Campbell B G, Little M D
Department of Tropical Medicine, Tulane Medical Center, New Orleans, Louisiana 70112.
Am J Trop Med Hyg. 1988 May;38(3):568-73. doi: 10.4269/ajtmh.1988.38.568.
Twenty of 94 (21.4%) Rattus norvegicus trapped in New Orleans, Louisiana, between April 1986 and February 1987 were infected with Angiostrongylus cantonensis (3-62 worms per rat). This is the first report of the parasite from North America. A carnivorous snail, Euglandina rosea, was found experimentally to be able to serve as both an intermediate and a paratenic host. Other locally occurring gastropods that were successfully infected experimentally included Mesodon thyroidus, Anguispira alternata, Bradybaena similaris, Subulina octona, Polygyra triodontoides, Vaginulus ameghini, Philomycus carolinianus, Deroceras laeve, Limax flavus, and Lehmannia poirieri. Laboratory reared, 4- to 5-week-old M. thyroidus and D. laeve were able to support the development of small numbers of larvae to the third stage. First stage larvae of A. cantonensis in the feces of experimentally infected rats were found not to migrate out of the fecal pellet; this behavior favors the infection of feces-consuming gastropods. Twenty heavily infected L. flavus were observed over a period of 2 months, and shedding of third stage larvae of A. cantonensis was never seen. While factors support the spread of A. cantonensis in rats in the southern United States, the probability of human infection is uncertain since the parasite is transmitted primarily by ingestion of raw intermediate and paratenic hosts.
1986年4月至1987年2月间，在路易斯安那州新奥尔良捕获的94只褐家鼠中，有20只（21.4%）感染了广州管圆线虫（每只大鼠感染3 - 62条虫）。这是该寄生虫在北美的首次报告。实验发现，肉食性蜗牛玫瑰色芒螺既能作为中间宿主，也能作为转续宿主。其他在当地出现且实验感染成功的腹足类动物包括甲状腺中齿螺、交替虹蛹螺、相似扁卷螺、八角土蜗、三齿多旋螺、阿氏嗜黏液蛞蝓、卡罗来纳嗜黏液蛞蝓、光滑双脐螺、黄蛞蝓和波氏后鳃螺。实验室饲养的4至5周龄甲状腺中齿螺和光滑双脐螺能够支持少量幼虫发育到第三阶段。在实验感染大鼠的粪便中发现，广州管圆线虫的第一期幼虫不会从粪粒中迁出；这种行为有利于感染以粪便为食的腹足类动物。在2个月的时间里观察了20只重度感染的黄蛞蝓，从未见到广州管圆线虫第三期幼虫的排出。虽然有因素支持广州管圆线虫在美国南部大鼠中的传播，但由于该寄生虫主要通过摄入生的中间宿主和转续宿主传播，人类感染的可能性尚不确定。
