Protozoa III & IV: Apicomplexa Eimeria, Isospora Flashcards
What is sporogony in the Apicomplexa generic life cycle?
Asexual reproduction; a single zygote produces infective sporozites
What is merogony (schizogony) in the Apicomplexa generic life cycle?
Asexual reproduction; sporozites undergo a rapid division to become meront stages containing numerous invasive merozoites
Several generations possible, depending on species
What is gametogony (gamogony) in the Apicomplexa generic life cycle?
Merozoites differentiate into gametes
What is fertilization in the Apicomplexa generic life cycle?
Gametes fuse to produce zygote
What is the Coccidian generic life cycle?
Zygote—sporogony—sporozoites—host cell invasion—merozites (which undergo merogony/schizogony)—Gamogony—gametes—fertilization— and the cycle begins again at zygote
What is the specificity of Eimeria spp.?
Host specific and site specific
What is the most common Eimeria spp. in cattle?
E. zuernii
Also, E. bovis
Is Eimeria infectious in a dog or cat?
No
Why could Eimeria be seen in the fecal float of a dog?
They eat poop
What are the pathogenic species of Eimeria?
E. bovis, E. zuernii (cattle)
E. tenella, E. maxima (chickens)
What are Eimeria oocysts like?
Unsporulated when released in feces
Where does sporogony occur for Eimeria?
In the environment
Describe the Eimeria sporulated oocyst?
Has 4 sporocsyts, each with 2 sporozoites
Describe the Eimeria life cycle
Ingested Sporozoites infect target cells Merogony Gametogony Gametes fuse- oocyst produced
What are factors that contribute to the pathology of Eimeria?
Host
Species
Site of infection
Challenge
What are general clinical signs of Eimeria?
Severe, watery diarrhea, dehydration
Bloody feces
Loss of weight/decreased weight gain
Lethargy/depression
When is damage done with Eimeria?
Once oocysts are present
What disease is E. zuernii associated with?
Nervous coccidiosis
What is the prepatent period of EImeria in cattle?
2-3 weeks
What are the pathogenic Eimeria species in sheep?
E. ahsata
E. ovina
E. ovinoidalis
How are the lesions from Eimeria diagnosed?
Direct smear
Lesion scoring
Histology
What is the fecal examination of Eimeria?
Sugar flotation, McMaster’s
If identifying oocyst, don’t refrigerate because it delays the sporulation process (48 hour process)
What are methods of control for Eimeria?
Anticoccidials: prophylactic treatment Live cocci vaccines (poultry) Environmental control (sanitation, litter management) Animal management (monitoring; mixed ages; prophylactic treatment programs)
Describe the direct life cycle of Isospora/Cystoisospora
Unsporulated oocysts shed in environment— sporogony— sporulated—oocysts
Describe the Isospora/Cystoisospora oocysts
2 dporocysts with 4 sporozites each
What are the target cells of Isospora?
Intestinal
What are the target cells of Cystoisospora?
Intestinal development if the definitive host ingests sporulated oocyst
Extraintestinal development if paratenic host ingests sporulated oocyst- monozoic tissue cyst form
What are the asexual stages of the Isospora/Cystoisospora direct life cycle?
Sporozoites invade host intestinal cell and undergo merogony Merozoites formed Invade new host cell Second generation of merozoites Invade new cells
What are the sexual stages of the Isospora/Cystoisospora direct life cycle?
Gametogony: Male/female gametes Fertilization Oocysts produced Passed in feces unsporulated
Describe the indirect life cycle of Cystoisospora
Insporulated oocysts shed in environment
Sporogony
Sprulated oocysts (2 sporocysts with 4 sporozoites each)
What does the definitive host ingest in the indirect life cycle of Cystoisospora?
Sporulated oocysts
What does the paratenic host ingest in the indirect life cycle of Cystoisospora?
Monozoic cysts, then sporozoites released, and infect intestinal cells
What are the asexual stages of the Cystoisospora indirect life cycle?
Sporozoites invade host intestinal cell undergo merogony Merozoites formed Invade new host cell Second generation of merozoites Invade new cells
What are the sexual stages of the Cystoisospora indirect life cycle?
Gametogony: Male/female gametes Fertilization Oocysts produced Passed in feces unsporulated
What is the PPP for Isospora/Cystoisospora?
At least 1 week
Describe Isospora suis
Neonatal porcine coccidiosis
Ubiquitous where pigs are farrowed in confinement
15-20% of swine diarrhea diagnostic cases in US
What is the PPP of Neonatal porcine coccidiosis/Isospora suis?
As short as 5 days, oocysts shed in 1-3 weeks
What are the clinical signs and pathology os Isospora suis?
Diarrhea Dehydration Lethargy Destruction of villus epithelium in SI Mortalities
What is the diarrhea caused by Isospora suis like?
Develops 7-14 days of age
Pasty yellow; becomes fluid after 2-3 days
How is the fecal oocyst of Isospora suis detected?
Fecal flotation
What are the control methods of Isospora suis?
Place sows on anticoccidial during third trimester
Steam clean facilites
Albon and other sulfonamides
Baycox
Describe Cystoisospora in dogs
Ubiquitous in young dogs
Host specific
What are the clinical signs of Cystoisospora in young dogs?
Diarrhea, dehydration, anorexia, weight loss
Asexual/sexual stage destroy intestinal cells
At what age is Isospora/Cystoisospora more pathogenic in cats?
4 weeks or younger
What are the diagnostics of Isospora/Cystoisospora in dogs and cats?
Fecal oocyst is detected by fecal flotation
Sporulation: 16 hours
What are the control methods of Isospora/Cystoisospora in dogs and cats?
Disencourage ingestion of paratenic hosts
Sanitation
Treat all animals
Anticoccidials
