94. Bovine spongiform encephalopathy, feline spongiform encephalopathy (Zoon).

Question 1

History?

Answer 1

History

• 1986: UK mainly dairy herds ➝ increase milk production, protein feed supplement of animal origin was given
• Changes in protein processing practice number of cases dropped
• Zoo ruminants and big cats, cats, humans

Question 2

Etiology?

Answer 2

Etiology

• Classic BSE prion
• Atypical BSE prions ➝ spontaneous formation (rare), H type, L type
• Emerges in some individual animals within herd

Question 3

Transmission?

Answer 3

Transmission

• No spread from animal to animal (not horizontally and not vertically)
• No shedding
• Zoo ruminants also affected
• Artificial transmission
• Parenteral: mous, sheep, goat, swine, mink and monkeys
• Per os: sheep, goat, mink, lemur
• No transmission: swine (per os), poultry
• Cattle: 1g of infected brain material per os

Question 4

Pathogenesis?

Answer 4

Pathogenesis

1. Infection: per os
2. Intestinal nerve endings
3. Passes along nerves
4. Brain

Question 5

Clinical signs?

Answer 5

Clinical signs

• Incubation: 3-5 years
• Slowly progressing symptoms
• Behavioural change
• Hypersensitivity, nervousness, shy, head-down posture
• Aggression, resist milking
• Motor disorders, weakness, ataxia, hypermetria
• Tremor
• Weight loss, decreasing milk production
• Death

Question 6

Diagnosis?

Answer 6

Diagnosis

• Live animals: suspicion (anamnesis, clinical signs)
• Histology, IHC
• Immunological tests ➝ ELISA, Western blot
• No lab method to detect BSE in live animals
• DD: other diseases with neural symptoms

Question 7

Prevention, Control?

Answer 7

Prevention, Control

• Notifiable disease
• Ruminants: ban on protein feeding
• Except: milk, colostrum, milk powder, eggs, fish meal
• Meat and bone meal of ruminant origin cannot be fed
• Import restrictions
• Investigation of clinical cases: nervous symptoms
• Screening
• Dead showing nervous symptoms
• Older than 24 months, dead, culled, quarantined
• Older than 30 (72) months: slaughtered animals

• Disposal of risky material: SRM

Question 8

Feline spongiform encephalopathy?

Answer 8

Feline Spongiform Encephalopathy of Cats

Occurrence

• In UK mainly
• Older cats: 2-5 years
• Big cats in zoos
• Feed containing pathogenic prions

Clinical signs

• Changes in general behaviour: aggression, shy
• Hypersensitive, aggressive
• Salivation
• Dilated pupils
• Ataxia, weakness, spasms, paralysis