Exam II - Eucoccidiorida

Question 1

Which parasitic group does Eimeria leukarti fall into?

Answer 1

Protozoan

Question 2

Describe the Eimeria leukarti oocyst

Answer 2

very large, 80 x 60 um, with a thick shell and distinct micropyle. The shell can come off

Question 3

What is/are the host(s) for Eimeria leukarti?

Answer 3

all equids

Question 4

What are the three phases in the Eimeria leukarti life cycle? What is the PPP for the 3 phases?

Answer 4

1. Sporulation
2. Asexual reproduction: infection & schizogony
3. sexual reproduction: gametogony and oocyst formation

PPP is 15 days

Question 5

What is/are the site(s) of infection for Eimeria leukarti?

Answer 5

small intestine

Question 6

Describe any pathogenesis associated with Eimeria leukarti

Answer 6

inflammatory changes in mucosa, disruption of villous architecture

Question 7

Describe any clinical signs associated with Eimeria leukarti. Who is most susceptible?

Answer 7

Intermittent diarrhea. Foals are most susceptible.

Question 8

How would you diagnose Eimeria leukarti?

Answer 8

Hard to diagnose because eggs are heavy. Sugar flotation of sedimentation methods are used

Question 9

Treatment & prevention options for Eimeria leukarti?

Answer 9

Antiprotozoals and supportive therapy

Question 10

What is the common name of the disease caused by Sarcocystis neurona?

Answer 10

Equine protozoal myeloencephalitis (EPM)

Question 11

What is/are the host(s) for Sarcocystis neurona?

Answer 11

Definitive host is opossum

Intermediate hosts are cats, striped skunks, raccoons, etc…

Accidental (aberrant) host is horse

Question 12

The Sarcocystis neurona life cycle includes ___________ in the definitive host and ____________ in the intermediate host

Answer 12

The Sarcocystis neurona life cycle includes gametogony in the definitive host and schizogony in the intermediate host

Question 13

In the normal **Sarcocystis neurona life cycle, where would you find bradyzoites?

Answer 13

muscle tissue

Question 14

Where do schizonts develop in the accidental **Sarcocystis neurona life cycle?

Answer 14

Schizonts develop in the horse’s neurons, NOT in muscle cells

Question 15

Describe any pathogenesis in the final host for Sarcocystis neurona

Answer 15

non-pathogenic

Question 16

Describe any pathogenesis in the intermediate host for Sarcocystis neurona

Answer 16

pathogenic effect due to 2nd stage scchizogony in vascular endothelium

Question 17

Describe any pathogenesis in the accidental host for Sarcocystis neurona

Answer 17

pathogenic due to 3^rd stage schizogony in nervous tissue rather than muscle

Question 18

Describe any clinical signs in horses as a result of Sarcocystis neurona

Answer 18

• Progressively debilitating disease affecting the CNS, brain, brainstem, and spinal cord
  
  • Unusual or atypical lameness, or seizures
  • Difficulty with standing, walking, or swallowing
  • May progress very rapidly

Question 19

What is the most commonly diagnosed infectious equine neurologic disease in America?

Answer 19

Equine Protozoal Myeloencephalitis (EPM)

Question 20

How would you diagnose Sarcocystis neurona in a horse before death?

Answer 20

clinical signs, western blotting, PCR of cerebral spinal fluid

Question 21

Describe treatment & prevention options for Sarcocystis neurona

Answer 21

Opossum control is CRITICAL. Prevent opossums from defecating where horses are fed.

Anti-protozoals can rid horse of Sarcocystis neurona organisms, but CNS damage may remain