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Flashcards in bunyaviridae Deck (16):
1

bunyaviridae general

virions spherical, enveloped, glycoprotein spikes, no matrix protein, three nucelocapsid segments with helical symmetry, segmented negate sense, ssRNA
three segments large L medium M and S small, cytoplasmic replication, cytocidal for vertebrate cells, genetic reassortment can occur between the segments, budding into golgi

2

bunyavidirdae genera

arthropod borne-orthobunyavirus-akbane virus
phlebovirus-rift valley fever
non arthropod-borne-hantavirus-hantaan virus

3

phlebovirus->rift valley fever

sheep cattle goats, percutaneous or aerosol exposure to humans or bites may infect humans, humans prob dead end hosts, located in rift valley

4

rift valley fever biological transmission

primary vector= Aedes
Secondary vector: Culex and Anopheles, culicoides (mechanical)

5

rift valley fever transmission

enzootic cycle -mosquitoes
epizootic-heavy rainfall, massive mosquito out break all lead to human epidemic, very high newborn death rate

6

rift valley fever transmission 2

the virus is transmitted transovarially among floodwater, virus can survive in mosquito eggs Aedes increase with heavy rains, infected could become viremic, high proportion of animals and humans at risk because of amplification with biting midges

7

Rift valley virus path

rapid replication and reaches high titer, virus replicates in liver and other major organs cause widespread necrosis, encephalitis, hepatic necrosis, renal failure, and shock, 90-100% of pregnant animals abort

8

Rift valley sheep clinical signs

mortality in young lambs, young animals surviving the hepatic infection may show encephalomyelitis,90-100 percent ewes abort; less sever in cattle but same signs

9

rift valley fever Dx

should be expected after heavy rains

10

rift valley control

attenuated vaccines, inactivated vaccine in vitro both produced from mouse brain, vector control also important

11

Akabane-orthobunyavirus

congenital disease of cattle, sheep, goats
transmission-biting midges and mosquitos

12

aka bane path

bite and pregnant ruminant infected, virus reaches fetus from maternal circulation, most severe fetal lesions in cattle occur during infection within 3-4 months of gestation, encephalomyelitis, hydraencephaly, arthrogryposis

13

akabane clinical signs

not usually seen in young animals, can cause seat or abotion of baby or premature birth and hydraencephaly, arthrogryposis

14

akabane Dx

look for neutralizing antibody in serum collected from aborted fetuses or from newborn calves, kids, or lambs before ingestion of colostrum, must be isolated from placenta

15

akabane control

reportable disease, inactivated vaccine available in japan and australia

16

SCMALLENBERG virus

similar to akabane yet produces malformed animals an shows as diarrhea, abortion and reduced milk production in adult ruminants