17 
Plerocercoid: In muscles of fish. 
Habitat. — Adult in intestine of man, dogs, cats, foxes; larva a plerocercoid in 
various fishes — common pike ( Esox Indus), ling ( Lota lota), perch ( Perea fluviatilis ) , 
several members of the salmon family ( Salmo umbla , S. trutta, S. lacustris, Thymallus 
vulgaris, Coregonus laveratus, C. albula , Onchorhynchus kisutch, and perhaps Salmo 
salar ) . 
Geographic distribution. — Reported particularly from the Baltic provinces, French 
Switzerland, and Japan. From these districts it has spread into France, Italy, Ger- 
many, Russia, Finland, Sweden, Denmark, Holland, Belgium, and Ireland; it is 
also reported for Madagascar, and a few cases are known for the United States. In 
some localities 5 to 20 per cent of the inhabitants are alleged to harbor the worm. 
Fig. 5. — Longitudinal, sagittal section 
of similar segment, showing the rel- 
ative position of the three genital 
pores. Enlarged. (After Leuckart, 
1886, 877, fig. 363.) 
Fig. 6. — Transverse section of a segment at height of 
cirrus-pouch, to show the relative position of organs. 
X 10. (After Leuckart, 1886, 878, fig. 364.) 
Fig. 7. — Dorsal view of genital organs: ov., ovary; s. g., 
shell gland; f., testicles; wt., uterus; v. d., vas deferens. 
X 20. (After Leuckart, 1886, 882, fig. 365.) 
Special medical significance. — A number of patients exhibit 
anemia, known as Bothriocepkalus-anemia. Anemia is more likely to 
develop in case of infection with this parasite than it is with any other 
tapeworm. 
Upon infection the worm grows at a rate of 31 to 32 segments per 
day, about 2.2 to about 9 cm. in total length; eggs may be found in 
the feces 21 days after infection. 
Prevention. — Eat no raw or undercooked fish. 
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