LEC 14 - Orbivirus + Rotavirus Flashcards
What is found in a necropsy of an animal who died of Orbivirus?
Ulcers on the tongue
Petechial hemorrhage along the esophagus/trachea
Pulmonary edema +/- CrV pneumonia
Severe hemorrhage in the abdomen
What are reoviridae viruses?
Respiratory enteric orphan viruses
What does it mean to be an orphan virus?
Researchers do not know if these viruses cause disease or not
What are the two groups of reoviridea viruses?
Orbivirus
– and –
Rotavirus
What disease does the oribivirus cause?
Epizoonotic hemorrhagic disease
Bluetongue
What is the structure of the orbivirus?
Spherical/icosahedral symmetry
Non-enveloped
What is the genome structure of orbiviruses?
Segemented dsRNA
What is the vector for Orbivirus?
Culicoides
(GNATS)
Where does the reoviridea viruses replicate in the host cell?
Cytoplasm
What is the sequence of events in reoviridea replication?
Attachment to host receptors+ Endocytosis
Partial uncoating in endolysozomes
Early transcription of genome by viral pol WITHIN VIRAL PARTICLE CYTOPLASM
mRNA segment translation
Aggregation + Encapsidation
Cell death
What animals are affected by bluetongue?
Sheep
What animals are affected by EHD?
Deer + Sheep
But sheep normally have zero to very little clincal disease
What is the host dependent preference of African Horse Sickness?
Horses > Mules > Donkeys
What protein is responsible for the serotypes of bluetongue?
VP2
What are the major serotypes of EHD? Where are they most commonly found?
EHDV-1: New Jersey
EHDV-2: Alberta
EHDV-6: US
Ibaraki virus: Japan
What is different about the way bluetongue presents?
5 to 10 year cycles
What is the host preference of EHD?
White tail deer > Mule deer > Elk
If you are infected with one serotype of EHD are you protected against other forms?
No, not cross-protective
What are the non-edemic bluetongue viruses?
BTV - 1, 4, 8, and 14
What are the endemic EHD viruses?
EHDV-1, 2, + 6
What is the time of pathogensis in a reoviridae infection?
7 to 10 days
How does reoviridae viruses pass through the body?
Blood to bone marrow
Secondary viremia
Endothelial cells
Edema + Hemrrhage + Thrombosis + DIC
What are the common clinical signs with Reoviridae viruses?
Fever > 106 deg.
Oronasal discharge
Hypersalivation
Oral necrosis
Coronary band damage + lameness
What are the two types of immunity that are induced by a reoviridae infection?
Homologous
– and –
Heterologous
What is the homologous immunuity induced by the reoviridae viruses?
Antibody mediated
T cell mediated
Directed at VP2 + VP5 proteins
What is the heterologous immunity induced by a Reoviridae infection?
Directed at NS1
Inner core proteins
What are the test used to make a reoviridae diagnosis?
AGID + ELISA = Blood
rtPCR
What is the treatment for reoviridae infections?
Palliative care
Chronic poor doers
What time of the year is orbiviral infections most common?
Fall
How many serogroups of the rotavirus are there?
7
What determines the serogroup of a rotavirus?
VP6
What is the structure of the rotavirus?
Non-enveloped
What does the rotavirus do to the host cell?
Cytolytic
Where does the rotavirus replicate in the host cell?
Cytoplasm
What is the structure of the genome of a rotavirus?
dsRNA
Segmented
How long does it take to see the pathogenesis of rotavirus?
24 hours
What is the transmission mechanism of a rotavirus?
Fecal-oral transmission
How does rotavirus travel in the body?
GI passage
Enterocytes
Loss of mature enterocytes at the tips of villi
Malabsorption + Secretions
How long till clinical signs of a rotavirus infection are seen?
3 to 4 days
What are the clincial signs of a rotavirus infection?
Non-bloody
+/- watery diarrhea
Concurrent infectoins
What are the methods used to diagnose a rotavirus infection?
Electron microscopy
Serogroup A ELISA/Latex agglutination
Fluorescent antibody test
What are the preventative measures that can be taken when dealing with rotavirus?
Management changes
Oral vaccine
What is the treatment for rotavirus?
Supportive
Management of concurrent infections
How does the reovirus avoid detection by the innate immune system?
Replicating its genome within the viral particle
What are the clincial signs of infectious bursal disease virus?
Depends on age
3 to 6 wks = moderate mortality
Later = mild infection
Depression + Inappetence + Diarrhea
What is seen upon histopathology of chickens with IBDV?
Cystic lesions
Interfollicular fibrosis
Follicular degeneration
What type of virus is IBDV?
Birnaviridae
What is the genomic structure of IBDV?
dsRNA
Linear
What is the structure of IBDV?
Non-enveloped
Where does IBDV replicate in the host cell?
Cytoplasm
What is the sequence of events when it comes to Birnaviridae replication?
Viral penetraion
Cytoplasm
dsRNA transcription w/i virion
+strand translation
+strand transcription
- strand pairing
Budding of mature virons
How long does it take for pathogenesis to start with IBDV?
1 to 2 days
What is the transmission mechanism of IBDV?
Fecal-oral
Where does IBDV target?
GI tissues
Liver - Kupfer cells
When secondary viremia of IBDV occurs where does it target?
B cells
What does it mean when lingering symptoms are seen with IBDV infections?
Immunosuppression
What tests can be done to diagnose IBDV?
Gross necropsy
ELISA
VI
rtRNA
What is the treatment for IBDV?
Depop/Repopulation
Vaccination (MLV + Killed + Recombinant)
What sample and test is good for ID’ing a IBDV infection?
Clocal swabs
