestinal disorders [ 47 ]. The appearance of this parasite associated with fresh food was for first reported in Italy in ready-to-eat mixed salads (0.5%) and recently in Syria in lettuce from different markets (30.8%) and in Brazil in lettuce (15%) and coriander (19%) from markets and supermarkets [ 5 , 48 , 49 , 50 ].…”