Reovirdae Birnaviridae Pibicornavirdae Flashcards
Reo: “Respiratory Enteric orphan
* “orphan virus“ viruses have been _______, but are __ associated with any known disease.
observed, not
Classification of the family Reoviridae
_____ dependent RNA polymerase
The family Reoviridae is made up of Two subfamilies:
1. ?
2. ?
RNA, Sedoreoviriae, Spinareovirnae
General Properties of Reoviruses
* _________ –shaped medium 80 nm diameter
**** Non-_________ has ___, and ____ capsid layers (____ and ____ core)
* Each of the two capsids has ______
symmetry
**** Outer capsid (VP__, VP___)
* **Inner core: VP__
* Outer core: VP__
** Transcription complex: (VP__, __, and __)
** _____ segmented _____-stranded RNA
** Genome: have between __ and ___ segments
** Genome size varies from ___ to __ kbs
** Replication - Full ______ replication
Spherical, enveloped, outer, inner, inner, outer, icosahedral, 2, 5, 3, 7, 1, 4, 6, Linear, double, 10, 12, 15, 27, cytoplasmic
What virus is pictured below?
Reoviruses
What virus can be seen below?
Reovirus
Reovirus genome structure
- ***___-___ segments __RNA
- Non-enveloped-RNA viruses
possessing a double shelled capsid - Packaged 1 copy per particle
- Transcripts represent genome-length
mRNAs - Genome segments can reassort
between related strains
** _______, ds-RNA - 10 (___) /11 (_____)
segments in - three distinct size classes:
**L - encodes proteins designated __
**M - encodes proteins designated __
***S - encodes proteins designated __
10, 12, ds, Segmented, Reo’s, Rota’s, (lambda) λ, μ, σ (sigma)
What virus is pictured below?
Reovirus
Comparison of two distinct core particle morphologies (spiked and unspiked) present
amongst genera within the subfamilies of the Spinareovirinae and Sedoreovirinae
Each of the viruses are all apart of the ________ family, but they all look different.
Reovirus
In the Reovirus replication cycle, the virus enters the host cell via ____________.
Endocytosis
Describe the reovirus replication cycle
Virus attach to receptors, endocytosis virus in the endosome and the
copying the viral genome and viral protein, assemble together and release via
leading to the
release into the cytoplasm and start
method mediated by
There are viral inclusion bodies in the
Back
pH decreases, acidification, budding, NS3, cytoplasm
1- African Horse Sickness Virus (AHSV)
* African horse sickness is a serious, often fatal disease of ?
** Serotype ___ is widespread in endemic regions, while serotypes __ to __ are
found only in limited geographic areas.
** Spread by infected _____ (______ _______) in the genus _______ and is not contagious by casual contact
* The disease primarily occurs in Africa, but outbreaks have been reported in Egypt, parts of the Middle East, Spain, Portugal, Morocco, Pakistan and India.
** Virus is inactivated by
– _______ (temps greater than _____)
– pH less than __, or ___ or ____
– _____ disinfectants
** Rapidly destroyed in carcasses that have undergone?
* AHSV: infects horses, donkeys, mule, zebra
horses, mules, and donkeys
9, 1, 8, insects, biting midges, Culicoides, Heat, 140oF, 6, 12, greater, Acidic, rigor mortis
AHSV-OIE Disease Distribution Map
* Endemic in ?
* Outbreaks
– Southern and northern Africa
– Near and Middle East
– Spain and Portugal
sub-Saharan Africa
AHSV-Succeptability /IP/Morbidity/Mortality
* Varies with species, previous immunity, form of disease
* Mortality based on _______
– Horse particularly susceptible
– Mortality of infected animals
* Horses: ____%
* Donkeys: ___%
* Mule; ___%
-Dogs may seroconvert through arthropod bites
Forms of the disease and associated mortality rates
species, 95, 50, 10
The per acute form of African Horse Sickness virus is the?
The subacute form of African Horse Sickness virus is the?
pulmonary form, edematous/cardiac
***I- AHSV-Peracute - Pulmonary Form
* Acute _________
* Sudden, severe ________ distress
* Dyspnea, tachypnea, Profuse sweating, spasmodic coughing
** _____ ___________ nasal exudate
* Rapid death (few hours)
fever, respiratory, Frothy, serofibrinous
***II-AHSV-Subacute Edematous - _____ Form
** Edema of ________ fossae, eyelids
* Cheeks, lips, tongue, intermandibular space
* Neck, thorax, chestNot in lower legs
* If animal recovers, swellings subside over 3-8 days
Cardiac, supraorbital
***III- AHSV-Subacute - ____ Form
* Cardiac signs usually subclinical Followed by severe respiratory distress
* Mild respiratory signs
* Followed by edema and death
** Mortality __-__%
Cardiac, 70-80
IV-AHSV-Acute - ___ Form
* Pulmonary and cardiac forms
* Cardiac signs usually subclinical followed by severe respiratory distress
* Mild respiratory signs followed by edema and death
Mixed
What virus can be seen below?
AHSV
Top two rows = AHSV -I
Bottom row = AHSV -II
AHSV-Diagnosis
* Clinical signs
– **__________ swelling is characteristic
* Clinical signs
– Supraorbital swelling suggestive for AHSV
* Laboratory diagnosis
– Virus isolation & identification
– Serology
– Antigen detections (ELISA, IF)
– ***-__________ __________ inclusion bodies
Supraorbital, Granular intracytoplasmic
What virus is this horse suffering from? What can be seen in the histological image above?
AHSV - Severe edema of the eyelid
Granular intracytoplasmic inclusion bodies
AHSV- control measures
** ________control
Spraying all Equidae with insect _____
Insecticides
Vaccination of susceptible
animals (preferably with the monovalent
vaccine for the outbreak serotype)
Vector, repellants
3- Bluetongue Virus (BTV)
causes what diseases?
- Sore Muzzle, Pseudo Foot-and-Mouth Disease, Muzzle Disease
Blue tongue virus was First described in
South Africa
Blue tongue virus has a ______________ distribution
worldwide
BlueTongue Virus: a ____-_________, ______-borne, viral disease of _________. It primarily affects _____ and _____ _______, with asymptomatic infections occurring in ?
non-contagious, insect, ruminants, sheep, wild, ruminants, cattle, goats, deer
Bluetongue virus has how many serotypes worldwide?
Morbidity can be as high as _____%
Mortality is usually __-___%
24 serotypes identified worldwide, 100, 0-30
BTV : transmitted by _______ ______ in the genus ________
Principal vector (U.S.)
* C. variipennis var. sonorensis
In utero, Mechanical, Venereal?
biting midges, Culicoide
BTV: is not a _________ disease; the virus can be transmitted to the ______ in utero or spread ___________ on surgical equipment
and needles
contagious, fetus, mechanically
Although BTV can be found in ______, venereal spread does not
appear to be a major route of infection
semen
BTV has been isolated from all countries except _________
Antarctica
BTV
Sheep: Severity of disease
varies based on?
- Breed
- Strain of virus
- Environmental
stress
BTV - USA
Only one monovalent live vaccine against serotype-___
10
Principal vectors of BTV in US - ?
C. sonorensis and C. insignis
BTV clinical signs
Clinical signs - reflect the damage that this virus causes to vascular endothelium and the
resultant changes to capillary permeability and subsequent intravascular coagulation.
Fever, edema of lips, nose, face, submandibular area, eyelids, and sometimes ears;
congestion of mouth, nose, nasal cavities, conjunctiva, and coronary bands; and lameness
and depression
In North America, ______ ______ ______ (Odocoileus virginianus), ________ _______ (Antilocapra americana), and desert bighorn sheep (Ovis canadensis) are also susceptible to _____ infection
white-tailed deer, pronghorn antelope, BTV
White-tailed deer and pronghorn antelope infected by BTV develop ?
severe hemorrhagic disease leading
to sudden death
These ruminants are suffering from what viral infection? Describe the clinical signs seen.
In sheep, the clinical signs may include fever, excessive salivation, depression, dyspnea, and panting. The muzzle, lips, and ears are hyperemic, and the lips and tongue may be very swollen. The tongue is occasionally cyanotic (“Blue tongue”)
swollen, and protrudes from the mouth.
In cases of BlueTongue Virus, The coronary bands on the hooves are often _______ and inflamed, and the hooves are painful; lameness is
common.
hyperemic
BTV incubation period is ?
5-10 days
What condition did this animal suffer from?
Bluetongue virus
In the case of blue tongue virus, during post mortem examination you can see?
Tongue
– Swollen, protruding
– Cyanotic
= “blue-tongue”
In the case of blue tongue virus, during post mortem examination you can see?
Face and ears
edematous
* Dry, crusty exudate on
nostrils
In the case of blue tongue virus, during post mortem examination you can see?
Coronary bands hyperemic
This is shared with foot and mouth disease
In the case of blue tongue virus, during post mortem examination you can see?
Hydranencephaly
Pregnant ewes infected during the first trimester may
- abortion
-give birth to “dummy” lambs (dull, unresponsive)
Erosions, crusts
around nose
and teats
How do you diagnose BTV?
- History
- Clinical signs
– Insect activity
– Wasting or foot rot - Laboratory
– Virus isolation
– ELISA, IFA, VN
– PCR
– Serology, complement
fixation
– Examination of proteins
How do you control BTV?
- Control of vectors by insecticide
- Quarantine and movement controls
– Prevent spread of virus - Vaccines are available, but are
specific for each serotype
What are the differential diagnoses for BTV?
Epizootic Hemorrhagic Disease (EHD) Belongs to ________ and has __ distinct serotypes (only two of these
(?) occur in the USA)
Orbivirus, 8, New Jersey and Alberta
EHD is an _____, ___________, often _____ viral disease of some ?
acute, infectious, fatal, wild
ruminants
Both BTV and EHD are antigenically ________
distinct
EHD
The mode of transmission of EHD in nature is via a ________, _______ fly or ______
Culicoides, biting, midge