VPAR 131 Lecture Notes on Protozoa

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Questions and Answers

At what age do puppies and kittens typically get infected with cystoisosporosis?

Between one and two weeks

Between three and eight weeks (correct)

After four months

Between nine and twelve weeks

What is the primary method of diagnosis for cystoisosporosis?

Blood test

Physical examination

Imaging techniques

Fecalysis for oocysts (correct)

What is the primary treatment for cystoisosporosis?

Toltrazuril and diclazuril (correct)

Oral sulfadimethoxine and ampicillin

Toltrazuril and metronidazole

Oral sulfonamide and trimethoprim-sulfonamide

What type of muscles are affected by Sarcocystis?

Striated and cardiac muscles Signup and view all the answers

What is the primary host of Sarcocystis?

Ruminants, pig, horse, rodents Signup and view all the answers

What forms dominate immature cysts of Sarcocystis?

Metrocytes Signup and view all the answers

What is the main difference between the life cycle of Family Sarcocystidae and Eimeriidae?

Type of hosts required for reproduction Signup and view all the answers

What is the typical final host (FH) of Family Sarcocystidae?

Carnivores Signup and view all the answers

Where can oocysts of Family Sarcocystidae sporulate?

Either within the final host or in the environment Signup and view all the answers

How many sporozoites are found in each sporocyst of Family Sarcocystidae?

Four Signup and view all the answers

What is the characteristic feature of the life cycle of Family Sarcocystidae?

Heteroxenous life cycle Signup and view all the answers

What is the main difference between the hosts of Family Sarcocystidae and Eimeriidae?

Type of hosts Signup and view all the answers

How many sporocysts are found in each oocyst of Family Sarcocystidae?

Two Signup and view all the answers

What is the typical intermediate host (IH) of Family Sarcocystidae?

Prey animals Signup and view all the answers

Where are oocysts produced and sporulated?

In the intestinal cells of the definitive host Signup and view all the answers

What is the stage of the parasite that is found in the tissues of the intermediate host?

Tachyzoites and bradyzoites Signup and view all the answers

Which of the following genera is characterized by the absence of Stieda bodies in the sporocyst?

Cystoisospora Signup and view all the answers

How can dogs and cats become infected with Cystoisospora?

By ingesting sporulated oocysts from the environment or through predation Signup and view all the answers

What is the typical outcome of Cystoisospora infection in animals?

Subclinical infection Signup and view all the answers

Which of the following animals are more susceptible to Cystoisospora infection?

Young animals Signup and view all the answers

What is the stage of the parasite that infects tissues and encysts in prey animals?

Sporozoites Signup and view all the answers

Which of the following species of Cystoisospora affects dogs?

C. canis Signup and view all the answers

What is the most pathogenic species of cruzi?

bovicanis Signup and view all the answers

Which of the following is a common clinical sign of cruzi infection in cows?

Reduced milk yield Signup and view all the answers

What is the characteristic of S.gigantea in sheep?

Produces rounded macroscopic sarcocysts in the esophagus and tongue Signup and view all the answers

What is the common clinical sign of S.tenella infection in lambs?

Fever Signup and view all the answers

Which of the following is a complication of heavy cruzi infection in calves?

Petechial hemorrhages Signup and view all the answers

What is the characteristic of Sarcocystis infection in sheep?

Causes anemia and fever Signup and view all the answers

What is the mode of infection of FH by Sarcocystis species?

Through predation Signup and view all the answers

Where does schizogony occur in the life cycle of Sarcocystis species?

In endothelial cells in small blood vessels Signup and view all the answers

What is the pathogenic effect of Sarcocystis infection in the FH?

It is usually non-pathogenic Signup and view all the answers

What is the role of tachyzoites and merozoites in the pathogenesis of Sarcocystis infection in the IH?

They are responsible for the pathogenic effects Signup and view all the answers

What is the significance of sarcocystin in Sarcocystis infection?

It is an endotoxin that may be present in intact sarcocysts Signup and view all the answers

What is the mode of transmission of Sarcocystis species from the IH to the FH?

Through the ingestion of sporocysts Signup and view all the answers

What is the significance of endothelial cells in the life cycle of Sarcocystis species?

They are involved in the schizogony stage Signup and view all the answers

What is the general pathogenicity of most Sarcocystis species?

Low pathogenicity Signup and view all the answers

Study Notes

Family Sarcocystidae

Heteroxenous life cycle, requiring one type of host for sexual reproduction and another for asexual reproduction
Final hosts (FH) are carnivores, while intermediate hosts (IH) are mostly prey animals
Oocysts may sporulate within the FH or in the environment
Each sporulated oocyst contains two sporocysts with four sporozoites each

Cystoisospora

Formerly under Isospora, but reclassified into a separate genus
Stieda bodies absent in the sporocyst
Dogs and cats can become infected by ingesting sporulated oocysts from the environment or through predation
Species affecting dogs: Cystoisospora canis, C.ohioensis, C.burrowsi, and C.neorivolta
Species affecting cats: C.felis and C.rivolta
Infection is usually subclinical, but can cause diarrhea, which may contain blood in severe cases
Young animals are more susceptible to infection
Diagnosis: fecalysis for oocysts; must allow sporulation for differentiation with Eimeria
Treatment: Toltrazuril and diclazuril are the drugs of choice

Sarcocystis

Sarcocysts containing bradyzoites form in striated and cardiac muscles, occasionally the brain of the IH
Two types of cysts: macrocyst and microcyst
Oocysts sporulate within FH like carnivores and man
Sporulated oocysts or sporocysts are passed in the feces
IH, e.g. ruminants, pig, horse, rodents, are infected by ingesting sporocysts
Sarcocysts are the infective form for the FH

Sarcocystis Life Cycle

FH gets infected by predation
Merozoites form sarcocysts in muscles
Schizogony occurs in endothelial cells in small blood vessels
Sexual reproduction occurs in the intestine of the FH, forming oocysts
Sporocysts are swallowed by the IH

Sarcocystis: Pathogenesis

Most Sarcocystis spp. are considered of low pathogenicity
Infection in FH is usually non-pathogenic
Pathogenic effects in the IH are due to tachyzoites and merozoites in endothelial cells
Intact sarcocysts do not appear pathogenic but may contain endotoxin known as sarcocystin
Sarcocystis of cattle: S.cruzi (bovicanis) is the most pathogenic species
Clinical signs include protracted fever, anemia, lymphadenopathy, anorexia, diarrhea, hypersalivation, weakness, hair loss around the eyes, and tail twitch
Reduced milk yield, abortion, and placentitis may be observed in cows
Heavy infection in calves may cause petechial hemorrhages and generalized lymphadenopathy

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Description

This quiz covers the general features of Family Sarcocystidae, including Cystoisospora, Sarcocystis, Toxoplasma, Neospora, and Besnoitia besnoiti. Topics are relevant to VPAR 131 lecture notes.