Current High Prevalence of Intestinal Parasitic Contamination in Fresh Vegetables in Northeast Thailand

Although fresh vegetables are a vital source of essential nutrients and dietary fiber, they can pose a significant health risk due to contamination by intestinal parasites (IPs). The consumption of contaminated vegetables can lead to intestinal parasitic infection, which is a major public health issue, particularly in tropical and subtropical regions, where sanitation, clean water, and agricultural practices are often inadequate. Northeast Thailand, with its warm, humid climate and predominant agricultural sector, exhibits a high prevalence of IPs in humans. This study aimed to determine the prevalence of intestinal parasitic contamination in vegetables in Khon Kaen, Thailand, because of its reported high prevalence of IPs. A total of 300 samples, including cilantro, celery, Thai basil, lettuce, cucumber, Chinese kale, white cabbage, Chinese cabbage, peppermint, and yard-long beans, were collected from 10 markets across five districts in the province. Each sample was washed with 1% normal saline, shaken for 15 minutes, and allowed to sediment. The sediment was then centrifuged and examined by parasitologists under a microscope. The overall prevalence of IPs was found to be 36.0%, with Blastocystis hominis (24.7%), Strongyloides stercoralis (13.0%), and Ascaris lumbricoides (8.7%) being the most common. Peppermint showed the highest prevalence rate at 70.0%, followed by celery and Thai basil at 53.3% each. These results suggest a necessity for key health policy interventions, including appropriate health education. Sanitary measures, such as washing vegetables before consumption and washing hands after harvesting vegetables, should be encouraged among farmers, sellers, and consumers.