Protozoal and fungal disease of CNS

seraclues's version from 2015-09-06 03:06

Equine Protozoal Myeloencephalitis (EPM)

Question Answer
What is the causative agent behind Equine Protozoal Myeloencephalitis (EPM)?Sarcocystis neurona
When are you most likely to see EPM?prevalence is low, but most common in summer and fall
What are the clinical signs of EPM?ataxia, limb weakenss, lameness and sometimes seizures
What are the gross lesions present with EPM?You only see them when severe, but multifocal acute, hemorrhage to discrete multifocal grey to dark yellow areas


Question Answer
What is the causative agent behind Neosporosis?Apicomplexan protozoa
What does Neosporosis causes in cows and dogs?bovine abotion and neuromuscular disease in dogs
How is Neospora contracted?Dogs eat contaminated meat and crap out oocysts. Cows eat food, water or soil contaminted with the oocycst. But also transplcental
What is the MAIN route of contraction of neosporosis in cows?Transplacental
How does neosporosis affect pups when infected en utero?muscle atrophy, dysphagia, heart failure
What are the clincial signs of Neosporosis in adult dogs?ataxia, head tilt, hind limb paresis, rigidity, progressive paralysis

Cryptococcus neoformins

Question Answer
Describe the inflammatory reponse caused by Crytpococcus neoformas fungi?Granulomatous or pyogranulomatous
Which species are most susceptible to cryptococcus neoformans fungi?Cats, dogs and horses
How does cryptococcus neoformans enter the CNS?Through the cribiform plate following nasal or sinus infections, or via leukocyte trafficking if pulmonary infection.
What does cryptococcus neoformans look like histologically, in the brain?multiple, small cysts
which breeds of dog are predisposed to idiopathic inflammatory disease?young to middle-aged small breeds (terriers and toy breeds).

Polioencephalomalacia of ruminants (PEM)

Question Answer
What causes Polioencephalomalacia of ruminants (PEM)?iduced thiamine deficiency, or excess dietary sulphur, suphates and sulphites.
What are the gross lesions of Polioencephalomalacia?edema nd laminar necrosis
What are the clinical signs of polioencephalmalacia?blidness, twitches, convulsions, nustagmus and head pressing
What are the histological lesions of polioencephalomalacia?acute neuronal necrosis in a laminal pattern

Mycotoxic leukoencephalomalacia of horses

Question Answer
What is the cause of mycotoxic leukoencephalomalacia of horses?Occurs in horses fed moldy corn for over a month
What is the causative agent of mycotoxic leukoencephalomalacia in horses?Mycotoxin Fumonisin-B1 (produced by Fusarium certicilloides or F.proliferatum, whci grow on corn in warm, moist conditions)
What are the clinical signs of leukoencephalomalacia in horses?sudden onset dorsiwness, impaired vision, partial or complete pharyngeal paralysis, weakness, staggering, circling

Hepatic Encephalopathy (HE)

Question Answer
What is the cause of Hepatic Encephalopath (HE)?High urea (which is neurotoxic); eg urea cycle enxzyme deficiency or shunting of portal blood.
What ar ethe CNS changes with Hepatic Encephalopathy?there are no gross CNS changes. on Histo, you see polymicrocavitation of myelin at various levels.

Copper deficiency

Question Answer
Clinical swayback (copper deficiency) occurs in both congenital and delayed forms in lambs. Expain the difference Congenital is due to mums deficiency. Delayed (enzootic ataxia) is normal at birth but develop signs.
which species are prone to sway back (copper deficiency)?lambs, kids and piglets
What are the clinical signs of swayback (cooper deficiency)?Motor disturbances-staggering and ataxia. Congeital cases can be blind and unable to stand.
What is the cause of rye-grass staggersDue to lollitrems produced by the endophytic fungus Neotyphoidiium lolii.
What type of grass can cause rye-grass staggers?lolium perenne
What time of year are you most likely to see ryegrass staggers?summer and autumn, on dry, short pastures
What are the clinial signs associated wtih ryegrass staggers?fine head tremors and head nodding and weaving, stiff-legged, incoordinated gait
What are the microscopic changes seen with ryegrass staggers?enlargement of the proximal axons of some cerebellar purkinje fibres

Peripheral axonopathies of horses

Question Answer
What is the cause of Equine Laryngeal Hemiplegia?idiopathc degeneration of the left recurrent laryngeal nerve, so denervation atrophy of the intrinsic muscles of the left side of the larynx. So arytenoic cartilge and vocal fold can not adduct
What is the cause of Equine Suprascapular Neuropathy?Damage to, causing atrophy of the suprascapular nerve, which innervates the infrapinatus and supraspinatus muscles.
What is the cause of Equine stringhault?Sporadic forms are idiopathic. Enzootic forms may be due to eating false dandelion and flatweed
What lesions woudl you see with Equine Stringhalt?Distal axonopaty with Wallerian degeneration