Micro Enteric Viruses 1 Flashcards Preview

ABBEY MSII U6 > Micro Enteric Viruses 1 > Flashcards

Flashcards in Micro Enteric Viruses 1 Deck (28):
1

rotavirus virology

double layered naked icosahedral capsid, segmented RNA genome (allows for reassortment) double stranded; environmentally rugged

2

rotavirus pathogenesis

fecal-oral, mostly peds (contaminated toys). attach, replicate in cell, epithelial cells die and fluids exit body as self limiting diarrhea with risk of dehydration

3

how does rotavirus attach to epithelial cell lining?

VP4 spikes

4

what does rotavirus primarily infect? what does this cause?

cells of the small intestinal villi - impaired villus function leads to impaired hydrolysis of carbs (malabsorption)

5

what causes the profuse watery diarrhea associated with rotavirus?

rotavirus nonstructural protein 4 (NSP4) that acts like an enterotoxin interfering with sodium transport pumps

6

who does rotavirus infect?

children 4-24 months. adults have a few days of nausea, anorexia, and cramping pain - newborn infants seem more resistant

7

exam for rotavirus

history of exposure; bloodless diarrhea young children with vomiting, anorexia, low fever, cramps, dehydration

8

rotavirus treatment

most cases - no treatment. oral rehydration (pedialyte and rice-lyte)
-RotaTeq and Rotarix vaccines help reduce severity
-NO antiemetic or antidiarrheal

9

norovirus virology

+ ssRNA, naked icosahedral capside, environmentall rugged, extremely contagious, low ID

10

norovirus clinical disease - symptoms and patients

gastroenteritis - older age cohort than rotavirus, fecal-oral (contaminated food), more vomiting

11

norovirus pathogenesis

-infection damages microvilli in small intesting (malabsorption)
-vomiting caused by change in gastric motility and delayed gastric emptying
-typically lasts 24-48 hr

12

what are the implications of a short course with norovirus?

less dehydration (that combined with the older population of patients as compared to rotavirus)

13

norovirus exam

profuse, non bloody vomiting; nausea, cramps, headache, low fever (mostly stay in gut), muscle aches, chance of dehydration

14

norovirus treatment

rest, rehydration, antidiarrheas in adults

15

what are the picornaviruses that cause enteric disease?

poliovirus, coxsackievirus, hepA

16

picornavirus virology

+ ssRNA genome; environmentally rugged
-includes both rhinoviruses (resp) and enteroviruses (polio, coxsackie, hepA)

17

biphasic infection

PICORNAVIRUS ENTEROVIRUSES
primary replication in gut with viremia and spread to regional lymph nodes leading to febrile illness and occasional CNS involvement
-may have DUAL TROPISMS replicating in both epithelium and lymphoid cells

18

what are the two poliovirus vaccines?

inactivated: must be injected, used in first world where already irradicated
attenuated: weakened, taken orally, used in eradication effeorts

19

poliovirus pathogenesis

fecal-oral enteric infection using CD155 receptor to enter - infects epithelial/lymphoid cells in gut

20

CD155 and polio

how polio enters cells - present on both epithelial/lymph cells in gut AND on gray matter CNS cells

21

where does polio MC infect the CNS?

anterior horn motor neurons of spinal cord (muscle symptoms) and brain stem (respiratory symptoms)

22

signs of CNS involvement with polio

flaccid asymmetric weakness and muscle atrophy due to loss of motor neurons and denervation of associated skeletal muscle

23

risk factors for CNS progression with polio

young age, advanced age, recent hard exercise, tonsillectomy, pregnancy, immunosuppression

24

poliovirus diagnosis on exam:

nonparalytic poliomyelitis or -preparalytic: generalized nonthrobbing headache, fever, sore throat, anorexia, n/v, muscle aches - symptoms subside in 1-2 weeks
-progression to CNS involvement: headache and fever, irritability, restlessness, apprehensiveness, emotional instability, stiffness of neck and back

25

polio diagnosis: tests

lumbar puncture: fluid pressure increased, pleocytosis, elevated protein, virus culture
MRI: anterior horn inflammation

26

polio treatment

no specific treatment exisits - supportive care
-positive pressure ventilation for those with respiratory failure
-physical therapy

27

postpolio syndrome

-new history of decreased muscle strength, weakness, and atrophy
-decades after polio
-fatigue, muscle and joint pain, cold intolerance
-NOT infectious: increasing dysfunction of surviving neurons

28

similarities between picornaviruses, noroviruses, and rotaviruses

small, naked, icosahedral RNA viruses; widespread worldwide, environmentally rugged, fecal-ral transmission
-all can cause self-limited GI illness, usually resolves with no med intervention - dehydration MC complication
-pediatric - younger the worse (coxsackie B 10% lethal)