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Blastocystis is a stramenopile protist of controversial pathogenicity. The organism colonizes a broad range of vertebrate and invertebrate hosts. Blastocystis has also been found in the environment both in water and soil. Several routes of transmission have been proposed including human to human, animal to human, and via contaminated food and water. In recent years, the presence of Blastocystis in vegetables has started to be explored. However, most studies have focused on microscopic detection. Moreover, works of this type from Asia are barely available. Hence, the aim of this preliminary study was to examine the occurrence of Blastocystis in raw vegetables sold in markets in northern Thailand. Fresh produce (n = 20) commonly used in Thai cuisine (Lanna) was purchased from two street markets and screened for Blastocystis using qPCR. Blastocystis was detected in 45% of the samples with the dominant subtype being ST3. Produce growing underground, such as galangal, carrot, and beetroot, were positive for the organism suggesting soil or inadequately composted manure as the source of contamination. To our knowledge, our study is the first to perform subtyping of Blastocystis in vegetables. Our results hint toward fresh produce being a, as yet, not widely explored, transmission route of Blastocystis in the studied community. Looking forward, large-scale investigations on the prevalence of this and other organisms under the One Health umbrella should be undertaken. [ABSTRACT FROM AUTHOR]

Background: Soil-transmitted helminth (STH) infections are major public health problems in poor and developing countries that require fecal contamination of the environment for transmission. The consumption of raw vegetables without proper washing is one of the main routes of intestinal parasite acquisition. Therefore, this study was designed to detect the prevalence of intestinal parasitic contamination in commonly consumed raw vegetables sold in three central open-air markets in Nakhon Si Thammarat province, southern Thailand.Methods: A total of 265 fresh vegetable samples consisting of peppermint, lettuce, coriander, leek, gotu kola, celery, Chinese cabbage, culantro, Thai basil, and Chinese morning glory were purchased from three central open-air markets in the Mueang, Thasala and Sichon districts from December 2016 to March 2017. Each sample was washed with physiological saline, shaken for 15 min, and then allowed to sediment. Finally, sedimentation was performed via the sedimentation concentration technique and examined using light microscopy for the detection of pathogenic parasites.Results: The overall prevalence of parasitic contamination was 35.1% (93/265). The most predominant parasite was hookworms (42.9%), followed by Strongyloides stercoralis (10.6%), Trichuris trichiura (2.6%), Ascaris lumbricoides (2.6%), and Toxocara spp. (2.6%). The highest level of contamination was found in celery, with a prevalence rate of 63.3% (19/30), while the lowest contamination level was found in Chinese morning glory, with a prevalence rate of 2.0% (2/30). The prevalence of intestinal parasite contamination in Mueang district (51.5%) was significantly higher than that in Thasala district (17.9%) and Sichon district (30.6%) (P < 0.001).Conclusion: The results of the present study demonstrate that consumption of vegetables with parasite contamination in this area represents a potential route for the transmission of parasitic infection, particularly hookworm infection. Therefore, it is necessary for health authorities to educate consumers about the proper washing of vegetables prior to consumption. Preventive methods such as wearing gloves and washing hands after handling vegetables should also be advocated to sellers who are at risk of acquiring STH infections via skin penetration. [ABSTRACT FROM AUTHOR]