Human babesiosis in Japan:: Epizootiologic survey of rodent reservoir and isolation of new type of Babesia microti-like parasite
Human babesiosis in Japan:: Epizootiologic survey of rodent reservoir and isolation of new type of Babesia microti-like parasite
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DOI：
10.1128/jcm.39.12.4316-4322.2001
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发表时间：
2001-12-01
影响因子：
9.4
通讯作者：
Ishihara, C
中科院分区：
文献类型：
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作者：
Tsuji, M;Wei, Q;Ishihara, C
我们在日本多个地点进行了动物流行病学调查，以研究该国作为人类巴贝斯虫病病原体宿主的野生动物。在北海道、千叶、滋贺、兵库、岛根和德岛等县的不同地方捕获了6种小型哺乳动物，包括姬鼠（Apodemus speciosus）、黑线姬鼠（Apodemus argenteus）、棕背䶄（Clethrionomys rufocanus）、高山姬鼠（Eothenomys smithii）、臭鼩鼱（Crocidura dsinezumi）和小鼩鼱（Sorex unguiculatus）。在所有6个县都检测到携带类微小巴贝斯虫寄生虫的动物。将它们的血液样本接种到仓鼠体内，共获得20个寄生虫分离株；19个来自姬鼠，另1个来自棕背䶄。对寄生虫小亚基核糖体RNA基因（rDNA）序列进行测序表明，20个分离株中有2个被归类为神户型，因为它们的rDNA与神户株（日本首例病例的菌株）相同。另外18个分离株被归类为一种新型，命名为穗别型，因为它们都具有相同的rDNA序列，该序列与神户型分离株和美国东北部微小巴贝斯虫（美国型）的rDNA序列均有显著差异。具有神户型、穗别型和美国型rDNA的寄生虫在系统发育上彼此密切相关，但在抗原性上明显不同。通过将啮齿动物的分离株接种到红细胞已被人类红细胞替代的严重联合免疫缺陷（SCID）小鼠体内，证明这些分离株对人类红细胞具有感染性。结果表明，一种新型的类微小巴贝斯虫寄生虫，即穗别型，是在日本野生啮齿动物中流行的主要类型，姬鼠是神户型和穗别型类微小巴贝斯虫寄生虫的主要宿主，棕背䶄在北海道岛可能也是一个额外的宿主。
We have carried out epizootiologic surveys at various sites in Japan to investigate wild animals that serve as reservoirs for the agents of human babesiosis in the country. Small mammals comprising six species, Apodemus speciosus, Apodemus argenteus, Clethrionomys rufocanus, Eothenomys smithii, Crocidura dsinezumi, and Sorex unguiculatus, were trapped at various places, including Hokkaido, Chiba, Shiga, Hyogo, Shimane, and Tokushima Prefectures. Animals harboring Babesia microti-like parasites were detected in all six prefectures. Inoculation of their blood samples into hamsters gave rise to a total of 20 parasite isolates; 19 were from A. speciosus, and the other 1 was from C. rufocanus. Sequencing of the parasite small-subunit rRNA gene (rDNA) sequence revealed that 2 of the 20 isolates were classified as Kobe type because their rDNAs were identical to that of the Kobe strain (the strain from the Japanese index case). The other 18 isolates were classified as a new type, designated the Hobetsu type, because they all shared an identical rDNA sequence which differed significantly from both that of Kobe-type isolates and that of northeastern United States B. microti (U.S. type). The parasites with Kobe-, Hobetsu- and U.S.-type rDNAs were phylogenetically closely related to each other but clearly different from each other antigenically. The isolates from rodents were demonstrated to be infective for human erythrocytes by inoculation into SCID mice whose erythrocytes had been replaced with human erythrocytes. The results suggest that a new type of B. microti-like parasite, namely, the Hobetsu type, is the major one which is prevalent among Japanese wild rodents, that A. speciosus serves as a major reservoir for both Kobe- and Hobetsu-type B. microti-like parasites, and that C. rufocanus may also be an additional reservoir on Hokkaido Island.