Department of Parasitology, Kurume University School of Medicine, Kurume, Japan.
Department of Parasitology, National Institute of Infectious Diseases, Shinjuku-ku, Japan.
Neuropathology. 2019 Aug;39(4):251-258. doi: 10.1111/neup.12582. Epub 2019 Jun 26.
Over 600 cases of amoebic encephalitis caused by pathogenic free-living amoebas (Balamuthia mandrillaris, Acanthamoeba spp., and Naegleria fowleri) have been reported worldwide, and in Japan, 24 cases have been reported from the first case in 1976 up to 2018. Among these cases, 18 were caused by B. mandrillaris, four by Acanthamoeba spp., one by N. fowleri, and one was of unknown etiology. Additionally, eight cases were diagnosed with encephalitis due to pathogenic free-living amoebas before death, but only three cases were successfully treated. Unfortunately, all other cases were diagnosed by autopsy. These facts indicate that an adequate diagnosis is difficult, because encephalitis due to pathogenic free-living amoebas does not show typical symptoms or laboratory findings. Moreover, because the number of cases is limited, other cases might have been missed outside of those diagnosed by autopsy. Cases of encephalitis caused by B. mandrillaris have been reported from all over Japan, with B. mandrillaris recently isolated from soil in Aomori prefecture. Therefore, encephalitis caused by pathogenic free-living amoebas should be added to the differential diagnosis of encephalitis patients.
全世界已有超过 600 例由致病性自由生活阿米巴（棘阿米巴属、棘阿米巴属和福氏耐格里虫）引起的脑脓肿病例报告，在日本，自 1976 年首例病例报告至 2018 年，共报告了 24 例。在这些病例中，18 例由曼氏棘阿米巴引起，4 例由棘阿米巴属引起，1 例由福氏耐格里虫引起，1 例病因不明。此外，在死亡前有 8 例被诊断为致病性自由生活阿米巴引起的脑炎，但只有 3 例成功治疗。不幸的是，所有其他病例都是通过尸检诊断的。这些事实表明，充分的诊断是困难的，因为致病性自由生活阿米巴引起的脑炎没有典型的症状或实验室发现。此外，由于病例数量有限，其他病例可能在尸检诊断之外被遗漏。在日本各地都有曼氏棘阿米巴引起的脑炎病例报告，最近在青森县的土壤中分离出了曼氏棘阿米巴。因此，致病性自由生活阿米巴引起的脑炎应纳入脑炎患者的鉴别诊断。
