Reoviridae

Question 1

What are the 3 genera of veterinary importance in reoviridae?

Answer 1

• orthoreovirus: arthritis and tenosynovitis in poultry
• orbivirus: arthropod borne, infect horse (African horse sickness), ruminants (bluetongue)
• rotavirus: enteritis in neonatal farm animals

Question 2

Mammalian reovirus 1-3

Answer 2

Orthoreovirus

• isolated from many species of mammals
• hepaloencephalomyelitis in mice

Question 3

Avian reovirus 1-11

Answer 3

Orthoreovirus

• chickens, turkeys, geese
• arthritis, nephrosis, enteritis, chronic respiratory disease, myocarditis

Question 4

Bluetongue virus 1-25

Answer 4

Orbivirus

• sheep, cattle, deer
• bluetongue

Question 5

African horse sickness 1-9

Answer 5

Orbivirus

• horse, donkey, mule, zebras
• african horse sickness

Question 6

Equine encephalosis virus 1-5

Answer 6

Orbivirus

• horse
• abortion and encephalitis

Question 7

Epizootic hemorrhagic disease of deer virus 1-2

Answer 7

Orbivirus

• deer
• epizootic hemorrhagic disease

Question 8

Ibaraki virus

Answer 8

Orbivirus

• cattle (not in US)
• acute febrile disease similar to bluetongue

Question 9

Palyam virus 1-6

Answer 9

Orbivirus

• cattle (not in US)
• abortion, congenital abnormalities

Question 10

Rotaviruses

Answer 10

Host specific, infect virtually all animals

- enteritis

Question 11

Colorado tick fever virus, Eyach virus

Answer 11

Coltivirus

• zoonotic, small animals and humans
• colorado tick fever

Question 12

Aquareovirus

Answer 12

Viruses of fish and shellfish

Question 13

Reoviridae genome

Answer 13

Segmented (10-12), double stranded RNA genomes

• 10 for othoreovirus and orbivirus
• 11 for rotavirus
• 12 for coltivirus

Question 14

Disease of orthoreoviruses are usually insignificant, except in ______

Answer 14

Rodents, chickens, and turkeys

Question 15

Which genera of reoviruses is vector-borne?

Answer 15

Orbivirus

- have a resulting seasonal effect

Question 16

Orbiviruses have 3 layers: ______, ______, and _____

Answer 16

• inner core layer: VP1, VP4, VP6
• Core layer: VP3 and VP7 (group specific antigen)
• outer layer: VP2 and VP5 that are responsible for induction of immune response

Question 17

Rotaviruses often cause disease in ______

Answer 17

New-borne animals after maternal antibody has waned

- diarrhea is more severe than with other viruses

Question 18

What are the 7 major subgroups of rotavirus?

Answer 18

A-G based on VP6

• A: pathogens from humans, cattle, etc
• B: human pathogens only
• C and E: swine only pathogens!!!
• D and F: pathogens from fowl

Question 19

What is the most abundant viral protein, that is the major determinant of group reactivity?

Answer 19

VP6

- is the target of common diagnostic assays

Question 20

Reoviral replication

Answer 20

Involves synthesis of viral mRNA and genomic RNA by RNA dependent RNA polymerase

• is packed within virion particles
• reason why reoviral genomic RNA is NOT infectious!!

Question 21

T/F: Genetic reassortment occurs between viruses within each genus or subgroup

Answer 21

True

Question 22

Bluetongue infects both _____ and _____

Answer 22

Domestic and wild ruminants

Question 23

Bluetongue shares a common antigen with _______ and _______

Answer 23

Epizootic hemorrhagic disease of deer virus and African horse sickness virus

Question 24

Virulence of bluetongue virus

Answer 24

Varies due to 25 serotypes

• only 5 serotypes recognized in US
• seroprevalence of cattle in US is >18%

Question 25

Does bluetongue virus survive outside the host?

Answer 25

No | - transmission due to animal carcasses or meat products is not possible

Question 26

Is the cattle or sheep industry more heavily affected by bluetongue in the US?

Answer 26

Cattle industry | - cattle are often not noticeably ill, but they carry the disease for months after initial infection

Question 27

Bluetongue virus is transmitted by _______

Answer 27

Culicoides midges - disease is prevalent in mid-summer to early fall - female midges take up bluetongue viruses as they feed on blood of infected animals

Question 28

What midges make up the complex that is most involved in the spread of bluetongue virus?

Answer 28

- C variipennis variipennis - C variipennis sonorensis - C variipennis occidentalis

Question 29

Sheep affected with bluetongue

Answer 29

Swollen lips and tongue

Question 30

Cattle and goats affected with bluetongue

Answer 30

Usually subclinical, only 5% develop disease

Question 31

General symptoms of bluetongue

Answer 31

Fever, listlessness, lack of appetite, rapid breathing - mucous membranes of eyes, nose and mouth turn red and lips become swollen - 7-12 days in the disease you get lameness with petechical hemorrhage at coronary band and hooves may slough

Question 32

Bluetongue infection of pregnant animals

Answer 32

May result in abortion, stillbirth, or weak live birth | - early embryonic loss and decreased reproductive efficiency

Question 33

What is the most definitive means of BTV diagnosis?

Answer 33

Virus isolation from blood of viremic animals

Question 34

Bluetongue is a ______ disease

Answer 34

List A | - internationally regulated!!!

Question 35

Control of BTV

Answer 35

Based on vaccination of animals in endemic areas and decreasing number of insect vectors by bringing animals inside around dusk

Question 36

Is there a universal vaccine for bluetongue?

Answer 36

No, all vaccines are serotype dependent

Question 37

What is the number one viral agent to cause diarrhea in new borne calves?

Answer 37

Bovine rotavirus

Question 38

Transmission of BTV can also occur _______

Answer 38

Transplacentally | - cannot be transmitted between mammals

Question 39

Unlike rotavirus, BTV is susceptible to _______

Answer 39

Common disinfectants and low pH | - rotavirus are stable in wide range of environments

Question 40

_____ and _____ are neutralizing antigens and must be considered when vaccinating

Answer 40

VP4 and VP7