Dog-specific Worms
Cestodes (tapeworms)
Cestodes, or tapeworms, owe their name to the flat, tape-like shape of their bodies. They parasitise the small intestine of the final host where they can grow to considerable lengths.
Taenia pisiformis
This tapeworm can grow up to 2 meters long. The final gravid segment can measure 8 – 10 x 4.5 mm. The large head is round in front, and has two rings of hooks that have a long straight root segment and bear four sucking lips.
Taenia multiceps
This tapeworm grows to about 1 meter long and 5 mm wide with some 250 segments. The small pear-shaped head has four powerful suckers and a double ring of large hooks. The neck is thin and long.
Echinococcus granulosus
Echinococcus granulosus grows to between 2.5 and 6 mm long. The final gravid proglottis is clearly larger than the front 2 or 3. At the scolex there are four suckers and a ring of 30 – 42 hooks with which it digs deep into the villi of the small intestine.
Echinococcus multilocularis
Echinococcus multilocularis appears in its adult form predominantly in foxes. Mature worms achieve lengths between 1.5 and 3 mm. The last gravid proglottis is smaller than the other 4 or 5. The scolex has a ring with 26 to 36 small hooks.
Dipylidium caninum (flea tapeworm)
Dipylidium canium is the most common tapeworm in cats and dogs. The entire chain of parasitic flatworm segments (strobila) is approx. 20 – 45 cm long. There are four suckers and a rostellum bearing 3 to 5 rings of hooks on the small head. The gravid segments are approx. 7 to 12 cm long and 2 to 3 mm wide and resemble cucumber seeds.
Mesocestoides lineatus
This tapeworm species grows up to 40 cm long and 2 mm wide and is identifiable by a paruterine organ on the final proglottis. The head has four suckers, but no hooks.
Nematodes (roundworms):
Nematodes are roundworms of varying sizes, which live in the intestine of their host. They attach themselves via their lip-disks or hooks to the wall of the intestine and feed on mucous, blood or intestinal contents.
Ascarids (maw worms):
Toxocara canis
Maw worms are evenly round, and resemble spaghetti. Toxocara canis grows 10 to 18 cm long. The front end has three lips with sensory papillae and short, striped cervical wings that are 2.5 mm in length.
Toxascaris leonina
Maw worms are evenly round, and resemble spaghetti. Toxascaris leonina grows 7 to 10 cm long. The front end has three lips with sensory papillae and long, narrow cervical wings.
Hookworms:
Ancylostoma caninum
Adult hookworms are characterized by teeth in their oral cavity. Ancylostoma caninum has two large dental plates, each of which has three teeth. The worm grows to approximately 10 to 16 mm.
Uncinaria stenocephala
Adult hookworms are characterized by teeth in their oral cavity. Uncinaria stenocephala has a mouth opening with two cutting disks. The worm grows to approx. 5 to 10 mm.
Whipworms:
Trichuris vulpis
These worms, which grow up to 7.5 cm, occur mainly in dogs and foxes. They anchor themselves in the mucous membrane of the appendix and large intestine with their whip-shaped threadlike front end. The wide back end moves freely within the intestinal lumen.