CYSTICERCOSIS.
Fig. 136.—Head of the marginate tapeworm (Tænia marginata). × 17. (Stiles, Annual Report, U.S.A. Bureau of Agriculture, 1901.)
This disease is produced by the thin- or long-necked bladder-worm (Cysticercus tenuicollis) found in cattle, sheep, and swine. The cysticercus represents an intermediate stage of development of the marginate tapeworm (Tænia marginata) of dogs and wolves.
It is by no means uncommon in Europe and America, and occurs in the body cavity of cattle, sheep, swine, and other animals, attached to the diaphragm, omentum, liver, or other organ.
When eaten by dogs or wolves, it develops into the marginate tapeworm, which was formerly confused with T. solium of man, and gave rise to the erroneous idea that the pork-measle tapeworm occurs in dogs as well as in man.
Fig. 137.—Small and large hooks of (A) Tænia marginata, (B) T. serrata, and (C) T. cœnurus. a, Small hooks; b, large hooks. × 480. (After Deffke.)
Fig. 138.—Sexually mature segment of the marginate tapeworm (Tænia marginata). cp, Cirrus pouch; gp, genital pore; n, nerve; ov, ovary; sg, shell gland; t, testicles; tc, transverse canal; ut, uterus; v, vagina; vc, ventral canal; vd, vas deferens; vg, vitellogene gland. Enlarged. (After Deffke.)