Picornaviridae

Question 1

What viruses are part of the Picornaviridae family?

Answer 1

Enterovirus
Cardiovirus
Rhinovirus
Aphthovirus
Hepatovirus
Parechovirus

Question 2

Are Picornaviridae virus’s RNA or DNA virus? ss or ds? structure?

Answer 2

ss (+) RNA, linear

Question 3

What virus is responsible for Foot and Mouth Disease?

Answer 3

Apththovirus

Question 4

Is Aphthovirus envelope or non-envelope virus?

Answer 4

No envelope

survives drying

Question 5

What are the serotypes for FMDV?

Answer 5

Type O
Type A
Type Asia 1
Type SAT 1-2
Type C

Question 6

What is FMDV susceptible to for inactivation? Give 4 examples

Answer 6

pH - > 9 : 5% acetic acid or other acids or 1-2% sodium hydroxide or other alkalis

Phenolic and quarternary ammonium compounds effective

Oxidizing agents (bleach) - environment w/o organic substances! Detergents increase effectiveness

Heat

Question 7

What animals are susceptible to FMDV? What animal won’t be affected?

Answer 7

domestic and wild ruminants and pigs = cloven hoof animal
(cattle, buffalo, sheep, goats, camelids, deer, pigs, rabbits, mice, guinea pigs, chickens, humans)

Horses are not affected

Question 8

How does FMD present?

Answer 8

systemic disease
high fever
vesicles on epithelial surfaces

Question 9

Is FMD fatal in adults?

Answer 9

Not usually but will cause economic losses

Can be fatal in young animals – myocarditis

Question 10

What countries are free of FMD?

Answer 10

North America
Australia
New Zeland
UK

Question 11

How many important antigenic proteins does FMD have?

Answer 11

VP1
VP2
VP3
VP4

Question 12

Are lab animals like rabbits,mice and guinea pigs susceptible to FMD?

Answer 12

Yes

Question 13

What is the amplifying host for FMD? What does this mean?

Answer 13

Pigs

secrete large amounts of virus in breath, air borne spread

Question 14

What is the sentinel host for FMD? What does this mean?

Answer 14

Cattle

Highly sensitive to infection by respiratory route

Question 15

What is the maintenance host for FMD? What does this mean?

Answer 15

Sheep

Mild asymptomatic disease, can spread through flocks before detection

Question 16

What is the route of infection for FMD?

Answer 16

inhalation
ingestion
AI

Question 17

What is the incubation period for FMD?

Answer 17

36 hours, usually 3-10 days

Question 18

How long can FMD persist?

Answer 18

months to years in partially immune animals, life time in some species

Question 19

What causes the death of young animals with FMD?

Answer 19

Myocarditis

Question 20

When does virus shedding start for FMD? What is the significance?

Answer 20

1-4 days before clinical signs appear

Before we know the animals are sick, the herd is affected

Question 21

What is the infectious dose for FMDV?

Answer 21

< 10 particles +

Question 22

What is the transmission for FMDV?

Answer 22

Aerosol
Direct contact
Contaminated animal products
Contaminated pastures
Wind-borne carriage of infectious aerosols
Possible passive transmission by birds and humans

Question 23

What is the pathogenesis for FMD?

Answer 23

Large amount of virus present in mucosal secretions, milk, urine, and feces of infected animals –> infection of epithelial cells –> cytoplasmic replication –> virus assembly –> cell lysis –> virus release –> localized infection of regional lymph nodes –> virus enters blood = viremia –> dissemination to secondary sites –> increase in virus load on host –> virus collects in cornified epithelium (feet, mammary gland, mouth and tongue)

Question 24

What are primary sites of FMDV replication?

Answer 24

At the point of entry

• soft palate
• dorsal root of pharynx
• Dermal and subdermal tissue near a skin abrasion

Question 25

What are 7 factors that allow rapid spread and persistance in a population?

Answer 25

1. antigenic variation 2. large host range 3. low infectious dose 4. large amounts of virus b/f clinical signs develop 5. no clinical signs in some species (sheep) -- allows spread 6. persistent infection in partially immune 7. hardy virus (many routes of spread)

Question 26

Will abortion occur in pregnant animals infected with FMDV? What internal organs are affected with FMD?

Answer 26

Yes Pancreas and heart

Question 27

What are the clinical signs and lesions of FMD?

Answer 27

``` Fever, depression, anorexia formation of vesicles Excessive salivation Smacking of the lips Vesicle rupture Lameness Abortion Hear and panceras also have lesions ```

Question 28

What is the mortality and morbidity of FMD? Use the words high or low

Answer 28

High morbidity | Low mortality

Question 29

What kind of vaccine is available for FMD?

Answer 29

inactivated vaccine - safe and effective

Question 30

What can provide an animal protection of FMD?

Answer 30

Vaccine | Good humoral immune response following recover provides protection against the same serotype

Question 31

What are problems with the FMD vaccine?

Answer 31

No cross protection if wrong serotype short-lived immunity partial protection if variant: does not prevent infection, persistent infection Cannot distinguish b/w vaccinated and infected animal Detection easier if no vaccination

Question 32

How many vaccines are required per year for FMD if we are using it?

Answer 32

2-3 | Adjuvanted vaccine protect for up to 1 year

Question 33

What types of FMDV does the vaccine work against?

Answer 33

Types A, O and C

Question 34

Is there a vaccination bank available for FMD in the USA?

Answer 34

Yes -- associated with USDA

Question 35

What is prevention protocal for FMD in endemic countries? FMD free countries?

Answer 35

ENDEMIC - vaccination - vaccination and slaughter FMD free - prevent introduction - in face of outbreak: test and slaughter, ring-vaccination and slaughter, ring-vaccination and slaughter only sick animals

Question 36

What are three options for control of FMD?

Answer 36

1. Test and slughter (UK) 2. Vaccinate and slaughter 3. Vaccinate and only slaughter sick animals

Question 37

How do you diagnose FMD?

Answer 37

Clinical signs -- may confuse w/ other vesicular dz Laboratory: inoculated onto susceptible cells ELISA

Question 38

What samples should be collected for laboratory testing to dx FMD?

Answer 38

epithelium surrounding vesicle | Fluid contained within the vesicle

Question 39

What are tests looking for when detecting FMD?

Answer 39

Viral antigen