THE MORTALITY AND FECUNDITY OF HAEMONCHUS-CONTORTUS IN PARASITE-NAIVE AND PARASITE-EXPOSED SHEEP FOLLOWING SINGLE EXPERIMENTAL INFECTIONS
THE MORTALITY AND FECUNDITY OF HAEMONCHUS-CONTORTUS IN PARASITE-NAIVE AND PARASITE-EXPOSED SHEEP FOLLOWING SINGLE EXPERIMENTAL INFECTIONS
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DOI：
10.1016/s0020-7519(05)80009-8
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发表时间：
1992-05-01
影响因子：
4
通讯作者：
SMITH, G
中科院分区：
文献类型：
--
作者：
COYNE, MJ;SMITH, G
实验中，在3万只弯纹夜蛾幼虫的中度免疫感染终止后的第3、9、12和20周，暴露于寄生虫的羔羊和未感染寄生虫的对照只被3万只弯纹夜蛾幼虫感染一次。与未感染寄生虫的对照组相比，先前暴露的羔羊在3周时受到攻击，其弯曲螺旋虫的总负荷显著减少。暴露于寄生虫的羔羊和未感染寄生虫的羔羊在9周或之后的总弯曲螺旋虫负荷没有差异。与未接触寄生虫的羔羊相比，先前接触寄生虫的羔羊中发现的雌性蠕虫明显更小。平均每只雌虫每天产卵4700个卵。羔羊先前与寄生虫的接触对寄生虫的繁殖力没有影响。各种数学模型被用来检验寄生虫的繁殖力。发现寄生虫的繁殖力在最初的攻毒后时期增加，在攻毒感染后约58天达到恒定值。没有观察到密度对繁殖力的依赖性约束。
Parasite-exposed lambs and their parasite-naive controls were experimentally infected once only with 30,000 H. contortus larvae at 3, 9, 12, and 20 weeks following termination of a moderate immunizing infection of 30,000 H. contortus larvae. Previously exposed lambs, challenged at 3 weeks, had a significant reduction in the total H. contortus worm burden as compared to parasite-naive controls. No difference in the total H. contortus worm burden was found between parasite-exposed or parasite-naive lambs challenged at 9 weeks or thereafter. Female worms were found to be significantly smaller in lambs previously exposed to the parasite as compared to those found in parasite-naive lambs. The average parasite fecundity was 4700 eggs per female worm per day. Previous exposure of the lambs to the parasite had no effect on parasite fecundity. Various mathematical models were used to examine parasite fecundity. Parasite fecundity was found to increase in the initial post-challenge period reaching a constant value approximately 58 days after challenge infection. No density-dependent constraints on fecundity were observed.