Sovell J R, Holmes J C
Department of Zoology, University of Alberta, Edmonton, Canada.
J Wildl Dis. 1996 Jan;32(1):23-30. doi: 10.7589/0090-3558-32.1.23.
From July 1990 to February 1991, nematode numbers in free-ranging snowshoe hares (Lepus americanus) at Kluane Lake, southwestern Yukon, Canada, were manipulated by subcutaneous injection (0.4 mg/kg) of ivermectin. Three field experiments were conducted to determine the degree of helminth loss associated with a single administration of ivermectin; the length of time that ivermectin was effective in reducing worm numbers; and the effect of repeated ivermectin administration in reducing worm numbers. Numbers of the nematodes, Protostrongylus boughtoni and Nematodirus triangularis were reduced by approximately 80% 2 wk after treatment with a single dose of ivermectin, and were still significantly lower than controls at 4 wk. However, beyond 2 wk, ivermectin did not affect the rate of acquisition of new worms of either species. All treated groups contained one or more hares in which numbers of P. boughtoni and N. triangularis were not reduced. In addition, ivermectin had no effect on numbers of Trichuris leporis or Passalurus sp. Overall, ivermectin was not as effective against the nematodes of free-ranging hares as has been reported for nematodes of domestic and laboratory animals.
1990年7月至1991年2月，在加拿大育空地区西南部的克卢恩湖，对自由放养的雪兔（美洲兔）体内的线虫数量进行了控制，方法是皮下注射伊维菌素（0.4毫克/千克）。进行了三项野外实验，以确定单次施用伊维菌素后蠕虫减少的程度；伊维菌素减少蠕虫数量有效的时长；以及重复施用伊维菌素对减少蠕虫数量的影响。用单剂量伊维菌素治疗2周后，原圆线虫和三角细颈线虫的数量减少了约80%，在4周时仍显著低于对照组水平。然而，在2周之后，伊维菌素对这两种线虫新虫的感染率没有影响。所有处理组都包含一只或多只雪兔，其体内的原圆线虫和三角细颈线虫数量未减少。此外，伊维菌素对兔鞭虫或兔艾美尔球虫的数量没有影响。总体而言，伊维菌素对自由放养雪兔体内线虫的效果不如对家养动物和实验动物体内线虫的效果显著。
