Parasites

Question 1

Protozoa in muscle

Answer 1

Sarcocystis spp
Hepatozoon americanum
Toxoplasma gondii

Question 2

Helminths in muscle

Answer 2

Ascarids, ancylostoma
Trichinella
Pork and beef tape worms of people

Question 3

Sarcocystis spp prevalence

Answer 3

Common in muscle of many animals (IH)
Many species, strong host specificity
Nonpathogenic, rare for clinical myositits to present

Question 4

Hepatozoon americanum

Answer 4

Tick born parasite
Dog (IH) infected by ingesting tick or paratenic host

Question 5

Presence of Hepatozoon americanum

Answer 5

Enter marchrophages in muscles
Onion skin cell “mucopolysaccharide”
Intense local Pyogranulomatous inflammation and systemic disease, severe joint pain

Question 6

Trichinella

Answer 6

Ingestion of muscle containing encysted larvae (don’t produce eggs)
Invade small bowel mucosa (4wks)
Life cycle of parasite can be completed in just one host

Question 7

Eye worm

Answer 7

Thelazia spp - eye worm
Transmitted by flies
Different species in LA and SA
Conjunctival pouches/ducts
Treatment is removal

Question 8

Parasites and eyes

Answer 8

Parasites found from migrating aberrantly
Cuterebra
Dirofilaria
Toxocara and other ascarids
Toxoplasma (from disseminated infection)

Question 9

Parasites of CNS - SA

Answer 9

Cuterebra - common, uncommon as CNS
Toxoplasma gondii - common, uncommon as CNS
Neospora caninum - uncommon for k9 disease

Question 10

Parasites of CNS - LA

Answer 10

PT - frequent
Sarcocystis neurona - common
Neospora hughesi- uncommon

Question 11

Cuterebra spp

Answer 11

SubQ cyst on head/neck with bot
Sometimes in nasal passage - can migrate to CNS
Causes Feline ischemic encephalopathy (FIE)

Question 12

Signs of FIE

Answer 12

Depression, blindness, acute death
Difficult to diagnose

Question 13

Toxoplasma gondii

Answer 13

Sexual repro only in Felid GIT
Oocyst live long in enviro
High rates of seropositivity in many animal species
Disseminated infection can occur in any warm blooded animal

Question 14

Disease of toxoplasma

Answer 14

Disease produced by XX of tachyzoites in cells
^ tachy in nerve cells and eye can produce lesions and ophthalmic/NSD
Could be primary or recrudescence of infection
Immunosuppresion = conversion of Brady to tachy

Question 15

Toxoplasma in cats

Answer 15

Almost all infections are asymptomatic
Systemic is uncommon
Dyspnea, icterus and ocular lesions
Encephalitis can occur but is uncommon

Question 16

Diagnosing toxoplasma in cats

Answer 16

PCR - aqueous humor, CSF
Serology - IgM titers high with acute infection but can persist for 18 months
Rising IgG in paired titer over 2-3 wks = acute
Treatment with clindamycin is common

Question 17

Toxoplasma in dogs

Answer 17

Rare - can develop in puppies or dogs w distemper

Question 18

Toxoplasma in wildlife

Answer 18

Toxoplasma, Sarcocystis implicated in death of marine mammals like sea otters

Question 19

Neospora caninum

Answer 19

Asymptomatic in dogs
Uncommon cause of polyradiculoneuritis - myositis
Puppies and young dogs
Ataxia, ascending paralysis, muscle atrophy, spastic hyperextension

Question 20

Parelaphostrongylus tenuis (PT)

Answer 20

Meningeal worm
Metastrongyle parasite - needs IH
Adults in subarachnoid space & females release eggs
L1 in venous sinuses, carried in blood stream to lungs
L1 in airways, coughed, then swallowed
L1 environment ingested by snail or slug
Infective stage @1 month

Question 21

PT in deer

Answer 21

Deer ingest infective larvae
Migrate out of GIT and into CNS
Enter dorsal horn of SC and migrate to brain via dorsal nerve roots
PPP = 3 months

Question 22

PT susceptible

Answer 22

Camelids are most susceptible
Sheep & goats
Moose, elk, fallow deer, big horn sheep
Rare in cattle & EQ