TRANSMISSION DYNAMICS OF ECHINOCOCCUS-GRANULOSUS, TAENIA-HYDATIGENA AND TAENIA-OVIS IN SHEEP IN URUGUAY
TRANSMISSION DYNAMICS OF ECHINOCOCCUS-GRANULOSUS, TAENIA-HYDATIGENA AND TAENIA-OVIS IN SHEEP IN URUGUAY
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DOI：
10.1016/0020-7519(94)00209-7
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发表时间：
1995-07-01
影响因子：
4
通讯作者：
CARBALLO, M
中科院分区：
文献类型：
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作者：
CABRERA, PA;HARAN, G;CARBALLO, M
对乌拉圭佛罗里达州绵羊体内细粒棘球绦虫、包虫病和绵羊带绦虫的传播动态进行了基线调查。本司绵羊种群出生时的平均预期寿命估计为公羊3.5岁和母羊4.8岁。细粒棘球绦虫感染的强度和流行率都随着年龄的增长而增加，没有证据表明人群中获得了免疫力。这表明细粒棘球绦虫只是相对稳定，处于平衡的流行稳定状态，估计基本繁殖率(R(0))约为1.2。42月龄和54月龄绵羊成熟幼虫种群服从负二项分布，分别为0.199和0.556。平均每年增加包囊1.0 5个，感染压力为每年0.174个感染，即每次感染由693.6个卵组成，每产生6.0 3个包囊。包虫病和羊毛虫的感染强度和感染率均不随年龄增长而增加。这表明两种寄生虫对再感染都获得了免疫力，处于平衡的高流行稳定状态，估计R(0)为4.2-5.8。高龄组细粒棘球绦虫存活率、生育力和包虫包囊存活率均较低。讨论了不同传播水平的寄生虫对潜在控制策略的影响。
A base-line survey was carried out on the transmission dynamics of Echinococcus granulosus, Taenia hydatigena and Taenia ovis in sheep in the Department of Florida, Uruguay. Mean life expectancy at birth of the sheep population in this Department was estimated at 3.5 and 4.8 years for male and female sheep, respectively. Both intensity and prevalence of E. granulosus infection increased with age providing no evidence that immunity was acquired in the population. This revealed that E. granulosus was only relatively stable and in an equilibrium endemic steady state with an estimate of the basic reproduction ratio (R(0)) of about 1.2. The mature larval population in sheep was over-dispersed with parameter k, from fitting a negative binomial, being 0.199 and 0.556 in 42- and 54-month-old sheep, respectively. The mean number of cysts increased by 1.05 cysts per year and the infection pressure was calculated as 0.174 infections per year, implying that each infection consisted of 693.6 eggs to produce 6.03 cysts. Neither intensity nor prevalence of infection with T. hydatigena or T. ovis increased with age. This indicated that immunity was acquired to reinfection by both parasites and they were in an equilibrium hyperendemic steady state with an estimated R(0) of 4.2-5.8. Viability and fertility of E. granulosus, and viability of T. hydatigena cysts in the older age groups were low. The effects of the different transmission levels of the parasites on potential control strategies are discussed.