36 Questions
At what age do puppies and kittens typically get infected with cystoisosporosis?
Between three and eight weeks
What is the primary method of diagnosis for cystoisosporosis?
Fecalysis for oocysts
What is the primary treatment for cystoisosporosis?
Toltrazuril and diclazuril
What type of muscles are affected by Sarcocystis?
Striated and cardiac muscles
What is the primary host of Sarcocystis?
Ruminants, pig, horse, rodents
What forms dominate immature cysts of Sarcocystis?
Metrocytes
What is the main difference between the life cycle of Family Sarcocystidae and Eimeriidae?
Type of hosts required for reproduction
What is the typical final host (FH) of Family Sarcocystidae?
Carnivores
Where can oocysts of Family Sarcocystidae sporulate?
Either within the final host or in the environment
How many sporozoites are found in each sporocyst of Family Sarcocystidae?
Four
What is the characteristic feature of the life cycle of Family Sarcocystidae?
Heteroxenous life cycle
What is the main difference between the hosts of Family Sarcocystidae and Eimeriidae?
Type of hosts
How many sporocysts are found in each oocyst of Family Sarcocystidae?
Two
What is the typical intermediate host (IH) of Family Sarcocystidae?
Prey animals
Where are oocysts produced and sporulated?
In the intestinal cells of the definitive host
What is the stage of the parasite that is found in the tissues of the intermediate host?
Tachyzoites and bradyzoites
Which of the following genera is characterized by the absence of Stieda bodies in the sporocyst?
Cystoisospora
How can dogs and cats become infected with Cystoisospora?
By ingesting sporulated oocysts from the environment or through predation
What is the typical outcome of Cystoisospora infection in animals?
Subclinical infection
Which of the following animals are more susceptible to Cystoisospora infection?
Young animals
What is the stage of the parasite that infects tissues and encysts in prey animals?
Sporozoites
Which of the following species of Cystoisospora affects dogs?
C. canis
What is the most pathogenic species of cruzi?
bovicanis
Which of the following is a common clinical sign of cruzi infection in cows?
Reduced milk yield
What is the characteristic of S.gigantea in sheep?
Produces rounded macroscopic sarcocysts in the esophagus and tongue
What is the common clinical sign of S.tenella infection in lambs?
Fever
Which of the following is a complication of heavy cruzi infection in calves?
Petechial hemorrhages
What is the characteristic of Sarcocystis infection in sheep?
Causes anemia and fever
What is the mode of infection of FH by Sarcocystis species?
Through predation
Where does schizogony occur in the life cycle of Sarcocystis species?
In endothelial cells in small blood vessels
What is the pathogenic effect of Sarcocystis infection in the FH?
It is usually non-pathogenic
What is the role of tachyzoites and merozoites in the pathogenesis of Sarcocystis infection in the IH?
They are responsible for the pathogenic effects
What is the significance of sarcocystin in Sarcocystis infection?
It is an endotoxin that may be present in intact sarcocysts
What is the mode of transmission of Sarcocystis species from the IH to the FH?
Through the ingestion of sporocysts
What is the significance of endothelial cells in the life cycle of Sarcocystis species?
They are involved in the schizogony stage
What is the general pathogenicity of most Sarcocystis species?
Low pathogenicity
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
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.
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