Forrester S G, Lankester M W
Department of Biology, Lakehead University, Thunder Bay, Ontario, Canada.
J Wildl Dis. 1997 Jul;33(3):511-6. doi: 10.7589/0090-3558-33.3.511.
A major weakness of the Baermann funnel technique for extracting nematode larvae from feces is the funnel. As many as 67% of Parelaphostrongylus tenuis first-stage larvae lodged on the sloping surface of glass Baermann funnels. The number of larvae collected after 24 hr was not significantly correlated with total numbers in the samples, whether feces were supported over tissue paper or over window screening. Instead, we collected about 8 times as many larvae and achieved a significant relationship between larvae collected and the total numbers present when pelleted fecal material was submerged over screening in vertical-sided beakers. The methodology of this more efficient and more accurate way of estimating numbers of protostrongylid larvae is described. Most larvae were located on and in the mucous layer covering fecal pellets and readily left fresh pellets emersed in water; 72% of these larvae left after 6 min and only 11% remained after 1 hr. Larvae in water at room temperature sank as fast as 6 cm/min, but those close to a vertical glass surface sank more slowly (97% sank 18.5 cm in 105 min).
用于从粪便中提取线虫幼虫的贝尔曼漏斗技术的一个主要缺点在于漏斗。多达67%的细颈帕拉线虫第一阶段幼虫附着在玻璃贝尔曼漏斗的倾斜表面上。无论粪便放置在薄棉纸还是窗纱之上，24小时后收集到的幼虫数量与样本中的总数均无显著相关性。相反，当将粪便颗粒浸没在垂直壁烧杯中的窗纱上时，我们收集到的幼虫数量约为原来的8倍，且收集到的幼虫数量与样本中实际存在的总数之间存在显著相关性。本文描述了这种更高效、更准确地估计原圆线虫幼虫数量的方法。大多数幼虫位于覆盖粪便颗粒的黏液层上或其中，并且很容易离开浸在水中的新鲜粪便颗粒；其中72%的幼虫在6分钟后离开，1小时后仅11%的幼虫仍留在粪便颗粒上。室温下水中的幼虫下沉速度可达6厘米/分钟，但靠近垂直玻璃表面的幼虫下沉速度较慢（97%的幼虫在105分钟内下沉18.5厘米）。
