Reoviridae Flashcards
Describe the general properties of Reoviruses.
-mature viral particles = 3 concentric layers
>outer (icosahedral symmetry), middle/intermediate, inner
-viral genome = segmented double stranded RNA
-genetic reassortment between virus within genus or serogroup
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Describe the classification of family in Reoviridae.
Describe blue tongue virus (BTV) general characteristics, hosts, & transmission.
- General characteristics
-inf, non contagious, insect borne dz of domestic & wild ruminants
-member of genus Orbivirus (etiology) - Hosts: most sus/common
>sheep (fine wool & mutton breeds in Europe)
>deer (white tailed) - Transmission:
>major route = biologically by spp of Culicoides (biting midge)
>trans placental = cattle & sheep
>veneral = semen of inf bull to sus cows
*LIST A DZ IN OIE
Describe the pathology of BTV in sheep.
-damage to vascular endothelium
-intravascular coagulation
-necrosis of tissues & organs
-edema
-hemorrhage
-congestion
-abortion
-CNS malformations
Describe clinical findings of BTV in sheep.
-cyanosis, necrotic ulceration of tongue
-erosion of dental pad, necrosis, hyperemia, ulceration in oral cavity
-coronitis & laminitis causing lameness
-extensive facial swelling
-aborted, macerated fetus
Describe the prevention of BTV.
-vaccine: attenuated vacc = avail in countries incl US (serotype specific)
-polyvalent vaccines avail in South Africa, Israel, other
-vector control
>use repellents & insecticides
>lodge animals indoors during night
>nets in windows & doors of shelters
>not allowing animals to graze near possible insect breeding sites
Describe African horse sickness (AHS).
-inf, non contagious, arthropod borne dz of horse, donkey, mules
-dogs contract fatal form by ingestion of inf carcass material from horses that have died from AHS
-LIST A INF DZ OIE
-enzootic in sub Saharan Africa although occasional outbreaks in North Africa, Middle East, & Europe
-etiology by virus in genus Orbvirus
-transmission by field vectors of Culicoides
>zebras act as reservoir (in apparently inf)
Describe the clinical findings of AHS.
-acute pulmonary horse sickness (Dunkop)
-subacute cardiac horse sickness (Dikkop)
Describe the prevention & control of AHS.
-vacc in enzootic areas
-control of vector pop
-reduced exposure to biting insects
-slaughter of sick or viremic animals
Describe Rotavirus.
-cause of severe viral diarrhea in young of mammals & birds
-structure & classification based on differences in VP6 protein & VP6 gene, rotavirus classified into 8 groups/species designated as RVA-RVH
-RVAs (group A rotavirus) most common cause of viral diarrhea in young of humans & variety of animals species & birds
Describe rotavirus transmission in animals & humans.
-inf stool has lg # of viruses
-fecal oral transmission
-virus survive in environment & resistant to common disinf & can be transmitted thru contam objects, water, food
-main site of viral multiplication is mature enterocytes on villi of upper SI
ZOONOTIC
Describe the rotavirus symptoms & vaccines.
-severe diarrhea in young of diff animals
-profuse diarrhea, anorexia, dehydration, mild fever
-uncomplicated cases recover in 3-4d
Describe avian reovirus.
-domestic poultry
-host: viral arthritis/tenosynovitis in chickens (meat type broilers) = leg weakness
-transmission: fecal oral route, transovarial, inhalation
-pathogenesis: intestinal replication -> bloodstream
>pathogenic viruses localize in hock joint & cause arthritis
Describe avian reovirus clinical findings.
-lameness
-viral arthritis/tenosynovitis
-swollen & inflamed hock joints
-clear synovial fluid & inflammation of synovial membranes
-ruptured gastrocnemius tendons
Describe the avian reovirus prevention.
-live & killed vacc
-chicks most sus after hatching
>vacc offer passive immunity to chicks from maternal Ab following vacc of breeder hens or active immunity after early vacc w live vaccine
