Exam II - Phylum Apicomplexa Flashcards
What is the common name for Cystoisospora canis?
Coccidia
What is/are the final host(s) for Cystoisospora canis?
Dogs.
What is/are the paratenic host(s) for Cystoisospora canis?
rodents
How would you identify Cystoisospora canis?
It is the largest species of several in the dog (50 um).
Unsporulated oocysts are a single cell or sporont.
Describe the appearance of the Cystoisospora canis sporulated oocyst.
Sporulated oocysts spherical, 2 sporocysts each with 4 sporozoites, oval, largest species 50 um.
What are the 3 phases of the Cystoisospora canis life cycle?
- Sporulation
- infection & shizogony (or merogony)
- Gametogony & oocyst formation
Describe the sporulation phase in Cystoisospora canis
Unsporulated oocysts pass in feces. Sporulation takes place outside host. Sporulated oocyst contains 2 sporocysts with 4 sporozoites. This is the infective stage.
What is the infective stage for Cystoisospora canis?
sporulated oocyst
Describe the infection & schizogony phase for Cystoisospora canis
Definitive host becomes infected by ingesting a sporulated oocyst. Each sporocyst releases 4 sporozoites. A paratenic host can ingest this oocyst. When the paratenic host & its cyst are ingested by the final host, sporozoites are released form the cyst in the final host.
Each sporozoite gives rise to a shizont containing merozoites. Merozoites rupture out of the small intestinal cell, enter another cell, from a 2nd & 3rd generation shizont.
Describe the gametogony & oocyst formation phase for Cystoisospora canis
Merozoites give rise to male & female gametocytes. The macrogametocytes are female, remain unicellular, but increase in size to fill the parasitized cell. The are distinguishable by the single large nucleus.
The male microgametocytes undergo repeated division to form a large number of flagelated uninucleate organisms, the microgametes. This is the only time coccidia have organs of locomotion.
Fusion & fertilization or micro- and macrogametes take place and a cyst wall forms which results in a zygote, now an oocyst.
This oocyst ruptures out of its cell, and passes as an unsporulated oocyst in the feces of the host. PPP is 4-11 days (depending on species)
What is/are the site(s) of infection for Cystoisospora canis?
small intestine
Describe any pathogenesis associated with Cystoisospora canis
small intestinal cells are destroyed, leading to enteritis.
Describe any clinical signs associated with Cystoisospora canis
most species are asymptomatic. Young dogs are more susceptible and will show clinical signs. Diarrhea can be watery, severe, profuse, and bloody.
How would you diagnose Cystoisospora canis?
oocyst in feces. Smaller than ascarid eggs (80-100 um) and larger than Sarcocystis eggs (18 um)
Describe any treatment & prevention options for Cystoisospora canis
Management is critical. Antiprotozoal remedies are available also.
What is/are the final host(s) for Toxoplasma gondii?
cats
What is/are the intermediate host(s) for Toxoplasma gondii?
humans, dogs, livestock, and birds
Describe the appearance of the Toxoplasma gondii oocyst
Oocyst found in feces of cat, small, 12 um. When sporulated in 1-5 days, oocysts contain 2 sporocysts, each with 4 sporozoites
Describe the Toxoplasma gondii life cycle
Large numbers of unsporulated oocysts are shed in cat poop. Oocysts sporulated within 1-5 days in the environment and become infective.
Intermediate hosts become infected after ingesting soil, water, or plant material contaminated with oocysts.
Oocysts transform into tachyzoites shortly after ingestion. These tachyzoites develop into bradyzoites (tissue cyst form).
Cats are infected when they eat the intermediate host with the cyst. The cyst wall is digested in the cat’s stomach and the liberated bradyzoites start a cycle of development to produce oocysts in 3-10 days in the intestinal epithelium.
The freed sporozoites rapidly penetrate the intestinal wall and spread via the blood. The invasive & proliferative stage is the tachyzoite.
What is the invasive & proliferative stage of the Toxoplasma gondii life cycle?
The tachyzoite is the invasive & proliferative stage
How are cats infected with Toxoplasma gondii?
eating infected rodents or directly ingesting the oocyst
What is/are the site(s) of infection for Toxoplasma gondii?
Intestinal & extraintestinal tissues in both hosts
describe any pathogenesis associated with Toxoplasma gondii
most animals are asymptomatic. Clinical disease in cats occurs and depends on the organs involved & the extent of cells infected. Acute toxoplasmosis.Severe seen with FIV
How would you diagnose Toxoplasma gondii?
oocysts in cat feces. Serological tests, modified direct agglutination test, ELISA & IFA
Cats develop immunity after initial infection & shed only once in a lifetime (four 1-2 weeks)
Describe some treatment & prevention options for Toxoplasma gondii
- humans should avoid contact with cat poop
- humans should avoid undercooked meat from intermediate host
- pregnant women should avoid contact with all sources of oocysts
- nonsulfonamides and sulfonamides are used
What is/are the final host(s) for Sarcocystis spp?
final hosts are dogs, cats, humans, carnivores, and birds
What is/are the intermediate host(s) for Sarcocystis spp?
cattle, herbivores, omnivores, birds
These are individual Sarcocystis spp sporocysts
Enjoy that
List the phases of the life cycle of Sarcocystis spp
The life cycle includes gametogony in the final host, and schizogony & sarcocyst formation in the intermediate host
How is the final host infected with Sarcocystis spp?
Infection is by ingestion of mature sarcocysts with bradyzoites in the muscle of the intermediate host
How is the intermediate host infected with Sarcocystis spp?
Infection is by ingestion of the sporocysts from an infected final host, followed by at least 3 asexual generations
What is the PPP for Sarcocystis spp in carnivores?
1-2 weeks
How long is the patent period for Sarcocystis spp?
1 week to several months
What is/are the site(s) of infection for Sarcocystis spp?
muscles in intermediate hosts. Sporocysts in GI tract of final host
Describe some clinical signs in each host for Sarcocystis spp
No illness in final host, but fatal disease in intermediate herbivore host. Abortion may result.
How would you diagnose Sarcocystis spp?
Sporocysts in final hosts. Positive diagnosis based on badyzoites in muscle tissue of the intermediate host
Describe treatment and prevention options for Sarcocystis spp?
Avoid raw meat & prevent fecal contamination
What is/are the host(s) for Hepatozoon spp?
Dogs.
What is/are the site(s) of infection for Hepatozoon spp?
White blood cells
What are some clinical signs associated with various species of Hepatozoon spp?
- H. canis* - subclinical infection
- H. americanum* - severe disease; joint pain, myositis
How would you diagnose Hepatozoon spp?
Parasites in peripheral blood; examination of muscle tissue at biopsy or necropsy
Describe treatment & prevention options for Hepatozoon spp
No satisfactory treatment :(
tick control
