Observations on parasite-host relationships of Echinococcus multilocularis Leuckart, 1863, in North Dakota.

Abstract

Red foxes, Vulpes vulpes (Linnaeus), and small mammals were collected and examined during 1965–69, to investigate parasite–host relationships of Echinococcus multilocularis Leuckart, 1863, in North Dakota. Comparative studies of this cestode were carried on concurrently through experimental infection of carnivores and rodents. In winter, red foxes in North Dakota exhibited high rates of infection of comparatively low intensity. Deer mice, Peromyscus maniculatus (Wagner), and voles, Microtus pennsylvanicus (Ord), were important intermediate hosts, but the larvae in deer mice produced fewer protoscolices. The strains of E. multilocularis from North Dakota and from St. Lawrence Island, Alaska, differ biologically, as indicated by findings in experimentally infected rodents, but they could not be distinguished morphologically at the infraspecific level. Helminths recorded from red foxes in North Dakota are listed, and some ecological data are presented and discussed.