Toxascaris leonina

"Ascarids (roundworm)"

egg

Toxocara canis

"Ascarid (roundworm)"

egg

host: dog 

Toxocara cati (or felis)

"Ascarid (roundworm)"

egg

host: cat

(similar in structure to canis but smaller in diameter) 

 Adult

Ascarid (roundworm)

dog/cat: small intestine

(Toxocara canis, Toxocara cati, Toxascaris leonina)

 *may vary in length from 3-18 cm and when passed in feces are usually tightly coiled.

*lay eggs in small intestine, pass out in feces, consumed by new host, tracheal migration, returns to small intestine to mature(possible infection transmammary/placental

*viseral larva migrans- zoonoses of roundworms

*as an animal ages they have a higher resistance to ascarid infection 

Ancylostoma caninum (smaller ova)

canine hookworm egg 

Uncinaria stenocephala (larger ova)

northern canine hookworm egg 

*eggs are ellipsoidal, thin walled, and contain 8-16 cell morula when passed in feces 

Adult hookworm

(Ancylostoma caninum, Uncinaria stenocephala)

*Hookworms are nematodes that attach to the small intestinal mucosa and suck blood.  A. caninum has three pairs of ventral teeth that are used to attach itself to the intestine 

*mate and produce eggs in small intestine, eggs passed in feces, molts and matures with warmth, swallowed by host/or penetrates skin, migrates through body tissues to lungs, tracheal migration, returns to intestine to attach and mature

*Cutaneous Larva Migran=zoonotic hookworm 

Trichuris vulpis

canine whipworm egg 

*eggs have a thick, yellow-brown, symmetric shell with polar plugs at both ends (double operculum).  Eggs are unembryonated (not larvated) when laid 

Adult canine

Whipworms

(Trichuris vulpis)

*attaches to the wall of the cecum or colon and produce eggs, eggs passed in feces, cells mature to form infective larva, egg is ingested (only way) by host and hatches, develops(molts) in the small and large intestine, new adult migrates back through the colon to the cecum and attaces to the intestinal wall.

Syphacia sp.

rodent pinworm eggs

 (*Syphacia obvelata, Syphacia muris)

Syphacia sp. (muris&obvelata)

Adult pinworms of rodents

*usually found in cecum, transmitted by the ingestion of the eggs which are light enough to aerosolize (making control difficult).

*can be easily transmitted among mice, rats, hamsters, and gerbils.

*not of zoonotic significance 

Taenia Pisiformis

Adult tapworm of dogs

*scolex has three suckers, and a rostellum with hooks

*attaches to the wall of the small intestine by means of the scolex

*the body is composed of segments (proglottids), posterior=mature(contain reproductive organs), and gravid(contains the eggs).

*absorbs nutrients from the intestinal contents through its body wall 

*embryonated (gravid)eggs/segments pass in feces, IH(rabbit/rodent) ingests infective eggs, which hatch and develop, the host (dog) ingests the infected IH freeing the cysticerci which attach to the intestinal wall to mature 

Taenia pisiformis

tapeworm of dogs 

Taenia taeniaformis

feline tapeworm

*adults live in intestines of dogs/ gravid proglottids pass in feces, eggs ingested by rabbit or rodent/ developes in IH/ DH ingests IH/ develops to adult 

Dipylidium caninum

tapeworm of dogs and cats

*Mature cestodes are in small intestine, gravid segments break off and pass out in feces, flea larva ingests infective eggs- which will hatch and develop into cysticercoids, host ingests infected flea or louse, freed during digestion the tapeworms attach to intestinal wall to mature. 

Dipylidium caninum

tapeworm of dog/cat egg packet 

Isospora sp.

Protozoan parasites (Coccidia)

*Sporulated oocyst* 

*oocysts pass in feces-oocysts develop to infective stage in soil and feces-host ingests sporulated oocysts- oocysts excyst, and sporozoites invade intestinal epithelial wall-reproduces asexually in the cerls of the small intestine forming meronts- after several generations oocysts are formed 

Physaloptera rara

feline/canine stomach worm

*Nematode*

*eggs are laid in stomach-beetle(cockroach, cricket) ingests eggs-hatch/larvae develop to infective 3rd stage-Host ingests infected beetle-larvae mature to adult stage

* Attaches to wall of stomach