On the Ecology and Distribution of Echinococcus spp. (Cestoda: Taeniidae) and Characteristics of Their Development in the Intermediate Host

• Main Author: Rausch, Robert L.
• Format: Text
• Language: unknown
• Published: DigitalCommons@University of Nebraska - Lincoln 1967
• Subjects: Parasitology; Arctic; Renard; Alopex lagopus; Arctic Fox; Iceland; Alaska
• Online Access: https://digitalcommons.unl.edu/parasitologyfacpubs/480; https://digitalcommons.unl.edu/context/parasitologyfacpubs/article/1491/viewcontent/Rausch_1967_AP_On_the_Ecology_and_Distribution_of_Echinococcus_spp_Cestoda_Taeniidae_and_Characteristics.pdf

Echinococcus granulosus (Batsch, 1786) and E. multilocularis Leuckart, 1863 [syn. Alveococcus multilocularis (Leuckart, 1863) Abuladze, 1960] are distinguished by well defined biological and developmental characteristics. Obligatory predator-prey relationships of the hosts segregate the two species ecologically under natural conditions. The larval stage of E. granulosus develops slowly in long-lived ungulates, while that of E. multilocularis becomes infective within a few months in intermediate hosts (rodents) having a life expectancy of less than a year. Existing parasite-host relationships of these cestodes had become established at least as early as late Pleistocene time, and two biologically distinct forms of E. granulosus can be defined; one, involving cervids as the intermediate host, has a holarctic distribution at higher latitudes, and the second is adapted to species of mammals of which many have been domesticated. The distributional history of the latter form, widely introduced to other parts of the world from Eurasia, has been traced since the time of colonization of Iceland (ca. 870 A.D.). Apparently restricted by host requirements, E. multilocularis is limited distributionally to the northern hemisphere. Its known range includes the endemic region of central Europe, Bulgaria, Turkey, the Soviet Union east of about Long. 25° E., and certain islands, including the Middle Kuriles and some of the Japanese islands. In North America the known range of E. multilocularis at high latitudes corresponds closely to that of the arctic fox, Alopex lagopus L. The extent of the recently discovered endemic region in central North America has not been determined. Published host-records for E. multilocularis have been included, along with a summary of findings in canine animals and rodents in Alaska. Developmental characteristics of the larval stage of these cestodes will be defined in subsequent sections of this paper. French language abstract: Echinococcus granulosus (Baitsch, 1786) et E. multilocularis Leuckart, ...