Picornaviridae (Final)

Question 1

What are the four genera of Picornaviridae?

Main disease caused by each?

Answer 1

• Aphthovirus: FMD
• Cardiovirus: encephalomyelitis
• Enterovirus: swine vesicular
• Teschovirus: porcine

Question 2

General features of Picornaviridae

• structure
• genome
• environmental stability
• replication location

Answer 2

• non-enveloped, icosahedral
• single stranded, pos sense RNA
• genomic RNA is infectious
• stable in mucus and feces, can withstand strong sunlight, humidity preferred
• replication in cytoplasm

Question 3

Swine Vesicular Disease

• family, genus
• host
• transmission
• resistance

Answer 3

• picornaviridae, enterovirus
• swine are only natural host, but enzootic
• can be transmitted in pork products
• virus infects swine via skin abrasions and mucosa be ingestion and inhalation, also direct contact (fecal-oral)
• resistant to sodium carbonate

Question 4

Clinical features of Swine Vesicular Disease

Answer 4

• sudden appearance of lameness
• fever
• vesicles on junction between heel and coronary band
• lesions on snout, lips, and tongue
• may develop encephalomyelitis

Question 5

Foot and Mouth Disease

• family, genus
• hosts

Answer 5

• picornaviridae, aphthovirus
• in cloven hoofed animals
• zoonotic, foreign animal disease

Question 6

Clinical signs of FMD

Answer 6

• early signs: fever, salivation, nasal discharge
• lesions on buccal area and buccal cavity
• vesicles on coronary bands and interdigital spaces
• lesions on teats
• abortion
• death in young animals

Question 7

Transmission of FMD

Answer 7

• respiratory aerosols
• direct contact
• indirect contact (fomites)

Question 8

What are 4 genera of Paramyxovirinae, and what is the main disease each causes?

Answer 8

• Respirovirus: bovine parainfluenza virus 3
• Avulavirus: Newcastle disease
• Henipavirus: Nipah virus
• Morbilivirus: canine distemper

Question 9

General features of Paramyxoviridae

• structure
• genome
• location of replication

Answer 9

• pleomorphic, spherical, or filamentous
• enveloped with glycoprotein spikes
• herringbone shaped nucleocapsid
• linear, single stranded, neg sense RNA
• replication in cytoplasm

Question 10

What proteins are present on/in paramyxoviruses

Answer 10

3 membrane proteins: matrix, fusion, hemagglutinin

3 nucleocapsid proteins: RNA-binding protein, phosphoprotein, large polymerase

Question 11

Newcastle Disease

• family, genus
• host
• 5 pathotypes

Answer 11

• paramyxoviridae, avulavirus
• chickens highly susceptible
• viscertropic velogenic
• neurotropic velogenic
• mesogenic
• lentogenic or respiratory
• asymptomatic

Question 12

Newcastle Disease transmission

Answer 12

• direct contact with secretions (ingestion or inhalation)
• fomites
• chicks infected through egg
• survival in feces

Question 13

Lentogenic strains of Newcastle disease

• types of disease caused
• signs

Answer 13

• subclinical disease
• mild respiratory symptoms
• coughing, gasping, sneezing, and rales
• mortality negligable

Question 14

Mesogenic strains of Newcastle disease

• type of disease caused
• signs

Answer 14

• acute respiratory disease
• neurological signs
• mortality low

Question 15

Velogenic strains of Newcastle disease

• type of disease caused
• signs/effects

Answer 15

• severe disease, high mortality
• greenish or white, watery diarrhea, dyspnea, inflammation of head/neck, cyanosis
• neurologic: tremors, wing/leg paresis, torticollis
• drop in egg production
• sudden death with little signs

Question 16

Newcastle disease lesions

Answer 16

• not pathognomonic
• velogenic only
• swelling of periorbital area or entire head
• edema, hemorrhages, degeneration of ovaries
• ulcerations of resp/digestive lymphoid tissue

Question 17

Prevention/Control of Newcastle disease

Answer 17

• live vaccines: Ientogenic, Mesogenic
• inactivated and recombinant vaccines
• no treatment

Question 18

Nipah Virus

• family, genus
• hosts
• type of disease caused
• risk

Answer 18

• Paramyxoviridae, Henipavirus
• pigs and humans
• encephalitis in humans
• respiratory disease in pigs
• BSL 4 agent, bioterrorism

Question 19

Nipah virus transmission

Answer 19

• flying foxes (fruit bats) are carriers
• virus found in urine and partially eaten fruit
• dogs and cats may transmit virus
• vertical transmission in pigs

Question 20

Nipah virus clinical signs

Answer 20

Suckling piglets: high mortality
- labored breathing, muscle tremors
Young pigs: low mortality
- fever, labored breathing, nasal discharge, loud cough, neurological signs
Older pigs:
- neurological signs, respiratory signs, abortions

Question 21

Diagnosis of Nipah virus

Answer 21

• virus isolation
• virus neutralization
• RT-PCR
• immunohistochemistry

Question 22

Canine Distemper virus

• family, genus
• main reservoir in America
• transmission

Answer 22

• paramyxoviridae, morbilivirus
• raccoons with America-1
• shed in all secretions/excretions
• direct contact, droplets, aerosols
• unstable in environment

Question 23

Canine Distemper clinical signs

Answer 23

• 50% are subclinical or mild: nasal discharge, coughing, labored breathing
• severe: fever, inflammation of upper resp tract, leukopenia, conjuncitivitis
• vomiting, diarrhea
• puppies: pneumonia, enteritis, conjunctivitis, rhinitis, tracheitis
• CNS signs, indicate poor prognosis
• hyperkeratosis of footpads and nose

Question 24

Pathogenesis of Canine Distemper

Answer 24

• replicates in upper resp tract macrophages
• spreads to tonsils and lymph nodes
• infects all cells expressing CD150
• enters bloodstream and infects T and B cells
• infection of epithelial cells in lungs, bladder, and skin

Question 25

Orthomyxoviridae

• what are the 5 genera?
• hosts of each

Answer 25

• Influenza A: humans, equine, swine, poultry
• Influenza B: humans
• Influenza C: human and swine
• Thogotovirus: tick-borne in livestock and humans
• Isavirus: infectious salmonid anemia