Togaviridae

Question 1

Togaviridae: general

Answer 1

spherical, enveloped with 80 spikes

Question 2

Alphaviruses genome

Answer 2

linear, positive sense, ssRNA

Question 3

Alphavirus causes

Answer 3

Equine viral encephalitis

west, east, venezuelan

Question 4

EEEV: transmission and reservoir

Answer 4

Mosquitos
Passerine birds (also amplifiy virus)- asymptomatic, some CNS signs

Question 5

EEEV: replication in (cells)

Answer 5

myocytes, fibroblasts, reticuloendothelial cells, lymphoid cells, osteoblasts

Question 6

EEEV: pathogenesis

Answer 6

Virus enters CNS via hematogenous, replication in neurons, vascular endothelal, and glial cells
apoptosis of those cells
non-suppurative encephalomyelitis

Question 7

EEEV: CS in horses

Answer 7

fever, anorexia, depression, hypersensitive to sound

CNS signs, paralysis, unable to hold head up, ataxia, tremors of face and shoulder muscles

Question 8

EEEV: CS in humans

Answer 8

Systemic-fever, malaise, arthralgia, myalgia
No CNS involved
Encepthalitic- anorexia, vomiting, diarrhea, cyanosis, convulsions, coma
may result in death or brain damage

Question 9

T or F

WEEV is more virulent in horses and humans than EEVE

Answer 9

False

WEEV appears to be less virulent

Question 10

WEEV: reservoirs for urban and wildlife cycles

Answer 10

Urban- Birds

Wild- black tailed jack rabbits, Prairie dogs

Question 11

WEEV: CS in horses

Answer 11

mild or asymptomatic, severe appears similar to EEEV

Question 12

WEEV: CS in humans

Answer 12

mild in adults

severe encephalitis in children

Question 13

VEEV subtypes I-A, B, C are in the ___ cycle and are ___ virulent in horses

Answer 13

Epizootic/epidemic

Highly virulent

Question 14

VEEV subtypes I-D, E, F are in the ___ cycle and are ___ virulent in horses

Answer 14

Enzootic/endemic
Not virulent
includes subtypes II-IV

Question 15

VEEV: reservoir

Answer 15

Rodents

Question 16

VEEV: CS in horses

Answer 16

mild with fever

anorexia, depression, non-suppurative encepahlomyelitis, seizures, CNS

Question 17

T or F

In-utero infection is possible with VEEV?

Answer 17

True

Question 18

VEEV: CS in humans

Answer 18

mild, systemic disease
flu-like, encephalitis
Preg- placental damage, fetal encephalitis, abortion/stillbirth

Question 19

equine encephalitis: diagnosis

Answer 19

CS, necropsy, histopath, isolation, PCR, hemaggulation inhibition, complement fixation

Question 20

equine encephalitis: control

Answer 20

Pest control

vaccine (unlicensed, some success)