Paddy field dermatitis in Kagoshima Prefecture / 日本農村医学会雑誌

ABSTRACT

A dermatitis of unknowns etiology has occurred among the farmers working in paddy fields in some districts of Kagoshima Prefecture, such as Ibusuki, Hiyoshi, Oura, Makizono and Minami-tane.<BR>In order to acertain the cause of the disease, the epidemiological investigations have been made since1975.<BR>The dermatitis occurrs from March to July when rice-planting and weeding are on and is characterized by erythemato- papulo-vesicular eruptions accompanied with severe itching. The chief symptoms are observed on the parts exposed to water, especially on forearms and lower legs.<BR>The research for snail intermediate hosts was carried out in the paddy fields where the dermatitis originated.<BR>As a result, two species of apharyngeal furcocercous cercariae were obtained from the fresh water snails, <I>Polypylis hemisphaerula</I> and <I>Austropeplea ollula</I>. The cercaria from <I>P. hemisphaerula</I> resembled to that of<I> Gigantobilharzia sturniae</I> in shape and size, and the other one from <I>A. ollula</I> was identified as species belonging to the genus Trichobilharzia and was regarded the same species as described in Saitama Prefecture by the authors.<BR>An experimental infection with the cercaria belonging to the genus <I>Trichobilharzia</I> was performed. A few drops of water containing10cercariae were placed on the forearm. The cercariae invaded into the skin and produced a dermatitis quite similar to that prevailing in the endemic areas.<BR>Therefore, it was concluded that the etiological agent were the cercariae of two different avian schistosomes, namely, <I>G. sturniae</I> and <I>Trichobilharzia</I> sp.