Parasites Flashcards
Protozoa in muscle
Sarcocystis spp
Hepatozoon americanum
Toxoplasma gondii
Helminths in muscle
Ascarids, ancylostoma
Trichinella
Pork and beef tape worms of people
Sarcocystis spp prevalence
Common in muscle of many animals (IH)
Many species, strong host specificity
Nonpathogenic, rare for clinical myositits to present
Hepatozoon americanum
Tick born parasite
Dog (IH) infected by ingesting tick or paratenic host
Presence of Hepatozoon americanum
Enter marchrophages in muscles
Onion skin cell “mucopolysaccharide”
Intense local Pyogranulomatous inflammation and systemic disease, severe joint pain
Trichinella
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
Eye worm
Thelazia spp - eye worm
Transmitted by flies
Different species in LA and SA
Conjunctival pouches/ducts
Treatment is removal
Parasites and eyes
Parasites found from migrating aberrantly
Cuterebra
Dirofilaria
Toxocara and other ascarids
Toxoplasma (from disseminated infection)
Parasites of CNS - SA
Cuterebra - common, uncommon as CNS
Toxoplasma gondii - common, uncommon as CNS
Neospora caninum - uncommon for k9 disease
Parasites of CNS - LA
PT - frequent
Sarcocystis neurona - common
Neospora hughesi- uncommon
Cuterebra spp
SubQ cyst on head/neck with bot
Sometimes in nasal passage - can migrate to CNS
Causes Feline ischemic encephalopathy (FIE)
Signs of FIE
Depression, blindness, acute death
Difficult to diagnose
Toxoplasma gondii
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
Disease of toxoplasma
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
Toxoplasma in cats
Almost all infections are asymptomatic
Systemic is uncommon
Dyspnea, icterus and ocular lesions
Encephalitis can occur but is uncommon
Diagnosing toxoplasma in cats
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
Toxoplasma in dogs
Rare - can develop in puppies or dogs w distemper
Toxoplasma in wildlife
Toxoplasma, Sarcocystis implicated in death of marine mammals like sea otters
Neospora caninum
Asymptomatic in dogs
Uncommon cause of polyradiculoneuritis - myositis
Puppies and young dogs
Ataxia, ascending paralysis, muscle atrophy, spastic hyperextension
Parelaphostrongylus tenuis (PT)
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
PT in deer
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
PT susceptible
Camelids are most susceptible
Sheep & goats
Moose, elk, fallow deer, big horn sheep
Rare in cattle & EQ
