MEDICAL GEOGRAPHICAL STUDY ON SCHISTOSOMIASIS JAPONICA
MEDICAL GEOGRAPHICAL STUDY ON SCHISTOSOMIASIS JAPONICA
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日本血吸虫病医学地理研究
DOI：
10.4157/grj.45.391
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发表时间：
1972
期刊：
影响因子：
--
通讯作者：
S. Asami
中科院分区：
文献类型：
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作者：
N. Nihei;S. Asami
日本血吸虫病是东亚和东南亚地区著名的地方病之一。已成为影响疫区社会经济发展的阻碍因素。因此，从医学地理学的角度来看，这种疾病可以作为区域研究的课题。在这篇论文中，作者指出，作为他们研究的第一步，这种疾病非常普遍，并研究了控制其分布的一些因素。该病是由人类、中间宿主（一种名为Oncornclania hupcnsis nosophora的螺类）和日本血吸虫三种因素共同作用引起的病理复合体。根据经验众所周知，其中最重要的因素是蜗牛。考虑到迄今报道的论文所揭示的蜗牛生态特征与每个流行地区的环境条件之间的关系，作者调查了地形和土壤作为限制该疾病分布的控制因素。结果如下： 一、该病的分布仅限于日本四、五个地区。二.参照洪泛区地貌分类，栖息地地貌分为以下三类。它们是： (1) 下三角洲平原；由淤泥和粘土等细粒物质形成的低地，洪水长期滞留在其上。主要流行地区属于这一类型，即筑后河中部流域、神锅流域以及利根河和荒川河流域的大部分地区。 (2) 下冲积扇；大雨可能会淹没土地，但雨后水很快就会流失。筑后川流域的一部分和甲府流域的大部分都属于这种类型。 (3) 上部冲积扇；地表坡度较陡，排水良好，近期从未经历过洪水。这种类型被认为是一种不寻常的情况。甲府盆地米代河形成的扇子的一部分是唯一的例子。因此，简而言之，除了少数例外，流行区的许多陆地表面都属于第一类型。或者说，通过洪水类型的地貌划分图可以很好地解释该病流行区的分布格局。然而，日本最大和最明显的流行地区甲府盆地被列为第二或第三类，这表明仅靠洪水地形可能无法解释该疾病的分布。三．通过对钉螺分布不均的流行区各个地形单元的详细观察，发现影响这种微土地条件的一个重要因素可能是土壤。然而，之前有关该病的报道并未显示有关流行地区土壤的准确数据。笔者尝试在实验室培育蜗牛，以期明确影响蜗牛栖息的土壤特性。用于调查的土壤样本是在许多地方采集的；不仅在甲府盆地，在关东、中部地区的其他平原和盆地也是如此。其中包含具有特殊质地的人工混合土壤材料。实验项目为：粒度分离（ASK法）、土壤质地测量、腐殖质含量测定（Tiurin法）以及土壤母质差异研究。研究结果如下：（1）各地样本的初孵钉螺数量、幼钉生长速度和成活率存在显着差异。特别是在 KOf u 栖息地采集的样本显示最适合蜗牛生活。
Schistosomiasis japonica is one of the famous endemic disease found in east and southeast Asia. It has been a preventing factor against the social and economical development in the endemic areas. From the above reason this disease can be taken up as a subject of regional study from the view point of medical geography. In this paper the writers pointed out, as the first step of their study, a remarkable ubiquity of this disease, and examined some factors controlling its distribution. This disease is caused by a pathological complex of three factors-human being, intermediate host (a species of snail named Oncornclania hupcnsis nosophora) and Schistosorna japonicum. It is empirically well known that the most important factor among them is the snail. Taking into account the relation between ecological characters of the snail revealed by papers hitherto reported, and environmental conditions in each endemic area, the writers investigated the topography and soil as controlling factors delimiting the distribution of the disease. The results are as follows: I. The distribution of the disease is limited only to four or five localities in Japan. II. Landf orms of the habitats are classified into following three types, with reference to the landform classification of flood areas. They are: (1) Lower deltaic plain; lowlands formed by fine materials such as silt and clay, on which flood water stands deeply for a long period. To this type belong the main endemic areas, i.e. a greater part of the middle basin of the River Chikugo, the Kannabe basin, and basins of the River Tone and the River Arakawa. (2) Lower alluvial fan ; lands which may be flooded by heavy rain, but the water drains soon after the rain. A part of the basin of the River Chikugo and a greater part of the Kofu basin are classified as this type. (3) Upper alluvial fan; the surface slope is relatively steep and is well drained, having never experienced recent flood. This type is thought to be of an unusual case. A part of the fan formed by the River Midai in the Kofu basin is the only example. Thus, in brief, many of the land surfaces of the endemic areas are of the first type, with only a few exceptions. Or, in other word, the distribution pattern of the endemic areas of this disease can be well explained through landform division map by flood-type. However, the largest and the most marked endemic area of Japan, the Kofu basin, is classified as the second or the third type, suggesting that the flood topography alone may not explain the dis tribution of the disease. III. By observing in detail each topographic unit of the endemic areas where the snail inhabits are maldistributed, it was found that an important factor affecting such micro land conditions might be the soil. However no precise data concerning the soil of the endemic areas has been shown by the previous reports on this disease. The writers tried to breed snails in the laboratory for the purpose of clarifying soil characters which have influence upon the inhabitation of the snail. Soil samples used for the investigation were collected in many localities ; not only in the Kofu basin but in other plains and basins of Kanto and Chubu districts. In them were included artificially mixed soil materials with special texture. Experimental items were: separation of particle-size (by ASK method), measurement of soil texture, determination of humus contents (by Tiurin method) and investigation of differences caused by soil parent materials. The results obtained are as follows: (1) Remarkable differences in the numbers of newly hatched snails and in speed of growth and survival rates of youngs were found among samples from, each locality. Especially a sample collected in KOf u habitats showed to be the most suitable for the snail life.