Veterinary Parasitology: Key Concepts on Worms, Protozoa, and Diagnosis

Toxocara

Roundworm (Ascarid)

How is Toxocara transmitted?

transplacental, transmammary, and egg ingestion via environment or transport host.

Toxocara Clinical Signs

Young primarily affected; may cause stillbirths/neonatal death, malnutrition, impaired growth, emaciation, potbellied appearance, rough hair coat, poor muscle development, vomiting, and diarrhea.

Toxocara Diagnosis

Diagnosis is made by finding eggs in feces and/or adult worms in vomit.

Toxocara Treatment

Treatment includes numerous anthelmintics and sanitation.

Ancylostoma caninum

Hookworm

Ancylostoma caninum tranmission?

transmammary, larvae ingestion, or skin penetration via environment.

Ancylostoma caninum Clinical Signs

Primarily affects puppies; causes anemia due to blood feeding, chronic diarrhea with blood, weakness, depression, and lethargy.

Ancylostoma caninum Diagnosis

by finding eggs and/or adults in feces.

Ancylostoma caninum Treatment

Treatment includes various anthelmintics and sanitation.

Ancylostoma tubaeforme

Ancylostoma braziliense

Uncinaria steocephala

Hookworm

Ancylostoma tubaeforme

Larvae ingestion or skin penetration via environment, transmammary has not been demonstrated

what parasite do cats require immunity?

Ancylostoma tubaeforme

Trichuris vulpis

Whipworm

transmitted directly via infective egg ingestion, little to no immunity=adult infections common

Trichuris vulpis Clinical Signs

Causes anemia due to blood feeding, diarrhea (possibly bloody), vomiting, weight loss, and dehydration.

Trichuris vulpis Diagnosis

Diagnosis is made by finding eggs in feces, which may be few and missed.

Trichuris vulpis Treatment

Treatment includes various anthelmintics, rapid reinfection, and sanitation.

Dipylidium caninum

Tapeworm with a scolex (head) and strobila (body) made up of proglottids.

Dipylidium caninum Clinical Signs

Rarely causes health problems; heavy infections may lead to dull coat and anorexia.

Dipylidium caninum Diagnosis

Diagnosis is made by finding gravid proglottids and/or eggs in feces.

Dipylidium caninum Treatment

Treatment includes various anthelmintics and control of fleas.

Isospora

Single cell microscopic protozoan (~12 species) that is highly contagious in puppies.

Isospora Clinical Signs

Causes severe diarrhea (mucoid/bloody), dehydration, weight loss, and may present with upper respiratory signs.

Isospora Diagnosis

Diagnosis is made by signs and/or oocysts in feces.

Isospora Treatment

Treatment includes some drugs, symptomatic therapy, and sanitation.

Toxoplasma clinical signs

Usually asymptomatic; may cause fever, anorexia, lethargy, and ocular/nervous signs.

Toxoplasma Diagnosis

Diagnosis is made through serology and finding oocysts in feces.

Toxoplasma Treatment

Usually none needed; some antibiotics and anti-protozoal drugs may be used.

Giardia canis

Single cell microscopic flagellar protozoan; most common source of infection from contaminated water.

Giardia canis Clinical Signs

Causes mild enteritis and chronic intermittent diarrhea, more severe in puppies.

Giardia canis Diagnosis

Diagnosis is made by finding infective forms (cysts) in feces.

Giardia canis Treatment

Treatment includes some drugs, symptomatic therapy, and avoiding contaminated water.

Filaroides - Canine

Canine lungworm with an ovo-viviparous life cycle and auto infection.

Filaroides - Canine transmission to pups

-Consuming fecal larvae

- Bitch saliva when licking

Filaroides - Canine Clinical Signs

Usually asymptomatic; may cause occasional cough/dyspnea.

Filaroides - Canine Diagnosis

Diagnosis is made by presence of L1 in feces/sputum ad discovered on necropsy.

Filaroides - Canine Treatment

Many anthelmintics are effective; endoscopic removal of obstructing nodules may be necessary.

Aelurostrongylus - Feline

Feline lungworm with an ovo-viviparous life cycle

Aelurostrongylus - Feline transmission

L1 passed in feces intermediate host=smail, paratenic host=birds, rodents

Aelurostrongylus - Feline Clinical Signs

Usually mild; may cause cough/dyspnea.

Aelurostrongylus - Feline Diagnosis

Diagnosis is made by presence of L1 in feces.

Aelurostrongylus - Feline Treatment

Treatment includes fenbendazole at high doses for multiple days and ivermectin once.

Paragonimus - Fluke

Rare lung fluke with a complex life cycle involving multiple hosts. (eggs in feces, miracidium, snail, crawfish/crab, (metacercaria in muscle),host

Paragonimus -Fluke transmission

Migrate to lungs

• Encapsulated by fibrous cyst

• Fistula to bronchioles for egg excretion

Paragonimus - Fluke Diagnosis

Diagnosis is made by finding typical fluke eggs in feces.