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
What is the disease is the animal suffering from in the picture below?
Endothelial cells that line the blood vessels are damaged, resulting in
blood leaking through the walls, resulting in hemorrhages.
No organs appear to be exempt from hemorrhage
EHD - Virus isolation (cell culture, Intravenous injection in embryonated chicken eggs/ECE, inoculation of susceptible sheep or deer, serological monitoring
?
_______________ ___-______ is used for the discrimination between EHDV and BTV.
Multiplex real-time RT-PCRs
Palyam Virus is a species of _______ infecting ?
ORBIVIRUS, cattle and sheep.
Palyam virus is transmitted by _______ mosquitoes and _____ (CULICOIDES) that results in _________ and _____ diseases, as well as?
No ________.
culicine, gnats, Reproductive, CNS, abortion, congenital abnormalities,
hydraencephalopathy., vaccine
What virus is pictured here?
Rotaviruses
Rota means ______ shape, worldwide distribution
wheels
Rotavirus infects ________ _______ cells at the ____ of the intestinal _____ with resulting malabsorption,
maldigestion, and diarrhea
mature adsorptive, tips, villi
Rotaviruses are divided in different serogroups (or species) based on: _____
VP6
Rotavirus serotypes within serogroup-A are recognized
by: _____
VP7
In the case of NEONATAL Rotavirus infection, ______ immunity is more
important than circulating ______.
Local, antibody
(IgA = more superior in protection than IgG because it is circulating in blood/serum while A is in mucosal membranes in nasal, GI tract).
Rotavirus can be _______ and rapidly detected in _____ by the ELISA
sensitively, stools
The severity of rotavirus infection is determined by:
-The _______ of the infecting viral strain
-The _______ of virus ingested
-The level of _______-derived immunity
- ____ of the animal at the time of exposure and _________ factors
virulence, amount, maternally, Age, management
Describe the mechanism of Rotavirus
- Damage of the villi: shortened and covered with immature, less differentiated epithelia that
migrate from the crypts - NSP4: viral _________ & rotavirus stimulates ________: both activates _______ pathways:
- Increase ____cellular ___ concentration
- __________ secretion from the crypts
- _____________ diarrhea
- _______ loss of ______ and _________
enterotoxin, neurotransmitters, secretory, intra, Ca, Chloride, Secretory, Rapid, water, electrolytes
What can be seen here?
Retrovirus attaching to a lymphocyte
Replication of Rotaviruses
When animal has diarrhea and loss of fluids, there is reduced ?
Rotaviruses are difficult to isolate in tissue culture from clinical samples. Addition of low concentrations of _______ to growth medium
facilitates viral ______ and improves viral _______.
trypsin, uncoating, replication
Diagnosis of Rotaviruses
- Proper sampling
- Detection of virus particles : EM
- Detection of virus Ag: IFT
- Detection of viral RNA: RT-PCR
Rotavirus
Animal rotaviruses can, in rare cases can be ________.
zoonotic
Rotavirus vaccines
* A live, oral, __________, human-bovine ________ vaccine
* Administered at 2, 4, and 6 months of age
* RotaTeqTM
* RotarixTm
pentavalent, reassortant
Avian Reovirus (ARV)-syndromes
causes ?
Viral arthritis/tenosynovitis
Fibrinous tenosynovitis
Stunting syndrome in broilers (outside of Reovirus, other bacteria contributing here).
Helicopter disease
- Viral arthritis/tenosynovitis
- lameness and swellings affecting primarily
tarsometatarsal joints and the feet - Many infected birds are in good general
condition, but some are lethargic and
exhausted
Fibrinous tenosynovitis inflammation of the tendon progresses to a chronic type lesion characterized by tissue fibrosis in the affected area
- Helicopter disease
- The growing primary wing feathers,
abnormally big for chickens with retarded
growth, protrude at various angles.
What condition is this animal suffering from?
Causative agent?
Helicopter disease
Avian reovirus
Avian Reovirus-syndromes-Diagnosis
* History, clinical signs, PM lesions
* Laboratory diagnosis
* Sampling (select the affected tissues )
* Isolation of the viruses by cell culture and ECE
* Detection of the virus by EM
* Detection of the virus nucleic acid by PCR
* Detection of the viral antigens and antibodies by ELISA,
NT etc
Arthritis lesion: pitting of the articular _______ over the distal _______ condoyle in the broilers.
What virus causes this pathology?
cartilage, tibiotarsal, Avian reovirus
Equine Encephalosis (EE) is an ___________-borne ______ , ______-contagious disease of _______.
arthropod, febrile, non, equines
Name the serotypes of EE?
Has several serotypes (EEV1-EEV7)
_______ and ______ can act as maintenance host of EE virus, making the
elimination of the virus difficult.
Zebra, elephants
EE virus
A novel real time Polymerase Chain Reaction (PCR) assay has also been developed
for the detection of EEV by targeting the gene ?
Viral Protein (VP)-7
Members of the genus Coltivirus?
Colorado Tick fever virus
Tick fever/Saddle-back fever
Colorado tick fever virus is a ______ disease that occurs in ____-altitude ____ habitats
* [1000 – 3000 metres] – in the ____ Mountain region of USA
zoonotic, high, forest, Rocky
Colorado tick fever virus is Transmitted by?
wood tick – Dermacentor andersoni
Colorado tick fever virus
________ ticks transmit the virus mainly to _____ mammals such as?
Nymphal, small, squirrels, rats, and other rodents
This animal is suffering from what virus?
What genus does this virus belong to?
What species are typically affected?
Results in?
Grass Crap Reovirus (GCRV)
Genus: AQUAREOVIRUS
Affects Fish and shellfish
results in : Focal hepatic necrosis, hemorrhagic lesions in many tissues
Members of the family Birnaviridae
Genome: ____ _____-stranded RNA segments (2.9 to 3.6 kbp) with the RNA-dependent RNa polymeraase covalently linked to the __‘-end of the genomic positive-strand.
Two, double, 4
What virion is pictured below?
Family: Birnaviridae
What virion is pictured below?
Family: birnaviridae
2 DS RNA
Name the three genuses that fall under the family Birnaviridae
Name the viral species that fall under Aquabirnavirus
Infectious pancreatic necrosis virus (IPNV)
Name the viral species that fall under Avibirnavirus
Infectious bursal disease virus (IBDV)
Name the viral species that fall under Entomobirnavirus
Drosophila X Virus (DXV)
The family Birnaviridae genome is ?
dsRNA
Name the hosts that carry the viruses under the family Birnaviridae
Vertebrates, invertebrates
Under the genus Birnaviridae, the genus Blosnavirus has one virus named?
Blotched snakehead virus
What Virus family possesses this genome?
Segment A possesses?
Segment B possesses?
Birnaviridae
Segment B: ORF3 includes Viral protein 1.
Segment A: ORF1 includes VP5, ORF2 includes VP2,3,4 (ORF2 is important for vaccine development?)
_______ circularize segment A and B by binding their ends.
VPg
What virus has this genome? What is the family this virus falls under?
Infectious bursal disease virus
Birnaviridae
What virus has this genome? What is the family this virus falls under?
Infectious pancreatic necrosis virus
Birnaviridae
Birnaviridae
IBDV Replication strategy
Avibirnavirus -Infectious Bursal Disease virus (IBDV) (_________ disease)
* An acute, ______ __________ disease of chickens: significant economic losses. Additionally, this disease results in:
1. Mortality
2. Reduced performance and
3. _______________: increased susceptibility to other diseases
4. Tropism: the ______ of ______, an important organ in the young chickens developing immune system
* The second most important poultry disease after Newcastle disease
* Transmission: infected chickens shed the virus in their feces
* Other chickens in the house become infected by ingesting the virus from
contaminated feed, water and poultry house (oral rout)
*** Mechanical transmission among the farms by people, equipment and vehicles
* Occurrence: worldwide
Gumboro, highly contagious, Immunosuppression, bursa, Fabricius
IBDV-Resistance to physical and chemical agents
** Extremely ______ virus
* Tolerate a wide pH range (*pH (extremely acidic ___-__ extremely _______)
* Heat stable (still viable after 30 minutes at 60°C)
* High level of resistance to most commonly used disinfectants
* Survives in the poultry house environment for extended periods of time
stable, 2-12, alkaline
IBDV-Pathogenesis
* Initial replication occurs in the intestinal tract
within hours of ingestion of the virus.
* The virus then disseminates to numerous
lymphoid tissues including the bursa of
Fabricius, thymus, spleen and tonsils.
* Gross lesions include dehydration,
hemorrhage in the pectoral and leg muscles,
enlargement of BF with edema and hyperemia.
IBDV pathogenesis pathway
Classification of IBDV strains - Serotype 1
**Classification of IBDV Strains - Serotype 2
Benign serotype
IBDV
Classical or standard strain: 10-50% mortality
Variant virus: no mortality
Very virulent virus: 50-100% mortality
What viral disease is this animal suffering from?
IBDV
IBDV Clinical signs
* The most susceptible chickens
are of age 3 – 6 weeks.
* Soiled vent feathers
* ** _________
* ** __________
*** _________ feathers
* Anorexia
* Trembling
* Sever weakness
* Dehydration and eventually death
Diarrhea, Depression, Ruffled
IBDV Kidney embedded in the vertebral column of birds but in this scenario it is very chord like
IBDV
Various stages of hemorrhagic and severe hemorrhagic IBDV infection in bursa
IBDV
Areas of necrosis on right.
Bursa –> hemorrhage
Diagnosis of IBDV
* Clinical sings & PM lesions are highly suggestive
* Laboratory diagnosis
1.Proper sampling
2.Virus isolation
-ECE inoculation
-Tissue culture
3.Detection of viral Ag &Ab
-ELISA
-FAT
4.Detection of viral RNA
-RT-PCR
* Differential diagnosis
IBDV-Control
* Control may be facilitated by proper sanitation practices
* Vaccination programs are widely used to control IBVD
**** Both _________ and ______ vaccines are available
***** Broilers: in ___ vaccine at __ days of incubation: live attenuated virus:
produce an _______ immune response earlier in chicken life
** VP2 recombinant vaccine: produce a __________ immune response
* The complexity of poultry raising programs: no single vaccination program
for all the production systems and types of chickens
attenuated, killed, ovo, 18, active, protective
Virulence based classification of IBDV strains
?
Infectious Pancreatic Necrosis Virus of Fish (IPNV)
* _____ contagious and lethal of ______ & _______ and young Atlantic _____ fish
* Visceral organs (heart, liver, kidney, and spleen) ____
* ________ in intestine and ceca
* Small to large foci of necrosis of ____ cells of pancreas
Highly, salmonid, rainbow, salmon, pale, Hemorrhage, acinar
IPNV
IPNV
What viral disease is this animal suffering from? What are the clinical signs?
IPNV
A- Abdominal distention pale gills of trout
B- Hemorrhage in the intestine
C- Normal pancreases
D- Necrosis of pancreas
E- Gradient purified virus
-Pale enlarged liver and spleen
**- Frantic corkscrew swimming followed by periods of rest
How do you diagnose IPNV?
Diagnosis
Signs, PM, Pathology
**Virus ________ on standard fish cell lines
*** ______is the best organ of choice for virus isolation
*Detection of viral Ag: IFA, SNT, ELISA
*Detection of viral RNA: RT-PCR
Diagnosis
Signs, PM, Pathology
**Virus isolation on standard fish cell lines
***Kidney is the best organ of choice for virus
isolation
*Detection of viral Ag: IFA, SNT, ELISA
*Detection of viral RNA: RT-PCR
- ‘Picobirnavirus’ derives from the prefix
‘pico’ (latin for ‘_____’): small virion size - Prefix ‘bi’ (latin for ‘____’)
- ‘RNA’ to indicate the nature of the viral
genome
small, two
The genome of the family Picobirnaviridae?
What viral family is pictured below?
Picobirnaviridae
PBV detection in the environmental and food samples
Importance of environmental samples for early monitoring of viral diseases
PBV detection in various hosts and environment samples
15,20,25,25,35
