関東地方利根川水系における慢性日本住血吸虫症とそのスクリーニング法 Chronic Schistosomiasis Japonica Cases in the Tone River Basin, Honshu, and its Early Diagnosis

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Abstract

関東地方利根川流域で感染した慢性日本住血吸虫症について, 茨城県内診断例12例を中心に, その診断法・病態・治療適応について検討した. 患者は, すべて海外渡航歴・利根川以外の本症流行地への旅行歴はなく, 取手市戸頭, 稲敷郡河内村, 筑波郡谷和原村等かつて本症の流行が報じられた地域の在住者である. 血中抗住血吸虫抗体及び糞便中の虫卵は検査したすべての症例で陰性であった. 8例の患者の確定診断は, 本症とは異なる基礎疾患で摘出された臓器 (胃・十二指腸等上部消化管及び肝・胆道系) 中の日本住血吸虫虫卵の病理学的検索によってなされた. しかし, 茨城県取手市戸頭の3症例と筑波郡伊奈町の1症例は, 人間ドックで画像診断学的に診断されており, 流行地における本症患者のスクリーニングには, 肝エコーにおける魚鱗状パターン, 肝CT像における被膜石灰化像・隔壁様石灰化像等特徴的所見も有用であることが示された. また, その病態は, 基礎疾患によって異なっており, 胃癌・肝癌等悪性腫瘍との合併例は4例であった. プラジカンテルによる治療適応の判定には, 虫卵排出の有無及び虫卵の孵化能の検索が必要であるが, 疑わしい症例には生検材料による孵化試験をすることが必要である. 病理組織学的検索だけでは, 感染時期及び孵化能の判定は困難である.

Twelve cases of chronic schistosomiasis japonica associated with other diseases were studied. All the patients have lived for a long time in an old endemic area of schistosomiasis in Ibaraki Prefecture, Honshu, and have never been overseas nor in other schistosomiasis areas in Japan. In the 8 cases shistosome eggs were found in the ectomized organs (stomach, duodenum, liver and gall bladder) surgically operated under another diagnosis. The remaining 4 cases were diagnosed radiologically at the time of their medical checkups. Specific findings in these cases, fish scale pattern of liver ultrasonography and furnicular calcification and high density streak in liver C.T. may be of great value as an early diagnostic procedure of chronic schistosomiasis. No schistosome eggs were found in the 12 stool specimens. The 6 of the 12 sera were tested for S. Japonicum egg antibodies and all were found to be negative. Symptoms and signs were much different in each patient depending on the basal diseases. There were 4 cases complicated with malignant tumors like gastric cancer or hepatoma. It is very difficult to judge the time they became infected and the hatchability of the eggs can be noted only by the pathological findings. The hatching tests of eggs in the rectal biopsy specimens may be done to observe their viability.

Journal

  • Kansenshogaku Zasshi

    Kansenshogaku Zasshi 62(2), 156-163, 1988

    The Japanese Association for Infectious Diseases

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