Christensen C M, Barnes E H, Nansen P
Danish Centre for Experimental Parasitology, Royal Veterinary and Agricultural University, Frederiksberg C., Copenhagen, Denmark.
Parasitology. 1997 Nov;115 ( Pt 5):545-52. doi: 10.1017/s0031182097001571.
A trickle infection experiment was undertaken to study in detail the population dynamics of Oesophagostomum dentatum in pigs. Three groups of 32 pigs were inoculated via the feed twice weekly with 100 (Group A), 1000 (Group B) or 10,000 (Group C) O. dentatum infective larvae (L3). Five pigs from each group were killed 2, 4, 8, 12, 16, and 20 weeks after the first inoculation (p.i.) to determine their worm burdens. Weekly faecal egg counts were determined. At slaughter, worms were counted, differentiated according to sex and developmental stage, and their length measured. Faecal egg counts ranked with dose rate until week 15, but later were more variable. The proportion of the total number of L3 administered which were recovered at slaughter inversely ranked with dose rate. In group C it decreased over time, whereas in groups A and B there was no consistent pattern. Worm fecundities (epg/female) in groups A and B were higher than in group C. The lengths of the female worms increased over time, whereas the lengths of the male worms remained approximately constant from week 8. The study suggests reduced establishment of incoming larvae and lower fecundity of the female worms at high dose levels.
进行了一项微量感染实验，以详细研究猪齿状食道口线虫的种群动态。将三组32头猪每周两次通过饲料接种100条（A组）、1000条（B组）或10000条（C组）齿状食道口线虫感染性幼虫（L3）。在首次接种后2、4、8、12、16和20周，每组宰杀5头猪以确定其虫负荷。每周测定粪便虫卵计数。屠宰时，对蠕虫进行计数，根据性别和发育阶段进行区分，并测量其长度。粪便虫卵计数在第15周之前与剂量率呈正相关，但之后变化更大。屠宰时回收的L3总数占给药L3总数的比例与剂量率呈负相关。在C组中，该比例随时间下降，而在A组和B组中则没有一致的模式。A组和B组的蠕虫繁殖力（每雌虫epg）高于C组。雌虫的长度随时间增加，而雄虫的长度从第8周起大致保持不变。该研究表明，在高剂量水平下，进入的幼虫定植减少，雌虫繁殖力降低。
