PHWR Public Health Weekly Report

According to the 8^th Nationwide Survey for Intestinal Parasites in 2012, the intestinal parasitic infection rate in Korea was 2.6% of the population. Fish-borne parasites, such as Clonorchis sinensis , remain a main source of intestinal parasitic infection. So far, Korea Disease Control and Prevention Agency (KDCA) has been promoting a project to decrease fish-borne parasitic infections, mainly in endemic areas. The aim of this article was to analyze the results of the infection status of intestinal parasites and the degree of infection risk for residents where freshwater fish, an intermediate host, are predominant. The focus was on areas with high foodborne parasite infections such as liver flukes. The project was carried out in 2020 and the methodology consisted of microscopic examination of 11 intestinal parasites through the cooperative system of KDCA-local government-KAHP (Korea Association of Health Promotion). The infection rates of intestinal parasites increased from 5.0% in 2019 to 5.9% in 2020. As for the type of parasite, the infection rate of Clonorchis sinensis was the highest at 3.8%, followed by heterophyids (1.7%), Trichuris trichiura (0.2%), and Gymnophalloides seoi (0.1%). Among the total survey areas, the infection rates of 3 new participating areas were 24.5%, 10.8%, and 7.9%, respectively; significantly exceeding the overall average infection rate of 3.8%. The metacercaria of C. sinensis were all detected in 11 survey areas, and the main infected fish species were Pungtungia herzi, Pseudorasbora parva, and Squalidus spp. In the endemic area of intestinal parasites, the infection rate of fish-borne trematodes such as C. sinensis and heterophydis were consistent. Therefore, this article recommended a series of steps to reduce the infection rate until the level of elimination is reached, and suggested that progress in the investigation areas be actively monitored.

Key words Intestinal parasites, Clonorchis sinensis, Liver flukes, Freshwater fish, Infection rate, Risk of infection, Foodborne trematodes

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