(08) Picornaviridae & Reoviridae

Question 1

(Viruses with dsRNA)

1. What are two groups?
2. What are three types in Reoviridae?

Answer 1

1. reociridae and birnaviridae
2. rotaviruses
3. bluetongue virus
4. african horse sickness

Question 2

(General Characteristics of Reoviruses)

1. enveloped?
2. shape?
3. How many capside layers?
4. RNA segmented?
5. where do they replicate?

Answer 2

1. non-enveloped
2. spherical
3. 3
4. yes (can easily recombine)
5. cytoplasm (see inclusion bodies in cytoplasm)

Question 3

(Rotavirus Structure)

1. Outer capsid protein made up of what two proteins? What do they do?
2. How many serogroups? most common serogroup?
3. RNA composed of how many segments? make how many proteins?

Answer 3

1. VP4 (attachment receptor)
2. seven; serogroup A
3. 11, 12

Question 4

(General Characteristics)

1. Orbiviruses are what kind of viruses? Seen in a circumscribed geographical area as the what?
2. What kind of viruses are rotaviruses?

Answer 4

1. arboviruses, vector
2. rotaviruses (cause scours in newborns - all domestic animal and birds have one)

Question 5

Answer 5

B

Question 6

(Picornaviridae)

1. how big?
2. What is the important genera?

Answer 6

1. one of the smallest
2. apthovirus (causes foot and mouth disease)

Question 7

(Picornaviridae)

(General Characteristics)

1. enveloped or non?
2. RNA single or double? + or - sense?
3. How many capside layers?
4. Stability in pH?
5. Replication occurs where?
6. How is virus spread/released?

Answer 7

1. non
2. single; + (can make copies right away)
3. one
4. varied (aptho unstable below 7) - Entero/cardio stable at PH 3
5. cytoplasm
6. cell lysis and virus release

Question 8

know what kinds of disease these cause

also notice the size thing - supposedly something wronge there

Question 9

(Rotavirus)

1. Major cuase of what?
2. What levels of titer excreted in feces?
3. Inactivated by what?
4. How sensitive to chlorination?

Answer 9

1. neonatal diarrhea
2. high (10^11/gm)
3. phenolic disinfectants
4. relatively insenitive

Question 10

1-3. What three viruses cause diarrhea in neonates?

Answer 10

1. rotavirus
2. coronavirus
3. BVDV

Question 11

(Susceptibily of neonates to Rotaviruses and Coronaviruses)

1. Which of the two lasts longer?
2. Note the thing about the colostral antibodies…
3. Is mucosal or systemic antibody more important?

Answer 11

1. coronaviruses
2. mucosal

Question 12

(Maintenance of Rotaviruses in Populations)

1. stable in envrionment?
2. persistence and periodic shedding? (what does this cause)?

Answer 12

1. yes
2. yes; subclinical infection in calves and adults

Question 13

(Rotavirus Pathogenesis)

1. Usually seen in 1-8 weeks olds. What is the incubation period?
2. Infection leads to destruction of what?

Answer 13

1. 16-24 hours
2. epithelial cells (at the apices of villi in small intestines) - this leads to poor absorption and then diarhhea

Question 14

(Effect of rate of enterocyte replacement on disease (by rotavirus))

1. Rate is low in young calves - does this make them more or less susceptible?
2. later on… competition between what and infection?

Answer 14

1. more
2. replacement (better ability to replace causes less disease)

Question 15

(Rotavirus infection of intestinal cells)

1. How long is incubation?
2. Death is the result of what?

Answer 15

1. short incubation (~12 hours)
2. dehyration and secondary bacterial infection

(just look at this slide a little)

Question 16

(Diagnosis of Rotavirus)

1-3. What three ways can these be detected?

4. Can they be isolated?

Answer 16

1. detection of virus in fecal smears by FAT
2. EM and immune EM
3. antigen capture ELISA
4. difficult to isolate

(can also do electrophoresis of RNA segments when looking for specific serotypes)

Question 17

(Blue tongue)

1. What kind of disease is blue tongue disease (contagious or non) (wat is the vector)?
2. they are part of non-traffic trade barrier - virus causes much economic loss
3. How many serotypes? how many in US?
4. Also infects what?

Answer 17

1. It is a non-contagious (don’t get from another animal - need a vector) arthropod borne viral disease of sheep
2. 25; 5
3. cattle (non-symptomatic), goats, deer

Question 18

(BV pathogenesis)

1. how long is incubation?
2. Virus replicates where?
3. Can it cause viremia? for how long?
4. Because cattle can get it for long periods and don’t show any symptoms - what does this mean?
5. What does it cause in deer and antelope?

Answer 18

1. short
2. vascular endothelial cells
3. yes; 14 to 28 days
4. means that cattle can spread it
5. peracute hemorhagic disease

Question 19

(BV pathogenesis)

1. What is the vector?
2. Virus replicates where in vector?

Answer 19

1. culicoides spp
2. salivary glands

(virus persists for lifespan of vector)

Question 20

Answer 20

B

Question 21

Answer 21

C (can replicate in here)

Question 22

He says to look at this

Question 23

1. What causes the tongue to turn blue?

Answer 23

1. loss of vasculature

(also get coronary bands and torticolis)

Question 24

(Diagnosis of Bluetongue)

1. What is the best way to diagnose and identify?

Answer 24

1. RT-PCR

(Serology not so good cause you get a lot of false negatives)

Question 25

(Control of Bluetongue) (his voice cut out here - so if you have time page through these slides quick) 1. Controlling what help control bluetongue? 2. Is immunity serotype specific? 3. Can bluetongue survive outside of susceptible hosts and insect vectors?

Answer 25

1. the Culicoides spp (the vector) 2. yes 3. no (carcasses not a source) - it is non-contagious

Question 26

Answer 26

figure this one out

Question 27

(Foot and mouth disease) 1. Causes a highly contagious and debilitating vesicular disease. 2. Inactivated at what pHs? 3. What is the host range?

Answer 27

2. less than 6.5 and greater than 11 3. all cloven hoofed animals

Question 28

(Foot and Mouth)

Question 29

(Foot and Mouth) 1. Where is greatest concentration of virus? 2. Transmitted by what?

Answer 29

1. in vesicular fluid 2. direct contact, inhalation or ingestion

Question 30

(Foot and Mouth) 1-3. What are three clinical signs?

Answer 30

1. Profuse salivation 2. Ruptured tongue vesicles 3. Vesicular lesions

Question 31

(Foot and Mouth) 1. How high is morbidity (the rate of incidence of disease)? 2. mortality?

Answer 31

1. 100% 2. less than 1% (heavy mortality in calves though - due to acute myocarditis)

Question 32

(Foot and Mouth) in sheep and goats

Question 33

look at these

Answer 33

Question 34

Diagnosis of FMDV

Question 35

Answer 35

figure this out

Question 36

Encephalomyocarditis virus (EMC) 1. causes what in sows? 2. control it how?

Answer 36

1. reproductive failure 2. reduce rodent population (they carry it), by vaccination