Parasitic Diseases Flashcards by Jo Lawrence

What Anaplasma species infect ruminants?

Sheep/goats - Anaplasma ovis. Rare disease
Transmissible hemolytic disease of cattle - Anaplasma marginale

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What clinical signs does anaplasmosis cause? How is it spread?

Anemia and fever
Spread via Dermacentor ticks and fomites. Recovered animals are reservoirs.

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What agent causes red water, Texas cattle fever, and cattle tick fever?

Babesia bovis and B. bigeminia

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Where is Babesiois a concern? How is it spread?

South America and less developed countries in tropical/sub-tropical regions
Not found in smaller ruminants in the US. Reportable
Spread via Boophilus ticks

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What clinical signs does babesiois cause?

Kidney/liver failure due to hemolysis. Encephalitis

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What coccidia species is of primary concern?

Eimeria. Relatively host- and host-cell specific.

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What are the clinical signs and lesions associated with coccidiosis?

Primarily hemorrhagic diarrhea in young animals. Mostly watery in calves. Adults can carry and shed but rarely show disease.
Sheep: Ileum, cecum, and upper colon usually most affected and may be thickened, edematous, and inflamed.
Goats: Small intestine is congested, hemorrhagic, or ulcerated with scattered plaques.

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How is coccidia spread, diagnosed, and controlled?

Spread via ingestion of sporulated oocysts.
Diagnosed if numerous oocysts >20,000/g in fresh fecal sample
Control with coccidiostats and isolation of affected animals

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What agent causes cryptosporidiosis? What are the clinical signs and associated lesions?

Protracted, watery diarrhea and debilitation. May contain blood, mucus, bile, and undigested milk. Young ruminants most commonly affected, particularly calves.
Emaciation, enteritis with crypt hyperplasia, and villous atrophy/fusion.

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What is the pathogenesis or cryptosporidiosis?

Fecal-oral spread of sporulated oocysts, resistant to desiccation. Invades cells but does not enter the cytoplasm.

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Where does Toxoplasma gondii survive within the body?

Obligate intracellular protozoa.

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What are the clinical signs of T. gondii infection?

Major cause of abortion in sheep and goats, less so in cattle. See placentitis, abortion, stillbirth, weak neonates, penumonia, and encephalitis.
Adult sheep usually asymptomatic, goats may die.
Infection 1st trimester - Resorb
2nd trimester - Abort. May see small white foci in cotyledons.
3rd trimester - Weak lambs with high perinatal mortality

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What can chronic cases of Giardia result in? How is it treated?

Poor doers with weight loss and unthriftiness.
Metronidazole

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Describe Neospora caninum.

Cause of abortion in cattle between 3rd and 7th month, no other signs.

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Describe sarcocystosis in ruminants. What type of host are ruminants? What species affect ruminants? Why do clinical signs occur?

Single cell protozoan.
Ruminants are intermediate hosts while carnivores are definitive hosts. Dogs definitive hosts for smaller ruminants. Cats, dogs, and primates are definitive hosts for the cattle and pig species.
Sarcocystis hominis - Cattle
Sarcocystis suihominus - Pigs
Separate species affect sheep and goats
Most infections in intermediate hosts are asymptomatic, but problems arise when the parasite is actively encysting. Causes abortion in cattle and encephalitis in sheep.

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What agent causes trichomoniasis? What conditions does it cause?

Tritrichomonas fetus, a pear-shaped flagellate causing cattle venereal disease.
Causes abortion in cattle and diarrhea in cats.
Bacterin exists, but best managed through test/cull and AI.

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What are the principal stomach worms of sheep and goats?

Haemonchus contortus, Teladorsagia (Ostertagia) circumcincta, Ostertagia trifurcata, Trichostrongylus axei

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What is the barber pole worm? Where does it live?

Haemonchus contortus, the most important internal parasite of sheep and goats.
Attaches to the abomasum where it feeds on blood

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What are the clinical signs of Haemonchus contortus? How is worm burden evaluated? How can be it be controlled?

Causes severe anemia, weight loss, decreased milk production, poor wool growth, and bottle jaw due to hypoproteinemia.
Assess with FAMACHA scoring
Control with sanitation and pasture management

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What is Ostertagia circumcincta now known as?

Teladorsagia circumcincta

What is the life cycle and type of disease caused by T. circumcincta and O. trifurcata? What alterations in the abomasum do they cause?

Life cycle similar to Haemonchus, but Ostertagia can overwinter in pasture.
Type 1 - Diarrhea in young animals
Type 2 - Emergence of arrested larvae, causing signs similar to Haemonchus
Larvae induce hyperplasia of abomasal epithelial glands, resulting in increase of gastric pH from 2 to 7. Leads to malnutrition

What is the most pathogenic and costly of the cattle nematodes?

Ostertagia ostertagi

What clinical signs does Ostertagia ostertagi cause?

Moroccan leather or cobblestone appearance to abomasum due to disruption of cells from development and emergence of larvae from abomasal glands
Type 1 - Diarrhea, young animals
Type 2- - Adults. Associated with emergence of hypobiotic larvae. Diarrhea, hypoproteinemia, anemia, and fever

What is genus of the nodular worm? Where does it infect?

Oesophagostomum sp.
Primarily large intestine, occasionally the distal small intestine.

What is the pathogenesis and clinical signs of Oesophagostomum?

Penetrates large intestinal mucosa, with resulting inflammation leading to caseous nodules that mineralize. Causes weakness, lethargy, unthrifitiness, diarrhea, and/or constipation

What is the meningeal worm? What are the definitive, intermediate, and aberrant hosts?

Parelaphostrongylus tenuis Definitive - White Tailed Deer Intermediate - Snail Aberrant - Sheep and goats, camelids, elk, caribou, and moose

What clinical signs does Parelaphostrongylus tenuis cause?

Neurological disease in aberrant hosts from migration of worms to meninges. Signs usually develop in the fall.

What are the common stomach worms of cattle?

Haemonchus placei, Ostertagia ostertagi, and Trichostrongylus axei

What are the lungworms of ruminants? What conditions do they cause?

Dictyocaulus, Protostrongylus, and Muellerius spp. Fog fever, husk, and verminous pneumonia

What lungworms infect cattle?

Dictyocaulus viviparus

What lungworms infect sheep and goats?

D. filaria, Protostrongylus rufescens, and Muellerius capillaris

What environmental conditions are lungworms associated with? What clinical signs do they cause?

Associated with cooler temperatures. Cause respiratory signs (coughing, dyspnea, nasal discharge), weight loss, unthriftiness, and bronchitis/pneumonia

What species of lungworm require an intermediate host?

Protostrongylus and Muellarius. Snail or slug intermediate host

Describe infection with Monesia expansa.

Cestode. Infects small intestine. Indirect life cycle with soil mite intermediate host. Generally no clinical signs. Characteristic triangular-shaped eggs.

What species is the fringed tapeworm? Describe infection.

Thysanosoma actinoides. Resides in duodenum, bile, and pancreatic ducts. Indirect life cycle with psocid louse. Generally no clinical signs, but liver damage can occur.

Describe abdominal/visceral cysticerocosis.

AKA bladder worms. Occasional finding at slaughter. Affects liver and peritoneal cavity. Larval form of Taenia hydatigena, the dog tapeworm. Forms migratory tracts through the liver and develops into small, fluid-filled bladders. Usually asymptomatic.

Describe echinococcosis.

AKA hydatid disease Larval form of Echinococcus granulosis, the canid tapeworm. Cystic structures in liver or lungs develop and can rupture, forming new cysts. Often asymptomatic. Prevent via minimizing exposure to canine-feces contaminated feeds.

How do cysticercosis and echinococcosis differ?

Cysticercosis - Larval form of dog tapeworm (Taenia hydatigena) Echinococcosis - Larval form of canid tapeworm (Echinococcosis granulosis)

What are the three common species of trematodes in the US?

Fasciola hepatica, Fascioloides magna, and Dicrocoelium dendriticum

What is the intermediate host of trematodes? Where do trematodes live? How do they cause disease?

Freshwater snail is intermediate host Live in bile duct and cause liver damage, with disease related to migration of immature flukes.

What are the economically important forms of trematode infections seen in cattle and sheep?

Chronic - Rarely fatal in cattle, often fatal in sheep. Subacute or acute - Primarily in sheep and fatal In conjunction with black disease

What is the genus and species of the New World Screwworm? Describe the condition.

Cochliomyia hominivorax. Found in SW US. Lays eggs near open wound which become increasingly large and malodorous with brown discharge. Adults male once, lay eggs, then diet. With eggs cycling through larvae to adult lifecycle again. Reportable disease.

What are nasal bots? Describe the condition.

Larvae of Oestrus ovis. Fly deposits eggs around sheep nostrils. Eggs hatch, larvae migrate to nasal cavity and sinuses. After 2-10 months, larvae mature and travel to nasal cavity where they are sneezed out. Larvae penetrate soil, pupate, and emerge as bot flies 1-1.5 months later. Signs: Stamping, snorting, and rubbing nose. Control with ivermectin in early fall.

What are sheep keds?

Melophagus ovinus. Flat, brown, blood-sucking wingless flies. Live their full 5-6 week life cycle on the sheep.

What species of dermatophytosis are found in ruminants?

Trichophyton mentagrophytes, T. verrucosum, Microsporum canis, and M. gypseum

Describe mites in ruminants in the US.

Rare. Sarcoptes, Psoroptes, and Psorergates reportable. Can also be impacted by Chorioptes (round) and Demodex.

Describe lice in ruminants.

Mallophagia and Anaplura. Produce a seasonal dermatitis, pruritus, and potentially anemia in young animals.

What diseases are ticks vectors for?

Anaplasma, Babesia, and Q fever.