Final Exam - Picornaviridae

Question 1

Two important genera of Picornaviridae

Answer 1

Aphtovirus and Enterovirus

Question 2

Picornaviridae Replication

Answer 2

Poliovirus does not enter cells through endocytosis.

Question 3

Enterovirus

Answer 3

Cause of Swine Vesicular Disease and Polioencephalomyelitis.

Question 4

Swine Vesicular Disease Virus (SVDV)

Answer 4

Enzootic in Italy. Resistant to ambient temperature and to sodium carbonate. Transmitted in pork products. Not found in NA/USA and is an FAD.

Question 5

SVDV Transmission

Answer 5

Virus infects swine via skin abrasions and mucosa by ingestion and inhalation. Direct contact among infected swine or with their excretions.

Question 6

SVDV Clinical Features

Answer 6

Sudden appearance of lameness. Vesicles appear at the junction between the heel and coronary band. Lesions on snout, lips and tongue. Some develop encephalomyelitis.

Question 7

SVDV Pathogenesis

Answer 7

Infection through fecal-oral route. Replication is in the GIT. Skin abrasion may act as portals of entry. Particularly feet. Viremic within 24 h.

Question 8

SVDV Diagnosis

Answer 8

Case should be treated as FMD. RT-PCR multiplexed assays which can detect multiple agents at once. ELISA if vesicular fluid is collected. Virus isolation in swine kidney cells.

Question 9

SVDV Vaccine

Answer 9

THERE IS NO VACCINE!

Question 10

Foot and Mouth Disease Virus (FMDV)

Answer 10

Picornaviridae, Aphthovirus. Not cross protective. A disease of cloven hoofed animals.

Question 11

FMDV Clinical Signs

Answer 11

Fever, excess salivation, nasal discharge (cattle). Initially vesicles on buccal areas, coronary bands and interdigital space. Recover in two weeks unless secondary infections arise.

Question 12

FMDV Clinical Signs in Sheep and Goats

Answer 12

Mild, if any, signs.

Question 13

Why care about FMD?

Answer 13

Highly contagious. Loss of livestock production cause economic loss. Limitation of international trade in livestock and animal products.

Question 14

FMDV Transmission

Answer 14

Respiratory aerosols, direct contact and indirect contact via fomites.

Sheep = maintenance host and carrier for 4-6 mo.
Pigs = amplifier host and is not a carrier
Cattle = indicator host and is a carrier for 6-24 mo.

Question 15

FMDV Diagnosis

Answer 15

Virus isolation and identification (vesicular fluid). Antigen or nucleic acid detection. Complement fixation, ELISA and virus neutralization.

Question 16

FMDV Sample Collecting for Testing

Answer 16

Authorities should be contacted before collecting. Notify authorities and wait for instructions before collecting samples. Sample-s are sent under secure conditions and to authorized laboratories.

Question 17

FMDV Treatment

Answer 17

There is no treatment available. Outbreak results in quarantine, euthanization, and disposal. Vaccines are available.

Question 18

FMDV Disinfection

Answer 18

Effective solutions include: 2% sodium hydroxide (lye). 4% sodium carbonate (soda ash), 5.25% sodium hypochlorite (household bleach), 0.2 citric acid. Areas must be free of organic matter.

Question 19

FMDV - Vaccination

Answer 19

Killed vaccine, serotype specific. Used to control outbreak. Will have to have annual revaccination. Does not protect against infection with other serotypes.