Foot and Mouth Disease

Question 1

What is the aetiology of FMD?

What are the different serotypes?

Answer 1

Picornaviridae, Aphthovirus, RNA single strand

7 distinct types

Serotype:

A
O
C
Asia 1
SAT 1
SAT 2
SAT 3

Question 2

What are the susceptible species to FMD?

Answer 2

Cattle

Sheep

Goats

Pigs

Wild boar and pigs

Water buffalo

Deer

Camels

Question 3

How are the different serotypes distributed?

Answer 3

Serotypes A and O in most endemic regions

Asia 1 found in FMD endemic regions of Asia

C has not been seen since 2004

African buffalo is the natural host for SAT

Question 4

What is the incubation period?

Mortality and Mobidity?

Answer 4

Incubation 2-12 days

High morbidity- 100%

Low mortality- 2-20%

Question 5

What are the clinical signs of FMD in Cattle?

Answer 5

• Drop in milk yield
• Rectal temp 40.5d
• Drroling thick ‘ropey’ saliva
• Lip smacking
• Depressed
• Uncomfortable on feet
• Vesicles- mouth- tongue, dental pad, hard palate, lips, gums, muzzle
• Vesicles- feed- coronary band, interdigital space
• Vesicles- teat udder
• Abortions
• Death in young animals

Question 6

What are the clinical signs in sheep, goats, and pigs of FMD?

Answer 6

Sheep-
Mild if any
Fever
Oral lesions
Lameness

Pigs-
Foot lesions- more severe than cattle- coronary band, interdigital
Snout vesicles
Oral less common

Question 7

What are the DDXs for FMD?

Answer 7

Swine-
vesicular stomatitis, swine vesicular disease, vesicular ecanthema, foot rot, chemical and thermal burns

Cattle-
rinderpest, IBR, BVD, MCF, Blue tongue
Bovine mammilitis, Bovine popular stomatitis

Question 8

How is FMD diagnosed?

Answer 8

Clinical signs

Lab
Viral isolation- tissue culture

Antigen detection- ELISA, PCR

Antibody- ELISA, SNT

Genetic analysis- RT PCR

Question 9

How is FMD transmitted?

What are the epidemiological factors?

Answer 9

Transmission-
Inhalation of aerosol or droplets, oral infection poor route in ruminants, pigs usually initially via oral- swill feeding
Virus excretion finished within 6 days

Epidemiology factors-
Viral serotypes, multiplication, production, stability, infective dose, carrier

Question 10

In the saliva at 37, 26, and 4 degrees how long does the virus survive?

Answer 10

Saliva 37 degrees- 2 days

Saliva 26 degrees- 3 weeks

Saliva 4 degrees- 5 weeks

Question 11

How can FMD virus be inactivated?

Answer 11

Temperature- progressively inactivated by temperatures above 50 degrees

pH- inactivated pH <6 or >9

Disinfectants
inactivated by sodium hydroxide, sodium carbonate, citric acid

Question 12

How was FMD excreted?

Answer 12

Question 13

What is the infectious dose for FMD?

Answer 13

Question 14

Why does FMD need to be controlled and eradicated?

Answer 14

Reduced productivity

Reduced milk production may continue if animals recover

Mortality in young animals

Restricted market access

Question 15

What constraints are there for FMD control?

Answer 15

Causing least disruption

Minimising no of animals that need to be slaughtered

Minimise damage to environment

Minimise the burden to taxpayer and public

Question 16

What are the different options for FMD control?

Answer 16

• Do nothing
• Prophylactic vaccination
• Stamping out policy- the slaughter of any affected or suspected (exposed)
• Stamping out with vaccination to kill (suppressive)
  
  • Stamping out with vaccination to live (protective)

Vaccination on its own would not eradicate the virus

Question 17

How was FMD controlled in 2001?

Answer 17

Restrict and control national movements of animals

Identify disease

Impose 3km protection zone and 10km surveillance zone

Cull all animals on confirmed infected farms within 24 hours

Rapid and safe carcass disposal

Cleaning, disinfection and restocking