Class III dsRNA VIRUSES

Question 1

Group III dsRNA

3 Families

Answer 1

Birna
Picobirna
Reo

Question 2

• Nonenveloped, icosahedral, bisegmented genome;

Natural hosts:
salmonid fish
birds
insects

Answer 2

Birnaviridae

Question 3

• Nonenveloped, icosahedral, bisegmented genome;

Natural hosts:
mammals
possibly bacteria &
invertebrates

Answer 3

Picobirnaviridae

Question 4

• Nonenveloped, icosahedral, multilayered capsids, 10-12 segments;

Wide host range:
humans
vertebrates
invertebrates
plants
protists
fungi

Answer 4

Reoviridae

Question 5

Group III dsRNA

BOARding flight 382 in 10-12 minute

Answer 5

• Bunyaviruses (3 segments)
• Orthomyxoviruses (8 segments)
• Arenaviruses (2 segments)
• Reoviruses (10-12 segments)

Question 6

2 Families: (formerly Reoviridae)

Answer 6

A. Sedoreoviridae
B. Spinareoviridae

Question 7

 Have relatively large spikes or
turrets situated at the 12
icosahedral vertices of either the
virion or core particles

Answer 7

Spinareoviridae

Question 8

REO meaning

Answer 8

Respiratory
Enteric
Orphan

Question 9

 Naked viruses with double-
layered protein capsids
containing 10-12 segments of
the dsRNA genomes
(double:double virus);

60-80 nm

 Stable in detergents, over wide
pH and temperature ranges,
even in airborne aerosols

Answer 9

Sedoreoviridae

Question 10

Naked RNA viruses

Answer 10

Picorna
Reo
Calici

Question 11

Sedoreoviridae

GENERA: ROOC

Answer 11

1. Rotaviruses
2. Orthoreoviruses
3. Orbiviruses
4. Coltiviruses

Question 12

 Most important global cause of infantile gastroenteritis with potential dehydration

 most common in daycare centers & kindergartens

Answer 12

Rotavirus Group A

Question 13

Major cause of acute diarrhea in the U.S. during winter

adult diarrhea, severe gastroenteritis (any age)

Answer 13

Rotavirus Group B

Question 14

Global Burden of Disease 2019 study:
________ infection– leading cause of diarrheal deaths (19.11%)

 Higher in African, Oceanian, & South Asian countries (past 3 decades)

 High risk:
Children <5 years old &
elderly >70 years old

Answer 14

Rotavirus infection

Question 15

Rotavirus
 Transmission:

Answer 15

Fecal-oral route

Question 16

Pathogenicity:
 Mucosal damage & villous atrophy → impaired absorption of sodium & loss of potassium → non-bloody, watery diarrhea

 Viral enterotoxin, NSP4, nonstructural glycoprotein

Answer 16

Reoviruses - Rotavirus

Question 17

Reoviruses - Rotavirus

Clinical features:
 Incubation period:______
_____ and ______, 3-7 days
________ (dry mucosa, dry skin, tachycardia

Answer 17

1-3 days

Vomiting and watery diarrhea

Mild to severe dehydration

Question 18

Reoviruses - Rotavirus
 Dx:
 Tx:

Answer 18

Antigen detection in stool via enzyme immunoassay (EIA),
most common

Supportive – oral rehydration, IV fluids in patients with
severe dehydration

Question 19

remains a leading cause of
hospitalization and death in children under five years of age
in the Philippines.

vaccination was introduced into
the national immunization program in 2012 but has since
been limited to one region due to cost considerations

Answer 19

Rotavirus gastroenteritis

Question 20

Reoviruses
2 (arboviruses)

Answer 20

Coltivirus & Orbivirus

Question 21

Coltiviruses:
infect vertebrates and invertebrates
 Coltiviruses =

Answer 21

Colorado tick fever

Question 22

Reo

Acute disease, with fever, vomiting, headache,
severe myalgia, no rash (distinguished from
RMSF); a self-limiting disease

Transmission: Arthropod bite (wood tick, Dermacentor andersoni)

Tissue tropism: erythrocytes

Answer 22

Coltiviruses

Question 23

Coltivirus

Transmission:
Tissue tropism:

Answer 23

Arthropod bite (wood tick, Dermacentor andersoni)

erythrocytes

Question 24

Reo

: infect arthropods, Culicoides (midge), mosquitoes, sand flies, ticks, & vertebrate hosts

Answer 24

Orbiviruses

Question 25

 (Subfamily Spinareovirinae): The ‘prototype’ virus discovered in the early 1950s was isolated from the respiratory & gastrointestinal tracts of both sick and healthy individuals

Answer 25

Orthoreoviruses

Question 26

cause asymptomatic infections in humans; associated with mild upper respiratory tract & gastrointestinal illnesses, biliary atresia (childhood liver disease – narrow / blocked /absent bile ducts); no convincing data exist -- orphaned vertebrates serve as natural hosts

Answer 26

Orthoreoviruses