Valtonen E T, Haaparanta A, Hoffmann R W
Department of Biology, University of Jyväskylä, Finland.
Int J Parasitol. 1994 Apr;24(2):197-206. doi: 10.1016/0020-7519(94)90026-4.
Seasonality and size-related infection of Raphidascaris acus larvae from the inner organs and intestine of roach (Rutilus rutilus) were studied in 4 lakes of differing water quality and pollution level in Central Finland between August 1985 and November 1986. The influence of R. acus larvae on the liver and pancreatic tissues of roach was examined histologically in additional material from 1989 and 1990. The inner organs of roach were most heavily infected with R. acus in the eutrophic, polluted Lake Vatia (63% of fish infected with 4.0 nematodes/fish) and in the two eutrophic lakes, compared to the oligotrophic Lake Peurunka (23%, 0.8). The prevalence of free R. acus larvae in the intestine of roach was almost as high but the intensity only about half of that found in the inner organs. The prevalence of infection had significantly higher values in autumn in most cases, and larvae accumulated in the inner organs and intestine of older roach. In histological studies it was found that larvae occurred more often in the pancreatic tissue than in the liver, but in both organs the majority of the larvae were dead and partly destroyed. The most typical host response against R. acus was a chronic granulomatous inflammatory reaction. Granulomas and developing granulomas containing worms at different stages of degeneration are described; they were found in all of the lakes studied throughout the year and also in one and the same fish. On average only 37 and 21% of the worms in the liver and pancreas, respectively, were alive. No obvious difference in the histological response against R. acus was noted between the lakes.
1985年8月至1986年11月期间，在芬兰中部4个水质和污染程度不同的湖泊中，研究了拟丽突线虫幼虫在拟鲤（Rutilus rutilus）内脏和肠道中的季节性感染及与鱼体大小的关系。1989年和1990年，利用补充材料对拟丽突线虫幼虫对拟鲤肝脏和胰腺组织的影响进行了组织学检查。与贫营养的佩伦卡湖（23%，每条鱼感染0.8条线虫）相比，富营养化且受污染的瓦提亚湖（63%的鱼感染，每条鱼感染4.0条线虫）以及另外两个富营养化湖泊中，拟鲤的内脏受拟丽突线虫感染最为严重。拟鲤肠道中游离的拟丽突线虫幼虫感染率几乎相同，但感染强度仅为内脏中发现的一半左右。在大多数情况下，秋季的感染率明显更高，幼虫在年龄较大的拟鲤内脏和肠道中积累。组织学研究发现，幼虫在胰腺组织中出现的频率高于肝脏，但在这两个器官中，大多数幼虫已经死亡并部分被破坏。对拟丽突线虫最典型的宿主反应是慢性肉芽肿性炎症反应。描述了含有处于不同退化阶段蠕虫的肉芽肿和正在形成的肉芽肿；全年在所有研究的湖泊中以及同一条鱼中都发现了它们。平均而言，肝脏和胰腺中分别只有37%和21%的蠕虫存活。各湖泊之间在对拟丽突线虫的组织学反应上没有明显差异。
