Small Animal Intestinal Parasites

What is zoonosis

Transmission of a disease from an animal to a human

How are nematodes/roundworms diagnosed

Fecal flotation with zinc centrifugation - gold standard

What is the common roundworm in dogs and cats

Toxocara canis

Transmission of toxocara canis or roundworms in general

Fecal-oral, transplacental infection is most common

What zoonotic disease does toxocara canis cause

Ocular larva migrans

Where do roundworms live

Small intestine

How do we treat roundworms

Piperazine, pyrantel, or fenbendazole

What are the most common species of hookworms

Ancylostoma caninum and Uncinaria stenocephala

What are some signs of patients with hookworms

Hemorrhagic diarrhea and severe anemia (especially in young puppies)

How are hookworms transmitted

Fecal-oral, transmammary (common in puppies), percutaneous infections

What zoonotic disease can hookworms cause

Cutaneous larva migrans - occurs via skin penetration

In a percutaneous hookworm infection, what is the route or how do they travel

Travel through the skin to the lung, where they molt and are brought back up for us to swallow, which then bring them to the small intestine

How do we treat hookworms

Fenbendazole, pyrantel

What is the common whip worm we should know

Trichuris vulpes

Characteristics of whipworms

Large intestinal parasite

Eggs have bipolar plugs on the ends

How are whipworms transmitted

Fecal-oral transmission only

What can severe infection of whipworms lead to

Hyperkalemia and hyponatremia (looks like Addison’s, so it is called pseudo-Addison’s)

How do we treat whipworms

Fenbendazole, but can be prevented with Milbemycin

What are the common nematodes we see

Roundworms

Hookworms

Whipworms

What kind of parasite is a tapeworm

Cestode

What is the most common tapeworm in dogs and cats

Dipylidium caninum - requires a flea as intermediate host and can be inadvertently swallowed during grooming

What are other tapeworms we can see

Echinococcus granulosus

Taenia spp

How can echinococcus granulosus and taenia spp be transmitted

Ingestion of ineffective hydatid cysts during predation of rabbits, rodents, birds

Characteristics or tapeworms

Flat and segmented, eggs are contained within segments

Segments are called proglottids

Proglottid segments are released from end of worm and shed in feces - they look like a grain of rice

How to diagnose tapeworms

The “grains of rice” may be seen in feces or around the anus of the pet

Eggs are not always seen on a fecal float unless proglottid breaks before being passed in the feces and eggs are released

What is the “grain of rice” that may be seen on the anus

Progottid segments

Treatment to tapeworms

Praziquantel is treatment of choice (Drontal and Profender)

What are the types of trematodes we can see

Flukes

Giardia

Coccidia

What is the most common fluke we see

Fasciola hepatica - common live fluke

Where are the adult fasciola hepatica flukes located

Hepatic bile ducts

Where is fasciola hepatica usually seen? In what species

Cattle or sheep that have been grazing in endemic areas

What is part of the flukes life cycle

They need a snail as an intermediate host so they are most commonly in areas of high rainfall or moist environments (where snails are)

How to treat flukes

Albendazole

What is the lifecycle of giardia (based on the power page on vet tech prep)

Life cycle of flagellated protozoan (trophozoites) and infective resistant cysts

How is giardia transmitted

Fecal-oral transmission, often through contaminated water sources

What are sings of giardia typically

Watery diarrhea

Is giardia zoonotic?

Potentially zoonotic - most species carried by dogs and cats are not infectious to us but there is always a potential so it should be treated as zoonotic

How do we diagnose giardia

Fecal flotation, but Giardia ELISA tests are the most sensitive

Trophozoites may be seen on a direct smear of a fresh fecal sample

Treatment to giardia

Fenbendazole (Panacur) or Metronidazole (Flagyl)

How do animals get giardia

They drink contaminated water sources which has the infective cysts

Do trophozoites infect us?

No - it is the cyst that is at its infective stage → they swallow the cyst in the water and hatch to become trophozoites

Trophozoites also cannot survive in the environment once passed through feces

What are coccidia

Single celled internal microscopic parasites

What is the most common coccidia in cats and dogs

Isospora

What is the most common coccidia usually seen in birds/poultry and rabbits

Eimeria

Are coccidia species-specific

Yes - so Isospora are not infective to humans, and eimeria is not infective to dogs and cats

What causes hepatic coccidiosis in rabbits

Eiemeria stiedai - cau

How do we diagnose coccidia

Fecal float or sometimes direct smear