Lecture 20 4/8/24

Question 1

What are the characteristics of prions?

Answer 1

-proteinaceous infectious particles
-“normal” prion is converted to a misfolded protein
-misfolded protein acts as a template to convert more misfolded proteins

Question 2

What do prions cause?

Answer 2

neurodegenerative disorders

Question 3

What are the characteristics of sporadic prion disease?

Answer 3

-“normal” brain protein will misfold and become a prion
-more common in older individuals

Question 4

What are the characteristics of familial prion disease?

Answer 4

-mutations in genes encoding prion protein facilitate conversion to misfolded state
-inherited

Question 5

What are the characteristics of transmitted prion disease?

Answer 5

-no alterations in the prion gene
-linked to consumption of contaminated foods or blood transfusions

Question 6

What are some of the famous human prion diseases?

Answer 6

-CJD (sporadic)
-vCJD/mad cow disease (transmitted)
-Gerstmann-Straussler-Scheinker syndrome (inherited)
-fatal familial insomnia (inherited)
-kuru (transmitted)

Question 7

What are the veterinary prion diseases of importance?

Answer 7

-bovine spongiform encephalopathy
-feline/mink spongiform encephalopathy
-scrapie
-chronic wasting disease

Question 8

What are the characteristics of bovine spongiform encephalopathy?

Answer 8

-disease of bovids
-has infected cats
-cause of vCJD
-classical form spreads via ingestion of infected CNS tissue
-ban on animal feeds including ruminant protein
-incubation period of 3-6 years
-atypical form is spontaneous; seen in older animals
-reportable

Question 9

What are the characteristics of feline/mink spongiform encephalopathy?

Answer 9

-attributed to ingestion of meat and bone from BSE-affected cattle
-prions accumulate in lymph nodes, spleen, and ileum in addition to CNS
-reportable

Question 10

What are the characteristics of scrapie?

Answer 10

-no known zoonotic events
-transmitted through contaminated food/pasture, inhalation of secretions/placental tissues/saliva, and/or secreted in milk/colostrum
-incubation period of 2-5 years

Question 11

What are the clinical signs of scrapie?

Answer 11

-lying down
-biting at feet
-rubbing backs against posts
-failure to thrive
-anorexia
-death due to emaciation

Question 12

What are the characteristics of scrapie eradication programs?

Answer 12

-selective breeding for resistance
-depopulation
-surveillance
-diagnostics via IHC on post-mortem specimens

Question 13

What should be done if scrapie is identified in a flock?

Answer 13

-remove genetically susceptible animals
-attempt live animal testing and remove test-positive animals
-clean/disinfect lambing facilities
-breed for genetic resistance
-employ embryo transfer and cesarean section
-segregating animals away from lambing

Question 14

What are the characteristics of CWD?

Answer 14

-seen in deer, elk, reindeer
-causes weight loss, stumbling, aspiration pneumonia, neuro signs
-no reported cases in people
-growing concerns of exposure to other ruminants

Question 15

What are the CWD management steps being taken in TN?

Answer 15

-all deer and harvested elk are tested
-all sick wild animals are tested
-incineration of carcasses
-restrictions on live deer movement
-increased bag limits on deer
-restrictions on practices that concentrate deer

Question 16

What are the characteristics of prion treatment?

Answer 16

-no vaccine or preventative
-resistant to most disinfectants
-must treat with bleach, preferably overnight