Abstract
The prevalence of soil-transmitted parasitic diseases such as ascariasis and hookworm disease, which were once predominant in Japan, drastically declined from 1945 to 1970 due to various efforts, including improvement in domestic hygiene, school education, and the use of chemical fertilizers. According to food poisoning statistics from 1963 to 1997, Vibrio parahaemolyticus food poisoning was mainly caused by the consumption of fish and its processed products and was the largest cause of food poisoning in Japan, accounting for an average of 30%. However, with improvements in cold chain technology and the introduction of the Food Sanitation Act, the food standards in terms of V. parahaemolyticus contamination have improved, and it now accounts for <1% of food poisoning occurrences. In contrast, with the expansion of the cold chain network in Japan, increased incidences of parasitic diseases caused by seafood consumption have been reported.
In 1997, the Food Poisoning Surveillance Subcommittee of the Ministry of Health and Welfare warned of 14 parasitic diseases in three categories: (1) The parasitic diseases that frequently occur nationwide; (2) the parasitic diseases that frequently occur overseas and will be of concern in the future; and (3) the parasitic diseases that are infrequent but pose severe health hazards from infection. In 1999, an amendment to the food poisoning statistics creation guidelines pertaining to the Food Sanitation Act was proposed, resulting in parasitic food and drink health hazards being considered as food poisoning and thus being subjected to notification/investigation. Subsequently, in 2011, Kudoa septempunctata, a kudoid parasite (Myxozoa: Multivalvulida) in flounder, and Sarcocystis fayeri in horses have recently been designated as etiologic agents of food poisoning. K. septempunctata, S. fayeri, anisakid larvae, and other parasites were listed as distinct food poisoning agents in the manual of food poisoning statistics, requiring doctors to report cases to a public health center. Consequently, it is become possible to evaluate the actual state of foodborne parasitic diseases in Japan.
Of the 16 food-borne parasitic diseases caused by the above mentioned parasites, this article reviews 7 diseases caused by raw fish consumption such as food poisoning from K. septempunctata, which has been a recent problem; food poisoning from Anisakis larvae, which has an increasing number of reported cases; diphyllobothriasis caused by salmon consumption, which has been reported in many infectious cases; and the sporadic parasitic diseases of larval spiruriniasis, paragonimiasis, meagonimiasis, and diplogonoporiasis.
