23. sarcocystis

Question 1

Sarcocystis are —

Answer 1

GI parasites
coccidia
Apicomplexa
Protozoa

spread by fecal-oral

Question 2

lifecycle of sarcocystis

Answer 2

obligatory prey-predator(2 host) life cycle

DH will release sporocyst in feces, IH will eat sporocysts and cause cysts to form in the muscle

asexual in IH (prey herbivore)- might cause disease

sexual in DH (predator carnivore)- rare disease

Aberrant- horse- severe disease

Question 3

Sarcocystis go through asexual stages in —

Answer 3

intermediate host (prey)
might cause disease

Question 4

Sarcocystis go through sexual stages in —

Answer 4

definitive host (carnivore)
rare disease

Question 5

stages of Sarcocystis in DH to IH

Answer 5

oocyst will sporulate inside DH GI tract to form SPOROCYST

IH will eat sporocyst

will form sporozoite in SI
then Schizonts (asexual reproduction) in vasculature

then merozoites in blood and white blood cells

then form cysts( sarcocysts) in muscle that contain slow proliferating forms called bradyzoites

host dies and DH eat IH with cysts in muscle

Question 6

what type of host for sarcocystis usually are nonpathogenic and usually an incidental finding on post mortem

Answer 6

intermediate host ( prey- herbivore)

Question 7

sarcocystis in ruminants can cause

Answer 7

cause by damage to endothelial cells

Acute phase:
– Fever, anorexia, poor growth, anemia, emaciation, hair loss, abortion, death
– Edema, hemorrhage (petechiae, ecchymoses),
atrophy of fat sarcocysts

• Chronic phase:
  – Subclinical
  – Nonsuppurative myositis, degeneration of sarcocysts

Question 8

sarcocystis lifecycle in DH

Answer 8

DH eat IH with cysts in muscle

bradyzoites will undergo sexual reproduction and form oocysts that form spores that are pooped out and eaten by IH

Question 9

EPM

Answer 9

equine protozoal myeloencephalitis

caused by aberrant host sarcocystis

Question 10

what causes EPM

Answer 10

Sarcocystis neurona

Question 11

DH for Sarcocystis neurona

Answer 11

possum- found only in North and South America

causes EPM in horses

Question 12

signs of EPM

Answer 12

can cause almost any CNS signs

due to location of the lesion!

lower motor neuron- lameness and atrophy

UMN- spinal asymmetric ataxia

Brainstem- dysphagia, facial paralysis, vestibular disease

Question 13

3 common signs of Sarcocystis neurona

Answer 13

ataxia, atrophy and asymmetry

cause EMP in horses

Question 14

how to diagnose EPM

Answer 14

antibodies very common- from eaten possum poop

need to compare ratio of serum to CSF

need to rule out other diseases

presumptive diagnosis

Question 15

what lab test for EPM

Answer 15

SAG 2,4/3 elisa

ratio of serum to CSF antibodies

Question 16

why can antibodies be in CSF even if EPM not in CNS

Answer 16

natural diffusion of antibodies from blood to CSF

Question 17

treatment for EPM

Answer 17

anti-protozoal meds and anti inflammatory

60% improve, 15% return to normal

Question 18

Sarcocystis is a coccidian, —, protozoal parasite with a — life-cycle

Answer 18

apicomplexan
2-host (predator/prey)

Question 19

Sarcocystis disease is rare in —, usually mild/subclinical in —

Answer 19

definitive host (carnivore)

intermediate host
(herbivore)

Question 20

aberrant hosts of Sarcocystis causes

Answer 20

EPM
Equine protozoal myeloencephalitis

Question 21

— is the most important infectious equine neurologic (CNS) disease

Answer 21

EPM

Question 22

EPM definitive host

Answer 22

opossum

Sarcocystis neurona

Question 23

test for EPM

Answer 23

serum:CSF titer
ratio (SnSAG2, 4/3 ELISA)

Question 24

Sarcocystis in marine animals

Answer 24

aberrant host

Marine mammal protozoal encephalitis