. The dog as a carrier of parasites and diseases. Dogs as carriers of disease; Dogs. PAKASITES AND PARASITIC DISEASES OE DOGS 29 segments are often seen and referred to as rectal worms or pin worms. The common double-pored tapeworm has a larval stage in fleas and the biting Hce of dogs. The fleas become infected while they are flea larvae feeding on the organic matter in trash, the larval fleas swallow- ing the tapeworm eggs in this trash. Biting lice swallow the eggs while feeding on the contaminated sldn of the dog. In these insects the tapeworm eggs hatch and the escaping embryo develops to
. The dog as a carrier of parasites and diseases. Dogs as carriers of disease; Dogs. PAKASITES AND PARASITIC DISEASES OE DOGS 29 segments are often seen and referred to as rectal worms or pin worms. The common double-pored tapeworm has a larval stage in fleas and the biting Hce of dogs. The fleas become infected while they are flea larvae feeding on the organic matter in trash, the larval fleas swallow- ing the tapeworm eggs in this trash. Biting lice swallow the eggs while feeding on the contaminated sldn of the dog. In these insects the tapeworm eggs hatch and the escaping embryo develops to a larval tapeworm in. the body of the insect. When dogs, annoyed by the itching and irritation due to these insects, hunt them out and swallow them, the tapeworm larvae become adult tapeworms in the intestine of the dog. This tapeworm sometimes occurs in man, especially in children, as a result of the accidental swallowing of infested fleas or Mce by persons. A larger group of tapeworms is made up of forms which have only two circlets of hooks (fig. 27) and have a genital pore on only one side of each segment (fig. 28). The thick-shelled eggs do not occur in egg capsules but in a uterus from which some eggs escape into the intesti- nal contents and feces. The eggs (fig. 29) occur as isolated specimens. Figure 28.—The gid tapeworm, MuUiceps multiceps. Entire worm. Actual size. From Hall, 1910. if' in the feces. The segments, usually containing only a part of the original egg content, escape in the feces and in time break up, releasing the remaining eggs, which are washed about on the groimd and on vegetation by the rain. When such eggs are swallowed by suitable hosts, such as sheep, cattle, swine, hares, rabbits, etc., the hosts varying with different species of tapeworms, the eggs hatch and each releases an embryo which penetrates the walls of the digestive tract and develops in some tissue (fiver, lungs, muscles, brain, intermuscular or subcutaneous connective tissue, etc.)
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