Final: Reoviridae Flashcards
Mature reovirus particles are composed of what 3 concentric layers?
Outer
Middle/intermediate
Inner
The outer layer of reoviruses has what type of symmetry?
Icosahedral
What is the viral genome of reovirus composed of?
Segmented double-stranded RNA (dsRNA)
What does “Reo” stand for?
Respiratory enteric orphan
Does genetic reassortment between viruses with a genus or serogroup happen with reoviruses?
Yes
What diseases occur from genus orbivirus?
African horse sickness virus
Blue tongue virus
What disease occurs with rotaviruses?
RVA (group A rotavirus)
What disease occurs with orthoreovirus?
Avian reovirus
Which virus is an infectious, non-contagious, insect-borne disperse of domestic and wild ruminants caused by a member of Orbivirus?
Bluetongue, caused by Bluetongue virus
Who are the hosts of BTV?
Sheep (most common/susceptible)
Deer (white-tail)
T/F: Bluetongue is a List A disease of the office of international epizootics (OiE)
True
What are the routes of transmission of BTV?
Biologically by certain Culicoides
Less significant:
Trans-placental transmission
Venereal transmission
What is the pathology of BTV in sheep?
Damage to vascular endothelium Intravascular coagulation Necrosis of tissues and organs supplied by damaged capillaries Edema Hemorrhage Congestion Abortion CNS malformations
What are clinical signs of BTV?
Cyanosis, necrotic ulceration of tongue Erosion of dental pad, necrosis, hyperemia and ulceration in oral cavity Coronitis and laminitis causing lameness Extensive facial swelling Aborted, macerated fetuses
What are prevention methods of BTV?
Vaccines: attenuated vaccines, which are available in countries including the US, are generally serotype specific; polyvalent vaccines are available in South Africa, Israel and other countries
Vector control: use of repellents and insecticides, lodging animals indoors during night since Culicoides have nocturnal feeding habits, using nets in windows and doors of animals shelters, not allowing animals to graze near possible insect breeding area
What is African horse sickness (AHS)?
Infectious, non-contagious, arthropod-borne disease of horses, donkeys and mules
T/F: Dogs can contract a highly fatal form of AHS
True
Resulting from the ingestion of infected carcass material from horses that have died from AHS
T/F: AHS is also a list A infectious disease of the OiE?
True
Enzootic in sub-Saharan Africa, although occasional outbreaks have occurred in Northern Africa, Middle East and in Europe.
What causes AHS?
A virus in the genus Orbivirus
How do Culicoides transmit AHS?
Get blood meal from infected horses or zebra reservoirs -> healthy horses
Pathogenesis is the same as Bluetongue in sheep
What are the forms of AHS?
Acute (pulmonary) Horse sickness (Dunkop)
Subacute (cardiac) horse sickness (Dikkop)
How do we prevent and control AHS?
Vaccination in enzootic areas
Control vector population
Reduced exposure to biting insects
Slaughter of sick or viremic animals
What virus is a major cause of severe viral diarrhea in young mammals and birds
Rotavirus
T/F: based on differences in VP6 protein and VP6 gene, rotaviruses are classified into at least 6 groups/species, designated as RVA-RHV
False, 8 groups, not 6
RVAs are the most common cause of what in the young of humans and a wide variety of animal species and birds?
Viral diarrhea
What is the transmission of rotavirus in animals and humans?
Infected stool contains large number of viruses
Fecal-oral transmission is the most likely route of rotavirus spread
Virus can survive in environment, is resistant to common disinfectants, and can be transmitted through contaminated objects, water or food
The main site of viral multiplication is the mature enterocytes on the villi of upper small intestine
What are the symptoms common with rotavirus?
Severe diarrhea in young animals
Profuse diarrhea, anorexia, dehydration and occasionally mild fever
Uncomplicated cases usually recover within 3-4 days
What are the vaccines available for rotavirus?
Equine RV Vaccine
Bovine RV Vaccines:
Adjuvanted. Bovine rota-coronavirus inactivated virus, Cl perfringens type C toxoid, Escherichia coli Bacterin. For vaccination of healthy, pregnant cows.
[Bovine rotavirus-coronavirus vaccine, killed virus, Clostridium perfringens types C and D Escherichia coli bacterin-toxoid]. For vaccination of healthy pregnant cows.
Are rotaviruses zoonotic?
YES
What is avian reovirus?
Avian reoviruses are involved in a variety of disease conditions in domestic poultry of which the most important is viral arthritis/tenosynovitis in chickens
Who are the hosts of avian reovirus?
Broilers tend to get viral arthritis/tenosynovitis and leg weakness.
What is the transmission of avian reovirus?
Fecal-oral route
Transovarial
Inhalation
What is the pathogenesis of avian reovirus?
After intestinal replication, the virus spreads via the bloodstream to all parts of the body.
Pathogenic viruses localize in the hock joint, where they cause arthritis
What are the clinical findings with avian reovirus?
Lameness Viral arthritis/tenosynovitis Swollen and inflamed hock joints Clear synovial fluid and inflammation of synovial membranes Ruptured gastrocnemius tendons
How can we prevent avian reovirus arthritis?
Lived and killed vaccines are available.
Since chicks are the most susceptible to avian reovirus infection immediately after hatching, vaccine protocols aim at offering passive immunity to chicks from maternal antibody following vaccination of the hen, or by active immunity after early vaccination with a live vaccine.
Can you name the common biological vector of BTV?
Culicoides
Rotavirus is primarily transmitted by ____?
Fecal-oral route
Dunkop and Dikkop forms are clinical forms of _____?
African Horse Sickness
