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79 Cards in this Set

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Name 6 genera of Intestinal Apicomplexa
1. Cryptosporidium
2. Eimeria
3. Isospora (Cystoisospora)
4. Neospora?
5. Toxoplasma
6. Sarcocystis?
Monoxenous means?
Gve example of monoxenous parasite (in Intestinal Apicomplexa):
1 host, host specific
The species usually strictly host specific, using only a single host species e.g. Eimeria and Isospora (Cystoisospora); but sometimes will infect other host undergoing only asexual reproduction?
Eimeria has how many sporocysts? how many sporozoites in each sporocyst?
4 beers each for 2 dollars

4 sporocysts each containing 2 sporozoites

(pic shows Eimera's reptilian isolet)
Cystoisospora has how many sporozoites?
2 sporocysts each containing 4 sporozoites

2 beers each for 4 dollars
Cystoisospora more expensive...
T or F: Merozoites can contain thousands of Schizonts
False: Formation of Schizonts (which contain thousands of merozoites)
What protozoan parasite associated with BOVINE Coccidiosis?
(E. bovis , E. zuernii )
What are symptom of Winter Coccidiosis ?
Bloody diarrhea, tenesmus (straining). Rectal prolapses may occur. Secondary bact. enteritis and pneumonia is common sequelae.
Most common EIMERIA spp.
E. bovis
Worldwide distribution; estimated to cost > $70 million annually in production losses. Extending calving due to coccidiosis would cost $60-$70.
E. zuernii
Eimeria nonpathogenic in what animals?
Nonpathogenic species in horses & pigs
Eimeria Very important pathogen in what spp.?
cattle & poultry industries.
Eimeria clinical signs usually in calves of what age?
usually appears in 4 wk-old calves
What is the only species of enteric coccidia reported from N. American horses, oocysts very large with thick dark brown wall, appears to be prevalent and relatively harmless?
only E. leukarti - mostly harmless, large oocysts
What is the most important species involved in coccidiosis in pigs?
I. suis
What is the causative agent of avian coccidia, it is most severe in young chicks, causes enlarged inflammed cecae and bloody cecal contents, diarrhea, reduced weight gain and egg producction?
E. tenelia
If cow has recovered from Eimeria, can it be reinfected?
No, unless immune suppressed e.g. via stress
Lamma & alpacca Eimeria spp.?
E. macusaniensis
How do you diagnose coccidia?
emonstration of oocysts on fecal flotation
E. macusaniensis symptoms
Severely affected animals had signs of lethargy, weight loss, anorexia and diarrhea. Also evidence of: circ. shock, protein loss, renal insuff., bile stasis and hepatic lipidosis
In rabbits, Liver (E. stiedai) is more important than the intestinal
CYSTOISOSPORA have how many sporozoites?
Sporulated oocysts have 2 sporocysts, each with 4 sporozoites.
(2 beers for 4 dollars
Species of isospora in dogs
Four species of Isospora in dogs
Isospora canis is the largest oocyst (36 X 30 µm). Isospora ohioensis, I. neorivolta, and I. burrowsi
isospora found where in dog?:?
All inhabit the small or large intestine
Hypozoite – occur in __?
Hypozoite – occur in tissues of paratenic hosts
What is recommended for all calves aged less than 3 weeks of age and newborns, calves that recieved this were significantly less likely to shed cryptosporidium oocysts?
halofuginone lactate (halocur)
1. extraintestinal stages (hypnozoite = 1 sporozoite) occur in the tissues of paratenic hosts (mice, rats, hamsters, opossum).
2. extraintestinal stages occur in the tissues of the dog, cat and humans (I. belli).
how is life cycle of sarcocystis unique?
asexual stage in intermediate host (prey) and sexual stage is in definitive host
Neospora is taxonomically and genetically related to ?
What is more likely to cross placental barrier?
Neospora caninum is easily mistaken for Toxoplasma;

but Neospora more likely to cross placental barrier
What is the definitive host of Neospora caninum? What are the intermediate hosts? What is the most common host?
Dogs are the definitive host of Neospora caninum. Intermediate hosts are herbivores, especially cows.
Most of Neospora related abortions happen in what term?
mid to late term abortions
(in bovine btw. 4-8 mo. of gestation)
Which cows more likely to abort due Neospora infection?
A. asymptomatic cow with congenital infection
B. cow infected by ingesting oocysts (horizontal transmission)
A. Although may be asymptomatic with congenital infection, more like to abort!
~Somehow Neospora maintains low grade infection which becomes reactivated upon pregancy, crossing placental barrier with ease.
Is Neospora zoonotic?
unknown, although antibodies found against parasite, no parasite or clinical signs detected
How might dog get Neospora infection horizontally (if not congenital infection)?
Eating a placenta or aborted fetus of dairy cow
What possible clinical signs / symptoms of Neospora in puppy? (3)
CNS signs, dermatitis, pneumonia
What possible clinical signs / symptoms of Neospora in older animal? (4)
Older dogs
Neural, myocarditis, generalized disease, myositis, dermatitis

Dermal Neosporosis more common in older dogs, get ulcers
Best way to diagnose neonate calf?
Get serum, preferably pre-colostrum, before it has gotten antibodies from mother (check this)
How might dairy cow get infected with Neoplasma horizontally (if not congenital infection)?
Dogs can pass oocysts if defecate on hay etc, although do not shed a lot Neospora oocysts and difficult to detect
What tissue of aborted fetus might look to detect Neospora cysts/tachyzoites?
Brain, heart, occular musc. of eye, maybe liver
(NOT sk.muscle like Sarcocysta)
Neospora caninum cysts are (smaller OR bigger) than T. gondii cysts?
Neospora are smaller
Equine protozoal myeloencephalitis is caused by what parasite? Sign include lameness, ataxia, excess sweating, and loss of reflex also occur.
Sarcocystis neurona.
Identify this parasite. Cats are only def. host; any mammal (even cats) can be intermediate host and only pathogenic in IH.
Toxoplasma gondii
Congenitally infected pups may exhibit CNS signs, hind limb paralysis. Hyperextension of the hind limbs. What parasite?
Neonates with NEOSPORA infection may show CNS signs described here.
Are horses definitive host for Sarcocystis?
No, The horse is dead-end (aberrant) host.
Zoonotic apicomplexa?
Toxoplasma (cats are true definitive host), Sarcocystis, Cryptosporidium Parvum
Horse Muscle
Poultry Feces
Ruminant Feces
What species SARCOCYSTIS has opossum as definitive host?
S. neurona
What are intermediate host for S. neurona? (6)
many IH: armadillo, skunk, raccoon, sea otter, cat,

horse & marine mammals! serves as a dead end host (not true IH)
Worldwide Distribution
Obligatory 2 host / Predator-Prey Life Cycle (canine & feline)
Regional Prevalences:
High in ruminants, swine & horses
* Predator-Prey Life Cycle
SARCOCYSTIS can cause what in horse?
Equine Protozoal Myeloencephalitis (EPM)
# 1 Cause of neurological signs in horses.
T or F: S. neurona is of much importance in equine pathology
True: horse is not true intermediate, b/c dead end host
More than 60% cases of Equine Protozoal Myeloencephalitis (EPM) (sarcocystis) seen in what age group?
60% of the cases are in > 4-yr-olds
but ages range from 2 mo → 19 yr-old
Definitive host for Sarco. cruzi

Intermediate host for "
canine, coyote, red fox, raccoon, wolf
~IH is cattlecattle
(EPM) (sarcocystis) seen mostly in what horse breeds? (3)
Thoroughbreds, Standardbreds, and Quarter Horses affected most often.
How does predator become infected with Sarcocystis ?
predator becomes infected when ingest "sarcocyst" in muscle (cardiac or sk.) tisssue of prey (IH)
Asexual phase of Sarcocystis is in DH or IH?
intermediate host
(in muscle sarcocyst have brady zoites = slowly diving merozoites)
Species of sarcocystis which has human as DH? What are IH?
sarcocystis hominis (IH is cattle)
sarco.suihominis (IH is pig)
Definitive host for Sarco. cruzi, S.equicanis, S.tenella, S.fayeri, S.miescheriana?
canine, coyote, red fox, raccoon, wolf
What is IH for S. tenella (in wild dogs, raccon)?
S. tenella IH is sheep
~DH in wild dogs, raccon
Most specific and sensitive test for DIAGNOSIS: EPM? (2)
(Equine Protozoal Myeloencephalitis )
Western blot (and IFAT) to detect anti-S. neurona antibodies in CSF (NOT serum), because guess specific aB can cross BBB?
Differential Diagnosis of EPM (7)
Sarcocystis spp.
Equine Herpes
Head or spine trauma
Cervical stenotic myelopathy
Wobbler’s syndrome
Symptoms of EPM
Variable; asymmetric posterior ataxia, weakness, proprioceptive deficits, muscle atrophy and a wide variety of cranial nerve signs. Severity is directly related to the number of sporocysts ingested.
Very sensitive and specific for the detection of S. neurona antigen in histopathology prepared tissue samples (e.g., brain and spinal cord)?
Avidin-Biotin Immunohistochemical Staining (immunohistochemisty)
3 ways cats can contract Toxoplasma?
Which leads to shortest PPP?
ingest cyst, oocyst, or tachyzoite

*PPP is 3-10 days for TISSUE CYST -induced infections (occurs in 97% of cats that ingest tissue cysts). Ingesting sporulated T. gondii oocysts or tachyzoites results in oocyst-excreting infection in only 16-20% of cats.
TOXOPLASMA gondii - DH ?

Does sexual or asexual reprod. occur in cat?

Sexual development: in cat takes place in what tissue?

Asexual development?
Sex. dev. : occurs in intestinal epithelium

Asexual development: Intestinal phase (Merozoites).
What is Extraintestinal phase of toxoplasma?
Extraintestinal phase - Tachyzoites are rapidly-dividing tissue stages. Usually found in the liver, lungs, spleen, or lymph nodes.
T or F:Toxoplasma tachyzoites can cross the placental barrier (transplacental transmission).
Toxoplasma Bradyzoites (in cysts) are the slowly dividing tissue stages that are usually found in the ?? (tissues)
Bradyzoites (in cysts) are the slowly dividing tissue stages that are usually found in the brain, heart, skeletal muscle and eye.
Facultative intermediate hosts: for toxoplasma?
Facultative intermediate hosts: Wide range of vertebrates/birds.
Infective Stages for toxoplasma?
Sporulated oocysts (10 µm) – only domestic and wild felids shed oocysts
Symptoms of toxoplasma in human infections ?
Most human infections are ASYMPTOMATIC; but can have acquired and re-activated toxoplasmosis
if immunocompr. Fever, malaise, lymphadenopathy, encephalitis, myocarditis, pneumonitis and retinochoroiditis.
Congenital toxoplasmosis leads to ? (5)
Retinochoroiditis, intra-cerebral calcification, hydrocephalus, convulsions and death.
Immunity to toxoplasmosis?
Intestinal immunity is NOT life long.
Immunosuppression with high doses of corticosteroids will cause chronically infected cats to re-excrete T. gondii oocysts.
Cats that have previously recovered from a T. gondii infection will re-excrete T. gondii oocysts if they get a primary ____.
I. felis infection
T or F: Cats that have I. felis followed by T. gondii inf. will re-excrete T. gondii oocysts if challenged with I felis.
False; dev. strong immunity to T. gondii NOT re-excrete it if have I.felis first!
Toxoplasmosis in cattle? sheep?
RARE; ; usually asymptomatic in cattle

Major cause of abortion; focal placentitis. in sheep
A sheep has aborted due Toxoplasma inf.; could you do fecal float to diagnose?
NO, only in cat!