Block 3 Micro Exam -- Picornaviruses (#5)

Front 1

3 main genera within picornaviruses that infect humans

Back 1

Enteroviruses
Heparnaviruses
Rhinoviruses

Front 2

Poliovirus is part of what genera

Back 2

Enterovirus

Front 3

Where do they enteroviruses replicate

Back 3

GI tract
Transmitted by fecal-oral route

NOTE: do NOT cause severe GI disease

Front 4

Where do rhinoviruses replicate

Back 4

Nose & upper respiratory tract

Front 5

What is the site of recognition of picornaviruses for virus receptors?

Back 5

Cleft in VP1 protein

Front 6

These picornaviruses are NOT sensitive to acid pH

Back 6

Enteroviruses

Includes: poliovirus, coxsackie, echo, entero

Front 7

Capsid proteins are at what end of the picorna RNA

Back 7

5' end

Front 8

IRES

Back 8

Internal Ribosome Entry Site

Serves same purpose as RNA cap, which these do NOT have

Front 9

VPg

Back 9

Primer in RNA replication at 5' end
Removed to allow translation to begin

Front 10

Where does picornavirus replication take place?

Back 10

ENTIRELY in cytoplasm

Front 11

This event transforms procapsid into a mature capsid

Back 11

Proteolytic cut in one of the casid proteins

Front 12

How long does picornavirus replication cycle take?

Back 12

6 - 8 hours

Front 13

How do picornaviruses overhaul cellular machinery?

Back 13

Cleave and inactivate host protein that recognizes mRNA "cap"

Stops host cell synthesis
BUT, viral synthesis can continue due to IRES

Front 14

What type of paralysis does polio cause?

Back 14

Flaccid

From destruction of motor neurons

Front 15

Which polio serotype causes most paralysis?

Back 15

Serotype 1

Front 16

How does poliovirus spread in the body?

Back 16

Hematogenously

Front 17

How long is the incubation period of poliovirus?

Back 17

7 - 14 days

Front 18

Abortive polio

Back 18

~90% of cases or more

Sore throat or GI symptoms
NO neurological problems

Resolves in a few days

Front 19

Non-paralytic polio

Back 19

5% of cases

Back/Neck pain, muscle spasms
Spreads to CNS, but NO paralysis

Recovery is complete after 2-10 days

Front 20

Paralytic Poliomyelitis

Back 20

~1% of cases

ASYMMETRIC, FLACCID paralysis
May be accompanied by meningitis
NO SENSORY LOSS

Maximal recovery ~6 months
Recovery is almost NEVER COMPLETE

Recovery results in lifelong immunity

Front 21

Post-polio syndrome

Back 21

Muscle wasting and mild paralysis

Can occure 30 - 40 yrs after primary disease

NOTE: NO viral growth during this

Front 22

Binding of what can neutralize poliovirus?

Back 22

Neutralizing epitopes on VP1

Front 23

How long does passive immunity (mom-->kid) last against polio?

Back 23

~6 months

Front 24

What types of vaccines are available for polio?

Back 24

Killed (Salk)
Live attenuated (Sabin)

Front 25

Reservoirs for polio

Back 25

HUMAN ONLY

BUT, can be transferred to monkeys

Front 26

Seasonality of polio

Back 26

Temperate climate -- summer/early fall

Tropics -- all year long

Front 27

Age group most at risk for polio

Back 27

5 - 15 yr. olds

Front 28

Type A coxsackie only are most usually found in what diseases?

Back 28

Herpangina
Hand-foot-mouth
Acute hemorrhagic conjuctivitis

Think face/mouth

Front 29

Type B coxsackie only are most usually found in what diseases?

Back 29

Pleurodynia
Myocarditis
Meningoencephalitis

Think heart/chest/brain

Front 30

When are coxsackie virus infections most common?

Back 30

Summer

Front 31

How do coxsackie viruses spread within body?

Back 31

Hematogenously

Front 32

How long is the incubation period for coxsackie viruses?

Back 32

2 - 9 days

Front 33

Herpangina

Back 33

Severe febrile pharyngitis
Onset is abrupt
Only a few days duration (self-limiting)

Caused by some GROUP A coxsackie viruses
Pharynx has characteristic vesicles on palate

Can affect any age group, but children @ highest risk

Front 34

How is Hand-Foot-Mouth disease distinguished from Herpangina

Back 34

HFM lesions occur more towards ANTERIOR mouth
Palms and soles are involved in HFM

Front 35

HOw is HFM distinguished from chicken pox

Back 35

HFM almost always involves the mouth
Chicken pox makes people more sick

Front 36

Hand-Foot-Mouth Disease (HFM)

Back 36

Ulcers in mouth, and vesicular rash on palms/soles
Rash may spread to arms/legs

Most common in children

Caused by Group A Coxsackie viruses

Front 37

Pleurodynia

Back 37

Also called Bornholm's disease

Sudden onset fever and chest & ab pain
Pain worsened by movement and breathing

Caused by Group B Coxsackie

Most common in children
Lasts week or so
Relapses may occur

Front 38

Coxsackie-related myocarditis is worst in what age group?

Back 38

Newborns

Front 39

What viruses cause Acute hemorrhagic conjuctivitis

Back 39

Enterovirus 70
Coxsackie virus A24

Front 40

What is incubation period in case of acute hemorrhagic conjuctivitis?

Back 40

Very short - 24 hrs.
Cases resolve spontaneously in 1-2 weeks

Front 41

What other infections can coxsackie viruses cause?

Back 41

Coxsacikie A alone -- diarrhea
Coxsackie A & B -- common cold

Front 42

Seasonality of common cold

Back 42

Early Fall
Late Spring

Front 43

Non-rhinoviruses that cause common cold

Back 43

Parainfluenze
Adenoviruses
Coronaviruses
Enteroviruses

Front 44

What other animals canbe infected with rhinovirus?

Back 44

Gibbons
Chimps

Front 45

Conditions that rhinoviruses survive or succumb to

Back 45

Inactivated @ acid pH (3)
Replicate best @ 33 degrees C
Very stable to dehyrdation

Front 46

Most important methods of rhinovirus transmission

Back 46

Self inoculation (fingers, etc.)
Aerosol

Front 47

How long does it take for Ab to show for rhinovirus?

Back 47

7 - 21 days

NOTE: this is after disease has cleared (takes 3-7 days)

Ab is protective against subsequent infection of SAME serotype

Front 48

Why is rhinovirus vaccine unlikely?

Back 48

Poor growth in cell culture
TOO MANY serotypes

Front 49

Which picornavirus does NOT grow well in cell culture?

Back 49

Rhinovirus