Environmental adaptation of Echinococcus in South America

对乌拉圭细粒棘球绦虫的流行病学现状及环境适应性进行了研究。乌拉圭最重要的产业是畜牧业。问卷调查显示，约有20%的居民在家屠宰羊。狗在农场里可以接触到羊的内脏。将639只羊的内脏切片，检查有无包虫病。绵羊包虫病患病率约为40%。检羊包虫病平均强度为1.67。大多数羊的囊肿很少。睡眠中包虫病的患病率随着年龄的增长而增加。半数成年羊患有包虫囊肿。每年平均增加1个囊肿。3岁以上羊有生殖力囊肿，5岁以上羊患病率约为10%。5岁以上绵羊平均可育囊肿数为4个。每个可育囊肿的平均原头节数为1437个。大多数可育囊肿含有少于500个原头节。我们通过槟榔碱调查来检查狗的患病率。农场中颗粒棘球绦虫的患病率约为23%或更多。城镇犬类患病率低于农场犬类。在对镇上流浪狗的尸检调查中，77只狗中有3只被感染。对乌拉圭产牛羊颗粒绦虫COI基因序列进行了分析，以确定遗传变异。结果表明，普通绵羊品系分布在乌拉圭。建立了一种夹心ELISA法检测犬颗粒棘球绦虫感染的粪原抗原。采用ELISA法监测实验感染犬粪原抗原排泄的时间过程。颗粒棘球绦虫的绦虫期在免疫抑制的鸟类小肠内发育，但未从这些动物体内恢复完全成熟的寄生虫。

Epidemiological status and environmental adaptation of Echinococcus granulosus in Uruguay were studied. Most important industry of Urugyay is livestock industry. A questionnaire survey shown that about 20% of the inhabitants carried out home-slaughtering of sheep. Dogs have access to the viscera of sheep in farms.Viscera of 639 sheep were sliced and examined for hydatid cysts. Prevalence of hydatid cysts in sheep was about 40%. and mean intensity of hydatid cysts in examined sheep was 1.67. Most sheep harbored few cysts. Prevalence of hydatid disease in sleep increased with age. Half of adult sheep had hydatid cyst. Average increase in number of cysts per year was about 1. More than 3 years old sheep harbored fertile cysts, Prevalence in more than 5 years old sheep was about 10%. Mean number of fertile cysts in more than 5 years old sheep was 4. The mean number of protoscoleces per fertile cyst is 1,437. Most of the fertile cysts contain less than 500 protoscoleces.We examined the prevalence in dogs by arecoline survey. Prevalence of E.granulosus in farms is about 23% or more. Prevalence in dogs in town is lower than that in farm. In a survey by necropsy of stray dogs in town, 3 of 77 dogs were infected.DNA sequence of COI of E.granulosus from sheep and cattle in Uruguay were analyzed for determinination of genetic variation. The results showed that common sheep strain distribute in Uruguay.We developed a sandwich ELISA using monoclonal antibody for detection of coproantigen in E.granulosus infected dogs. The time course of coproantigen excretion from dogs experimentally infected with E.granulosus was monitored by this ELISA.Tapeworm stage of E.granulosus developed in the small intestine of immunosuppressed jirds, but fully matured parasite were not recovered from these animals.