Slomke A M, Lankester M W, Peterson W J
Department of Biology, Lakehead University, Thunder Bay, Ontario, Canada.
J Wildl Dis. 1995 Apr;31(2):125-35. doi: 10.7589/0090-3558-31.2.125.
The prevalence and intensity of Parelaphostrongylus tenuis was determined by examining the head and a fecal sample from each of 379 white-tailed deer (Odocoileus virginianus) of known age that had been killed by vehicles in northeastern Minnesota (USA), November 1991 to May 1993. Small numbers of adult worms (mean +/- SD, 3.2 +/- 2.2; maximum, 13) were found in the cranium of 311 (82%); but over a third (118 of 311) of the infected deer were not passing larvae in their feces. Most occult infections were sterile because only one sex of the parasite was present. Adult P. tenuis were not found in the vertebral canal of deer. Prevalence of adult worms and larvae was lower in fawns (68% and 35%, respectively) than in older age classes of deer (89% and 63%, respectively). Forty-three of 45 deer between 7 and 15 yr old were infected. Mean (+/- SD) intensity of adult worms was lower in fawns (2.7 +/- 1.8) and yearlings (3.0 +/- 2.1) than in deer 7 to 15 yr (4.1 +/- 2.5). Conversely, the mean (+/- SD) number of larvae in feces was higher in fawns (103 +/- 119 larvae/g) than in adults 2 to 6 yr old (36.2 +/- 46 larvae/g) and 7 to 15 yr old (35.6 +/- 60 larvae/g). Mean (+/- SD) fecundity of female worms was greatest in fawns (51.6 +/- 64.8 larvae/g of feces/female worm). Deer of all ages passed more lavae in the spring. Deer from an area where year-round density was 30 deer/km2 had a mean (+/- SD) of 3.5 (+/- 1.8) adult worms; deer from the study area, with a summer density 2 deer/km2, had 3.2 (+/- 2.2) worms; however, deer at the greater density passed a greater mean number of larvae (93.8 and 57.1 larvae/g, respectively). Based on our results we propose that P. tenuis is a long-lived parasite and that most deer become infected in their first or second summer of life, and acquire few additional worms thereafter.
通过检查1991年11月至1993年5月在美国明尼苏达州东北部被车辆撞死的379只已知年龄的白尾鹿（弗吉尼亚鹿）的头部和粪便样本，确定了细颈帕拉线虫的流行率和感染强度。在311只（82%）鹿的颅骨中发现了少量成虫（平均±标准差，3.2±2.2；最多13条）；但超过三分之一（311只中的118只）受感染的鹿粪便中未排出幼虫。大多数隐性感染是不育的，因为寄生虫只存在一种性别。在鹿的椎管中未发现成年细颈帕拉线虫。小鹿成虫和幼虫的流行率（分别为68%和35%）低于老年鹿（分别为89%和63%）。45只7至15岁的鹿中有43只被感染。小鹿（2.7±1.8）和一岁鹿（3.0±2.1）成虫的平均感染强度低于7至15岁的鹿（4.1±2.5）。相反，小鹿粪便中幼虫的平均数量（103±119条幼虫/克）高于2至6岁的成年鹿（36.2±46条幼虫/克）和7至15岁的成年鹿（35.6±60条幼虫/克）。雌虫的平均繁殖力在小鹿中最大（51.6±64.8条幼虫/克粪便/雌虫）。所有年龄段的鹿在春季排出的幼虫更多。年平均密度为30只鹿/平方公里地区的鹿，成虫平均数量（±标准差）为3.5（±1.8）条；研究区域夏季密度为2只鹿/平方公里的鹿，有3.2（±2.2）条成虫；然而，密度较大地区的鹿排出的幼虫平均数量更多（分别为93.8和57.1条幼虫/克）。根据我们的研究结果，我们提出细颈帕拉线虫是一种长寿寄生虫，大多数鹿在其生命的第一个或第二个夏天被感染，此后很少再感染其他线虫。
