42. Foot and mouth disease (aetiology, epidemiology, pathogenesis, clinical signs, post mortem lesions).

Question 1

Foot & Mouth Disease: Occurrence

Answer 1

• Turkey, middle east, Arabic Peninsula, Africa, Asia & South Ameria
• Sporadic cases: Europe

Question 2

Foot & Mouth Disease: Regions free of the disease

Answer 2

• North & Central America
• Australia
• New Zealand
• Japan

Question 3

Foot & Mouth Disease: Causing virus

Answer 3

Foot & Mouth Disease Virus (FMDV)

• Family: Picornaviridae
• Genus: Aphthovirus

Question 4

Foot & Mouth Disease: Aetiology

Answer 4

• Good resistance
  
  • In manure for 40 days,
  • Frozen meat & milk powder for months
• Shedding starts 9 hrs after infection → FAST
• Cytopathic effects (CPE)
• Guinea pig foot scarring

Question 5

Foot & Mouth Disease: Subtypes & strains

Answer 5

• 7 serotypes: O & A are found worldwide
• SAT-1; SAT-2; SAT-3: Africa & Arabia
• Asia-1: Asia, Turkey & the Middle East
• Several subtypes
• Ø Cross-protection

Question 6

Foot & Mouth Disease: Epidemiology

Answer 6

NOTIFIABLE & ZOONOTIC DISEASE

• Susceptible species: Ru. [Bo.]; Sus.; Ca.; Ho.
• Swine shed 3000x more than cattle (but for less time)
• Long term carrying: Tonsil, lymphatic tissue & hoof
• Vaccinated animals can still carry & shed the virus

Question 7

Foot & Mouth Disease: How can it be spread

Answer 7

• Live animals (Direct, saliva, body fluids, milk & semen)
• Environment
• Contaminated feed & water
• People
• Raw meat & milk
• Skin & Fur
• Vehicles

Question 8

Foot & Mouth Disease: How long can it be carried in the body?

Answer 8

• Ruminants: Up to 3 years
• Swine: For a few weeks

Question 9

Foot & Mouth Disease: Pathogenesis

Answer 9

1. Infection: PO / Airborne
2. Primary replication in laryngeal & pharyngeal mucosa
3. Viraemia → Spread within the body
4. Vesicles on mucosa & skin

Question 10

Foot & Mouth Disease: CSx

Answer 10

• Mouth vesicles [Bo./Cap.]: from 2 days; tattered edge, red base; bacterial superinfection
• Feet: Severe lameness [Bo./Ov.] & loss of hoof keratin layer (swine)
• Wild animals: Mild symptoms
• Myocarditis in young animals → death

Question 11

Foot & Mouth Disease: Pathology

Answer 11

Vesicles & erosions on mucosa and hoof

Pale heart (in young)